JP6814691B2 - Thermoplastic elastomer composition - Google Patents

Description

The present invention relates to a thermoplastic elastomer composition used for a wide range of industrial materials requiring conductivity such as an antistatic mat, an antistatic grip, an electromagnetic wave suppression sheet, a cable coating, and a touch pen, and the thermoplastic elastomer composition. The present invention relates to a molded product obtained by heat molding.

Patent Document 1 discloses a resin composition containing a styrene-based thermoplastic elastomer and / or an olefin-based thermoplastic elastomer and a conductive filler, which is flexible and has a volume resistivity of 10 ² to 10 ¹² Ω · cm. ing.

Japanese Unexamined Patent Publication No. 10-226742

However, the resin composition described in Patent Document 1 has a drawback that it does not have sufficient heat resistance and cannot be used for applications requiring a high degree of heat resistance such as automobile applications.

An object of the present invention is to provide a thermoplastic elastomer composition having high conductivity and excellent flexibility and heat resistance, and a molded product made from the composition.

The present invention
[1] A thermoplastic elastomer composed of a polymer block (A) containing a structural unit derived from styrenes and a maleimide compound, and a block copolymer having an acrylic polymer block (B), and 100 volumes of the thermoplastic elastomer. A thermoplastic elastomer composition containing 1 to 100 parts by volume of a conductivity-imparting agent, wherein the polymer block (A) is a maleimide compound in all structural units of the polymer block (A). A thermoplastic elastomer composition having a structural unit derived from 30% by mass or more and 99% by mass or less and having a glass transition temperature (Tg) of 150 ° C. or higher, and [2] the above [1]. The present invention relates to a molded product obtained by heat-molding the thermoplastic elastomer composition of the above.

The thermoplastic elastomer composition of the present invention has high conductivity, and has the effect of being excellent in flexibility and heat resistance.

The thermoplastic elastomer composition of the present invention (hereinafter, also referred to as the composition of the present invention) includes a polymer block (A) containing a structural unit derived from styrenes and a maleimide compound, and an acrylic polymer block (B). It contains a thermoplastic elastomer made of a block copolymer having the above, and a conductivity-imparting agent.

<Polymer block (A)>
As described above, the polymer block (A) has a structural unit derived from styrenes and a maleimide compound.

The styrenes include styrene and its derivatives. Specific compounds include styrene, α-methylstyrene, β-methylstyrene, vinyltoluene, vinylxylene, vinylnaphthalene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, and m-. Ethylstyrene, p-ethylstyrene, pn-butylstyrene, p-isobutylstyrene, pt-butylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-chloromethylstyrene, p- Examples thereof include chloromethylstyrene, o-chlorostyrene, p-chlorostyrene, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, divinylbenzene, etc., and one or more of these may be used. it can. By polymerizing a monomer containing styrenes, a structural unit derived from styrenes can be introduced into the polymer block (A).
Among the above, styrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-hydroxystyrene, m-hydroxystyrene, and p-hydroxystyrene are preferable from the viewpoint of polymerizable property. Further, α-methylstyrene, β-methylstyrene and vinylnaphthalene are preferable in that the Tg of the polymer block (A) can be increased and a block polymer having excellent heat resistance can be obtained.

In the polymer block (A), the proportion of the structural units derived from the styrenes is preferably 1% by mass or more and 70% by mass or less in the total structural units of the polymer block (A). It is more preferably 5% by mass or more and 70% by mass or less, further preferably 10% by mass or more and 70% by mass or less, and further preferably 20% by mass or more and 60% by mass or less. Further, for example, it may be 20% by mass or more and 40% by mass or less.
When the structural unit derived from styrenes is 1% by mass or more, a block copolymer having excellent moldability can be obtained. On the other hand, if it is 70% by mass or less, the required amount of the structural unit derived from the maleimide compound described later can be secured, so that a block copolymer having excellent heat resistance and oil resistance can be obtained.

The maleimide compound includes a maleimide and an N-substituted maleimide compound. Examples of the N-substituted maleimide compound include N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, N-isobutylmaleimide, and N-tert-butylmaleimide. N-alkyl-substituted maleimide compounds such as N-pentylmaleimide, N-hexylmaleimide, N-heptylmaleimide, N-octylmaleimide, N-laurylmaleimide, N-stearylmaleimide; N-cyclopentylmaleimide, N-cyclohexylmaleimide and the like. N-Cycloalkyl-substituted maleimide compounds; N-phenylmaleimide, N- (4-hydroxyphenyl) maleimide, N- (4-acetylphenyl) maleimide, N- (4-methoxyphenyl) maleimide, N- (4-ethoxyphenyl) ) N-aryl-substituted maleimide compounds such as maleimide, N- (4-chlorophenyl) maleimide, N- (4-bromophenyl) maleimide, N-benzylmaleimide, etc., and one or more of these may be mentioned. Can be used. By polymerizing a monomer containing a maleimide compound, a structural unit derived from the maleimide compound can be introduced into the polymer block (A).

Among the above, the compound represented by the following general formula (1) is preferable in that the obtained block copolymer has more excellent oil resistance.

[In the formula, R ¹ represents hydrogen, an alkyl group having 1 to 3 carbon atoms, or PhR ² . However, Ph represents a phenyl group, and R ² represents a hydrogen, a hydroxy group, an alkoxy group having 1 to 2 carbon atoms, an acetyl group or a halogen. ]

In the polymer block (A), the ratio of the structural units derived from the maleimide compound is 30% by mass or more and 99% by mass or less in the total structural units of the polymer block (A). It is preferably 30% by mass or more and 95% by mass or less, more preferably 30% by mass or more and 90% by mass or less, and further preferably 40% by mass or more and 80% by mass or less. Further, for example, it may be 50% by mass or more, and further, for example, 60% by mass or more. Further, for example, it may be 75% by mass or less, and further, for example, it may be 70% by mass or less. Further, for example, it may be 50% by mass or more and 75% by mass or less, or 60% by mass or more and 70% by mass or less.
When the structural unit derived from the maleimide compound is less than 30% by mass, the heat resistance and oil resistance of the obtained block copolymer may not be sufficient. On the other hand, if it exceeds 99% by mass, the structural unit derived from the styrenes may be insufficient, resulting in insufficient fluidity and moldability.

At least one of the polymer block (A) and the acrylic polymer block (B) preferably has a crosslinkable functional group, and when the polymer block (A) contains a crosslinkable functional group, it is subjected to compression set. It is preferable because it is easy to obtain a block copolymer having a small value. The crosslinkable functional group may be introduced by using styrenes having a functional group such as a hydroxy group and / or a maleimide compound, or by copolymerizing a vinyl compound having a crosslinkable functional group. Can be done. Examples of the vinyl compound having a crosslinkable functional group include unsaturated carboxylic acid, unsaturated acid anhydride, hydroxy group-containing vinyl compound, epoxy group-containing vinyl compound, primary or secondary amino group-containing vinyl compound, and reactive silicon group. Examples include compounds. These compounds may be used alone or in combination of two or more.

Unsaturated carboxylic acids include (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, cinnamon acid, and monoalkyl esters of unsaturated dicarboxylic acids (maleic acid, fumaric acid, itaconic acid). Acids, citraconic acid, maleic anhydride, itaconic anhydride, monoalkyl esters such as citraconic anhydride) and the like can be mentioned. These compounds may be used alone or in combination of two or more.

Examples of unsaturated acid anhydrides include maleic anhydride, itaconic anhydride, citraconic anhydride and the like. These compounds may be used alone or in combination of two or more.

Examples of the hydroxy group-containing vinyl compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and (meth). ) 3-Hydroxybutyl acrylate, 4-hydroxybutyl (meth) acrylate, and mono (meth) acrylic acid esters of polyalkylene glycols such as polyethylene glycol and polypropylene glycol. These compounds may be used alone or in combination of two or more.

Examples of the epoxy group-containing vinyl compound include glycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth) acrylate. These compounds may be used alone or in combination of two or more.

