JPH09286876A - Holding member for information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holding member for an information recording medium which member exhibits a high coefficient of friction on and a weal adhesion to an information recording material and is excellent in thermal fusion with a nonolefinic thermoplastic resin material (e.g. a PC resin). SOLUTION: This holding member is obtd. by molding a thermoplastic elastomer compsn. comprising 10-90 pts.wt. nonpolar thermoplastic elastomer and 10-90 pts.wat. thermoplastic elastomer which has a JIS a hardness of 85 or higher and of which the hard component is composed of polar segments.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a holding member for an information recording medium. More specifically, the present invention relates to a holding member for fixing an information recording medium such as paper, an optical disk, a magnetic disk, a magnetic tape, etc. at a predetermined position, or moving the information recording medium at an accurate position, specifically, a video disk, a CD-ROM.
Information disc turntables, pinch rollers for audio tape recorders, video tape recorders, paper feeding rollers for copying machines and printers.

[0002]

2. Description of the Related Art A holding member for driving an information medium in an information recording / reproducing apparatus, for example, a turntable 1 of a CD-ROM is mounted on the tip of a rotating drive shaft 2 as shown in FIG. Has a disk-shaped support base 3, and an annular soft ring 4 is fixed to the upper surface of the support base 3,
An information recording medium disk 5 such as a CD-ROM is held by a soft ring 4 and a clamper 6 and rotated.

Since the information recording medium disk 5 and the support base 3 are required to have a high degree of dimensional accuracy, an amorphous engineering plastic material, especially polycarbonate (hereinafter abbreviated as PC resin) is mainly used as the material. Has been done. Further, the soft ring 4 has a low hardness and an appropriate friction coefficient in order to maintain a sufficient holding force of the information disc at the time of high-speed rotation, and the contamination of the disc due to the sticking property to the information disc and the disc It is required to have low resistance when removing. Therefore, conventionally, a support base made of PC resin is coated with urethane (JP-A-3-185035), or a sheet-shaped thermosetting rubber such as chloroprene rubber is attached through an adhesive tape or the like. There is.

However, in these methods, the manufacturing process is complicated, so that the cost is high, and the coefficient of friction with the disk becomes insufficient as the number of rotations of the desk increases, and the information disk flickers due to the uneven thickness of the coating film. There are problems such as occurrence. A pinch roller that drives a magnetic tape, which is an information medium such as a VTR, is a roller that press-holds the magnetic tape between a facing drive motor shaft and transmits the motor driving force to the magnetic tape. The required performance of the holding material is, as in the case of the turntable, low hardness, high friction coefficient with the magnetic tape, low sticking property, and heat-sealing property with the sleeve as the supporting member. According to the current technology, since surface-treated chloroprene rubber is baked on a metal sleeve, a complicated manufacturing process is required, resulting in high cost.

On the other hand, thermoplastic elastomers (hereinafter TPE
Has a low hardness, a high coefficient of friction, and excellent moldability. Therefore, when a TPE material is used for a soft part, it can be laminated with a support member by insert molding or two-color molding. If there is, it is advantageous in terms of cost and dimensional accuracy. However, the conventional TPE cannot be used because the heat fusion property and the characteristics required as a holding component for the information recording medium cannot be achieved at the same time.

For example, a non-polar elastomer such as a styrene elastomer or an olefin elastomer has low hardness and little sticking property to an information recording medium, but on the other hand, it is sufficiently heat-sealed to a supporting resin material such as a PC resin or a metal material. Not. On the other hand, polar elastomers such as ester-based, amide-based, and urethane-based elastomers are excellent in heat-sealing property to the substrate, but those having low hardness and high friction coefficient sufficient to hold the information medium under pressure are PC resin information discs. It has a very strong sticking property to and cannot be used.

[0007]

The present invention has a low hardness,
With a high coefficient of friction and a low sticking property to the information recording medium, and also to develop a holding member for the information recording medium, which has an excellent heat fusion property to a non-olefinic thermoplastic resin material such as a PC resin. investigated.

[0008]

Means for Solving the Problems The present invention has been earnestly studied to solve the above problems, and as a result, information obtained by molding a thermoplastic elastomer composition comprising the following components (a) and (b) The holding member for a recording medium has low hardness and a high friction coefficient, but has little sticking property to an information medium, and has excellent heat fusion property with a non-olefinic thermoplastic resin such as a PC resin. It was made by discovering that it has both. Component (a) Non-polar thermoplastic elastomer 10 to 90 parts by weight Component (b) JIS-A Thermoplastic elastomer composed of a segment having a hardness of 85 or more and a hard component containing a polar group 10 to 90 parts by weight

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) Component (a) Nonpolar Thermoplastic Elastomer The nonpolar TPE in the present invention has a flexural modulus of less than 5,000 kg / cm ² , preferably less than 4,000 kg / cm ² , and more preferably 3 according to JIS-K7203. ，
It is less than 000 kg / cm ² . Specifically, olefin-based TPE, styrene-based TPE, etc. can be used.

A) Olefin-based thermoplastic elastomer (olefin-based TPE) The olefin-based TPE used in the present invention is an olefin-based copolymer rubber such as ethylene / propylene copolymer rubber (EPM) or ethylene / propylene / non-conjugated rubber. Basically, an elastic body of an amorphous random copolymer containing olefin as a main component such as diene copolymer rubber (EPDM) or an elastic body obtained by heat-treating them in the presence of an organic peroxide and mainly crosslinking by radicals. It is contained as an ingredient.

Examples of such an olefinic copolymer rubber used in the present invention include the above-mentioned ethylene / propylene copolymer rubber (EPM), ethylene / 1-butene copolymer rubber (EBM) and ethylene / propylene / butene copolymer rubber. Rubber, ethylene, hexene copolymer, ethylene / heptene copolymer, ethylene / octene copolymer, ethylene / 4
-Methylpentene-1 copolymers and non-conjugated dienes such as butene-1,1,4-hexadiene and other aliphatic dienes, 5-ethylidene norbornene, 5-methyl norbornene, 5-vinyl norbornene, dicyclopentadiene, diene Examples thereof include ethylene / propylene / non-conjugated diene copolymer rubbers using cyclooctadiene and the like.

