JP2007297440A - Method of producing thermoplastic elastomer composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a thermoplastic elastomer composition difficult to give rise to molding defect and excellent in moldability. <P>SOLUTION: The method of producing the thermoplastic elastomer composition difficult to give rise to molding defect and excellent in moldability comprises melt-kneading a cross-linking constituent and a cross-linking agent under the existence of a thermoplastic resin to cross-link dynamically the cross-linking constituent by the cross-linking agent using a twin screw extruder wherein the total shearing strain ε is not less than 8,000 and not greater than 20,000 when kneading in the twin screw extruder. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a thermoplastic elastomer composition which is rich in flexibility and excellent in moldability, rubber-like properties, compression set properties, gas barrier properties and vibration damping properties.

  Conventionally, as a polymer material having elasticity, a material obtained by blending a rubber such as natural rubber or synthetic rubber with a crosslinking agent or a reinforcing agent is used. However, such rubbers require a process of crosslinking and molding for a long time under high temperature and pressure, and are inferior in processability. In addition, since the crosslinked rubber does not exhibit thermoplasticity, it is usually not possible to perform recycle molding like a thermoplastic resin. For this reason, various thermoplastic elastomers have been developed in recent years that can be easily manufactured using general-purpose melt molding techniques such as hot press molding, injection molding, and extrusion molding in the same way as ordinary thermoplastic resins. Yes. As such thermoplastic elastomers, various types of polymers such as olefin-based, urethane-based, ester-based, styrene-based, and vinyl chloride-based are currently developed and marketed.

  Such thermoplastic elastomers can be divided into a crosslinked type and a non-crosslinked type.

  Non-crosslinked thermoplastic elastomers do not involve a crosslinking reaction, so there is little variation in quality, and the manufacturing cost is low. On the other hand, when comparing the two from the viewpoint of performance, in terms of tensile strength, elongation at break, rubber-like properties (for example, permanent elongation, compression set) and heat resistance, it is cross-linked compared to non-crosslinked thermoplastic elastomers. The thermoplastic elastomer is superior.

  Examples of the cross-linked thermoplastic elastomer include a rubber-like composition comprising a styrene elastomer and an unsaturated double bond-containing rubber containing a cross-linking agent having a SiH group (Patent Document 1). These cross-linked thermoplastic elastomers may be sufficiently cross-linked as judged from the gel fraction, but depending on the production conditions, there may be residual unreacted cross-linking agent in the case of molding after pelletizing once. It may cause molding defects.

JP-A-8-27319

  In the present invention, it is an object to provide a method for producing a thermoplastic elastomer composition excellent in moldability that hardly causes molding defects.

  As a result of intensive investigations in view of the above problems, the present inventors have used a twin screw extruder to dynamically crosslink a component to be cross-linked with a cross-linking agent in the presence of a thermoplastic resin to produce a thermoplastic elastomer composition. The present inventors have found that the above problem can be solved by setting the total shear strain amount ε in the twin-screw extruder to a predetermined range, and have reached the present invention.

  That is, the present invention relates to a thermoplastic elastomer in which a crosslinkable component is dynamically cross-linked by a crosslinker by melt-kneading the crosslinkable component and a crosslinker in the presence of a thermoplastic resin using a twin screw extruder. In the method for producing a composition, the present invention relates to a method for producing a thermoplastic elastomer composition, characterized in that a total shear strain amount ε in a twin-screw extruder during kneading is 8000 or more and 20000 or less.

  According to the method of the present invention, it is possible to easily obtain a thermoplastic elastomer composition that hardly causes defective molding.

  In the method for producing the thermoplastic elastomer composition according to the present invention, the crosslinkable component and the crosslinking agent are melt-kneaded in the presence of the thermoplastic resin using a twin-screw extruder, so that the crosslinkable component is mixed with the crosslinking agent. When producing a thermoplastic elastomer composition by dynamically crosslinking, the total shear strain amount ε in the twin-screw extruder during kneading is set to 8000 or more and 20000 or less.

