JPWO2020149385A1 - Crosslinkable block copolymers and coating agents - Google Patents

Abstract

The present invention provides a crosslinkable block copolymer capable of forming a tough and tackless film, and a coating agent using the crosslinkable block copolymer. The crosslinkable block copolymer of the present invention contains a polymer block B and a polymer block A that contains a monomer unit that is bonded to each of both ends of the polymer block B and has crosslinkability, and is crosslinked. After that, when the attenuation curve obtained by the Solid echo method in 1H pulse NMR (20 MHz) at 40 ° C. was fitted to a two-component relaxation curve using the nonlinear minimum square method, the shorter spin-spin relaxation time T2 ( 1) is 18 to 35 μsec, and the component ratio A1 of the relaxation curve having the spin-spin relaxation time T2 (1) is 40 to 70%.

Description

The present invention relates to crosslinkable block copolymers and coating agents.

Since acrylic block copolymers are excellent in moldability and flexibility, they have been developed in the coating field and have been put into practical use (Patent Documents 1 and 2).

In recent years, there has been a demand for coating properties on moving parts of devices such as wearable devices and flexible displays, and coating agents are particularly required to have resistance to repeated flexibility and elasticity.

In order to meet these requirements, it is conceivable to form a tough film by chemical cross-linking.

Patent Document 1 has an A block having a structural unit derived from a vinyl monomer having a polycyclic aliphatic hydrocarbon group and a B block having a structural unit derived from a vinyl monomer, and the average of the A blocks. The glass transition temperature is 25 ° C. or higher, the average glass transition temperature of the B block is lower than the average glass transition temperature of the A block, and the average glass transition temperature of the A block and the average glass transition temperature of the B block Block copolymers having a difference of 50 ° C. or higher have been proposed.

Patent Document 2 describes both a methacrylic polymer block (a) made of methyl methacrylate (a) 45 to 67% by weight and a block made of butyl acrylate (b) 55 to 33% by weight. A film for coating a metal plate formed by molding a polymer (A) is disclosed.

WO2018 / 016407 Patent No. 4733858

However, the block copolymers disclosed in Patent Documents 1 and 2 have a problem that the film strength is low and also have an adhesive property, so that dust and dirt easily adhere to the block copolymer. It also has points.

The present invention provides a crosslinkable block copolymer capable of forming a tough and tackless film, and a coating agent using the crosslinkable block copolymer.

Crosslinkable block copolymers
Polymer block B and
The polymer block A containing a monomer unit bonded to each of both ends of the polymer block B and having crosslinkability is included.
After cross-linking, when the decay curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. is fitted with a two-component transition curve using the nonlinear least squares method, the shorter spin-spin relaxation is performed. The time T ₂ (1) is 18 to 35 μsec, and the component ratio A _{1 of the} transition curve having the spin-spin relaxation time T ₂ (1) is 40 to 70%.

The crosslinkable block copolymer is an ABA type crosslinkable block copolymer in which the polymer block A is bonded to both ends of the polymer block B.
The polymer block A contains a monomer unit having crosslinkability, and contains
After cross-linking the crosslinkable block copolymer, the decay curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. is fitted with a two-component relaxation curve using the nonlinear least squares method. The shorter spin-spin relaxation time T ₂ (1) is 18 to 35 μsec, and the component ratio A _{1 of the} relaxation curve having the spin-spin relaxation time T ₂ is 40 to 70%. To do.

[Crosslinkable block copolymer]
The crosslinkable block copolymer of the present invention is an ABA type triblock copolymer in which the polymer block A is bonded to both ends of the polymer block B.

The monomer constituting the polymer block A of the crosslinkable block copolymer is not particularly limited, and examples thereof include monomers capable of performing a polymerization reaction such as radical polymerization, cationic polymerization, and anion polymerization, and have an ethylenically unsaturated bond. The monomer having is preferable.