These copolymers or copolymer rubbers may be any of random copolymers, block copolymers, graft copolymers and alternating copolymers, and their production method and shape are not particularly limited. . Further, these olefin-based copolymer rubbers may be used not only as a single component but also as a combination of a plurality of components. These olefin-based copolymer rubbers have a weight average molecular weight of 50,000 to 1,000,000.
0, preferably 60,000 to 800,000, particularly preferably 80,000 to 500,000, an ethylene content of 30 to 90% by weight, preferably 40 to 85% by weight,
It is preferable to use a copolymer rubber having a Mooney viscosity ML _{1 + 4} (100 ° C.) of 5 to 400, preferably 10 to 350.

If the weight average molecular weight of the ethylene / propylene copolymer rubber is less than the above range, the rubber elasticity and mechanical strength are poor, and if the weight average molecular weight exceeds the above range, the moldability is poor. It is not preferable. Here, the “weight average molecular weight” is a polypropylene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions. The universal method was used for conversion into polypropylene. The viscosity formula used at this time is as follows.

[0014]

## EQU1 ## [η] ps = 1.079 × 10 ^-4 M ^0.723 [η] pp = 2.42 × 10 ^-4 M ^0.707 Column: polystyrene mix gel column (AD80M
/ S (Showa Denko KK) 3) Solvent: o-dichlorobenzene Temperature: 140 ° C Flow rate: 1 ml / min Injection volume: 200 μl Concentration: 2 mg / ml (antioxidant 2,6-di 0.2% by weight of -t-butyl-p-phenol was added, and the concentration was detected by an infrared spectrophotometer at a wavelength of 3.42 μm.)

The olefinic TPE contained as the olefinic copolymer rubber base is, for example, "Thermoran" manufactured by Mitsubishi Chemical Co., Ltd., "Milastomer" manufactured by Mitsui Petrochemical Industry Co., Ltd., Sumitomo Chemical Co., Ltd. It can be obtained from the market as "Sumitomo TPE" manufactured by Co., Ltd., "Santplane" manufactured by Advanced Elastomer Systems, and the like.

(B) Styrene-based thermoplastic elastomer (styrene-based TPE) The styrene-based thermoplastic elastomer used in the present invention includes a hydrogenated product of a styrene / butadiene block copolymer or a hydrogenated product of a styrene / isoprene block copolymer. Alternatively, those containing as a basic component a hydrogenated product of a styrene / conjugated diene block copolymer selected from a mixture thereof can be used.

The hydrogenated product of the styrene / conjugated diene block copolymer is a polymer block in which the conjugated diene is butadiene alone, isoprene alone, or a mixture of isoprene and bradiene, and specifically, styrene. A hydrogenated product of a butadiene / styrene block copolymer (hereinafter sometimes simply referred to as "hydrogen S-B-S"), a hydrogenated product of a styrene / isoprene / styrene block copolymer (hereinafter simply referred to as "water"). Appendix S-I-
It may be abbreviated as "S". Or a hydrogenated product of a styrene-isoprene-butadiene-styrene block copolymer (hereinafter may be simply abbreviated as “hydrogenated S-BI-S”).

The hydrogenated products of these styrene / conjugated diene block copolymers have a weight average molecular weight of 50,000-
500,000, preferably 120,000 to 450,
000, particularly preferably 150,000 to 400,000
0, styrene content is 5 to 50% by weight, preferably 8 to
45% by weight, particularly preferably 10-40% by weight, 1,2
Block copolymers having a microstructure of less than 50%, preferably 0-45% and a hydrogenation rate of 95% or more, preferably 97% or more are used. Where "weight average molecular weight"
Is a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions. As the rehabilitation curve, monodisperse polystyrene was used.

(Condition) Column: Polystyrene mix gel column (A
D80M / S (manufactured by Showa Denko KK) 3) Solvent: o-dichlorobenzene Temperature: 140 ° C Flow rate: 1 ml / min Injection volume: 200 μl Concentration: 2 mg / ml (antioxidant 2,6-di- 0.2% by weight of t-butyl-p-phenol was added, and the concentration was detected by an infrared spectrophotometer at a wavelength of 3.42 μm).

If the weight-average molecular weight of the hydrogenated styrene / conjugated diene block copolymer is less than 50,000, rubber elasticity and mechanical strength are poor, and if it exceeds 500,000, moldability tends to be poor. Become. As a method for producing a hydrogenated product of these styrene / conjugated diene block copolymers, for example, a method described in JP-B-40-23798 is used, and a styrene / conjugated diene block is used in an inert solvent using a lithium catalyst. Synthesize a copolymer,
Next, for example, Japanese Patent Publication No. 42-8704 and Japanese Patent Publication No. 43
-6636, JP-A-59-133203, JP-A-6
According to the method described in each publication of 0-79005, a method of hydrogenating in the presence of a hydrogenation catalyst in an inert solvent can be mentioned.

Further, hydrogenated S-I-S and hydrogenated S-BI
-S is disclosed in JP-A-2-102212 and JP-A-3-1321.
88114, i.e., styrene and isoprene or isoprene-butadiene for total monomer 10
0.01 to 0.2 part by weight of an alkyl lithium compound as an initiator and 0.04 to 0.8 part by weight of a coupling agent, and 0.
Obtained by sequentially polymerizing in the presence of 1 to 400 parts by weight of a Lewis base at −20 to 80 ° C. for 1 to 50 hours in an inert catalyst, and then hydrogenating an isoprene or isoprene-butadiene block.

