JP2007284561A - Resin composition and resin molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin molded product excellent in shock-absorbing capacity, antistaticity, flame retardancy, impact strength and releasability, and to provide a resin composition suitable for the resin molded product. <P>SOLUTION: The resin composition comprises 25-86 mass% of (A) a polyester elastomer, 2-63 mass% of (B) polybutylene terephthalate, 7-30 mass% of (C) carbon fiber, and 5-66 mass% of (D) a halogen-based flame retardant containing a halogenated bisphenol A-type epoxy resin(d1). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resin composition and a resin molded article excellent in flame retardancy and conductivity used for electric / electronic parts.

  In recent years, the performance of electrical and electronic equipment represented by computers and the like has been particularly remarkable, and the integration has been progressing at a much faster rate than before. Recently, along with the increase in the density and capacity of hard disks used as storage media for computers and the like, small hard disk drives (small HDDs) having a disk capacity of about 100 yen and a storage capacity of several gigabytes have been commercialized. I'm going to. Conventionally, the use of a hard disk has been mainly used as a storage medium of a personal computer. However, it has been used for portable music appreciation equipment due to downsizing.

  With the spread of such applications, the environment in which hard disks are used has changed, and in order to respond to this, resin bumpers have been attached to small HDDs. This resin bumper is installed to protect internal mechanism parts from impacts such as dropping, and to prevent destruction of internal electric circuits from static electricity generated from clothing, etc., and is used for resin bumpers The material must have shock absorption and conductivity. In addition, the resin bumper is also required to have flame retardancy generally required for electric and electronic parts.

As the resin material used for the resin bumper, an elastomer resin such as a polyester elastomer is effective in terms of impact absorption, but the polyester elastomer has low flame retardancy. In general, a flame retardant is used to impart flame retardancy to a resin (see, for example, Patent Document 1).
Patent Document 1 describes a polyester resin composition in which a specific halogenated bisphenol A type epoxy resin is added as a flame retardant to a polyester resin. However, when a flame retardant as described herein is applied to a polyester elastomer, the crystallinity of the resin composition is reduced, and solidification does not proceed during molding, making it difficult to release from the mold. A malfunction occurs.
As described above, the conventional techniques have not yet satisfied all of the impact absorption property, antistatic property, flame retardancy and releasability.
JP 2003-26904 A

  An object of the present invention is to provide a resin molded article having good impact absorbability, antistatic properties, flame retardancy, impact strength, and releasability, and a resin composition suitable for this resin molded article.

The present invention comprises 25 to 86% by mass of a polyester elastomer (A), 2 to 63% by mass of a polybutylene terephthalate (B), 7 to 30% by mass of a carbon fiber (C), and a halogenated bisphenol A type epoxy resin (d1). The present invention relates to a resin composition containing 5 to 66% by mass of a halogen-containing flame retardant (D), a flexural modulus of 3000 to 7500 MPa or less, a Charpy strength of 60 kJ / m ² or more, and a surface resistance value of 1000Ω. Hereinafter, the flame-retardant property relates to a resin molded product having a thickness of 0.8 mm and V-1 or more.

The resin molded product of the present invention has a good impact absorbability because the flexural modulus is in a specific range, and has a good antistatic property because the surface resistance value is not more than a specific value. Good flame retardancy. Therefore, it can be suitably used for electrical and electronic applications that require these characteristics, and is particularly suitable for resin for resin bumpers of small HDDs.
Moreover, the resin composition of the present invention is suitable for obtaining the above-mentioned resin molded product, and is excellent in moldability (mold release property).

  The resin composition of the present invention comprises 25 to 86% by mass of polyester elastomer (A), 2 to 63% by mass of polybutylene terephthalate (B), 7 to 30% by mass of carbon fiber (C), and halogenated bisphenol A type epoxy resin. It contains 5 to 66% by mass of a halogenated flame retardant (D) containing (d1).

Although it does not restrict | limit especially as a polyester elastomer (A), For example, a polyester-polyether block copolymer, a polyester-polyester block copolymer, etc. are mentioned. Among these, a polyester-polyether block copolymer is preferable from the viewpoint of impact absorption.
The polyester-polyether block copolymer is a block copolymer having a polyester segment composed of an alkylene terephthalate unit as a hard segment and a poly (alkylene oxide) glycol segment composed of an alkylene oxide unit as a soft segment.

