JP2021113300A - Block copolymer, production method thereof, and use of block copolymer - Google Patents

Abstract

To provide a block copolymer useful for an elastomer excellent in thermal resistance, moldability, flexibility, and compression set.SOLUTION: A block copolymer has a block structure composed of following polymer block (A)/polymer block (B)/polymer block (C). Polymer block (A): a polymer block having a glass transformation temperature (Tg) of 150°C or higher and containing a structural unit derived from styrene-based compounds and a maleimide compound, Polymer block (B): a polymer block having a Tg of 20°C or lower and containing an acrylic structural unit, Polymer block (C): a polymer block having a Tg of 150°C or higher and containing a vinyl structural unit and/or (meth)acrylic structural unit (where, the polymer block (C) has a different composition from the polymer block (A).)SELECTED DRAWING: None

Description

The present invention relates to a block copolymer, a method for producing the block copolymer, and the use of the block copolymer.

Examples of sealing materials widely used industrially include various elastomers such as nitrile rubber, acrylic rubber, silicone rubber, fluororubber and ethylene tetrafluoride resin (PTFE). Among these, acrylic rubber is a rubber-like elastic body mainly composed of acrylic acid ester and has excellent heat resistance. Therefore, packing and sealing materials for automobiles, various hose materials, and adhesives that require heat resistance are required. , Widely used as a material for coating materials and the like.

In particular, in automobile applications, in recent years, in vehicles such as automobiles, the number of places where soundproofing materials are installed has increased for the purpose of improving quietness as the engine output increases, and as a result, the temperature inside the engine room becomes high. There is a tendency. For this reason, members such as O-rings and gaskets used around the engine room are required to have an elastomer material having a small compression set and excellent heat resistance.

Examples of the elastomer composition having excellent heat resistance include an epoxy group-containing acrylic rubber (component (A)), a thermoplastic polyester resin (component (B)), and an olefin-based polymer segment and a vinyl-based copolymer segment. A composition comprising a specific graft copolymer composed of or a precursor thereof (component (C)), which is obtained by cross-linking the component (A), is disclosed (Patent Document). 1).

Further, as an elastomer composition having excellent heat resistance, moldability and compression set, for example, a thermoplastic polymer containing a polyester elastomer as a main component and a rubber component containing an acrylonitrile-butadiene copolymer as a main component have an average dispersed particle size 2 A thermoplastic elastomer composition dispersed in a size of 0.0 μm or less is disclosed (Patent Document 2). Furthermore, a block copolymer having a specific polymer block (A) containing a structural unit derived from styrenes and a maleimide compound and a specific acrylic polymer block (B) is disclosed (Patent). Document 3). Patent Document 3 also specifically discloses an elastomer composition containing a block copolymer in which the polymer block (A) has a crosslinkable functional group.

Japanese Unexamined Patent Publication No. 2007-45885 JP-A-2017-165810 International Publication No. 2017/073287

However, the elastomer disclosed in Patent Document 1 is not sufficiently satisfactory for applications requiring a high degree of heat resistance. Furthermore, there were concerns about moldability and compression set. Further, the elastomer disclosed in Patent Document 2 is excellent in heat resistance, moldability and compression set, while the shore D hardness specifically disclosed in the examples is about 30 (the value of the shore A hardness is 80). The value was large, and there was a problem in terms of flexibility. Further, the block copolymer described in Patent Document 3 exhibits high heat resistance and moldability, and exhibits excellent compression set because it is a crosslinked product, while it has a problem in terms of flexibility because it is a crosslinked product. It happened to be.

As described above, elastomers having excellent heat resistance, moldability, and compression set tend to have reduced flexibility. Therefore, so far, elastomers having excellent heat resistance, moldability, compression set, and flexibility have not been provided.

The present specification provides block copolymers and methods for producing them, which are useful for elastomers having excellent heat resistance, moldability, flexibility and compression set. The present specification also provides an elastomer composition containing such a block copolymer.

The present inventors have focused on the composition of a polymer block that functions as a hard segment and a polymer block that functions as a soft segment as a polymer that can contribute to heat resistance, moldability, flexibility, and compression set. As a result of various studies, it was found that the improvement of heat resistance, moldability, flexibility and compression set can be satisfied by adopting a block copolymer composition having a specific structure. Based on these findings, the present specification provides the following means.

[1] A block copolymer having a block structure composed of the following polymer block (A) / polymer block (B) / polymer block (C).
Polymer block (A): Glass transition temperature (Tg) is 150 ° C. or higher, and polymer block containing structural units derived from styrenes and maleimide compounds Polymer block (B): Tg is 20 ° C. or lower. Polymer block containing an acrylic structural unit Polymer block (C): A polymer block having a Tg of 150 ° C. or higher and containing a vinyl structural unit and / or a (meth) acrylic structural unit (however, heavy). The composition is different from that of the coalesced block (A).)
[2] The polymer block (A) and the polymer block (C) with respect to 100 parts by mass of the total amount of the polymer block (A), the polymer block (B) and the polymer block (C). The block copolymer according to [1], wherein the total amount of) is 50 parts by mass or less.
[3] The block copolymer according to [1] or [2], wherein the number average molecular weight of the block copolymer is 10,000 to 500,000.
[4] The block copolymer according to any one of [1] to [3], wherein the polymer block (C) contains a structural unit derived from a nitrogen-containing monomer and / or a carboxyl group-containing monomer. ..
[5] The polymer block (A) and the polymer block (C) with respect to 100 parts by mass of the total amount of the polymer block (A), the polymer block (B) and the polymer block (C). The block copolymer according to any one of [1] to [4], wherein the total amount of) is 35 parts by mass or less.
[6] The block copolymer according to any one of [1] to [5], wherein the Tg of the polymer block (C) is different from the Tg of the polymer block (A).
[7] A method for producing a block copolymer having a structural unit consisting of the following polymer block (A) / polymer block (B) / polymer block (C) by a living radical polymerization method.
Polymer block (A): Glass transition temperature (Tg) is 150 ° C. or higher, and polymer block containing structural units derived from styrenes and maleimide compounds Polymer block (B): Tg is 20 ° C. or lower. Polymer block containing an acrylic structural unit Polymer block (C): A polymer block having a Tg of 150 ° C. or higher and containing a vinyl structural unit and / or a (meth) acrylic structural unit (however, the above-mentioned The composition is different from that of the polymer block (A).)
[8] An elastomer composition containing the block copolymer according to any one of [1] to [6].

