HK1098167A - Polyester compositions for calendering - Google Patents
Polyester compositions for calendering Download PDFInfo
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- HK1098167A HK1098167A HK07104554.3A HK07104554A HK1098167A HK 1098167 A HK1098167 A HK 1098167A HK 07104554 A HK07104554 A HK 07104554A HK 1098167 A HK1098167 A HK 1098167A
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Description
Technical Field
[0001] The present invention relates to a polyester composition for calendering and, more particularly, to a polyester composition capable of having higher productivity in a calendering process. The invention also relates to a process for calendering such polyester compositions and to polyester films or sheets produced therefrom.
Background
[0002] Calendering is a process for economically and efficiently producing films and sheets from plastics such as plasticized and rigid polyvinyl chloride, abbreviated as "PVC", and polypropylene compositions. The thickness of the films and sheets is often between 2 mils (0.05mm) and 80 mils (2.0 mm). Calendered PVC films or sheets are readily thermoformed into various shapes and can be used in a wide variety of applications including packaging, slot liners, graphic arts, transaction cards, security cards, decorative covers, wallpaper, book binding, file folders, floor tiles, and products to be printed, decorated, or laminated in a secondary operation. Further discussion of polypropylene resin compositions used in calendering processes can be found in Japanese patent application No. Hei 7-197213 and European patent application No. 0744439A 1.
[0003] In contrast, the conventional process for processing polyester into films or sheets involves extruding a polyester melt from various flat dies. The thickness across the width of the sheet is controlled by manual or automated die lip adjustment. The melt sheet was quenched with a water-cooled chill roll and provided with a smooth surface finish. While extrusion processes produce high quality films and sheets, extrusion processes do not have the productivity and economic advantages of calendering processes.
[0004] PVC compositions account for the greatest specific gravity in commercial calendered films and sheets. Small amounts of other thermoplastic polymers, such as thermoplastic rubbers, certain polyurethanes, talc-filled polypropylene, acrylonitrile/butadiene/styrene terpolymers (ABS resins) and chlorinated polyethylene, are sometimes also produced by calendering. In contrast, polyester polymers, such as polyethylene terephthalate, abbreviated herein as "PET", or poly 1, 4-butylene terephthalate, abbreviated herein as "PBT", are difficult to successfully calender. For example, PET having an intrinsic viscosity of 0.6dL/g generally has insufficient melt strength to operate properly on calendering rolls. Melt strength is defined as the ability of a polymer to support its own weight in the molten state. In calendering, melt strength is related to the ability to remove the film from the roll process without deformation. For example, during press delay, polymers with low melt strength will sag and fall quickly; whereas a polymer with high melt strength will retain its shape for a much longer time and can be further processed. Melt strength is therefore critical to minimize the amount of "sag" and gravity-induced sag experienced by the polymer during calendering. In calendering, "sag" is defined as the reduction in thickness between the calender roll and the take-up system, expressed as the ratio of the nominal thickness or width of the film as it emerges from the calender roll to the same size at the take-up roll. Furthermore PET and other polyester polymers tend to crystallize at typical processing temperatures of 160 ℃ to 180 ℃, resulting in non-uniform quality, which in turn results in high forces on the calender bearings. Increasing the processing temperature reduces melt viscosity and improves processability. However, higher temperatures can cause, for example, degradation of the polyester due to thermal degradation, hydrolysis of the polymer due to exposure to moisture, and the formation of color bodies. Typical PET polymers also have a tendency to stick to the calendering rolls at higher processing temperatures. Calendering of various polyester compositions and some methods to address these issues have been described, for example, in the following patents: U.S. patent 5,998,005; 6,068,910, 6,551,688; U.S. patent application serial No. 10/086,905; japanese patent application Nos. 8-283547, 7-278418, 2000-243055, 10-363908, 2000-310710, 2001-331315, 11-158358; and international patent application No. 02/28967. While some of the above difficulties can be avoided by careful selection of polymer properties, additives, and processing conditions, it is still difficult to calender polyesters at high production rates.
[0005] The production rate in a calendering process, commonly referred to as line speed, depends on several factors. For example, equipment design and capacity can have a significant impact on how quickly and efficiently a calendering process will proceed. However, without equipment limitations, the line speed and efficiency of the calendering process is largely dependent on the material being calendered.
[0006] The higher the line speed, the more chance of melt fracture. Melt fracture gives the material a rough, tarnished or hazy appearance and is the result of the material's inability to respond to applied shear during processing. Melt fracture occurs when the calendering roll wall shear stress is greater than a certain value (typically 0.1 to 0.2MPa), and the onset of melt fracture is often the rate determining step in the calendering process. Shear stress is controlled by the volumetric productivity or line speed (which determines the shear rate) and the viscosity of the polymer melt. By reducing the linear velocity or viscosity at high shear rates, wall shear stress will be reduced and the chance of melt fracture will be reduced. Thus, reducing shear stress will reduce the chance of melt fracture as the calendering line speed increases. The problem of reducing shear stress and melt fracture in polyesters in extrusion processes has been addressed. For example, U.S. patent 6,632,390 describes a process for producing profiled extrudates in which the processability of polyester compositions is improved by the addition of branching agents which impart higher melt strength and higher shear thinning sensitivity. The polyester composition has an intrinsic viscosity of at least 0.65 dL/g. In calendering processes, however, polyester polymers often exhibit less sensitive shear thinning response (i.e., little change in the melt viscosity of the polymer between low and high shear rates) than PVC or polypropylene, which is typically processed by calendering. Thus, if a polyester with a higher melt viscosity is used to achieve sufficient melt strength, excessive force is often applied to the calender roll bearings due to shear thinning which is not sensitive enough. Increasing the processing temperature reduces the occurrence of melt fracture during calendering, but, as noted above, results in both polymer degradation and unsatisfactory polymer melt strength. Thus, difficulties in shear response and melt strength often prevent polyester polymers from being calendered at high line speeds and/or at lower processing temperatures to achieve the best product quality and lowest production cost. To address these issues, polyesters that can be calendered at high line speeds and/or at lower processing temperatures are needed.
Disclosure of Invention
[0007] We have determined that: polyesters with a proper balance of intrinsic viscosity and branching have excellent processing characteristics during calendering. We have surprisingly found that polyester compositions having higher yields in the calendering process can be made from polyesters having a crystallization half time of at least 5 minutes and an intrinsic viscosity of from 0.55 to 0.75dL/g, a branching monomer, and a mold release additive. Accordingly, our invention provides a polyester composition for calendering comprising (a) a polyester comprising diacid residues, diol residues and branching monomer residues, wherein said polyester is a random copolymer having a crystallization half time from the molten state of at least 5 minutes and an intrinsic viscosity of from 0.55 to 0.75 dl/g; and (b) an additive effective to prevent the polyester from sticking to the calender rolls. Our novel polyester compositions unexpectedly combine good melt strength with good shear response, allowing higher calendering line speeds before melt fracture occurs. Higher calendering line speeds in turn allow for more economical production of polyester sheets or films for industrial applications.
[0008] Our invention also provides a process for the processing of films and sheets comprising calendering a polyester comprising:
(a) a polyester composition having a crystallization half time from the molten state of at least 30 minutes and an intrinsic viscosity of from 0.55 to 0.75dL/g, wherein the polyester is a random copolymer comprising:
(i) diacid residues comprising at least 80 mole percent, based on the total moles of diacid residues, of residues of one or more of the following acids: terephthalic acid, naphthalenedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid or isophthalic acid;
(ii) diol residues comprising 10 to 100 mole percent of residues of 1, 4-hexanedimethanol, based on the total moles of diol residues, and 0 to 90 mole percent of residues of one or more diols selected from the group consisting of: ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, diethylene glycol, 1, 6-hexanediol, 1, 8-octanediol, 2, 4-trimethyl-1, 3-pentanediol, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, 1, 3-cyclohexanedimethanol, bisphenol a, and polyalkylene glycol; and
(iii) a branched monomer residue comprising 0.05 to 1 weight percent, based on the total weight of the polyester, of one or more monomers comprising 3 or more carboxyl substituents, hydroxyl substituents, or a combination thereof; and
(b) an additive effective to prevent the polyester from sticking to the calender rolls. The invention further provides polyester films or sheets produced by the calendering process described herein. Our polyester compositions, films or sheets may also include plasticizers and/or flame retardants to increase their flexibility and enable their use in industrial applications requiring flame retardancy. Films and sheets have excellent appearance, flexibility and flame retardancy and can be used in many decorative and packaging applications. The films or sheets are readily thermally processed into shapes for a variety of food and non-food packaging applications. They can be printed with a wide variety of inks and laminated with fabric or other plastic films or sheets, either on-line or off-line. Some specific end uses include graphic arts, transaction cards, security cards, decorative covers, wallpaper, bookbindings, folders, and the like.
Detailed Description
[0009] Polyester compositions are generally difficult to intervene in the calendering process for producing the film or sheet. As noted above, heretofore polyesters have not achieved the proper combination of melt strength and shear thinning that allows calendering at high line speeds and at lower temperatures. The ideal polyester should therefore have high melt strength and sensitive shear thinning to allow the polyester to operate at the high speeds associated with high efficiency industrial calendering without sagging or melt fracture.
[0010] The polyester compositions provided by the present invention have high melt strength and sensitive shear thinning properties, making them suitable for high speed calendering processes. Accordingly, in a general embodiment, the present invention provides a polyester composition for calendering comprising: (a) a polyester comprising diacid residues, diol residues and branching monomer residues, wherein the polyester is a random copolymer having a semi-crystallization time from the molten state of at least 5 minutes and an intrinsic viscosity of from 0.55 to 0.75 dl/g; and (b) an additive effective to prevent the polyester from sticking to the calender rolls. The combination of intrinsic viscosity (hereinafter abbreviated as "i.v.") and branching agent imparts higher melt strength and more sensitive shear thinning to the polyester, which allows our novel polyester compositions to be calendered at high line speeds at lower temperatures without excessive sag of the resulting film or sheet. The polyester composition may also contain one or more plasticizers to increase the flexibility and softness of the calendered polyester film, improve the processability of the polyester and help prevent the polyester from sticking to the calendering rolls. The invention also provides a process for producing a film or sheet by calendering the novel polyester composition and a film or sheet produced by such calendering process. Typical thicknesses for the calendered film or sheet range from 2 mils (0.05mm) to 80 mils (2 mm).
[0011]Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Further, the ranges set forth in the disclosure and claims are intended to specifically encompass the entire range and not just the two extremes. For example, the range of 0 to 10 is intended to include all integers between 0 and 10, such as 1, 2,3, 4, etc.; all fractions between 0 and 10, such as 1.5, 2.3, 4.57, 6.1113, etc., and the endpoints 0 and 10. Likewise, ranges associated with chemical substituents, such as "C1-C5 hydrocarbon" are meant to specifically include and disclose C1And C5Hydrocarbons and C2、C3And C4A hydrocarbon.