Among the monomers constituting the polymer block A, monomers other than the monomers having crosslinkability described later, that is, monomers having no crosslinkability (hereinafter, “monomers not containing crosslinkable groups” or “non-crosslinkable monomers” Examples thereof include vinyl-based monomers, (meth) acrylic-based monomers, (meth) acrylamide-based monomers, and the like, which are excellent in radical polymerization reactivity. Therefore, (meth) acrylic-based monomers and (Meta) acrylamide-based monomers are preferable. In addition, (meth) acrylic means acrylic or methacrylic.

Examples of vinyl-based monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, and 2,4-dimethyl. Styrene, pn-butyl styrene, pt-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene , P-methoxystyrene, p-phenylstyrene, p-chlorostyrene, styrene-based monomers such as 3,4-dichlorostyrene and the like. The vinyl-based monomer may be used alone or in combination of two or more.

Examples of the (meth) acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and sec-butyl (meth). ) Acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (Meta) acrylate, lauryl (meth) methacrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, 3,5,5- Examples thereof include acrylates such as trimethylcyclohexyl (meth) acrylate, phenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and adamantyl (meth) acrylate. The (meth) acrylate-based monomer is preferably (meth) acrylate because it improves the toughness and tacklessness of the film formed after cross-linking of the crosslinkable block copolymer, and isopornyl (meth) acrylate and butylcyclohexyl (meth). Acrylate is more preferable, isobornyl acrylate and 4-t-butylcyclohexyl (meth) acrylate are more preferable, and isobornyl acrylate and 4-t-butylcyclohexyl acrylate are more preferable. The (meth) acrylic monomer may be used alone or in combination of two or more. (Meta) acrylate means methacrylate or acrylate.

Examples of the (meth) acrylamide-based monomer include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-phenyl (meth) acrylamide, and N-benzyl. (Meta) acrylamide, N-isobornyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N-3,5,5-trimethylcyclohexyl (meth) acrylamide, N-dicyclopentanyl (meth) acrylamide, N-di Cyclopentenyl (meth) acrylamide, N-adamantyl (meth) acrylamide, N, N-diphenyl (meth) acrylamide, N- (meth) acryloylmorpholine and the like can be mentioned, with N- (meth) acryloylmorpholine being preferred and N. -Acrylamide morpholine is more preferred. The (meth) acrylamide-based monomer may be used alone or in combination of two or more.

The non-crosslinkable monomer unit constituting the polymer block A preferably contains a monomer unit having a saturated aliphatic ring structure, and is preferably an isobornyl (meth) acrylate unit, 4-t-butylcyclohexyl ( It preferably contains at least one monomer unit selected from the group consisting of meta) acrylate units and N- (meth) acryloylmorpholine units. When the non-crosslinkable monomer constituting the polymer block A contains a monomer unit having a saturated aliphatic ring structure, the toughness of the film formed after cross-linking of the cross-linkable block copolymer and the toughness of the film are formed. Tacklessness is improved. The saturated aliphatic ring structure refers to a structure having no aromaticity among carbon ring-type structures having a structure in which carbon atoms are cyclically bonded. The saturated aliphatic ring structure may contain heteroatoms such as nitrogen atoms and oxygen atoms.

Examples of the monomer having a saturated aliphatic ring structure include isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, 3,5,5-trimethylcyclohexyl (meth) acrylate, and di. Cyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, N-isobornyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N-3,5,5-trimethylcyclohexyl (meth) acrylamide, N-dicyclopenta Nyl (meth) acrylamide, N-adamantyl (meth) acrylamide, N- (meth) acryloylmorpholin and the like can be mentioned. The monomer having a saturated aliphatic ring structure may be used alone or in combination of two or more.