The disclosure of the present specification relates to a block copolymer, a method for producing the same, and the use of the block copolymer. Because the block copolymer disclosed in the present specification (hereinafter, also simply referred to as the present block copolymer) has a block structure composed of specific polymer blocks (A), (B) and (C). It can contribute to the improvement of flexibility and compression set, as well as heat resistance and moldability.

Although not binding on the disclosure of the present specification, the improvement of the characteristics of the present block copolymer, which is an ABC type triblock copolymer, will be described in comparison with the copolymer of the ABA type triblock structure. In the ABA type triblock copolymer, the polymer block (A) may be contained in the same domain, and as a result, it is known that a certain amount of loop chains are present in the polymer block (B). ing. On the other hand, according to the present block copolymer, both the polymer block (A) and the polymer block (C) are polymer blocks having a Tg of 150 ° C. or higher but not the same composition. Both blocks are incompatible. Therefore, it becomes difficult for the polymer block (A) and the polymer block (C) to aggregate to form the same domain, and the domain in which the polymer block (A) aggregates and the polymer block (C) are formed, respectively. It becomes easy to form an aggregated domain. As a result, the polymer block (B) tends to adopt a bridge structure between these domains. According to this block copolymer, due to the ease of forming such a bridge structure, excellent compression set and flexibility are maintained even if a bridge structure is not formed between the polymer blocks (A). Is presumed to be.

Hereinafter, various embodiments of the techniques disclosed in the present specification will be described in detail. In addition, in this specification, "(meth) acrylic" means acrylic and / or methacrylic, and "(meth) acrylate" means acrylate and / or methacrylate. Further, the “(meth) acryloyl group” means an acryloyl group and / or a methacryloyl group.

This block copolymer has a block structure composed of polymer blocks (A), (B) and (C). This block copolymer has one or more of these polymer blocks. When the block copolymer has two or more of the polymer block (A), the polymer block (B), and the polymer block (C), the two or more blocks are different even if they are the same. You may. That is, the monomer composition (type of monomer and its ratio) between blocks may be the same or different.

<Polymer block (A)>
The polymer block (A) has a glass transition temperature (Tg) of 150 ° C. or higher, and can contain structural units derived from styrenes and maleimide compounds. Hereinafter, the structural unit will be described first, and then Tg will be described.

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. 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 ratio of the structural units derived from the styrenes is preferably 1% by mass or more and 70% by mass or less with respect to all the 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 compounds include maleimide and N-substituted maleimide compounds. 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-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).

〔式中、Ｒ１は水素、炭素数１〜３のアルキル基又はＰｈＲ２を表す。ただし、Ｐｈはフェニル基を表し、Ｒ２は水素、ヒドロキシ基、炭素数１〜２のアルコキシ基、アセチル基又はハロゲンを表す。〕 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, R1 represents hydrogen, an alkyl group having 1 to 3 carbon atoms or PhR2. However, Ph represents a phenyl group, and R2 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 with respect to all the 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 units derived from the styrenes are insufficient, and as a result, the fluidity and moldability may be insufficient.

Further, the polymer block (A) can contain a crosslinkable functional group as long as the flexibility of the block copolymer is not impaired. A crosslinkable functional group is preferable because it is easy to obtain a block copolymer having a small compression set. 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.

Examples of unsaturated carboxylic acids include (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, cinnamic acid, and monoalkyl esters of unsaturated dicarboxylic acids (maleic acid, fumaric acid, and itacone). (Monoalkyl esters of acids, citraconic acid, maleic anhydride, itaconic anhydride, citraconic anhydride and the like) 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) butenyl 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 and 20 mol% or less based on the total structural units of the polymer block (A). Is. This is because if the amount of the crosslinkable functional group introduced is 0.01 mol% or more, it is effective in improving the compression set. On the other hand, if it exceeds 20 mol%, the flexibility of the block copolymer may be impaired.

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 disclosure are not impaired. good. 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 ratio of the structural units derived from the other monomers is in the range of 0% by mass or more and 50% by mass or less with respect to all the 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) acrylate 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, and n-butoxybutyl (meth) acrylate.

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.

In the present disclosure, the glass transition temperature (Tg) of the polymer constituting the polymer block (A) is preferably 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 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, further, for example, 260 ° C. or lower, for example, 250 ° C. or lower, or, for example. , 240 ° C. or lower, for example, 230 ° C. or lower, or 220 ° C. or lower, for example.

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.

