JP2017066260A - Polyester resin composition for cushioning material between members and molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cushioning material between members having thin wall moldability and excellent in heat resistance, flexibility and creep resistance.SOLUTION: There is provided a polyester resin composition for a cushioning material between members containing 100 pts.wt. of (A) a polybutylene terephthalate copolymer by condensation polymerizing dicarboxylic acid or an ester forming derivative thereof and diol or an ester forming derivative thereof and containing an aliphatic dicarboxylic acid unit having 6 to 20 carbon atoms of 3 to 20 mol% in all dicarboxylic acid or the ester forming derivative thereof and 0.2 to 2.0 pts.wt. of (B) a mold release agent.SELECTED DRAWING: None

Description

  The present invention relates to a polyester resin composition for cushioning material between members that retains heat resistance and flexibility.

  Polybutylene terephthalate resin (hereinafter sometimes abbreviated as PBT resin) is excellent in heat resistance, chemical resistance, electrical properties, dimensional stability, etc., so it can be used in various electrical and electronic equipment members, automobiles, trains, etc. It is widely used as a member for vehicles such as trains and other general industrial products.

  The inter-member cushioning material is mainly used to prevent problems caused by interference between members constituting the part, and is intended to provide airtightness when the members are joined (for example, packing or gasket) or heat generation. It is used in various forms depending on the purpose such as the purpose of preventing heat conduction from the member (for example, a spacer). In recent years, electrical and electronic equipment components and automotive components such as automobiles, trains, and trains have become smaller and lighter, and the use of digital electronics has increased the functionality of products, resulting in complicated component shapes. In addition to the widespread use of interstitial cushioning materials, the required properties such as heat resistance, mechanical properties, and durability have become sophisticated.

  Conventionally, as a resin composition for inter-member cushioning materials, Patent Document 1 describes a thermoplastic elastomer resin composition for a substrate storage container gasket in which airtightness is improved by suppressing volatile gas. Patent Document 2 discloses a polypropylene-made material for securing a coolant passage as a buffer material between members for suppressing a temperature difference between battery cells of an assembled battery formed by arranging a plurality of chargeable / dischargeable cells. An electrically insulating spacer and a heat conducting member made of silicone rubber for heat diffusion are described.

JP 2011-132293 A (Claims) JP 2010-55908 A (Claims)

  By the way, although resinization of parts is progressing in each field for the purpose of weight reduction, characteristics required for the cushioning material between the members made of the resin composition are generated in the resin member to maintain the airtightness between the members and to constitute. Flexibility is required to absorb dimensional tolerances. In order to maintain airtightness and structure, it is necessary to have strength (tensile strength or compressive strength) against the load applied to the member and durability (creep resistance) for long-term use, enabling complex product shapes. Formability is required.

  The resin composition of Patent Document 1 is excellent in airtightness as a gasket because of its high flexibility due to the constituent polyether ester component, but has low strength and is not suitable as an inter-member cushioning material for the purpose of high functionality. It was.

  In Patent Document 2, the cooling effect of the battery and the dimensional variation of the battery are absorbed by using two different buffer materials as the buffer material between the batteries. However, even if these buffer materials are combined, There was a problem that the long-term durability (creep resistance) was inferior.

  The present invention has been made in view of such a problem, and a main object thereof is to provide an inter-member cushioning material having thin-wall formability and excellent in heat resistance, flexibility, and creep resistance.

  As a result of intensive studies, the present inventors have made heat resistance, flexibility, creep resistance, and thin-wall formability (fluidity and separation capable of injection-molding a thin-wall shape) as an inter-member cushioning material that solves this problem. The present inventors have found that a copolymerized polyester resin composition having moldability) is suitable, and has reached the present invention. A polyester resin composition according to the present invention is a polybutylene terephthalate copolymer obtained by polycondensation of (A) a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof, and is a total dicarboxylic acid or an ester-forming derivative thereof. Containing 0.2 to 2.0 parts by weight of (B) release agent for 100 parts by weight of polybutylene terephthalate copolymer containing 3 to 20 mol% of aliphatic dicarboxylic acid units having 6 to 20 carbon atoms in the component It is characterized by doing.

