JP2013067746A - Inorganic-reinforced polyester resin composition and molded article made of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic-reinforced polyester resin composition that has high fluidity, can be injection-molded at a low pressure and satisfies all of mechanical properties, long term durability and enhanced productivity by efficiently blocking a terminal carboxylic acid, which causes hydrolysis, of a low-molecular-weight polyester with a reactive compound.SOLUTION: The inorganic-reinforced polyester resin composition comprises (1) a polyester, (2) an unmodified polyolefin, (3) an inorganic particulate filler, (4) an inorganic reinforcing fiber and (5) a reactive compound in a mass ratio of (1)/(2)/(3)/(4)/(5) of 100/(5-15)/(0.3-3)/(1-50)/(0.5-3), where the polyester (1) is a polybutylene terephthalate having a reduced viscosity of at least 0.40 dl/g and at most 0.65 dl/g and the reactive compound (5) is a polycarbodiimide.

Description

  The present invention relates to an inorganic reinforced polyester resin composition suitable for injection molding. Specifically, the present invention relates to an inorganic reinforced polyester resin composition having good resin fluidity in injection molding and having long-term durability, high-temperature durability, hydrolysis resistance, and heat shock resistance.

  In recent trend of resinization from metals, engineering plastics such as polyester, polyamide and polyphenylene sulfide are used particularly for applications requiring low cost and heat resistance. These engineering plastics have good mechanical properties and high long-term durability, and are used for electrical parts, home appliances, automobile interior parts and exterior parts, and housing equipment. In recent years, there has been a growing demand for lighter and thinner parts for electric home appliances from the viewpoint of improving fuel efficiency in parts for automobile interior and exterior parts as the parts become smaller. Since the engineering plastic has high crystallinity, there is a problem that it is difficult to sufficiently fill the thin wall portion with a resin composition having a high melt viscosity. In order to perform sufficient filling, a high injection pressure is required, and excessive pressure causes burrs and deformation of the molded product. This method has a problem that a large mold clamping force that overcomes a high injection pressure is required, the size of the injection molding machine needs to be increased, and the production cost increases.

  As a method of filling the thin-walled part with resin, there is a method of increasing the fluidity by reducing the molecular weight of engineering plastics. This is not desirable. In particular, polyester resins are known to undergo hydrolysis from terminal carboxylic acids, and a method for improving hydrolysis resistance by applying a carboxylic acid end-capping treatment with an epoxy compound or the like has been proposed (patented) Reference 1). However, in this method, since the reactivity of the epoxy compound is poor, in order to sufficiently block the carboxylic acid terminal, it is necessary to add an epoxy compound in excess of the amount of the carboxylic acid terminal. There are problems of environmental concern due to gas generated sometimes, and productivity reduction due to crystallinity deterioration due to epoxy compound.

  In addition, a method has also been proposed in which low-crystalline or non-crystalline plastic is melted and kneaded into the engineering plastic to inhibit crystallinity and flow into a thin portion (see Patent Document 2 and Patent Document 3). There are also problems such as a decrease in durability at high temperatures due to a decrease in crystallinity and a deterioration in production cycle due to an increase in cooling time.

  In addition, a method for improving fluidity by adding a fluidity imparting agent or a plasticizer to the engineering plastic has been proposed (Patent Document 4, Patent Document 5). Since it precipitates on the surface of a molded product or inhibits crystallization of engineering plastics, there are problems such as a decrease in durability at high temperatures and a deterioration in production cycle due to an increase in cooling time.

JP 2002-220454 A JP-A-6-99453 JP 11-279383 A JP-A 61-163957 JP-A-5-214222

  The present invention has been made to solve the above problems, and the object of the present invention is to efficiently block a terminal carboxylic acid that causes hydrolysis by using a low molecular weight polyester as a reactive compound, To provide a polyester resin composition that can be injection-molded at a low pressure and further has a mechanical property, long-term durability, and improved productivity by thickening a low molecular weight polyester with a reactive compound. is there.

  In order to achieve the above object, the present inventors have intensively studied and have proposed the following invention. That is, the present invention is as follows.