Examples of commercially available products include "Clayton G" manufactured by Shell Japan Co., "Septon""HighBlur" manufactured by Kuraray Co., Ltd., "Tuftec" manufactured by Asahi Kasei Kogyo Co., Ltd. and "Dynaron" manufactured by Japan Synthetic Rubber Co., Ltd. In addition, styrene-based thermoplastic elastomers containing hydrogenated products of these styrene / conjugated diene block copolymers are, for example, "Lavalon" manufactured by Mitsubishi Chemical Co., Ltd., "Clayton G compound" manufactured by Shell Japan Co., Ltd. , "Septon Compound" manufactured by Kuraray Co., Ltd., "Tough Tech Compound E Series, S Series" manufactured by Asahi Kasei Co., Ltd., and the like. The non-polar thermoplastic elastomer used in the present invention has a JIS-A hardness (JISK630
It is desirable that 1) is 90 or less, preferably 80 or less because the hardness of the molded member made of the composition with the component (b) is low and the friction coefficient is high.

(2) Component (b) Polar Thermoplastic Elastomer The polar thermoplastic elastomer of the present invention is a thermoplastic elastomer composed of a crystal structure of a segment in which the hard component has a polar group, and examples thereof include polyesters and polyamides. And polyurethane-based elastomers are used. A) Polyester thermoplastic elastomer The polyester elastomer of the present invention is JIS-K7.
The flexural modulus according to 203 is 10,000 kg / cm ² or less. It is preferably 0 to 6,000 kg / cm ² , and particularly preferably 100 to 6,000 kg / cm ² . For such polyester elastomer, an aromatic polyester is used as a hard component, a polyester polyether block copolymer using an aliphatic polyether as a soft component, an aromatic polyester is used as a hard component, and an aliphatic polyester is used as a soft component. Polyester A polyester block copolymer is mentioned.

(Polyester polyether block copolymer) The polyester polyether block copolymer is
An esterification reaction using an aliphatic and / or alicyclic diol having 2 to 12 carbon atoms, an aromatic dicarboxylic acid or an alkyl ester thereof, and a polyalkylene ether glycol having a weight average molecular weight of 400 to 6,000 as raw materials, Alternatively, it is obtained by polycondensing an oligomer obtained by a transesterification reaction.

As the aliphatic and / or alicyclic diol having 2 to 12 carbon atoms used in the present invention, those known as raw materials for polyester, particularly polyester elastomer can be used, and examples thereof include ethylene glycol and propylene. Glycol, trimethylene glycol,
Examples thereof include 1,4-butanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol, and preferably 1,4-butanediol, ethylene glycol, and particularly preferably 1,4-butanediol. It is used as a component, and one kind or two or more kinds can be used.

As the aromatic dicarboxylic acid, those known as a raw material of polyester, particularly a raw material of polyester elastomer can be used, and terephthalic acid, isophthalic acid,
2,6-naphthalenedicarboxylic acid and the like can be mentioned, preferably terephthalic acid and 2,6-naphthalenedicarboxylic acid, particularly preferably terephthalic acid as a main component, and two or more of these are used in combination. You may.
Examples of the alkyl ester of aromatic dicarboxylic acid include dimethyl esters such as dimethyl terephthalate, dimethyl isophthalate, dimethyl phthalate and 2,6-dimethyl naphthalate, and dimethyl terephthalate and 2,6-dimethyl naphthalate are preferable. And particularly preferably dimethyl terephthalate,
These can be used in combination of two or more. In addition to the above, small amounts of trifunctional diols, other diols and other dicarboxylic acids and their esters may be copolymerized, and further, aliphatic dicarboxylic acids such as adipic acid or alicyclic dicarboxylic acids, or Alkyl ester etc. may also be used as a copolymerization component.

As the polyalkylene ether glycol, those having a weight average molecular weight of 400 to 6,000 are used, preferably 500 to 4,000, particularly preferably 600 to 3,000. Molecular weight 400
If it is less than 3, the blockability of the copolymer will be insufficient, and if the weight average molecular weight exceeds 6,000, the physical properties of the polymer will decrease due to phase separation in the system. Here, as the polyalkylene ether glycol, polyethylene glycol, poly (1,2,1,3 propylene ether) glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, a block or random copolymer of ethylene oxide and propylene oxide. , A block or random copolymer of ethylene oxide and tetrahydrofuran. Particularly preferred is polytetramethylene ether glycol. The content of the polyalkylene ether glycol is preferably 5 to 95% by weight, more preferably 10 to 85% by weight, and particularly preferably 20 to 80% by weight, based on the resulting block copolymer. desirable. If the content is more than 95% by weight, it is difficult to obtain a polymer by condensation polymerization.

(Polyester / polyester block copolymer) The polyester / polyester block copolymer of the present invention has a weight average molecular weight of 400 to 6,0.
Instead of 00 polyalkylene ether glycol,
Polyester oligomer condensed with aliphatic or alicyclic dicarboxylic acid and aliphatic diol, polyester oligomer synthesized from aliphatic lactone or aliphatic monoolcarboxylic acid, and aliphatic and / or alicyclic group having 2 to 12 carbon atoms This is a product obtained by polycondensing an oligomer obtained by an esterification reaction or a transesterification reaction using a formula diol and an aromatic dicarboxylic acid or its alkyl ester as raw materials.

Examples of 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid,
Alicyclic dicarboxylic acids such as dicyclohexyl-4,4'-dicarboxylic acid or succinic acid, oxalic acid, adipic acid,
Examples include polyester oligomers having a structure in which one or more aliphatic dicarboxylic acids such as sebacic acid and one or more diols such as ethylene glycol, propylene glycol, tetramethylene glycol, and pentamethylene glycol are condensed. Polycaprolactone-based polyester oligomers synthesized from ε-caprolactone, ω-oxycaproic acid and the like can be mentioned.

(Production Method of Polyester Elastomer) The esterification, transesterification and polycondensation reaction in the present invention can be carried out according to a conventional method. As the catalyst in these reactions, one or two or more known catalysts such as alcoholates such as tin, titanium, zinc and manganese, chlorides, oxides, etc. can be used, respectively. Catalysts, especially tetrabutyl titanate, are desirable. Further, as an auxiliary agent, phosphoric acid, phosphorous acid,
Hypophosphorous acid or metal salts thereof may be added. In particular, it is preferable to add an alkali metal hypophosphite since the content of terminal carboxyl groups is reduced and the hydrolysis resistance is improved.