  Since the polyester resin composition of the present invention has an unknown attribute of having excellent creep resistance, it has an effect that it is suitable for a cushioning material between members. Specifically, since it has flexibility, it can absorb the dimensional variation of the member when it is interposed between the members as a cushioning material. Further, as described above, since the polyester resin composition of the present invention is excellent in creep resistance, even when a load is applied to the molded product for a long time in order to maintain airtightness and structure, creep deformation and load loss Is hard to get up.

  Furthermore, since it has fluidity that enables injection molding of a thin-walled molded product and is excellent in releasability when the molded product is molded, it is possible to obtain a molded product having a small part or a complicated part shape.

(A) Polybutylene terephthalate copolymer (A) Polybutylene terephthalate copolymer in the present invention means terephthalic acid (or an ester-forming derivative thereof), 1,4-butanediol (or an ester-forming derivative thereof), and fatty acid It contains dicarboxylic acid as a copolymerization component. This is because particularly excellent flexibility can be expressed by copolymerizing an aliphatic dicarboxylic acid unit with polybutylene terephthalate. The polybutylene terephthalate copolymer may be copolymerized with other dicarboxylic acid (or its ester-forming derivative) or other diol (or its ester-forming derivative) that can be copolymerized, as long as its properties are not impaired. good.

  In order to express sufficient flexibility, the aliphatic dicarboxylic acid has 6 to 20 carbon atoms, more preferably dodecadioic acid. When the number of carbon atoms is less than 6, flexibility does not develop, while when it exceeds 20, the mechanical strength is lowered, the melting point is significantly lowered, and the heat resistance is lowered.

  The copolymerization ratio of the aliphatic dicarboxylic acid is in the range of 3 to 20 mol% in the total dicarboxylic acid constituting the (A) polybutylene phthalate copolymer or its ester-forming derivative component. From the viewpoint of imparting flexibility and productivity Is more preferably in the range of 6 to 15 mol%. When the copolymerization component is less than 3 mol%, flexibility is not expressed. On the other hand, when it exceeds 20 mol%, the mechanical strength is lowered, the melting point is significantly lowered, and the heat resistance is lowered.

  Examples of the other dicarboxylic acids include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, and 4,4′-diphenyl ether dicarboxylic acid. C6-C20 aliphatic such as acid, aromatic dicarboxylic acid such as 5-tetrabutylphosphonium isophthalic acid, 5-sodium sulfoisophthalic acid, diphenic acid, oxalic acid, succinic acid, malonic acid, glutaric acid, dimer acid Aliphatic dicarboxylic acids excluding dicarboxylic acids, alicyclic dicarboxylic acids such as 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid, and ester-forming derivatives thereof.

  The other diols (or ester-forming derivatives thereof) include aliphatic diols having 2 to 20 carbon atoms, that is, ethylene glycol, propylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, deca Aromatic dioxy compounds, such as methylene glycol, cyclohexanedimethanol, cyclohexanediol, dimer diol, etc., or long chain glycols having a molecular weight of 200-100,000, ie, polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol, etc. , 4'-dihydroxybiphenyl, hydroquinone, t-butylhydroquinone, bisphenol A, bisphenol S, bisphenol F, bisphenol-C and these And ester forming derivatives.

(B) Mold Release Agent (B) The mold release agent in the present invention is not particularly limited, but plant waxes such as carnauba wax and rice wax, animal waxes such as beeswax and lanolin, and montan Mineral wax such as wax, petroleum wax such as paraffin wax, polyethylene wax, castor oil and its derivatives, fatty oils such as fatty acid and its derivatives, and higher fatty acid derivatives include lauric acid, myristic acid, palmitic acid , Esters of higher fatty acids such as stearic acid, montanic acid and monohydric or dihydric alcohols, and these higher fatty acid esters partially with metal oxides such as Ca (OH) ₂ , NaOH, Mg (OH) ₂ , Zn _(OH) 2, LiOH, partially saponified ester was saponified with Al _{(OH) 3,} Fully saponified products obtained from higher grade fatty acids and metal oxides or metal hydroxides, higher fatty acids, complex esters condensed with dicarboxylic acids such as adipic acid as a binder to esters of polyhydric alcohols, higher fatty acids and monoamines Or the mono or diamide obtained from a diamine is mentioned. As the release agent for improving the release property of the polybutylene terephthalate copolymer, a mineral wax such as montan wax is preferably used.

