JPH01256520A - Copolymerized polyester having excellent crystallinity at low temperature - Google Patents

Abstract

PURPOSE:To obtain a copolymerized polyester having improved moldability in injection molding at a low molding temp., by incorporating a specified polyfunctional component and a polyalkylene glycol component besides two constitutional components. CONSTITUTION:0.01-8mol% polyfunctional component (C) having at least two functional groups selected from among carboxylic acids and alcohols and also an alkali metal salt group of a carboxylic acid as a substituent (e.g., an alkali metal salt of dimethylolpropionic acid) based on the component A and furthermore 1-50wt.% polyalkylene glycol component (D) having a number-average MW of 400-4,000 (e.g., polyethylene glycol) based on a polyester consisting of both components A and B are incorporated in a polyester consisting of a dicarboxylic acid component (A) wherein the main component is terephthalic acid and a glycol component (B) wherein the main component is ethylene glycol. A copolymerized polyester having improved moldability in injection molding at a low mold temp. which is 100 deg.C or lower can be obtd. without detriment to excellent properties such as high m.p. and high rigidity which polyethylene terephthalate has.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial use amount: 1 ton] The present invention relates to a copolyester having extremely excellent crystallization properties and improved moldability.

[Conventional technology]

Polyalkylene terephthalates are of great importance as raw materials for the production of fibers, films or moldings. Among them, polyethylene terephthalate (hereinafter abbreviated as PgT) is particularly suitable for manufacturing various industrial products because of its many excellent physical properties such as heat resistance, chemical resistance, mechanical properties, and electrical properties. However, when this polyethylene terephthalate is used as an injection molded product for plastic applications, it is known that there are major drawbacks in terms of molding and physical properties due to the crystallization behavior of PET. That is, since PET has a low crystallization rate at low temperatures, it is difficult to obtain a molded product with good crystallization when injection molding is performed at a mold temperature of, for example, 130° C. or less, and only a molded product with poor surface hardness is obtained. Moreover, if the obtained molded product is used at a temperature higher than the glass transition point, crystallization progresses, resulting in poor shape stability.゛Again. Surface roughness also occurs due to non-uniform crystallization within the mold, and this poses many problems as a resin for injection molding.

Furthermore, molding is carried out at a mold temperature of around 50°C, and PE
In some cases, a method is used in which a molded product with almost no crystallized T is heat-treated, but this method is not only inefficient, but also causes the crystallized molded product to shrink in volume due to heat treatment. It has drawbacks such as bending and deformation.

Therefore, PET molding is usually carried out using a special molding machine that can achieve a mold temperature of 130°C or higher.
Since molding machines such as No. 7 are not common, a PET resin that can be molded well using a commonly used molding machine with a mold temperature of 80 to 100° C. or lower has been desired.

In order to solve the above problems, various methods have been proposed to improve the moldability of PET.

Addition of metal salt compounds of organic carboxylic acids as crystal nucleating agents (nucleating agents) is particularly effective, and has been proposed for aromatic acids such as sodium benzoate and sodium stearate. Further, Japanese Patent Publication No. 45-26225 proposes the addition of a metal salt of a copolymer of an α-olefin and an α,β-unsaturated carboxylic acid. JP-A-56-92918 proposes a method in which the terminal groups of polyester are converted into metal salts such as carboxylic acids. Furthermore, USP 4,548,9
No. 78 discloses a method in which a polyalkylene glycol component is contained as a crystallization aid in PET, and a known nucleating agent is further added thereto.