[1] (1) Polyester, (2) Unmodified polyolefin, (3) Inorganic particulate filler, (4) Inorganic reinforcing fiber, and (5) Polycarbodiimide as a reactive compound in a mass ratio of (1) / ( 2) / (3) / (4) / (5) = 100/5 to 15 / 0.3 to 3/1 to 50 / 0.5 to 3 and (1) polyester has a reduced viscosity of 0 An inorganic reinforced polyester resin composition, which is a polybutylene terephthalate having a viscosity of 40 dl / g or more and 0.65 dl / g or less.

[2] The (2) unmodified polyolefin is polyethylene or a nonpolar ethylene copolymer, the density is 0.95 g / cm ³ or less, and (2) the melt flow rate at 190 ° C. and 2160 g of the polyolefin is 60. (G / 10 minutes) or more, The inorganic reinforced polyester resin composition according to [1].

[3] The inorganic reinforced polyester resin composition according to any one of [1] to [2], wherein the (3) inorganic particulate filler is talc having an average particle size of 5 μm or less.

[4] The inorganic reinforced polyester resin composition according to any one of [1] to [3], wherein the (4) inorganic reinforcing fiber is a glass fiber.

[5] The number average molecular weight of the (5) polycarbodiimide is 500 to 10,000, and the carbodiimide group amount is 100 to 10,000 equivalent / ton, according to any one of [1] to [4] Inorganic reinforced polyester resin composition.

[6] A molded article obtained from the inorganic reinforced polyester resin composition according to any one of [1] to [5].

  According to the present invention, since a low molecular weight polyester is used, a high injection pressure and a large molding machine associated therewith are not required, and further, a polyester-terminated carboxylic acid is blocked with a reactive compound, and a long-term durability and resistance to a thickening reaction. An inorganic reinforced polyester resin composition having hydrolyzability can be provided. Furthermore, in addition to these characteristics, it is possible to improve productivity by excellent mold release from the mold and shortening the cooling time. This provides a material that sufficiently satisfies various performances such as mechanical properties, high temperature durability, high temperature and humidity resistance, heat shock resistance, and productivity as an inorganic reinforced polyester resin composition having a complicated shape and thin wall It becomes possible.

[(1) Polyester]
(1) Polyester used in the present invention is a polybutylene terephthalate resin mainly composed of butylene terephthalate as a repeating unit. A polybutylene terephthalate copolymer containing polybutylene terephthalate and / or 80 mol% or more of butylene terephthalate units is used. Examples of the copolymerized glycol component include ethylene glycol, propylene glycol, butanediol, hexamethylene glycol, neopentyl glycol, cyclohexane dimethanol, diethylene glycol, polyethylene glycol, polytetramethylene glycol, and polylactone. As the acid component, a known acid component can be copolymerized. For example, naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, adipic acid, sesic acid and the like are used. When the copolymerization component exceeds 20 mol%, the heat resistance and crystallinity are lowered, which is not preferable for this application.

  (1) The reduced viscosity of the polyester used in the present invention is 0.40 dl / g or more and 0.65 dl / g or less when measured by the measurement method described later. The reduced viscosity is preferably 0.45 dl / g or more and 0.60 dl / g or less. If it is less than 0.40 dl / g, (5) various durability is low even in the resin thickened by the reactive compound, and if it exceeds 0.65 dl / g, (5) the thickening reaction of the polyester by the reactive compound occurs. It may progress and liquidity may be insufficient. The acid value is preferably 40 eq / t or less. The (5) reactive compound described later blocks the terminal carboxyl group of the polyester to improve hydrolysis resistance. (5) In order to avoid gelation due to excessive addition of the reactive compound, 25 eq / t or less Particularly preferred.

[(2) Unmodified polyolefin]
(2) The unmodified polyolefin used in the present invention is preferably an ultra-low density unmodified polyolefin having a density of 0.95 g / cm ³ or less and a melt flow rate at 190 ° C. and 2160 g of 60 (g / 10 min) or more. . By using such an ultra-low density unmodified polyolefin, it is possible to easily finely disperse and mix with the originally incompatible polyester, and does not require special kneading equipment, and a good resin composition for injection molding. Can be obtained. In addition, the low density and low crystallinity appropriately act on the temporal relaxation of the residual stress generated in the polyester during the injection molding. Further, the relaxation of the residual stress appropriately acts on the relaxation of the crack of the molded article at the time of heat shock such as high temperature to low temperature / low temperature to high temperature.
In modified polyolefins such as glycidyl-modified and maleic acid-modified, (1) not only does the viscosity increase by reacting with polyester and causes a decrease in fluidity, but also (5) reaction with reactive compounds occurs. Therefore, (5) sufficient reaction with the carboxylic acid terminal of (1) polyester by the reactive compound does not proceed, which causes a decrease in hydrolysis resistance.
The (2) unmodified polyolefin having such characteristics is particularly preferred in that polyethylene or apolar ethylene copolymer is readily available, inexpensive, and does not adversely affect hydrolysis resistance. Specific examples include ultra low density polyethylene, linear low density polyethylene, ethylene propylene elastomer, and ethylene-butene copolymer. Among these, ultra-low density polyethylene and ethylene and other α-olefin copolymers are preferable.