  In the present invention, the (B) release agent contained in the polyester resin composition is 0.2 to 2.0 parts by weight with respect to 100 parts by weight of the component (A) from the viewpoint of releasability at the time of molding. From the viewpoint of mold contamination at the time, it is more preferably 0.2 to 1.0 part by weight, and most preferably 0.2 to 0.6 part by weight. When the release agent is less than 0.2, the effect of improving the release property is not exhibited, and when it exceeds 2.0 parts by weight, the mold contamination during molding becomes remarkable and short shot (underfilling) and This is not preferable because it causes a decrease in work efficiency such as appearance failure and increased mold maintenance frequency.

(C) Thermoplastic Elastomer The polyester resin composition of the present invention may contain (C) a thermoplastic elastomer in order to impart flexibility to the resin composition. (C) Known thermoplastic elastomers can be used. Specifically, natural rubber, polyethylene such as low-density polyethylene and high-density polyethylene, polypropylene, impact-modified polystyrene, polybutadiene, and styrene / butadiene. Copolymer, ethylene / propylene copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl acetate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / maleic anhydride copolymer Polyester elastomer such as polymer, polybutylene terephthalate / poly (tetramethylene oxide) glycol block copolymer, polybutylene terephthalate / isophthalate / poly (tetramethylene oxide) glycol block copolymer, MBS Others include core-shell elastomer of the acrylic, it may be used alone or in combination. Among these, polybutylene terephthalate / poly (tetramethylene oxide) glycol block copolymer is preferable from the viewpoints of heat resistance and moldability.

  In the present invention, the content of the (C) thermoplastic elastomer is preferably in the range of 1 to 20 parts by weight with respect to 100 parts by weight of the component (A), and 1 to 10 parts by weight from the viewpoint of fluidity and mechanical strength. A range is more preferable. When it is in the range of 1 to 20 parts by weight, flexibility can be imparted while maintaining mechanical properties and moldability.

(D) Crystal nucleating agent The resin composition of the present invention may contain (D) a crystal nucleating agent. (D) The crystal nucleating agent may be either an inorganic crystal nucleating agent or an organic crystal nucleating agent. Examples of inorganic crystal nucleating agents include synthetic mica, talc, clay, zeolite, magnesium oxide, calcium sulfide, boron nitride, neodymium oxide, etc., modified with organic substances to increase dispersibility in the composition. It is preferable that As organic crystal nucleating agents, sodium benzoate, potassium benzoate, lithium benzoate, calcium benzoate, magnesium benzoate, barium benzoate, lithium terephthalate, sodium terephthalate, potassium terephthalate, sodium toluate, Organic carboxylic acid metal salts such as sodium salicylate, potassium salicylate, zinc salicylate, aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium β-naphthalate, sodium cyclohexanecarboxylate, sodium p-toluenesulfonate, sodium sulfoisophthalate, etc. Organic sulfonates, sorbitol compounds, metal salts of phenylphosphonate, sodium-2,2′-methylenebis (4,6-di-t-butylpheny ) And a phosphorus compound metal salts such as phosphate and the like. By blending these crystal nucleating agents, a thermoplastic resin composition and a molded product excellent in mechanical properties, moldability, heat resistance and durability can be obtained. As the crystal nucleating agent for improving the crystallization characteristics of the polybutylene terephthalate copolymer, talc is preferably used.

  In the present invention, the content of the (D) crystal nucleating agent is preferably in the range of 0.05 to 5 parts by weight with respect to 100 parts by weight of the component (A), and 0.05 in terms of moldability and flexibility. More preferably, it is in the range of ˜1 part by weight.