[0012] Notwithstanding that the numerical values and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0013] The term "polyester", as used herein, is intended to include "copolyesters" and is understood to mean a synthetic polymer produced by the polycondensation of one or more difunctional carboxylic acids with one or more difunctional hydroxyl compounds. Generally, the difunctional carboxylic acid is a dicarboxylic acid and the difunctional hydroxyl compound is a dihydric alcohol, such as glycols and diols. Alternatively, the difunctional carboxylic acid may also be a hydroxy carboxylic acid such as p-hydroxybenzoic acid, and the difunctional hydroxy compound may be an aromatic nucleus bearing 2 hydroxy substituents such as hydroquinone. The term "residue", as used herein, refers to any organic structure that enters a polymer or plasticizer by involving a polycondensation reaction of the corresponding monomer. The term "repeat unit", as used herein, refers to an organic structure containing a dicarboxylic acid residue and a diol residue bonded through a carbonyloxy group. Thus, the dicarboxylic acid residues may be derived from dicarboxylic acid monomers or their associated acid halides, esters, salts, anhydrides, or mixtures thereof. Thus, as used herein, the term dicarboxylic acid is intended to include dicarboxylic acids and any derivatives of dicarboxylic acids suitable for polycondensation with diols to make high molecular weight polyesters, including the associated acid halides, esters, half-esters, salts, half-salts, anhydrides, mixed anhydrides, or mixtures thereof.
[0014] The polyester compositions of the present invention are made from polyesters comprising dicarboxylic acid residues, diol residues and branching monomer residues. The polyesters of the invention contain substantially equal molar proportions of acid residues (100 mole%) and diol residues (100 mole%) which react in substantially equal proportions such that the total number of moles of repeat units is equal to 100 mole%. Thus, the mole percentages given in this disclosure may be based on the total moles of acid residues, the total moles of diol residues, or the total moles of repeat units. For example, a polyester containing 30 mole% isophthalic acid relative to total acid residues refers to a polyester containing 30 mole% isophthalic acid residues out of 100 mole% total acid residues. There are therefore 30mol isophthalic acid residues per 100mol acid residues. In another embodiment, a polyester containing 30 mole% ethylene glycol residues relative to total glycol residues means that the polyester has 30 mole% ethylene glycol residues out of 100 mole% of the diol residues contained. Thus, there are 30 moles of ethylene glycol residues per 100 moles of glycol residues.
[0015] The semicrystalline time of the polyesters of the invention from the molten state is at least 5 minutes. The semi-crystallization time may be, for example, at least 7 minutes, at least 10 minutes, at least 12 minutes, at least 20 minutes, and at least 30 minutes. Typically, the polyester having a crystallization half time of at least 5 minutes is a copolyester or a random copolymer. The term "random copolymer," as used herein, refers to a polyester comprising more than one diol and/or diacid residues, wherein the different diol or diacid residues are randomly distributed along the polymer chain. Thus, the polyesters of the present invention are not "homopolymers" or "block copolymers" as understood by those skilled in the art. Preferably, the polyester has a substantially amorphous morphology, meaning that the polyester comprises substantially disordered polymeric domains. Amorphous or semi-crystalline polymers generally have only one glass transition temperature (abbreviated herein as Tg) or one glass transition temperature and one melting point (abbreviated herein as Tm), as determined by well-known techniques such as differential scanning calorimetry ("DSC"). The desired kinetics of crystallization from the melt can also be achieved by the addition of polymer additives such as plasticizers or by altering the molecular weight characteristics of the polymer. The polyesters of the invention may also be miscible blends of substantially amorphous polyesters with higher crystallinity polyesters, both in a proportion to achieve a semicrystalline time of at least 5 minutes. In a preferred embodiment, however, the polyesters of the invention are not blends.
[0016] The semi-crystallization time of a polyester, as used herein, can be determined by methods well known to those skilled in the art. For example, the half-crystallization time can be determined by a Perkin-Elmer DSC-2 type differential scanning calorimeter. The half-crystallization time from the molten state was determined by the following procedure: a15.0 mg sample of polyester was sealed in an aluminum crucible and heated to 290 ℃ at a rate of 320 ℃/min for 2 minutes. The sample was then immediately cooled to the predetermined isothermal crystallization temperature in the presence of helium at a rate of about 320 deg.c/min. Isothermal crystallization temperature is the temperature at which the crystallization rate is greatest between the glass transition temperature and the melting point. Isothermal crystallization temperatures have been found, for example, in Elias, h.macromolecules, Plenum Press: NY, 1977, p 391. The crystallization half time is defined as the time elapsed from the isothermal crystallization temperature to the crystallization peak on the DSC curve.
[0017] The diacid residues of the polyester comprise at least 80 mole percent, relative to the total moles of diacid residues, of the residues of one or more of the following diacids: terephthalic acid, naphthalenedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid or isophthalic acid. Any of the various isomers of naphthalenedicarboxylic acid or mixtures of isomers can be used, but the 1, 4-, 1, 5-, 2, 6-and 2, 7-isomers are preferred. Cycloaliphatic dicarboxylic acids such as 1, 4-cyclohexanedicarboxylic acid may exist as pure cis or trans isomers, or as mixtures of cis and trans isomers. For example, the polyester can comprise 80 to 100 mole percent of diacid residues from terephthalic acid and 0 to 20 mole percent of diacid residues from isophthalic acid.
[0018] The polyester may also contain diol residues in the following proportions: 10 to 100 mole% of residues of 1, 4-cyclohexanedimethanol and 0 to 90 mole% of residues of one or more diols containing 2 to 20 carbon atoms. As used herein, the term "glycol" is synonymous with "diol" and refers to any dihydric alcohol. For example, the diol residues may further comprise 10 to 100 mole% of residues of 1, 4-cyclohexanedimethanol, and 0 to 90 mole% of residues of one or more diols selected from the group consisting of: ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, diethylene glycol, 1, 6-hexanediol, 1, 8-octanediol, 2, 4-trimethyl-1, 3-pentanediol, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, 1, 3-cyclohexanedimethanol, bisphenol a, and polyalkylene glycols. Other examples of diols which can be used in the polyesters of the invention are: triethylene glycol; polyethylene glycol; 2, 4-dimethyl-2-ethylhexane-1, 3-diol; 2, 2-dimethyl-1, 3-propanediol; 2-ethyl-2-butyl-1, 3-propanediol; 2-ethyl-2-isobutyl-1, 3-propanediol; 1, 3-butanediol; 1, 5-pentanediol; thiodiethanol; 1, 2-cyclohexanedimethanol; 1, 3-cyclohexanedimethanol; p-xylylene glycol; bisphenol S; or combinations of one or more of these diols. Cycloaliphatic diols such as 1, 3-and 1, 4-cyclohexanedimethanol may exist as their pure cis or trans isomers, as well as mixtures of cis and trans isomers. In another embodiment, the diol residues may comprise 10 to 100 mole% 1, 4-cyclohexanedimethanol residues and 0 to 90 mole% ethylene glycol residues. In yet another embodiment, the diol residues may comprise 20 to 80 mole% of the residues of 1, 4-cyclohexanedimethanol and 20 to 80 mole% of the residues of ethylene glycol. In yet another embodiment, the diol residues may comprise 20 to 70 mole% of residues of 1, 4-cyclohexanedimethanol and 80 to 30 mole% of residues of ethylene glycol. In yet another embodiment, the diol residues may comprise diacid residues comprising 20 to 65 mole percent of the residues of 1, 4-cyclohexanedimethanol and 95 to 100 mole percent of the residues of terephthalic acid.
[0019] The polyester may further comprise 0 to 20 mole% of residues of one or more modified diacids having 4 to 40 carbon atoms. Examples of useful modifying diacids include aliphatic dicarboxylic acids, cycloaliphatic dicarboxylic acids, aromatic dicarboxylic acids, or mixtures of two or more of these acids. Specific examples of modifying dicarboxylic acids include, but are not limited to, one or more of the following diacids: succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, azelaic acid, dimer acid, or sulfoisophthalic acid. Further examples of modified dicarboxylic acids are fumaric acid, maleic acid, itaconic acid, 1, 3-cyclohexanedicarboxylic acid, diglycolic acid, 2, 5-norbornanedicarboxylic acid, phthalic acid, diphenic acid, 4 '-oxydibenzoic acid and 4, 4' -sulfonyldibenzoic acid.
[0020] The polyester comprises 0.05 to 1 weight percent, relative to the total weight of the polyester, of one or more branching monomers comprising 3 or more carboxyl substituents, hydroxyl substituents, or a combination thereof. Examples of branching monomers include, but are not limited to, polyfunctional acids or diols such as 1, 2, 4-trimellitic acid, 1, 2, 4-trimellitic anhydride, pyromellitic dianhydride, trimethylolpropane, glycerol, pentaerythritol, citric acid, tartaric acid, 3-hydroxyglutaric acid, and the like. Preferably the branched monomer residues comprise 0.1 to 0.7 wt% of residues of one or more of the following compounds: 1, 2, 4-trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1, 2, 6-hexanetriol, pentaerythritol, trimethylolethane or 1, 3, 5-trimellitic acid. The branching monomer may be added to the polyester reaction mixture or blended with the polyester in concentrate form as described in U.S. patents 5,654,347 and 5,696,176.
[0021] In order to obtain an excellent rolling line speed, the intrinsic viscosity of the polyester of the invention is preferably 0.55-0.75 dL/g. Intrinsic viscosity, abbreviated herein as "i.v.", refers to the intrinsic viscosity measured at 25 ℃ with a solution containing 0.25g of polymer per 50ml of solvent consisting of 60 wt.% phenol and 40 wt.% tetrachloroethane. Other examples of I.V. values that the polyester composition can have are 0.55 to 0.70dL/g, 0.55 to 0.65dL/g, and 0.60 to 0.65 dL/g.
[0022]In addition to the polyester, the polyester composition described above contains an additive effective to prevent the polyester from sticking to the calender rolls. As used herein, the term "effective" means that the polyester passes freely between the calendering rolls without wrapping the rolls or creating overlapping polyester layers on the roll surfaces. The amount of the additive in the polyester resin composition is generally 0.1 to 10 wt% based on the total weight percent of the polyester composition. The optimum amount of additive to be used depends on factors well known in the art and depends on variations in equipment, materials, processing conditions and film thickness. Other examples of the amount of the additive are 0.1 to 5% by weight and 0.1 to 2% by weight. Examples of the additive of the present invention include fatty acid amides such as erucamide and stearamide; metal salts of organic acids such as calcium stearate and zinc stearate; fatty acids such as stearic acid, oleic acid and palmitic acid; a fatty acid salt; a fatty acid ester; hydrocarbon waxes such as paraffin wax, phosphoric acid ester, polyethylene wax and polypropylene wax; chemically modified polyolefin waxes; ester waxes, such as carnauba wax; glycerides, such as glycerol mono-or distearate; microcrystalline silicon dioxide; and acrylic acid copolymers (e.g., available from Rohm)&Paraloid of Haas®K175) In that respect The additives generally comprise one or more of the following compounds: erucylAmines and stearamides, calcium stearate, zinc stearate, stearic acid, montanic acid esters, montanic acid salts, oleic acid, palmitic acid, paraffin wax, polyethylene wax, polypropylene wax, carnauba wax, glycerol monostearate or glycerol distearate.