  In addition, the total shear strain amount ε in the twin-screw extruder can be obtained from the following formula.

（式中、πは円周率、Ｄは押出機の口径（ｍｍ）、Ｎはスクリュー回転数（ｒｐｍ）、ｔは滞留時間（秒）、ｈはスクリュー溝深さ（ｍｍ）である。）

(In the formula, π is the circumferential ratio, D is the diameter of the extruder (mm), N is the screw rotation speed (rpm), t is the residence time (seconds), and h is the screw groove depth (mm).)

  The components contained in the thermoplastic elastomer composition produced by the production method of the present invention include a thermoplastic resin, a cross-linked component, and a crosslinking agent. Furthermore, a crosslinking catalyst, a plasticizer, a filler and the like are included as necessary.

  The thermoplastic resin is not particularly limited, and for example, at least one selected from the group consisting of plastics, rubbers, and thermoplastic elastomers can be used. Examples of the plastics include olefin resins such as polypropylene and polyethylene, polystyrene, ABS, MBS, acrylic, polyurethane, polyvinyl chloride, polyester, polyamide, and the like.

  Examples of rubbers include polyether, polybutadiene, natural rubber, butyl rubber, chloroprene rubber, and ethylene-propylene rubber.

  Examples of the thermoplastic elastomer include styrene elastomer (aromatic vinyl thermoplastic elastomer) which is a block copolymer composed of a polystyrene block or the like and a polybutadiene or polyisoprene block, a polyolefin component such as polypropylene, and ethylene-propylene. Olefin elastomers composed of rubber components such as rubber, vinyl chloride elastomers composed of crystalline and non-crystalline polyvinyl chloride, urethane elastomers that are block copolymers composed of polyurethane blocks and polyether blocks, polyester blocks and poly Polyester elastomers that are block copolymers composed of ether blocks, etc., and amide elastomers that are block copolymers composed of polyamide blocks and polyether blocks Ma and the like.

  These thermoplastic resins can be used alone or in combination of two or more, regardless of the classification of plastics, rubbers, and thermoplastic elastomers.

  Of the above thermoplastic resins, olefin resins such as polypropylene and polyethylene, and aromatic vinyl thermoplastic elastomers are preferred in terms of processability, flexibility, and strength. Further, polyethylene having a good compression set is preferable as the olefin resin, and the polymer block and isobutylene polymer block mainly composed of an aromatic vinyl compound having excellent gas barrier properties are used as the aromatic vinyl thermoplastic elastomer. A block copolymer consisting of

  Examples of the aromatic vinyl compound in the polymer mainly composed of the aromatic vinyl compound include styrene, α-methylstyrene, β-methylstyrene, p-methylstyrene, t-butylstyrene, monochlorostyrene, dichlorostyrene, methoxy Examples thereof include styrene, indene, divinylbenzene, N, N-dimethyl-p-aminoethylstyrene, N, N-diethyl-p-aminoethylstyrene, vinylpyridine, and the like. Among the above compounds, styrene, α-methylstyrene, p-methylstyrene, and indene are preferable from the balance of cost, physical properties, and productivity. Two or more of these may be selected and used.

  The structure of the block copolymer is not particularly limited, but AB type or ABA type is preferable. Examples of the aromatic vinyl-based thermoplastic elastomer include a block copolymer composed of a block having an aromatic vinyl-based compound as a constituent monomer and a butadiene and / or isoprene block, and a hydrogenated product thereof. For example, SBS (styrene-butadiene-styrene block copolymer), SIS (styrene-isoprene-styrene block copolymer), SEBS (styrene-ethylenebutylene-styrene block copolymer), SEPS (styrene-ethylenepropylene-styrene). Block copolymer) and styrene-isobutylene-styrene block copolymer (SIBS).