(E) Polyfunctional compound having three or more functional groups The resin composition of the present invention may contain (E) a polyfunctional compound having three or more functional groups. (E) The polyfunctional compound having three or more functional groups serves as a fluidity improver. The component (E) is not limited as long as it has three or more functional groups in the molecule, and may be a low molecular compound or a high molecular weight polymer. The functional group of component (E) is preferably at least one selected from a hydroxyl group, a carboxyl group, an amino group, a glycidyl group, an isocyanate group, an ester group, and an amide group, and at least one component (E). It is more preferable that it has the above hydroxyl group from a fluidity | liquidity point, and it is more preferable that (E) component has 3 or more hydroxyl groups.

  Among the components (E), compounds having three or more hydroxyl groups as functional groups include 1,2,4-butanetriol, 1,2,5-pentanetriol, 1,2,6-hexanetriol, , 2,3,6-hexanetetrol, glycerol, diglycerol, triglycerol, tetraglycerol, pentaglycerol, hexaglycerol, triethanolamine, trimethylolethane, trimethylolpropane, ditrimethylolpropane, trimethylolpropane, 2- Methylpropanetriol, 2-methyl-1,2,4-butanetriol, pentaerythritol, dipentaerythritol, tripentaerythritol, methylglucoside, sorbitol, mannitol, sucrose, 1,3,5-trihydroxybenzene, 1,2 , 4-to Polymers such as polyhydric alcohol or a polyvinyl alcohol having a carbon number of 3 to 24, such as hydroxy benzene. Of these, glycerin, diglycerin, trimethylolpropane, ditrimethylolpropane, pentaerythritol, and dipentaerythritol having a branched structure are preferable from the viewpoint of fluidity and mechanical properties.

  From the viewpoint of fluidity and mechanical properties, it is preferable that (E) the polyfunctional compound having 3 or more functional groups contains one or more alkylene oxide units. As preferred examples of the alkylene oxide unit, aliphatic alkylene oxide units having 1 to 4 carbon atoms are effective. Specific examples include a methylene oxide unit, an ethylene oxide unit, a trimethylene oxide unit, a propylene oxide unit, a tetramethylene oxide unit, 1,2-butylene oxide units, 2,3-butylene oxide units or isobutylene oxide units. In the present invention, it is particularly preferable to use a compound containing an ethylene oxide unit or a propylene oxide unit as an alkylene oxide unit.

  The number of alkylene oxide units contained in the polyfunctional compound having three or more functional groups (E) used in the present invention is preferably 0.1 to 20 alkylene oxide units per functional group. It is more preferably 5 to 10, and further preferably 1 to 5.

  In view of the fluidity of the polyester resin composition, (E) a polyfunctional compound having three or more functional groups containing one or more alkylene oxide units is particularly preferred as (poly) oxymethylene glycerin, (poly) Oxypropylene glycerin, (poly) oxyethylene diglycerin, (poly) oxyethylene trimethylolpropane, (poly) oxypropylene trimethylolpropane, (poly) oxyethylene ditrimethylolpropane, (poly) oxypropylene ditrimethylolpropane, (poly ) Oxyethylene pentaerythritol, (poly) oxypropylene pentaerythritol, (poly) oxyethylene dipentaerythritol, (poly) oxypropylene dipentaerythritol.

  In the present invention, (E) the blending amount of the polyfunctional compound having three or more functional groups is preferably in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of component (A). From the viewpoint of properties and mechanical properties, it is more preferable to mix in the range of 0.1 to 3 parts by weight, and most preferable to mix in the range of 0.1 to 1 part by weight.

(F) Alkylene oxide adduct of compound having bisphenol skeleton The resin composition of the present invention may contain (F) an alkylene oxide adduct of a compound having a bisphenol skeleton. (F) The alkylene oxide adduct of a compound having a bisphenol skeleton functions as a fluidity improver. The component (F) is a structure in which an alkylene oxide unit is added to a compound having a bisphenol skeleton in the molecule, and is not particularly limited as long as at least one of the terminal structures having a functional group is a hydroxyl group. It is most preferable that all of the terminal structures having a functional group are hydroxyl groups from the viewpoint of excellent hydrolysis characteristics.