Examples of the alkali metal hypophosphite include sodium hypophosphite, potassium hypophosphite, lithium hypophosphite and the like, and sodium hypophosphite is particularly desirable. The amount of the alkali metal hypophosphite added is 1 to 1,000 ppm, preferably 3 to 200 ppm, more preferably 5 to 80 ppm, based on the produced polymer. If it is less than 1 ppm, the effect of the addition cannot be sufficiently obtained, and if it is added more than 1,000 ppm, the effect is not changed but the polycondensation reaction is inhibited, which is not preferable.

As an addition method, the alkali metal hypophosphite may be added to the molten polymer in any of a solution form, a slurry form and a solid form. The addition time is preferably at least before completion of the polycondensation reaction. That is, it may be added at any time between before the esterification reaction or transesterification reaction and before the end of the polycondensation reaction. In particular, it is preferable to add in the form of a slurry immediately before the start of the polycondensation under reduced pressure, since the decrease in polymerizability is small.

Further, other additives may be present in the reaction step. For example, known additives such as a hindered phenol-based oxidation stabilizer, a hindered amine-based oxidation stabilizer, a phosphorus-based oxidation stabilizer, a sulfur-based oxidation stabilizer, and a triazole-based light stabilizer are used. In particular, in the present invention, 0.01 to 1% by weight of the hindered phenol-based oxidation stabilizer is more preferably added to the polymer from the viewpoint of the effect. The esterification or transesterification reaction is usually performed at 120 to 250 ° C., preferably 150 to 230 ° C., and the melt polycondensation reaction is generally performed at 200 to 280 ° C. for 2 to 6 hours under a reduced pressure of 10 torr or less.

Usually, the polymer obtained by melt polymerization is
The temperature is maintained at a temperature equal to or higher than the melting point, and discharge and pelletization are sequentially performed from the reactor. The pellets obtained here are:
If necessary, solid phase polymerization may be further performed. As such a polyester polyether block copolymer,
Commercially available polymers such as "Perprene P" (trade name, manufactured by Toyobo Co., Ltd.), "Hytrel" (trade name, manufactured by Dupont Toray), "Lomod" (trade name, manufactured by Nippon GE Plastics), and "Nichigo Polyester" ( Nippon Synthetic Chemical Industry Co., Ltd.), Teijin Polyester Elastomer
(Trade name, manufactured by Teijin Limited), and the polyester-polyester block copolymer includes “Perprene S” (trade name, manufactured by Toyobo Co., Ltd.) which is a commercially available polymer.

(B) Polyamide-based thermoplastic elastomer As the polyamide-based thermoplastic elastomer, polyamide (nylon 6,66, 11, 12, etc.) is used as a hard segment, and polyether or polyester is used as a soft segment. For example, the polyether block amide is represented by the following general formula [I]. General formula [I]

[0036]

Embedded image

(PA in the formula represents a block of polyamide which is a hard segment, and PG represents a block of polyether which is a soft segment.) It is represented by the chemical formula represented by the above general formula [I] used in the present invention. The polyether block amide described above is a substance known per se as disclosed in US Pat. No. 3,044,978 and the like.

Examples thereof include (a) salts of diamine and dicarboxylic acid, lactams, or aminodicarboxylic acids (PA constituents), (b) polyoxyalkylene glycols such as polyoxyethylene glycol and polyoxypropylene glycol. It is adjusted by polycondensing the (PG constituent) and (c) dicarboxylic acid. Commercially available products are "Pebax" (trade name of Toray Industries, Inc.), "Daiamide-PAE" (trade name of Daicel-Huls), "UBE Polyamide Elastomer" (trade name of Ube Industries, Ltd.), "Novamitt". PAE "(trade name of Mitsubishi Chemical Co., Ltd.)," Grelax A "(trade name of Dainippon Ink and Chemicals Co., Ltd.)," Guriron ELX, EL
Y ”(trade name of MMS Japan Co., Ltd.) and the like.

C) Polyurethane-based thermoplastic elastomer As the above-mentioned polyurethane-based thermoplastic elastomer, diisocyanate and short-chain glycol (ethylene glycol, propylene glycol, 1,4-butanediol,
Hard segment consisting of (bisphenol A, etc.),
It has a soft segment composed of diisocyanate and a long-chain polyol. As a long-chain polyol,
Poly (alkylene oxide) glycol having a molecular weight of 400 to 6,000 (for example, polyethylene glycol, poly (1,2 and 1,3 propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, etc. ), Or a polyester-based one such as polyalkylene adipate, polycaprolactone, or polycarbonate. This type of polyurethane thermoplastic elastomer is a compound having a structure represented by the following general formula [II]. General formula [II]

[0040]

Embedded image

(A in the formula represents a hard segment composed of diisocyanate and short-chain glycol, B represents a soft segment composed of diisocyanate and long-chain polyol, and Y represents a urethane-bonded diisocyanate compound for connecting A segment and B segment. Represents the residue of.)

As this type of diisocyanate compound, known and conventional compounds such as phenylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, 4,4 'diphenylmethane diisocyanate and hexamethylene diisocyanate are used. As the commercial product of the thermoplastic polyurethane-based elastomer,
"Elastolan" (Takeda Birdish Urethane Co., Ltd. product name), "Miractran" (Nippon Miractoran Co., Ltd. product name), "Resamine P" (Dainichi Seika Chemical Co., Ltd. product name), "U Fine P" (Asahi Glass Co., Ltd. product name).

The above various polar thermoplastic elastomers are
The JIS-A hardness is 85 or more (preferably 90 or more), and when the hardness is lower than this, the sticking property to the medium and the staining property remarkably increase. Of these, polyester-based thermoplastic elastomers and amide-based elastomers are preferable because they are less likely to stick to media and have less stain resistance, and ester-based elastomers are more preferable in terms of compatibility with the component (a).

The compounding ratio of the component (a) non-polar elastomer and the component (b) polar elastomer in the present invention is 10 /.
90-90 / 10, preferably 20 / 80-80 / 20
When the amount of the polar elastomer is less than the above range, the heat fusion property to the non-olefinic thermoplastic resin supporting component becomes insufficient, and conversely, the hardness becomes high. The hardness of the elastomer composition is preferably 90 or less. When the hardness is higher than this, the pressure contact retention of the information recording medium is poor.