The polyester segment constituting the hard segment is a polymer segment having terephthalic acid as the main acid component and aliphatic glycol having 2 to 10 carbon atoms as the main diol component, or 20 mol of dicarboxylic acid or glycol other than the above in any combination. % Is a polymer segment copolymerized in the range of not more than%.
Although it does not restrict | limit especially as a poly (alkylene oxide) glycol segment which comprises a soft segment, For example, it is single, such as a poly (ethylene oxide) glycol segment, a poly (propylene oxide) glycol segment, a poly (tetramethylene oxide) glycol segment Segments of polyglycols, segments of random or block copolymerized polyglycols of ethylene oxide and propylene oxide, segments of polyglycols copolymerized with other copolymerization components in the range of 20 mol% or less Is mentioned. These soft segments can be used alone or in combination of two or more soft segments.

  Specific examples of the polyester-polyether block copolymer include, for example, a polytetramethylene terephthalate-polytetramethylene oxide block copolymer, a polytetramethylene terephthalate-polyethylene oxide block copolymer, and a polyethylene terephthalate-polytetramethylene oxide block. Examples thereof include a copolymer and a polyethylene terephthalate-polyethylene oxide block copolymer. Of these, polytetramethylene terephthalate-polytetramethylene oxide block copolymers are preferable from the viewpoint of impact absorption.

Content of a polyester elastomer (A) is 25-86 mass% in the resin composition whole quantity.
When the content of the component (A) is 25% by mass or more, the impact absorbability tends to be good, and when the content of the component (A) is 86% by mass or less, sufficient flame retardancy There is a tendency to gain.
(A) As for the lower limit of content of a component, 27 mass% or more is more preferable, and 30 mass% or more is especially preferable. Further, the upper limit value of the content of the component (A) is more preferably 60% by mass or less, and particularly preferably 55% by mass or less.
The production method of the polyester elastomer (A) is not particularly limited, and can be produced by a commonly used direct esterification method or transesterification esterification reaction, followed by a polycondensation reaction, and further by solid phase polymerization. It is also possible to increase the molecular weight.

The polybutylene terephthalate (B) used in the present invention is obtained by a known polycondensation reaction of a dicarboxylic acid mainly composed of terephthalic acid or an ester-forming derivative thereof and a glycol component mainly composed of 1,4-butanediol. Polymer.
Specifically, terephthalic acid or an ester-forming derivative thereof (for example, dimethyl terephthalate) is the main component, and is combined with isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4 '-Diphenoxyethanedicarboxylic acid, p-oxybenzoic acid, sebacic acid, adipic acid, dimer acid, etc. in combination with dicarboxylic acid component and 1,4-butanediol as main components, ethylene glycol or ethylene oxide , And a glycol component obtained by appropriately combining glycols such as trimethylene glycol, hexamethylene glycol, decamethylene glycol, and cyclohexanedimethanol as appropriate.

  The intrinsic viscosity ([η]) of the polybutylene terephthalate (B) is not particularly limited, but the intrinsic viscosity measured with an equal mass mixture of 1,1,2,2-tetrachloroethane and phenol in an atmosphere at 25 ° C. Is preferably 0.5 to 2 dl / g. When the intrinsic viscosity is 0.5 dl / g or more, a molded product having a sufficient strength tends to be obtained. When the intrinsic viscosity is 2 dl / g or less, the fluidity tends to be good and the filling property tends to be sufficient. The lower limit of the intrinsic viscosity is more preferably 0.7 dl / g or more, and particularly preferably 0.8 dl / g or more. The upper limit is more preferably 1.7 dl / g or less, and particularly preferably 1.5 dl / g or less.

Content of polybutylene terephthalate (B) is 2-63 mass% in the resin composition whole quantity.
When the content of the component (B) is 2% by mass or more, solidification by crystallization at the time of molding tends to be sufficient and the releasability tends to be good, and the content of the component (B) is 63% by mass. In the following cases, sufficient impact absorbability tends to be obtained.
(B) As for the lower limit of content of a component, 3 mass% or more is more preferable, and 4 mass% or more is especially preferable. Moreover, the upper limit of the content of the component (B) is more preferably 40% by mass or less, and particularly preferably 30% by mass or less.