  The ratio of the polymer mainly composed of the aromatic vinyl compound is not particularly limited, but from the balance between physical properties and processability, the soft segment such as an isobutylene polymer block is 95 to 20% by weight, the aromatic vinyl compound is The main polymer block is preferably 5 to 80% by weight, the isobutylene polymer block is 90 to 60% by weight, and the polymer block mainly composed of an aromatic vinyl compound is 10 to 40% by weight. Is particularly preferred.

  The number average molecular weight of the aromatic vinyl-based thermoplastic elastomer is not particularly limited, but is preferably 15,000 to 500,000, particularly preferably 40,000 to 400,000. When the number average molecular weight is less than 15,000, the mechanical properties and the like are not sufficiently expressed, and when it exceeds 500,000, the moldability and the like are greatly deteriorated.

  In the present invention, the cross-linked component is a component that is dynamically cross-linked by reacting with a cross-linking agent. The cross-linked component is preferably 20% by weight or more and 50% by weight or less in the thermoplastic elastomer composition. This is because if it is less than 20% by weight, the compression set obtained by dynamic crosslinking is not sufficiently improved, and if it is more than 50% by weight, the fluidity of the thermoplastic elastomer composition obtained by dynamic crosslinking is deteriorated, and injection molding is performed. This is because a process of blending with a material having good fluidity in advance is required. The weight% concentration of the cross-linked component can be determined, for example, by measuring the weight of an insoluble component obtained by dissolving a thermoplastic elastomer in hot xylene.

  Examples of the cross-linked component include an isobutylene polymer having an unsaturated bond, an ethylene / α-olefin copolymer rubber, an isoprene rubber, and a butadiene rubber.

  The isobutylene polymer having an unsaturated bond is a polymer mainly composed of isobutylene and means a polymer having an unsaturated bond as shown below. The monomer other than isobutylene in the isobutylene polymer is not particularly limited as long as it is a monomer component capable of cationic polymerization, but dienes such as aromatic vinyls, aliphatic olefins, isoprene, butadiene, and divinylbenzene. And monomers such as vinyl ethers and β-pinene. These may be used alone or in combination of two or more.

  The number average molecular weight of the isobutylene polymer is not particularly limited, but is preferably 1,000 to 500,000, particularly preferably 5,000 to 200,000. When the number average molecular weight is less than 1,000, mechanical properties and the like are not sufficiently exhibited, and when it exceeds 500,000, the moldability and the like are greatly deteriorated.

  The unsaturated bond in the present invention is not particularly limited as long as it is a carbon-carbon double bond that is active for the crosslinking reaction of the components for achieving the object of the present invention. Specific examples include aliphatic unsaturated hydrocarbon groups such as vinyl group, allyl group, methyl vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group. And cyclic unsaturated hydrocarbon groups such as

  As a method for introducing an unsaturated bond of an isobutylene polymer, an unsaturated group is added to a polymer having a functional group such as a hydroxyl group as disclosed in JP-A-3-152164 and JP-A-7-304909. The method which introduce | transduces an unsaturated group into a polymer by making the compound which has it react is mentioned. In order to introduce an unsaturated group into a polymer having a halogen atom, a method of performing a Friedel-Crafts reaction with alkenylphenyl ether, a method of performing a substitution reaction with allyltrimethylsilane in the presence of a Lewis acid, various phenols, etc. And a method of performing the above-mentioned alkenyl group introduction reaction after introducing a hydroxyl group by performing a Friedel-Crafts reaction. Further, as disclosed in US Pat. No. 4,316,973, Japanese Patent Application Laid-Open No. 63-105005, and Japanese Patent Application Laid-Open No. 4-288309, an unsaturated group can be introduced during the polymerization of the monomer. Among these, those in which an allyl group is introduced at the terminal by a substitution reaction of allyltrimethylsilane and chlorine are preferable from the viewpoint of certainty of the reaction. However, the method of introduction and the position of introduction of the unsaturated bond are not particularly questioned.

