JPH06329887A - Polyester resin composition and its molding - Google Patents

Abstract

PURPOSE:To obtain the subject composition excellent in heat stability, melt stability and long-term durablity, excellent in adhesion and airtightness and suitable for multimolding materials, etc., by blending a specific polyalkylene terephthalate with a specific phosphite compound and a specific hindered phenolic compound at a specific ratio. CONSTITUTION:The objective composition is obtained by blending (A) 100 pts.wt. of a polyalkylene terephthalate (having 2-4C alkylene group) resin containing 1-40mol% comonomer unit with (B) 0.001-5 pts.wt. of one or two or more phosphite compound expressed by formula I or formula II [R<1> to R<4> are 1-25C alkyl, (substituted)aryl, etc.; R<5> is 4-33C alkylene, (substituted)arylene, etc.; Ar and Ar' are 6-35C (substituted)aryl] and (C) 0-5 pts.wt. of one or two or more hindered phenolic compounds such as 2,6-di-tert.-butyl-4-methylphenol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic polyester resin composition and a molded article obtained by molding the same, and more specifically, a polyester resin composition having extremely excellent heat stability, melt stability and high temperature long-term physical properties. It is about. INDUSTRIAL APPLICABILITY The resin composition of the present invention is suitably used as exterior parts, mechanical parts, etc. in the fields of automobiles, machines, construction, electric / electronic devices and other industries. In particular, it is excellent in processing stability at high temperatures, and has excellent adhesiveness and airtightness between resins, and therefore, it is suitably used for multiple molding materials and the like.

[0002]

2. Description of the Related Art Crystalline thermoplastic polyester resins are engineering plastics because they are excellent in mechanical properties, electrical properties and other physical / chemical properties and have good processability. Is used in a wide range of applications such as automobiles, electric and electronic parts, etc. On the other hand, in recent years, various characteristics have been required for automobiles and electric / electronic parts, and a two-body molded part in which different materials are combined has been developed as one of the methods for imparting the characteristics. As a material for use, a modified polyester having a low melting point and a low latent heat of fusion is an important material. In particular, the modified polyalkylene terephthalate copolymer modified by copolymerizing a specific amount of comonomer retains excellent mechanical, physical and chemical properties, and is excellent in low deformability, adhesion and airtightness. Therefore, it is a suitable material. However, in double molding of these modified polyalkylene terephthalate copolymers, in order to obtain adhesion strength and airtightness at the resin interface between the primary material and the secondary material, the secondary material injected in the secondary molding is used. The surface (interface) of the primary material needs to be melted. Therefore, the temperature of the molten resin in the secondary molding must be at least the melting point of the primary molding material, and in general, in order to obtain practical adhesion strength and airtightness of double molded parts, Secondary molding must be performed by raising the resin temperature of the material to 30 ° C or more higher than the melting point of the primary material, and sometimes molding resin temperature near 300 ° C is used. At the molding resin temperature of such a secondary material, the modified polyalkylene terephthalate copolymer undergoes thermal decomposition and the like, so that the moldability is impaired due to viscosity decrease and gas generation, and the adhesion strength of the molded product decreases and the modified poly This resulted in deterioration of the physical properties of the alkylene terephthalate copolymer. Further, there is a problem in long-term heat resistance due to thermal decomposition and the like. Thus, as a multi-molding material, heat resistance, melt stability, particularly suitable as a material molded at a temperature higher than the general molding temperature as a double molding material,
A resin material excellent in long-term durability has not been provided yet.

[0003]

The present inventors have found that the functional thermoplastic polyester resin has excellent heat resistance stability, melt stability, long-term durability, and excellent adhesion and airtightness between resins in multiple molding. As a result of extensive studies to obtain a composition, the present invention has been achieved. That is, the present invention is based on 100 parts by weight of a polyalkylene terephthalate (alkylene group having 2 to 4 carbon atoms) resin containing 1 to 40 mol% of a comonomer unit, a specific compound represented by the following general formula (I) or (II). 0.001 to 5 parts by weight of one or more kinds of phosphorus compounds or specific sulfur compounds and 0 to 5 parts by weight of one or more kinds of hindered phenol compounds.
The present invention relates to a thermoplastic polyester resin composition having excellent heat stability, melt stability, long-term durability, and adhesion and airtightness between resins in multiple molding.