The carbon fiber (C) used in the present invention is a component that imparts conductivity.
The carbon fiber (C) is not particularly limited, and examples thereof include PAN-based, pitch-based, or vapor-grown carbon fibers, such as long fiber type and short fiber type chopped strands, milled fibers, and the like. It is done. In order to suppress fiber breakage during molding or the like, a high-strength / high-stretch type is preferable, and a PAN-based carbon fiber capable of obtaining these characteristics is preferable.

The elastic modulus of the carbon fiber (C) is not particularly limited, but is preferably 195 to 450 GPa from the viewpoint of suppressing fiber breakage during molding. The lower limit value of the elastic modulus of the carbon fiber (C) is more preferably 215 GPa or more, and the upper limit value is more preferably 390 GPa or less.
Moreover, about the diameter of carbon fiber (C), although it does not restrict | limit in particular, it is preferable that it is 3-10 micrometers. The lower limit value of the diameter of the carbon fiber (C) is more preferably 5 μm or more, and the upper limit value is more preferably 8 μm or less.

  The surface treatment of the carbon fiber (C) is not particularly limited, but it is preferable to perform a treatment such as a surface oxidation treatment. In the present invention, the carbon fiber (C) is used as a conductive filler in order to set the surface resistance value of the resin molded product to a predetermined value. However, if the carbon fiber (C) is excessively blended, the elastic modulus increases and shock absorption is increased. It will be disadvantageous. For this reason, it is preferable to add a small amount of carbon fiber (C) to reach a predetermined surface resistance value.

Examples of the oxidation treatment method include surface oxidation by energization treatment, and oxidation treatment in an oxidizing gas atmosphere such as ozone, and energization treatment is preferably used.
Further, epoxy type, polyamide type, urethane type, polyester type and the like can be mentioned as sizing agents. It is preferable to use epoxy type as primary sizing agent, and use polyamide type or urethane type sizing agent as secondary sizing agent. More preferably, the system is used.

The form of the carbon fiber (C) is not particularly limited, but is used in the form of a strand made of a bundle of thousands to hundreds of thousands of carbon fibers or a pulverized milled form. Also for the strand form, it is possible to use a roving method for direct introduction or a chopped strand cut to a predetermined length.
Moreover, you may use the carbon fiber which coat | covered the surface with the metal as carbon fiber (C). Preferred as the metal-coated carbon fiber is nickel-coated carbon fiber.

Content of carbon fiber (C) is 7-30 mass% in the resin composition whole quantity. When the content of the component (C) is 7% by mass or more, sufficient conductivity tends to be obtained, and when the content of the component (C) is 30% by mass or less, sufficient shock absorption is achieved. There is a tendency to gain.
(C) As for the lower limit of content of a component, 10 mass% or more is preferable. Moreover, the upper limit of the content of the component (C) is preferably 25% by mass or less.

The halogen flame retardant (D) used in the present invention contains a halogenated bisphenol A type epoxy resin (d1).
The halogenated bisphenol A type epoxy resin (d1) may be either a case where the terminal epoxy group is blocked or a case where it is not blocked.
When the terminal epoxy group is blocked, the compound is not particularly limited, and examples thereof include monofunctional alcohols such as t-butanol, aliphatic carboxylic acids such as acetic acid, and aromatic carboxylic acids such as benzoic acid. Functional active hydrogen-containing compounds can be used.

Specifically, in terms of reactivity and stability, phenols such as phenol, naphthol, alkylphenol (C1-10 alkylphenol such as cresol and tertiary butylphenol), and halogenated phenol (tribromophenol, trichlorophenol, etc.) are used. It is preferable to use it.
Particularly preferable blocking agents include mono- to penta-halogenated phenols such as dibromophenol, tribromophenol, tetrabromophenol, trichlorophenol (particularly bromophenols) in order to increase the halogen content of the halogenated bisphenol A type epoxy resin. ).