[0023] Another additive that can be used comprises (i) a fatty acid or a salt of a fatty acid having 18 or more carbon atoms and (ii) an ester wax comprising a fatty acid residue having 18 or more carbon atoms and an alcohol residue having 2 to 28 carbon atoms. The ratio of fatty acid or fatty acid salt to ester wax may be 1: 1 or higher. In this embodiment, another benefit obtained from the combination of fatty acid or fatty acid salt and ester wax in the above proportions is a haze value of less than 5% for the film or sheet. Additives having a fatty acid component of 18 or less carbon atoms are of lower molecular weight and thus become miscible with the polyester. Such miscible additives have less interfacial migration surface quality and therefore poor mold release, or higher haze. In another embodiment, the ratio of fatty acid or fatty acid salt to ester wax is 2: 1 or higher.
[0024] The fatty acid may comprise montanic acid, wherein the salt of the fatty acid may comprise one or more of the following salts: sodium salt of montanic acid, calcium salt of montanic acid, or lithium salt of montanic acid. The fatty acid residues of the ester wax may comprise montanic acid. The alcohol residue of the ester wax preferably contains 2 to 28 carbon atoms. Examples of the alcohol include montan alcohol, ethylene glycol, butylene glycol, glycerin, and pentaerythritol. The additive may also comprise an ester wax that has been partially saponified with a base, such as calcium hydroxide.
[0025] The polyesters of the present invention are readily prepared from suitable dicarboxylic acids, esters, anhydrides or salts; suitable diols or diol mixtures and branching monomers are prepared using typical polycondensation reaction conditions. They can be prepared in continuous, semi-continuous and batch modes of operation and can be used in a wide variety of reactors. Examples of suitable reactor types include, but are not limited to, stirred tank, continuous stirred tank, slurry, tubular, wiped film, falling film, or extrusion reactors. The term "continuous", as used herein, refers to a process in which the introduction of reactants and the withdrawal of products are performed simultaneously in an uninterrupted manner. By "continuous" is meant that the process is essentially or completely continuous in operation, as opposed to a batch process. "continuous" is not meant to interfere in any way with the normal interruption of process continuity due to, for example, start-up, reactor maintenance or scheduled shut-down cycles. The term "batch" process, as used herein, refers to a process that is: all reactants are added to the reactor and then processed according to a predetermined reaction profile without material being fed into or removed from the reactor. The term "semi-continuous" refers to a process in which: some of the reactants are added at the beginning of the process and the remainder are added continuously as the reaction progresses. Alternatively, a semi-continuous process may also include a process similar to a batch process: in which all reactants are added at the beginning of the process, but one or more products are continuously withdrawn as the reaction progresses. For economic reasons and to produce polymers with good color, it is preferred to operate the process in a continuous process, since the polyester will have a poor appearance if allowed to reside in the reactor at elevated temperatures for too long a period of time.
[0026]The polyesters of the invention are prepared by procedures well known to those skilled in the art. The reaction of the diol, dicarboxylic acid and branched monomer components may be carried out using conventional polyester polymerization conditions. For example, when the polyester is prepared by transesterification, i.e., from the ester form of the dicarboxylic acid component, the reaction process may comprise two steps. In the first step, the diol component and the dicarboxylic acid component, such as dimethyl terephthalate, are allowed to react at a pressure of 0.0kPa to 414kPa (60 lbs/inch)2And "psig") at a gauge pressure and at elevated temperature, typically 150 deg.c to 250 deg.c, for 0.5 to 8 hours. The transesterification reaction is preferably carried out at a temperature of between 180 ℃ and 230 ℃ for a period of time ranging from 1 to 4 hours, and preferably at a pressure ranging from 103kPa (15psig) to 276kPa (40psig) gauge. The reaction product is then heated at higher temperatures and reduced pressure to form a polyester and remove the diol, under conditions where the diol is very volatile and is removed from the system. This second, or polycondensation, step is carried out at a higher vacuum and generally at a temperature of 230 ℃ to 350 ℃, preferably 250 ℃ to 310 ℃, and very preferably 260 ℃ to 290 ℃ for 0.1 to 6 hours, or preferably 0.2 to 2 hours, until the polymer reaches the desired degree of polymerization, which is determined by the intrinsic viscosity. The polycondensation step may be at 53kPa (400 torr) to 0.013kPa (0.1 torr). Stirring and appropriate conditions are used in both stages to ensure adequate heat exchange and surface renewal of the reaction mixture. The reaction rates in both stages are increased by the use of suitable catalysts as follows: titanium alkoxide compounds, alkali metal hydroxides and alcoholates, organic carboxylates, alkyl tin compounds, metal oxides, and the like. A three stage manufacturing process similar to that described in U.S. patent 5,290,631 can also be used, particularly when fed with a mixed monomer of acid and ester.
[0027] In order to ensure that the reaction of the diol component and the dicarboxylic acid component proceeds completely by the transesterification reaction, it is sometimes preferable to use 1.05 to 2.5mol of the diol component to 1mol of the dicarboxylic acid component. However, it will be understood by those skilled in the art that the ratio of the diol component to the dicarboxylic acid component will generally depend on the design of the reactor in which the reaction is conducted.
[0028] In the case of the preparation of polyesters by the direct transesterification process, i.e.from the acid form of the dicarboxylic acid component, the polyesters are produced by reaction of the dicarboxylic acid or dicarboxylic acid mixture with the diol component or diol mixture component and the branching monomer component. The reaction is conducted at a pressure of from 7kPa (1psig) to 1379kPa (200psig), preferably less than 689kPa (100psig), to produce a low molecular weight polyester product having an average degree of polymerization of from 1.4 to 10. The temperature used during the direct transesterification reaction is generally from 180 ℃ to 280 ℃ and more preferably from 220 ℃ to 270 ℃. The low molecular weight polymer may then be polymerized by a polycondensation reaction.
[0029] In another embodiment, the present invention provides a polyester composition for calendering comprising:
(a) a polyester having a crystallization half time from the molten state of at least 30 minutes and an intrinsic viscosity of from 0.55 to 0.70dL/g, wherein the polyester is a random copolymer comprising:
(i) diacid residues comprising 90 mole%, relative to the total moles of diacid residues, of residues of one or more of the following acids: terephthalic acid, naphthalenedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid or isophthalic acid;
(ii) diol residues comprising 20 to 70 mole%, relative to the total moles of diol residues, of residues of one or more diols selected from the group consisting of: 1, 4-cyclohexanedimethanol, neopentyl glycol or diethylene glycol, and 30 to 80 mole% of the residues of one or more diols selected from the group consisting of: ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 8-octanediol, 2, 4-trimethyl-1, 3-pentanediol, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, 1, 3-cyclohexanedimethanol, bisphenol a, and polyalkylene glycol; and
(iii) a branched monomer residue comprising 0.05 to 0.7 wt.%, relative to the total weight of the polyester, of residues of one or more of the following compounds: 1, 2, 4-trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1, 2, 6-hexanetriol, pentaerythritol, trimethylolethane or 1, 3, 5-trimellitic acid; and
(b) 0.1 to 10% by weight, relative to the total weight of the polyester composition, of an additive effective to prevent sticking of said polyester to calendering rolls, wherein the additive comprises one or more of the following compounds: fatty acid amides, metal salts of organic acids, fatty acid salts, fatty acid esters, hydrocarbon waxes, ester waxes, phosphoric acid esters, chemically modified polyolefin waxes; glycerol esters, talc or acrylic copolymers.
Other examples of I.V. values that the polyester composition may have are 0.55 to 0.65dL/g and 0.60 to 0.65 dL/g. Any of the various isomers of naphthalenedicarboxylic acid or mixtures of isomers can also be used, but the 1, 4-, 1, 5-, 2, 6-and 2, 7-isomers are preferred. In addition, the 1, 4-cyclohexanedicarboxylic acid may be present as the pure cis or trans isomer or as a mixture of cis and trans isomers. The semi-crystallization time of the polyester being a random copolymer is at least 30 minutes.
[0030] Preferred additives comprise (i) a fatty acid or a salt of a fatty acid having 18 or more carbon atoms and (ii) an ester wax comprising a fatty acid residue having 18 or more carbon atoms and an alcohol residue having 2 to 28 carbon atoms. The ratio of fatty acid or fatty acid salt to the ester wax is 1: 1 or greater. In this embodiment, another benefit obtained from the combination of fatty acid or fatty acid salt and ester wax in the above proportions is a haze value of less than 5% for the film or sheet. In another embodiment, the ratio of fatty acid or fatty acid salt to ester wax is 2: 1 or greater. The fatty acid may comprise montanic acid, and the salt of the fatty acid may comprise one or more of a sodium salt of montanic acid, a calcium salt of montanic acid, and a lithium salt of montanic acid. The fatty acid residues of the ester wax may comprise montanic acid. Examples of the alcohol residue of the ester wax include residues of montanyl alcohol, ethylene glycol, butylene glycol, glycerin, and pentaerythritol. The additive may also comprise an ester wax that has been partially saponified with a base such as calcium hydroxide.
[0031] The polyester compositions of the present invention may also contain a plasticizer, although not exclusively. The presence of a plasticizer is advantageous for improving the flexibility and good mechanical properties of the calendered film or sheet. Plasticizers also help to lower the processing temperature of the polyester and will help to prevent the polyester composition from sticking to the calendering rolls. Plasticizers generally contain one or more aromatic rings. Preferred plasticizers are soluble in polyester as shown by dissolving a 5 mil (0.127mm) thick polyester film at 160 ℃ or less to produce a clear solution. More preferably, the plasticizer is soluble in the polyester as shown by dissolving a 5 mil (0.127mm) thick polyester film at 150 ℃ or less to produce a clear solution. The solubility of the plasticizer in the polyester can be determined as follows:
1. a length of 1/2 inch standard reference film was placed in the vial, 5 mil (0.127mm) thick, and approximately equal to the width of the vial.
2. The plasticizer was added to the vial until the film was completely submerged.
3. The vial with the film and plasticizer was placed on a shelf and observed after 1 hour and again after 4 hours. The appearance of the film and liquid was recorded.
4. After observation at room temperature, the vial was placed in a heating block and allowed to stand at 75 ℃ for 1 hour, and the appearance of the film and the liquid was observed.
5. Repeat step 4 at the following temperatures (. degree. C.): 100. 140, 150 and 160.
[0032] Examples of plasticizers and their solubilities determined by the above tests are listed in table 1. Values of 4 or greater than 4 at the temperatures indicated indicate that the plasticizer is a candidate for use in the present invention.