  In the present invention, the alkylene oxide unit of the component (F) is preferably ethylene oxide, propylene oxide or the like, and more preferably ethylene oxide from the viewpoint of fluidity, from the viewpoint of excellent mechanical properties and fluidity.

  (F) Preferred examples of the alkylene oxide adduct of a compound having a bisphenol skeleton include 2,2-bis (4-polyoxyethylene-oxyphenyl) propane and 2,2-bis (4-polyoxypropylene-oxyphenyl). Examples include alkylene oxide adducts having 2 to 20 repeating units of alkylene oxide units such as propane and 2,2-bis (4-polyoxybutylene-oxyphenyl) propane. Among these, 2,2-bis (4- (4)) has an alkylene oxide unit of ethylene oxide and the number of repeating units of ethylene oxide unit of 2 from the viewpoints of fluidity, handling at the time of melt kneading, hydrolysis resistance, and mechanical properties. Polyoxyethylene-oxyphenyl) propane is most preferred.

  In the present invention, the compounding amount of the alkylene oxide adduct of the compound (F) having a bisphenol skeleton is in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the component (A), and from the viewpoint of mechanical properties, It is preferable to mix | blend in the range of 0.1-2 weight part, and it is more preferable to mix | blend in the range of 0.2-1 weight part.

  One or more antioxidants, stabilizers, ultraviolet absorbers, antibacterial agents, colorants including pigments and dyes, antistatic agents, and the like are added to the polyester resin composition of the present invention within a range that does not impair the purpose of the present invention. can do.

  Examples of antioxidants include 2,6-di-t-butyl-4-methylphenol, tetrakis (methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) methane, tris Phenol compounds such as (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, sulfur such as dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate And phosphorous compounds such as trisnonylphenyl phosphite and distearyl pentaerythritol diphosphite.

  Stabilizers include benzotriazole compounds including 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, and benzophenone compounds such as 2,4-dihydroxybenzophenone, mono- or distearyl phosphate, trimethyl phosphate And phosphoric acid esters.

  These various additives may have a synergistic effect by combining two or more kinds, and may be used in combination.

  For example, the additive exemplified as the antioxidant may act as a stabilizer or an ultraviolet absorber. Some of those exemplified as stabilizers also have an antioxidant action and an ultraviolet absorption action. In other words, the classification is for convenience and does not limit the action.

  The method for producing the polyester resin composition of the present invention is not particularly limited as long as the requirements specified in the present invention are satisfied. For example, (A) a polybutylene terephthalate copolymer, (B) a release agent, and necessary Depending on the above, other components are preferably used at a melting point of the component (A), a method of uniformly melting and kneading with a single or twin screw extruder, a method of removing the solvent after mixing in the solution, and the like. From the viewpoint of productivity, a method of uniformly melting and kneading with a single-screw or twin-screw extruder is preferable, and with a twin-screw extruder, uniformly melting and kneading in that a resin composition excellent in fluidity and mechanical properties can be obtained. The method is more preferred.

  In the present invention, when melt-kneading, for example, a method of charging each component is performed by using an extruder having two charging ports, and (A) a polybutylene terephthalate copolymer from a main charging port installed on the screw base side. (B) A method of supplying a release agent and other components as required, or (A) a polybutylene terephthalate copolymer supplied from the main inlet, and a sub-installed between the main inlet and the tip of the extruder. Examples thereof include a method in which (B) a release agent is supplied from an inlet and melt mixed.

  The molded article comprising the polyester resin composition thus obtained is generally molded by a known thermoplastic resin molding method such as injection molding, extrusion molding, blow molding, transfer molding, vacuum molding, etc., among which injection molding is preferable.

  The polyester resin composition for inter-component cushioning material of the present invention makes use of its excellent properties to buffer various general industrial products such as automobile parts, electrical / electronic parts, building members, various containers, daily necessities, household goods and sanitary goods. It can utilize for member use. Among them, it is useful as a packing for connectors such as a wire harness connector, a gasket for a lithium ion battery, and an assembled battery spacer from the viewpoint of thin-wall formability, flexibility, and creep resistance.