  Moreover, the compounding quantity of (2) unmodified polyolefin used for this invention is (1) / (2) = 100 / 5-15 by mass ratio with respect to (1) polyester. (2) When the unmodified polyolefin is less than 5 parts by mass, (1) it is difficult to relax the strain energy by crystallization of the polyester or enthalpy relaxation, and thus the heat shock resistance tends to be lowered. (2) When unmodified polyolefin is blended in an amount exceeding 15 parts by mass, the phase separation between polyester and unmodified polyolefin causes a significant decrease in mechanical properties, moldability such as delamination during injection molding, and cooling time. There may be adverse effects such as an increase or an increase in production cycle.

[(3) Inorganic particulate filler]
The (3) inorganic particulate filler used in the present invention is an inorganic crystal nucleating agent. Among these, talc having an average particle diameter of 5 μm or less is preferable. Even if talc is used as it is, a sufficient effect can be obtained, but talc may be subjected to a polyester surface treatment. This is because the surface treatment improves the affinity with the polyester resin and improves the toughness of the polyester resin. These talcs are effective in shortening the cooling time because (1) the crystallization of the polyester is promoted and (1) the crystallization temperature of the polyester is increased. In addition, (2) the addition of unmodified polyolefin causes a decrease in high-temperature rigidity, and deformation occurs due to protrusion from the mold immediately after injection molding, resulting in a problem of increased cooling time. It has the effect of improving, suppressing deformation at the time of protrusion, and shortening the cooling time. Here, the average particle diameter of talc is more preferably 4 μm or less. This is because if the average particle size exceeds 5 μm, a large amount of addition is required to obtain an effect as a crystal nucleating agent, which causes a reduction in the toughness of the molded product.

  The compounding ratio of (1) polyester and (3) inorganic particulate filler in the resin composition of the present invention is (1) / (3) = 100 / 0.3-3 in mass ratio. (3) If the amount of the inorganic particulate filler is more than 3 parts by mass, the mechanical properties are inferior, and particularly the impact resistance and the bending deflection properties may be lowered. On the other hand, when (3) the inorganic particulate filler is less than 0.3 part by mass, the effect as a crystal nucleating agent is poor, and the effect of improving the high temperature rigidity is not observed.

[(4) Inorganic reinforcing fiber]
The (4) inorganic reinforcing fiber used in the present invention has an effect of improving the mechanical strength of the polyester resin composition. Among these, glass fiber is preferable. As the cross-sectional shape of the glass fiber, a glass fiber having a circular cross section and a non-circular cross section can be used.

  The compounding ratio of (1) polyester and (4) inorganic reinforcing fiber in the resin composition of the present invention is (1) / (4) = 100 / 1-50 in mass ratio. (4) When there are more inorganic reinforcement fibers than 50 mass parts, there exists a tendency for a moldability to fall. On the other hand, when (4) the inorganic reinforcing fiber is less than 1 part by mass, the mechanical strength is not sufficiently improved. (4) The inorganic reinforcing fiber is preferably 20 to 40 parts by mass.