The production method of the component (d1) is not particularly limited. For example, (1) a halogenated bisphenol and epichlorohydrin are reacted to produce a halogenated bisphenol A type epoxy resin, and this epoxy resin is used as a single blocker. And (2) reacting a halogenated bisphenol with epichlorohydrin to produce a halogenated bisphenol A diglycidyl ether, the epoxy resin and the halogenated bisphenol and It may be produced by reacting the monofunctional active hydrogen-containing compound. (3) Halogenated bisphenol and epichlorohydrin are reacted to form a halogenated bisphenol A diglycidyl ether, which is then halogenated with this epoxy resin. Bisf In the case where a halogenated bisphenol A type epoxy resin is produced by reacting with diol A and the terminal epoxy group is blocked, the epoxy resin may be produced by reacting with the monofunctional active hydrogen-containing compound. .
In addition, in each method of said (1)-(3), the value of the blockage rate in a halogenated bisphenol A type epoxy resin, a number average molecular weight, and the average degree of polymerization n is adjusted by adjusting the use rate of each raw material component. Can be adjusted.

The number average molecular weight of the halogenated bisphenol A type epoxy resin (d1) is not particularly limited, but is preferably 500 to 100,000.
In particular, when only the component (d1) is used as the halogen flame retardant (D), the number average molecular weight of the component (d1) is preferably 15000 or more. When the number average molecular weight of the halogenated bisphenol A type epoxy resin (d1) is 15000 or more, solidification by crystallization during molding tends to be sufficient, and the releasability tends to be good. The lower limit of the number average molecular weight of the component (d1) is preferably 18000 or more, particularly preferably 20000 or more. Further, the upper limit value of the number average molecular weight of the component (d1) is particularly preferably 70000 or less.

  In addition to the halogenated bisphenol A type epoxy resin (d1), the halogen flame retardant (D) can contain a halogenated polyacrylate resin (d2) as necessary. In particular, when the number average molecular weight of the halogenated bisphenol A type epoxy resin (d1) is less than 15,000, it is preferable to use the halogenated bisphenol A type epoxy resin (d1) and the halogenated polyacrylate resin (d2) in combination.

  When the halogenated bisphenol A type epoxy resin (d1) and the halogenated polyacrylate resin (d2) are used in combination, the content of the component (d1) is 3 to 40% by mass in the total amount of the halogen flame retardant (D). The content of the component (d2) is preferably 60 to 97% by mass in the total amount of the halogen-based flame retardant (D). When the component (d1) is 3% by mass or more (when the component (d2) is 97% by mass or less), the impact strength of the resin molded product tends to be good. Further, when the component (d1) is 40% by mass or less (when the component (d2) is 60% by mass or more), the releasability during molding tends to be good.

The lower limit of the content of the component (d1) is more preferably 5% by mass or more, and particularly preferably 7% by mass or more. Further, the upper limit of the content of the component (d1) is more preferably 30% by mass or less, and particularly preferably 25% by mass or less.
(D2) 70 mass% or more is more preferable, and, as for the lower limit of content of a component, 75 mass% or more is especially preferable. Moreover, 95 mass% or less is more preferable, and, as for the upper limit of content of (d2) component, 93 mass% or less is especially preferable.

式（１）中、Ｘはハロゲンを表し、ｍは１〜５の整数を表す。 The halogenated polyacrylate resin (d2) is a compound having the following general formula (1) as a repeating unit.

In formula (1), X represents a halogen, and m represents an integer of 1 to 5.

The halogenated polyacrylate resin (d2) is preferably a pentabromophenyl polyacrylate in which X in the formula (1) is bromine and m = 5 from the viewpoint of flame retardancy.
The number average molecular weight of the halogenated polyacrylate resin (d2) is not particularly limited, but is preferably 500 to 1,000,000. When the number average molecular weight of the halogenated polyacrylate resin (d2) is 500 or more, the thermal stability tends to be good, and when it is 1,000,000 or less, the flowability of the resin composition is good and the moldability is good. It tends to be. The lower limit of the number average molecular weight of the halogenated polyacrylate resin (d2) is more preferably 700 or more, preferably 1000 or more, and particularly preferably 5000 or more. The upper limit is more preferably 500,000 or less, further preferably 100,000 or less, and particularly preferably 50,000 or less.

  Content of a halogenated flame retardant (D) is 5-66 mass% in the resin composition whole quantity. When the content of component (D) is 5% by mass or more, sufficient flame retardancy tends to be obtained, and when the content of component (D) is 66% by mass or less, sufficient conductivity is obtained. And releasability tend to be obtained. (D) As for the lower limit of content of a component, 10 mass% or more is preferable. Further, the upper limit of the content of the component (D) is preferably 40% by mass or less, more preferably 30% by mass or less, and particularly preferably 20% by mass or less.

