JPS6320267B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a flame-retardant polyethylene terephthalate composition with excellent mechanical properties and color tone. Polyethylene terephthalate (hereinafter referred to as PET) and polybutylene terephthalate (hereinafter referred to as PET)
Thermoplastic polyesters, typified by PBT (abbreviated as PBT), are finding use in a variety of industrial materials due to their excellent properties, but these industrial materials have common chemical and physical properties. In addition, flame retardancy is strongly required. Various compounds such as halogen-based, phosphorus-based, and nitrogen-based compounds are known as flame retardants for thermoplastic polyester, but although they all have the effect of imparting flame retardance, they are said to reduce the dynamics such as mechanical properties. There are advantages and disadvantages, and it is desired to realize a thermoplastic polyester composition that has a high degree of flame retardancy while retaining the properties of a polymer. In recent years, it has been known that certain polymeric flame retardants are effective as flame retardants for thermoplastic polyesters, and among them, halogenated polystyrene and halogenated poly-α-methylstyrene have a high degree of flame retardancy. However, although this flame retardant has somewhat good dispersibility in PBT, the dispersibility of the flame retardant is poor when applied to PET. Therefore, there is a problem that the mechanical properties are significantly deteriorated. Therefore, the present inventors conducted intensive studies to obtain an excellent PET composition with a balance between flame retardancy and mechanical properties. As a result, the present inventors decided to use halogenated polystyrene as a flame retardant and/or The present inventors have discovered that by blending halogenated poly-α-methylstyrene, the dispersibility of the flame retardant can be significantly improved and the above object can be effectively achieved, resulting in the present invention. That is, the present invention contains diethylene glycol units as a copolymerization component of 0.5 to 0.8% by weight.
Flame-retardant product made by blending 3 to 40 parts by weight of halogenated polystyrene and/or halogenated poly-α-methylstyrene represented by the following general formula () and 1 to 20 parts by weight of antimony trioxide to 100 parts by weight of PET. A PET composition is provided. (In the above formula (), R is a hydrogen atom or a methyl group, X is a bromine or chlorine atom, p is an integer of 1 to 5, and n is an integer of 2 or more) PET used in the present invention is terephthalic acid or its dialkyl It is obtained by polycondensation of ester and ethylene glycol, and is characterized by further containing diethylene glycol as a copolymerization component of 0.5 to 0.8% by weight.
If the coweight of diethylene glycol is less than 0.5% by weight, the dispersibility of the flame retardant will be poor, resulting in a significant decrease in mechanical properties, and if it exceeds 0.8% by weight, not only will the dispersibility of the flame retardant decrease, but also the heat resistance will deteriorate. This is not preferable because the properties of the composition decrease and the composition becomes noticeably colored. The PET of the present invention is obtained by polycondensation of terephthalic acid or its dialkyl ester, ethylene glycol, and a predetermined amount of diethylene glycol, but in some cases, esterification or transesterification of terephthalic acid or dialkyl ester with ethylene glycol may be performed. It can also be obtained by holding the product at a high temperature to produce diethylene glycol, which is then polycondensed. Note that the PET used in the present invention can be copolymerized with a small proportion of acid components other than terephthalic acid and diol components other than ethylene glycol and diethylene glycol, and furthermore, these PET can be used by blending a small proportion of other polymers. You can also do that. The halogenated polystyrene or halogenated polyα-methylstyrene of the above general formula () used as a flame retardant in the present invention can be obtained by polymerizing halogenated styrene or halogenated-α-methylstyrene, or by polymerizing polystyrene or polyα-methylstyrene.
-Produced by halogenating methylstyrene. Further, the flame retardant of the above general formula () can be used even if other vinyl compounds are copolymerized. In this case, the vinyl compounds include styrene, α-
Examples include methylstyrene, acrylonitrile, methyl acrylate, butyl acrylate, methyl methacrylate, butadiene, and vinyl acetate. The amount of halogenated polystyrene and/or halogenated poly-α-methylstyrene represented by the general formula () is 3 to 40 parts by weight, preferably 8 to 25 parts by weight, based on 100 parts by weight of the above PET. If it is less than 40 parts by weight, the flame retardance will not be sufficient, and if it is more than 40 parts by weight, the mechanical properties of the composition will be impaired, which is not preferable. The flame retardant effect of halogenated polystyrene and/or halogenated poly-α-methylstyrene can be significantly enhanced by adding antimony trioxide as a flame retardant aid. The amount added is 1 to 20 parts by weight, preferably 3 to 15 parts by weight, per 100 parts by weight of the thermoplastic polyester.If it is less than 1 part by weight, the flame retardance will not be sufficient, and if it is more than 20 parts by weight, the thermoplastic polyester will This is not preferred because mechanical properties are impaired. Furthermore, more preferably 2 to 5 halogens in the added halogenated polystyrene and/or halogenated poly-α-methylstyrene
It is preferable to add the antimony atom at a ratio of 1 atom to 1 atom of antimony in antimony trioxide. At the same time, flame retardant aids such as boron oxide, zirconium oxide, and iron oxide can also be used. There are no particular restrictions on the method of blending the composition of the present invention, such as melt-mixing the PET, flame retardant, and antimony trioxide in an extruder or kneader, or directly injection molding after homogeneously mechanically mixing the three components. Examples include a method in which PET is subjected to a machine and molded at the same time as mixing, and a method in which a flame retardant is directly added and mixed during the polymerization of PET. When compounding, general additives such as heat-resistant agents, stabilizers such as light-resistant agents, fibrous or powdered reinforcement/fillers, nucleating agents, lubricants, dyes, pigments, ultraviolet absorbers, foaming agents, plasticizers, and branching agents are used. Common PET modifiers such as agent thickeners and polyfunctional compounds can be added at the same time. The composition of the present invention is usually made into molded products by extrusion molding, injection molding, compression molding, etc., and these molded products not only have good flame retardancy, but also have good mechanical properties, melt flowability, and heat resistance inherent to PET. It maintains good electrical properties and electrical insulation properties, and has an excellent surface appearance, making it useful for applications such as mechanical parts, electrical parts, and automobile parts. The effects of the present invention will be explained below with reference to Examples. Note that all percentages and parts in the examples are based on weight. Moreover, relative viscosity is a value measured at 25° C. of a 0.5% polymer solution using 0-chlorophenol as a solvent. The diethylene glycol content in polyethylene terephthalate was determined by the method of Gaskill et al.
Chemistry Vol. 39, p. 106 (1967)) was used for quantitative determination using a gas chromatograph. Example 1, Comparative Example 1 100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, and 0.1 part of calcium acetate were gradually heated from 150°C to 240°C over 4 hours, transesterification was performed, and the methanol generated was continuously heated. Removed from the system. 0.03 parts of antimony trioxide and 0.03 parts of trimethyl phosphate were added to the obtained bisethylene glycol ester of terephthalic acid, and the pressure was gradually reduced at 290°C.
Polycondensation was carried out at 290℃ for 3 hours under reduced pressure of 0.3mmHg.
PET with a relative viscosity of 1.35 was obtained. As a result of measuring the diethylene glycol content in this PET, it was found to be 0.35%.
See Table 1 No. 4. On the other hand, 0.3 (No.
1), 0.5 (No. 2), 0.7 (No. 3), 2.0 (No. 5), 2.
5 (No.
6) Add each % and perform polycondensation in the same manner as above,
PETs having diethylene glycol contents shown in Table 1 were obtained. Next, for 100 parts of each of the above PET, add the following flame retardant (A),
Glass fibers (3 mm long chopped strands) and antimony trioxide (SBO) were mixed in a V-blender in the proportions shown in Table 1, and then melted and kneaded at 280°C using a 65 mmφ extruder to form pellets. Flame retardant (A) The pellets were vacuum dried at 130°C for 5 hours and then dried at 280°C.
The combustion specimens (1/8″×1/2″×5″ and 1/32″×1/2″×5″) and tensile dumbbell specimens were molded at a mold temperature of 130°C. . According to UL-94 standard using combustion test piece