<Polymer block (B)>
The polymer block (B) has a Tg of 20 ° C. or lower and can contain an acrylic structural unit derived from an acrylic monomer.

The 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-acrylic acid. 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 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. Further, from the viewpoint of heat resistance and oil resistance, the acrylic monomer contains an acrylic acid ester compound having an alkyl group having 1 to 3 carbon atoms or an alkoxyalkyl group having 2 to 3 carbon atoms. Is more preferable.

In the 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 with respect to all the structural units of the polymer block (B). It is preferably 50% by mass or more and 100% by mass or less, 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 polymer block (B), when the structural unit derived from the acrylic monomer is in the above range, a block copolymer having good mechanical properties tends to be obtained.

As long as the effects produced by the present disclosure are not impaired, the polymer block (B) can use a monomer other than the above-mentioned 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.

In the present disclosure, the Tg of the polymer constituting the polymer block (B) is preferably 20 ° C. or lower. Further, for example, the temperature may be 10 ° C. or lower. Tg is preferably 0 ° C. or lower, more preferably −10 ° C. or lower. Further, for example, the temperature may be −20 ° C. or lower, for example, −30 ° C. or lower, and for example, −40 ° C. or lower. If the Tg exceeds 20 ° C., the flexibility of the obtained block copolymer may be insufficient. Due to the limitation of the constituent monomer units that can be used, the lower limit of Tg is −80 ° C. 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, the polymer block (B) may contain a crosslinkable functional group as long as the flexibility of the present block copolymer is not impaired, and is preferable in that a block copolymer having high oil resistance can be easily obtained. 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 and 20 mol% or less based on the total structural units of the polymer block (B). Is. 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.

<Polymer block (C)>
The polymer block (C) is a block having a Tg of 150 ° C. or higher and having a structural unit composition different from that of the polymer block A. By having such a polymer block (C), it is possible to contribute to excellent heat resistance and moldability, as well as excellent flexibility and compression set.

The polymer block (C) has a Tg of 150 ° C. or higher, similar to the polymer block (A). On the other hand, the composition of the structural unit of the polymer block (C) is not the same as that of the polymer block (A). In this block copolymer, the composition of the structural units of the polymer blocks is not the same, which means that either the type of the structural units constituting the block or the ratio thereof is different. For example, the structural unit composition constituting the polymer block (C), that is, the case where the types of structural units are different and the cases where the types of structural units are the same but their ratios are different are included.

From the above, the polymer block (C) has a Tg of 150 ° C. or higher, for example, a structural unit derived from styrenes used in the polymer block (A), a structural unit derived from a maleimide compound, and a weight. Structural units derived from other monomers other than these that can be used in the coalesced block (A) can be provided. These structural units have already been described for the polymer block (A).

Considering that the polymer block (C) has a composition different from that of the polymer block (A) and the Tg is 150 ° C. or higher, for example, a structural unit derived from styrenes that can be used for the polymer block (A). And it is preferable to include a structural unit other than the structural unit derived from the maleimide compound.

(Vinyl-based structural unit)
The polymer block (C) can include a vinyl-based structural unit as the other structural unit. Here, the vinyl-based structural unit means a structural unit derived from a vinyl-based monomer that is not a structural unit derived from a monomer of a styrene or a maleimide compound.

Examples of such vinyl-based structural units include structural units derived from nitrogen-containing monomers. This is because by providing such a structural unit, it is easy to set Tg to 150 ° C. or higher with a structural unit composition different from that of the polymer block (A). The nitrogen-containing monomer is not particularly limited, but for example, the above-mentioned amide group-containing vinyl compounds, among them, (meth) acrylamide, and tert-butyl (meth) acrylamide, N, N- (Meta) acrylamide derivatives such as dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide and (meth) acryloylmorpholin; , N-vinylacetamide, N-vinylformamide, N-vinylisobutylamide and N-vinylamide-based monomers such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam. Further, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate and the like can be mentioned. Among them, tert-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide. And (meth) acrylamide derivatives selected from the group consisting of (meth) acryloylmorpholin can be used from the viewpoint of composition and Tg, and N-isopropyl (meth) acrylamide and (meth) acryloylmorpholin can be preferably used. ..

Further, as the vinyl-based structural unit included in the polymer block (C), for example, a structural unit derived from a carboxyl group-containing monomer can be mentioned. This is because by providing such a structural unit, it is easy to set Tg to 150 ° C. or higher with a structural unit composition different from that of the polymer block (A). Examples of the carboxyl group-containing monomer 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 and fumaric acid). , Itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, monoalkyl esters such as citraconic anhydride) and the like. Among these, (meth) acrylic acid such as acrylic acid can be used.

The structural units derived from these carboxyl group-containing monomers retain the carboxyl group when the functional group or compound crosslinked by the carboxyl group is not supplied to the block copolymer, but the functional group or compound is present. When supplied, it can form a crosslinked structure.

In the polymer block (C), the structural unit derived from the nitrogen-containing monomer is, for example, 1% by mass or more and 100% by mass or less with respect to all the structural units of the polymer block (C). Further, for example, it is 10% by mass or more and 100% by mass or less, and for example, 20% by mass or more and 100% by mass or less, and for example, 30% by mass or more and 100% by mass or less, and for example, 40% by mass or more and 100% by mass. It is mass% or less.