Among the monomer units constituting the polymer block A, the content of the monomer unit having no crosslinkability improves the toughness and tacklessness of the film formed after the crosslinkability of the crosslinkable block copolymer. 60% by mass or more is preferable, 90% by mass or more is more preferable, 95% by mass or more is more preferable, and 98% by mass or more is particularly preferable. Among the monomer units constituting the polymer block A, the content of the monomer unit having no crosslinkability improves the toughness of the film formed after cross-linking of the cross-linkable block copolymer, and thus is 99.9. It is preferably 99.8% by mass or less, more preferably 99.8% by mass or less, and particularly preferably 99.7% by mass or less.

Among the monomer units constituting the polymer block A, the content of the monomer unit having a saturated aliphatic ring structure improves the toughness and tacklessness of the film formed after cross-linking of the cross-linkable block copolymer. Therefore, 60% by mass or more is preferable, 90% by mass or more is more preferable, and 95% by mass or more is more preferable. Among the monomer units constituting the polymer block A, the content of the monomer unit having a saturated aliphatic ring structure improves the toughness of the film formed after cross-linking of the cross-linkable block copolymer, and thus is 99. 9.9% by mass or less is preferable, 99.8% by mass or less is more preferable, and 99.7% by mass or less is more preferable.

The polymer block A contains a monomer unit having crosslinkability. Since the polymer block A contains a monomer unit having a crosslinkability, the polymer block A and the polymer block B have different polarities from each other to express a layer-separated structure, and the polymer block A is expressed. By actively introducing a crosslinked structure into the polymer, the crosslinkable block copolymer forms a tough film after crosslinking.

A crosslinkable monomer (crosslinkable monomer) forms a chemical bond by crosslinking treatment such as irradiation with radiation such as ultraviolet rays and electron beams, heating, reaction with moisture (water), acid, base and / or crosslinking agent. A monomer having a crosslinkable group that can be crosslinked. As the crosslinkable monomer, a monomer having a crosslinkable group that can form a chemical bond by irradiation with radiation (radiocrosslinkable monomer) is preferable, and a crosslinkable monomer that forms a chemical bond by irradiation with ultraviolet rays can be crosslinked. A monomer having a sex group (ultraviolet crosslinkable monomer) is more preferable. “Crosslinkability” means that a chemical bond can be formed and crosslinked by a crosslinking treatment such as irradiation with radiation such as ultraviolet rays and electron beams, heating, reaction with moisture (water), acid, base and / or a crosslinking agent. Say that.

The crosslinkable group is not particularly limited, and for example, a hydroxyl group, a thiol group, a carboxyl group, a glycidyl group, an oxetanyl group, a trimethoxysilyl group, an isocyanate group, an amino group, a vinyl group, a (meth) acryloyl group and a benzophenone group. , Benzoin group, thioxanthone group and the like, preferably a glycidyl group, a benzophenone group, a benzoin group and a thioxanthone group, and more preferably a glycidyl group and a benzophenone group. In addition, (meth) acryloyl means methacryloyl or acryloyl. (Meta) acryloxy means methacryloxy or acryloxy. When the monomer constituting the polymer block A contains a crosslinkable monomer having a benzophenone group as a crosslinkable group, the film formed by cross-linking the crosslinkable block copolymer has better toughness and tacklessness. Has sex.

The monomer having crosslinkability is not particularly limited, and for example, 4-hydroxybutyl acrylate glycidyl ether, 4- (meth) acryloyloxybenzophenone, 4- [2-((meth) acryloyloxy) ethoxy] benzophenone, 4- (Meta) acryloyloxy-4'-methoxybenzophenone, 4- (meth) acryloyloxyethoxy-4'-methoxybenzophenone, 4- (meth) acryloyloxy-4'-bromobenzophenone, 4- (meth) acryloyloxyethoxy- Examples thereof include 4'-bromobenzophenone, and 4-hydroxybutyl acrylate glycidyl ether, 4- (meth) acryloyloxybenzophenone and 4- [2-((meth) acryloyloxy) ethoxy] benzophenone are preferable. The monomer having a crosslinkable group may be used alone or in combination of two or more. In addition, (meth) acryloyloxy means methacryloyloxy or acryloyloxy.