(3) Additional compounding material (optional component) The TPE composition described above may be compounded with any compounding component as required. Specifically, softeners for hydrocarbon rubber (average molecular weight 300 to 2,000), various plasticizers, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers,
Various additives such as a neutralizer, a lubricant, an anti-clouding agent, an anti-blocking agent, a slip agent, a crosslinking agent, a crosslinking aid, a colorant, a flame retardant, a dispersant, and an antistatic agent can be added. Further, within a range that does not significantly impair the effects of the present invention, various thermoplastic resins, various elastomers, carbon black, talc, calcium carbonate, diatomaceous earth, glass fibers, glass balloons, compounding materials such as various fillers such as carbon fibers can do.

The hydrocarbon-based softening agent for rubber in the additional compounding material component can play an important role in controlling the processability and flexibility of the olefin-based or styrene-based thermoplastic elastomer composition. . Such a hydrocarbon rubber softener (having an average molecular weight of generally 300 to 2,
000, preferably 500 to 1,500) is preferably blended in an amount of 0 to 250 parts by weight, particularly 20 to 200 parts by weight, based on 100 parts by weight of the olefin-based or styrene-based elastomer.

Such a hydrocarbon-based softening agent for rubber is a mixture in which an aromatic ring, a naphthene ring and a paraffin ring are combined, and the paraffin chain carbon number occupies 50% or more of the total carbon. Is called a paraffin oil, a naphthene ring carbon number of 30 to 45% is called a naphthene oil, and an aromatic carbon number of more than 30% is called an aromatic oil. . Of these, paraffinic oil is preferably used.

As the thermoplastic resin in the above-mentioned additional compounding material component, polypropylene, ethylene resin, polyolefin resin such as polybutene-1 resin, polystyrene, acrylonitrile / styrene copolymer, acrylonitrile / butadiene / styrene copolymer are used. Polystyrene resin such as coalescing, polyphenylene ether resin, polyamide resin such as nylon 6 and nylon 66, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, polyoxymethylene homopolymer, polyoxymethylene copolymer such as polyoxymethylene copolymer Based resins, polymethylmethacrylate based resins and the like can be used.

As the ethylene resin, polyethylene,
Examples thereof include ethylene / α-olefin copolymers, ethylene / vinyl acetate copolymers, ethylene / (meth) acrylic acid copolymers and ethylene / (meth) acrylic acid ester copolymers. Examples of the polyethylene include low-density polyethylene (branched ethylene polymer) and medium density,
High density polyethylene (linear ethylene copolymer) and the like can be mentioned.

One kind of thermoplastic resin may be used,
Multiple types may be used. Generally, 1 to 300 parts by weight, preferably 20 to 250 parts by weight, is preferably added to 100 parts by weight of the hydrogenated product of the olefin copolymer rubber or the styrene / conjugated diene block copolymer.
Further, in order to further reduce the sticking property of the soft part made of the TPE composition of the present invention to the information recording medium, a lubricant,
It is effective to add a slip agent. Examples of lubricants and slip agents include hydrocarbon lubricants such as silicon oil, liquid paraffin, microwax, and polyethylene wax, fatty acid lubricants such as stearic acid and lauric acid, and fatty acids such as stearic acid amide, palmitic acid amide, and oleic acid amide. Amide-based lubricants, metal soaps such as lead stearate, lead salicylate and lauric acid amide, ester-based lubricants such as butyl stearate and ethylene glycol monostearate, and alcohol-based lubricants such as cetyl alcohol and stearyl alcohol can be used. These lubricants are preferably blended in an amount of 0 to 5 parts by weight, preferably 0 to 2 parts by weight, based on 100 parts by weight of the TPE composition. As the method of adding the above-mentioned additional components, the components (a) and (b)
And the additional components may be blended together at the same time, or may be added to the component (a) (or the component (b)) in advance,
It may then be blended with component (b) (or component (a)).

(4) Information recording medium holding member The TPE thus obtained is molded into an information recording medium holding member. The information recording medium covers a wide range of recording materials such as paper, optical discs, magnetic discs, and magnetic tapes, and a member that directly or indirectly contacts the information recording medium in order to fix or accurately run these materials. You can Specifically, it manufactures turntables such as video discs and CD-ROM discs, pinch rollers such as audio tape recorders and video tape recorders, guide rollers, paper feed rollers such as copiers and printers as shown in FIG. can do.

Generally, a support is formed of a hard material, and a holding member made of the TPE composition of the present invention is joined to the surface of the support that contacts the information recording medium. The material used as the support member is preferably a metal or a non-olefinic thermoplastic resin, aromatic polycarbonate, polybutylene terephthalate, polyphenylene sulfide, various polyamides (nylon 6, 66, nylon 610, nylon MXD6, etc.), polyetherimide At least one resin selected from the group consisting of non-olefin resins such as polysulfone, polyether sulfone, acrylic resin, styrene resin, and modified polyphenylene ether, and having a flexural modulus of 15,000 according to JIS-K7203.
0 kg / cm ² or more, preferably 20,000 kg / c
m ² or more. If the flexural modulus is smaller than this, dimensional defects due to bending, resonance at high speed rotation, etc. occur. Above all, a metal or a polycarbonate resin is preferable in terms of a good balance of dimensional accuracy, heat resistance, cost, and heat fusion property with the elastomer soft member of the present invention.