Examples of the primary or secondary amino group-containing vinyl compound include amino groups such as aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, N-methylaminoethyl (meth) acrylate, and N-ethylaminoethyl (meth) acrylate. Containing (meth) acrylic acid ester; Amino group-containing (meth) acrylamide such as aminoethyl (meth) acrylamide, aminopropyl (meth) acrylamide, N-methylaminoethyl (meth) acrylamide, and N-ethylaminoethyl (meth) acrylamide. And so on.

Examples of the reactive silicon group-containing compound include vinylsilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinyldimethylmethoxysilanen; trimethoxysilylpropyl (meth) acrylate, and tri (meth) acrylate. Cyril group-containing (meth) acrylic acid esters such as ethoxysilylpropyl, methyldimethoxysilylpropyl (meth) acrylate, and dimethylmethoxysilylpropyl (meth) acrylate; silyl group-containing vinyl ethers such as trimethoxysilylpropyl vinyl ether; tri Examples thereof include silyl group-containing vinyl esters such as vinyl methoxysilylundecanoate. These compounds may be used alone or in combination of two or more.

In addition to the above, an oxazoline group or an isocyanate group can be introduced as a crosslinkable functional group by copolymerizing an oxazoline group-containing monomer or an isocyanate group-containing monomer.

Further, by copolymerizing a polyfunctional polymerizable monomer having two or more polymerizable unsaturated groups in the molecule, a polymerizable unsaturated group is introduced into the polymer block (A) as a crosslinkable functional group. obtain. The polyfunctional polymerizable monomer is a compound having two or more polymerizable functional groups such as a (meth) acryloyl group and an alkenyl group in the molecule, and is a polyfunctional (meth) acrylate compound, a polyfunctional alkenyl compound, and the like. Examples thereof include compounds having both (meth) acryloyl group and alkenyl group. Among these, allyl (meth) acrylate, isopropenyl (meth) acrylate, butenyl (meth) buthenyl acrylate, pentenyl (meth) acrylate, 2- (2-vinyloxyethoxy) ethyl (meth) acrylate, etc. When a compound having both a (meth) acryloyl group and an alkenyl group is used in the molecule of the above, the polymer block (A) is effectively polymerizable unsaturated due to the difference in the reactivity of the polymerizable unsaturated group. It is preferable in that a group can be introduced. These compounds may be used alone or in combination of two or more.

When the polymer block (A) has a crosslinkable functional group, the amount of the crosslinkable functional group introduced is preferably 0.01 mol% or more based on the total structural units of the polymer block (A), and more. It is preferably 0.1 mol% or more, more preferably 1.0 mol% or more, and particularly preferably 2.0 mol% or more. When the amount of the crosslinkable functional group introduced is 0.01 mol% or more, it becomes easy to obtain a block copolymer having a small value of compression set. On the other hand, from the viewpoint of controllability of the cross-linking reaction, the upper limit of the amount of the cross-linking functional group introduced is preferably 60 mol% or less, more preferably 40 mol% or less, still more preferably 20 mol% or less, and particularly. It is preferably 10 mol% or less. The amount of the crosslinkable functional group introduced can be in the range of 0.01 mol% or more and 60 mol% or less, preferably 0.1 mol% or more and 40 mol, based on the total structural units of the polymer block (A). It is in the range of% or less, more preferably 1.0 mol% or more and 20 mol% or less.

The polymer block (A) may have structural units derived from other monomers copolymerizable with the above-mentioned monomer units as long as the effects of the present invention are not impaired. .. Examples of other monomers include (meth) acrylic acid alkyl ester compounds, (meth) acrylic acid alkoxyalkyl ester compounds, and amide group-containing vinyl compounds. These compounds may be used alone or in combination of two or more.
Among these, an amide group-containing vinyl compound is preferable from the viewpoint that a block copolymer having more excellent oil resistance can be obtained.
In the polymer block (A), the proportion of the structural units derived from the other monomers shall be in the range of 0% by mass or more and 50% by mass or less in the total structural units of the polymer block (A). Is preferable. It is more preferably 5% by mass or more and 45% by mass or less, and further preferably 10% by mass or more and 40% by mass or less.

Specific examples of the (meth) acrylic acid alkyl ester compound include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, isopropyl (meth) acrylic acid, n-propyl (meth) acrylic acid, and n (meth) acrylic acid. -Butyl, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate , Linear or branched alkyl ester compounds of (meth) acrylic acid such as n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate and dodecyl (meth) acrylate; ) Cyclohexyl acrylate, methyl cyclohexyl (meth) acrylate, tert-butyl cyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, (meth) acrylic acid Examples thereof include aliphatic cyclic ester compounds of (meth) acrylic acid such as dicyclopentenyl and dicyclopentanyl (meth) acrylic acid.

Examples of the (meth) acrylate alkoxyalkyl ester compound include methoxymethyl (meth) acrylate, ethoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and n (meth) acrylate. -Propoxyethyl, n-butoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, ethoxypropyl (meth) acrylate, n-propoxypropyl (meth) acrylate, n-butoxypropyl (meth) acrylate, Examples thereof include methoxybutyl (meth) acrylate, ethoxybutyl (meth) acrylate, n-propoxybutyl (meth) acrylate, n-butoxybutyl (meth) acrylate and the like.

Examples of the amide group-containing vinyl compound include (meth) acrylamide, tert-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, and N-isopropyl (meth) acrylamide. , N, N-Dimethylaminopropyl (meth) acrylamide and (meth) acryloylmorpholin and other (meth) acrylamide derivatives; and N-vinylamide-based singles such as N-vinylacetamide, N-vinylformamide and N-vinylisobutylamide. Quantum and the like can be mentioned.

Examples of the monomer other than the above include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylate.

The glass transition temperature (Tg) of the polymer constituting the polymer block (A) is 150 ° C. or higher. Since Tg can contribute to heat resistance, for example, it may be 170 ° C. or higher, 180 ° C. or higher, 190 ° C. or higher, or 200 ° C. or higher. Furthermore, it may be 210 ° C. or higher, 220 ° C. or higher, or 230 ° C. or higher. If the Tg is less than 150 ° C., the heat resistance and oil resistance of the obtained block copolymer may be insufficient. Due to the limitation of the constituent monomer units that can be used, the upper limit of Tg is 350 ° C. Tg may also be, for example, 280 ° C. or lower, 270 ° C. or lower, and further, for example, 260 ° C. or lower.
The value of Tg can be obtained by differential scanning calorimetry (DSC) as described in Examples described later. It can also be calculated from the monomer units constituting the polymer block.

When the solubility parameter (SP value) of the polymer block (A) is 10.0 or more, it is preferable in that the oil resistance of the block copolymer becomes better. The SP value is more preferably 11.0 or more, further preferably 12.0 or more, still more preferably 13.0 or more.
The upper limit of the SP value of the polymer block (A) is not particularly limited, but is preferably 30 or less. Further, for example, the SP value may be 20.0 or less, or may be, for example, 18.0 or less.

Regarding the above SP value, R. F. It can be calculated by the calculation method described in "Polymer Engineering and Science" 14 (2), 147 (1974) written by Fedors. Specifically, the calculation method shown in the equation (1) is used.