TABLE 1 solubility of plasticizers
| Temperature (. degree.C.) | 23 | 75 | 100 | 140 | 150 | 160 |
| Adipic acid derivatives | ||||||
| Dioctyl adipate | 1 | 1 | 1 | 1 | 2 | 2 |
| Bis- (2-ethylhexyl adipate) | 1 | 1 | 1 | 1 | 2 | 2 |
| Adipic acid di (n-heptyl, nonyl) | 1 | 1 | 1 | 1 | 2 | 2 |
| Adipic acid diisobutyl ester | 1 | 3 | 3 | 3 | 3 | 4 |
| Diisodecyl adipate | 1 | 1 | 1 | 1 | 1 | 1 |
| Dinonyl adipate | 1 | 1 | 1 | 1 | 1 | 2 |
| Adipic acid di (tridecyl) ester | 1 | 1 | 1 | 1 | 1 | 1 |
| Azelaic acid derivatives | ||||||
| Bis- (2-ethylhexyl azelate) | 1 | 1 | 1 | 1 | 2 | 2 |
| Azelaic acid diisodecyl ester | 1 | 1 | 1 | 1 | 1 | 1 |
| Diisooctyl azelate | 1 | 1 | 1 | 1 | 2 | 2 |
| Azelaic acid dimethyl ester | 3 | 4 | 4 | 4 | 4 | 6 |
| Azelaic acid di-n-hexyl ester | 1 | 1 | 2 | 2 | 3 | 3 |
| Benzoic acid derivatives | ||||||
| Diethylene glycol dibenzoate (DEGDB) | 4 | 4 | 4 | 6 | 6 | 6 |
| Dipropylene glycol dibenzoate | 3 | 3 | 4 | 4 | 4 | 6 |
| Propylene glycol dibenzoate | 1 | 3 | 4 | 6 | 6 | 6 |
| Diphenyl formic acid polyethylene glycol 200 ester | 4 | 4 | 4 | 4 | 6 | 6 |
| Dichlorobenzoic acid neopentyl glycol ester | 0 | 3 | 3 | 3 | 4 | 6 |
| Citric acid derivatives | ||||||
| Citric acid acetyl tri-n-butyl ester | 1 | 1 | 1 | 2 | 3 | 3 |
| Acetyl triethyl citrate | 1 | 2 | 2 | 2 | 3 | 3 |
| Citric acid tri-n-butyl ester | 1 | 2 | 3 | 3 | 3 | 3 |
| Citric acid triethyl ester | 3 | 3 | 3 | 3 | 3 | 3 |
| Dimer acid derivatives | ||||||
| Bis (dimer acid 2-hydroxyethyl ester) | 1 | 1 | 1 | 1 | 2 | 3 |
| Epoxy derivatives |
| Temperature (. degree.C.) | 23 | 75 | 100 | 140 | 150 | 160 |
| Epoxidized linseed oil | 1 | 2 | 2 | 2 | 3 | 3 |
| Epoxidized soybean oil | 1 | 1 | 1 | 1 | 1 | 2 |
| 2-ethylhexyl epoxy resinate | 1 | 1 | 1 | 1 | 3 | 3 |
| Fumaric acid derivatives | ||||||
| Dibutyl fumarate | 2 | 2 | 3 | 3 | 3 | 3 |
| Glycerol derivatives | ||||||
| Tribenzoic acid glyceride | 0 | 0 | 6 | 6 | 6 | 6 |
| Glycerol triacetate | 2 | 3 | 3 | 3 | 3 | 4 |
| Diacetic acid monolaurin | 1 | 2 | 2 | 2 | 2 | 4 |
| Isobutyrate derivatives | ||||||
| 2, 2, 4-trimethyl-1, 3-pentanediol diisobutyrate | 1 | 1 | 1 | 1 | 3 | 3 |
| Texanol diisobutyrate ester | 1 | 2 | 2 | 2 | 2 | 4 |
| Isophthalic acid ester derivatives | ||||||
| Isophthalic acid dimethyl ester | 0 | 5 | 5 | 6 | 6 | 6 |
| Isophthalic acid diphenyl ester | 0 | 0 | 0 | 0 | 0 | 0 |
| Di-n-butyl isophthalate | 2 | 3 | 3 | 3 | 3 | 3 |
| Lauric acid derivative | ||||||
| Lauric acid methyl ester | 1 | 2 | 3 | 3 | 3 | 3 |
| Linoleic acid derivatives | ||||||
| Linoleic acid methyl ester, 75% | 1 | 1 | 2 | 3 | 3 | 3 |
| Maleic acid derivatives | ||||||
| Maleic acid di (2-ethylhexyl) ester | 1 | 1 | 2 | 3 | 3 | 3 |
| Maleic acid di-n-butyl ester | 2 | 3 | 3 | 3 | 3 | 3 |
| Benzoic acid esters | ||||||
| Trioctyl 1, 2, 4-trimellitate | 1 | 1 | 1 | 1 | 1 | 1 |
| 1, 2, 4-Triisodecyl trimesate | 1 | 1 | 1 | 1 | 1 | 1 |
| 1, 2, 4-Trimellitate tri (n-octyl, n-decyl) | 1 | 1 | 1 | 1 | 1 | 1 |
| 1, 2, 4-Triisononyl trimellitate | 1 | 1 | 1 | 1 | 1 | 1 |
| Myristic acid derivatives | ||||||
| Myristic acid isopropyl ester | 1 | 1 | 1 | 2 | 3 | 3 |
| Temperature (. degree.C.) | 23 | 75 | 100 | 140 | 150 | 160 |
| Oleic acid derivatives | ||||||
| Oleic acid butyl ester | 1 | 1 | 1 | 2 | 3 | 3 |
| Glyceryl monooleate | 0 | 1 | 1 | 1 | 3 | 3 |
| Triolein | 1 | 1 | 1 | 1 | 2 | 2 |
| Oleic acid methyl ester | 1 | 1 | 2 | 2 | 3 | 3 |
| Oleic acid n-propyl ester | 1 | 1 | 1 | 2 | 3 | 3 |
| Tetrahydrofurfuryl oleate | 1 | 1 | 1 | 2 | 3 | 3 |
| Palmitic acid derivatives | ||||||
| Palmitic acid isopropyl ester | 1 | 1 | 1 | 1 | 2 | 3 |
| Palmitic acid methyl ester | 0 | 1 | 1 | 2 | 3 | 3 |
| Paraffin derivatives | ||||||
| Chlorinated paraffin, 41% Cl | 1 | 1 | 2 | 2 | 2 | 3 |
| Chlorinated paraffin, 50% Cl | 1 | 2 | 3 | 3 | 3 | 3 |
| Chlorinated paraffin, 60% Cl | 1 | 5 | 6 | 6 | 6 | 6 |
| Chlorinated paraffin, 70% Cl | 0 | 0 | 0 | 0 | 0 | 0 |
| Phosphoric acid derivatives | ||||||
| Phosphoric acid 2-ethylhexyl diphenyl ester | 2 | 3 | 3 | 3 | 4 | 4 |
| Isodecyl diphenyl phosphate | 1 | 2 | 3 | 3 | 3 | 3 |
| Tert-butylphenyl diphenyl phosphate | 1 | 3 | 3 | 4 | 6 | 6 |
| Resorcinol bis (diphenyl phosphate) (RDP) | ||||||
| 100％RDP | 1 | 1 | 1 | 3 | 3 | 3 |
| Blend of 75% RDP, 25% DEGDB (by weight) | 1 | 2 | 2 | 4 | 4 | 5 |
| Blend of 50% RDP, 50% DEGDB (by weight) | 1 | 2 | 5 | 6 | 6 | 6 |
| Blend of 25% RDP, 75% DEGDB (by weight) | 1 | 3 | 3 | 6 | 6 | 6 |
| Tributoxyethyl phosphate | 1 | 2 | 3 | 4 | 4 | 4 |
| Phosphoric acid tributyl ester | 2 | 3 | 3 | 3 | 3 | 3 |
| Tricresyl phosphate | 1 | 3 | 3 | 4 | 6 | 6 |
| Phosphoric acid triphenyl ester | 0 | 4 | 4 | 6 | 6 | 6 |
| Phthalic acid derivatives | ||||||
| Butylbenzyl phthalate | 2 | 3 | 3 | 6 | 6 | 6 |
| Texanol benzyl phthalate | 2 | 2 | 2 | 2 | 2 | 4 |
| Temperature (. degree.C.) | 23 | 75 | 100 | 140 | 150 | 160 |
| Phthalic acid butyl octyl ester | 1 | 1 | 2 | 2 | 3 | 3 |
| Dioctyl phthalate | 1 | 1 | 1 | 1 | 2 | 2 |
| Phthalic acid dicyclohexyl ester | 0 | 1 | 2 | 2 | 4 | 5 |
| Phthalic acid di- (2-ethylhexyl) ester | 1 | 1 | 1 | 2 | 3 | 3 |
| Phthalic acid diethyl ester | 4 | 4 | 4 | 6 | 6 | 6 |
| Dihexyl phthalate | 1 | 2 | 3 | 3 | 3 | 3 |
| Phthalic acid diisobutyl ester | 1 | 3 | 3 | 3 | 3 | 5 |
| Diisodecyl phthalate | 1 | 1 | 1 | 1 | 2 | 2 |
| Diisoheptyl phthalate | 1 | 1 | 2 | 3 | 3 | 3 |
| Diisononyl phthalate | 1 | 1 | 1 | 1 | 2 | 3 |
| Diisooctyl phthalate | 1 | 1 | 2 | 2 | 3 | 3 |
| Phthalic acid dimethyl ester | 1 | 5 | 6 | 6 | 6 | 6 |
| Phthalic acid di (tridecyl) ester | 1 | 1 | 1 | 1 | 2 | 3 |
| Di (undecyl) phthalate | 1 | 1 | 1 | 2 | 2 | 2 |
| Ricinoleic acid derivatives | ||||||
| Ricinoleic acid butyl ester | 1 | 1 | 2 | 3 | 3 | 3 |
| Ricinoleic acid glycerol tri (acetyl) ester | 1 | 1 | 1 | 2 | 1 | 1 |
| Ricinoleic acid methyl acetyl ester | 1 | 1 | 2 | 3 | 3 | 3 |
| Ricinoleic acid methyl ester | 1 | 2 | 3 | 3 | 3 | 4 |
| Ricinoleic acid n-butyl acetyl ester | 1 | 1 | 1 | 2 | 3 | 3 |
| Ricinoleic acid propylene glycol ester | 1 | 1 | 3 | 3 | 4 | 4 |
| Sebacic acid derivatives | ||||||
| Dibutyl sebacate | 1 | 2 | 3 | 3 | 3 | 3 |
| Sebacic acid bis (2-ethylhexyl) ester | 1 | 1 | 1 | 2 | 2 | 3 |
| Sebacic acid dimethyl ester | 0 | 4 | 4 | 6 | 6 | 6 |
| Stearic acid derivatives | ||||||
| Ethylene glycol monostearate | 0 | 1 | 2 | 3 | 3 | 3 |
| Glyceryl monostearate | 0 | 0 | 1 | 2 | 2 | 2 |
| Isostearic acid isopropyl ester | 3 | 3 | 3 | 6 | 6 | 6 |
| Stearic acid methyl ester | 0 | 1 | 2 | 2 | 2 | 3 |
| Temperature (. degree.C.) | 23 | 75 | 100 | 140 | 150 | 160 |
| Stearic acid n-butyl ester | 1 | 1 | 2 | 3 | 3 | 3 |
| Propylene glycol monostearate | 0 | 1 | 1 | 2 | 2 | 3 |
| Derivatives of succinic acid | ||||||
| Succinic acid diethyl ester | 3 | 3 | 4 | 5 | 6 | 6 |
| Sulfonic acid derivatives | ||||||
| N-ethyl, o, p-toluenesulfonamide | 2 | 5 | 6 | 6 | 6 | 6 |
| Ortho, para-toluenesulfonamides | 0 | 0 | 0 | 6 | 6 | 6 |
Key words:
0 ═ is solid at this temperature
The 1 ═ plasticizer is liquid, but the film is unchanged
2-film already started to fog
3 ═ film swollen
The film has begun to fragment and/or the liquid has become cloudy
5-no longer a film, the liquid was turbid
6 ═ liquid transparency
[0033]Assays similar to those described above are described in J.Kern search and Joseph R.Darby, The Technology of Plasticizers, published by Society of Plastic Engineers/Wiley and Sons, New York, 1982, pp 136-137. In this test, a polymer is placed in a drop of plasticizer on a microscope hot stage. If the polymer disappears, it is soluble. According to table 1, the plasticizers which dissolve the polyesters of the invention very effectively have a solubility of more than 4 and can also be classified according to their solubility parameters. The evolution of the solubility parameter or cohesive energy density of a plasticizer can be calculated using the method described by Coleman et al in Polymer 31, 1187 (1990). Most preferably, the plasticizer has a solubility parameter (delta) of about 9.5 to 13.0 cal0.5cm-1.5Within the range. It is generally understood that the solubility parameter of the plasticizer should be within 1.5 units of the solubility parameter of the polyester. The data in Table 2 illustrate that plasticizers having a solubility parameter within this range are capable of dissolving polyester, while plasticizers having a solubility parameter outside this range are less effective.