[Problem to be solved by the invention]

Special Publication No. 46-29977 and Special Publication No. 1450 of 1977
The method disclosed in Publication No. 2 has a problem in that when the metal salt compound is added, the molecular weight of PET is drastically reduced during molding. In the method according to Japanese Patent Publication No. 45-26225,
Problems arise such as a decrease in the mechanical strength of the molded product and visual deterioration during heating. Furthermore, since the metal salt has poor uniform dispersibility in the polymer, the obtained molded product is non-uniform in terms of crystallinity9 and is inferior in terms of dimensional stability and shape stability. Become. Furthermore, Japanese Patent Application Laid-Open No. 56-92918
In the method disclosed in the publication, a metal base such as a carboxylic acid is introduced only at the end of the molecule. Therefore, in the case of ordinary polyester, only two bases are introduced per molecule at most, and it has a remarkable effect of promoting crystallization. It is difficult to obtain. In addition, in order to obtain the polyester having a sufficiently high molecular weight, it is necessary to carry out the polycondensation reaction for a longer time than usual, which causes the problem that the color of the polymer increases, making it difficult to obtain the desired high molecular weight polyester. There is. u8p4,
The method according to No. 548,978 also has a mold temperature of 10
If the temperature is below 0°C, it is not possible to obtain a good molded product.

Therefore, the object of the present invention is to develop a new PET that has improved moldability in injection molding at a low mold temperature of 100°C or less without impairing the excellent properties of PET such as high melting point and high rigidity.
An object of the present invention is to provide an ET-based copolyester.

[Means to solve the problem]

The present inventors have discovered that, in addition to the main components terephthalic acid and ethylene glycol, as constituent components of the polymer,
The present inventors have discovered that the above object can be achieved by copolymerizing a polyester with a polyfunctional component having an alkali metal base of carboxylic acid and a polyalkylene glycol component, and have completed the present invention.

That is, the present invention provides a polyester comprising a dicarboxylic acid component a mainly composed of terephthalic acid and a glycol component mainly composed of ethylene glycol, which has at least two functional groups selected from carboxylic acids or alcohols.

and polyfunctional component C having an alkali metal base of carboxylic acid is added to component a in an amount of 0. A copolymerized polyester with excellent crystallinity containing 1 to 8 O and 1 to 50% by weight of a polyalkylene glycol component d having a number average molecular weight of 400 to 4,000 based on the polyester consisting of both components a and b. This is what we provide.

The dicarboxylic acid component a in the present invention is primarily a terephthalic acid component, but a part of it, i.e. 1
Less than 0 mol of the dicarboxylic acid component other than the terephthalic acid component may be substituted.

Examples of dicarboxylic acid components other than the terephthalic acid component include aromatic dicarboxylic acids such as inphthalic acid, phthalic acid, naphthalene dicarboxylic acid, diphenoquinethanedicarboxylic acid, and diphenyldicarboxylic acid, and adipic acid,... ...Also include aliphatic or alicyclic dicarboxylic acids such as fuclohexane-1,4-dicarboxylic acid.

The glycol component in the present invention mainly refers to ethylene glycol, but a portion thereof, ie, less than 10 moles, may be replaced with other glycol components other than the ethylene glycol component. Examples of such glycol components include aliphatic or alicyclic glycols such as trimethylene glycol, tetramethylene glycol, hexyl meflene glycol, neopentyl glycol, and cyclohexane-1,4-dimetatool; Aromatic glycols such as hydroquinone, resorcinol, and bisphenols can also be exemplified. Furthermore, oxycarboxylic acids such as oxybenzoic acid, oxycarboxylic acid, and hydroxyethoxybenzoic acid may be copolymerized.

Examples of the polyfunctional component C in the present invention include aliphatic, alicyclic, or aromatic polyoxycarboxylic acids having 3 or more carbon atoms, preferably 3 to 22 carbon atoms, and mono- or dialkali metal salts of polycarboxylic acids. Among these, dioxydicarboxylic acids and dioxymonocarboxylic acids are preferred, and the most preferred are dioxymonocarboxylic acids, such as alkali metal salts of dimethylolpropionic acid. Specific examples of the polyfunctional component C other than those mentioned above include monooxypolycarboxylic acids such as tartronic acid, malic acid and other alkali metal salts, monooxypolycarboxylic acids such as alkali metal salts such as citric acid, diotucine monocarboxylic acid, etc. , e.g. ≠ lyceric acid, 4,4-bis(4-hydroxychlorohexyl) acid.