δ: SP value ((cal / cm ³ ) ^1/2 )
ΔE _vap : Molar heat of vaporization of each atomic group (cal / mol)
V: Molar volume of each atomic group (cm ³ / mol)

<Acrylic polymer block (B)>
The acrylic polymer block (B) can be obtained by polymerizing a monomer containing an acrylic monomer. The acrylic monomer refers to an unsaturated compound having an acryloyl group such as an acrylic acid and an acrylic acid ester compound. Acrylic acid ester compounds include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, hexyl acrylate, 2-acrylate. Acrylic acid alkyl ester compounds such as ethylhexyl, octyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, stearyl acrylate; cyclohexyl acrylate, methyl cyclohexyl acrylate, tert-butyl cyclohexyl acrylate, cyclododecyl acrylate, etc. Acrylic acid aliphatic cyclic ester compounds; methoxymethyl acrylate, ethoxymethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, n-propoxyethyl acrylate, n-butoxyethyl acrylate, methoxypropyl acrylate, Acrylic acid alkoxyalkyl ester compounds such as ethoxypropyl acrylate, n-propoxypropyl acrylate, n-butoxypropyl acrylate, methoxybutyl acrylate, ethoxybutyl acrylate, n-propoxybutyl acrylate, n-butoxybutyl acrylate, etc. And so on. In addition to this, an acrylic acid ester compound having a functional group such as an amide group, an amino group, a carboxy group and a hydroxy group may be used.
Among these, an acrylic acid alkyl ester compound having an alkyl group having 1 to 12 carbon atoms or an alkoxyalkyl group having 2 to 8 carbon atoms is preferable in that a block copolymer having excellent flexibility can be obtained. In addition, from the viewpoint of heat resistance and oil resistance, the acrylic monomer is an acrylic acid alkyl ester compound (acrylic acid) having an alkyl group having 1 to 3 carbon atoms or an alkoxyalkyl group having 2 to 3 carbon atoms. More preferably, it contains an alkyl ester compound A) and an acrylic acid alkyl ester compound (acrylic acid alkyl ester compound B) having an alkyl group having 4 to 12 carbon atoms or an alkoxyalkyl group having 4 to 8 carbon atoms. The mass ratio of the acrylic acid alkyl ester compound A to the acrylic acid alkyl ester compound B (acrylic acid alkyl ester compound A / acrylic acid alkyl ester compound B) is preferably 10/90 to 90/10, more preferably 40/60 to 40. It is 85/15.

In the acrylic polymer block (B), the ratio of the structural units derived from the acrylic monomer is in the range of 20% by mass or more and 100% by mass or less in the total structural units of the acrylic polymer block (B). It is more preferably 50% by mass or more and 100% by mass or less, still more preferably 80% by mass or more and 100% by mass or less, and further preferably 90% by mass or more and 100% by mass or less.
In the acrylic polymer block (B), when the structural unit derived from the acrylic monomer is within the above range, a block copolymer that is good in terms of mechanical properties tends to be obtained.

As long as the effect of the present invention is not impaired, the acrylic polymer block (B) can use a monomer other than the acrylic monomer as a constituent monomer unit. As the monomer other than the acrylic monomer, a monomer having an unsaturated group other than the acryloyl group can be used, and a methacryloyl group-containing compound such as a methacrylic acid ester, an alkyl vinyl ester, an alkyl vinyl ether and the like can be used. Examples thereof include aliphatic or aromatic vinyl compounds such as styrenes.

The Tg of the polymer constituting the acrylic polymer block (B) is preferably 20 ° C. or lower from the viewpoint of the flexibility of the block copolymer. Further, for example, the temperature may be 10 ° C. or lower. The Tg is more preferably 0 ° C. or lower, and even more preferably −10 ° C. or lower. Due to the limitation of the constituent monomer units that can be used, the lower limit of Tg is −80 ° C.
Further, when Tg is −20 ° C. or lower, flexibility is ensured even in a low temperature environment, which is preferable. When cold resistance is taken into consideration, it is more preferably −30 ° C. or lower, and further preferably −40 ° C. or lower.

Further, when the SP value of the acrylic polymer block (B) is 9.9 or more, it is preferable in that the oil resistance of the block copolymer becomes better. The SP value is more preferably 10.0 or more, further preferably 10.1 or more, and particularly preferably 10.2 or more.
The upper limit of the SP value of the acrylic polymer block (B) is not particularly limited, but is preferably 20 or less.

Further, the polymer block (B) may contain a crosslinkable functional group, which is preferable because it is easy to obtain a block copolymer having high oil resistance. The crosslinkable functional group can be introduced, for example, by copolymerizing a vinyl compound having a crosslinkable functional group. Examples of the vinyl compound having a crosslinkable functional group include unsaturated carboxylic acid, unsaturated acid anhydride, hydroxy group-containing vinyl compound, epoxy group-containing vinyl compound, primary or secondary amino group-containing vinyl compound, and reactive silicon group. Examples include compounds. These compounds may be used alone or in combination of two or more.

When the polymer block (B) has a crosslinkable functional group, the amount of the crosslinkable functional group introduced is preferably 0.01 mol% or more based on the total structural units of the polymer block (B), and more. It is preferably 0.1 mol% or more, and more preferably 0.5 mol% or more. When the amount of the crosslinkable functional group introduced is 0.01 mol% or more, it becomes easy to obtain a block copolymer having high oil resistance. On the other hand, from the viewpoint of flexibility, the upper limit of the amount of the crosslinkable functional group introduced is preferably 20 mol% or less, more preferably 10 mol% or less, and further preferably 5 mol% or less. The amount of the crosslinkable functional group introduced can be in the range of 0.01 mol% or more and 20 mol% or less, preferably 0.1 mol% or more and 10 mol, based on the total structural units of the polymer block (B). It is in the range of% or less, and more preferably in the range of 0.5 mol% or more and 5 mol% or less.

<Block copolymer>
The block copolymer in the present invention has one or more of the polymer block (A) and the acrylic polymer block (B). When the block copolymer has two or more polymer blocks (A) and / or acrylic polymer blocks (B), the structure of each block may be the same or different. Further, the block copolymer may have a polymer block other than the polymer block (A) and the acrylic polymer block (B) as long as the effect of the present invention is not impaired.

The structure of the block copolymer is also not particularly limited, and various linear or branched block copolymers such as AB type diblock polymer or ABA type and ABC type triblock polymers can be used. From the viewpoint of obtaining good performance as an elastomer material, those having an A- (BA) n-type structure (n is an integer of 1 to 10) are preferable. The A- (BA) n-type structure is a polymer block (A)-(acrylic polymer block (B) -polymer block (A)) n-type structure, and when n is 1, the polymer block. It is an ABA triblock copolymer composed of (A) -acrylic polymer block (B) -polymer block (A).

In the block copolymer, the polymer block (A) acts as a hard segment, and the acrylic polymer block (B) acts as a soft segment. As a result, the block copolymer in the present invention exhibits excellent mechanical properties such as breaking elongation and breaking strength, and becomes a useful material as an elastomer.

The proportion of the polymer block (A) in the block copolymer is preferably 10% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 50% by mass or less.
The proportion of the acrylic polymer block (B) in the block copolymer is preferably 40% by mass or more and 90% by mass or less, and more preferably 50% by mass or more and 80% by mass or less.

In the composition of the present invention, the SP value of the polymer block (A) is preferably larger than the SP value of the acrylic polymer block (B), and the SP value of the polymer block (A) and the acrylic weight. The SP value of the coalesced block (B) preferably has a difference of 0.1 or more. When the SP values differ by 0.1 or more, both of them are appropriately phase-separated in the block copolymer, so that it is possible to exhibit excellent mechanical strength. The difference in SP value is more preferably 0.3 or more, further preferably 0.5 or more, further preferably 0.8 or more, and particularly preferably 1.0 or more. .. Further, from the viewpoint of manufacturing and the like, the difference in SP value is preferably 10 or less, and more preferably 5.0 or less.

Further, when the polymer block (A) has a crosslinkable functional group, an elastomer material having a smaller value of compression set can be obtained by cross-linking using the crosslinkable functional group. The cross-linking may be due to the reaction between the cross-linking functional groups introduced into the polymer block (A), or as described later, a cross-linking agent having a functional group capable of reacting with the cross-linking functional group is added. You may go. In the case of reaction between crosslinkable functional groups introduced into the polymer block (A), if a reactive silicon group is used as the crosslinkable functional group, the polymerization reaction for producing a block copolymer and the subsequent crosslinking reaction are efficient. Can be done

The number average molecular weight (Mn) of the block copolymer is preferably in the range of 10,000 or more and 500,000 or less. When the number average molecular weight is 10,000 or more, sufficient strength can be exhibited as an elastomer material. Further, if it is 500,000 or less, good moldability can be ensured. The number average molecular weight is more preferably in the range of 20,000 or more and 400,000 or less, and further preferably in the range of 50,000 or more and 200,000 or less.

