JPH0478652B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION The present invention relates to polyethylene terephthalate molding mixtures and more particularly to such mixtures which can be molded to obtain molded articles with improved flame retardancy. BACKGROUND OF THE INVENTION Polyethylene terephthalate is an inexpensive polymer, but until recently it has not been recognized as a good molding resin for a number of reasons. for example,
Alkali metal salts of certain organic carboxyl-containing compositions (alkali metal organic carboxylates)
is commonly added to promote crystallization by enhancing nucleation of polyethylene terephthalate. Furthermore, polyethylene terephthalate is generally made flame retardant by the addition of conventional flame retardants, such as halogenated organic compounds and antimony oxide synergists. However, when a flame retardant system containing an antimony oxide synergist is added to a mixture of polyethylene terephthalate and alkali metal organic carboxylate, polymer decomposition occurs resulting in decreased mechanical properties and decreased melt viscosity. This degradation in the presence of antimony oxide is particularly unfortunate since antimony oxide is a particularly good synergist for halogenated aromatic organic flame retardants. It is readily available, inexpensive and highly effective. In contrast, many other inorganic synergists are simply not effective in polyethylene terephthalate flame retardant systems or degrade the resin when used with polyethylene terephthalate, including zinc oxide, zinc sulfide, Zinc borate, stannous oxide, molybdenum oxide and molybdate. There is a need for a flame retardant system using antimony oxide that does not substantially affect the thermal stability of polyethylene terephthalate when added to a mixture of polyethylene terephthalate and an alkali metal carboxylate; This can be provided by the invention. SUMMARY OF THE INVENTION It has now been found that the destabilizing effect of antimony oxide on mixtures of alkali metal organic carboxylates is minimized when the antimony oxide is added in the form of a concentrate in the polyamide. This improves the stability of polyethylene terephthalate during compounding and subsequent melt processing operations, such as injection molding, when added in the form of concentrates in other heavy machinery polymers, such as polyethylene, or as is. Significant improvement compared to when adding In particular, the polyethylene terephthalate molding mixture of the present invention comprises: (a) from 20 to 90% by weight of the mixture, at least 0.4
polyethylene terephthalate having an inherent viscosity of (b) 0.1 to 20% by weight of the mixture of (a) and (b), from 7 to
Sodium and/or at least one carboxyl-containing organic compound selected from the class consisting of hydrocarbon monocarboxylic acids containing 25 carbon atoms, hydrocarbon di- or tricarboxylic acids containing 7 to 54 carbon atoms, and organic carboxyl-containing polymers. (c) a halogenated flame retardant consisting of an aromatic organic compound having at least one aromatic ring having sufficient halogen bonded directly to the aromatic ring carbon to provide flame retardancy; (d) the flame retardant is present in the mixture in an amount sufficient to provide the mixture with halogen in an amount of about 5 to 30% by weight based on the weight of the mixture of (a) and (c); 0.3 by weight based on the weight of the mixture of ) and (d)
~8% antimony oxide, the antimony oxide being added to the mixture in the form of a concentrate in the polyamide, the concentrate containing from 20 to 80% by weight of antimony oxide based on the combined weight of antimony oxide and polyamide , is defined as consisting of . Usually the mixture contains reinforcing agents or fillers ranging from 0 to 55% by weight. DESCRIPTION OF THE INVENTION Polyethylene Terephthalate The polyethylene terephthalate used in this invention has an inherent viscosity of at least 0.4 as measured by ASTM D-2857. Preferably, it has an upper limit on inherent viscosity of about 1.2. Inherent viscosity is 0.50 g per 100 ml of methylene chloride and trifluoroacetic acid mixture in a 3:1 ratio by volume.