  The amount of the unsaturated bond of the isobutylene polymer can be arbitrarily selected depending on the required properties, but from the viewpoint of the properties after crosslinking, a polymer having at least 0.2 alkenyl groups per molecule at the terminal It is preferable that If the number is less than 0.2, there may be a case where the effect of improving properties due to crosslinking cannot be sufficiently obtained.

  The means for crosslinking the isobutylene-based polymer having an unsaturated bond is not particularly limited, but a hydrosilyl group-containing compound is used as a crosslinking agent because of the advantage that no by-product is generated and unnecessary side reaction does not occur. It is preferable to crosslink.

There is no restriction | limiting in particular in the hydrosilyl group containing compound used as a crosslinking agent, Various things can be used. That is, a linear polysiloxane represented by the general formula (I) or (II);
_{^{R 1 3 SiO- [Si (R}} 1) 2 O] a - [Si (H) (R 2) O] b - [Si (R 2) (R 3) O] c -SiR 1 3 (I)
_{^{HR 1 2 SiO- [Si (R}} 1) 2 O] a - [Si (H) (R 2) O] b - [Si (R 2) (R 3) O] c -SiR 1 2 H (II)
(Wherein R ¹ and R ² represent an alkyl group having 1 to 6 carbon atoms or a phenyl group, R ³ represents an alkyl group having 1 to 10 carbon atoms or an aralkyl group. A represents 0 ≦ a ≦ 100, b Represents an integer satisfying 2 ≦ b ≦ 100 and c satisfying 0 ≦ c ≦ 100.)
A cyclic siloxane represented by the general formula (III);

（式中、Ｒ⁴およびＲ⁵は炭素数１〜６のアルキル基、または、フェニル基、Ｒ⁶は炭素数１〜１０のアルキル基またはアラルキル基を示す。ｄは０≦ｄ≦８、ｅは２≦ｅ≦１０、ｆは０≦ｆ≦８の整数を表し、かつ３≦ｄ＋ｅ＋ｆ≦１０を満たす。）等の化合物を用いることができる。さらに上記のヒドロシリル基（Ｓｉ−Ｈ基）を有する化合物のうち、相溶性が良いという点から、特に下記の一般式（ＩＶ）で表されるものが好ましい。

(In the formula, R ⁴ and R ⁵ represent an alkyl group having 1 to 6 carbon atoms or a phenyl group, R ⁶ represents an alkyl group having 1 to 10 carbon atoms or an aralkyl group. D represents 0 ≦ d ≦ 8, e 2 ≦ e ≦ 10, f represents an integer of 0 ≦ f ≦ 8, and 3 ≦ d + e + f ≦ 10 is satisfied). Furthermore, among the compounds having the above hydrosilyl group (Si—H group), those represented by the following general formula (IV) are particularly preferable from the viewpoint of good compatibility.

（式中、ｇ、ｈは整数であり２≦ｇ+ｈ≦５０、２≦ｇ、０≦ｈである。Ｒ⁷は水素原子またはメチル基を表し、Ｒ⁸は炭素数２〜２０の炭化水素基で１つ以上の芳香環を有していても良い。ｉは０≦ｉ≦５の整数である。）

(In the formula, g and h are integers, and 2 ≦ g + h ≦ 50, 2 ≦ g, and 0 ≦ h. R ⁷ represents a hydrogen atom or a methyl group, and R ⁸ represents carbonization having 2 to 20 carbon atoms. (It may be a hydrogen group and may have one or more aromatic rings. I is an integer of 0 ≦ i ≦ 5.)

