JP6625800B2 - Thermoplastic elastomer resin composition - Google Patents

Description

The present invention relates to a thermoplastic elastomer resin composition. More specifically, it has excellent gas barrier properties, flexibility, mechanical strength, and resistance to compression deformation in high-temperature environments, has good moldability, and can be suitably used as a material for medical or food equipment. The present invention relates to a thermoplastic elastomer resin composition.

Conventionally, as materials for medical and food equipment, particularly materials for medical syringe gaskets, and stoppers for chemical storage bottles and food storage bottles, there are gas barrier properties, compression deformation resistance, and heat resistance. Because properties are important, crosslinked rubbers such as natural rubber, butyl rubber, isoprene rubber, and styrene-butadiene rubber have been frequently used. However, the crosslinked rubber has a problem that a large-scale crosslinking step and apparatus are required, and a problem that a crosslinking agent is eluted. In addition, there is a problem that the resistance to compression deformation in a high-temperature environment is insufficient to apply the steam sterilization treatment.

For this reason, thermoplastic elastomer resins and their resin compositions have attracted attention as materials for medical and food devices. As the thermoplastic elastomer resin, various thermoplastic elastomer resins such as a polyolefin resin, a polyurethane resin, a polyester resin, a polyamide resin, a polystyrene resin, and a polyvinyl chloride resin have been proposed. Among these, in the field of medical and food appliances, polyolefin-based thermoplastic elastomer resins have received particular attention from the viewpoints of resistance to compression deformation in high-temperature environments, heat resistance, and cost. However, the polyolefin-based thermoplastic elastomer resin has a problem that a plasticizer such as a softener for rubber compounded to impart flexibility tends to bleed out.

Patent Document 1 discloses a thermoplastic elastomer (SIBS: A component in which a polymer component (S) mainly composed of styrene and a polymer component (IB) mainly composed of isobutylene are bonded in the form of S-IB-S. ), A polybutene (component (B)) and an ultrahigh molecular weight polyethylene powder (component (C)), wherein at least the thermoplastic elastomer (component (A)) is dynamically crosslinked. . "Has been proposed. However, this technique has a problem that the appearance of the obtained product, particularly the surface smoothness, is insufficient, and when applied to a syringe gasket or a bottle stopper containing a chemical solution or the like, liquid leakage easily occurs. Further, the compression deformation resistance and the heat resistance under a high temperature environment are insufficient.

Patent Document 2 proposes “a thermoplastic medical / medical seal article formed of a rubber material made of a block copolymer of an aromatic vinyl compound and isobutylene”. This technique is superior to a crosslinked rubber in that injection molding is easy, a desired molded product can be obtained, and elution resistance is good. However, the compression deformation resistance under a high temperature environment and the compression deformation resistance at room temperature are insufficient. In addition, there is a problem that a chemical reaction occurs with the above-mentioned article depending on the kind of the chemical solution as the contents.

Patent Document 3 discloses that “(A) 100 parts by weight of an isobutylene-based polymer having an alkenyl group at the terminal is melt-kneaded with (C) a hydrosilyl group-containing compound in the presence of 10 to 100 parts by weight of a polyolefin (B). And (D) a composition for a cap liner, comprising 0.1 to 20 parts by weight of a lubricant. " However, tests performed by the inventor have revealed that this technique has insufficient properties in a high-temperature environment such as resistance to compression strain in a high-temperature environment and sealing properties in a high-temperature environment.

Patent Document 4 discloses that “(a) 100 parts by mass of an isobutylene-based polymer having an alkenyl group at a terminal is obtained by adding (b) 5 to 100 parts by mass of a polyolefin and (c) 5 to 100 parts by mass of polybutene, d) A pharmaceutical / medical rubber compound comprising a composition (component A) obtained by crosslinking during melt-kneading with a hydrosilyl group-containing compound and an ultra-high molecular weight polyethylene powder (component B). " Has been proposed. However, tests performed by the inventor have revealed that this technique has insufficient properties in a high-temperature environment, such as resistance to compression strain in a high-temperature environment and sealing properties in a high-temperature environment.

JP 2008-228915 A JP-A-5-212104 International Publication No. WO 2006/098142 International Publication No. 2009/013945

An object of the present invention is to provide high gas barrier properties required for medical and food equipment, particularly materials for medical syringe gaskets, and materials for stoppers for medical solution storage bottles and food storage bottles, and resistance to compression deformation in high temperature environments. An object of the present invention is to provide a thermoplastic elastomer resin composition which has properties, flexibility, and mechanical strength, has good moldability and can improve productivity.