[(5) Reactive compound]
The reactive compound (5) used in the present invention imparts long-term durability and hydrolysis resistance by blocking the polyester terminal carboxylic acid, and a thickening reaction, and polycarbodiimide is most suitable. Among polycarbodiimides, by containing a compound having a carboxylic acid group-reactive group and a hydroxyl group-reactive group in one molecule, the terminal carboxylic acid that reacts with the terminal carboxylic acid of the polyester and causes hydrolysis is efficiently produced. The polyester thickening reaction can be advanced while blocking well.
Examples of the functional group that reacts with carboxylic acid include glycidyl group, oxazoline group, oxetane group, carbodiimide group, etc., but general glycidyl group-containing compounds, oxazoline group-containing compounds, oxetane group-containing compounds do not react quickly, In order to generate sufficient hydrolysis resistance, it is necessary to add more than the equivalent amount of terminal carboxylic acid in the polyester. Addition of an excessive amount of reactive compound not only lowers the crystallization temperature of the polyester, but also causes problems such as contamination due to volatilization during drying and precipitation on the surface of the molded product, and causes gelation by the reactive compound. It becomes. On the other hand, carbodiimide compounds have a faster reaction than glycidyl groups, oxazoline groups, and oxetane groups, and are highly preferable for use with terminal carboxylic acids. The functional group that reacts with a hydroxyl group is different from the functional group that reacts with a carboxylic acid, and examples thereof include an isocyanate group and an acid anhydride group, and an isocyanate group is particularly preferred from the viewpoint of reactivity. As a result of extensive studies, the compound having a carboxylic acid group-reactive group and a hydroxyl group-reactive group in one molecule is most preferably a compound having a carbodiimide group and an isocyanate group in one molecule.
The purpose of adding carboxylic acid group-reactive groups and hydroxyl-reactive groups in one molecule is to make these functional groups easy to react with polyester, and polyester resins with small molecular weights are reactive with terminal carboxylic acids. By linking with a compound, it is possible to improve other long-term durability by increasing the viscosity while efficiently eliminating the terminal acid that causes hydrolysis.

  Although it does not specifically limit as polycarbodiimide used by this invention, Aliphatic carbodiimide, alicyclic carbodiimide, aromatic carbodiimide, and these copolymers can be used. For example, bis (dipropylphenyl) carbodiimide, dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, di-t-butylcarbodiimide, dioctylcarbodiimide, diphenylcarbodiimide, di-β-naphthylcarbodiimide, t-butylisopropylcarbodiimide, etc. Examples thereof include carbodiimide, polycarbodiimide having two or more —N═C═N— structures in one molecule, monocarbodiimide having an isocyanate group at the terminal, and polycarbodiimide having an isocyanate group at the terminal. As the polycarbodiimide, known ones prepared by decarbonization of diisocyanate compounds can be used (US Pat. No. 2,941,956, Japanese Examined Patent Publication No. 47-3279, J. Org. Chem., 28, 2069-2075 (1963). ), Chemical Review 1981, Vol. 81, No. 4, 619-621).

  The diisocyanate used is 4,4-diphenylmethane diisocyanate, 4,4-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate. Isocyanate, 1,5-naphthylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, 1,3,5-tri Isopropylphenylene-2,4-diisocyanate or the like may be used alone or in combination of two or more. Come. Further, a branched structure may be introduced, or a functional group other than a carbodiimide group or an isocyanate group may be introduced by copolymerization. Furthermore, the degree of polymerization can be controlled and the terminal isocyanate can be blocked by blocking part or all of the terminal isocyanate. As the end-capping agent, monoisocyanate compounds such as phenyl isocyanate, tris isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate, -OH group, -COOH group, -SH group, -NH-R (R is hydrogen) A compound having an atom or an alkyl group) can be used. When all the terminal isocyanates are blocked, it is necessary to introduce a hydroxyl-reactive group different from the isocyanate group. Commercially available products include the Starbucks series from Rhein Chemie, the Carbolite series from Nisshinbo, Cosmonate LK, Cosmonate LL, BASF INOAC, Lupranate MM-103 from polyurethane. Etc.

  The compound having a carboxylic acid group-reactive group and a hydroxyl group-reactive group in one molecule has a high molecular weight from the viewpoint of volatility, and has a number average molecular weight of 200 or more, preferably 400 or more, more preferably 500 or more and 10,000 or less. It is. Further, the number of carboxylic acid reactive groups is not particularly limited, but is preferably 100 to 10,000 equivalent / ton from the viewpoint of reactivity, and the lower limit is more preferably 500 equivalent / ton or more, and still more preferably 1000 equivalent / ton or more. The hydroxyl reactive group is 1 equivalent / ton.

  The compounding ratio of (1) polyester and (5) reactive compound in the resin composition of the present invention is (1) / (4) = 100 / 0.5-3 in mass ratio. If the amount is less than 0.5 parts by mass, the amount is not sufficient to block the terminal carboxylic acid. On the other hand, if the amount exceeds 3 parts by mass, the functional group is excessive and the polyester may be gelled.