TABLE 2
| Plasticizer | Delta (card)0.5cm-1.5) | Solubility at 160 ℃ is taken from Table 1 |
| Diacetic acid monolaurin | 8.1 | 4 |
| Texanol diisobutyrate ester | 8.4 | 4 |
| Adipic acid di-2-ethylhexyl ester | 8.5 | 2 |
| Trioctyl 1, 2, 4-trimellitate | 8.8 | 1 |
| Di-2-ethylhexyl phthalate | 8.9 | 2 |
| Texanol benzyl phthalate | 9.5 | 4 |
| Dichlorobenzoic acid neopentyl glycol ester | 9.8 | 6 |
| Dipropylene glycol dibenzoate | 10.0 | 6 |
| Butylbenzyl phthalate | 10.1 | 6 |
| Propylene glycol dibenzoate | 10.3 | 6 |
| Diethylene glycol dibenzoate | 10.3 | 6 |
| Tribenzoic acid glyceride | 10.6 | 6 |
[0034] Generally, higher molecular weight plasticizers are preferred to prevent smoking and loss of plasticizer during calendering. The preferred range of plasticizer content will depend on the properties of the base polyester and the plasticizer. In particular, as the Tg of the polyester decreases as predicted by the well-known Fox equation (t.g. Fox, fill.am.phys.soc., time 1, 123(1956)), the amount of plasticizer required to obtain a satisfactorily calendered polyester composition is also reduced. Generally, the plasticizer comprises 5 to 50 weight percent of the polyester composition, based on the total weight of the polyester composition. Other examples of plasticizer content are 10 to 40 wt%, 15 to 40 wt% and 15 to 30 wt% of the polyester composition.
[0035] Examples of plasticizers which can be used according to the invention are esters comprising the following components: (i) an acid residue comprising the residue of one or more of the following acids: phthalic acid, adipic acid, 1, 2, 4-trimellitic acid, benzoic acid, azelaic acid, terephthalic acid, isophthalic acid, butyric acid, glutaric acid, citric acid, or phosphoric acid; and (ii) an alcohol residue comprising the residue of one or more aliphatic, cycloaliphatic or aromatic alcohols containing up to 20 carbon atoms. Further, non-limiting examples of alcohol residues of the plasticizer include residues of the following alcohols: methanol, ethanol, propanol, isopropanol, butanol, isobutanol, stearyl alcohol, lauryl alcohol, phenol, benzyl alcohol, hydroquinone, catechol, resorcinol, ethylene glycol, neopentyl glycol, 1, 4-cyclohexanedimethanol, and diethylene glycol. The plasticizer may also comprise one or more benzoates, phthalates, phosphates, or isophthalates. In another embodiment, the plasticizer comprises diethylene glycol dibenzoate, abbreviated herein as "DEGDB".
[0036] The polyester composition may also comprise a phosphorus-containing flame retardant, although the presence of a flame retardant is not critical to the invention. The phosphorous containing flame retardant should be miscible with the polyester or plasticized polyester. The term "miscible", as used herein, is understood to mean that the flame retardant and the plasticized polyester will be mixed together to form a stable mixture that will not separate into multiple phases under the processing conditions or the use conditions. Thus, the term "miscible" is intended to include both "miscible" mixtures in which the flame retardant and the plasticized polyester are capable of forming true solutions, and "compatible" mixtures in which the mixture of flame retardant and plasticized polyester do not form true solutions but merely form stable blends. Preferably, the phosphorus-containing compound is a non-halogenated organic compound, for example, a phosphite containing organic substituents. The flame retardant may comprise a wide variety of phosphorus compounds known in the art, for example, phosphines, phosphites, phosphinites, phosphonites, phosphinites, phosphonates, phosphine oxides, and phosphates. Examples of phosphorus-containing flame retardants include tributyl phosphate, triethyl phosphate, tributoxyethyl phosphate, t-butylphenyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, ethyl dimethyl phosphate, isodecyl diphenyl phosphate, trilauryl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, t-butylphenyl diphenyl phosphate, resorcinol bis (diphenyl phosphate), tribenzyl phosphate, phenylethyl phosphate, trimethyl thiocarbonyl phosphate, phenylethyl thiocarbonyl phosphate, dimethyl methylphosphonate, diethyl pentylphosphonate, dilauryl methylphosphonate, diphenyl methylphosphonate, dibenzyl methylphosphonate, diphenyl tolylphosphonate, dimethyl methylthiocarbonylphosphonate, phenyl biphenylphosphinate, benzyl biphenylphosphinate, methyl biphenylphosphinate, dimethyl biphenylphosphinate, and dimethyl biphenylphosphinate, Trimethylphosphine oxide, triphenylphosphine oxide, tribenzylphosphine oxide, 4-methylbiphenylphosphine oxide, triethyl phosphite, tributyl phosphite, trilauryl phosphite, triphenyl phosphite, tribenzyl phosphite, phenyl diethyl phosphite, phenyl dimethyl phosphite, benzyl dimethyl phosphite, dimethyl methyl phosphite, diethyl amyl phosphonite, diphenyl methyl phosphonite, dibenzyl methyl phosphonite, dimethyl cresyl phosphonite, methyl dimethyl phosphinite, methyl diethylphosphinate, phenyl biphenylphosphinate, methyl biphenylphosphinate, benzyl biphenylphosphinate, triphenylphosphine, tribenzylphosphine, and methylbiphenylphosphine.
[0037] The term "phosphorous acid", as used in describing the phosphorus-containing flame retardants of the present invention, includes inorganic acids, such as phosphoric acid, acids with direct carbon-phosphorus bonds, such as phosphonic and phosphinic acids, and partially esterified phosphorous acids containing at least one acid group which has not been esterified, such as the mono-and di-basic esters of phosphoric acid, and the like. Typical phosphorous acids useful in the present invention include, but are not limited to, dibenzyl phosphoric acid, dibutyl phosphoric acid, bis (2-ethylhexyl) phosphoric acid, biphenyl phosphoric acid, methylphenyl phosphoric acid, phenyl benzyl phosphoric acid, hexyl phosphonic acid, phenyl phosphonic acid, tolyl phosphonic acid, benzyl phosphonic acid, 2-phenylethyl phosphonic acid, methyl hexyl phosphinic acid, biphenyl phosphinic acid, phenyl naphthyl phosphinic acid, dibenzyl phosphinic acid, methylphenyl phosphinic acid, phenyl phosphinic acid, tolyl phosphorous acid, benzyl phosphinic acid, butyl phosphoric acid, 2-ethylhexyl phosphoric acid, phenyl phosphoric acid, tolyl phosphoric acid, benzyl phosphoric acid, phenyl phosphorous acid, toluene phosphorous acid, benzyl phosphorous acid, biphenyl phosphorous acid, phenyl benzyl phosphorous acid, dibenzyl phosphorous acid, methylphenyl phosphorous acid, phenyl phenylphosphonic acid, tolyl methylphosphonic acid, ethyl benzyl phosphonic acid, biphenyl phosphorous acid, toluene phosphorous acid, methylethylphosphonous acid, methylphenylphosphonic acid and phenylphenylphosphonous acid. The flame retardant typically comprises one or more mono-, di-, or tri-esters of phosphoric acid. In another embodiment, the flame retardant comprises resorcinol bis (diphenyl phosphate), abbreviated herein as "RDP".
[0038] The flame retardant may be added to the polyester composition at a concentration of 5 to 40% by weight based on the total weight of the polyester composition. Other examples of flame retardants are used in amounts of 7 to 35 wt.%, 10 to 30 wt.% and 10 to 25 wt.%. The flame retardant polyester compositions of the present invention generally give a rate of V2 or greater in the UL94 burn test. In addition, our flame retardant polyester composition has a burn rate of 0 in federal automotive safety standard 302 (commonly referred to as FMVSS 302).
[0039] The phosphorus-containing flame retardant may also act as a plasticizer for the polyester. In this embodiment, the flame retardant may replace some or all of the plasticizer component in the polyester composition, depending on the efficiency of the flame retardant as a plasticizer. Generally, when using plasticized flame retardants, to achieve the desired burn rate or flame retardancy of a calendered film or sheet, the amount of flame retardant is first determined and then adjusted to obtain the desired Tg of the film or sheet.
[0040]The polyesters of the present invention may also be used with oxidative stabilizers to prevent oxidative degradation of molten or semi-molten materials during processing on rolls. Such stabilizers include esters, such as distearyl or dilauryl thiodiacrylate; phenolic stabilisers, e.g. IRGANOX from Ciba-Geigy AG®1010. ETHANOX, available from Ethyl Corporation®330 and butylated hydroxytoluene; and phosphorus-containing stabilizers, such as IRGAFOS available from Ciba-Geigy AG®And WESTON available from GE Specialty Chemicals®A stabilizer. Such stabilizers may be used alone or in combination.
[0041]Agents such as sulfoisophthalic acid may also be used to increase the melt strength of the polyester to a desired level. In addition, the polyester composition may contain dyes, pigments, fillers, delustering agents, antiblocking agents, antistatic agents, blowing agents, short fibers, glass, impact modifiers, carbon black, talc, TiO, as required2And the like. Colorants, sometimes referred to as toners, may be added to impart the desired neutral color to the polyester and calendered productsHarmonious and/or bright.