[0004]

[Chemical 3]

(However, R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents an alkyl group having 1 to 25 carbon atoms, a substituted alkyl group, an aryl group or a substituted aryl group. , R ⁵ represents an alkylene group having 4 to 33 carbon atoms, a substituted alkylene group, an arylene group or a substituted arylene group.)

[0006]

[Chemical 4]

(However, Ar and Ar 'represent an aryl group or a substituted aryl group having 6 to 35 carbon atoms, and may be the same or different.) According to the examination by the present inventors, By adding a specific phosphorus compound or a specific sulfur compound as described above to a polyalkylene terephthalate resin containing 1 to 40 mol% of a comonomer unit, the heat resistance stability of the resin,
Melt stability and long-term durability are remarkably improved, and the decomposition of the polyester resin during the preparation of the resin composition is suppressed, so that higher temperature processing conditions can be selected during multiple molding, which is excellent. The present invention has been completed by finding that it is possible to stably manufacture a material having adhesion strength and airtightness. According to the present invention, a synergistic effect can be obtained by adding 0 to 5 parts by weight of a hindered phenol compound to 100 parts by weight of polyalkylene terephthalate in combination with the specific phosphorus compound or the specific sulfur compound as described above. And the processing stability, heat resistance stability, long-term physical properties, etc. of the resin are dramatically improved.

The polyalkylene terephthalate resin used in the present invention is polyethylene terephthalate which is a polyalkylene terephthalate obtained by polycondensation reaction of terephthalic acid or its ester forming derivative with alkylene glycol having 2 to 4 carbon atoms or its ester forming derivative. , A copolymer containing polypropylene terephthalate or polybutylene terephthalate as a main component and 1 to 40 mol% of another comonomer unit introduced thereinto. Here, the content of the comonomer unit is limited to the range of 1 to 40 mol%, particularly 4 to 35 mol in order to obtain a material having both the characteristics as the original engineering plastic and the excellent adhesion and airtightness. % Is preferred. Examples of the third component (comonomer) constituting the copolymer include isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, and dodecanedioic acid. Such known dicarboxylic acids and their alkyl, alkoxy or halogen-substituted products can be used. Also, these dicarboxylic acid compounds can be used as a copolymer component by being used for polycondensation in the form of a derivative capable of forming an ester, for example, a lower alcohol ester such as dimethyl ester.
Examples of the dihydroxy compound used as the third component for forming the copolymer are ethylene glycol, propanediol, butanediol, diethylene glycol, triethylene glycol, neopentyl glycol, hydroquinone, resorcin, dihydroxyphenyl, naphthalene. Diol, dihydroxydiphenyl ether, cyclohexanediol, 2,2-bis (4
-Hydroxyphenyl) propane, a dihydroxy compound having a relatively low molecular weight such as diethoxylated bisphenol A, and alkyl, alkoxy or halogen substitution products thereof. In the present invention, any of the polyalkylene terephthalate resins produced by polycondensation can be used as the third component with the compound as described above, and they can be used alone or in combination of two or more. In particular, aromatic dicarboxylic acid-modified polyalkylene terephthalate copolymer or alkylene glycol-modified polyalkylene terephthalate copolymer, more preferably isophthalic acid-modified polybutylene terephthalate copolymer, isophthalic acid-modified polyethylene terephthalate copolymer or ethylene glycol modified polybutylene. When a terephthalate copolymer is used, the stabilizing effect of the present invention is remarkable, and in addition, it is a material having properties as an original engineering plastic and having excellent adhesion and airtightness. It is suitable as a molding material. Further, in the present invention, a thermoplastic polyester modified by a known method such as cross-linking or graft polymerization, or a mixture of a thermoplastic polyester with another thermoplastic resin or the like depending on the purpose can be used as the base resin. The effect of the invention is exhibited. Examples of the thermoplastic resin and the like mixed with the thermoplastic polyester are polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, polyamide, polyacetal. , Polystyrene, styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-butadiene-acrylic acid (or its ester) copolymer, styrene-acrylonitrile copolymer, polycarbonate, polyurethane, fluororesin, polyphenylene oxide , Polyphenylene sulfide, polybutadiene, halogenated polyolefin, polyhalogenated vinyl, butyl rubber, silicone resin, olefinic thermoplastic elastomer (eg EPDM or ionomer), Styrene-based thermoplastic elastomer (e.g., SB
S or SEBS), urethane-based thermoplastic elastomer,
It is a polyester-based thermoplastic elastomer, a polyamide-based thermoplastic elastomer, a polyether-based thermoplastic elastomer, a multilayer graft copolymer mainly composed of polyacrylate, or a modified product thereof. Although these substances are not essential components, they can be used in combination depending on the intended properties, and the type and amount of addition can be appropriately selected.