  Hereinafter, the present invention will be described in more detail with reference to examples. The abbreviations and contents of the raw materials used in Examples and Comparative Examples are shown below.

(A) Component Polybutylene terephthalate copolymer A-1: Polybutylene terephthalate / dodecanedioic acid copolymer (mol ratio in total dicarboxylic acid or its ester-forming derivative component: terephthalic acid / dodecanedioic acid = 87/13)
A-2: Polybutylene terephthalate / octadecanedioic acid copolymer (mol ratio in total dicarboxylic acid or its ester-forming derivative component: terephthalic acid / octadecanedioic acid = 90/10)
A-3: Polybutylene terephthalate / tetracosanedioic acid copolymer (mol ratio in the total dicarboxylic acid or its ester-forming derivative component: terephthalic acid / tetracosanedioic acid = 90/10)
Resins A′-4 other than polybutylene terephthalate copolymer: Polyetherester block copolymer (MFR: 23 g / 10 min (220 ° C., 2160 g))
A′-5: Polybutylene terephthalate (MFR: 32 g / 10 min (250 ° C., 1000 g))
A′-6: Polypropylene (MFR: 5.6 g / 10 min (190 ° C., 2160 g)

(B) Release agent B-1: Montanic acid ester (“Licowax OP” (trade name) manufactured by Clariant Japan Co., Ltd.)
B-2: Ethylene bis-stearic acid amide ("PALMOWAX SF" (trade name) manufactured by Oreo Chemical Co., Ltd.)

(C) Thermoplastic elastomer C-1: Polybutylene terephthalate / poly (tetramethylene oxide) glycol block copolymer (MFR: 43 g / 10 min (230 ° C., 2160 g))
C-2: ethylene / methyl acrylate / glycidyl methacrylate copolymer (MFR: 6.0 g / 10 min (190 ° C., 2160 g))
C-3: ethylene / ethyl acrylate / maleic anhydride copolymer (MFR: 7.0 g / 10 min (190 ° C., 2160 g))

(D) Crystal nucleating agent D-1: Hydrous magnesium silicate (talc) (Hightron (trade name) manufactured by Takehara Chemical Co., Ltd.)

(E) Polyfunctional compound E-1 having three or more functional groups: Polyoxypropylene trimethylolpropane ether (TMP-F32 (trade name) manufactured by Nippon Emulsifier Co., Ltd.)

(F) Alkylene oxide adduct of compound having bisphenol skeleton F-1: 2,2-bis (4-polyoxyethylene-oxyphenyl) propane (BA-2S (trade name) manufactured by Nippon Emulsifier Co., Ltd.)

  Below, the evaluation method in an Example and a comparative example is shown collectively.

(1) Tensile properties A dumbbell test piece was molded at a cylinder temperature of 240 to 270 ° C. and a mold temperature of 80 ° C. using the resin compositions obtained in the examples and comparative examples, and conformed to ISO527-1,2. The tensile strength and tensile elongation were measured. When polypropylene was used, a dumbbell test piece was molded at a cylinder temperature of 200 to 210 ° C. and a mold temperature of 50 ° C., and measured by the same measurement method.

  If the tensile strength is 25 MPa or more, it can be determined that the strength of the inter-member cushioning resin composition is good. A tensile strength of 25 MPa or more was judged as ◯, and a tensile strength of less than 25 MPa was judged as x.

(2) Flexural modulus Using the resin compositions obtained in the examples and comparative examples, a dumbbell test piece was molded at a cylinder temperature of 240 to 270 ° C. and a mold temperature of 80 ° C., and in accordance with ISO 178, flexural elasticity The rate was measured. When polypropylene was used, it was molded at a cylinder temperature of 200 to 210 ° C. and a mold temperature of 50 ° C. and measured by the same measurement method.

  If the flexural modulus is less than 1000 MPa, it can be determined that the flexibility of the inter-member cushioning resin composition is good. Bending elastic modulus was determined to be less than 1000 MPa, and 1000 MPa or more was determined to be x.