[0042] Many of the components of the polyester composition, such as flame retardants, mold release additives, plasticizers, toners, and the like, can be blended in a batch process, a semi-continuous process, or a continuous process. The small batches are readily prepared in any high intensity mixing equipment known to those skilled in the art, such as a Banbury mixer, prior to calendering. The components may also be blended in solution in a suitable solvent. The melt blending process involves blending the polyester, plasticizer, flame retardant, additives, and any other non-polymeric components at a temperature sufficient to melt the polyester. The blend may be cooled and shaped for further use, or the melt blend may also be calendered directly from the melt blend into a film or sheet. The term "melt", as used herein, includes, but is not limited to, softening only polyester. For melt Mixing methods generally known in the polymer art, see "Mixing and compounding of Polymers" (I.Manas-ZLOCzower & Z.Tadmor editors, Carl Hanser Verlag publishers, 1994, New York, N.Y.). When it is desired to color the sheet or film, pigments or colorants may be included in the polyester mixture during the reaction of the diol and dicarboxylic acid, or they may also be melt blended with the preformed polyester. The preferred method of adding the colorant is to copolymerize or add the colorant to the polyester with a colorant containing a thermally stable organic coloring compound having a reactive group to improve the color tone thereof. For example, colorants, such as dyes having reactive hydroxyl and/or carboxyl groups, including, but not limited to, blue and red substituted anthraquinones, may be copolymerized into the polymer chain. When dyes are used as colorants, they may be added to the polyester reaction process after transesterification or direct esterification.
[0043] Our invention also includes a process for producing a film or sheet comprising calendering a polyester composition comprising:
(a) a polyester having a crystallization half time from the molten state of at least 30 minutes and an intrinsic viscosity of from 0.55 to 0.75dL/g, wherein the polyester is a random copolymer comprising:
(i) diacid residues comprising at least 80 mole percent, relative to the total moles of diacid residues, of residues of one or more of the following acids: terephthalic acid, naphthalenedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid or isophthalic acid;
(ii) diol residues comprising 10 to 100 mole% of residues of 1, 4-cyclohexanedimethanol, and 0 to 90 mole% of residues of one or more diols selected from the group consisting of: ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, diethylene glycol, 1, 6-hexanediol, 1, 8-octanediol, 2, 4-trimethyl-1, 3-pentanediol, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, 1, 3-cyclohexanedimethanol, bisphenol a, and polyalkylene glycol; and
(iii) a branched monomer residue comprising 0.05 to 1 weight percent, relative to the total weight of the polyester, of one or more monomers comprising 3 or more carboxyl substituents, hydroxyl substituents, or a combination thereof; and
(b) an additive effective in preventing polyester from sticking to calender rolls.
Any of the various isomers of naphthalenedicarboxylic acid or mixtures of isomers may be used, but the 1, 4-, 1, 5-, 2, 6-and 2, 7-isomers are preferred. In addition, the 1, 4-cyclohexanedicarboxylic acid may be present as the pure cis or trans isomer or as a mixture of cis and trans isomers. Other examples of diols, modifying diacids, branching monomers, plasticizers and flame retardants have been described above for other embodiments of the polyester compositions of the present invention. Other examples of I.V. values that the polyester may have are 0.55 to 0.70dL/g, 0.55 to 0.65dL/g, and 0.60 to 0.65 dL/g.
[0044] The diol residues may comprise 10 to 100 mole% of residues of 1, 4-cyclohexanedimethanol and 0 to 90 mole% of residues of ethylene glycol. In another embodiment, the diol residues may comprise 20 to 80 mole% of the residues of 1, 4-cyclohexanedimethanol and 20 to 80 mole% of the residues of ethylene glycol. In yet another embodiment, the diol residues may comprise 20 to 65 mole% 1, 4-cyclohexanedimethanol residues and the dicarboxylic acid residues may comprise 95 to 100 mole% terephthalic acid residues. In addition, the polyester may further comprise from 0 to 20 mole% of the residues of one or more modified diacids having from 4 to 40 carbon atoms, as described above for the polyester composition of the invention. Preferred modifying dicarboxylic acids include, but are not limited to, one or more of the following diacids: one or more of succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, azelaic acid, dimer acid, or sulfoisophthalic acid. The polyester preferably comprises residues of branching monomers comprising 0.1 to 0.7 wt% of one or more of the following compounds: 1, 2, 4-trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1, 2, 6-hexanetriol, pentaerythritol, trimethylolethane or 1, 3, 5-trimellitic acid.
[0045] Preferred additives comprise from 0.1 to 10% by weight, relative to the total weight of the polyester composition, of one or more of the following compounds: fatty acid amides, metal salts of organic acids, fatty acid esters, hydrocarbon waxes, phosphate esters, chemically modified polyolefin waxes, glycerol esters, talc, or acrylic copolymers. Other examples of additives to prevent sticking of the polyester to the calendering rolls include one or more of the following compounds: erucamide, stearamide, calcium stearate, zinc stearate, stearic acid, montanic acid esters, montanic acid salts, oleic acid, palmitic acid, paraffin wax, polyethylene wax, polypropylene wax, carnauba wax, glyceryl monostearate or glyceryl distearate.
[0046] As previously mentioned, the polyester composition may also contain plasticizers and flame retardants as needed and appropriate for the intended application of the film. Preferred plasticizers are soluble in polyester as shown by dissolving a 5 mil (0.127mm) thick polyester film at 160 ℃ or less to produce a clear solution. In another embodiment, the preferred plasticizer is soluble in polyester, as shown by dissolving a 5 mil (0.127mm) thick polyester film at 150 ℃ or less to produce a clear solution. More preferred plasticizers contain one or more aromatic rings and more preferably contain one or more benzoates, phthalates, or isophthalates, as shown in table 1. Examples of plasticizers include, but are not limited to, neopentyl glycol dibenzoate, diethylene glycol dibenzoate, butyl benzyl phthalate, and texanol benzyl phthalate. Generally, the plasticizer comprises 5 to 50 weight percent of the polyester composition, based on the total weight of the polyester composition. Other examples of plasticizer content are 10 to 40 wt%, 15 to 40 wt% and 15 to 30 wt% of the polyester composition. The most preferred plasticizer is diethylene glycol dibenzoate.
[0047] The concentration of the flame retardant added to the polyester composition may be 5 to 40% by weight based on the total weight of the polyester composition. Other examples of flame retardants are used in amounts of 7 to 35 wt.%, 10 to 30 wt.%, and 10 to 25 wt.%. Preferably the flame retardant comprises one or more mono-, di-or triesters of phosphoric acid. The phosphorus-containing flame retardant may also function as a polyester plasticizer. In another embodiment, the plasticizer comprises diethylene glycol dibenzoate and the flame retardant comprises resorcinol bis (diphenyl phosphate). Flame retardant films or sheets generally give V2 or greater in the UL94 flame test. In addition, our flame retardant film or sheet has a burn rate of 0 as set forth in federal automotive safety standard 302 (commonly referred to as FMVSS 302).
[0048] The polyester composition may be calendered using conventional calendering processes and equipment. In the process of the present invention, the polyester composition may be in molten, granular or powder form and passed through a compression nip between at least 2 calendering rolls having a temperature of from 100 ℃ to 200 ℃. Generally, polyesters are blended with plasticizers, flame retardants, additives and other components. The mixed components are plasticized in a kneading or extruding machine. The dry powder is fused into a homogeneous melt by heat, shear and pressure. The extruder feeds the melt in a continuous process to the top of the calendering section of the calendering line between the first and second heated calender rolls. Typically 4 rolls are used to form 3 nips. For example, the rollers may be configured in an "L" "shape, an inverted" L "shape, or a" Z "configuration. The roll dimensions were varied to accommodate different film widths. The rolls are independently temperature and speed controlled. The material advances through the nip between the first two rolls, called the feed nip. The two rolls are counter-rotating to facilitate spreading of the material across the width of the rolls. The material meanders between the first and second, second and third, third and fourth rollers, etc. The gaps between the rolls decrease in sequence with the rolls, causing the material to progressively thin between the sets of rolls as it advances. Thus, the film or sheet resulting from passing the polyester composition through the compression nip between heated rolls has a uniform thickness. In fact, the polyester composition is compressed between the nips of the separating rollers. Each successive nip between the calender rolls reduces the film thickness until the final film or sheet size is obtained.
[0049]Typical processing temperatures for the rolls are generally from 80 ℃ to 220 ℃, preferably from 100 ℃ to 200 ℃, more preferably from 130 ℃ to 180 ℃. For certain hydrolytically unstable polyesters, it is desirable to pre-dry the polyester resin composition or to vent excess moisture during processing to prevent degradation of the polymer by hydrolysis. After passing through the calendering station, the material moves through another set of rollers where it is stretched and gradually cooled to form a film or sheet. The material may also be embossed or annealed before cooling. The cooled material is then wound onto a main roll. A general description of the calendering process is disclosed in Jim Butschli, Packaging World, p.26-28, June 1997 and W.V.Titow, PVCTechnology, 4thEdition, pp803 to 848, (1984), Elsevier Publishing Co.
[0050] Thus, our invention provides a film or sheet made by a calendering process comprising:
(a) a polyester having a crystallization half time from the molten state of at least 30 minutes and an intrinsic viscosity of from 0.55 to 0.70dL/g, wherein the polyester is a random copolymer comprising:
(i) diacid residues comprising at least 90 mole%, relative to the total moles of diacid residues, of residues of one or more of the following acids: terephthalic acid, naphthalenedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid or isophthalic acid;
(ii) diol residues comprising 10 to 100 mole% of residues of 1, 4-cyclohexanedimethanol, and 0 to 90 mole% of residues of one or more diols selected from the group consisting of: ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 8-octanediol, 2, 4-trimethyl-1, 3-pentanediol, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, 1, 3-cyclohexanedimethanol, bisphenol a, and polyalkylene glycol; and
(iii) a branched monomer residue comprising 0.05 to 0.7 wt.%, relative to the total weight of the polyester, of the residue of one or more of the following compounds: 1, 2, 4-trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1, 2, 6-hexanetriol, pentaerythritol, trimethylolethane or 1, 3, 5-trimellitic acid; and
(b) 0.1 to 10 wt.%, relative to the total weight of the polyester composition, of an additive effective to prevent sticking of the polyester to the calendering rolls, wherein the additive comprises one or more of the following compounds: fatty acid amides, metal salts of organic acids, fatty acid salts, fatty acid esters, hydrocarbon waxes, ester waxes, phosphoric acid esters, chemically modified polyolefin waxes; glycerol esters, talc, or acrylic copolymers.
The film or sheet may also include the various embodiments, concentration ranges, and combinations of diols, modified diacids, branching monomers, plasticizers, and flame retardants described above for the polyester compositions and calendering methods of the present invention. The invention is further illustrated and described by the following examples.
Examples
[0051] Examples 1 to 5. Calendering of unplasticized polyester. Collin twin roll machine was used to calender 5 kinds of pelletized PETG, branched and unbranched, containing 31 mol% 1, 4-cyclohexanedimethanol, from the molten state for a crystallization half time > 1000 minutes, which was instrumented to measure bearing pressure, material temperature, rotational resistance. The i.v. and branching monomer amounts for each sample are shown in table 3. 1, 2, 4-trimellitic anhydride is used as a branching monomer. The pellets coated with 0.75 wt% montan wax mold release additive were fed directly to heated rolls and processed into a melt. The set temperature of the processing roller is 145-175 ℃. Each sample was rolled at a roll speed of 5 to 20rpm to determine the i.v. and the effect of the branching monomer on the line speed of the rolling as indicated by bearing pressure (i.e. the pressure exerted by the melt separating the rolls as it extrudes into the gap between the rolls), roll drag (i.e. the torque required to rotate the rolls) and material temperature (a measure of the temperature of the melt as it mixes before entering the gap). The results are shown in tables 4 to 7.