In the monomers constituting the polymer block A, the content of the monomer unit having crosslinkability is 40 mass because the toughness and tacklessness of the film formed after cross-linking of the crosslinkable block copolymer are improved. % Or less is preferable, 10% by mass or less is more preferable, 5% by mass or less is more preferable, and 2% by mass or less is particularly preferable. The content of the crosslinkable monomer unit in the monomers constituting the polymer block A is 0.1% by mass because the toughness of the film formed after the crosslinkability of the crosslinkable block copolymer is improved. The above is preferable, 0.2% by mass or more is more preferable, and 0.3% by mass or more is particularly preferable.

The polymer block A is bonded to both ends of the polymer block B described later, and the crosslinkable block copolymer has an ABA type triblock structure. The two polymer blocks A bonded to both ends of the polymer block B do not have to be the same and may be different. That is, the two polymer blocks A bonded to both ends of the polymer block B may have the same or different types and contents of the monomer units constituting the two polymer blocks A. The molecular weights may be the same or different.

The molecular weight of the polymer constituting the polymer block A is preferably 2000 or more, more preferably 7,000 or more, and more preferably 10,000 or more. The molecular weight of the polymer constituting the polymer block A is preferably 100,000 or less, more preferably 80,000 or less, and even more preferably 30,000 or less. When the molecular weight of the polymer constituting the polymer block A is 2000 or more, the toughness of the film formed after cross-linking of the cross-linkable block copolymer is improved. When the molecular weight of the polymer constituting the polymer block A is 100,000 or less, the toughness of the film formed after cross-linking of the cross-linkable block copolymer is improved.

The ratio of the molecular weights of the two polymer blocks A bonded to both ends of the polymer block B is preferably 2.0 or less, more preferably 1.6 or less, and particularly preferably 1.2 or less. When the molecular weight ratio is within the above range, a layer-separated structure can be satisfactorily formed between the polymer block A and the polymer block B after the crosslinkable block copolymer is crosslinked, and the crosslinkable block can be formed. The toughness of the film formed after cross-linking of the copolymer is improved. The molecular weight ratio refers to a value obtained by dividing a large molecular weight by a small molecular weight among the molecular weights of the two polymer blocks A and A.

In the present invention, the molecular weight of the polymer constituting the polymer block A is determined from the peak top molecular weight of the polymer block A partial polymer and the peak top molecular weight of the crosslinkable block copolymer. Polymer block B The value obtained by subtracting the peak top molecular weight of the partial polymer.

The monomer constituting the polymer block B of the crosslinkable block copolymer preferably has no crosslinkability (non-crosslinkability). That is, the monomer constituting the polymer block B of the crosslinkable block copolymer is preferably a monomer having no crosslinkable group (hereinafter, may be referred to as “non-crosslinkable monomer”). If the monomer constituting the polymer block B does not have crosslinkability, the toughness of the film formed after cross-linking of the crosslinkable block copolymer is improved.

The monomer constituting the polymer block B of the crosslinkable block copolymer is not particularly limited, and examples thereof include monomers capable of performing a polymerization reaction such as radical polymerization, cationic polymerization, and anion polymerization, and have an ethylenically unsaturated bond. The monomer having is preferable.

Examples of the monomers constituting the polymer block B include vinyl-based monomers, (meth) acrylic-based monomers, and (meth) acrylamide-based monomers, which are excellent in radical polymerization reactivity, and thus (meth). Acrylic monomers and (meth) acrylamide monomers are preferred. In addition, (meth) acrylic means acrylic or methacrylic.

Examples of vinyl-based monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, and 2,4-dimethyl. Styrene, pn-butyl styrene, pt-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene , P-methoxystyrene, p-phenylstyrene, p-chlorostyrene, styrene-based monomers such as 3,4-dichlorostyrene and the like. The vinyl-based monomer may be used alone or in combination of two or more.