9. Alkali metal salts such as lO-dioxyoctadecanoic acid can be added to dioxydicarboxylic acids such as tartaric acid, α,β-dioxyglutaric acid, α,δ-dioquine adipic acid, 6.
Alkali metal salts such as 7-cyoxydodecanedioic acid, 7.8-dioquinhexadecanedioic acid, furionic acid, and dioquine fumaric acid can be used to prepare polyquine polycarboxylic acids, such as desoxalic acid and oxycitric acid. Examples include alkali metal salts of carboxylic acids such as benzenetricarboxylic acid and benzenetetracarboxylic acid.

These oxycarboxylic acids may be substituted with a non-functional substituent such as an alkyl group.

The present invention is not limited to these exemplary components.

Examples of alkali metal salts include lithium salts, sodium salts, potassium salts, cesium salts, etc., and sodium salts or potassium salts are particularly preferably used.

The content of the polyfunctional component C in the polyester to achieve the object of the present invention is 0.01 to 8 mol%, more preferably 0.1% by mole based on the dicarboxylic acid component a.
~5 molti. If it is less than 0.01 mole, it has no practical effect on promoting crystallization, which is the objective of the present invention, while if it is added in excess of 8 mole, mechanical properties will deteriorate, which is not preferable.

The polyalkylene glycol component d in the present invention is polyethylene glycol, polypropylene glycol, polytetramethylene glycol, glycol of a copolymer of ethylene oxide and globylene oxide, or one end thereof is an alkyl group, aryl group, or aryl group. One or more derivatives bonded to each other by an ester bond, an ether bond, etc. are used. Particular preference is given to using polyethylene glycol and/or polytetramethylene glycol.

It is important that the number average molecular weight of the polyalkylene glycol component d is in the range of 400 to 4,000. If the number average molecular weight of the polyalkylene glycol component d is less than 400, the heat distortion temperature will be low and the heat resistance will be poor. On the other hand, if it is larger than 4,000, the surface gloss of the molded product will be poor, which is not preferable.

The proportion of the polyalkylene glycol component (d) in the present invention is 1 to 50 parts by weight, preferably 3 to 30 parts by weight, based on the polyester consisting of the dicarboxylic acid component a and the glycol component.

If the amount is less than 1 Jt%, the crystallinity improvement effect of the present invention will be small, which is not preferable. On the other hand, if it exceeds 50% by weight, the heat deformation temperature will be low and the heat resistance will be poor, and the rigidity of the molded product will decrease, which is not preferable.

The greatest feature of the present invention is that, in addition to the above two components a and b, the polyester component C has an alkali metal salt of a carboxylic acid that can act as a crystallization nucleating agent, and a polyfunctional component C as a crystallization aid. The polyalkylene glycol component d which can act is copolymerized into the polyester. The polyfunctional component and the polyalkylene glycol component can be introduced into the polyester by reacting these components with the dicarboxylic acid component a or the glycol component, or a reaction product thereof, to avoid polycondensation. It is possible. Alternatively, this can also be achieved by a method in which the polyfunctional component C and the polyalkylene glycol component d are separately reacted with the dicarboxylic acid component a and the glycol component or a reactant thereof to cause polycondensation, and then the two are mixed. obtain.

In the present invention, the polyfunctional component C and the polyalkylene glycol component d may be introduced into the copolymerized polyester in any bonding manner. That is, of course, when the polyfunctional component C is introduced by an esterification reaction using its ester-forming functional group and a reaction with other components constituting the copolyester, the polyfunctional component C is a polyalkylene glycol. This includes the case where it is directly bonded to component d via an ether group. For example, polyalkylene glycols having a carboxylic acid metal salt in the molecule obtained by subjecting one or both of the hydroxyl groups of a dimethylolpropionate metal salt to an addition reaction with ethylene oxide or the like are also included in the present invention.

The copolymerized polyester of the present invention is produced by a known method normally used for producing polyester. Polyesters are generally prepared by heating a mixture of reactants in the presence or absence of a catalyst at atmospheric or elevated pressure under an inert gas atmosphere. In that case, each raw material component is used in the form of an acid or alcohol or an ester-forming derivative thereof. The temperature adopted to carry out those reactions is 180"0 to 270℃
The temperature is preferably in the range of 210 to 260°C. After completion of this reaction, the resulting oligomer product is subjected to polycondensation.