In the present invention, in order to improve the heat resistance stability, melt stability and long-term durability of the thermoplastic polyester,
The specific phosphorus compound to be added as an essential component is represented by the following general formula (I) or (II).

[0010]

[Chemical 5]

[0011]

[Chemical 6]

In the general formula (I), R ¹ , R ² , R ³ and R ⁴ are an alkyl group having 1 to 25 carbon atoms, a substituted alkyl group, an aryl group or a substituted aryl group, which may be the same as each other. It can be different. To show these examples, methyl group, ethyl group, butyl group, octyl group, decyl group, lauryl group,
Examples thereof include tridecyl group, stearyl group, phenyl group, alkyl- and / or alkoxy-substituted phenyl group. See also R ⁵
Represents an alkylene group having 4 to 33 carbon atoms, a substituted alkylene group, an arylene group or a substituted arylene group, and examples thereof include butylene group, octylene group, phenylene group,
Naphthylene group, diphenylene group, the following formula

[0013]

[Chemical 7]

A group represented by the formula (wherein X is an oxy group, a sulfonyl group, a carbonyl group, a methylene group, an ethylidene group,
Butylidene group, isopropylene group, diazo group, etc.) and the like. Particularly preferred phosphite compounds include tetrakis (2,4-di-t-butylphenyl) -4,4'-diphenylene phosphite. In addition, the general formula (II)
In the above, Ar and Ar ′ are aryl groups or substituted aryl groups having 6 to 35 carbon atoms, and they may be the same or different. Examples of these are a phenyl group, a naphthyl group, a diphenyl group and the like, or alkyl, hydroxy and / or alkoxy substitution products thereof. To give an example of a specific compound, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6
-Di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, 4-phenoxy-9
Examples include -α- (4-hydroxyphenyl) -p-cumenyloxy-3,5,8,10-tetraoxa-4,9-diphosphaspiro [5,5] undecane. Among these, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite and bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite are particularly preferable, The effect of the present invention is remarkable.

Further, in the present invention, the specific sulfur compound added as an essential component in order to improve the heat resistance stability, melt stability and long-term durability of the thermoplastic polyester is a compound having a thioether bond. , To give an example, tetrakis [methylene-3- (dodecylthio) propionate] methane, dilauryl-3,3'-thiopropionate, dimyristyl-3,3'-thiopropionate,
Examples thereof include distearyl-3,3'-thiopropionate.

In the present invention, it is possible to use one kind or two or more kinds of these specific phosphorus compounds or specific sulfur compounds, and 0.001 to 5 parts by weight relative to 100 parts by weight of the polyalkylene terephthalate resin. It is added so as to be contained. If the amount is less than 0.001 parts by weight, sufficient heat stability and long-term physical properties cannot be obtained.
If the amount is more than the amount by weight, not only is it uneconomical, but the effect of improving heat stability and the like reaches saturation, and conversely, deterioration of moldability and reduction of strength cannot be ignored, which is not preferable. From the viewpoint of improving effects such as heat resistance stability, various physical properties, and economical efficiency, 0.01 to 1 part by weight is preferably used, and more preferably 0.03 to 0.5 part by weight is used.