  The resin composition of the present invention contains the above-described components (A) to (D) as basic components, but if necessary, other thermoplastic resins (however, the components (A) and (B) Component and (D) component), conductive filler (excluding carbon fiber (C)), flame retardant aid, various fillers, particulates such as metal oxides and ceramics, flow modifiers, mold release Additives such as agents, antioxidants, UV absorbers and the like can be added.

Although it does not restrict | limit especially as another thermoplastic resin, Thermoplastic polyester resins other than (A) component and (B) component are mentioned. For example, polyethylene terephthalate which is a polycondensate of terephthalic acid and ethylene glycol, polyethylene naphthalate which is a polycondensate of 2,6-naphthalenedicarboxylic acid and ethylene glycol, 2,6-naphthalenedicarboxylic acid and 1,4- And polybutylene naphthalate which is a polycondensate with butanediol.
Furthermore, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, p-oxybenzoic acid, sebacic acid, adipic acid, dimer Dicarboxylic acid or an ester-forming derivative component thereof appropriately combined with an acid, etc., and glycols such as 1,4-butanediol, ethylene glycol, ethylene oxide, trimethylene glycol, hexamethylene glycol, decamethylene glycol, cyclohexanedimethanol A polycondensation product with a glycol component obtained by appropriately using a combination thereof is also included.

  The content of the thermoplastic polyester resin other than the component (A) and the component (B) is not particularly limited, but is preferably 30% by mass or less in the total amount of the resin composition.

In addition to the thermoplastic polyester resin, for example, a fluorine-containing polymer may be contained for the purpose of imparting abrasion resistance or preventing dripping during combustion.
The fluorine-containing polymer is not particularly limited. For example, polytetrafluoroethylene (abbreviated as PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene. -Ethylene copolymer, trifluorochloroethylene-ethylene copolymer, polytrifluorochloroethylene, polyvinylidene fluoride, polyvinyl fluoride resin and the like. Among these, polytetrafluoroethylene polymers are particularly preferable from the viewpoint of imparting wear resistance and drip resistance.

As these fluorine-containing polymers, commercially available products can be used. As polytetrafluoroethylene-based polymers for wear resistance, SG-1000, SG-500, SA- manufactured by Sanko Fine Material Co., Ltd. 60, Daikin Industries, Ltd. Lubron L-5, Mitsui DuPont Fluorochemical Co., Ltd. Zonyl MP1300, Asahi Glass Co., Ltd. G-169J, etc. In addition, polytetrafluoroethylene heavy for the purpose of dripping resistance Examples of coalescence include METABLEN A3000 and A3800 manufactured by Mitsubishi Rayon Co., Ltd. and Aflon PTFE CD-1 manufactured by Asahi IC Fluoropolymers. These may be used alone or in combination of two or more.
Although content in particular of a fluorine-containing polymer is not restrict | limited, It is preferable that it is 0.1-15 mass% in the resin composition whole quantity.

The conductive filler (excluding carbon fiber (C)) is not particularly limited, and examples thereof include a carbon-based conductive filler and a metal-based conductive filler.
Examples of the carbon-based conductive filler include carbon black, carbon nanotube, and flake graphite. From the viewpoint of the wearability of the molded product, it is preferably 0.1 to 10% by mass or less in the total amount of the resin composition. .
Examples of the metal conductive filler include powders such as copper, tin, brass, stainless steel, iron, and aluminum, and fibrous fillers. Of these, it is preferable to use a tin-based low melting point metal or copper or brass fiber or powder in combination.
It is preferable that a metal type conductive filler is 1-30 mass% in the resin composition whole quantity from a lightweight viewpoint of a molded article.

Although it does not restrict | limit especially as a flame retardant adjuvant, the antimony compound which raises a flame retardant effect by combined use with a brominated flame retardant, and the fluorine-containing polymer which prevents dripping (dripping) at the time of combustion are mentioned, and these are used together It is preferable to do. Antimony compounds include antimony oxide compounds such as antimony trioxide and antimony pentoxide, metal antimonates such as sodium antimonate and magnesium antimonate, and antimonates such as ammonium antimonate, among which antimony trioxide is used. It is preferable.
Although content in particular of an antimony compound is not restrict | limited, It is preferable that it is 1-30 mass% in the resin composition whole quantity. The lower limit of the content of the antimony compound is more preferably 3% by mass or more, and particularly preferably 5% by mass or more. The upper limit is more preferably 20% by weight or less, and particularly preferably 10% by weight or less.