As a result of intensive studies, the present inventor has found that the above object can be achieved by a specific thermoplastic elastomer resin composition.

That is, the present invention provides (a) 20 to 80% by mass of a crosslinked elastic body having a structural unit derived from isobutylene;
(B) A hydrogenated product of a block copolymer of an aromatic vinyl compound and a conjugated diene compound (b1), and a block copolymer of an aromatic vinyl compound and isobutylene (b2)
At least one selected from the group consisting of 80 to 20% by mass,
Here, the total of the components (a) and (b) is 100% by mass, 100 parts by mass of the resin composition; and (c) 5 to 50 parts by mass of a polyolefin-based resin;
It is a thermoplastic elastomer resin composition containing:

The second invention is the thermoplastic elastomer resin composition according to the first invention, wherein the component (a) is a crosslinked elastic body obtained by crosslinking using a hydrosilyl group-containing compound.

In a third aspect, the component (b) is a styrene-ethylene-butene block copolymer (SEB), a styrene-ethylene-propylene block copolymer (SEP), or a styrene-ethylene-butene-styrene block copolymer. (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-isobutylene-styrene block copolymer (SIBS), and The thermoplastic elastomer resin composition according to the first or second invention, which is at least one selected from the group consisting of styrene-vinyl (ethylene-propylene) -styrene copolymer (V-SEPS). .

A fourth invention is a thermoplastic elastomer resin according to any one of the first to third inventions, wherein the component (c) is at least one selected from the group consisting of a polypropylene resin and a polyethylene resin. A composition.

The fifth invention further comprises (d) a rubber softener in an amount of 5 to 100 parts by mass based on 100 parts by mass of the resin composition comprising the component (a) and the component (b). The thermoplastic elastomer resin composition according to any one of the above-described inventions.

A sixth invention is a medical device including the thermoplastic elastomer resin composition according to any one of the first to fifth inventions.

A seventh invention is a food appliance comprising the thermoplastic elastomer resin composition according to any one of the first to fifth inventions.

The thermoplastic elastomer resin composition of the present invention is excellent in gas barrier properties, resistance to compression deformation in a high-temperature environment, flexibility, and mechanical strength, and has good moldability. Therefore, using the thermoplastic elastomer resin composition of the present invention as a material, a medical or food device, particularly a medical syringe gasket, and a stopper for a medicine storage bottle or a food storage bottle can be obtained with high productivity.

(A) a crosslinked elastic body having a structural unit derived from isobutylene:
The above component (a) is composed of isobutylene (CH ₂ ＣC (CH ₃ ) ₂ ), a small amount of isoprene (CH ₂ ＣC (CH ₃ ) —CH こ れ ら CH ₂ ), and any monomer capable of cationic polymerization with these. A rubber (elastic body) obtained by crosslinking a copolymer obtained by cationic polymerization at a low temperature.

The content of the structural unit derived from isobutylene of the component (a) is usually 70 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more from the viewpoint of gas barrier properties and heat resistance. On the other hand, from the viewpoint of crosslinkability, it is usually at most 99.5 mol%, preferably at most 99 mol%.

The content of the structural unit derived from isoprene of the component (a) is usually 5 mol% or less, preferably 2.5 mol% or less from the viewpoint of heat resistance. On the other hand, from the viewpoint of crosslinking properties, it is usually at least 0.5 mol%, preferably at least 1 mol%.

The optional monomer that can be included in the component (a) is not particularly limited as long as it is a monomer that can be cationically polymerized with isobutylene or isoprene. Examples of the optional monomer include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethylstyrene, and vinyltoluene And aromatic vinyl compounds such as p-tert-butylstyrene; and 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, chloroprene (2 Conjugated dienes such as -chloro-1,3-butadiene); One or more of these can be used as the optional monomer. The content of the structural unit derived from any monomer of the component (a) is usually 5 mol% or less, preferably 2.5 mol% or less.

Structural units derived from isoprene of the above copolymer and structural units derived from an arbitrary monomer such as a conjugated diene have a carbon-carbon double bond. The method for obtaining the component (a) by crosslinking the double bond in the copolymer to obtain the component (a) is not particularly limited, and can be performed by a known method using an arbitrary catalyst. Examples of the catalyst include a phenol resin, zinc oxide, and a compound containing a hydrosilyl group. Among them, a hydrosilyl group-containing compound is preferable from the viewpoint of suppressing coloring and odor.