The polycondensation reaction is carried out using known polycondensation catalysts such as antimony,
In the presence of compounds such as kermaniwam, titanium, zinc, cobalt, manganese, etc., 10■H2 or less, preferably 1 mHf
The following pressures and temperatures range from 260 to 295°C.

In the case of the copolymerized polyester of the present invention, the polyfunctional component C and the polyalkylene glycol component d can be added at any stage during the production of the polyester, for example, at the stage of esterification or transesterification, or at the stage of polycondensation. It may be added stepwise, or it may be added after polycondensation and the polycondensation may be continued to complete the reaction.

The intrinsic viscosity of the copolymerized polyester of the present invention is 0.35 to 1.5, preferably 0.0 when measured in a mixed solvent system of equal weights of phenol and tetrachloroethane at 30°C.
．． It is in the range of 45 to 1.3. If the intrinsic viscosity is less than 0.35, the strength and physical properties of the polyester will deteriorate, which is undesirable, and if it exceeds 1.5, the melt viscosity will increase significantly, causing problems particularly in injection molding.

In the copolymerized polyester obtained according to the present invention, the polyfunctional component C is introduced into the polymer molecule by copolymerization.

For example, in the copolymerized polyester of the present invention obtained from terephthalic acid, ethylene glycol, sodium dimethylolpropionate, and polyethylene glycol,
5 Q Q of the polyester (solvent ditrifluoroacetic acid)
In the MHz 'H-NMR spectrum, the absorption of the proton of the methyl group was observed as a singlet at the position of 1.3 ppm, and the copolyester was used as a solvent (a mixed solvent of equal weights of phenol and tetrachloroethane). The absorption of protons of methyl groups is observed in the same way (position and intensity) in the sample dissolved in water and reprecipitated with methanol. In the same spectrum, the absorption of the proton of the methyl group is 1
．． l PPm & 1.21) Pm and 1.3ppm
Each peak appears at the position of Hs HO-CH2-C-CH2-OH (-0f (s proto>: 1.1 ppm)0ONa (i'Ha).

Considering that it can be assigned to the structure of .

However, this does not exclude the case where the polyfunctional component C is bonded to the terminal in the copolymerized polyester of the present invention.

In the copolymerized polyester of the present invention, as mentioned above, the alkali metal base-containing component C of the carboxylic acid that can act as a crystal nucleating agent and the polyalkylene glycol component d that can act as a crystallization aid are both already polymerized as constituent components of the polyester. Since it is incorporated into the combined molecule, it is characterized by a sufficiently high crystallization rate even when used alone, and a low glass transition temperature. Therefore, when used as a molding material, it is virtually unnecessary to separately incorporate a crystal nucleating agent, which is required with conventional PET, and the problems associated with the addition of such a nucleating agent are naturally eliminated. Moreover, excellent moldability can now be obtained even at low molding temperatures of 100°C or less, which was difficult with conventional PET. Furthermore, the copolyester of the present invention having such excellent crystallization properties has sufficiently good thermal properties and mechanical properties, making it preferable as a molding material.

In the copolymerized polyester obtained according to the present invention, a plasticizer may be added, if necessary, in order to improve the crystallinity of the polyester at low temperatures. As such a substance, any known substance can be used as long as it functions as described above.

Examples of such include, for example, aliphatic esters of polyhydric alcohols, aromatic esters of polyhydric alcohols, esters of polyhydric carboxylic acids, polyalkylene glycols, polyalkylene glyco-mono- or dialkyl ethers. polyester diols consisting of aliphatic glycol and aliphatic dicarboxylic acid, polyester diols obtained by ring-opening polymerization of cyclic polyesters (lactones), mono- or dialiphatic and/or aromatic carboxylic acids of various polyester diols Examples include esters, aromatic sulfonic acid amides, aromatic sodium sulfonate, and fluorinated polyolefins.

Among these substances, polyalkylene glycols and mono- or dialkyl ethers of polyalkylene glycols are preferably used.