Further, the molecular weight distribution (Mw / Mn) obtained by dividing the value of the weight average molecular weight (Mw) of the block copolymer by the value of the number average molecular weight (Mn) is 1.5 or less in terms of moldability. It is preferable to have. It is more preferably 1.4 or less, further preferably 1.3 or less, and even more preferably 1.2 or less. The lower limit of the molecular weight distribution is 1.0.

<Manufacturing method of block copolymer>
The block copolymer is not particularly limited as long as a block copolymer having the polymer block (A) and the acrylic polymer block (B) can be obtained, and a known production method shall be adopted. Can be done. For example, a method using various controlled polymerization methods such as living radical polymerization and living anionic polymerization, a method of coupling polymers having functional groups, and the like can be mentioned. Among these, the living radical polymerization method is preferable because it is easy to operate and can be applied to a wide range of monomers.

For the living radical polymerization, any process such as a batch process, a semi-batch process, a dry continuous polymerization process, or a continuous stirring tank type process (CSPR) may be adopted. In addition, the polymerization type can be applied to various aspects such as bulk polymerization using no solvent, solvent-based solution polymerization, aqueous emulsion polymerization, miniemulsion polymerization or suspension polymerization.
There are no particular restrictions on the type of living radical polymerization method, such as reversible addition-cleavage chain transfer polymerization method (RAFT method), nitroxy radical method (NMP method), atom transfer radical polymerization method (ATRP method), and organic tellurium compounds. Various polymerization methods such as a polymerization method using (TERP method), a polymerization method using an organic antimony compound (SBRP method), a polymerization method using an organic bismuth compound (BIRP method), and an iodine transfer polymerization method can be adopted. Among these, the RAFT method, the NMP method and the ATRP method are preferable from the viewpoint of controllability of polymerization and ease of implementation.

In the RAFT method, controlled polymerization proceeds through a reversible chain transfer reaction in the presence of a specific polymerization control agent (RAFT agent) and a general free radical polymerization initiator. As the RAFT agent, various known RAFT agents such as a dithioester compound, a xanthate compound, a trithiocarbonate compound and a dithiocarbamate compound can be used.
As the RAFT agent, a monofunctional agent having only one active site may be used, or a bifunctional or more agent may be used. It is preferable to use a bifunctional RAFT agent from the viewpoint that the block copolymer having the A- (BA) n-type structure can be easily obtained efficiently.
The amount of the RAFT agent used is appropriately adjusted depending on the monomer used, the type of the RAFT agent, and the like.

As the polymerization initiator used in the polymerization by the RAFT method, known radical polymerization initiators such as azo compounds, organic peroxides and persulfates can be used, but they are easy to handle for safety and are used during radical polymerization. An azo compound is preferable because side reactions are unlikely to occur.
Specific examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), and 2,2'-azobis (4-methoxy-2, 4-Dimethylvaleronitrile), dimethyl-2,2'-azobis (2-methylpropionate), 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-) Carbonitrile), 2,2'-azobis [N- (2-propenyl) -2-methylpropionamide], 2,2'-azobis (N-butyl-2-methylpropionamide) and the like.
Only one kind of the radical polymerization initiator may be used, or two or more kinds thereof may be used in combination.

The ratio of the radical polymerization initiator used is not particularly limited, but from the viewpoint of obtaining a polymer having a smaller molecular weight distribution, the amount of the radical polymerization initiator used relative to 1 mol of the RAFT agent is preferably 0.5 mol or less, and is 0. More preferably, it is 2 mol or less. Further, from the viewpoint of stably performing the polymerization reaction, the lower limit of the amount of the radical polymerization initiator used with respect to 1 mol of the RAFT agent is 0.01 mol. Therefore, the amount of the radical polymerization initiator used with respect to 1 mol of the RAFT agent is preferably in the range of 0.01 mol or more and 0.5 mol or less, and more preferably in the range of 0.05 mol or more and 0.2 mol or less.

The reaction temperature during the polymerization reaction by the RAFT method is preferably 40 ° C. or higher and 100 ° C. or lower, more preferably 45 ° C. or higher and 90 ° C. or lower, and further preferably 50 ° C. or higher and 80 ° C. or lower. When the reaction temperature is 40 ° C. or higher, the polymerization reaction can proceed smoothly. On the other hand, when the reaction temperature is 100 ° C. or lower, side reactions can be suppressed and restrictions on the initiators and solvents that can be used are relaxed.

In the NMP method, a specific alkoxyamine compound or the like having nitroxide is used as a living radical polymerization initiator, and the polymerization proceeds via the nitroxide radical derived from the specific alkoxyamine compound or the like. In the present disclosure, the type of nitroxide radical used is not particularly limited, but from the viewpoint of polymerization controllability when polymerizing a monomer containing an acrylate, a compound represented by the general formula (2) is used as the nitroxide compound. Is preferable.

{In the formula, R ¹ is an alkyl group or hydrogen atom having 1 to ² carbon atoms, R ² is an alkyl group or nitrile group having 1 to ² carbon atoms, and R ³ is − (CH ₂ ) m−, m. Is 0 to 2, and R ⁴ and R ⁵ are alkyl groups having 1 to 4 carbon atoms}

The nitroxide compound represented by the general formula (2) undergoes a primary dissociation by heating at about 70 to 80 ° C. and causes an addition reaction with a vinyl-based monomer. At this time, a polyfunctional polymerization precursor can be obtained by adding a nitroxide compound to a vinyl-based monomer having two or more vinyl groups. Next, the vinyl-based monomer can be subjected to living polymerization by secondary dissociation of the polymerization precursor under heating.
In this case, since the polymerization precursor has two or more active sites in the molecule, a polymer having a narrower molecular weight distribution can be obtained. From the viewpoint of efficiently obtaining the block copolymer having the A- (BA) n-type structure, it is preferable to use a bifunctional polymerization precursor having two active sites in the molecule.
The amount of the nitroxide compound used is appropriately adjusted depending on the monomer used, the type of the nitroxide compound, and the like.

When the block copolymer is produced by the NMP method, the nitroxide radical represented by the general formula (3) is contained in the range of 0.001 to 0.2 mol with respect to 1 mol of the nitroxide compound represented by the general formula (2). It may be added and polymerized.

{In the formula, R ⁴ and R ⁵ are alkyl groups having 1 to 4 carbon atoms. }

By adding 0.001 mol or more of the nitroxide radical represented by the general formula (3), the time for the concentration of the nitroxide radical to reach a steady state is shortened. As a result, the polymerization can be controlled to a higher degree, and a polymer having a narrower molecular weight distribution can be obtained. On the other hand, if the amount of the nitroxide radical added is too large, the polymerization may not proceed. A more preferable amount of the nitroxide radical added to 1 mol of the nitroxide compound is in the range of 0.01 to 0.5 mol, and a more preferable amount of addition is in the range of 0.05 to 0.2 mol.

The reaction temperature in the NMP method is preferably 50 ° C. or higher and 140 ° C. or lower, more preferably 60 ° C. or higher and 130 ° C. or lower, further preferably 70 ° C. or higher and 120 ° C. or lower, and particularly preferably 80 ° C. or higher and 120 ° C. It is as follows. When the reaction temperature is 50 ° C. or higher, the polymerization reaction can proceed smoothly. On the other hand, when the reaction temperature is 140 ° C. or lower, side reactions such as radical chain transfer tend to be suppressed.

In the ATRP method, a polymerization reaction is generally carried out using an organic halide as an initiator and a transition metal complex as a catalyst. The organic halide used as the initiator may be monofunctional or bifunctional or higher. It is preferable to use a bifunctional compound in that a block copolymer having an A- (BA) n-type structure can be easily obtained efficiently. Bromide and chloride are preferable as the type of halogen.

The reaction temperature in the ATRP method is preferably 20 ° C. or higher and 200 ° C. or lower, and more preferably 50 ° C. or higher and 150 ° C. or lower. When the reaction temperature is 20 ° C. or higher, the polymerization reaction can proceed smoothly.