In the present invention, even if the specific phosphorus compound or the specific sulfur compound as described above is added alone to the thermoplastic polyester, the heat resistance stability of the polyester is remarkably improved and a sufficient effect can be obtained. However, it is more preferable that the hindered phenol compound is further added to the polyester in order to exert a synergistic effect and further improve the heat resistance stability of the polyester.
The hindered phenolic compound used in the present invention is a phenolic compound having a bulky substituent at a position adjacent to a phenolic hydroxyl group, for example, a substituent having 4 or more carbon atoms. , 6,2-di-t-butyl-4-methylphenol, 4,4 '
-Butylidene-bis (6-t-butyl-3-methylphenol), 2,2'-methylene-bis (4-methyl-6-t)
-Butylphenol), 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,5-di-t) -Butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], octadecyl-3-
(3,5-di-t-butyl-4-hydroxyphenyl) propionate and the like, among which pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4) is preferred.
-Hydroxyphenyl) propionate] and triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] are preferable, and the effect of the present invention is remarkable. 0 to 5 parts by weight of one or more of these hindered phenol compounds are blended with 100 parts by weight of the thermoplastic polyester.

These hindered phenol compounds are
Even if it is blended alone with the thermoplastic polyester, it has little or no effect on the improvement of heat stability and the like, and a synergistic effect is produced only when it is used in combination with the above-mentioned specific phosphorus compound or specific sulfur compound. However, when the amount is more than 5 parts by weight, the improvement effect reaches saturation and is uneconomical, and conversely, strength reduction and moldability reduction are unavoidable, which is not preferable. Generally, the preferable addition amount is 1 part by weight or less, more preferably 0.5 part by weight or less.

As described above, the effects of the present invention are effective in improving the heat resistance stability, melt stability, and long-term durability of the thermoplastic polyester resin composition containing no inorganic filler, as well as glass. A marked effect is also exhibited for a composition which is reinforced and modified by adding a filler, or a composition which is blended with a flame retardant or a flame retardant aid to impart flame retardancy. The glass filler may be any of glass fiber, glass flakes, glass beads, milled fiber glass, powdered glass, and the like, and the size and shape thereof can be arbitrarily selected according to the purpose. Further, these glass fillers may have a surface treatment with a surface treatment agent or a coupling agent in order to improve the adhesion with the resin and enhance the reinforcing effect, or may be those added at the same time. good. These glass fillers can be used in combination of two or more shapes to exhibit their combined effect. As the flame retardant, organic halogen compounds, phosphorus compounds and the like are used, but aromatic bromine compounds are particularly preferable, and as the flame retardant aid,
Metal oxides and hydroxides such as antimony trioxide, antimony halide, aluminum hydroxide and magnesium hydroxide are used. Addition of such a flame retardant and a flame retardant auxiliary generally impairs the heat resistance stability of the thermoplastic polyester and tends to accelerate the deterioration under high temperature. Therefore, regarding the flame retardant polyester composition, the heat resistance stability is particularly high. Although there is an urgent need for improvement, the effect of the present invention is remarkably recognized and particularly effective for such a flame-retardant polyester.

Further, since the polyalkylene terephthalate resin constituting the composition of the present invention is a copolymer containing a comonomer unit, when it is used as an injection molding material, the molding cycle is lowered and the mold releasing is performed under normal molding conditions. Failure can occur especially when using a copolymer with a high content of comonomer units. In order to solve this, it may be preferable to use any one of a nucleating agent, a plasticizer, and a releasing agent, or to use them in combination. As the nucleating agent, 0.001 to 5% by weight of known organic substances and inorganic substances may be added. Specific examples include boron nitride, kaolin, talc, and metal salts of olefin-acrylic acid copolymers, which may be used alone or in combination of two or more. As the plasticizer, known benzoic acid ester, phosphoric acid ester compounds and the like are used alone or in combination of two or more kinds. As the release agent, ester or amide compounds of higher fatty acid C ₉ -C _30, or a polyethylene wax are used in common or two or more.

Further, the composition of the present invention may further contain a known substance which is added to a general thermoplastic resin or a thermosetting resin depending on the purpose. For example, various stabilizers for light resistance, weather resistance, colorants, antistatic agents,
Surfactants, lubricants, etc., or carbon fibers, metal fibers, boron fibers, potassium titanate, ceramics, mica, clay, talc, asbestos, highly dispersible silicates,
Quartz powder, silica sand, wollastonite, carbon black, graphite, various metal powder, metal foil, silicon carbide,
Fiber-like, plate-like, granular, powdery inorganic compounds and organic compounds such as boron nitride and silicon nitride are included.