TABLE 3
Unplasticized polyester compositions for use in calendering experiments
| Examples | Semi-crystallization time (min) | I.V.(dL/g) | Mold release additive (% by weight) | Branched monomer (% by weight) |
| 1 | ＞1000 | 0.76 | 0.75 | 0 |
| 2 | ＞1000 | 0.76 | 0.75 | 0 |
| 3 | ＞1000 | 0.76 | 0.75 | 0.18 |
| 4 | ＞1000 | 0.65 | 0.75 | 0 |
| 5 | ＞1000 | 0.65 | 0.75 | 0.20 |
TABLE 4
Influence of roll speed on Total roll drag at a roll gap of 0.2mm
Unplasticized composition
| Examples | 1 | 2 | 3 | 4 | 5 |
| Roll temperature, deg.C | 170 | 170 | 175 | 160 | 170 |
| Speed of the roller | Total resistance roll (Nm) | ||||
| 5RPM | 337 | 331 | 440 | 265 | 252 |
| 10RPM | 431 | 396 | 406 | 337 | 313 |
| 15RPM | 471 | 454 | 425 | 369 | 359 |
| 20RPM | 487 | 481 | 451 | 400 | 378 |
[0052] As shown by the data in table 4, the presence of the branching monomer reduced the roll resistance at higher calender roll speeds. Lower i.v. also reduces roll resistance. While the combination of lower i.v. and branched monomer resulted in the lowest roll resistance (example 5). Examples 3 and 4 were not calendered at the same temperature as the other samples. The melt viscosity of example 3 was too high to process at 170 ℃ and therefore a higher temperature of 175 ℃ was required. In contrast, example 4 had insufficient melt strength at 170 ℃ and required processing at a lower temperature of 160 ℃.
[0053] The data in table 5 below shows that the combination of lower i.v. and branched monomer, as shown in example 5, results in a reduction in bearing pressure between the calendering rolls at each roll speed.
TABLE 5
Influence of roll speed on bearing pressure at a roll gap of 0.2mm
Unplasticized composition
| Examples | 1 | 2 | 3 | 4 | 5 |
| Roll temperature, deg.C | 170 | 170 | 175 | 160 | 170 |
| Speed of the roller | Bearing pressure (kN) | ||||
| 5RPM | 32 | 31 | 41 | 27 | 24 |
| 10RPM | 38 | 37 | 34 | 34 | 28 |
| 15RPM | 41 | 44 | 36 | 35 | 32 |
| 20RPM | 44 | 47 | 38 | 39 | 33 |
[0054] The polymer processed on the calender will form a stock pile on top of the processing roll. The temperature of the pack is thus related to the shear heating and shear force thinning of the polyester. At such slower processing speeds of 5rpm, the normal heat conduction process from the hot metal rolls will heat the material. As the roll speed increases, the internal viscosity and shear thinning characteristics of the material strongly affect the windrow temperature. The data of table 6 were collected at a roll temperature of 170 c, but the data of example 4 were collected at 160 c. The lowest temperature rise was observed for example 5(IV 0.65 with 0.20% branching) as the roll speed increased, thereby indicating that the material was more sensitive to shear thinning. More sensitive shear thinning may allow the composition of example 5 to be processed at higher yields and at lower processing temperatures. Data at 5RPM for example 3 was not collected because the polyester composition did not form a viscous melt.
TABLE 6
Influence of roll speed on material temperature when roll gap is 0.2mm
Unplasticized composition
| Examples | 1 | 2 | 3 | 4 | 5 |
| Roll temperature, deg.C | 170 | 170 | 170 | 160 | 170 |
| Speed of the roller | Material temperature, DEG C | ||||
| 5RPM | 166 | 166 | Not testing | 159 | 168 |
| 10RPM | 174 | 175 | 169 | 165 | 170 |
| 15RPM | 176 | 183 | 174 | 168 | 175 |
| 20RPM | 181 | 186 | 178 | 170 | 175 |
[0055] Table 7 illustrates the occurrence of melt fracture in the calendered films as a function of roll speed. Melt fracture is determined by visual roughness, fogging or matting within the sheet. In table 7, "MF" indicates significant or severe melt fracture, while "slight" indicates that some fogging was observed. For the experiment labeled "transparent", no melt fracture was observed. As can be seen from the data in table 7, only the lower i.v. (example 4) or lower i.v. and branching combination polyesters had no melt fracture at the higher roll speeds.
TABLE 7
Influence of roll speed on melt fracture at a roll gap of 0.2mm
Unplasticized composition
| Examples | 1 | 2 | 3 | 4 | 5 |
| Roll temperature, deg.C | 170 | 170 | 175 | 160 | 170 |
| Speed of the roller | Occurrence of melt fracture | ||||
| 5RPM | Is transparent | Is transparent | Is transparent | Is transparent | Is transparent |
| 10RPM | Light and slight | Light and slight | Is transparent | Is transparent | Is transparent |
| 15RPM | MF | MF | MF | Is transparent | Is transparent |
| 20RPM | MF | MF | MF | Is transparent | Is transparent |
[0056]Examples 6 to 9. Calendering of the plasticized polyester. The polyesters of examples 1 and 3-5 were plasticized to form flexible polyester compositions. These PETG samples were premixed with a solution containing about 15 wt.% Tsunami®Mold release additive concentrate (Tsunami) of mixture of montan waxes from Copolyester GS-2®ADD2 available from Eastman Chemical Company). The final composition contained 0.9 wt% mold release additive and 15 wt% diethylene glycol dibenzoate (DEGDB) plasticizer from velsicol chemical corporation. The composition of each sample before calendering is shown in table 8. The i.v. data shown in table 8 were determined for PETG polyester prior to melt blending with additives and plasticizers. The polyester was not dried prior to melt blending and calendering. The polyester composition was applied to a Haake-Buchler Rheochard using a 375g loading drum®Prepared on System 40, drum temperature was 130 ℃ and blade speed was 100 rpm. LabView was used for each sample®Computer system recording moment and temperature at any timeTo change in time. After the torque of the mixing bowl reached its peak, mixing was allowed to continue until the melt temperature reached 150 ℃, and the batch was terminated and the material in the mixing bowl was removed.
TABLE 8
Plasticized polyester compositions for use in calendering experiments
| Examples | V. (dL/g) (PETG polymer) | DEGDB (% by weight) | Mold release additive (% by weight) | Branched monomer (% by weight) |
| 6 | 0.76 | 15 | 0.9 | 0 |
| 7 | 0.76 | 15 | 0.9 | 0.18 |
| 8 | 0.65 | 15 | 0.9 | 0 |
| 9 | 0.65 | 15 | 0.9 | 0.20 |
[0057] The rolling results are shown in tables 9 to 11. Many of the trends observed for the unplasticized samples are also present in the plasticized material. However, the difference in processing behavior is small due to the effect of the plasticizer on the processing. The plasticized composition is capable of being calendered at lower temperatures. Even with lower processing temperatures, the lower i.v. branched composition (example 9) still has lower bearing pressure and lower rotational force than the higher i.v. and unbranched materials. The charge temperature data for the plasticized compositions are shown in table 11; no significant difference in material temperature was observed. In tables 9 and 10, the data for example 9 is somewhat erroneous because low processing temperatures result in poor flow characteristics. The composition of example 7 did not flow well before the roller speed was increased to 20 rpm. The lower i.v. branched material (example 9) has lower rotational resistance and bearing pressure at the same processing temperature. It is expected that the lower rotational resistance and bearing pressure shown in example 9 may allow the composition to be calendered faster and/or at lower temperatures.
TABLE 9
Influence of roll speed on Total rotational resistance at a roll gap of 0.1mm
Plasticized composition
| Examples | 6 | 7 | 8 | 9 |
| Roll temperature, deg.C | 145 | 145 | 145 | 145 |
| Speed of the roller | Rotation resistance (Nm) | |||
| 5RPM | 239 | 284 | 168 | 146 |
| 10RPM | 258 | 339 | 203 | 185 |
| 20RPM | 290 | 262 | 219 | 194 |
Watch 10
Influence of roll speed on bearing pressure at a roll gap of 0.1mm
Plasticized composition
| Examples | 6 | 7 | 8 | 9 |
| Roll temperature, deg.C | 145 | 145 | 145 | 145 |
| Speed of the roller | Bearing pressure (kN) | |||
| 5RPM | 23 | 26 | 18 | 17 |
| 10RPM | 27 | 33 | 24 | 21 |
| 20RPM | 31 | 28 | 25 | 24 |
TABLE 11
Influence of roll speed on Material temperature at a roll gap of 0.2mm
Plasticized composition
| Examples | 6 | 7 | 8 | 9 |
| Roll temperature, deg.C | 145 | 145 | 145 | 145 |
| Speed of the roller | Material temperature, DEG C | |||
| 5RPM | 142 | 122 | 133 | 143 |
| 10RPM | 147 | 136 | 144 | 151 |
| 20RPM | 162 | 161 | 156 | 160 |
[0058] Examples 10 to 13. 4 samples of branched PETG containing 50 mole% 1, 4-cyclohexanedimethanol and 0.2 weight% 1, 2, 4-trimellitic anhydride with I.V. values ranging from 0.60 to 0.74dL/g and a crystallization half time from the molten state of > 1000 minutes were coated with 0.75 weight% montan wax release additive and calendered at a roll speed of 20RPM using the method of examples 1-5. The calendering results are shown in Table 12. The best process characteristics were obtained from the composition having an i.v. value of 0.65dL/g (example 12), as indicated by roll resistance, bearing pressure, and material temperature. But the composition of example 11 also gave satisfactory results under the experimental conditions. Example 13 could not be processed under the experimental calendering conditions.
TABLE 12
Effect of intrinsic viscosity on calendering (roll speed 20RPM)
| Examples | 10 | 11 | 12 | 13 |
| I.V.(dL/g) | 0.74 | 0.70 | 0.65 | 0.60 |
| Roll temperature, deg.C | 170 | 170 | 170 | 170 |
| Total resistance roll (Nm) | 490 | 422 | 381 | NA |
| Bearing pressure (kN) | 43 | 34 | 31 | NA |
| Material temperature, DEG C | 171 | 166 | 169 | NA |
Claims (33)
1. A polyester composition for calendering comprising
(a) A polyester comprising diacid residues, diol residues and branching monomer residues, wherein said polyester is a random copolymer having a crystallization half time from the molten state of at least 5 minutes and an intrinsic viscosity of from 0.55 to 0.75 dl/g; and
(b) an additive effective to prevent the polyester from sticking to the calender rolls.