Measured at 30°C at a concentration of Polyethylene terephthalate contains up to 50% by weight of e.g. diethylene glycol, glutaric acid, 1,4
- May contain other comonomers such as butanediol, polyalkylene oxide, cyclohexanedimethanol and other diols. Preferably, the polyethylene terephthalate is present in an amount of 35 to 70% by weight of the mixture. Reinforcement or Filler Materials Reinforcement or filler materials that can be used in the present invention include glass fibers, graphite fibers, aramid fibers, glass beads, aluminum silicate, asbestos, mica, etc., and combinations thereof. Preferably, this material is present in an amount of 15-55% by weight of the mixture. Alkali metal organic carboxylic acid salts Typical examples of salts of organic carboxylic acids include 2-5-
Ionic hydrocarbon copolymers of alpha-olefins of carbon atoms and alpha, beta ethylenically unsaturated carboxylic acids of 3 to 5 carbon atoms whose carboxyl groups are at least partially neutralized by sodium and/or potassium cations (hereinafter referred to as ionomer resin), for example, a copolymer of ethylene and acrylic or methacrylic acid. These copolymers are preferably sodium or potassium salts (preferably 30 to 95% neutralized) of ethylene/methacrylic acid copolymers. Styrene/maleic anhydride copolymers (including both fully or partially (eg, about 30%) neutralized salts) are also representative examples. The olefin moiety usually accounts for 50-98%, preferably 80-98% by weight of the copolymer. A particularly preferred material is the sodium salt of ethylene/methacrylic acid copolymer. The copolymer can be produced by a conventional high pressure polymerization method. contains at least 7, preferably at least 26, more preferably 30 to 54 carbon atoms, and about 1500
Salts of substantially aliphatic di- or tricarboxylic acids having a molecular weight below, preferably between 450 and 1000, are also another class of examples. These salts are based on polyethylene terephthalate and weigh approximately
It is present in the mixture in an amount of 0.1-5%, preferably 0.35-1.1%. Although both saturated and unsaturated polycarboxylic acids can be used for salt formation, saturated acids are preferred because of their lower tendency to discolor. Additionally, the acid may contain an aryl moiety, such as a phenylene, in the aliphatic chain. Representative substantially aliphatic polycarboxylic acids that can be used to form the salts useful in this invention include dimer acids and trimer acids. Dimer acid means C ₃₆ dicarboxylic acid obtained by dimerization of C ₁₈ fatty acids.
Trimer acid means C ₅₄ tricarboxylic acid obtained by trimerization of C ₁₈ fatty acids. Halogenated Flame Retardants Halogenated flame retardants consist of aromatic compounds containing a halogen, preferably a bromine or chlorine atom, bonded directly to an aromatic ring or rings. If bromine is present, it is at least 25% by weight of the compound, and if chlorine is present, chlorine is at least 40% by weight of the compound. In addition, the flame retardant compound must be substantially stable up to 300°C and must not cause degradation of the polyethylene terephthalate. If the compound contains bromine, the amount of bromine present in the mixture is preferably from 5 to 20% by weight of the mixture with component (a) alone. If the compound contains chlorine, the amount of chlorine present is preferably from 5 to 20% by weight of the mixture with compound (a) alone. Typical flame retardants include decabromodiphenyl ether, octabromodiphenyl ether, ethylene-bis-(tetrabromophthalimide), brominated polystyrene, poly(dibromophenylene oxide), decachlorodiphenyl ether, and octachlorodiphenyl ether. enyl ether, ethylene bis(tetrachlorophthalimide), chlorinated polystyrene,
Includes poly(dichlorophenylene oxide) and the like. Polymeric flame retardants can have molecular weights up to 200,000 or more. Antimony Oxide The antimony oxide (Sb ₂ O ₃ or Sb ₂ O ₅ ) used in the present invention is added as a concentrate in the polyamide. It is present in the polyethylene terephthalate mixture in an amount of 0.3 to 8%, preferably 0.3 to 5%, most preferably 0.3 to 1%, based on the weight of the mixture with component (a) alone. The concentration of antimony oxide in the concentrate (antimony oxide + polyamide) is 20-80% by weight. Polyamides useful as supports for antimony oxide are known in the art. They are of film-forming molecular weight. The polyamide resin can be produced by condensation of equimolar amounts of a saturated organic dicarboxylic acid containing from 4 to 12 carbon atoms and an organic diamine containing from 2 to 13 carbon atoms,