Examples of the (meth) acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and sec-butyl (meth). ) Acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (Meta) acrylate, lauryl (meth) methacrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, 3,5,5-trimethylcyclohexyl (meth) acrylate, phenyl ( Examples thereof include (meth) acrylates such as meta) acrylates, dicyclopentanyl (meth) acrylates, dicyclopentenyl (meth) acrylates and adamantyl (meth) acrylates, and (meth) acrylic acids, with (meth) acrylates being preferred. Alkyl (meth) acrylates are more preferred. The (meth) acrylic monomer may be used alone or in combination of two or more. The alkyl group of the alkyl (meth) acrylate preferably has 2 or more carbon atoms, and more preferably 4 or more carbon atoms. The alkyl group of the alkyl (meth) acrylate preferably has 12 or less carbon atoms, more preferably 10 or less carbon atoms, and more preferably 8 or less carbon atoms. When the number of carbon atoms of the alkyl group is 2 or more, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved. When the number of carbon atoms of the alkyl group is 12 or less, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved.

Examples of the (meth) acrylamide-based monomer include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-phenyl (meth) acrylamide, and N-benzyl. (Meta) acrylamide, N-isobornyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N-3,5,5-trimethylcyclohexyl (meth) acrylamide, N-dicyclopentanyl (meth) acrylamide, N-di Cyclopentenyl (meth) acrylamide, N-adamantyl (meth) acrylamide, N, N-diphenyl (meth) acrylamide, N- (meth) acryloylmorpholine and the like can be mentioned, with N- (meth) acryloylmorpholine being preferred and N. -Acrylamide morpholine is more preferred. The (meth) acrylamide-based monomer may be used alone or in combination of two or more.

The monomer constituting the polymer block B and the monomer constituting the polymer block A having no crosslinkability may be the same or different.

The molecular weight of the polymer constituting the polymer block B is preferably 5000 or more, more preferably 20000 or more, and more preferably 30,000 or more. The molecular weight of the polymer constituting the polymer block B is preferably 300,000 or less, more preferably 240000 or less, and particularly preferably 140000 or less. When the molecular weight of the polymer constituting the polymer block B is 5000 or more, the toughness of the film formed after cross-linking of the cross-linkable block copolymer is improved. When the molecular weight of the polymer constituting the polymer block A is 300,000 or less, the toughness of the film formed after cross-linking of the cross-linkable block copolymer is improved.

In the present invention, the molecular weight of the polymer constituting the polymer block B refers to a value calculated as follows. In the case of a crosslinkable block copolymer polymerized using a compound having one structure capable of activating living polymerization (for example, an exchange chain reaction site) per molecule, the polymer constituting the polymer block B The molecular weight of is the value obtained by subtracting the peak top molecular weight of the polymer block A partial polymer from the peak top molecular weight of the polymer block A-polymer block B partial polymer. In the case of a crosslinkable block copolymer polymerized using a compound having two structures (for example, exchange chain reaction sites) that can activate living polymerization per molecule, the polymer constituting the polymer block B The molecular weight of is the value obtained by subtracting the peak top molecular weight of the polymer block A partial polymer from the peak top molecular weight of the crosslinkable block copolymer.

In the crosslinkable block copolymer, the total content of the polymer block A is preferably 31% by mass or more, more preferably 33% by mass or more, and more preferably 35% by mass or more. When the total content of the polymer block A is within the above range, the toughness of the film formed after cross-linking of the cross-linkable block copolymer is improved.

In the crosslinkable block copolymer, the total content of the polymer block A is preferably 59% by mass or less, more preferably 57% by mass or less, and particularly preferably 55% by mass or less. When the total content of the polymer block A is within the above range, the toughness of the film formed after cross-linking of the cross-linkable block copolymer is improved.