Further, the non-olefin type thermoplastic resin includes
If necessary, additional components can be added. For example, glass fiber, carbon fiber, silica fiber, silica-alumina fiber, potassium titanate fiber, aluminum borate fiber, stainless fiber, inorganic fiber-like reinforcing material such as aluminum fiber, aramid fiber, polyimide fiber, organic resin such as fluororesin fiber Reinforcement, talc, calcium carbonate, mica, inorganic fillers such as glass beads, glass powder, glass balloons, fluororesin powder, solid lubricants such as graphite and molybdenum disulfide, plasticizers such as paraffin oil, antioxidants , Heat stabilizer, light stabilizer, UV absorber,
Examples include various additives such as a neutralizing agent, a lubricant, a compatibilizer, an antifogging agent, an antiblocking agent, a slip agent, a dispersant, a coloring agent, an antibacterial agent, and an optical brightening agent. In particular, when it is used for a medium holding component such as a turntable, it is desirable to strengthen it with the above-mentioned various filling reinforcing materials in order to improve the dimensional accuracy of the component and prevent resonance of the component due to rotation. The reinforcing material is 0 to 250 parts by weight (preferably 20 to 150 parts by weight) with respect to 100 parts by weight of the non-olefinic thermoplastic resin.
(Parts by weight) is preferable.

(Manufacturing Method of Holding Member) As a method for adhering the thermoplastic elastomer soft part and the metal or thermoplastic resin support, after the support is molded in advance,
A thermoplastic elastomer member may be heat-sealed to this, or conversely, a thermoplastic resin support member may be heat-sealed to a preformed thermoplastic elastomer member. As a method for producing such a composite molded article, a T die laminate molding method,
Coextrusion molding method, blow molding method, insert injection molding method,
Various molding methods such as a two-color injection molding method, a core back injection molding method, a sandwich injection molding method, and an injection press molding method can be used. Among them, insert injection molding, two-color injection molding, and core back injection molding are desirable from the viewpoint of productivity.

The insert injection molding method means, for example, that a support is previously molded by machining, forging, injection molding, extrusion molding, sheet molding, film molding, etc., and a shaped molded product is inserted into a mold, By a molding method in which a soft member (thermoplastic elastomer) is injection-molded in the space between the molded product and a mold, or by pre-molding the soft member (thermoplastic elastomer) by injection molding, extrusion molding, sheet molding, film molding, or the like. This is a molding method in which a molded product that has been molded and shaped is inserted into a mold, and then a support member (non-olefinic thermoplastic resin) is injection-molded in a space between the molded product and the mold.

The two-color injection molding method is a method in which two or more injection molding machines are used to injection-mold a support member (non-olefinic thermoplastic resin) and then the mold rotates or moves. In this molding method, the cavity of the mold is replaced and a void is formed between the molded product and the mold, and a soft member (thermoplastic elastomer) is injection-molded therein. In addition, the core back injection molding method means one injection molding machine and one
After injection-molding the support (non-olefinic thermoplastic resin) using one mold, the cavity volume of the mold is expanded, and the soft member (heat This is a molding method of injection molding a plastic elastomer).

Further, the supporting member may be molded by using an ordinary injection molding method or by gas injection molding. It is also possible to recycle the runners, spools and the like made of only the soft member to the soft member, and the support member only, or the runners, spools and defective molded products made of the support member and the soft member to the support member. .

[0058]

EXAMPLES Table 1 shows elastomers for holding members used in Examples and Comparative Examples. Details of each component are as follows. Styrene-based TPE (a): hydrogenated S-BI-S (weight average molecular weight 216,000, styrene content 30% by weight,
1,2-microstructure 8%) 34.8% by weight, paraffin oil (weight average molecular weight 746, 40 ° C. kinematic viscosity 38)
1.6 cst, fluidity -15 ° C, flash point 300 ° C, ring analysis 0%) 52.2% by weight, ethylene / propylene block copolymer (MFR 30 g / 10 minutes, flexural modulus 10,
After blending 000 kg / cm ² , 13% by weight of ethylene content, 13% by weight of crystallinity 55%, melt-kneading at 200 ° C. using a twin-screw extruder, and styrene-based TPE (JIS
-A hardness 45, MFR 1.5g / 10 minutes, specific gravity 0.9
0) was obtained.

Styrene-based TPE (b): Silicone oil (“SH200 1000cs” manufactured by Toray Dow Corning Silicone Co., Ltd.) as a blocking agent with respect to 100 parts by weight of the styrene-based TPE (a).
1.0 part by weight and 0.3 part by weight of oleic amide (“Diamid O-200” manufactured by Nippon Kasei Co., Ltd.) as a release agent and antioxidant (“Irganox 1010” manufactured by Ciba Geigy Co., Ltd.) ) 0.1 part by weight, and melt-kneaded at 200 ° C. using a twin-screw extruder to obtain styrene-based TPE (J
IS-A hardness 45, MFR 1.5g / 10 minutes, specific gravity of 0.
90) was obtained.

Styrenic TPE (c): Hydrogenated S-I-S
(Weight average molecular weight 238,000, styrene content 35
%, 1,2-microstructure 0%) 24.4% by weight,
Paraffin oil (weight average molecular weight 746, kinematic viscosity 401.6 ° C. 381.6 cst, fluidity -15 ° C., flash point 300
° C, ring analysis 0%) 36.6% by weight, ethylene / propylene block copolymer (MFR 30 g / 10 min, flexural modulus 10,000 kg / cm ² , ethylene content 8% by weight,
After blending 9% by weight of crystallinity 55%) and 30% by weight of calcium carbonate (specific surface area 11,000 cm ² / g, average particle size 3.5 μm), further blocking was performed against 100 parts by weight of these total amounts. Silicone oil (“SH2” manufactured by Toray Dow Corning Silicone Co., Ltd.) as an inhibitor
00 1000 cs ") and 0.5 part by weight of oleic acid amide (manufactured by Nippon Kasei Co., Ltd. as" Diamid O- "
200 ") and 0.2 parts by weight of an antioxidant (0.1 part by weight of" Irganox 1010 "manufactured by Ciba-Geigy Co., Ltd.) are added, and the mixture is melt-kneaded at 200 ° C using a twin-screw extruder. , Styrene-based TPE (JIS-A hardness 55, MFR
1.5 g / 10 min, specific gravity 1.1) was obtained.