Therein, the diamines may be used, if necessary, in such a way that there is an excess of amine end groups over carboxyl end groups in the polyamide. Conversely, a diacid can also be used so that the acid end groups are in excess. Similarly, these polyamides can also be made from acidogenic and aminogenic derivatives of the amines and acids, such as esters, acid chlorides, amine salts, and the like. Representative dicarboxylic acids that can be used for the production of polyamides include adipic acid, pimelic acid, suberic acid, sebacic acid, and dodecanedioic acid, while representative diamines include hexamethylene diamine and octane diamine. Includes methylene diamine. In addition, polyamides can also be produced by self-condensation of ω-aminocarboxylic acids or lactams.
Examples of polyamides are poly(hexamethylene adipamide) (nylon 66), poly(hexamethylene azeramide) (nylon 69), poly(hexamethylene sebacamide) (nylon 610), and poly(hexamethylene dodecanoamide). ) (612 nylon), poly(4,
4′-methylenedicyclohexylendodecanoamide) or polyamides prepared by ring opening of lactams, i.e. polycaprolactam (nylon 6), polylauryllactam (nylon 12) or poly-11 prepared from ω-amino acids. -aminoundecanamide. For example, a copolymer of adipic acid, isophthalic acid and hexamethylene diamine; or hexamethylene diamine;
It is also possible to use polyamide copolymers produced by polymerization with at least two amines or acids for the production of the abovementioned polymers, such as copolymers of adipic acid and caprolactam. Also included are mixtures of polyamides such as nylon 66 and nylon 6. Other Additives In addition to the above-mentioned components, the mixture of the invention may contain, for example, colorants, mold release agents, antioxidants, toughening agents,
Additives commonly used with polyester resins can be included, such as nucleating agents, UV and heat stabilizers, and the like. Suitable additives are selected low molecular weight organic plasticizers which are esters, ketones, sulfones, sulfoxides, nitriles, amides or sulfonamides. Recently, good quality polyethylene terephthalate products have been developed by molding at relatively low temperatures, e.g. It has been found that it is possible to obtain When using these additive materials, the rate of crystallization is increased and molded products can be obtained with a smooth, shiny surface that allows easy demolding. When used, these additives are preferably present in an amount of 1 to 12% by weight of the mixture. In addition, the customary nucleating agents for polyethylene terephthalate, such as inorganic oxides or carbonates, carboxylic acids or other salts of sodium,
Polyethylene terephthalate oligomers can be used. Manufacture The mixtures of the invention are manufactured by melt mixing the components together by any convenient means to obtain an intimate mixture. Neither temperature nor pressure is limiting. For example, polyethylene terephthalate can be dry mixed or rolled with other ingredients in any suitable mixture and the mixture can be melt extruded. The extrudate may be shredded. If desired, the reinforcement or filler can be omitted initially and the resulting mixture then melt extruded. EXPERIMENTAL AND EXAMPLES In the following experiments and examples, percentages are based on the total mixture, unless stated otherwise. The properties of the molded bars were determined according to the following method: Tensile strength and elongation were determined by the method of ASTM D638 on injection molded bars at a pull rate of 0.2 inches per minute. Unnotched impact strength was measured according to ASTM D256 without notching the specimen. For this test and for tensile strength and elongation of Examples 1 and 2 for all samples, the specimens were heat treated in nitrogen at 150° C. for 16 hours. The melt viscosity of the extruded pellets was determined by a Monsanto Automatic capillary rheometer with a cylindrical orifice of 0.0305″ diameter and 0.62″ length.