In the polymer block (C), the structural unit derived from the carboxy group-containing monomer is, for example, 1% by mass or more and 100% by mass or less with respect to all the structural units of the polymer block (C). Further, for example, it is 10% by mass or more and 100% by mass or less, and for example, 20% by mass or more and 100% by mass or less, and for example, 30% by mass or more and 100% by mass or less, and for example, 40% by mass or more and 100% by mass. It is mass% or less.

((Meta) acrylic structural unit)
The polymer block (C) may also include a (meth) acrylic structural unit as the other structural unit as described above, together with the vinyl structural unit or without the vinyl structural unit. Examples of the (meth) acrylic structural unit include structural units derived from the above-mentioned (meth) acrylic acid alkyl ester compound and (meth) acrylic acid alkoxyalkyl ester compound. Various aspects of the (meth) acrylic acid alkyl ester compound and the (meth) acrylic acid alkoxyalkyl ester compound have already been described for the polymer block (A).

The polymer block (C) is, for example, as a structural unit derived from a (meth) acrylic acid alkyl ester compound, (meth) acrylic acid cyclohexyl, (meth) acrylic acid methylcyclohexyl, (meth) acrylic acid tert-butylcyclohexyl, Alibos of (meth) acrylic acids such as cyclododecyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, etc. It is preferable to include a structural unit derived from a cyclic ester compound or the like.

In the polymer block (C), the (meth) acrylic structural unit is, for example, 1% by mass or more and 100% by mass or less with respect to all the structural units of the polymer block (C). Further, for example, it is 10% by mass or more and 90% by mass or less, and for example, 20% by mass or more and 80% by mass or less, and for example, 30% by mass or more and 70% by mass or less, and for example, 40% by mass or more and 70% by mass or less. It is mass% or less.

When the polymer block (C) includes the vinyl-based structural unit, it can simultaneously include the (meth) acrylic-based structural unit. In this case, the vinyl-based structural unit is not particularly limited, and examples thereof include structural units derived from nitrogen-containing monomers. Among them, tert-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide. And (meth) acrylamide derivatives selected from the group consisting of (meth) acryloylmorpholin can be used from the viewpoint of composition and Tg, and N-isopropyl (meth) acrylamide and (meth) acryloylmorpholin can be preferably used. ..

When the polymer block (C) includes (meth) acrylic structural units in addition to the vinyl-based structural units as described above, for all structural units of the polymer block (C), ( The meta) acrylic structural unit can be provided, for example, by 1% by mass or more and 80% by mass or less, and for example, 10% by mass or more and 70% by mass or less.

(Structural unit derived from styrenes and structural unit derived from maleimide compound)
In the polymer block (C), the structural unit derived from the styrenes provided in the polymer block (A) and / / in combination with the structural unit derived from the monomer suitable for the polymer block (C) described above. Alternatively, a structural unit derived from a maleimide compound can be provided. Considering incompatibility with the polymer block (A), the structural unit is, for example, 1% by mass or more and 80% by mass or less with respect to all the structural units of the polymer block (C), and for example. 1, 1% by mass or more and 70% by mass or less, and for example, 1% by mass or more and 60% by mass or less, and for example, 1% by mass or more and 50% by mass or less, and for example, 1% by mass or more and 40% by mass or less. It is, for example, 1% by mass or more and 30% by mass or less, and for example, 1% by mass or more and 20% by mass or less, and for example, 1% by mass or more and 10% by mass or less.

For example, when the polymer block (C) includes the vinyl-based structural unit, it can also include a structural unit derived from the maleimide compound. In this case, the vinyl-based structural unit is not particularly limited, and examples thereof include structural units derived from nitrogen-containing monomers such as amide group-containing vinyl compounds. Among them, tert-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide. And (meth) acrylamide derivatives selected from the group consisting of (meth) acryloylmorpholin can be used from the viewpoint of composition and Tg, and N-isopropyl (meth) acrylamide and (meth) acryloylmorpholin can be preferably used. ..

When the polymer block (C) includes, for example, a vinyl-based structural unit in addition to the vinyl-based structural unit as described above, it is derived from the maleimide compound with respect to all the structural units of the polymer block (C). The structural unit to be used can be provided, for example, by 35% by mass or more and 75% by mass or less, and for example, 45% by mass or more and 65% by mass or less.

Although not particularly limited, considering that the polymer block (A) and the polymer block (C) are incompatible, the structural unit derived from styrenes should be provided or not provided in an amount of less than 1% by mass. Can be. Further, for example, considering that the polymer block (A) and the polymer block (C) are incompatible, it is possible to include or not include structural units derived from the maleimide compound in an amount of less than 1% by mass. .. Further, from the same viewpoint, it is possible to prevent both the structural unit derived from styrenes and the structural unit derived from the maleimide compound.

Further, the polymer block (C) may contain a crosslinkable functional group as described in the polymer block (A) as long as the flexibility of the present block copolymer is not impaired. When the polymer block (C) has a crosslinkable functional group, the amount of the crosslinkable functional group introduced is preferably 0.01 mol% or more and 20 mol% or less based on the total structural units of the polymer block (C). Is. 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.

In the present disclosure, the glass transition temperature (Tg) of the polymer constituting the polymer block (C) is preferably 150 ° C. or higher. If the temperature is lower than 150 ° C., heat resistance and oil resistance may decrease. Tg is also, for example, 155 ° C. or higher, and, for example, 160 ° C. or higher, and also, for example. It is 165 ° C. or higher, and is, for example, 170 ° C. or higher, and is, for example, 180 ° C. or higher, and is, for example, 190 ° C. or higher. It may be 70 ° 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. 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, further, for example, 260 ° C. or lower, for example, 250 ° C. or lower, or, for example. , 240 ° C. or lower, for example, 230 ° C. or lower, or 220 ° C. or lower, for example.