By the living radical polymerization method, an A- (BA) n-type structure such as an ABA triblock copolymer composed of a polymer block (A) -acrylic polymer block (B) -polymer block (A) is obtained. In this case, for example, the target block copolymer may be obtained by sequentially polymerizing each block. In this case, first, as the first polymerization step, a monomer containing 1% by mass or more and 70% by mass or less of styrenes and 30% by mass or more and 99% by mass or less of the maleimide compound is polymerized to obtain a polymer block (A). .. Next, as a second polymerization step, the acrylic monomer is polymerized to obtain an acrylic polymer block (B). Further, as a third polymerization step, an ABA triblock copolymer is obtained by polymerizing a monomer containing 1% by mass or more and 70% by mass or less of styrenes and 30% by mass or more and 99% by mass or less of a maleimide compound. Can be done. In this case, it is preferable to use the above-mentioned monofunctional polymerization initiator or polymerization precursor as the polymerization initiator. By repeating the second polymerization step and the third polymerization step, a higher-order block copolymer such as a tetrablock copolymer can be obtained.

Further, when the product is produced by a method including the following two-step polymerization steps, the target product can be obtained more efficiently, which is preferable. That is, as a first polymerization step, an acrylic monomer is polymerized to obtain an acrylic polymer block (B), and then as a second polymerization step, styrene is present in the presence of the acrylic polymer block (B). Class 1 A polymer block (A) is obtained by polymerizing a monomer containing 1% by mass or more and 70% by mass or less, and 30% by mass or more and 99% by mass or less of a maleimide compound. As a result, an ABA triblock copolymer composed of the polymer block (A) -acrylic polymer block (B) -polymer block (A) can be obtained. In this case, it is preferable to use a bifunctional polymerization initiator or a polymerization precursor as the polymerization initiator. According to this method, the process can be simplified as compared with the case where each block is sequentially polymerized and produced. Further, by repeating the first polymerization step and the second polymerization step, a higher-order block copolymer such as a tetrablock copolymer can be obtained.

Polymerization of block copolymers may be carried out in the presence of a chain transfer agent, if necessary, regardless of the polymerization method.

Known chain transfer agents can be used, and specifically, ethanethiol, 1-propanethiol, 2-propanethiol, 1-butanethiol, 2-butanethiol, 1-hexanethiol, 2-hexane. Thiol, 2-methylheptane-2-thiol, 2-butylbutane-1-thiol, 1,1-dimethyl-1-pentanethiol, 1-octanethiol, 2-octanethiol, 1-decanethiol, 3-decanethiol, 1-Undecane thiol, 1-Dodecane thiol, 2-Dodecane thiol, 1-Tridecane thiol, 1-Tetradecane thiol, 3-Methyl-3-undecane thiol, 5-Ethyl-5-Decan thiol, tert-Tetradecane thiol, -In addition to alkylthiol compounds having an alkyl group having 2 to 20 carbon atoms such as hexadecanethiol, 1-heptadecanethiol and 1-octadecanethiol, mercaptoacetic acid, mercaptopropionic acid, 2-mercaptoethanol and the like can be mentioned. One or more of the above can be used.

A known polymerization solvent can be used in living radical polymerization. Specifically, aromatic compounds such as benzene, toluene, xylene and anisole; ester compounds such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate; ketone compounds such as acetone and methyl ethyl ketone; dimethylformamide, acetonitrile, dimethylsulfoxide, Examples include alcohol and water. In addition, bulk polymerization or the like may be carried out without using a polymerization solvent.

The content of the thermoplastic elastomer is preferably 60 to 99% by mass, more preferably 70 to 95% by mass, still more preferably 75 to 90% by mass in the composition of the present invention.

The composition of the present invention may contain another block copolymer as a thermoplastic elastomer as long as the effect of the present invention is not impaired, but the content of the block copolymer is the block copolymer. Of the total amount of, it is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass or more.

<Conductivity imparting agent>
Examples of the conductivity-imparting agent include polymer-type antistatic agents and inorganic conductive fillers, and examples of the inorganic conductive filler include conductive carbon black, carbon fibers, carbon nanotubes, carbon nanofibers, graphite, powder or fibrous. Metals or metal oxides of As the conductivity-imparting agent in the present invention, an inorganic conductive filler is preferable, and conductive carbon black is more preferable, from the viewpoint of improving the heat resistance of the composition.

Examples of the conductive carbon black include acetylene black obtained by thermally decomposing acetylene gas, furnace black produced by furnace-type incomplete combustion using crude oil as a raw material, and Ketjen black. Unlike carbon black for pigments, which is added to paint or the like for the purpose of coloring, these conductive carbon blacks usually have a form in which fine particles are connected. The preferred one is Ketjen black from the viewpoint of easily lowering the volume resistivity.

The oil absorption of dibutyl phthalate (DBP) of conductive carbon black measured according to ASTM D2414 is preferably 30 ml / 100 g or more, and more preferably 100 to 1000 ml / 100 g.

The BET specific surface area of the conductive carbon black is preferably 50 to 3000 m ² / g, more preferably 200 to 2000 m ² / g.

A smaller particle size of the inorganic conductive filler is preferable because it can correspond to a thinner sheet shape, while a larger particle size reduces the surface area per volume and improves the fluidity during melt flow. preferable. From these viewpoints, the volume median particle diameter of the inorganic conductive filler is 0.1 to 500 μm, preferably 0.5 to 100 μm, more preferably 0.8 to 60 μm, still more preferably 1.0. It is ~ 20 μm. As a method for measuring the particle size, it is known that it can be measured by various measurement principles such as a Coulter counter, a centrifugal sedimentation type, and a laser diffraction type, such as image analysis based on electron microscope observation. It is also known that there are differences in the numerical values obtained by the principle. In the present invention, the median diameter in the volume-based particle size distribution by image analysis based on electron microscope observation is defined as the volume median particle size (D ₅₀ ), but the particle size values measured by other measurement principles are based on common technical knowledge. It is also possible to convert and use it.

The specific gravity of the inorganic conductive filler means a true specific gravity, and from the viewpoint of conductivity, 1 or more is preferable, and 2 or more is preferable. Further, from the viewpoint of dispersibility, 10 or less is preferable, and 4 or less is preferable. From these viewpoints, the specific gravity of the inorganic conductive filler is preferably 1 to 10 and preferably 2 to 4 from the viewpoint of dispersibility and conductivity.

As a polymer-type antistatic agent, a polymer having a polyethylene oxide structure has been known for a long time, but an alkali metal such as a lithium salt or a sodium salt is added to a polymer having a basic skeleton such as polyether, polyester, polyamine, or polysulfide. What is called a polymer solid electrolyte in which a salt is dissolved is preferable from the viewpoint of higher conductivity. Specifically, for example, a method of using a solution of lithium imide in a propylene glycol-based polyether polyol is disclosed in Japanese Patent Application Laid-Open No. 2002-146178, and the antistatic performance can be improved by mixing with a urethane monomer. It is disclosed that a urethane rubber having a urethane rubber can be obtained. In the thermoplastic elastomer used in the present invention, since the structural unit derived from the maleimide compound in the block copolymer has a high affinity for such an alkali metal salt, a special method such as mixing at the monomer stage is not adopted. However, the ionic conductivity of the polymer-type antistatic agent is easily exhibited, and the bleed-out of the polymer-type antistatic agent is unlikely to occur.

When a polymer-type antistatic agent is used, it is preferable that the flexibility of the composition is not impaired, and in some cases, the composition can be made more flexible.

Such polymeric antistatic agents are generally a variety of polymeric materials including a high concentration of polyether blocks, the ionic conductivity along the polyether, of 10 ⁸ ~10 ¹³ Ω / cm ² Produces surface intrinsic resistance. As the ionic species of such an ionic conductive polymer-type antistatic agent, sodium, lithium and the like are generally used, but some nonionic ones are also used. For the surface resistivity, the resistivity is measured at 5 points by a four-probe method based on JIS K7194 using a Lorester GP resistivity meter manufactured by Mitsubishi Chemical Analytech.

Examples of commercially available polymer-type antistatic agents include Perestat 230, VH230, 303, 300 manufactured by Sanyo Chemical Industries, Ltd., Sanconol TBX35, TBX25, TBX310, TBX320, TBX8210 manufactured by Sanko Chemical Industries, Ltd. and the like.