  The content of additives such as various fillers, particulates such as metal oxides and ceramics, flow modifiers, mold release agents, antioxidants, ultraviolet absorbers, etc. is not particularly limited, but is 0 in the total amount of the resin composition. It is preferable that it is 1-30 mass%.

The crystallization temperature of the resin composition of the present invention is not particularly limited, but it is preferable that the peak temperature of the crystallization peak when the temperature is lowered by DSC is 170 ° C. or higher. When this temperature is 170 ° C. or higher, solidification by crystallization at the time of molding is sufficient, and the mold release property tends to be good.
The lower limit of the peak temperature of the crystallization peak when the temperature is lowered by DSC of the resin composition and the resin molded product of the present invention is preferably 172 ° C. or higher, and particularly preferably 175 ° C. or higher.
Further, the upper limit of the peak temperature of the crystallization peak at the time of temperature drop by DSC of the resin composition and the resin molded product of the present invention is not particularly limited, but is preferably 215 ° C. or less, particularly 210 ° C. or more. preferable.

About the manufacturing method of the resin composition of this invention, it does not restrict | limit in particular, It can manufacture with the equipment and method generally used as a manufacturing method of the conventional thermoplastic resin composition. Among them, the melt kneading method is preferable. The apparatus used for melt kneading is not particularly limited, and examples thereof include an extruder, a Banbury mixer, a roller, and a kneader.
As the extruder, there are a single screw extruder and a twin screw extruder, but a twin screw extruder is preferable in order to perform kneading in a short time.
Further, the method for charging the carbon fiber into the extruder is not particularly limited, but the side feed method of adding from the middle of the screw is preferable because the decrease in the fiber length due to kneading can be suppressed.

Next, the resin molded product of the present invention will be described.
The resin molded product of the present invention has a flexural modulus of 3000 to 7500 MPa or less. In the present invention, the flexural modulus is measured by ISO178.
When the flexural modulus of the resin molded product is 3000 to 7500 MPa, shock absorption due to deformation becomes sufficient, and even if the resin molded product of the present invention is used for a bumper of a small HDD, the internal mechanical parts tend not to be destroyed. . This is because shock absorption is manifested by deformation of the material, so that a hard material with little deformation (a material with a high elastic modulus) has almost no shock absorption, and a soft material (a material with a low elastic modulus) has a good shock absorption.
The upper limit value of the flexural modulus of the resin molded product is preferably 7300 MPa or less, particularly preferably 7000 MPa or less. Further, the lower limit value of the flexural modulus is preferably 3500 MPa or more, and particularly preferably 4000 MPa or more.

The resin molded product of the present invention has a Charpy strength of 60 kJ / m ² or more. In the present invention, the Charpy strength is a strength without a notch measured by ISO179.
When the Charpy strength of the resin molded product is 60 kJ / m ² or more, shock absorption is sufficient, and even when the resin molded product of the present invention is used for a bumper of a small HDD, there is a tendency that the resin molded product is not damaged when being attached or detached.
The lower limit of Charpy strength of a resin molded article is preferably 65 kJ / ^{m 2} or more, 70 kJ / ^{m 2} or more is particularly preferable. Moreover, it is preferable that the upper limit of the Charpy strength is not destroyed (NB).

The resin molded product of the present invention has a surface resistance value of 1000Ω or less. In the present invention, the surface resistance value is a resistance value measured between two points using a probe-type terminal.
When the surface resistance value of the resin molded product is higher than 1000Ω, it is insufficient to ground the current from the outside. When the resin molded product of the present invention is used for a bumper of a small HDD, the inside of the HDD The electronic circuit is shorted. The upper limit value of the surface resistance value of the resin molded product is preferably 900Ω or less, and particularly preferably 700Ω or less.
The lower limit of the surface resistance value of the resin molded product is not particularly limited, but is preferably 1Ω or more, and particularly preferably 10Ω or more.

  The resin molded product of the present invention has a flame retardance of V-1 or more at a thickness of 0.8 mm. In addition, a flame retardance is measured according to the method of the subject 94 (UL94) of Underwriters Laboratories. The flame retardant level is particularly preferably V-0.