Further, the Tg of the polymer block (C) may be different from the Tg of the polymer block (A). For example, when the polymer block (C) is mainly from the viewpoint of promoting the formation of the bridge chain of the polymer block (B), the polymer block (A) has the heat resistance of the block copolymer and the heat resistance of the block copolymer. Tg can be set at a higher temperature of the polymer block (A) so as to contribute to oil resistance, and Tg of the polymer block (C) can be set at a lower temperature than that of the polymer block (A). For example, the Tg of the polymer block (A) is 20 ° C. or higher, for example, 30 ° C. or higher, and for example, 40 ° C. or higher, and for example, 50 ° C. or higher, or 60 ° C. or higher, than the Tg of the polymer block (C). It can be set to a high temperature of ° C or higher.

<Block copolymer>
This block copolymer is an ABC-type triblock copolymer having one or more of the above-mentioned polymer block (A), polymer block (B), and polymer block (C).

In this block copolymer, the polymer block (A) and the polymer block (C) act as hard segments, and the polymer block (B) acts as soft segments. As a result, this block copolymer exhibits excellent mechanical properties such as breaking elongation and breaking strength, and becomes a useful material as an elastomer.

The polymer block (A) in this block copolymer is, for example, 5 parts by mass or more and 40 parts by mass with respect to a total of 100 parts by mass of the polymer block (A), the polymer block (B) and the polymer block (C). It is 10 parts by mass or less, for example, 10 parts by mass or more and 30 parts by mass or less, and for example, 10 parts by mass or more and 20 parts by mass or less. If it is less than 5 parts by mass, heat resistance and oil resistance may be lowered, and if it exceeds 40 parts by mass, flexibility may not be sufficient.

The ratio of the polymer block (B) in the block copolymer is, for example, 10 parts by mass or more and 90 parts by mass or less, and for example, 50 parts by mass or more and 90 parts by mass or less with respect to the total 100 parts by mass. Yes, for example, 50 parts by mass or more and 85 parts by mass or less, and for example, 50 parts by mass or more and 80 parts by mass or less. If it is less than 40 parts by mass, the flexibility may not be sufficient, and if it exceeds 90 parts by mass, the heat resistance may not be sufficient.

The ratio of the polymer block (C) in the block copolymer is, for example, 5 parts by mass or more and 40 parts by mass or less, and for example, 10 parts by mass or more and 30 parts by mass or less with respect to the total 100 parts by mass. Yes, and for example, it is 10 parts by mass or more and 20 parts by mass or less. If it is less than 5 parts by mass, the flexibility and compression set may not be improved, and if it exceeds 40 parts by mass, the flexibility may not be sufficient.

The total amount of the polymer block (A) and the polymer block (C) in the block copolymer is, for example, 50 parts by mass or less with respect to the total of 100 parts by mass. If it exceeds 50 parts by mass, the flexibility may not be sufficient. The total ratio is also, for example, 40 parts by mass or less, for example, 35 parts by mass or less, and for example, 30 parts by mass or less.

Further, when the polymer blocks (A) and the same (C) have a crosslinkable functional group, an elastomer material having a smaller value of compression set can be obtained by cross-linking using the crosslinkable functional groups. The cross-linking may be due to a reaction between the cross-linking functional groups introduced into the polymer blocks (A) and the same (C), or as described later, has a functional group capable of reacting with the cross-linking functional group. A cross-linking agent may be added. 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 this block copolymer is preferably in the range of 10,000 or more and 500,000 or less, for example. 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 also, for example, 20,000 or more and 400,000 or less, and for example, 50,000 or more and 300,000 or less, and for example, 50,000 or more and 200,000 or less, and 50,000. It is 100,000 or less.

The molecular weight distribution (Mw / Mn) obtained by dividing the weight average molecular weight (Mw) value of the block copolymer by the above number average molecular weight (Mn) value is 1.5 or less in terms of moldability. Is preferable. 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.

When the block copolymer has a crosslinkable functional group, it can have a crosslinked structure between the crosslinked functional groups and / or a crosslinked structure by a crosslinking agent. The cross-linking structure and the cross-linking agent that can be provided in this block copolymer will be described later.

<Manufacturing method of block copolymer>
This block copolymer is not particularly limited as long as a block copolymer having a polymer block (A), a polymer block (B) and a polymer block (C) can be obtained, and is not particularly limited, and is a known production method. Can be adopted. 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. Further, 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 zantate compound, a trithiocarbonate compound and a dithiocarbamate compound can be used.
The RAFT agent is preferably a monofunctional agent having only one active site. The amount of the RAFT agent used is appropriately adjusted depending on the monomer used, the type of 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 above 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.

｛式中、Ｒ１は炭素数１〜２のアルキル基又は水素原子であり、Ｒ２は炭素数１〜２のアルキル基又はニトリル基であり、Ｒ３は−（ＣＨ２）ｍ−、ｍは０〜２であり、Ｒ４、Ｒ５は炭素数１〜４のアルキル基である。｝ 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, R1 is an alkyl group or a hydrogen atom having 1 to 2 carbon atoms, R2 is an alkyl group or a nitrile group having 1 to 2 carbon atoms, R3 is − (CH2) m−, and m is 0 to 2. R4 and R5 are alkyl groups having 1 to 4 carbon atoms. }

The amount of the nitroxide compound used is appropriately adjusted depending on the monomer used, the type of the nitroxide compound, and the like.