In the crosslinkable block copolymer, the content of the polymer block B is preferably 41% by mass or more, more preferably 43% by mass or more, and more preferably 45% by mass or more. When the content of the polymer block B is within the above range, the toughness of the film formed after cross-linking of the cross-linkable block copolymer is improved.

In the crosslinkable block copolymer, the content of the polymer block B is preferably 69% by mass or less, more preferably 67% by mass or less, and particularly preferably 65% by mass or less. When the content of the polymer block B is within the above range, the toughness of the film formed after cross-linking of the cross-linkable block copolymer is improved.

In the crosslinkable block copolymer, the ratio of the molecular weight of the polymer block A to the molecular weight of the polymer block B (molecular weight of the polymer block A / molecular weight of the polymer block B) is preferably 0.10 or more. 15 or more is more preferable, and 0.20 or more is particularly preferable. In the crosslinkable block copolymer, the ratio of the molecular weight of the polymer block A to the molecular weight of the polymer block B (molecular weight of the polymer block A / molecular weight of the polymer block B) is preferably 0.60 or less. 50 or less is more preferable, and 0.35 or less is particularly preferable. When the ratio of the molecular weight of the polymer block A to the molecular weight of the polymer block B is 0.10 or more, the toughness and tacklessness of the film formed after cross-linking of the cross-linkable block copolymer is improved. When the ratio of the molecular weight of the polymer block A to the molecular weight of the polymer block B is 0.60 or less, the toughness of the film formed after cross-linking of the cross-linkable block copolymer is improved. The weight average molecular weight of the polymer block A refers to the arithmetic mean value of the molecular weights of the polymer block A bonded to both ends of the polymer block B.

The weight average molecular weight (Mw) of the crosslinkable block copolymer is preferably 10,000 or more, more preferably 40,000 or more, more preferably 45,000 or more, and even more preferably 50,000 or more. The weight average molecular weight (Mw) of the crosslinkable block copolymer is preferably 500,000 or less, more preferably 400,000 or less, more preferably 300,000 or less, and even more preferably 200,000 or less. When the weight average molecular weight (Mw) is 10,000 or more, the film formed by cross-linking the crosslinkable block copolymer has more excellent toughness. When the weight average molecular weight (Mw) is 500,000 or less, the film formed by cross-linking the cross-linking block copolymer has more excellent tackless property.

The dispersity (weight average molecular weight Mw / number average molecular weight Mn) of the crosslinkable block copolymer is preferably 3.0 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less. When the dispersity is 3.0 or less, the film formed by cross-linking the crosslinkable block copolymer has more excellent toughness and tackless property.

The molecular weight, weight average molecular weight, and number average molecular weight of the polymers constituting the polymer block of the crosslinkable block copolymer are polystyrene-equivalent values measured by the GPC (gel permeation chromatography) method. .. Specifically, 0.01 g of the crosslinkable block copolymer is collected, the collected crosslinkable block copolymer is supplied to a test tube, and THF (tetrahexyl) is added to the test tube to add the crosslinkable block copolymer weight. The coalescence is diluted 500-fold and filtered to prepare a measurement sample.

Using this measurement sample, the molecular weight of the polymer constituting the polymer block of the crosslinkable block copolymer, and the weight average molecular weight Mw and the number average molecular weight Mn of the crosslinkable block copolymer are measured by the GPC method. can do.

The molecular weight of the polymer constituting the polymer block of the crosslinkable block copolymer, and the weight average molecular weight Mw and the number average molecular weight Mn of the crosslinkable block copolymer are determined by, for example, the following measuring apparatus and measurement conditions. Can be measured.
Measuring device Waters ACQUITY APC system Measuring conditions Column: Waters HSPgel (TM) HR MB-M
Mobile phase: Tetrahydrofuran used 0.5 mL / min
Detector: RI detector
Standard substance: polystyrene
SEC temperature: 40 ° C