The content of the conductivity-imparting agent in the composition of the present invention is preferably as small as possible because the melt fluidity of the composition is high, while when it is large, the conductivity of the composition is high. From these viewpoints, the content of the conductivity-imparting agent is 1 to 100 parts by volume, preferably 2 to 50 parts by volume, and more preferably 5 to 40 parts by volume with respect to 100 parts by volume of the thermoplastic elastomer. ..

The effect of the conductivity-imparting agent tends to appear mainly based on the surface area rather than the mass of the conductivity-imparting agent, and in that sense, the ratio of the thermoplastic elastomer to the conductivity-imparting agent is higher than the mass part. It is possible to better reflect the tendency of the effect if it is defined by the volume part. When the specific gravity of each of the thermoplastic elastomer and the conductivity-imparting agent is known, the mass part can be converted into the volume part by the specific gravity. The volume part of the conductivity-imparting agent can be calculated from the true specific gravity.

It is known that the hardness increases when an imparting agent is added to the elastomer. However, in the combination of the thermoplastic elastomer of the present invention and the conductivity imparting agent, the particle size and volume of the conductivity imparting agent are within the above ranges. When limited to, the surface hardness of the composition is not so large, and the flexibility can be maintained.

<Elastomer composition>
The composition of the present invention may be in the form of a composition containing known additives and the like, if necessary. In particular, when the block copolymer contains a crosslinkable functional group in at least one of the polymer block (A) and the acrylic polymer block (B), further, a crosslinker and a crosslink accelerator capable of reacting with the functional group. Etc. are preferably contained.

When the block copolymer contains a structural unit derived from a crosslinkable monomer having a carboxyl group, a polyvalent amine, a polyfunctional isocyanate or the like is preferably used as the crosslinker.

Examples of the polyvalent amine include aliphatic diamine compounds such as hexamethylenediamine, hexamethylenediamine carbamate, N, N'-dicinnamylidene-1,6-hexanediamine; and alicyclic type such as 4,4'-methylenebiscyclohexylamine carbamate. Diamine compounds; 4,4'-methylene dianiline, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-(m-phenylenediisopropylidene) dianiline, 4,4'-(p-phenylenedi) Isopropylidene) dianiline, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 4,4'-diaminobenzanilide, m-xylylene diamine, p-xylylene diamine, 1,3,5 Examples thereof include aromatic diamine compounds such as −benzenetriamine and 1,3,5-benzenetriaminomethyl.

Examples of the polyfunctional isocyanate include hexamethylene diisocyanate, dimethyldiphenylenediisocyanate, and isophorone diisocyanate.

When polyvalent amines are used, guanidine compounds such as 1,3-di-o-tolylguanidine and 1,3-diphenylguanidine; imidazole compounds such as 2-methylimidazole and 2-phenylimidazole; phosphates, carbonates and bicarbonates. , Salts of weak acids such as alkali metal salts (Li, Na, K) of acids such as stearic acid and lauric acid; triethylenediamine, 1,8-diazabicyclo- [5.4.0] undecene-7 and the like third. Secondary amines; Tertiary phosphine compounds such as triphenylphosphine and tri (methyl) phenylphosphine; cross-linking aids such as quaternary onium salts such as tetrabutylammonium bromide, tetrabutylammonium chloride, octadecyltrin-butylammonium bromide and the like. It is preferable to use in combination.

When the block copolymer contains a structural unit derived from a crosslinkable monomer having an epoxy group, the crosslinking agent includes an organic carboxylic acid ammonium salt, a dithiocarbamate, a polyvalent carboxylic acid or an anhydride, and a fourth. A combination with a quaternary ammonium salt or a phosphonium salt is preferably used.

Examples of the ammonium benzoate salt include ammonium benzoate and the like.

Examples of the dithiocarbamate include zinc salts such as dimethyldithiocarbamic acid, diethyldithiocarbamic acid and dibenzyldithiocarbamic acid, iron salts and tellurium salts.

Examples of the polyvalent carboxylic acid include malonic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, maleic acid, citric acid, tartaric acid, phthalic acid and the like. Examples of the quaternary ammonium salt include tetraethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide, n-dodecyltrimethylammonium bromide, octadecyltrimethylammonium bromide and the like. Examples of the phosphonium salt include triphenylbenzylphosphonium chloride, triphenylbenzylphosphonium bromide, triphenylbenzylphosphonium iodide, triethylbenzylphosphonium chloride, tetrabutylphosphonium bromide and the like.

When the block copolymer contains a structural unit derived from a crosslinkable monomer having a hydroxyl group, a polyfunctional isocyanate or the like is preferably used as the crosslinker.

When the block copolymer contains a structural unit derived from a crosslinkable monomer having a primary or secondary amino group, a polyfunctional isocyanate, a polyfunctional glycidyl compound and the like are preferably used as the crosslinking agent.

When the block copolymer contains a polymerizable unsaturated group, a dithiol compound such as 1,2-ethanedithiol, 1,4-butanethiol, 1,10-decanethiol, 1,4-benzenethiol, or ethane- En-thiol reactions with polyvalent thiols such as trithiol compounds such as 1,1,1-trithiol and 1,3,5-benzenetrithiol can be utilized.

When the cross-linking group of the block copolymer is a reactive silicon group, it is not necessary to add a cross-linking agent or the like because a cross-linking reaction occurs due to moisture.

The composition of the present invention may contain other thermoplastic resins or thermoplastic elastomers as long as the effects of the present invention are not impaired. Among them, the polar elastomer can improve the fusion property of the composition to the polar resin. The polar elastomer is not particularly limited, and examples thereof include NBR (nitrile rubber), polyurethane rubber, epichlorohydrin rubber, polyamide-based thermoplastic elastomer, and acrylic-based thermoplastic elastomer.

The composition of the present invention is, if necessary, a polyolefin resin such as polypropylene and polyethylene, a reinforcing agent such as silica, carbon fiber and glass fiber, an inorganic filler, and an insulating thermal conductivity, as long as the effects of the present invention are not impaired. Dispersants such as sex fillers and metal soaps, pigments, hydrated metal compounds, flame retardants such as red phosphorus, ammonium polyphosphate, antimony, silicone, antistatic agents, tackifiers, heat stabilizers, antioxidants, photostabilizers It may contain various additives such as an agent, an ultraviolet absorber, an antiblocking agent, a sealing property improving agent, a mold release agent, a coloring agent, and a fragrance.

The composition of the present invention is obtained by mixing, for example, a raw material containing a thermoplastic elastomer, a conductivity-imparting agent, and, if necessary, other additives and the like, and solidifying by cooling.

The term "mixing" as used in the present invention is not particularly limited as long as the various components are mixed well, and the various components may be dissolved in a soluble organic solvent and mixed, or by melt-kneading. It may be mixed.

In the case of melt mixing, a kneader or a general melt extruder can be used, and it is preferable to use a uniaxial extruder in order to improve the kneading state. As for the supply to the extruder, various components may be directly supplied to the extruder, or a mixture of various components in advance using a mixing device such as a Henschel mixer may be supplied from one hopper or two hoppers. Each component may be charged and dispensed while being quantified with a screw or the like under the hopper.

The thermoplastic elastomer composition can be used by directly molding the product obtained by melt-mixing into a molded product, or by using pellets or powder before making a molded product to be used as a final product, depending on the application. , Sheets and other intermediate products. For example, it is melt-mixed by an extruder and extruded into a strand, and while being cooled in cold water, it is cut into pellets such as cylinders and rice granules by a cutter. The obtained pellets can usually be made into a predetermined sheet-shaped molded product or mold-molded product by a molding method such as injection molding, extrusion molding, or press molding.

The storage elastic modulus of the composition of the present invention at 23 ° C. is preferably 1 × 10 ⁹ Pa or less, more preferably 1 × 10 ⁵ to 8 × 10 ⁸ Pa, still more preferably 1 × 10 from the viewpoint of flexibility. ^{It is 6 to} 5 × 10 ⁸ Pa. In the present invention, the storage elastic modulus is measured by 30 Hz dynamic viscoelasticity measurement.