｛式中、Ｒ４、Ｒ５は炭素数１〜４のアルキル基である。｝ When the block copolymer of the present disclosure is produced by the NMP method, 0.001 to 0.2 mol of the nitroxide radical represented by the general formula (3) is added to 1 mol of the nitroxide compound represented by the general formula (3). May be carried out by adding in the range of.

{In the formula, R4 and R5 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, if the reaction temperature is 140 ° C. or lower, side reactions such as radical chain transfer tend to be suppressed.

In the ATRP method, an organic halide is generally used as an initiator, and a transition metal complex is used as a catalyst to carry out a polymerization reaction. The organic halide used as the initiator is preferably monofunctional. Further, as the type of halogen, bromide and chloride are preferable.

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.

When an ABC triblock copolymer is obtained by the living radical polymerization method, for example, the target block copolymer may be obtained by sequentially polymerizing each block. In this case, first, as a first polymerization step, styrenes and a maleimide compound are 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 ABC triblock copolymer can be obtained by polymerizing a monomer containing the monomer of the polymer block (C). In this case, the polymerization initiator is preferably the above-mentioned monofunctional polymerization initiator.

In the present disclosure, the 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, 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, 1 -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 two or more of them can be used.

In the present disclosure, 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. Further, it may be carried out in a form such as bulk polymerization without using a polymerization solvent.

<Elastomer composition>
Although the block copolymer can be applied alone as an elastomer material, it may be in the form of a composition containing known additives or the like, if necessary. In particular, when the block copolymer contains a crosslinkable functional group in at least one of the polymer blocks, a crosslinker and a crosslink accelerator capable of reacting with the functional group are blended, and heat treatment or the like is performed as necessary. It is preferable to apply the mixture because it is possible to obtain an elastomer having a smaller value of permanent compression strain.

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 crosslinking agent.
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 ammonium salt of an organic carboxylic acid, a dithiocarbamate, a polyvalent carboxylic acid or an anhydride, and the like. 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 of the present disclosure 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 of the present disclosure 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 of the present disclosure contains a polymerizable unsaturated group, a dithiol compound such as 1,2-ethanedithiol, 1,4-butanethiol, 1,10-decanethiol, 1,4-benzenethiol, etc. Alternatively, an en-thiol reaction with a polyhydric thiol such as a trithiol compound such as ethane-1,1,1-trithiol or 1,3,5-benzenetrithiol can be utilized.

When the cross-linking group of the block copolymer of the present disclosure 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.

Other examples of the above-mentioned additives include plasticizers, oils, antioxidants, inorganic fillers, pigments, antioxidants, ultraviolet absorbers and the like. The blending amount of the additive is preferably 0% by mass or more and 10% by mass or less, more preferably 0% by mass or more and 5% by mass or less, and further preferably 0% by mass or more and 2 by mass with respect to the block copolymer. It is mass% or less.

A thermoplastic resin may be added for the purpose of adjusting the performance, processability, etc. of the elastomer composition containing the block copolymer of the present disclosure. Specific examples of the thermoactive resin include polyolefin resins such as polyethylene and polypropylene, styrene resins of polystyrene, vinyl resins such as polyvinyl chloride, polyester resins, and polyamide resins. Moreover, you may add and mix other elastomers.

The elastomer composition containing the block copolymer of the present disclosure exhibits good fluidity when heated to about 200 ° C. or higher and 250 ° C. or lower. Therefore, it can be applied to molding processes by various methods such as extrusion molding, injection molding, and casting molding.

The elastomer composition disclosed in the present specification has, for example, 8 MPa or more, for example, 9 MPa or more, and for example, when the tensile strength at break and the elongation at break are measured according to the method for evaluating the initial tensile properties disclosed in Examples. Breaking strength of 10 MPa or more, for example 15 MPa or more, and for example 20 MPa or more, and for example 300% or more, for example 400% or more, and for example 500% or more, for example 550% or more, and for example. It can be provided with a breaking elongation of 600% or more, for example 650% or more, for example 700% or more, and for example 750% or more.

The elastomer composition disclosed in the present specification has, for example, 80% or more when the heat aging property is measured according to the method for evaluating the heat aging property (breaking strength retention rate and breaking elongation retention rate) disclosed in Examples. Also, for example, a breaking strength retention rate of 85% or more, for example 90% or more, and for example 95% or more, and for example 80% or more, for example 85% or more, and for example 90% or more, and for example. , 95% or more, for example 98% or more, and for example 99% or more of the elongation at break retention rate can be provided.

When the moldability of the elastomer composition disclosed in the present specification is measured according to the moldability evaluation method disclosed in Examples, for example, 200 ° C. or higher and 250 ° C. or lower, 200 ° C. or higher and 240 ° C. or lower, 200 ° C. or higher. Melt of 0.1 g / 10 min or more at a heating temperature of 230 ° C. or lower, 200 ° C. or higher and 220 ° C. or lower, and a load of, for example, 1 kg or more and 6 kg or less, for example, 1 kg or more and 5 kg or less, and for example, 1 kg or more and 3 kg or less. The flow rate (MFR) value can be indicated.