Among them, the general formula (R1, R't is Hl or alkyl having 1 to 10 carbon atoms,
It represents acyl and aroyl, and %R2 represents an alkylene group having 2 to 4 carbon atoms. Further, n is a number of 5 or more. ) Polyalkylene glycols represented by these are preferred. Particularly preferred are substances in which R1 and i<t are lower alkyl groups. For example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and their mono- or dialkyl ethers (e.g. monomethyl or dimethyl ether, monoethyl or diethyl ether, monopropyl or dipropyl ether,
mono- or sialylates (such as mono- or dibutyl ether), mono- or sialylates (such as mono-acetylate, diacetate, mono-2-ethyl
dibenzoate, di-2-ethylhexanoate, monobenzoate, dibenzoate, etc.). In the present invention, it is preferable that the polyalkylene glycol has alkyl ether at both ends, since the inherent viscosity of the polyester resin during molding is less likely to decrease. If a monoalkyl ether in which only one end is etherified or a polyalkylene glycol in which both ends are hydroxyl groups are used, the intrinsic viscosity of the polyester resin during molding will decrease significantly, so when using these, it is necessary to use a high degree of polymerization. It is necessary to use a polyester resin of The degree of polymerization n of the polyalkylene glycol (1) needs to be 5 or more; if it is less than 5, the polyalkylene glycol (1) tends to stand out on the surface of the molded product, which is not preferable. The appropriate amount of polyalkylene glycol (1) to be used is 10 parts by weight or less, preferably 5 parts by weight or less, per 100 parts by weight of the copolymerized polyester. If the amount exceeds 10 parts by weight, the rigidity of the molded product will decrease, which is inappropriate.

It is also possible to add a crystal nucleating agent to the copolymerized polyester of the present invention in the hope of further improving the amorphous rate.

Furthermore, if necessary, organic halogen-based and phosphorus-based flame retardants known in the art may be used. Particularly preferred flame retardants include poly(halogenated styrene)-1 halogenated poxy compounds.

Further, various flame retardant aids can be used in combination with flame retardants. Specific examples of flame retardant aids used include antimony compounds such as antimony trioxide and sodium antimonate, salts of balates, aluminum hydroxide, zirconium oxide, and molybdenum oxide.

In the copolymerized polyester of the present invention, various additives other than the above-mentioned components for the purpose of improving properties within a range that does not impair the effects of the present invention 1 For example, colorants, mold release agents, antioxidants, ultraviolet rays, etc. Stabilizers and fillers other than glass fiber can be added.

It is also possible to blend other polymers such as polyester resins, polyolefin resins, acrylic resins, polycarbonate resins, polyamide resins, rubber-like elastic bodies, and the like.

The copolyester of the present invention is molded into a desired shape such as a fiber, film, sheet, bottle, container, laminate, etc. using a molding machine such as an injection molding machine, an extrusion molding machine, a blow molding machine, or a compression molding machine. be able to.

The present invention will be explained in further detail by giving examples below.

In the present invention, all parts in the examples are based on weight.

Examples 1 to 9, Comparative Example 1 - 97 parts of dimethyl terephthalate (DMT), 6811 tlS of ethylene glycol, 0.024 s% of manganese acetate
0.1 part of Irganox 1010 (sterically hindered phenol manufactured by Ciba Geigy) as an antioxidant and sodium dimethylolpropionate and polyalkylene glycol component d as the polyfunctional component C in the types and proportions shown in Table 1, and a stirrer. , and charged into a reactor equipped with a rectification column and a methanol distillation condenser. Then from 150℃ to 235℃
The methanol produced by the reaction is distilled out of the system, and a twin-ester exchange reaction is carried out. About 3 hours after the start of the reaction, when the distillation of methanol is completed, 0.097 parts of phosphorous acid is added as a stabilizer. And 0.034 part of antimony trioxide was added as a polycondensation catalyst. The obtained reaction mixture was transferred to a reactor equipped with a stirrer and an ethylene glycol distillation condenser, and while the temperature was gradually raised from 235°C to 275°C, the pressure of the system was gradually reduced from normal pressure to a high vacuum of 1 ■Hy or less. The condensation reaction proceeded without lowering the temperature. The polycondensation reaction was terminated when a predetermined melt viscosity was reached. The obtained polymer was evaluated as follows, and the results are shown in Table 1.