The hydrosilyl group-containing compound is not particularly limited except that it has a hydrosilyl group, and any compound having an arbitrary hydrosilyl group can be used. As the hydrosilyl group-containing compound, a hydrosilyl group-containing polysiloxane is preferable from the viewpoint of crosslinkability. The number of hydrosilyl groups in the hydrosilyl group-containing polysiloxane is preferably 3 or more, more preferably 5 or more, from the viewpoint of crosslinkability. The number of structural units derived from siloxane is preferably 500 or less, more preferably 100 or less, from the viewpoint of miscibility with the component (a) and the like. On the other hand, from the viewpoint of crosslinkability, the number is preferably 10 or more, more preferably 20 or more.

In crosslinking the copolymer using the hydrosilyl group-containing compound, a hydrosilylation catalyst may be used for the purpose of accelerating the reaction. Examples of the hydrosilylation catalyst include radical generators such as organic peroxides and azo compounds; and transition metal catalysts. One or more of these can be used as the hydrosilylation catalyst.

(B1) Hydrogenated product of a block copolymer of an aromatic vinyl compound and a conjugated diene compound:
As the component (b), a hydrogenated product of (b1) a block copolymer of an aromatic vinyl compound and a conjugated diene compound can be used. When the above component (b1) is used, the compression set resistance and the flexibility become particularly good.

The aromatic vinyl compound is a polymerizable monomer having a polymerizable carbon-carbon double bond and an aromatic ring. Examples of the aromatic vinyl compound include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethylstyrene, vinyltoluene , And p-tert-butylstyrene. Of these, styrene is preferred. One or more of these can be used as the aromatic vinyl compound.

The conjugated diene is a polymerizable monomer having a structure in which two carbon-carbon double bonds are bonded by one carbon-carbon single bond. Examples of the conjugated diene include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, and chloroprene (2-chloro-1,3-butadiene). ) And so on. Of these, 1,3-butadiene and isoprene are preferred. One or more of these can be used as the conjugated diene.

The component (b1) is preferably one or more polymer blocks A mainly composed of an aromatic vinyl compound, preferably two or more polymer blocks A from the viewpoint of mechanical strength and moldability, and a polymer mainly composed of a conjugated diene compound. It is a block copolymer comprising at least one united block B. For example, a block copolymer having a structure such as AB, ABA, BABA, and ABABA can be given.

The content of the structural unit derived from the aromatic vinyl compound as the component (b1) is preferably from 5 to 60% by mass, more preferably from 20 to 50% by mass, from the viewpoint of heat resistance.

The polymer block A is a polymer block composed of only an aromatic vinyl compound or a copolymer block of an aromatic vinyl compound and a conjugated diene compound. When the polymer block A is a copolymer block, the content of the structural unit derived from the aromatic vinyl compound in the polymer block A is usually 50% by mass or more, and preferably 70% by mass from the viewpoint of heat resistance. %, More preferably 90% by mass or more. The distribution of the structural units derived from the conjugated diene compound in the polymer block A is not particularly limited and is arbitrary. When there are two or more polymer blocks A, they may have the same structure or different structures.

The polymer block B is a polymer block composed of only a conjugated diene compound or a copolymer block of an aromatic vinyl compound and a conjugated diene compound. When the polymer block B is a copolymer block, the content of the structural unit derived from the conjugated diene compound in the polymer block B is usually 50% by mass or more, and preferably 70% by mass from the viewpoint of flexibility. The content is more preferably 90% by mass or more. The distribution of the structural units derived from the aromatic vinyl compound in the polymer block is not particularly limited, and is arbitrary. The mode of bonding between the conjugated diene compound and the conjugated diene compound (hereinafter, sometimes abbreviated as microstructure) is not particularly limited and is arbitrary. When there are two or more polymer blocks B, they may have the same structure or different structures.

The hydrogenation rate of the component (b1) (the number of carbon-carbon double bonds in the block copolymer of an aromatic vinyl compound and a conjugated diene compound before hydrogenation, with respect to the number of carbon-carbon double bonds, Is not particularly limited, but may be usually at least 50 mol%, preferably at least 70 mol%, more preferably at least 90 mol%, from the viewpoint of heat resistance.

When the conjugated diene polymer block of the component (b) is a butadiene polymer block, the microstructure of the 1,2-bond is preferably from 20 to 50 mol%, more preferably from the viewpoint of flexibility. It may be 25-45 mol%. From the viewpoint of heat resistance, a 1,2-bond may be selectively hydrogenated.