Styrene-based TPE (d): Hydrogenated S-B-S
(Weight average molecular weight 246,000, styrene content 32
% By weight, 1,2-microstructure 37%) 22% by weight, paraffin oil (weight average molecular weight 746, 40 ° C. kinematic viscosity 381.6 cst, fluidity -15 ° C., flash point 300 ° C.,
Ring analysis 0%) 33% by weight, ethylene / propylene block copolymer (MFR 30 g / 10 min, flexural modulus 10,
000 kg / cm ² , ethylene content 8% by weight, crystallinity 55% 15% by weight, calcium carbonate (specific surface area 11,
000 cm ² / g, average particle size 3.5 μm) 30% by weight, and then a silicone oil (Toray Dow Corning Silicone Co., Ltd.) was added as a blocking inhibitor to 100 parts by weight of the total amount. Made "SH200
10 parts ") and 0.3 part by weight of oleic acid amide as a release agent (" DIAMID O-20 "manufactured by Nippon Kasei Co., Ltd.).
0 ") 0.1 part by weight, 0.1 part by weight of antioxidant (" Irganox 1010 "manufactured by Ciba-Geigy Co., Ltd.) and 1.0 part by weight of carbon black are added, and a twin screw extruder is used. Melted and kneaded at 200 ℃, styrene-based TPE
(JIS-A hardness 75, MFR 15 g / 10 min, specific gravity 1.1) was obtained.

70% by weight of olefinic TPE EPDM (ML _{1 + 4} (100 ° C.) 62, propylene content 28% by weight, non-conjugated diene component is 5-ethylidene norbornene, iodine value 15, oil extension amount 75 parts by weight) , Paraffin oil (weight average molecular weight 746, 40
Kinematic viscosity 381.6 cst, fluidity -15 ° C, flash point 3
(00 ° C, ring analysis 0%: the oil-extended component of the above EPDM is the same)
15% by weight, ethylene / propylene block copolymer (MFR 30 g / 10 min, flexural modulus 10,000 kg
/ Cm ² , ethylene content 8% by weight, crystallinity 55%) 1
After blending 5% by weight, 0.1 part by weight of an antioxidant (“Irganox 1010” manufactured by Ciba-Geigy Co., Ltd.) was added to 100 parts by weight of the total amount, and 170 parts by a Banbury mixer After kneading at a temperature of ° C for 6 minutes, a sheet was cut to obtain pellets. Then, L
/ D = 33, using a twin-screw extruder having a cylinder diameter of 45 mm, 100 parts by weight of the pellets were mixed with 2,5-dimethyl-2,5-di (t-butylperoxy) hexane-3 as a peroxide. 3 parts by weight, 0.4 parts by weight of divinylbenzene as a crosslinking aid, and 0.5% of silicone oil (“SH200 500cs” manufactured by Toray Dow Corning Silicone Co., Ltd.) as an antiblocking agent.
0.2 parts by weight of oleic acid amide ("Diamid O-200" manufactured by Nippon Kasei Co., Ltd.) as a release agent and 0.2 part by weight of antioxidant ("Irganox 1010" manufactured by Ciba Geigy Co., Ltd.). 1 part by weight and 1.0 part by weight of carbon black are added, and heat treatment (crosslinking treatment) is performed at a set temperature of 220 ° C. to partially crosslink olefin-based TPE (JIS-
A hardness 60, MFR 0.1g / 10 minutes, specific gravity 0.88)
I got

Ester-type TPE (a): dimethyl terephthalate 54.4 parts by weight, 1,4-butanediol 30
To 40 parts by weight of polytetramethylene ether glycol (average weight molecular weight 1,000), 200 ppm of tetrabutyl titanate as a catalyst in terms of metallic titanium is added to the produced polymer at 150 ° C. to 23 ° C.
The transesterification reaction is carried out at 0 ° C. for 3.5 hours, and then sodium hypophosphite monohydrate is added to the produced polymer in an amount of 50 ppm based on a hindered phenolic oxidation stabilizer [Ciba Geigy Co., Ltd. product, Product Name: Irganox
1010] 0.18 parts by weight was added, and melt polycondensation was performed at 230 to 245 ° C. under a reduced pressure of 3 torr or less to obtain a polyester elastomer (polyester polyether block copolymer: density 1.17 g / cm ³ , JIS-A. Hardness 97, MFR (245 ° C, 2.16kg load) 30g /
10 minutes).

Ester-type TPE (b): same as C-1 with respect to 48 parts by weight of dimethyl terephthalate, 27 parts by weight of 1,4-butanediol and 50 parts by weight of polytetramethylene ether glycol (average weight molecular weight 1,000). Polyester elastomer (polyester polyether block copolymer: density 1.15 g / cm ³ ,
JIS-A hardness 95, MFR (245 ° C, 2.16kg
Load) 35 g / 10 minutes) was obtained.

Ester-based TPE (c): same as C-1 with respect to 32 parts by weight of dimethyl terephthalate, 20 parts by weight of 1,4-butanediol, and 70 parts by weight of polytetramethylene ether glycol (average weight molecular weight 2,000). Polyester elastomer (polyester polyether block copolymer: density 1.05 g / cm ³ ,
JIS-A hardness 77, MFR (245 ° C, 2.16kg
Load) 45 g / 10 minutes) was obtained.

Amide-based TPE (a): manufactured by Toray Industries, Inc.
Pebax 5533 JIS-A hardness 97 Amide-based TPE (b): Toray Industries, Inc. Pebax 5533 JIS-A hardness 76 Urethane-based TPE: Nippon Miractolan Co., Ltd. Miractolan E198 JIS-A hardness 98 Each material is biaxially kneaded. The mixture was kneaded and granulated using an extruder, and then the pellets were molded using an in-line screw type injection molding machine at a molding temperature of 240 to 210 ° C and a mold temperature of 50 ° C.

<Examples 1 to 6 and Comparative Examples 1 to 7> Details of each evaluation method will be described below. All measurements are 2
It was performed in an environment of 5 ° C. and 50% RH. (Hardness) JIS K6301 A type (heat-bonding property) A test piece (R of 10 mm × 80 mm × 2 mm) of a supporting member made of polycarbonate resin, polyphenylene sulfide resin, or aluminum.
10 mm x 100 mm in advance (max 1.0 μm)
After using an adhesive tape to insert into a 4 mm thick die cavity, each elastomer material in Table 1 was injection molded and heat-sealed. Then, the peel strength at 90 ° between the elastomer portion and the supporting member was measured.