  When a hydrosilyl group-containing compound is used as a crosslinking agent, the isobutylene polymer having an unsaturated bond and the hydrosilyl group-containing compound can be mixed at an arbitrary ratio, but from the viewpoint of crosslinkability, the unsaturated bond and the hydrosilyl group are mixed. The molar ratio (number of moles of unsaturated bond / number of moles of hydrosilyl group) is preferably in the range of 5 to 0.05, more preferably 2.5 to 0.1. When the molar ratio is 5 or more, only a crosslinked product with insufficient strength due to insufficient curing can be obtained, and when it is less than 0.05, a large amount of active hydrosilyl groups remain in the crosslinked product even after crosslinking. Therefore, cracks and voids are generated, and a uniform and strong crosslinked product cannot be obtained.

  The thermoplastic elastomer composition may contain a crosslinking catalyst. The crosslinking catalyst is not particularly limited, and examples thereof include radical initiators such as organic peroxides and azo compounds, and transition metal catalysts.

  The radical initiator to be used is not particularly limited, and examples thereof include di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5- Dialkyl peroxides such as di (t-butylperoxy) -3-hexyne, dicumyl peroxide, t-butylcumyl peroxide, α, α'-bis (t-butylperoxy) isopropylbenzene, benzoyl peroxide, p-chlorobenzoyl Peroxides, m-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diacyl peroxides such as lauroyl peroxide, peracid esters such as t-butyl perbenzoate, diisopropyl percarbonate, di-2-percarbonate Peroxydicarbonates such as ethylhexyl 1,1-di (t-butylperoxy) cyclohexane, peroxyketals such as 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, and the like.

Also, the transition metal catalyst used is not particularly limited. For example, a platinum solid, alumina, silica, carbon black or the like dispersed in a platinum solid, chloroplatinic acid, chloroplatinic acid and alcohol, aldehyde, ketone And the like, platinum-olefin complexes, and platinum (0) -dialkenyltetramethyldisiloxane complexes. Examples of the catalyst other than platinum _{compounds, RhCl (PPh 3) 3,} RhCl 3, RuCl 3, IrCl 3, FeCl 3, AlCl 3, PdCl 2 · H 2 O, NiCl 2, TiCl 4 , and the like. These catalysts may be used alone or in combination of two or more. The amount of the catalyst is not particularly limited, but it is preferably used in the range of 10 ⁻¹ to 10 ⁻⁸ mol, preferably in the range of 10 ⁻³ to 10 ⁻⁶ mol, relative to 1 mol of the alkenyl group of the component. Good. If it is less than 10 ⁻⁸ mol, curing does not proceed sufficiently. Further, since the hydrosilylation catalyst is expensive, it is preferable not to use 10 ⁻¹ mol or more. Of these, platinum vinyl siloxane is most preferred in terms of compatibility, crosslinking efficiency, and scorch stability.

  When a transition metal catalyst is used as the crosslinking catalyst, it is preferable to further dilute the transition metal catalyst with an organic solvent. This is because when the transition metal catalyst is kneaded alone with the isobutylene polymer and the thermoplastic resin, the resin burns and the resulting composition turns brown. In order to suppress this discoloration, the crosslinking catalyst is preferably diluted to 5% by weight or less with an organic solvent.

  The organic solvent is not particularly limited, but examples thereof include aliphatic hydrocarbons such as hexane, heptane, and isooctane, aromatic hydrocarbons such as benzene, toluene, and xylene, acetone, ethanol, butanol, butyl chloride, and pyridine. And the like, and these may be used alone or in combination of two or more. In addition, when the organic solvent remains in the thermoplastic elastomer composition obtained, it is preferable to use an organic solvent having a boiling point of 160 ° C. or less because a problem such as bleeding of the organic solvent occurs in the product. Toluene and xylene, which do not volatilize immediately at the time of melt kneading and hardly remain at the time of cross-linking kneading, and xylene are preferable.

  A plasticizer may be used in the composition produced according to the present invention. The type of plasticizer is not particularly limited, and examples thereof include mineral oil used in rubber processing, or liquid or low molecular weight synthetic softeners, and these may be used alone or in combination of two or more. it can.