When the conjugated diene polymer block of the component (b1) is a copolymer block of isoprene and butadiene, the microstructure of the 1,2-bond is preferably less than 50 mol% from the viewpoint of heat resistance. More preferably it may be less than 25 mol%, even more preferably less than 15 mol%.

When the conjugated diene polymer block of the component (b1) is an isoprene polymer block, from the viewpoint of flexibility, the microstructure may have 1,4-bonds, preferably 70 to 100 mol%. The hydrogenation rate is preferably 90 mol% or more from the viewpoint of heat resistance.

When the conjugated diene polymer block of the component (b1) is an isoprene polymer block, from the viewpoint of gas barrier properties, the microstructure has a sum of 1,2-bonds and 3,4-bonds of 80 mol%. It may be at least 90 mol%, more preferably at least 95 mol%. The hydrogenation rate is preferably 90 mol% or more from the viewpoint of heat resistance. Such a copolymer is often called a styrene-vinyl (ethylene-propylene) -styrene copolymer (V-SEPS). The glass transition temperature of the styrene-vinyl (ethylene-propylene) -styrene copolymer (V-SEPS) is preferably -40 to 20C.

In this specification, the glass transition temperature is maintained at 150 ° C. for 5 minutes using a Diamond DSC type differential scanning calorimeter manufactured by Perkin Elmer Japan Co., Ltd. in accordance with JIS K7121-1987, and is maintained at 10 ° C./min to −100 ° C. This is the midpoint glass transition temperature calculated from the curve of the last heating process measured by a program of cooling, holding at −50 ° C. for 3 minutes, and heating at 10 ° C./min to 150 ° C.

The number average molecular weight of the component (b1) is preferably from 80,000 to 1,500,000, more preferably from 100,000 to 550,000, from the viewpoint of moldability and compression set resistance. Preferably it is 100,000-400,000. The molecular weight distribution (mass average molecular weight / number average molecular weight) is preferably 10 or less from the viewpoint of mechanical properties.

Examples of the component (b1) include a styrene-ethylene-butene block copolymer (SEB), a styrene-ethylene-propylene block copolymer (SEP), and a styrene-ethylene-butene-styrene block copolymer (SEBS). Styrene-ethylene-propylene-styrene copolymer block (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), and styrene-vinyl (ethylene-propylene) -styrene copolymer (V- SEPS) and the like. Among them, styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), And styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS) are preferred.

(B2) a block copolymer of an aromatic vinyl compound and isobutylene:
As the component (b), (b2) a block copolymer of an aromatic vinyl compound and isobutylene can be used. When the above component (b2) is used, gas barrier properties are particularly improved.

The component (b2) includes at least one polymer block C mainly composed of an aromatic vinyl compound, preferably two or more polymer blocks from the viewpoint of mechanical strength, and one polymer block D mainly composed of isobutylene. A block copolymer comprising the above. For example, a block copolymer having a structure such as CD, CDC, CDCD, and CDDCC can be given.

The polymer block C is a polymer block composed of only an aromatic vinyl compound or a copolymer block of an aromatic vinyl compound and another monomer. When the polymer block C is a copolymer block, the content of the structural unit derived from the aromatic vinyl compound in the polymer block C is usually 50% by mass or more, and preferably 70% by mass from the viewpoint of heat resistance. %, More preferably 90% by mass or more. The other optional monomer is an optional monomer copolymerizable with the aromatic vinyl compound. Examples of the other optional monomers include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, and chloroprene (2-chloro-1,3 Conjugated dienes such as -butadiene); and isobutylene. One or more of these can be used as the other optional monomer. The distribution of the structural units derived from the other monomers in the polymer block C is not particularly limited and is arbitrary. When there are two or more polymer blocks C, they may have the same structure or different structures.

The polymer block D is a polymer block composed of only isobutylene or a copolymer block of isobutylene and any other monomer. In the case where the polymer block D is a copolymer block, the content of the structural unit derived from isobutylene in the polymer block D is usually 50% by mass or more, and is preferable from the viewpoint of compression set resistance and gas barrier properties. Is 70% by mass or more, more preferably 90% by mass or more. The other optional monomer is an optional monomer copolymerizable with isobutylene. Examples of the other optional monomers include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethylstyrene, vinyl Aromatic vinyl compounds such as toluene and p-tert-butylstyrene; and 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, chloroprene ( Conjugated dienes such as 2-chloro-1,3-butadiene). One or more of these can be used as the other optional monomer. The distribution of the structural units derived from the other monomers in the polymer block D is not particularly limited and is arbitrary. When there are two or more polymer blocks D, they may have the same structure or different structures.