The limiting viscosity [η] of the polymer was measured at 30° C. using a mixed solvent system of equal amounts of phenol and tetrachloroethane.

Crystallinity was evaluated from ΔT and Tch, which were determined by the following method; Δ'r = Tcc - Tch T... is the result of placing the sample in a calorimeter and placing it in a nitrogen stream at 1i°C for 5 minutes. After melting, it indicates the exothermic peak temperature when cooled at a cooling rate of 10°C/min, while Tch indicates the temperature at which the dried sample was cooled at 2°C/min.
Shows the crystallization exothermic peak temperature when the temperature is raised at a temperature increase rate of 10°C/min for a nearly amorphous film sample formed into a film of about 50μ by a heat press heated to 85°C and quenched with liquid nitrogen. . Regarding the relationship between crystallinity and these peak temperatures determined by DSC, the larger ΔT (i.e.,
The higher the Tea and the lower the Tch), the faster the crystallization rate is, and the larger the ΔT and the lower the Tch, the better the injection moldability can be achieved with a lower temperature mold.

The melting point (Tm), which is inferior to an index of heat resistance, was expressed by the crystalline melting peak obtained when the amorphous film was subjected to DSC measurement at a heating rate of 10° C./min.

In Table 1, the molecular weight of polyalkylene glycol is JIS
It is calculated from the terminal hydroxyl value determined based on K1557.

Below is a blank space.The polymer obtained in Example 3 was dissolved in trifluoroacetic acid and analyzed by 500MHz'H-NMR. As a result, absorption of protons of methyl group was observed as an nglet at the position of %1.3PPm. . In addition, the polymer
Similar NM for the sample dissolved in an isobaric tht mixed solvent of enol and tetrachloroethane and reprecipitated with methanol.
When R analysis was performed, the absorption of the proton of the methyl group was 1. The same intensity was observed at the a ppm position.

Example 10 100 parts by weight of the copolymerized polyester obtained in Example 3 and 3 parts by weight of polyethylene glycol dimethyl ether (average molecular weight of the polyethylene glycol portion: 1000) were dried in advance and mixed, and then mixed with Plastograph (manufactured by Brapender, PL). -3000 model) (conditions: 275°C, rotor speed 30 rpm). The obtained composition was evaluated in the same manner as in Example 3, and the results are shown in Table 1.

As is clear from Table 1, the copolyesters according to the present invention (Examples 1 to 9) have lower Tch and lower Tch than PET (Comparative Example 1) or copolyesters not containing component C (Comparative Example 2). It has excellent crystallinity due to its large ΔT, and has good heat resistance with no significant decrease in Tm due to modification. If the amount of component CO is too small (
In Comparative Example 3), ΔT was small and the effect of improving crystallinity was poor. When the amount of component d added is too small (Comparative Example 4), Tc
The decrease in h was insufficient and ΔT was small.

Example 11.12 A slurry consisting of 83 m of terephthalic acid (TA), 36.5 parts of ethylene glycol, 0.03 g of phosphorous acid, and 0.0348 g of antimony trioxide was prepared with a stirrer, a rectification column, and a cooling tube for water distillation. Esterification reaction was carried out at a temperature of 250 to 255° C. under a pressure of 2.6 kf/dG while gradually and continuously charging the reactor.

Next, after the reaction system was brought to normal pressure, 0.1tt151 of Irganox 1010 (manufactured by Ciba Geigy) as an antioxidant, 20 parts of polyethylene glycol having a molecular weight of 1,000, and Table 2. Ingredient C was added in various proportions and then stirred for an additional 10 minutes. The resulting reaction mixture was transferred to a polycondensation reactor, and while the temperature was gradually raised from 250°C to 275°C, the pressure of the system was lowered from normal pressure to a high vacuum of 1 ml-1p or less to proceed with the condensation reaction. The polycondensation reaction was terminated when a predetermined melt viscosity was reached, and the obtained polymer was evaluated in the same manner as described above. The results are shown in Table 2.