  Mineral oils include paraffinic oils, naphthenic oils, and aromatic high boiling petroleum components.

  The liquid or low molecular weight synthetic softening agent is not particularly limited, and examples thereof include polybutene, hydrogenated polybutene, liquid polybutadiene, hydrogenated liquid polybutadiene, and poly α-olefins. One or more of these plasticizers can be used. Of these, paraffinic oil and / or polybutene that does not inhibit the crosslinking reaction are preferred.

  The amount of the plasticizer is preferably 10 to 300 parts by weight with respect to 100 parts by weight of the isobutylene polymer having an unsaturated bond. If the blending amount exceeds 300 parts by weight, there may be a problem in mechanical strength reduction and moldability.

  In addition, the composition of the present invention further includes a reinforcing agent, a filler, a hindered phenol-based or hindered amine-based antioxidant, or an ultraviolet absorber within a range that does not impair the physical properties, depending on the required properties according to each application. , Light stabilizers, pigments, surfactants, flame retardants, antibacterial agents, lubricants, silicone oils, and the like can be appropriately blended.

  In the present invention, a twin screw extruder is used when kneading the above components. The twin-screw extruder includes various twin-screw extruders such as a non-meshing type same direction rotation, a meshing type same direction rotation, a non-meshing type different direction rotation, and a meshing type different direction rotation twin screw extruder. Among the twin screw extruders, a twin screw extruder of the meshing type and the same direction is preferable because it has a self-cleaning property and can increase the screw rotation speed.

  The length (L / D) with respect to the barrel diameter of the twin-screw extruder is preferably 30 to 100, more preferably 35 to 75. If L / D is less than 30, the discharge rate must be reduced in order to perform the crosslinking reaction sufficiently, resulting in poor production efficiency. If L / D is greater than 100, the resin temperature may be too high, or the motor load may be excessive.

  The set temperature of the twin screw extruder when kneading is preferably 130 to 300 ° C, more preferably 130 to 240 ° C. If the temperature is lower than 130 ° C., the thermoplastic resin may not be sufficiently melted and kneading may be uneven. If the temperature is higher than 300 ° C., thermal decomposition of the isobutylene polymer having an unsaturated bond may occur.

  In addition, the total shear strain amount ε of the twin-screw extruder when dynamically performing the crosslinking is 8000 or more and 20000 or less. If the total amount of shear strain ε is less than 8000, there is a risk that molding failure or deterioration of physical properties may be caused by insufficient reaction. On the other hand, if it is larger than 20000, excessive shearing force or heat is applied to the material, so that the production efficiency may be deteriorated or the physical properties may be deteriorated due to decomposition of the resin.

  When kneading each of the above components, the isobutylene polymer is fed to the gear pump by a method of plasticizing with a heating tank or the like, or by a method of biting into a conical feeder or the like at around room temperature, and quantitatively biaxial extrusion with the gear pump Can be put into the machine. Thermoplastic resins, reinforcing agents added as necessary, fillers, hindered phenol and hindered amine antioxidants, UV absorbers, light stabilizers, pigments, surfactants, flame retardants, antibacterial agents, lubricants Silicon oil or the like is introduced, for example, from a hopper into a twin-screw extruder using a constant-weight feeder or from a side feeder into a twin-screw extruder. The cross-linking agent, the cross-linking catalyst, and the plasticizer can be charged into the twin-screw extruder using, for example, a liquid addition pump. The order of addition is not particularly limited, but it is preferable that the thermoplastic resin and the isobutylene polymer are charged from different addition ports, and the crosslinking agent and the catalyst are charged from different addition ports. Furthermore, the method of adding the thermoplastic resin first and adding the catalyst last is most preferable because the thermoplastic resin can be easily melted and the crosslinking reaction can be easily made uniform.