The composition of the present invention can be easily prepared by a known method generally used as a conventional resin composition preparation method. For example, after mixing each component, kneading and extruding with an extruder to prepare pellets, and then molding, a pellet having a different composition is prepared once, and the pellets are mixed in a predetermined amount and subjected to molding, and after molding. Any method such as a method of obtaining a molded product having a target composition, a method of directly charging one or more of each component into a molding machine, and the like can be used. Further, the specific phosphorus compound or the specific sulfur compound, which is an essential component of the present invention, and the hindered phenol compound in some cases, are added in whole or in part at any time during the production process of the thermoplastic polyester and the processing process. It is possible to improve the efficiency of the polymerization reaction, especially when it is added to the reaction system during the progress of the polycondensation reaction by adding it at the monomer stage or relatively early in the polycondensation reaction, because decomposition during polymerization is suppressed. Can be done well. In particular, when polycondensation in the molten state is carried out for a long time for the purpose of obtaining a polyester having a high molecular weight, or when the molten reaction product is once solidified and solid phase polymerization is carried out for a long time, the above-mentioned components of the present invention are reacted. The presence in the system is particularly effective for preventing deterioration during the reaction and for obtaining a high molecular weight polyester, and for such purpose, the above-mentioned essential components are preferably added before polycondensation. In the present invention, such a method is also suitably used as a method for preparing a resin composition.

The resin composition of the present invention can be obtained by a so-called multiple molding method by using a polyester-based polymer, a polyamide-based polymer, a polycarbonate-based polymer, a polyphenylene oxide-based polymer, a polyacetal, a styrene-based copolymer (AS, ABS, etc.). ), Olefin-based thermoplastic elastomer (EPDM or ionomer), styrene-based thermoplastic elastomer (SBS, SBES, etc.), urethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer or polyamide-based thermoplastic elastomer. By the combination, a composite molded article having new characteristics in addition to the characteristics of the polyester resin can be obtained. As the molding method, known molding methods such as injection molding, compression molding, extrusion molding and the like are applied. Further, the resin composition of the present invention can be used as a primary material and / or a secondary material molded product in multiple molding, and is appropriately selected and used depending on the shape, structure or intended use of the molded product.

[0024]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The evaluation of heat resistance stability and the like was made by appropriately selecting from the following methods. Heat stability of test pieces (long-term physical properties): Using the resin compositions according to each of the Examples and Comparative Examples, an ASTM tensile test piece and a lithographic plate for measuring hue were molded with an injection molding machine set at a cylinder temperature of 250 ° C. , Tensile strength (initial value) and hue (initial value)
Was measured. Then, the test piece was placed in a gear oven set at 180 ° C., heat-treated under circulating hot air, treated for a certain period of time, and then evaluated for tensile strength and hue change.

[0026]

[Equation 1]

Heat resistance stability under melting After the resin was retained in the cylinder of a molding machine set at 260 ° C. for 30 minutes, a tensile test piece was molded and the tensile strength was measured. The heat resistance stability was calculated by the following formula.

[0028]

[Equation 2]

Examples 1 to 8, Comparative Examples 1 to 3 MI modified by copolymerizing 5% by mole of DMI (dimethyl isophthalate) has an MI of 45 (according to ASTM D 1238, 23
The specific phosphorus compound or the specific sulfur compound shown in Table 1 was added to DMI-modified PBT (melting point 215 ° C.) at 5 ° C., load 2.16 kg (measured value) at various concentrations, and a twin-screw extruder was used. To prepare a pelletized composition. Next, a test piece was produced by injection molding using this pellet, and the strength retention rate and the hue change due to the heat treatment were evaluated by the method described above. On the other hand, for comparison, similar tests were carried out for a specific phosphorus compound, a specific sulfur compound not added, and a phosphorus compound other than the present invention. The results of Examples and Comparative Examples are shown together in Table 1.