As a method of determining the composition and composition ratio of the polyester resin composition used in the present invention, it is also possible to calculate from a proton integration ratio of ¹ H-NMR measured by dissolving a sample in a solvent such as deuterated chloroform. .

  The (1) polyester production method of the present invention may be a known method. For example, the esterification reaction of the above dicarboxylic acid and diol component at 150 to 250 ° C., followed by 230 to 300 ° C. while reducing the pressure. The desired polyester can be obtained by polycondensation with. Alternatively, the target polyester is obtained by transcondensation at 230 ° C. to 300 ° C. under reduced pressure after a transesterification reaction at 150 ° C. to 250 ° C. using a derivative such as dimethyl ester of dicarboxylic acid and a diol component. Can do.

  Furthermore, when the resin composition of the present invention requires durability at a high temperature for a long time, it is preferable to add an antioxidant. For example, as a hindered phenol, 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 1,1,3-tri (4-hydroxy-2-methyl- 5-t-butylphenyl) butane, 1,1-bis (3-t-butyl-6-methyl-4-hydroxyphenyl) butane, 3,5-bis (1,1-dimethylethyl) -4-hydroxy- Examples thereof include benzenepropanoic acid, pentaerythritol tetrakis (3,5-di-t-butyl-4-hydroxyphenyl) propionate, and the phosphorous-based 3,9-bis (p-nonylphenoxy) -2 , 4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane, 3,9-bis (octadecyloxy) -2,4,8,10-tetraoxa 3,9-di-phosphatonin spiro [5.5] undecane, tri (mono-nonylphenyl) phosphite, tri phenoxy phosphine include isodecyl phosphite. These can be used alone or in combination. The addition amount is preferably 0.1% or more and 5% or less on a mass basis. If it is less than 0.1%, the effect of preventing thermal deterioration may be poor. If it exceeds 5%, the appearance of the molded product due to the bleeding of the additive may be adversely affected.

  Various other additives can be blended in the resin composition of the present invention. As additives, resins, inorganic fillers, stabilizers, UV absorbers, and anti-aging agents other than those of the present invention that are widely used as additives for thermoplastic adhesives are within the range that does not impair the characteristics of the present invention. Can be added.

  As the inorganic filler, calcium carbonate, zinc oxide, titanium oxide, clay, bentonant, fumed silica, silica powder, mica and the like can be blended in an amount of 40 parts by weight or less with respect to 100 parts by weight of the resin composition of the present invention. .

Other additives include crystal nucleating agents such as various metal salts, coloring pigments, inorganic and organic fillers, tackiness improvers, quenchers, metal deactivators, UV absorbers, HALS, and other stabilizers. An agent, a silane coupling agent, a flame retardant, etc. can also be added.
The resin composition of the present invention is a total of (1) polyester, (2) unmodified polyolefin, (3) inorganic particulate filler, (4) inorganic reinforcing fiber, and (5) reactive compound, and is 70% by mass or more. Preferably. The total of (1) to (5) is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more.

  As a method for producing the resin composition of the present invention, the polyester of the present invention and polyolefin, polycarbodiimide, talc and the like are usually used as a single-screw or biaxial screw-type melt kneader, or a typical kneader-type heater. Manufactured using a thermoplastic resin mixer and subsequently pelletized by a granulation process.

  In order to describe the present invention in more detail, examples are given below, but the present invention is not limited to the examples. In addition, each measured value described in the Example is measured by the following method.

Melting point:
Using a differential scanning calorimeter “DSC220” manufactured by Seiko Denshi Kogyo Co., Ltd., put 5 mg of measurement sample into an aluminum pan, seal it with a lid, and hold it at 250 ° C. for 5 minutes to completely melt the sample. Then, it was quenched with liquid nitrogen, and then measured from -150 ° C. to 250 ° C. at a rate of temperature increase of 20 ° C./min. The endothermic peak of the obtained curve was taken as the melting point.

Reduced viscosity:
0.10 g of sufficiently dried polyester resin was dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio 6/4) and measured at 30 ° C. with an Ubellose viscometer.

Acid value:
A 0.2 g sample was precisely weighed, dissolved in 20 ml of chloroform, and titrated with 0.01 N potassium hydroxide (ethanol solution). Phenolphthalein was used as an indicator.

density:
Measured according to JIS K 7112.