2. The polyester composition of claim 1 wherein (i) the diacid residues comprise at least 80 mole percent, based on the total moles of diacid residues, of the residues of one or more of the following acids: terephthalic acid, naphthalenedicarboxylic acid and 1, 4-cyclohexanedicarboxylic acid or isophthalic acid; and (ii) the diol residues comprise 10 to 100 mole percent of residues of 1, 4-cyclohexanedimethanol, and 0 to 90 mole percent of residues of one or more of the following diols, based on the total moles of diol residues: ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, diethylene glycol, 1, 6-hexanediol, 1, 8-octanediol, 2, 4-trimethyl-1, 3-pentanediol, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, 1, 3-cyclohexanedimethanol, bisphenol a, or polyalkylene glycol.
3. The polyester composition of claim 2 wherein said diol residues comprise 10 to 100 mole% of residues of 1, 4-cyclohexanedimethanol and 0 to 90 mole% of residues of ethylene glycol.
4. The polyester composition of claim 3 wherein said diacid residues further comprise from 0 to 20 mole percent of the residues of one or more modifying diacids having from 4 to 40 carbon atoms.
5. The polyester composition of claim 4 wherein the modified diacid comprises one or more of the following acids: succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, azelaic acid, dimer acid, or sulfoisophthalic acid.
6. The polyester composition of claim 5 wherein said branching monomer residues comprise 0.05 to 1 weight percent, based on the total weight of said polyester, of the residues of one or more monomers comprising 3 or more carboxyl substituents, hydroxyl substituents, or combinations thereof.
7. The polyester composition of claim 6 wherein said branching monomer residues comprise 0.1 to 0.7 weight percent, based on the total weight of said polyester, of residues of one or more of the following compounds: 1, 2, 4-trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1, 2, 6-hexanetriol, pentaerythritol, trimethylolethane or 1, 3, 5-trimellitic acid.
8. The polyester composition of claim 7 wherein said additive comprises from 0.1 to 10 weight percent, based on the total weight of said polyester composition, of one or more of the following compounds: fatty acid amides, metal salts of organic acids, fatty acid salts, fatty acid esters, hydrocarbon waxes, ester waxes, phosphoric acid esters, chemically modified polyolefin waxes; glycerol esters, talc, or acrylic copolymers.
9. The polyester composition of claim 8, wherein the additive comprises one or more of the following compounds: erucamide, stearamide, calcium stearate, zinc stearate, stearic acid, montanic acid esters, montanic acid salts, oleic acid, palmitic acid, paraffin wax, polyethylene wax, polypropylene wax, carnauba wax, glyceryl monostearate or glyceryl distearate.
10. The polyester composition of claim 9 wherein said crystallization half time of said polyester is at least 12 minutes.
11. The polyester composition of claim 10, wherein the semicrystalline time is at least 30 minutes.
12. The polyester composition according to claim 1, wherein
The semi-crystallization time of the polyester from a molten state is at least 30 minutes and the intrinsic viscosity is 0.55-0.75 dL/g;
the diacid residues comprise at least 90 mole percent, based on the total moles of diacid residues, of residues of one or more of the following acids: terephthalic acid, naphthalenedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid or isophthalic acid;
the diol residues comprise 20 to 70 mole%, based on the total moles of diol residues, of residues of one or more of the following diols: 1, 4-cyclohexanedimethanol, neopentyl glycol or diethylene glycol, and 30 to 80 mole% of the residues of one or more diols selected from the group consisting of: ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 8-octanediol, 2, 4-trimethyl-1, 3-pentanediol, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, 1, 3-cyclohexanedimethanol, bisphenol a, and polyalkylene glycols.
The branched monomer residues comprise 0.05 to 0.7 weight percent, based on the total weight of the polyester, of residues of one or more of the following compounds: 1, 2, 4-trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1, 2, 6-hexanetriol, pentaerythritol, trimethylolethane or 1, 3, 5-trimellitic acid.
The polyester composition comprises 0.1 to 10 weight percent, based on the total weight of the polyester composition, of an additive effective to prevent the polyester from sticking to calendering rolls, wherein the additive comprises one or more of the following compounds: fatty acid amides, metal salts of organic acids, fatty acid salts, fatty acid esters, hydrocarbon waxes, ester waxes, phosphoric acid esters, chemically modified polyolefin waxes; glycerol esters, talc, or acrylic copolymers.
13. The polyester composition of claim 12, wherein the additive comprises (i) a fatty acid or salt of a fatty acid containing 18 or more carbon atoms and (ii) an ester wax comprising a fatty acid residue of 18 or more carbon atoms and an alcohol residue of 2 to 28 carbon atoms, wherein the ratio of the fatty acid or salt of a fatty acid to the ester wax is 1: 1 or greater.
14. The polyester composition of claim 13, wherein said fatty acid comprises montanic acid; the salts of the fatty acids comprise one or more of the following salts: sodium salt of montanic acid, calcium salt of montanic acid, or lithium salt of montanic acid; and the fatty acid residue of the ester wax comprises montanic acid.
15. The polyester composition of claim 12 further comprising a plasticizer comprising one or more aromatic rings, wherein said plasticizer dissolves a 5 mil (0.127mm) thick film of said polyester at 160 ℃ or less to form a clear solution.
16. The polyester composition of claim 15 wherein said plasticizer comprises diethylene glycol dibenzoate.
17. The polyester composition of claim 12, further comprising 5 to 40 wt% of a flame retardant comprising one or more mono-, di-, or tri-esters of phosphoric acid, based on the total weight of the polyester composition, wherein the flame retardant is miscible with the polyester.
18. The polyester composition of claim 17, wherein the flame retardant comprises resorcinol bis (diphenyl phosphate).
19. A process for the production of a film or sheet comprising calendering a polyester composition comprising:
(a) a polyester having a crystallization half time from the molten state of at least 30 minutes and an intrinsic viscosity of from 0.55 to 0.75dL/g, wherein the polyester is a random copolymer comprising:
(i) diacid residues comprising at least 80 mole percent, based on the total moles of diacid residues, of residues of one or more of the following acids: terephthalic acid, naphthalenedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid or isophthalic acid;
(ii) diol residues comprising 10 to 100 mole percent of residues of 1, 4-cyclohexanedimethanol, and 0 to 90 mole percent of residues of one or more diols selected from the group consisting of: ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, diethylene glycol, 1, 6-hexanediol, 1, 8-octanediol, 2, 4-trimethyl-1, 3-pentanediol, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, 1, 3-cyclohexanedimethanol, bisphenol a, and polyalkylene glycol; and
(iii) a branched monomer residue comprising from 0.05 to 1 weight percent, based on the total weight of the polyester, of the residue of one or more monomers comprising 3 or more carboxyl substituents, hydroxyl substituents, or a combination thereof; and
(b) an additive effective to prevent the polyester from sticking to the calender rolls.
20. The process of claim 19 wherein said branching monomer residues comprise from 0.1 to 0.7 weight percent, based on the total weight of said polyester, of residues of one or more of the following compounds: 1, 2, 4-trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1, 2, 6-hexanetriol, pentaerythritol, trimethylolethane or 1, 3, 5-trimellitic acid, and the intrinsic viscosity of the polyester composition is 0.55-0.7 dL/g.
21. The method of claim 20 wherein said diol residues comprise 10 to 100 mole percent of residues of 1, 4-cyclohexanedimethanol and 0 to 90 mole percent of residues of ethylene glycol.
22. The polyester composition of claim 21 wherein said diol residues comprise 20 to 80 mole percent of the residues of 1, 4-cyclohexanedimethanol and 20 to 80 mole percent of the residues of ethylene glycol.
23. The method of claim 22 wherein said diacid residues comprise residues of 95 to 100 mole percent terephthalic acid and said diol residues comprise residues of 20 to 65 mole percent 1, 4-cyclohexanedimethanol.
24. The process of claim 20 wherein said diacid residues further comprise from 0 to 20 mole percent of the residues of one or more modified diacids having from 4 to 40 carbon atoms.
25. The method of claim 24, wherein the modified diacid comprises one or more of the following diacids: succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, azelaic acid, dimer acid, or sulfoisophthalic acid.
26. The process of claim 20 wherein said additive comprises from 0.1 to 10 weight percent, based on the total weight of said polyester composition, of one or more of the following compounds: fatty acid amides, metal salts of organic acids, fatty acid salts, fatty acid esters, hydrocarbon waxes, ester waxes, phosphoric acid esters, chemically modified polyolefin waxes; glycerol esters, talc, or acrylic copolymers.
27. The method of claim 26, wherein the additive comprises one or more of the following compounds: erucamide, stearamide, calcium stearate, zinc stearate, stearic acid, montanic acid esters, montanic acid salts, oleic acid, palmitic acid, paraffin wax, polyethylene wax, polypropylene wax, carnauba wax, glyceryl monostearate or glyceryl distearate.
28. The process of claim 27 further comprising a plasticizer having one or more aromatic rings, wherein said plasticizer dissolves a 5 mil (0.127mm) thick film of said polyester at 160 ℃ or less to form a clear solution.
29. The method of claim 28, wherein the plasticizer comprises diethylene glycol dibenzoate.
30. The process of claim 20, further comprising 5 to 40 weight percent, based on the total weight of the polyester composition, of a flame retardant comprising one or more mono-, di-, or tri-esters of phosphoric acid.
31. The method of claim 30, wherein the flame retardant comprises resorcinol bis (diphenyl phosphate).
32. Film or sheet comprising
(a) A polyester having a crystallization half time from the molten state of at least 30 minutes and an intrinsic viscosity of from 0.55 to 0.70dL/g, wherein the polyester is a random copolymer comprising:
(i) diacid residues comprising at least 90 mole percent, based on the total moles of diacid residues, of residues of one or more of the following acids: terephthalic acid, naphthalenedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid or isophthalic acid;
(ii) diol residues comprising 10 to 100 mole%, based on the total moles of diol residues, of residues of one or more of the following diols: 1, 4-cyclohexanedimethanol, neopentyl glycol, or diethylene glycol, and 0 to 90 mole% of the residues of one or more diols selected from the group consisting of: ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 8-octanediol, 2, 4-trimethyl-1, 3-pentanediol, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, 1, 3-cyclohexanedimethanol, bisphenol a, and polyalkylene glycol; and
(iii) a branched monomer residue comprising from 0.05 to 0.7 weight percent, based on the total weight of the polyester, of the residue of one or more of the following compounds: 1, 2, 4-trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1, 2, 6-hexanetriol, pentaerythritol, trimethylolethane or 1, 3, 5-trimellitic acid; and
(b) 0.1 to 10 weight percent, based on the total weight of the polyester composition, of an additive effective to prevent sticking of said polyester to calendering rolls, wherein said additive comprises one or more of the following compounds: fatty acid amides, metal salts of organic acids, fatty acid salts, fatty acid esters, hydrocarbon waxes, ester waxes, phosphoric acid esters, chemically modified polyolefin waxes; glycerol ester, talc, or acrylic copolymers;
wherein the film or sheet is made by a calendering process.
33. A film or sheet made by the method of any one of claims 21, 22 or 25 to 31.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10/722,870 | 2003-11-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| HK1098167A true HK1098167A (en) | 2007-07-13 |
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