From the viewpoint of heat resistance, the storage elastic modulus of the composition of the present invention at 150 ° C. is preferably 1 × 10 ⁷ Pa or more, more preferably 1 × 10 ⁷ to 1 × 10 ⁹ Pa, and further preferably 1.5. It is × 10 ^{7 to} 5 × 10 ⁸ Pa.

A molded product can be obtained by appropriately heat-molding the thermoplastic elastomer composition of the present invention according to a conventional method. The application of the molded product obtained by heat-molding the thermoplastic elastomer composition of the present invention is not particularly limited, and general styrene-based elastomer, polyolefin-based elastomer, polyurethane-based elastomer, polyamide-based elastomer, and acrylic-based elastomer. It can be used in fields where or polyester elastomers are used.

As the apparatus used for producing a molded product using the thermoplastic elastomer composition of the present invention, any molding machine capable of melting the molding material can be used. For example, a kneader, an extrusion molding machine, an injection molding machine, a press molding machine, a blow molding machine, a mixing roll and the like can be mentioned.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. Various physical properties of the raw materials used in Examples and Comparative Examples were measured by the following methods.

<Block copolymer>
[Composition ratio]
The composition ratio of the block copolymer is identified and calculated by dissolving the sample in deuterated chloroform and ^{1 1} H-NMR measurement.

[Glass transition temperature (Tg)]
The glass transition temperature (Tg) of a block copolymer is determined from the intersection of the baseline and the tangent at the inflection point of the heat flux curve obtained using a differential scanning calorimeter. The heat flux curve shows that about 10 mg of the sample is cooled to -50 ° C, held for 5 minutes, then warmed to 300 ° C at 10 ° C / min, subsequently cooled to -50 ° C, held for 5 minutes, and then 10 ° C /. It is obtained under the condition that the temperature is raised to 350 ° C. in min.
Measuring equipment: DSC6220 manufactured by SII Nanotechnology Co., Ltd.
Measurement atmosphere: Under a nitrogen atmosphere By measuring the differential scanning calorimetry of the block copolymer, inflection points corresponding to the polymer block (A) and the acrylic polymer block (B) were obtained, and each of them was obtained. The Tg of the polymer block can be determined.

[Measurement of molecular weight]
Gel permeation chromatography (GPC) measurement is performed under the conditions described below to obtain a polystyrene-equivalent number average molecular weight (Mn) and a weight average molecular weight (Mw). Further, the molecular weight distribution (Mw / Mn) is calculated from the obtained values.
○ Measurement conditions Column: Tosoh TSKgel SuperMultipore HZ-M x 4 Solvent: Tetrahydrofuran Temperature: 40 ° C
Detector: RI
Flow velocity: 600 μL / min

<Conductivity imparting agent>
[Medium volume particle size (D ₅₀ )]
For powdery particles, the length of any 100 particles is measured by image analysis using an electron microscope. Specifically, the average value of the longest diameter and the shortest diameter is used as the particle size of the particles, and the median diameter in the volume-based particle size distribution is calculated. When primary particles at the level of several nanometers are connected to form secondary particles such as Ketjen Black, the length of the secondary particles is measured.
[BET specific surface area]
According to the method of JIS Z8830, the BET nitrogen adsorption isotherm is measured using AUTOSORB-1 manufactured by Quantachrome, and the specific surface area is calculated from the amount of nitrogen adsorption using the BET multipoint method.

[Dibutyl phthalate (DBP) oil absorption]
Measured by a method according to ASTM D2414.

Synthesis example of RAFT agent 1
1-Dodecanethiol (42.2 g), 20% KOH aqueous solution (63.8 g), and trioctylmethylammonium chloride (1.5 g) were added to a eggplant-shaped flask, cooled in an ice bath, and carbon disulfide (15.9 g). ) And tetrahydrofuran (hereinafter also referred to as "THF") (38 ml) were added, and the mixture was stirred for 20 minutes. A THF solution (170 ml) of α, α'-dichloro-p-xylene (16.6 g) was added dropwise over 30 minutes. After reacting at room temperature for 1 hour, the mixture was extracted from chloroform, washed with pure water, dried over anhydrous sodium sulfate, and concentrated on a rotary evaporator. The obtained crude product is purified by column chromatography and then recrystallized from ethyl acetate to form 1,4-bis (n-dodecylsulfanylthiocarbonylsulfanylmethyl) benzene represented by the following formula (4). (Hereinafter also referred to as "DLBTTC") was obtained in a yield of 80%. ¹ The peak of the target product was confirmed at 7.2 ppm, 4.6 ppm, and 3.4 ppm by ¹ H-NMR measurement.

Production Example 1 of Acrylic Polymer Block (B)
RAFT agent (DLBTTC) (4.28 g), 2,2'-azobis (2-methylbutyronitrile) (hereinafter "ABN-E") obtained in Synthesis Example 1 in a 1 L flask equipped with a stirrer and a thermometer. (0.25 g), ethyl acrylate (651 g) and anisole (287 g) were charged, sufficiently degassed by nitrogen bubbling, and polymerization was started in a constant temperature bath at 60 ° C. After 3 hours and 30 minutes, the reaction was stopped by cooling to room temperature. The polymerization solution was reprecipitated and purified from hexane and vacuum dried to obtain a polymer B1. The molecular weight of the obtained polymer B1 was Mn69200, Mw75500, and Mw / Mn1.09 as measured by GPC (gel permeation chromatography) (in terms of polystyrene).

Production Example 2 of Acrylic Polymer Block (B)
In addition to ethyl acrylate, n-butyl acrylate and 2-methoxyethyl acrylate were used, and the same operation as in Production Example 1 was performed except that the amount charged was changed as shown in Table 1 and the reaction time was appropriately adjusted. Was carried out to obtain polymer B2. The molecular weight of the polymer B2 was measured and shown in Table 1. Further, when the composition ratio of ethyl acrylate, n-butyl acrylate and 2-methoxyethyl acrylate in the polymer was determined from ¹ H-NMR measurement, ethyl acrylate / n-butyl acrylate / 2-acrylate acrylate was determined. It was methoxyethyl (mass ratio) = 49/25/26.

Production Example 1 of Block Copolymer
Polymer B1 (87.0 g), ABN-E (0.10 g), N-phenylmaleimide (28.8 g), styrene (32.2 g) obtained in Production Example 1 in a 1 L flask equipped with a stirrer and a thermometer. ) And anisole (342 g) were charged, sufficiently degassed by nitrogen bubbling, and polymerization was started in a constant temperature bath at 60 ° C. After 3 hours, the reaction was stopped by cooling to room temperature. The polymerization solution was reprecipitated and purified from methanol and vacuum dried to obtain the block copolymer 1 shown in Table 3. As a result of measuring the molecular weight of the obtained block copolymer 1, Mn99000, Mw111,000 and Mw / Mn were 1.12.

The block copolymer 1 is a triblock copolymer having a structure of polymer block (A) -acrylic polymer block (B) -polymer block (A). ^{1 When} the composition ratio of N-phenylmaleimide and styrene in the polymer block (A) was determined from the H-NMR measurement, it was N-phenylmaleimide / styrene (mass ratio) = 51/49, and the polymer block (A). ) And the acrylic polymer block (B) were (A) / (B) (mass ratio) = 30/70. The block copolymer 1 was evaluated as an elastomer, and the results are shown in Table 3.

Production Example 2 of Block Copolymer
The types of raw materials to be charged into the flask and the amount to be charged were changed as shown in Table 2, and the same operations as in Production Example 1 were carried out except that the reaction time was appropriately adjusted to obtain block copolymers 2 to 4. The molecular weight of each block copolymer, the composition ratio of the polymer block (A) measured by ¹ H-NMR, and the composition ratio of the polymer block (A) and the acrylic polymer block (B) in the block copolymer. Is shown in Table 3.