Example of polyester production (Polyester A)
100 parts by mass of terephthalic acid, 100 parts by mass of 1,4-butanediol, and 0.1 parts by mass of tetrabutyl titanate were added to a reaction vessel equipped with a stirrer, a thermometer, and a condenser for distillation, and the temperature was 170 to 220 ° C. The esterification reaction was performed for 2 hours. After completion of the esterification reaction, 0.8 parts by mass of hindered phenolic antioxidant “Irganox 1330” (manufactured by Ciba Specialty Chemicals Co., Ltd.) was added and the temperature was raised to 255 ° C., while the pressure in the system was slowly reduced. Then, a polycondensation reaction was performed at 255 ° C. over 60 minutes to obtain a polyester resin (A). The melting point of this polyester resin (A) was 225 ° C., the reduced viscosity was 0.45 dl / g, and the acid value was 25 eq / t.
(Polyester B)
A transesterification reaction and a polycondensation reaction were carried out in the same manner as for polyester A to obtain a polyester resin (B). The polyester resin (B) had a melting point of 225 ° C., a reduced viscosity of 0.60 dl / g, and an acid value of 25 eq / t.
(Polyester C)
A transesterification reaction and a polycondensation reaction were carried out in the same manner as for polyester A to obtain a polyester resin (C). The polyester resin (C) had a melting point of 225 ° C., a reduced viscosity of 0.90 dl / g, and an acid value of 25 eq / t.

Example 1
100 parts by mass of the polyester (A) obtained in the above production example of polyester and ultra low density polyethylene (CX-5508 manufactured by Sumitomo Chemical Co., Ltd., density 0.90 g / cm ³ melt flow rate 75 g / 10 min) as polyolefin. 10 parts by mass, as inorganic particulate filler, 1.0 part by weight of micron white 5000A (manufactured by Hayashi Kasei Co., Ltd., average particle size 4 μm), 30 parts by weight of glass fiber as inorganic reinforcing fiber, and carbodiimide as reactive compound 0.8 parts by mass of LA-1 (polycarbodiimide manufactured by Nisshinbo Co., Ltd.) was kneaded and pelletized at 240 ° C. with a twin screw extruder having three kneading zones. The following evaluation was performed using this pellet. The results are shown in Table 1.

Injection pressure evaluation:
The pellets were molded using an injection molding machine. An electric injection molding machine EC-100N (manufactured by Toshiba Molding Machinery) was used as the injection molding machine. The molding temperature at this time was 250 to 260 ° C. from the bottom of the hopper to the nozzle tip, and the mold temperature was 80 ° C.
The injection pressure was evaluated from the maximum injection pressure when a molded product having a size of 128 mm × 13 mm and a thickness of 1.6 mm (gate size: 1 mm × 3 mm, thickness: 1.0 mm) was injection molded.

High-temperature rigidity evaluation The evaluation was performed from the bending elastic modulus at 100 ° C of the molded product during the injection molding. The bending elastic modulus was measured using a UTM-I-5000 manufactured by ORIENTEC Co., Ltd., with a span distance of 40 mm and a speed of 10 mm / min.

Hydrolysis resistance evaluation:
The molded product obtained by the above injection molding was evaluated from the bending strength retention after 1000 hours of treatment at a temperature of 80 ° C. and a humidity of 95%.
○: 90% or more △: 80% or more and less than 90% ×: less than 80%

Heat aging test:
The molded product obtained by the injection molding was evaluated from the bending strength retention after 1000 hours of treatment at a temperature of 150 ° C.
○: 90% or more △: 80% or more and less than 90% ×: less than 80%

Heat shock resistance test:
A heat treatment in which a cylindrical shaped stainless steel with a diameter of 36 mm and a height of 25 mm is insert-molded with a uniform thickness of 2 mm resin thickness, treated for 1 hour in an atmosphere of -40 ° C and then for 1 hour in an atmosphere of 150 ° C. The shock test was repeated, and the cycle until a crack by visual judgment occurred was measured.
○: More than 500 times without cracks Δ: Cracks occurred between 100 and 500 times ×: Cracks occurred less than 100 times

Cooling time evaluation:
The cooling time evaluation was defined as the minimum cooling time when the gate part (1 mm × 3 mm, thickness: 1.0 mm) of the molded product was not broken during extrusion by the injection molding.
○: Less than 2 seconds Δ: 2 seconds or more and less than 4 seconds ×: 4 seconds or more