It is clear that all the copolyesters of the present invention have excellent crystallinity.

Example 13 683 parts by weight of the copolymerized polyester obtained in Example 3, 2 parts by weight of polyethylene glycol dimethyl ether (average molecular weight of the polyethylene glycol portion: 1.000), and 3 parts by weight of phlogopite (Cran, Sugilite Mica 200HK)
0 parts by weight was dried in advance and the cylinder temperature was 250-2.
The mixture was melt-kneaded at 75-275-275°C (with a hopper) and a die temperature of 265°C, and then extruded to obtain strand pellets.

After drying this pellet at 120°C for 15 hours, injection molding + 1k (FS80S12A manufactured by Nissei Jushi Kogyo ■) with the cylinder temperature kept at 250-275-275-275"C
Sh: ), by changing the mold temperature variously,
A flat test piece with 80 squares in width and 3 mm in thickness was molded.

The surface gloss of the obtained test piece was measured using a gloss needle (manufactured by Suga Test Instruments,
Measured using a digital variable angle glossy needle (UGV-50fi).

The results are shown in Table 3.

Example 14 Example 1 except that Merck (manufactured by Hayashi Kasei ■, Micron White 5008) was used as a substitute for phlogopite in Example 13.
Evaluation was made in the same manner as in 3. The results are shown in Table 3.

Comparative Example 5 Evaluation was carried out in the same manner as in Example 13, except that the PET obtained in Comparative Example 1 was used in place of the copolymerized polyester. The results are shown in Table 3.

Comparative Example 6 Evaluation was carried out in the same manner as in Example 14, except that the PET obtained in Comparative Example 1 was used in place of the copolymerized polyester 9. The results are shown in Table 3.

Table 3 As is clear from Table 3, when the copolymerized polyester of the present invention was used, crystallization proceeded sufficiently even at low mold temperatures, and a molded product with extremely high gloss was obtained.◎ On the other hand, PET In the case where the molding temperature was 120° C. or lower, no glossy molded product could be obtained, and the glossiness only showed a low value.

〔Effect of the invention〕

According to the present invention, a copolymer polyester having excellent crystallization properties and suitable for injection molding using a mold at a low temperature of 100° C. or less can be obtained.

Patent applicant RiRashi Co., Ltd.

Claims (1)

[Claims] 1. A polyester consisting of a dicarboxylic acid component (a) mainly consisting of terephthalic acid and a glycol component (b) mainly consisting of ethylene glycol, containing at least two functional groups selected from carboxylic acids or alcohols. and contains 0.01 to 8 mol% of a polyfunctional component c having an alkali metal base of a carboxylic acid based on component a, and further contains a polyalkylene glycol component d having a number average molecular weight of 400 to 4,000. A copolymerized polyester with excellent crystallinity, containing 1 to 50% by weight of the polyester consisting of both components a and b. 2. The copolymerized polyester according to claim 1, wherein at least 90 mol% of the dicarboxylic acid component a is a terephthalic acid component, and at least 90 mol% of the glycol component b is an ethylene glycol component. 3. The copolymerized polyester according to claim 1 or 2, wherein the polyfunctional component c having an alkali metal base of a carboxylic acid is an alkali metal salt of a dioxymonocarboxylic acid. 4. The copolymerized polyester according to claim 1 or 2, wherein the polyfunctional component c having an alkali metal base of carboxylic acid is an alkali metal salt of dimethylolpropionic acid. 5. The copolymerized polyester according to any one of claims 1 to 4, wherein the proportion of the polyfunctional component c having an alkali metal base of carboxylic acid to the component a is 0.1 to 5 mol%. 6. The copolymerized polyester according to any one of claims 1 to 5, wherein the proportion of the polyalkylene glycol component d to the polyester consisting of both components a and b is 3 to 30% by weight. 7. The copolymerized polyester according to any one of claims 1 to 6, wherein the polyalkylene glycol component d is polyethylene glycol and/or polytetramethylene glycol. 8. The copolymerized polyester according to any one of claims 1 to 7, which has an intrinsic viscosity of 0.35 to 1.5.