(3) Creep resistance (compressive stress relaxation property)
Using the resin compositions obtained in each Example and Comparative Example, a dumbbell test piece was molded at a cylinder temperature of 240 to 270 ° C. and a mold temperature of 80 ° C., and a width of 10 mm at the center of the parallel part of the dumbbell test piece was high. After cutting to a thickness of 10 mm and a thickness of 4.0 mm, a compression test was started at an initial stress of 10.0 MPa in the flow direction of the dumbbells using a cutting test piece, and the stress after compression for 100 hr was measured. The stress reduction rate was obtained and the compression stress relaxation characteristics were evaluated. When polypropylene was used, molding was performed at a cylinder temperature of 200 to 210 ° C. and a mold temperature of 50 ° C., and measurement was performed by the same measurement method.
Compressive stress reduction rate (%) = 100−compressive stress (after 100 hr compression) (MPa) × 100 / compressive stress (initial stress) (MPa)

  If the compression stress reduction rate is less than 30%, it can be judged that the creep resistance is good. The compression stress reduction rate of less than 30% was judged as ◯, and 30% or more was judged as ×.

(4) Release force Using the resin compositions obtained in the examples and comparative examples, the cylinder temperature is 240 to 270 ° C., the mold temperature is 80 ° C., the width is 30 mm, the height is 30 mm, the depth is 30 mm, and the thickness is 1.5 mm. The box-shaped molded product was molded from the side pin gate, and the resistance when the bottom of the small box was projected with the ejector pin was measured as the mold release force. When polypropylene was used, molding was performed at a cylinder temperature of 200 to 210 ° C. and a mold temperature of 50 ° C., and measurement was performed by the same measurement method.

  If the mold release force is less than 200 N, it can be judged that the mold release property is good when the molded product made of the resin composition of the present invention is molded. The release force of less than 200N was judged as ◯, and 200N or more was judged as ×.

(5) Fluidity Using a strip-shaped molded product having a thickness of 0.5 mmt and a width of 10 mm, the flowability was judged. The above-mentioned strip-shaped molding, in which the resin compositions of Examples and Comparative Examples were injection molded at a cylinder temperature of 240 to 270 ° C., a mold temperature of 80 ° C., an injection pressure of 50 MPa, an injection time of 10 seconds, and a cooling time of 10 seconds. The product length was defined as the flow length. When polypropylene was used, molding was performed at a cylinder temperature of 200 to 210 ° C. and a mold temperature of 50 ° C., and measurement was performed by the same measurement method.

  If a flow length is 70 mm or more, it can be judged that it is favorable as fluidity | liquidity at the time of shape | molding a molded article from the resin composition of this invention. A flow length of 70 mm or more was judged as ◯, and a flow length less than 70 mm was judged as ×.

(6) Appearance of molded product Using the resin compositions obtained in the examples and comparative examples, the cylinder temperature is 240 to 270 ° C., the mold temperature is 80 ° C., the width is 30 mm, the height is 30 mm, the depth is 30 mm, and the thickness is 1.5 mm. The box-shaped molded product was molded from the side pin gate, and the appearance of the flow end portion of the molded product was visually confirmed. When polypropylene was used, molding was performed at a cylinder temperature of 200 to 210 ° C. and a mold temperature of 50 ° C., and measurement was performed by the same measurement method.

  When surface roughness due to improper transfer or burning due to adiabatic compression is seen in the flow end part of the above box-shaped molded product, it is a poor appearance due to a large amount of gas components generated by molding, that is, when used as a cushioning material such as a gasket It can be determined that the airtightness is impaired. The case where surface roughness or burning was not observed at the flow end of the molded product by visual observation was judged as ◯, and the case where surface roughness or burning was confirmed was judged as x.

[Examples 1 to 10, Comparative Examples 1 to 8]
According to the composition shown in Table 1 and Table 2, melt kneading was performed using a twin screw extruder (ZSK57 manufactured by WERNER & Pfeiderer) having a screw diameter of 57 mmφ set at a cylinder temperature of 250 ° C. The strand discharged from the die was cooled in a cooling bath and then pelletized with a strand cutter to obtain a resin composition. The results of evaluating the obtained resin composition by the above method are shown in Tables 1 and 2.