Release property evaluation:
The pellets were molded using an injection molding machine. An electric injection molding machine EC-100N (manufactured by Toshiba Molding Machinery) was used as the injection molding machine. The molding temperature at this time was 250 to 260 ° C. from the bottom of the hopper to the nozzle tip, and the mold temperature was 80 ° C.
In the evaluation of releasability, a molded product having an outer diameter of 40 mm, an inner diameter of 34 mm, and a height of 50 mm was injection-molded and evaluated from the resistance value at the time of extrusion.
○: Less than 5 kgf Δ: 5 kgf or more and less than 10 kgf ×: 10 kgf or more

Molded product appearance:
The molded article obtained by the injection molding was evaluated according to the following criteria.
○: No glass fiber floating △: Some glass fiber floating ×: Glass fiber floating

Bleed rating:
The molded product obtained by the injection molding was allowed to stand at 80 ° C. for 300 hours, and then evaluated according to the following criteria.
○: No bleed △: Partial bleed ×: With bleed

Examples 2-10, Comparative Examples 1-12
Using the raw materials described in Tables 1 and 2, a resin composition was obtained in the same manner as in Example 1, and its performance was evaluated. The results are listed in Tables 1 and 2.

As shown in Tables 1 and 2, according to the present invention, it is possible to provide an inorganic reinforced polyester resin composition that does not require a high injection pressure and a large molding machine associated therewith, and further has long-term durability and hydrolysis resistance. It becomes possible. Furthermore, in addition to these characteristics, it is possible to improve productivity by excellent mold release from the mold and shortening the cooling time. As a result, a material that sufficiently satisfies various performances such as mechanical properties, high-temperature durability, high-temperature and high-humidity resistance, heat shock resistance, and productivity, as an inorganic reinforced polyester resin composition having a complicated shape and thin wall, It can be provided.
Moreover, using a preferable thing as a composition, the weight ratio of (1) polyester, (2) unmodified polyolefin, (3) inorganic particulate filler, (4) inorganic reinforcing fiber, and (5) reactive compound is (By satisfying (1) / (2) / (3) / (4) / (5) = 100 / 5-15 / 0.3-3 / 1 to 50 / 0.5-3, the above characteristics are Further improvement will be at a level where high fluidity, high long-term stability, and productivity can be improved.
On the other hand, the resin composition outside the present invention does not have a satisfactory level of high fluidity, long-term durability, and hydrolysis resistance by injection molding.

  The resin composition of the present invention exhibits excellent fluidity and long-term stability as compared with conventional polyester resins, and has excellent mold release properties, and has mechanical properties, high temperature durability, high temperature resistance, high humidity resistance, and resistance. It is useful as a resin composition having various performances such as heat shock and productivity improvement.

Claims (6)

  (1) Polyester, (2) Unmodified polyolefin, (3) Inorganic particulate filler, (4) Inorganic reinforcing fiber, and (5) Polycarbodiimide as a reactive compound in a mass ratio of (1) / (2) / (3) / (4) / (5) = 100 / 5-15 / 0.3-3 / 1-50 / 0.5-3. (1) Polyester has a reduced viscosity of 0.40 dl / An inorganic reinforced polyester resin composition, wherein the composition is polybutylene terephthalate having a viscosity of g to 0.65 dl / g. (2) The unmodified polyolefin is polyethylene or a nonpolar ethylene copolymer, the density is 0.95 g / cm ³ or less, and (2) the melt flow rate at 190 ° C. and 2160 g of the polyolefin is 60 (g / 10 minutes) or more, The inorganic reinforced polyester resin composition according to claim 1.   The inorganic reinforcing polyester resin composition according to claim 1 or 2, wherein the (3) inorganic particulate filler is talc having an average particle size of 5 µm or less.   The inorganic reinforcing polyester resin composition according to any one of claims 1 to 3, wherein the (4) inorganic reinforcing fiber is a glass fiber.   5. The inorganic reinforced polyester resin composition according to claim 1, wherein the polycarbodiimide has a number average molecular weight of 500 to 10,000 and a carbodiimide group amount of 100 to 10,000 equivalent / ton. object.   A molded article obtained from the inorganic reinforced polyester resin composition according to any one of claims 1 to 5.