The resin molded product having such physical properties is 25 to 86% by mass of the polyester elastomer (A), 2 to 63% by mass of polybutylene terephthalate (B), 7 to 30% by mass of carbon fiber (C), and halogenated. It can manufacture by shape | molding the resin composition containing 5-66 mass% of halogenated flame retardants (D) containing a bisphenol A type epoxy resin (d1).
The molding method of the resin composition is not particularly limited. Examples include injection molding, extrusion molding, rod-shaped, hollow, and sheet-shaped molding, vacuum molding, blow molding, and the like. A resin molded product can be obtained by these molding methods.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to a following example.
(1) Evaluation Method of Resin Composition and Resin Molded Product (1-1) Crystallization Peak Temperature at Temperature Decreasing by DSC Measured using a differential scanning calorimeter DSC SSC / 5200 manufactured by Seiko Instruments Inc. The resin composition was heated from 25 ° C. to 10 ° C./min in a nitrogen stream and held at 280 ° C. for 5 minutes, and then the temperature was lowered at 10 ° C./min to determine the crystallization peak temperature during temperature reduction.

(1-2) Flexural modulus A flexural test was performed in accordance with ISO178 to determine the flexural modulus.
(1-3) Charpy Strength A Charpy strength test without a notch was performed in accordance with ISO 179 to determine Charpy strength.
(1-4) Surface resistance value About the ISO dumbbell-type test piece used for the bending test, the surface resistance value between two points was measured using a probe type terminal. (Measures the center of the dumbbell along the flow direction using an Advantest high resistivity meter)

（１−６）離型性
上記（１−５）で作成する厚み０．８ｍｍの試験片を作成する際に、金型からはがれやすいかどうかにより評価した。
○：突き出しピンにより剥離する。
×：突き出しピンにより剥離しない。
（１−７）落下衝撃テスト
１インチＨＤＤの樹脂バンパー形状に成形し、樹脂バンパーに絶縁シートを貼り付けて小型ＨＤＤに組み込んだ。この小型ＨＤＤを２ｍの高さからコンクリート床に落下させ、データを正常に読み出せるかどうかにより評価した。
○：データを読み出せる。
×：データを読み出せない。 (1-5) Flame retardant test (UL-94)
In accordance with the method of Subject 94 (UL94) of Underwriters Laboratories, using five test pieces (thickness: 0.8 mm), the flame retardancy and the dripping characteristics accompanying the combustion of the resin composition were tested and burned. The level was evaluated.

(1-6) Releasability When the test piece having a thickness of 0.8 mm prepared in the above (1-5) was prepared, it was evaluated based on whether or not it was easily peeled off from the mold.
○: Peeled by the protruding pin.
X: It does not peel off by the protruding pin.
(1-7) Drop Impact Test A 1-inch HDD was molded into a resin bumper shape, and an insulating sheet was attached to the resin bumper and incorporated into a small HDD. This small HDD was dropped from a height of 2 m onto a concrete floor, and an evaluation was made based on whether data could be read normally.
○: Data can be read.
×: Data cannot be read.

(1-8) Desorption Test A small HDD manufactured by the same method as in (1-7) above was evaluated by whether or not the bumper was damaged by repeating insertion and extraction 100 times.
○: No damage to the bumper.
X: The bumper is damaged.
(1-9) Electric shock test A small HDD manufactured by the same method as in (1-7) above is placed on a grounded metal plate, and charged at 8.5 kV 160 times (each of the four corners on the front and back sides). Evaluation was made based on whether or not the data could be normally read out by touching 20 times each).
○: Data can be read.
×: Data cannot be read.

(2) Raw materials used in the examples (2-1) Polyester elastomer (A)
A-1 Perprene GP300 (a polyether polyester elastomer manufactured by Toyobo Co., Ltd.)
A-2 Perprene GP500 (Polyether polyester elastomer manufactured by Toyobo Co., Ltd.)
(2-2) Polybutylene terephthalate (B)
NOVADURAN 5008 (PBT intrinsic viscosity [η] manufactured by Mitsubishi Engineering Plastics Co., Ltd. is 0.9 dl / g)

(2-3) Carbon fiber (C)
C-1 (TR06UB3E manufactured by Mitsubishi Rayon Co., Ltd. Chopped carbon fiber. Fiber diameter 7 μm, primary sizing agent, epoxy system, secondary sizing agent polyurethane system, tensile elastic modulus 235 GPa, fiber length 6 mm, convergence number 12000, volume resistivity 1. 5 × 10 ⁻³ Ωcm.)
C-2 (TR06 NEB3E, chopped carbon fiber manufactured by Mitsubishi Rayon Co., Ltd. Fiber diameter 7 μm, primary sizing agent, epoxy type, secondary sizing agent polyamide type, tensile elastic modulus 235 GPa, fiber length 6 mm, convergence number 12,000, volume resistivity 1. 5 × 10 ⁻³ Ωcm.)