Examples of the component (b2) include a styrene-isobutylene-styrene block copolymer (SIBS).

As the component (b), one or a mixture of two or more of these can be used.

The mixing ratio of the component (a) and the component (b) is 20% by mass or more (80% by mass or less of the component (b)) from the viewpoint of mechanical strength and compression set resistance. ), Preferably 25% by mass or more of the component (a) (75% by mass or less of the component (b)). On the other hand, from the viewpoints of flexibility, mechanical strength, and compression set resistance, the component (a) is 80% by mass or less (the component (b) 20% by mass or more), and preferably the component (a) 70% by mass. The following (the above component (b) is 30% by mass or more). Here, the total of the component (a) and the component (b) is 100% by mass.

(C) Polyolefin resin:
The component (c) is a polyolefin-based resin and functions to stabilize moldability. Examples of the polyolefin-based resin include polyethylene resins such as high-density polyethylene, linear low-density polyethylene, low-density polyethylene, and ethylene / α-olefin copolymer (ethylene-based plastomer); propylene homopolymer, propylene; Copolymers (block copolymers and random copolymers) with other small amounts of α-olefins (eg, ethylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, etc.) And polybutene-1; poly-4-methylpentene-1 and the like. Among them, a polypropylene-based resin is preferable from the viewpoint of heat resistance and moldability.

When the component (c) is a polypropylene resin, the enthalpy of fusion is preferably 60 J / g or less, more preferably 40 J / g or less, from the viewpoint of flexibility. From the viewpoint of mechanical strength, it is preferably at least 60 J / g, more preferably at least 80 J / g. From the viewpoint of heat resistance, it is preferably at least 100 J / g, more preferably at least 110 J / g. Further, the melting point is preferably 130 ° C. or more, more preferably 135 ° C. or more, from the viewpoint of heat resistance and mechanical strength. Although there is no particular upper limit for the melting point, it is usually about 167 ° C. because it is a crystalline propylene polymer.

In this specification, the melting enthalpy of the polypropylene-based resin is measured using a Diamond DSC differential scanning calorimeter manufactured by Perkin Elmer Japan Co., Ltd., kept at 230 ° C. for 5 minutes, cooled at −10 ° C./min to −10 ° C., Calculated from a second melting curve (melting curve measured in the last heating step) measured by a program of holding at -10 ° C for 5 minutes and heating at a rate of 10 ° C / minute to 230 ° C. The melting point was calculated from the peak top appearing on the highest temperature side in the second melting curve. FIG. 1 shows a calculation example.

The melt mass flow rate of the polypropylene-based resin measured at 230 ° C. and 21.18 N in accordance with JIS K 7210: 1999 is from the viewpoint of the balance between moldability and mechanical strength. When applying a resin composition to injection molding, it is preferably 0.1 to 100 g / 10 min, more preferably 0.3 to 30 g / 10 min. When the thermoplastic elastomer resin composition of the present invention is applied to extrusion molding, it is preferably 0.1 to 7 g / 10 min, more preferably 0.3 to 5 g / 10 min.

From the viewpoint of improving gas barrier properties and mechanical strength, a polyethylene resin having a density of preferably 930 Kg / m ³ or more, more preferably 950 to 965 Kg / m ³ , may be used as the component (c). In this specification, the density of the polyethylene resin is a value measured by an underwater substitution method in accordance with JIS K 7112: 1999.

The melt mass flow rate of the polyethylene resin measured at 190 ° C. and 21.18 N in accordance with JIS K 7210: 1999 is preferably 5 to 50 g / 10 min from the viewpoint of moldability and injection moldability. , More preferably 10 to 40 g / 10 min.

The compounding amount of the component (c) is preferably at least 5 parts by mass with respect to 100 parts by mass of the total of the components (a) and (b) from the viewpoint of moldability, heat resistance, and flexibility. Is 10 parts by mass or more. On the other hand, from the viewpoint of flexibility, the amount is 50 parts by mass or less, preferably 30 parts by mass or less.

(D) Softener for rubber:
The above component (d) can be used in the thermoplastic elastomer resin composition of the present invention, if desired. Flexibility can be increased. Examples of the component (d) include a softener for a non-aromatic rubber, a softener for an aromatic rubber, and an ester plasticizer. Among these, a softener for non-aromatic rubber is preferable from the viewpoint of compatibility.