Measurements were made at a constant shear stress of 125 kPa. In the experiments and examples, the manufacturing and testing method was as follows: Each component was dry mixed by hand, and the resulting mixture was then mixed in a two-stage 2-inch single-screw extruder.
It was extruded at a temperature of 300°C and a vacuum of 25-28 inches. After quenching the extruded strands in water, they were cut into pellets, which were then dried in a dehumidified air oven for 16 hours at about 95°C. The dried pellets were injection molded into bar specimens using a 6 oz. Vandoorne reciprocating injection molding machine at a rapid ram speed and a mold cavity temperature of about 105°C. The standard cycle has a melt temperature of approximately 307°C.
It was 33 seconds, corresponding to a residence time of 3 minutes. The severe cycle was 109 seconds, corresponding to a 10 minute residence time, at a melt temperature of about 312°C. Examples 1 and 2 without crystallization promoting additives were molded at a cavity temperature of about 50° C. and then tempered. Antimony oxide (70/30) in nylon 6 is M
&T Chemical Company. Other antimony oxide concentrates in nylon carriers were prepared by compounding the dry mixture in a 28 mm Werner and Freiderer twin screw extruder. The extruded strands are then quenched in water,
After cutting into pellets, they were dried in a dehumidified air oven at about 95° C. for 16 hours. The ingredients used in the experiments and examples are as follows: PET - polyethylene having an inherent viscosity of 0.6, measured at 30°C at a concentration of 0.50 g/100 ml in a mixture of 1 part trifluoroacetic acid and 3 parts dichloromethane. Terephthalate homopolymer resin "Surlyn" 8920 - about 60% by alkali metal organic carboxylate, i.e., ionic hydrocarbon copolymer, i.e., sodium
"Epon" copolymer of neutralized ethylene and 15% methacrylic acid by weight 1009 - condensation product of epichlorohydrin and bisphenol A with a molecular weight of 4000 to 8000 and approximately 0.53% oxirane oxygen . Obtained from Ciel Chemical Company. “Irganox” 1010 - Tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane brominated polystyrene from Ciba Geigy] - Brominated polystyrene (ferrochloride) with a bromine content of 68% Antimony Oxide - Sb ₂ O ₃ (“Thermogard” S from M&T Chemicals) 70% Sb ₂ O ₃ in Nylon 6 - “T/S” from M&T Chemicals "N-6 70/30 90% Sb ₂ O ₃ in polyethylene - M&T Chemical's "T/S" PE90/10 Glass fiber - PPG3540 1/8" Shredded glass fiber "Capron" 8200 - Allied Chemical Nylon 6 “Ultranox” 626 from BorgWarner Chemical - Bis(2,
4-di-t-butylphenyl)pentaerytol dimer acid sodium empol Obtained by neutralization of dimer acid with sodium hydroxide. Examples 1-3 and Comparative Examples A-D These experiments demonstrate that the difference in concentrate carrier (nylon and polyethylene) is important in compositions containing alkali metal carboxylates and PET. These experiments show that powdered antimony oxide alone (without carrier) causes more significant degradation than antimony oxide in a nylon carrier, similar to antimony oxide in polyethylene. All examples contain 1% antimony oxide, either neat (powder) or in a polymeric carrier. The composition is shown in Table 1, and the properties are shown in Table 2. A comparison of Example 1 and Comparative Example A shows that antimony oxide in polyethylene exhibits lower viscosity and somewhat poorer mechanical properties than antimony trioxide in nylon 6 for the alkali metal carboxylate/PET system. It shows giving. In a similar composition, the use of a nylon carrier (Example 2) provides a substantially higher melt viscosity and better mechanical properties than in powdered antimony trioxide (Comparative Example B), especially after harsh molding cycles. give. In the additional presence of a plasticizer (N-octadecyl p-toluenesulfonamide), antimony trioxide in nylon (Example 3) can be mixed with antimony trioxide in a polyethylene carrier (Comparative Example C) or pure powder (Comparative Example D) provides higher melt viscosity (and therefore less degradation) and superior properties than either of D). The effect is even more dramatic when the bar specimens are molded using a severe molding cycle.