[0030]

[Table 1]

Note) * 1: Tetrakis (2,4-di-t-butylphenyl) -4,
4'-diphenylene phosphite * 2: bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite * 3: bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol Diphosphite * 4: 4-phenoxy-9-α- (4-hydroxyphenyl) -p-cumenyloxy-3,5,8,10-tetraoxa-
4,9-Diphosphaspiro (5,5) undecane * 5: Tetrakis [methylene-3- (dodecylthio) propionate] methane Examples 9-11, Comparative Examples 4-5 Based on the formulations of Examples 2, 5 and 8 above. Then, a hindered phenolic compound was further added to the mixture and evaluated in the same manner as in the above-mentioned Examples. On the other hand, for comparison, those in which a specific phosphorus compound, a specific sulfur compound and a hindered phenol compound were not added (Comparative Example 1) and those in which only a hindered phenol compound was added were similarly evaluated. The results are shown in Table 2.

[0032]

[Table 2]

Note) * 1: Tetrakis (2,4-di-t-butylphenyl) -4,
4'-diphenylene phosphite * 2: pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] * 3: bis (2,4-di-t-butyl) Phenyl) pentaerythritol diphosphite * 4: triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] * 5: tetrakis [methylene-3- (dodecylthio) propionate] Methane Examples 12-14, Comparative Examples 6-7 MI modified by copolymerizing 12.5 mol% of DMI (dimethyl isophthalate) is 45 (according to ASTM D 1238,
DMI-modified PBT measured at 235 ° C and a load of 2.16kg)
(Melting point 205 ° C.) 40 parts by weight of glass fiber was added to 100 parts by weight, further, a specific phosphorus compound was added in Examples 12 and 13, and a specific phosphorus compound and a hindered phenol compound were used in combination in Example 14. The ingredients were blended and evaluated in the same manner as in the above example. On the other hand, for comparison, those in which both the phosphorus compound and the hindered phenol compound were not added, and those in which only the hindered phenol compound was added and the phosphorus compound was not added were evaluated in the same manner. The results are shown in Table 3.

[0034]

[Table 3]

Note) * 1: Tetrakis (2,4-di-t-butylphenyl) -4,
4'-diphenylene phosphite * 2: bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite * 3: pentaerythrityl-tetrakis [3- (3,5-di-t-butyl- 4-Hydroxyphenyl) propionate] Examples 15-17, Comparative Examples 8-9 MI modified by copolymerizing 17.5 mol% of ethylene glycol is 45 (according to ASTM D 1238, 235 ° C, load 2.1).
40 parts by weight of glass fiber was added to 100 parts by weight of ethylene glycol-modified PBT (melting point 205 ° C.) (measured value at 6 kg), and further, a specific phosphorus compound shown in Table 4 or a specific phosphorus compound and a hindered phenol The compounds of the present invention were added together and evaluated in the same manner as in the above-mentioned Examples. On the other hand, for comparison, the same evaluation was performed for the case where both the phosphorus compound and the hindered phenol compound were not added, and the case where only the hindered phenol compound was added and the phosphorus compound was not added. The results are shown in Table 4.

[0036]

[Table 4]

Note) * 1: Tetrakis (2,4-di-t-butylphenyl) -4,
4'-diphenylene phosphite * 2: bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite * 3: pentaerythrityl-tetrakis [3- (3,5-di-t-butyl- 4-Hydroxyphenyl) propionate] Examples 18 to 21, Comparative Examples 10 to 12 Using each composition shown in Table 5, 80 mm as a primary molded product
A flat plate having a corner and a thickness of 2 mm was formed. Next, this flat plate is 80 mm
It is mounted in a die cavity with a square shape and a thickness of 4 mm, and each composition shown in Table 5 is used as a secondary material to carry out secondary molding at a resin temperature of 260 ° C or 280 ° C to produce a flat-plate composite molded article. Then, the peel strength at the interface was measured. The peel strength was measured by cutting the composite molded product to a width of 10 mm, forcibly peeling the joint interface at one end with a knife for a certain length, and setting each of them on the fixture of the tensile tester to pull and peel. The maximum load generated was taken as the peel strength. In addition, during molding, the phenomenon of beating from the nozzle was visually observed. In addition, the heat resistance stability of the secondary molding material under melting was evaluated in the same manner as in the above example. Furthermore, the flat composite molding obtained is exposed to an atmosphere of 130 ° C for 60 minutes, then immersed in water of 0 ° C for 60 minutes, taken out of the water and left at room temperature for 15 minutes. Heating / cooling cycle Was repeated 50 times, and then the ink was dipped in a highly penetrable ink, and after the ink dries, the adhesive surface was broken and the ink penetration state was visually observed. The results are shown in Table 5.