The materials of the support used in the above evaluation are as follows. Polycarbonate resin Novarex 7025A Polyphenylene sulfide resin manufactured by Mitsubishi Engineering-Plastics Co., Ltd. Toprene LD-10 manufactured by Topren Co., Ltd. Next, a CD-ROM turntable evaluation sample shown in FIG. 1 was obtained by the following method.

Polycarbonate resin (Novarex 7025 manufactured by Mitsubishi Engineering Plastics Co., Ltd.)
A) 70 parts by weight of glass fiber 3 surface-treated with a silane coupling agent having a fiber diameter of 10 μm and a fiber length of 6 mm
0 parts by weight were blended and melt-kneaded using a twin-screw kneading extruder. The flexural modulus of this composition according to JIS-K7203 was 69,000 kg / cm ² . Next, this was injection-molded at a molding temperature of 280 ° C. and a mold temperature of 90 ° C. to obtain the turntable support base 3 shown in FIG. Further, the molded body was inserted into a mold and the thermoplastic elastomer shown in Table 1 was injection-molded to heat-bond the soft ring 4 to the support base 3. Although a yoke, a magnet and the like are inserted in the normal turntable 1, they are omitted because they are irrelevant to the evaluation in this embodiment.

The respective dimensions of the turntable 1 were as follows. a = 30 mm b = 26 mm c = 15 mm d = 5 mm e = 3 mm f = 0.3 mm This turntable is on a soft member (receiving area 1.76c).
The CD-ROM disk is carried in m ² ) and the disk is pressed and held by the load from above. The details of the evaluation method are described below.

(Adhesiveness to disc) A CD-ROM disc 5 (made of PC resin) was placed on the soft part of the obtained turntable, and a load of 1,000 g (contact pressure 568 g / cm).
² ) was loaded, and this was left for 20 hours in a constant temperature and humidity chamber at 60 ° C. and 50%. Thereafter, the strength required for vertically removing the disk from the turntable was measured, and the sticking force was evaluated.

(Friction coefficient to disk) The test machine shown in FIG. 2 was used. That is, the outer circumference of the CD-ROM disk 5 (made of PC resin) pressed by a load 7 of 1,000 g on the fixed turntable is pulled by a load 8 in the tangential direction. The load 8 was increased in steps of 10 g, and the coefficient of static friction was obtained from the load when the disk started to move.

<Examples 7 to 8 and Comparative Examples 8 to 10> (Adhesiveness to magnetic tape) A magnetic tape was brought into contact with an injection sheet of 100 mm x 100 mm x 2 mmt made of the thermoplastic elastomer shown in Table 1 to make the contact area. 5 for 3.3 cm ² (1.26 cm x 2.6 cm)
A load of 0 g was applied, the mixture was left in an oven at 60 ° C. for 2 hours, and then the sticking property was evaluated. The magnetic tape used was the back surface of AV120 manufactured by Victor Company of Japan, Ltd. (the surface to which the magnetic surface was not applied). The criteria for the evaluation results are as follows. ○… When the sheet is tilted and shaken after removing the load, the tape falls under its own weight. × ... Even after the load is removed and the sheet is tilted and shaken, the tape sticks and does not fall off.

(Friction coefficient to magnetic tape) The measuring device shown in FIG. 3 was used. The back surface of the magnetic tape 5 is brought into contact with the thermoplastic elastomer sheet 4, and the contact area is 1 cm ² (1 cm ×
1 cm) with a load 7 of 200 g and a load 8 of 10 g
The coefficient of static friction was measured from the load that the magnetic tape 5 increased in increments and slipped off.

[0075]

[Table 1]

[0076]

[Table 2]

[0077]

[Table 3]

[0078]

[Table 4]

[0079]

[Table 5]

[0080]

INDUSTRIAL APPLICABILITY As shown in the examples, the specific thermoplastic T
A holding member formed by molding a PE composition has a high friction coefficient with respect to an information recording medium such as a PC resin information disk or a magnetic tape, but has little sticking property. Furthermore, the excellent heat-sealing property to the non-olefin resin material is effective not only for the PC resin but also for the PPS resin which is crystalline and has poor adhesiveness, and also for the aluminum. Therefore, a high-performance and inexpensive holding member for an information recording medium, which uses a non-olefin resin material or the like as a support base, can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a turntable shown as an example of an information recording medium holding member.

2A and 2B are diagrams showing static friction coefficient measurement for a CD-ROM, in which FIG. 2A is a longitudinal sectional view and FIG. 2B is a plan view.

FIG. 3 is a vertical sectional view of a friction coefficient measuring device for a magnetic tape.

[Explanation of symbols]

1 Information recording medium holding member (information disk turntable) 3 Support 4 Soft ring 5 Information recording medium 7 Load 8 Load

Claims (5)

[Claims] 1. A holding member for an information recording medium, which is obtained by molding a thermoplastic elastomer composition comprising the following component (a) and component (b). Component (a) Non-polar thermoplastic elastomer 10 to 90 parts by weight Component (b) JIS-A Thermoplastic elastomer composed of a segment having a hardness of 85 or more and a hard component containing a polar group 10 to 90 parts by weight 2. The component (a) comprises a styrene elastomer and / or an olefin elastomer.
The holding member for the information recording medium described. 3. The component (b) is an ester elastomer,
The holding member for an information recording medium according to claim 1, comprising one kind or a mixture of two or more kinds selected from the group consisting of an amide elastomer and a urethane elastomer. 4. A thermoplastic elastomer composition according to claim 1, wherein the information recording medium holding member has a flexural modulus of 15,
The holding member for an information recording medium according to claim 1, which is a turntable for an information disk obtained by heat-sealing a non-olefin of 000 kg / cm ² or more on a disc-shaped support made of a thermoplastic resin. 5. The component (b) of the thermoplastic elastomer composition comprises an ester elastomer and the support made of a thermoplastic resin comprises a polycarbonate resin.
The holding member for the information recording medium described.