  From the results in Tables 1 and 2, the following is clear.

  From comparison between Examples 1 to 10 and Comparative Examples 1 to 4, (A) Polyester resin containing 0.2 to 2.0 parts by weight of release agent with respect to 100 parts by weight of polybutylene terephthalate copolymer. It can be seen that the composition is excellent in mechanical strength and releasability. When the amount of the (B) release agent is more than 2.0 parts by weight as in Comparative Example 3, the appearance of the molded product is deteriorated.

  From comparison between Examples 1 and 2 using a polybutylene terephthalate copolymer as a main component as a resin component and Comparative Example 6 using a polybutylene terephthalate as a main component, (A) 100 parts by weight of a polybutylene terephthalate copolymer On the other hand, it can be seen that the polybutylene terephthalate resin composition containing 0.2 to 2.0 parts by weight of the release agent (B) is excellent in strength. Further, from comparison between Examples 1 and 2 using a polybutylene terephthalate copolymer as a main component and Comparative Examples 6 to 7 using a polybutylene terephthalate as a main component, (A) 100 weight of a polybutylene terephthalate copolymer It can be seen that the polybutylene terephthalate resin composition containing 0.2 to 2.0 parts by weight of the (B) release agent with respect to parts is excellent in flexibility and fluidity. Further, from comparison between Examples 1 and 2 using polybutylene terephthalate copolymer as a main component and Comparative Example 8 using polypropylene as a main component, (A) 100 parts by weight of polybutylene terephthalate copolymer (B It can be seen that the polybutylene terephthalate resin composition containing 0.2 to 2.0 parts by weight of the release agent is excellent in flexibility and stress relaxation characteristics.

Claims (9)

(A) A polybutylene terephthalate copolymer obtained by polycondensation of a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof, and a fatty acid having 6 to 20 carbon atoms in the total dicarboxylic acid or an ester-forming derivative component thereof An inter-member cushioning material containing 0.2 to 2.0 parts by weight of a release agent (B) with respect to 100 parts by weight of a polybutylene terephthalate copolymer containing 3 to 20 mol% of an aromatic dicarboxylic acid unit Polyester resin composition. The polyester resin composition for inter-member cushioning materials according to claim 1, wherein the fatty acid dicarboxylic acid unit of the (A) polybutylene terephthalate copolymer is dodecadioic acid. The polyester resin for inter-member cushioning materials according to claim 1 or 2, further comprising (C) 1 to 20 parts by weight of a thermoplastic elastomer as a resin component with respect to 100 parts by weight of the (A) polybutylene terephthalate copolymer. Composition. The inter-member cushioning polyester according to any one of claims 1 to 3, further comprising (D) 0.05 to 5 parts by weight of a crystal nucleating agent with respect to 100 parts by weight of the (A) polybutylene terephthalate copolymer. Resin composition. 5. The composition according to claim 1, wherein (E) 0.01 to 5 parts by weight of a polyfunctional compound having three or more functional groups is further blended with 100 parts by weight of the (A) polybutylene terephthalate copolymer. The polyester resin composition for cushioning materials between members in any one. The polyester resin composition for inter-member cushioning materials according to claim 5, wherein the polyfunctional compound (E) having three or more functional groups contains one or more alkylene oxide units. (E) The functional group of the polyfunctional compound having three or more functional groups is at least one group selected from a hydroxyl group, a carboxyl group, an amino group, a glycidyl group, an isocyanate group, an ester group, and an amide group. The polyester resin composition for cushioning materials between members according to claim 5 or 6. 0.1 to 5 weight percent of a compound having (F) an alkylene oxide adduct of a compound having a bisphenol skeleton, wherein at least one of the terminal structures has a hydroxyl group, relative to 100 weight parts of the (A) polybutylene terephthalate copolymer. The polyester resin composition for cushioning materials between members according to any one of claims 1 to 4, wherein the polyester resin composition is partly blended. The molded object which consists of a polyester resin composition in any one of Claims 1-8.