  The thermoplastic elastomer composition obtained by the production method of the present invention can be molded using a molding method and a molding apparatus generally adopted for a thermoplastic resin composition, such as extrusion molding, injection molding, press molding, It can be melt molded by blow molding or the like.

  Since the thermoplastic elastomer composition obtained by the production method of the present invention is excellent in moldability and compression set characteristics, it is a sealing material such as a packing material, a sealing material, a gasket and a plug, a CD damper, and a building damper. Damping materials such as damping materials for automobiles, vehicles and home appliances, anti-vibration materials, automotive interior materials, cushion materials, daily necessities, electrical parts, electronic parts, sports materials, grips or cushioning materials, wire covering materials, packaging materials It can be used effectively as various containers and stationery parts.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by these. Prior to the examples, various measurement methods and raw material components used in the examples will be described.

(Compression set) In accordance with JIS K 6262, a 12.5 mm thick press sheet was used as a test piece. Measured at 100 ° C. × 22 hours under conditions of 25% deformation.

(Hardness) In accordance with JIS K 6252, a 12.0 mm pressure press sheet was used as a test piece.

(Maximum tensile strength) In accordance with JIS K 6251, the test piece was a 2 mm thick press sheet punched into a No. 3 shape with a dumbbell. The tensile speed was 500 mm / min.

(Tensile elongation at break) In accordance with JIS K 6251, a 2 mm thick press sheet was used as a test piece punched out into a No. 3 shape with a dumbbell. The tensile speed was 500 mm / min.

(Formability) Laboplast mill (manufactured by Toyo Seiki Co., Ltd.) set at 170 ° C. was melt-kneaded for 1 minute, and the molten thermoplastic elastomer composition was immediately heated at 190 ° C. by Kondo Metal Industries Co., Ltd. with a pressure press Press molded. The surface of the molded body was visually observed. If it was good, it was evaluated as “good”, cracks were observed, or “tack” was recognized as “poor”.

(Contents of raw material components described in Examples etc.)
Abbreviations and specific contents of materials used in Examples and Comparative Examples are as follows.
PE: high density polyethylene, manufactured by Mitsui Chemicals (trade name “HI-ZEX2200J”)
APIB: Polyisobutylene having an allyl group at the terminal (described in Production Examples)
Plasticizer: Paraffinic process oil, manufactured by Idemitsu Kosan Co., Ltd. (trade name “PW380”)
Cross-linking agent (hydrosilyl group-containing compound): Siloxane, manufactured by GE Toshiba Silicone (trade name “TSF-484”)
Cross-linking catalyst: a mixture of 0,1,3,3-tetramethyl-1,3-dialkenyldisiloxane complex of 0-valent platinum in a 3 wt% xylene solution and a plasticizer in a weight ratio of 1: 400

(Production Example) [Production of polyisobutylene having an allyl group at the terminal (APIB)]
After the inside of the polymerization vessel of the 2 L separable flask was purged with nitrogen, 142 mL of ethylcyclohexane (dried with molecular sieves) and 427 mL of toluene (dried with molecular sieves) were added using a syringe, and the polymerization vessel was -70. After cooling in a dry ice / methanol bath at ℃, a Teflon (registered trademark) feeding tube was connected to a pressure-resistant glass liquefied collection tube with a three-way cock containing 277 mL (2934 mmol) of isobutylene monomer, and a polymerization vessel Inside, isobutylene monomer was fed by nitrogen pressure. 0.85 g (3.7 mmol) of p-dicumyl chloride and 0.68 g (7.4 mmol) of α-picoline were added. Next, 5.8 mL (52.7 mmol) of titanium tetrachloride was further added to initiate polymerization. After stirring for 2.5 hours from the start of polymerization, about 1 mL of the polymerization solution was extracted from the polymerization solution for sampling. Subsequently, 1.68 g (11 mmol) of a 75% toluene solution of allyltrimethylsilane was added to the polymerization vessel. Two hours after the addition of the mixed solution, the reaction was terminated by adding a large amount of water.