The non-aromatic rubber softener is a non-aromatic mineral oil (hydrocarbon compound derived from petroleum or the like) or a synthetic oil (synthetic hydrocarbon compound), and is usually liquid, gel, or gum at room temperature. It is. Here, the term "non-aromatic" means that mineral oil is not classified as aromatic (the number of aromatic carbons is less than 30%) in the following categories. For synthetic oils, this means that no aromatic monomers are used.

The mineral oil used as the rubber softener is a mixture of any one or more of a paraffin chain, a naphthenic ring, and an aromatic ring, and a naphthenic ring having a naphthene ring carbon number of 30 to 45% is naphthenic, Those having an aromatic carbon number of 30% or more are called aromatic, and those which do not belong to the naphthene or aromatic system and whose paraffin chain carbon number occupies 50% or more of the total carbon number are called paraffinic. Called and distinguished.

Examples of the softener for non-aromatic rubber include paraffinic mineral oils such as linear saturated hydrocarbons, branched saturated hydrocarbons, and derivatives thereof; naphthenic mineral oils; hydrogenated polyisobutylene, polyisobutylene And synthetic oils such as polybutene; and the like.

The dynamic viscosity at 37.8 ° C of the softener for non-aromatic rubber is preferably 20 to 50,000 cSt, more preferably 20 to 1,000 cSt, from the viewpoint of moldability. The dynamic viscosity at 100 ° C. is preferably from 5 to 1,500 cSt, more preferably from 5 to 100 cSt, from the viewpoints of bleed-out resistance and heat resistance. The pour point is preferably −10 to −25 ° C. from the viewpoint of handleability during the production of the composition. The flash point (COC) is preferably 170 to 350 ° C. from the viewpoint of safety. The mass average molecular weight is preferably 100 to 2,000 from the viewpoint of bleed-out resistance.

Examples of commercially available non-aromatic rubber softeners include isoparaffinic hydrocarbon oil “NA Solvent (trade name)” manufactured by NOF Corporation and n-paraffinic process oil “Diana Process Oil PW” manufactured by Idemitsu Kosan Co., Ltd. -90 (trade name) "and" Diana Process Oil PW-380 (trade name) ", Idemitsu Petrochemical Co., Ltd. synthetic isoparaffinic hydrocarbon" IP-Solvent 2835 (trade name) ", and Sanko Chemical Industry Co., Ltd. -Paraffin-based process oil "Neothiozole (trade name)" and the like. Among these, from the viewpoint of compatibility, a paraffinic mineral oil is preferable, and a paraffinic mineral oil having a small number of aromatic carbons is more preferable. One or more of these can be used as the component (d).

The amount of the component (d) is preferably 100 parts by mass or less, more preferably 60 parts by mass, from the viewpoint of bleed resistance, based on 100 parts by mass of the total of the components (a) and (b). It is as follows. On the other hand, the lower limit of the amount of the component (d) is not particularly specified since it is an optional component, but may be preferably 5 parts by mass or more, more preferably 20 parts by mass or more, from the viewpoint of obtaining the effect of improving flexibility. .

The thermoplastic elastomer resin composition of the present invention may further contain an inorganic filler as far as the object of the present invention is not violated. It has an effect of improving the tensile strength and has an economic advantage by increasing the amount. Examples of the inorganic filler include calcium carbonate, talc, magnesium hydroxide, mica, clay, barium sulfate, natural silicic acid, synthetic silicic acid (white carbon), titanium oxide, and carbon black. One or more of these can be used as the inorganic filler. The amount of the inorganic filler is usually 50 parts by mass or less, with the total amount of the components (a) to (d) being 100 parts by mass.

In the thermoplastic elastomer resin composition of the present invention, phenol-based, phosphorus-based, and sulfur-based antioxidants; antioxidants, light stabilizers, and ultraviolet absorbers, to the extent that they do not violate the purpose of the present invention. Glidants such as acid amides, fatty acids, metal salts of fatty acids, waxes, silicone oils and modified silicone oils; nucleating agents such as metal salts of aromatic phosphates and gerols; electrification of glycerin fatty acid esters and the like Various additives such as an inhibitor, various organic / inorganic flame retardants, and a copper damage inhibitor can be further included. These additives are compatible with the above-mentioned components (a) to (c), which are essential components of the thermoplastic elastomer composition of the present invention, in order to prevent troubles such as bleeding out on the surface of the molded article. Are preferred.