Further, the elastomer composition disclosed in the present specification has, for example, 20 or more and 70 or less, and for example, 25 or more and 60 or less, when the shore A hardness is measured according to the shore A hardness evaluation method disclosed in Examples. Further, for example, a shore A hardness of 25 or more and 55 or less, for example, 25 or more and 50 or less, for example, 25 or more and 45 or less, and for example, 25 or more and 40 or less can be provided.

Further, the elastomer composition disclosed in the present specification has, for example, 30 or more and 60 or less, and for example, 35 or more and 50 or less, when the compression set is measured according to the compression set evaluation method disclosed in Examples. Further, for example, a compression set of 35 or more and 45 or less can be provided.

Hereinafter, the present disclosure will be specifically described based on Examples. The present disclosure is not limited to these examples. In the following, "parts" and "%" mean parts by mass and% by mass unless otherwise specified.

The analysis method of the polymer obtained in the production example and the comparative production example will be described below.

<Molecular weight measurement>
The obtained polymer was subjected to gel permeation chromatography (GPC) measurement under the conditions described below to obtain a number average molecular weight (Mn) and a weight average molecular weight (Mw) in terms of polystyrene. Moreover, the molecular weight distribution (Mw / Mn) was 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

<Composition ratio of polymer>
The composition ratio of the obtained polymer was identified and calculated by 1H-NMR measurement.

<Glass transition temperature (Tg)>
The glass transition temperature (Tg) of the obtained polymer was 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 was obtained under the condition that the temperature was raised to 350 ° C. in min.
Measuring equipment: DSC6220 manufactured by SII Nanotechnology Co., Ltd.
Measurement atmosphere: Under nitrogen atmosphere By measuring the differential scanning calorimetry of the block copolymers obtained in the production examples and comparative production examples, inflection points corresponding to each polymer block were obtained, and each weight was obtained from these. The Tg of the coalesced block can be obtained.

Next, the evaluation method of the elastomer in Examples and Comparative Examples will be described below.

<Initial tensile characteristics>
A solution having a polymer concentration of 10% was prepared by dissolving 100 parts of the block copolymer and 0.3 part of Irganox 1010 (manufactured by BASF), which is an antioxidant, in tetrahydrofuran (THF). This was poured into a mold and THF was dried and distilled off to prepare a cast film having a thickness of about 1 mm. Using the film obtained above as a sample, the tensile strength at break and the elongation at break under normal conditions (25 ° C.) were measured according to JIS K 6251.

<Heat-resistant aging>
A film having the same initial tensile characteristics was used as the sample.
The sample punched into a dumbbell shape was put into an explosion-proof dryer at 150 ° C., and the sample was taken out after 1000 hours had passed. Then, according to JIS K 6251, the tensile strength at break and the elongation at break under normal conditions (25 ° C.) were measured. The heat aging resistance was evaluated by calculating the breaking elongation and the holding rate of breaking strength with respect to the initial measured values.

<Moldability>
A block copolymer was used as a sample. The melt flow rate (MFR) measured according to ASTM D 1239 was evaluated based on the heating temperature and load conditions when a value of 0.1 g / 10 min or more was obtained. It was judged that the more the melt flow rate can be obtained under low temperature and low load conditions, the better the fluidity and the better the moldability.

<Shore A hardness>
A film having a thickness of 2 mm prepared according to the sample preparation procedure for the above initial tensile characteristics is 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 the sheet is placed. Three layers were stacked, and the shore A hardness was measured according to JIS K 7215 "Plastic Durometer Hardness Test Method".

<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 as specified in 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 (%) = (t0-t2) / (t0-t1) x 100
(In the formula, t0 indicates the original thickness (mm) of the test piece, t1 indicates the thickness of the spacer (mm), and t2 indicates the thickness (mm) of the test piece 30 minutes after removal from the compression device.)
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 if it is 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.

Production Example 1 (Production of Polymer A)
First polymerization step (polymer block (A))
2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid (hereinafter also referred to as "CBSTSP") (1.65 g), 2,2'-azobis 2 in a 2 L flask equipped with a stirrer and a thermometer. -Methylbutyronitrile (hereinafter also referred to as "ABN-E") (0.25 g), N-phenylmaleimide (hereinafter also referred to as "PhMI") (56.3 g), styrene (hereinafter also referred to as "St") (33) 8.8 g) and acetonitrile (179 g) were charged, sufficiently degassed by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70 ° C. After 3 hours, the reaction was stopped by cooling to room temperature. The polymerization rates of PhMI and St at this point were 97% and 98%, respectively. The molecular weights were Mn11,500, Mw13,600, and Mw / Mn1.18 as measured by GPC (in terms of polystyrene).

Second polymerization step (polymer block (B))
Subsequently, ethyl acrylate (hereinafter, also referred to as "EA") (36.5 g), butyl acrylate (hereinafter, also referred to as "BA") (228 g), and 2-methoxyethyl acrylate (hereinafter, "C-") were added to the above polymerization solution. 1 ”(also referred to as) (192 g) and acetonitrile (14.1 g) were charged, sufficiently degassed by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70 ° C. After 4 hours, acetonitrile (334 g) was charged, cooled to room temperature, and the reaction was stopped. The polymerization rates of EA, BA, and C-1 at this time were 92%, 91%, and 93%, respectively. The molecular weights were Mn72,900, Mw97,700, and Mw / Mn1.34 as measured by GPC (in terms of polystyrene).