  The reaction solution was washed twice with water, the solvent was evaporated, and the resulting polymer was vacuum-dried at 60 ° C. for 24 hours to obtain the desired block copolymer. The molecular weight of the polymer obtained by the gel permeation chromatography (GPC) method was measured. A polyisobutylene having an allyl group at the terminal having Mn of 45500 and Mw / Mn of 1.10 was obtained. The number of terminal allyl groups calculated from NMR was 2.0 per molecule.

(Examples 1-2)
A meshing type co-rotating twin screw extruder (Kobe Steel Ltd., screw diameter 46 mm, L / D = 63) having the configuration as shown in FIG. 1 was used. The kneading state will be described in detail. First, polyethylene is supplied to the hopper 2 of the twin-screw extruder 1 and a screw (not shown) in the twin-screw extruder 1 is rotated to be heated to a predetermined temperature. In addition, polyethylene was quantitatively introduced into the extruder 1. The twin-screw extruder 1 has addition ports 4 to 8 arranged at predetermined intervals, and APIB, a filler, a plasticizer, a crosslinking agent, and a crosslinking catalyst are sequentially supplied from these addition ports to obtain a resin. APIB and the crosslinking agent were dynamically cross-linked while melt kneading. This kneaded product was extruded from the die 3, thereby obtaining a pellet-shaped resin composition. Extrusion conditions / addition composition / addition amounts were as shown in Table 1. The obtained thermoplastic elastomer composition was molded into a sheet shape with a pressure press manufactured by Shindo Metal Industry Co., Ltd. at 190 ° C., and the hardness, compression set, and tensile properties of the obtained sheet were measured according to the above methods. The results are shown in Table 2.

(Comparative Examples 1-2)
In the same manner as in Examples 1 and 2, extrusion was performed using the extruder having the configuration shown in FIG. 1 under the extrusion conditions / addition configuration / addition amount shown in Table 1, and pelletized. The obtained thermoplastic elastomer composition was manufactured at 190 ° C. by Shinfuji Metal Industry Co., Ltd., formed into a sheet shape with a pressure press, and the hardness, compression set, and tensile properties of the obtained sheet were measured according to the above methods. Is shown in Table 2.

  From Table 1 and Table 2, the thermoplastic elastomer composition obtained by the production method of the present invention is superior in tensile properties and compression set to Comparative Example 1 of the total shear strain amount from the present invention, It can be seen that moldability is not caused and moldability is excellent. In the examples, APIB, a filler, a plasticizer, a cross-linking agent, and a cross-linking catalyst were sequentially added to polyethylene. However, the order of addition is not particularly limited in the present invention.

  As described above, according to the production method of the present invention, a thermoplastic elastomer composition having excellent tensile characteristics and compression set and excellent moldability can be obtained.

Schematic diagram of the additive configuration of the twin screw extruder

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Twin screw extruder 2 ... Hopper 3 ... Dies 4 ... APIB addition port 5 ... Filler addition port 6 ... Plasticizer addition port 7 ... Crosslinking agent addition port 8 ... Crosslinking catalyst addition port

Claims (4)

  A method for producing a thermoplastic elastomer composition by dynamically cross-linking a cross-linked component with a cross-linking agent by melt-kneading the cross-linked component and a cross-linking agent in the presence of a thermoplastic resin using a twin screw extruder The method for producing a thermoplastic elastomer composition according to claim 1, wherein the total shear strain ε in the twin-screw extruder during kneading is 8000 or more and 20000 or less.   The method for producing a thermoplastic elastomer composition according to claim 1, wherein the crosslinking agent is a hydrosilyl group-containing compound.   The method for producing a thermoplastic elastomer composition according to claim 1 or 2, wherein the cross-linked component is an isobutylene polymer having an unsaturated bond. The method for producing a thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the cross-linked component is 20% by weight or more and 50% by weight or less.

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