[Table] A vertical combustion test and a tensile property test were conducted according to ASTM D-638. These results are shown in Table 1. From the results in Table 1, it is clear that the composition of the present invention has excellent flame retardancy and mechanical properties, and the color tone of the molded product is also excellent. Example 2, Comparative Example 2 Regarding No. 2 and No. 6 in Table 1 of Example 1, Example 2, Comparative Example 2, the following flame retardant (B) 12 was used instead of the flame retardant (A).
Table 2 shows the results of evaluating a test piece prepared in the same manner using 5 parts of antimony trioxide and 35 parts of glass fiber. Flame retardant (B)

[Table] It is clear from the results in Table 2 that the composition of the present invention has excellent mechanical properties. Example 3, Comparative Example 3 The diethylene glycol content shown in Table 3 obtained by the same method as Example 1 (diethylene glycol was 0 (No. 12, 15) with respect to the bisethylene glycol content of terephthalic acid during polycondensation), 0.3 (No.7), 0.5
(No. 8, 10), 0.7 (No. 9, 11), 2.0 (No. 13), 2.5
[No.
14) Added the following flame retardant to 100 parts by weight of PET
Evaluation was carried out in the same manner as flame retardant 1, except that (C) or (D), glass fiber (3 mm chopped strands) and antimony trioxide (SBO) were mixed in a V-blender in the proportions shown in Table 3. I did it. These results are shown in Table 3.

【table】

Claims (1)

[Scope of Claims] 1. Halogenated polystyrene and/or halogenated poly-α-methylstyrene represented by the following general formula () to 100 parts by weight of polyethylene terephthalate containing 0.5 to 0.8% by weight of diethylene glycol as a copolymerization component. A flame-retardant polyethylene terephthalate composition containing 3 to 40 parts by weight and 1 to 20 parts by weight of antimony trioxide. (In the above formula (1), R is a hydrogen atom or a methyl group, X is a bromine or chlorine atom, p is an integer of 1 to 5, and n is an integer of 2 or more)