【table】

【table】

[Table] Severe cycle;
Impact value without notch 〓〓 〓〓
14.8 9.9 11.0 6.8
8.9
Tensile strength, kpsi 〓〓 〓〓
23.0 19.4 21.0 14.8
17.8
Elongation, % 〓〓 〓〓
2.24 1.64 2.06 1.46
1.66
Examples 4-10 and Comparative Example E These experiments were carried out using 11.9% brominated polystyrene;
3.2% N-octadecyl p-toluenesulfonamide, 3.5% alkali metal carboxylate used in Examples 1-7 ("Surlyn" 8920),
Contains 0.65% pentaerythritol tetrastearate, 0.6% Epon 1009F, 0.2% Irganox 1010, and 1.0% antimony oxide added as a concentrate in the carrier. Examples 4 and 5 and Comparative Example E also contain 0.2% "Ultranox" 626. The remainder of the composition is PET
It is. Although the effectiveness of various nylon carriers varies, they generally provide compositions with higher melt viscosities and superior mechanical properties than are obtainable with inert polyethylene carriers.

【table】

【table】

TABLE Examples 11-14 and Comparative Examples F and G These experiments show that antimony oxide/polyamide concentrates are also effective when the alkali metal carboxylate is sodium dimerate. All experiments contained 1% antimony oxide.
The composition is shown in Table 4 along with the melt viscosity. Examples 11 and 12, along with Comparative Examples F and I,
Demonstrates the effectiveness of Sb ₂ O ₃ in nylon 6 when compared to Sb ₂ O ₃ . Comparative Examples G and H show that in the absence of an alkali metal carboxylate, there is no degradation due to antimony oxide.

【table】

Claims (1)

[Scope of Claims] 1 (a) 20 to 90% by weight of the mixture, at least
polyethylene terephthalate having an inherent viscosity of 0.4, (b) from 0.1 to 20% by weight of the mixture of (a) and (b), from 7 to
sodium and at least one carboxyl-containing organic compound selected from the class consisting of hydrocarbon monocarboxylic acids containing 25 carbon atoms, hydrocarbon di- or tricarboxylic acids containing 7 to 54 carbon atoms and organic carboxyl-containing polymers; (c) a halogenated flame retardant consisting of an aromatic organic compound having at least one aromatic ring containing sufficient halogen bonded directly to the aromatic ring carbon to provide flame retardancy; (d) the flame retardant is present in the mixture in an amount sufficient to provide the mixture with halogen in an amount of 5 to 30% by weight based on the weight of the mixture with (a); 0.3-8% antimony oxide by weight of the mixture, said antimony oxide being added to the mixture in the form of a concentrate in polyamide, said concentrate being 20-80% by weight based on the total weight of antimony oxide and polyamide. A polyethylene terephthalate molding mixture containing antimony oxide of . 2. Component (b) is a sodium or potassium salt of an ionic hydrocarbon copolymer present in an amount of 1 to 20% by weight of the mixture with (a).
Mixtures as described in Section. 3 Component (b) is 0.1 to 5% by weight of the mixture with (a)
A mixture according to claim 1, wherein the mixture is a sodium or potassium salt of a hydrocarbon di- or tricarboxylic acid of 7 to 54 carbon atoms present in an amount of . 4. A mixture according to claim 1, containing up to 55% by weight of the mixture of reinforcing or filler materials. 5 The ionic hydrocarbon copolymer of component (b) is 2-
3. A mixture according to claim 2, which is a sodium salt of a copolymer of an alpha-olefin of 5 carbon atoms and an alpha, beta-ethylenically unsaturated carboxylic acid of 3 to 5 carbon atoms. 6 Halogenated flame retardants include decabromodiphenyl ether, octabromodiphenyl ether, ethylene bis-(tetrabromophthalimide), brominated polystyrene, poly(dibromophenylene oxide), decachlorodiphenyl ether, octachlorodiphenyl ether , ethylene bis-(tetrachlorophthalimide), chlorinated polystyrene and poly(dichlorophenylene oxide). 7 Claim 1, which also contains a plasticizer,
The mixture according to item 2 or 3. 8. A mixture according to claim 1 in the form of pellets.