Block copolymer, resin composition, stretch conductor, electronic device, and pressure-sensitive adhesive film
A block copolymer consists mainly of structural units each derived from an ethylenically unsaturated monomer and has at least one mercapto group. The block copolymer has an Mn of 5,000-500,000 and has a block structure, which is an A-B-A triblock structure or a star-shaped block structure of [A-B]qX. The q is an integer of 2-6. The polymer block (A) has a glass transition temperature of 20° C. or higher. The polymer block (B) of the triblock structure has a glass transition temperature lower than 20° C., and the [polymer block (B)]qX of the star-shaped block structure has a glass transition temperature lower than 20° C. The X is an initiator residue or/and a coupling-agent residue or is a derivative thereof.
1 . A block copolymer mainly composed of a structural unit derived from an ethylenically unsaturated monomer, which has at least one mercapto group, a number average molecular weight of 5,000 to 500,000, wherein the block copolymer contains an organic iodine-based living radical polymerization initiator residue and has any structure of the following General Formulae (2) to (4), and the polymerization unit in the General Formulae (2) to (4) is a block structure that is a triblock structure of polymer block (A)-polymer block (B)-polymer block (A) or a star-shaped block structure of [polymer block (A)-polymer block (B)] q X,
wherein q represents an integer of 2 or more and 6 or less,
the glass transition temperature of the polymer block (A) is 20° C. or higher,
the glass transition temperature of the polymer block (B) in the case of the triblock structure and the glass transition temperature of [polymer block (B)] q X in the case of the star-shaped block structure are lower than 20° C., and
X represents an initiator residue and/or a coupling agent residue, or its derivatives,
where the polymerization unit is a polymer unit mainly composed of a structural unit derived from an ethylenically unsaturated monomer independently for each branch from Y in the case of General Formula (4),
Z 1 each independently represents a divalent group selected from the group consisting of an ester group, a ketone group and an amide group, or a direct bond for each branch from Y,
Q represents a monovalent molecular terminal group, and the molecular terminal group is a functional group, a hydrocarbon group which may have a functional group, or an iodine group independently for each branch from Y,
Y represents a p-valent hydrocarbon group which may have a substituent,
p represents an integer of 2 to 6,
R 2 , R 5 and R 6 each independently represent a hydrogen atom or a monovalent hydrocarbon group which may have a substituent independently for each branch from Y in the case of General Formula (4),
R 3 and R 7 each independently represent a hydrogen atom, a monovalent hydrocarbon group which may have a substituent or —COR 8 independently for each branch from Y in the case of General Formula (4),
R 4 represents a monovalent hydrocarbon group which may have a substituent, —COR 8 , a cyano group or a nitro group,
R 2 and R 3 , R 3 and R 4 , R 2 and R 4 and R 6 and R 7 each independently may be bonded to each other to form a ring independently for each branch from Y in the case of General Formula (4),
R 8 each independently represents a hydrogen atom, a hydroxy group, an alkoxy group, an amino group or a monovalent hydrocarbon group which may have a substituent,
R 11 represents a divalent hydrocarbon group, which may have a substituent,
R 12 represents a divalent hydrocarbon group selected from the group consisting of an alkylene group, an arylene group and an alkylene oxide group or a direct bond, and
the hydrocarbon group may have a heterocycle, and each independently include at least one of a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group.
2 . The block copolymer according to claim 1 ,
wherein at least some of the mercapto groups are introduced by a thiol-ene reaction between an alkenyl group of a precursor of the block copolymer and a compound represented by General Formula (1):
HS—R 1 —SH General Formula (1)
where R 1 each independently represents a divalent organic group having at least one selected from among an alkylene group, an arylene group, a heterocyclic group and an alkylene oxide group, which may have a substituent.
3 . The block copolymer according to claim 1 , which is obtained by a living radical polymerization method.
4 . The block copolymer according to claim 1 , wherein the polymer block (A) has a mercapto group, and the polymer block (B) does not have a mercapto group.
5 . The block copolymer according to claim 1 , wherein the mercapto group is introduced into at least a part of the molecular terminal.
6 . The block copolymer according to claim 1 , wherein the polymer block (A) contains 50 mass % or more of a structural unit derived from a methacrylic acid ester, and the polymer block (B) contains 70 mass % or more of a structural unit derived from an acrylic acid ester.
7 . The block copolymer according to claim 1 , wherein the polymer block (A) contains 50 mass % or more of a structural unit derived from methyl methacrylate and the polymer block (B) contains 70 mass % or more of a structural unit derived from butyl acrylate.
8 . The block copolymer according to claim 1 , wherein 90 mass % or more of the ethylenically unsaturated monomer is a hydrophobic ethylenically unsaturated monomer.
9 . The block copolymer according to claim 1 , wherein the degree of polydispersity (Mw/Mn) is 2.5 or less.
10 . The block copolymer according to claim 1 , wherein the content of the polymer block (A) with respect to the polymer block (A) and the polymer block (B) of the block copolymer is in a range of 1 to 50 mass %.
11 . The block copolymer according to claim 1 , wherein the molar concentration of the mercapto group contained in 1 g of the block copolymer is in a range of 0.00001 to 1.0 mmol/g.
12 . A resin composition containing the block copolymer according to claim 1 .
13 . The resin composition according to claim 12 , wherein the content of iodine with respect to the block copolymer is in a range of 0.0001 to 10,000 ppm (by mass).
14 . The resin composition according to claim 12 , which contains a cross-linking agent that is able to crosslink with the block copolymer.
15 . The resin composition according to claim 12 , further containing at least one conductive material selected from the group consisting of conductive fine particles and conductive nanowires.
16 . A stretch conductor formed of the resin composition according to claim 15 .
17 . An electronic device having the stretch conductor according to claim 16 .
18 . A pressure-sensitive adhesive film having an adhesive layer formed of the resin composition according to claim 12 .