The thermoplastic elastomer resin composition of the present invention can be obtained by melt-kneading the above components (a) to (c) and optional components used as desired using an arbitrary melt kneader. Any manufacturing method may be adopted as long as each component of the composition is substantially uniformly dispersed, and there is no limitation. For example, each component of the composition is dry-blended or hot-blended using a Henschel mixer, a ribbon blender, a tumbler mixer, or the like, and then a batch kneader such as a pressure kneader or a mixer; a co-kneader, a co-rotating twin-screw extruder. Kneader such as an extruder, a counter-rotating twin-screw extruder; a calendar roll kneader; and a kneader arbitrarily combining these.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.

Measurement method (1) Injection moldability:
Using an injection molding machine having a mold clamping force of 120 tons, a resin temperature of 230 ° C., a mold temperature of 40 ° C., an injection speed of 55 mm / sec, an injection pressure of 600 kg / cm ² , a holding pressure of 400 kg / cm ² , an injection time of 6 seconds, A sheet having a length of 13.5 cm, a width of 13.5 cm and a thickness of 2 mm was molded under the condition of a cooling time of 15 seconds. The appearance such as delamination, surface layer peeling, sink mark, deformation, and presence or absence of a flow mark was visually observed and evaluated according to the following criteria.
A: There is no defect at all.
：: Only a slight flow mark is recognized, and there is no other problem.
Δ: Flow mark and sink mark are observed.
X: Poor appearance.

(2) Hardness:
Using the injection sheet obtained above, a press sheet having a thickness of 6 mm was prepared by hot pressing under the conditions of preheating at 220 ° C. for 3 minutes and pressing at 220 ° C. for 3 minutes. Using the obtained press sheet as a sample, a 15-second value of durometer hardness (type A) was measured according to JIS K 6253-2012.

(3) Compression set 1 (compression deformation resistance 1 under high temperature environment):
According to JIS K 6262-2003, a 6 mm-thick press sheet obtained in the same manner as in the above test (2) was used as a test piece, and the measurement was performed under the conditions of 25% compression deformation, a temperature of 70 ° C, and 22 hours.

(4) Compression set 2 (compression deformation resistance 2 under high temperature environment):
All measurements were performed in the same manner as in the above test (3) except that the test temperature was changed from 70 ° C to 120 ° C.

(5) Bleed-out resistance:
After exposing the above-obtained injection sheet in a gear oven at 70 ° C. for 168 hours, the surface was visually observed or touched by hand, and evaluated according to the following criteria.
：: No stickiness is felt on the sheet surface. △: Stickiness is felt on the sheet surface. X: Stain is attached when touching the sheet surface.

(6) Oxygen permeability coefficient:
According to the gas chromatographic method of Appendix 2 of JIS K7126-1: 2006, the oxygen transmission coefficient was measured at a temperature of 23 ° C and a humidity of 0%. A 1 mm thick press sheet obtained by hot pressing under the conditions of preheating at 220 ° C. for 3 minutes and pressing at 220 ° C. for 3 minutes was used as the test piece. In the table of the results, the description of the unit (× 10 ⁻¹⁶ mol / m · sec · Pa) is omitted.

(7) Tensile test:
In accordance with JIS K 6251-2010, using a No. 3 dumbbell punched from the above-obtained 2 mm-thick injection sheet as a test piece, measurement was performed at a tensile speed of 500 mm / min.

Ingredients used:
Component (a):
(A-1) An uncrosslinked isobutylene rubber was obtained according to Production Example 1 of WO 2006/098142. Then, according to Production Example 3 of WO 2006/098142, except that the following (c-1) was used instead of HDPE and the following (d-2) was used instead of 100R, the component (a) 100 There was obtained an isobutylene-based elastic composition containing 10 parts by mass, 11 parts by mass of component (c), and 40 parts by mass of component (d).
(A-2) An isobutylene-based elastic composition was obtained in the same manner as (a-1) except that the following (c-4) was used as HDPE and the following (d-3) was used instead of 100R. Was.
(A-3) An isobutylene-based elastic composition was obtained in the same manner as in the above (a-1) except that the following (c-4) was used as HDPE.