(2-4) Flame retardant (D)
d1-1 SR-T20000 (Sakamoto Yakuhin Kogyo Co., Ltd. halogenated bisphenol A type epoxy resin number average molecular weight 30000 both terminal epoxy type)
d1-2 SR-T104N (Sakamoto Yakuhin Kogyo Co., Ltd. halogenated bisphenol A type epoxy resin number average molecular weight 1000 50% end-capped type with tribromophenol)
d2-1 FR-1025 (Bromochem Far East, pentabromophenyl polyacrylate number average molecular weight 8000)
D'-1 FG-7500 (Carbon oligomer of tetrabromobisphenol A manufactured by Teijin Chemicals Ltd.)

(2-5) Other components Carbon black (C ′): Conductex 975 (Conductive carbon black manufactured by Colombian Carbon Japan)
Abrasion resistance imparting agent: ACEFLON SG-1000 (Miyuki Fine Materials Co., Ltd. finely pulverized PTFE: PTFE produced by suspension polymerization and pulverized after radiation treatment)
Flame retardant aid: Patox M (Nippon Seika Co., Ltd. antimony triacid)
Anti-dripping agent: Metabrene A3800 (PTFE-containing polymer manufactured by Mitsubishi Rayon Co., Ltd.)
Filler: Micron White # 5000A (Talc manufactured by Hayashi Kasei)
Antioxidant: ADK STAB AO-60 (Asahi Denka Kogyo Co., Ltd. hindered phenol antioxidant), ADK STAB 2112 (Asahi Denka Kogyo thioether antioxidant)
Release agent: LICOWAX-OP (release agent made by Clariant Japan Ltd. Partially saponified ester of montanic acid)

Examples 1-8 and Comparative Examples 1-11
Using a twin screw extruder (PCM-30 manufactured by Ikegai Seisakusho), components other than the carbon fibers shown in Tables 1 and 2 are supplied from a resin feeder, and carbon fibers are supplied from a side feeder. Of a resin composition containing a polyester elastomer (A), polybutylene terephthalate (B), carbon fiber (C), halogen flame retardant (D), and other components which are melt-kneaded at ℃ (resin temperature 290 ° C.) Pellets were obtained. Here, the water was removed by reducing the pressure from the vent port provided in the middle of the extruder.
Next, the pellets were dried with hot air at 150 ° C. for 2 hours, and various test pieces were prepared using an injection molding machine (Mitsubishi Heavy Industries 75T injection molding machine) at a resin temperature of 260 ° C. and a mold temperature of 80 ° C. Molded. The evaluation results of the resin composition and the molded product are shown in Tables 2-3.

  The molded article of the present invention can be used in the electric and electronic fields such as magnetic heads, ICs, and hard disks that require shock absorption, conductivity, and flame retardancy, and as a resin bumper for small hard disk drives, among others. It can be preferably used.

Claims (4)

  Halogen system containing 25 to 86% by mass of polyester elastomer (A), 2 to 63% by mass of polybutylene terephthalate (B), 7 to 30% by mass of carbon fiber (C), and halogenated bisphenol A type epoxy resin (d1) A resin composition containing 5 to 66% by mass of a flame retardant (D).   The resin composition according to claim 1, wherein the halogenated bisphenol A type epoxy resin (d1) has a number average molecular weight of 15000 or more.   The resin composition according to claim 1, wherein the halogen flame retardant (D) comprises 3 to 40% by mass of a halogenated bisphenol A type epoxy resin (d1) and 60 to 97% by mass of a halogenated polyacrylate resin (d2). A resin molded product having a flexural modulus of 3000 to 7500 MPa or less, a Charpy strength of 60 kJ / m ² or more, a surface resistance value of 1000 Ω or less, a flame retardance of 0.8 mm and a V-1 or more.