The SP values of the polymer block (A) and the acrylic polymer block (B) are measured by ¹ H-NMR measurement, and the composition ratio of the polymer block (A) and the composition ratio of the acrylic polymer block (B) are determined. It was calculated from the above-mentioned calculation formula (formula (1)) and shown in Table 3. Further, Tg of the polymer block (A) and the acrylic polymer block (B) was obtained based on the differential scanning calorimetry of the block copolymers 1 to 4, and is shown in Table 3.

Examples 1 to 10 and Comparative Examples 1 to 4 (Examples 7 and 8 are reference examples)
The raw material components were put into a mixer with the formulations (mass ratio) shown in Tables 4 and 5, and were dry-blended.

Details of the raw material components other than block copolymers 1 to 4 are as follows.

〔Thermoplastic resin〕
Hard acrylic resin with acrylic rubber: PMMA (polymethyl methacrylate) + acrylic rubber, Parapet SA-1000NP (manufactured by Kuraray Co., Ltd.)
Soft acrylic resin: MMA (methyl methacrylate) / BA (butyl acrylate) block copolymer, Clarity LA2140e (manufactured by Kuraray Co., Ltd.)
Heat-resistant polyester elastomer: Perprene S-1002 (manufactured by Toyo Spinning Co., Ltd.)
[Conductivity imparting agent]
Ketjen Black: Ketjen Black EC600JD (manufactured by Lion), DBP oil absorption: 495 ml / 100 g, D ₅₀ : 1.5 μm (secondary particle size), BET specific surface area: 1270 m ² / g
Pitch-based carbon fiber: Dialead KM223HM N8500N0100 (manufactured by Mitsubishi Resin Co., Ltd.), average fiber length: 50 to 200 μm, fiber diameter: 10 μm, water absorption: 0.4% by mass
Ion conductive polymer: Sanconol TBX-8310 (manufactured by Sanko Chemical Industry Co., Ltd.), ethylene oxide-propylene oxide-allyl glycidyl ether copolymer, lithium fluoromethanesulfonate (CF ₃ SO ₃ Li) and adipate ester Mixture, lithium salt content: 10% by mass
[Crosslinking agent]
Cheminox AC-6 (Hexamethylenediamine Carbamate, manufactured by Unimatex)
[Dispersant]
SM1000 (Sakai Chemical Industry Co., Ltd., magnesium stearate metal soap)
〔Antioxidant〕
Ilganox B225 (manufactured by BASF)

Then, the obtained mixture was melt-kneaded with an extruder (continuous kneader) under the following conditions to produce pellets of a thermoplastic composition.
[Melting and kneading conditions]
Extruder: KZW32TW-60MG-NH (manufactured by Technobel Co., Ltd.)
Cylinder temperature: 180-260 ° C
Screw rotation speed: 200 to 650 r / min

The flexibility, heat resistance, and conductivity of the obtained thermoplastic elastomer composition were evaluated by the following methods. The results are shown in Tables 4 and 5.

[Flexibility and heat resistance]
A test piece with a thickness of 2 mm and a width of 12 mm formed by hot pressing is set in ARES G-2 manufactured by TA Instruments, and the temperature rise rate is 5 ° C / min in torsion mode (torsion) between lengths of 25 mm. The viscoelasticity was measured at 30 Hz from -60 ° C to 200 ° C, and the storage elastic modulus G'at 23 ° C and 150 ° C was measured. The smaller the storage elastic modulus G'at 23 ° C., the better the flexibility, and the larger the storage elastic modulus G'at 150 ° C., the better the heat resistance.

〔Conductivity〕
A test piece with a thickness of 2 mm, a width of 50 mm, and a length of 80 mm formed by hot pressing using a Lorester GP resistivity meter manufactured by Mitsubishi Chemical Analytech Co., Ltd. is resisted at 5 points by a four-probe method based on JIS K7194. The rate was measured and the volume resistivity was calculated. The smaller the volume resistivity, the higher the conductivity of the molded product.

From the above results, it can be seen that the thermoplastic elastomer compositions of Examples 1 to 10 have a good balance of flexibility, heat resistance, and conductivity as compared with Comparative Examples 1 to 4.

Further, for the thermoplastic elastomer compositions of Examples 1 and 5, the compression set and the A hardness were measured by the following methods. The results are shown in Table 6.

<Measurement of compression set>
A film sample having a thickness of 2 mm was prepared according to the sample preparation procedure for the initial tensile characteristics, and a disk-shaped molded body prepared by stacking seven pieces cut into a disk shape having a diameter of 29 mm was hot-pressed at 200 ° C. to make the thickness. A test piece adjusted to 12.5 mm ± 0.5 mm was used as a test piece, and the measurement was performed by a compression set according to JIS K 6262.
Specifically, at the standard temperature (23.2 ± 2 ° C.), the diameter and thickness of the test piece are 29.0 ± 0.5 mm (diameter) and 12.5 mm ± 0.5 mm (thickness), respectively. The test piece was sandwiched between compression plates equipped with spacers having a thickness of 9.3 to 9.4 mm. Under the condition that the ratio of compressing the test piece was 25% by volume, the thickness of the central part of the test piece was measured after holding at 70 ° C. for 24 hours, removing the compression plate at 23 ° C. and leaving it for 30 minutes.
The measurement result was applied to the following compression set calculation formula to calculate the value of compression set (%).
Compressive permanent strain (%) = (t ₀ −t ₂ ) / (t ₀ −t ₁ ) × 100
(In the formula, t ₀ is the original thickness of the test piece (mm), t ₁ is the thickness of the spacer (mm), and t ₂ is the thickness of the test piece 30 minutes after removal from the compressor (mm). Show)
The value of the compression set when the test piece completely returns to the dimensional shape before compression after compression release is 0%, and the dimensional shape does not return to the original shape even after being released from compression. Since the value of the compression set in the case is 100%, the smaller the value of the compression set is between 0% and 100%, the better the recovery.

<A hardness>
A film having a thickness of 2 mm produced in the same procedure as the compression set was allowed to stand in a constant temperature and humidity chamber (temperature 23 ° C., relative humidity 50%) for 24 hours or more to stabilize the state, and then three sheets were placed. Overlapping, the A hardness was measured according to JIS K 7215 "Plastic Durometer Hardness Test Method".

From the above results, in general, the compression set tends to decrease as the hardness increases, whereas when the block copolymer is crosslinked, the hardness is almost the same, though. It can be seen that the compression set is greatly improved.

The thermoplastic elastomer composition of the present invention is suitably used as a wide range of industrial materials that require conductivity, such as antistatic mats, antistatic grips, electromagnetic wave suppression sheets, cable coatings, and styluses.

Claims (5)

A thermoplastic elastomer composed of a polymer block (A) containing a structural unit derived from styrenes and a maleimide compound, and a block copolymer having an acrylic polymer block (B), and 100 parts by volume of the thermoplastic elastomer. A thermoplastic elastomer composition containing 1 to 100 parts by volume of a conductivity-imparting agent, wherein the polymer block (A) is derived from a maleimide compound in all the structural units of the polymer block (A). has a structural unit 30 mass% to 99 mass%, and a glass transition temperature (Tg) of Ri polymer der above 0.99 ° C., the block copolymer, polymer block (a) - (acrylic Polymer block (B) -polymer block (A)) It has an n-type structure (n is an integer of 1 to 10), and the conductivity-imparting agent is derived from acetylene black, furnace black, and ketjen black. comprising Ru at least one conductive carbon black der selected from the group, the thermoplastic elastomer composition. 30Hz dynamic viscoelasticity measurement by storage modulus, or less 1 × ¹⁰ 9 Pa at 23 ° C., and is 1 × ¹⁰ 7 Pa or higher at 0.99 ° C., claim 1 Symbol placement thermoplastic elastomer composition. The thermoplastic elastomer composition according to claim 1 or 2 , wherein at least one of the polymer block (A) and the acrylic polymer block (B) has a crosslinkable functional group. The thermoplastic elastomer composition according to any one of claims 1 to 3 , wherein the conductivity-imparting agent is an inorganic conductive filler having a volume median particle diameter of 0.1 to 500 μm by image analysis based on electron microscope observation. A molded product obtained by heat-molding the thermoplastic elastomer composition according to any one of claims 1 to 4 .