Component (b):
(B-1) Kuraray Co., Ltd. styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS) “SEPTON4077 (trade name)”. The content of the structural unit derived from styrene is 30% by mass, the number average molecular weight is 280000, and the molecular weight distribution (mass average molecular weight / number average molecular weight) is 1.23.
(B-2) Kaneka Corporation's styrene-isobutylene-styrene block copolymer (SIBS) “SIBSTAR103T (trade name)”. The content of the structural unit derived from styrene is 31% by mass, the number average molecular weight is 92,000, the molecular weight distribution (mass average molecular weight / number average molecular weight) is 1.10, and the durometer hardness (type A, 15 seconds value) is 57.
(B-3) Kuraray Co., Ltd. styrene-vinyl (ethylene-propylene) -styrene copolymer (V-SEPS) “HIBLER KL-7135 (trade name)”. 33% by mass of a structural unit derived from styrene, durometer hardness (type A, 15 seconds value) 68, glass transition temperature -15 ° C.

Component (c):
(C-1) Prime Polymer's polypropylene resin "Prime Polypro J106MG (trade name)". Enthalpy of fusion 100 J / g, melting point 160 ° C, melt mass flow rate (230 ° C, 21.18N) 15 g / 10 minutes.
(C-2) Polypropylene resin “PB270A (trade name)” manufactured by Sun Allomer Co., Ltd. Melting enthalpy: 98 J / g, melting point: 161 ° C., melt mass flow rate (230 ° C., 21.18 N) 0.7 g / 10 min.
(C-3) Polypropylene resin “Adflex Q-100F (trade name)” manufactured by Sun Allomer Co., Ltd. Melting enthalpy: 36 J / g; melting point: 142 ° C; melt mass flow rate (230 ° C, 21.18 N): 0.6 g / 10 min.
(C-4) High-density polyethylene “Novatech HJ490 (trade name)” of Japan Polyethylene Corporation. Density: 960 kg / m ³ , melt mass flow rate (190 ° C., 21.18 N) 20 g / 10 min.

Component (d):
(D-1) Idemitsu Kosan Co., Ltd. n-paraffinic process oil "Diana Process Oil PW-380 (trade name)". Mw 750, Mn 652, Mw / Mn 1.15.
(D-2) Polybutene-based synthetic oil "Nisseki Polybutene HV-300 (trade name)" of JX Nippon Oil & Energy Corporation. Mn 1400.
(D-3) N-paraffinic process oil "Diana Process Oil PW-100 (trade name)" of Idemitsu Kosan Co., Ltd. Mw 720, Mn 540, Mw / Mn 1.33.

Examples 1 to 15 and Comparative Examples 1 to 9
A compound having a compounding ratio (parts by mass) shown in any one of Tables 1 to 4 was screwed at a screw rotation speed of 200 rpm using a twin screw extruder having a diameter of 28 mm, L / D = 42, manufactured by Nippon Steel Corporation, and a die outlet. The mixture was melt-kneaded at a resin temperature of 220 ° C., and pellets of a thermoplastic elastomer resin composition were obtained by a strand cut method. The following tests (1) to (7) were performed. The results are shown in any one of Tables 1 to 4.

The thermoplastic elastomer resin composition of the present invention is excellent in gas barrier properties, resistance to compression deformation in a high-temperature environment, flexibility, and mechanical strength, and has good moldability. Also, it has excellent bleed-out resistance.
On the other hand, the comparative examples are insufficient in at least one of gas barrier properties, resistance to compression deformation in a high-temperature environment, flexibility, mechanical strength, moldability, and bleed-out resistance.

It is a conceptual diagram of the 2nd melting curve measured by the differential scanning calorimeter.

1: melting point curve 2: baseline 3: area representing melting enthalpy 4: melting point 5: integration start point of melting enthalpy calculation 6: integration end point of melting enthalpy calculation

Claims (5)

(A) 20 to 80% by mass of a crosslinked elastic body having a structural unit derived from isobutylene;
(B) 80 to 20% by mass of a styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), wherein the total of the components (a) and (b) is 100% by mass. , 100 parts by mass of a resin composition;
(C) 10 to 50 parts by mass of a polypropylene resin;
(D) 5-100 parts by mass of a softener for rubber;
Unrealized, wherein said component (d) Rubber softener is including thermoplastic elastomer resin composition paraffinic mineral oil.
The thermoplastic elastomer resin composition according to claim 1, wherein the component (a) is a crosslinked elastic body obtained by crosslinking using a hydrosilyl group-containing compound.
The thermoplastic elastomer resin composition according to claim 1 or 2, wherein the paraffinic mineral oil has a dynamic viscosity at 100C of 5 to 100 cSt (excluding 100 cSt).
A medical device comprising the thermoplastic elastomer resin composition according to claim 1.
A food appliance comprising the thermoplastic elastomer resin composition according to claim 1.