Third polymerization step (polymer block (C))
Subsequently, acryloyl morpholine (hereinafter also referred to as “ACMO”) (91.7 g) and acetonitrile (40.8 g) were charged into the above-mentioned polymerization solution, sufficiently degassed by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70 ° C. .. After 8 hours, acetonitrile (392 g) was charged, cooled to room temperature, and the reaction was stopped. The polymerization rate of ACMO at this point was 95%. The obtained polymer solution was reprecipitated and purified from methanol / water = 90/10 (Vol%) and vacuum dried to obtain an ABC-type triblock copolymer (hereinafter, also referred to as "polymer A"). ..

Evaluation of composition ratio, Tg, molecular weight, initial physical properties (breaking strength and breaking elongation), heat aging resistance (breaking strength retention rate and breaking elongation retention rate), moldability, Shore A hardness and compressive permanent strain of polymer A was evaluated. went. The results of these evaluations are shown in Table 2.

Production Examples 2 to 9 and Comparative Production Examples 1 to 3 (Production of Polymers B to L)
Polymers B to L were obtained in the same manner as in Production Example 1 except that the types and amounts of the raw materials charged in the flask were changed as shown in Table 1 and the reaction time was appropriately adjusted. The evaluation results for the polymers B to L are shown in Table 2. The polymers B to J were ABC-type triblock copolymers, and the K and L were ABA-type triblock copolymers.

Details of the compounds shown in Table 1 are as follows.
PhMI: N-phenylmaleimide St: Styrene EA: Ethyl acrylate BA: n-Butyl acrylate C-1: 2-Methyl acrylate ACMO: Acryloylmorpholin AdMA: Adamanthyl methacrylate AA: NIPAM acrylate: N-isopropylacrylamide CBSTSP: 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoate ABN-E: 2,2'-azobis (2-methylbutylonitrile)

≪Evaluation result≫
As is clear from Table 2, all of Examples 1 to 9, which are elastomer compositions containing the present block copolymer, showed good values in both initial breaking elongation and breaking strength, and were excellent in moldability. Further, it was confirmed that excellent heat resistance (breaking strength retention rate and breaking elongation retention rate) was exhibited even under severe conditions of 150 ° C. and 1000 hours. Further, the hardness value is 70 at the maximum, 41 at the next, 29 at the minimum, and is about 30 or more and 40 or less. Since it is small as a whole, it is confirmed that it is excellent in flexibility and compression. The maximum permanent strain was 49, which was approximately 35 or more and 45 or less, which was confirmed to be excellent.

On the other hand, Comparative Example 1, which is an ABC-type triblock copolymer but has a Tg of both A block and C block of less than 150 ° C., is inferior in initial physical properties (breaking strength and breaking elongation) and has heat resistance. (Retention rate of breaking strength and holding rate of elongation at break) were significantly inferior. Further, in Comparative Examples 2 and 3 which are ABA type triblock copolymers having a Tg of A block of 150 ° C. or higher, the moldability is slightly lowered and the hardness exceeds 75 and the flexibility is remarkably lowered. In addition, it was found that the compression set also exceeded 90 and was significantly reduced.

Based on the above, an ABC-type triblock copolymer having an A block and a C block having a Tg of 150 ° C. or higher and a B block having a Tg of 20 ° C. or lower and having different structural unit compositions of the A block and the C block can be obtained. Therefore, it was found that an elastomer composition having initial strength and heat resistance and excellent flexibility, compression set, and moldability can be provided.

Claims (8)

A block copolymer having a block structure composed of the following polymer block (A) / polymer block (B) / polymer block (C).
Polymer block (A): Glass transition temperature (Tg) is 150 ° C. or higher, and polymer block containing structural units derived from styrenes and maleimide compounds Polymer block (B): Tg is 20 ° C. or lower. Polymer block containing an acrylic structural unit Polymer block (C): A polymer block having a Tg of 150 ° C. or higher and containing a vinyl structural unit and / or a (meth) acrylic structural unit (however, the above-mentioned The composition is different from that of the polymer block (A).) The total amount of the polymer block (A), the polymer block (B), and the polymer block (C) is 100 parts by mass, and the total amount of the polymer block (A) and the polymer block (C) is 100 parts by mass. The block copolymer according to claim 1, wherein the amount is 50 parts by mass or less. The block copolymer according to claim 1 or 2, wherein the block copolymer has a number average molecular weight of 10,000 to 500,000. The block copolymer according to any one of claims 1 to 3, wherein the polymer block (C) contains a structural unit derived from a nitrogen-containing monomer and / or a carboxyl group-containing monomer. The total amount of the polymer block (A), the polymer block (B), and the polymer block (C) is 100 parts by mass, and the total amount of the polymer block (A) and the polymer block (C) is 100 parts by mass. The block copolymer according to any one of claims 1 to 4, wherein the amount is 35 parts by mass or less. The block copolymer according to any one of claims 1 to 5, wherein the Tg of the polymer block (C) is different from the Tg of the polymer block (A). A method for producing a block copolymer having a structural unit consisting of the following polymer block (A) / polymer block (B) / polymer block (C) by a living radical polymerization method.
Polymer block (A): Glass transition temperature (Tg) is 150 ° C. or higher, and polymer block containing structural units derived from styrenes and maleimide compounds Polymer block (B): Tg is 20 ° C. or lower. Polymer block containing acrylic structural unit Polymer block (C): Polymer block containing vinyl-based structural unit and / or (meth) acrylic structural unit with Tg of 150 ° C. or higher (however, heavy weight). It is different from the united block (A).) An elastomer composition comprising the block copolymer according to any one of claims 1 to 6.