[0038]

[Table 5]

Note) * 1: Kind of polyester resin (A): Modified polybutylene terephthalate copolymer (MI45) (B) modified by copolymerizing 12.5 mol% of dimethyl isophthalate: 17.5 mol% of ethylene glycol Modified polybutylene terephthalate copolymer (MI45) (C) modified by copolymerization: Modified polybutylene terephthalate copolymer (MI45) (D): Poly modified by copolymerizing 42 mol% of dimethyl isophthalate Butylene terephthalate resin * 2: Phosphorus compound Tetrakis (2,4-di-t-butylphenyl) -4,4'-
Diphenylene phosphite * 3: Hindered phenol compound pentaerythrityl-tetrakis [3- (3,5-di-t
-Butyl-4-hydroxyphenyl) propionate] * 4: sulfur compound tetrakis [methylene-3- (dodecylthio) propionate] methane

[0040]

As is apparent from the above description and the examples, the effect of the present invention can be obtained by adding a polyalkylene terephthalate resin containing 1 to 40 mol% of a comonomer unit to the above general formula (I) or (II). By compounding the specific phosphorus compound or the specific sulfur compound represented, molding processing stability, heat resistance stability and long-term physical properties of the polyester resin are remarkably improved, and further by adding a hindered phenol compound in combination. A synergistic effect is exhibited, and it becomes possible to obtain a thermoplastic polyester resin composition having dramatically improved molding processing stability, excellent heat stability, and long-term physical properties that could not be achieved by conventional methods. It was As described above, the composition of the present invention is excellent in molding processing stability at high temperature in addition to long-term heat stability, so that a wide range of processing conditions can be selected and high adhesion strength and airtightness are required. It is preferably used for multiple molding materials and the like.

Claims (6)

[Claims] 1. A phosphine represented by the following general formula (I) or (II) per 100 parts by weight of a polyalkylene terephthalate (alkylene group having 2 to 4 carbon atoms) resin containing 1 to 40 mol% of a comonomer unit. A polyester resin composition comprising 0.001 to 5 parts by weight of one or more phyto compounds and 0 to 5 parts by weight of one or more hindered phenol compounds. [Chemical 1] (However, R ¹ , R ² , R ³ and R ⁴ may be the same or different, and may be an alkyl group having 1 to 25 carbon atoms, a substituted alkyl group, an aryl group or a substituted aryl group, and R ⁵ Represents an alkylene group having 4 to 33 carbon atoms, a substituted alkylene group, an arylene group or a substituted arylene group.) (However, Ar and Ar 'represent an aryl group or a substituted aryl group having 6 to 35 carbon atoms and may be the same or different.) 2. 0.001 to 5 parts by weight of one or more thioether compounds per 100 parts by weight of a polyalkylene terephthalate (alkylene group having 2 to 4 carbon atoms) resin containing 1 to 40 mol% of a comonomer unit. And 0 to 5 parts by weight of one or more of hindered phenolic compounds. 3. A polyalkylene terephthalate resin,
The polyester resin composition according to claim 1 or 2, which is a polybutylene terephthalate, polypropylene terephthalate or polyethylene terephthalate copolymer containing 1 to 40 mol% of an isophthalic acid residue or an ethylene glycol residue. 4. An inorganic filler is added to the total amount of the composition in an amount of 1
The polyester resin composition according to any one of claims 1 to 3, containing 40 to 40% by weight. 5. A molded product obtained by molding the polyester resin composition according to any one of claims 1 to 4. 6. A molded product obtained by multiple molding of the polyester resin composition according to claim 1 by an injection molding method.