In a crosslinkable block copolymer, the shorter spin is obtained when the attenuation curve obtained by the Solid echo method by ¹ H pulse NMR (20 MHz) at 40 ° C. is fitted to a two-component relaxation curve using the nonlinear least squares method. -The spin relaxation time T ₂ (1) (hereinafter, may be simply referred to as "relaxation time T ₂ (1)") is preferably 18 μs or more, and preferably 20 μs or more. In a crosslinkable block copolymer, the shorter spin when the attenuation curve obtained by the Solid echo method by ¹ H pulse NMR (20 MHz) at 40 ° C. is fitted to a two-component relaxation curve using the nonlinear least squares method. -The spin relaxation time T ₂ (1) is preferably 35 μsec or less, and preferably 30 μsec or less. When the spin-spin relaxation time T ₂ (1) is 18 μsec or more, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved. When the spin-spin relaxation time T ₂ (1) is 35 μsec or less, the toughness and tacklessness of the film formed by cross-linking the cross-linking block copolymer are improved.

In the crosslinkable block copolymer, of the relaxation times of the above two relaxation curves, the longer relaxation time T ₂ (2) (hereinafter, may be simply referred to as “relaxation time T ₂ (2)”) is 500 μs or more is preferable, and 600 μs or more is more preferable. In the crosslinkable block copolymer, the longer relaxation time T ₂ (2) of the two relaxation curves is preferably 1000 μs or less, more preferably 800 μs or less. When the spin-spin relaxation time T ₂ (2) is 500 μsec or more, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved. When the spin-spin relaxation time T ₂ (2) is 1000 μsec or less, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved.

In a block copolymer obtained by cross-linking a crosslinkable block copolymer, the attenuation curve obtained by the Solid echo method by ¹ H pulse NMR (20 MHz) at 40 ° C. is relaxed by two components using the nonlinear least squares method. When curve-fitted, the shorter spin-spin relaxation time T ₂ (1) is 18 μsec or more, preferably 20 μsec or more. In a block copolymer obtained by cross-linking a crosslinkable block copolymer, the attenuation curve obtained by the Solid echo method by ¹ H pulse NMR (20 MHz) at 40 ° C. is relaxed by two components using the nonlinear least squares method. When curve-fitted, the shorter spin-spin relaxation time T ₂ (1) is 35 μsec or less, preferably 30 μsec or less. When the spin-spin relaxation time T ₂ (1) is 18 μsec or more, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved. When the spin-spin relaxation time T ₂ (1) is 35 μsec or less, the toughness and tacklessness of the film formed by cross-linking the cross-linking block copolymer are improved.

In the block copolymer obtained by cross-linking the crosslinkable block copolymer, the longer spin-spin relaxation time T ₂ (2) of the spin-spin relaxation times of the above two relaxation curves is 500 μs. The above is preferable, and 600 μsec or more is more preferable. In the block copolymer obtained by cross-linking the crosslinkable block copolymer, the longer spin-spin relaxation time T ₂ (2) of the spin-spin relaxation times of the above two relaxation curves is 1000 μs. The following is preferable, and 800 μsec or less is more preferable. When the relaxation time T ₂ (2) is 500 μsec or more, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved. When the relaxation time T ₂ (2) is 1000 μsec or less, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved.

In the crosslinkable block copolymer before and after cross-linking, the rate of change of the relaxation time T ₂ (2) is preferably 12% or less, more preferably 10% or less, and particularly preferably 8% or less. When the rate of change of the relaxation time T ₂ (2) is 12% or less, the polymer block A of the crosslinkable block copolymer is more selectively crosslinked, and the crosslinkable block copolymer is crosslinked to form the polymer block A. The toughness of the film is improved.

The rate of change in the relaxation time T ₂ (2) of the crosslinkable block copolymer before and after cross-linking (hereinafter, may be simply referred to as “rate of change in T ₂ (2)”) is calculated based on the following formula. Value.
Rate of change (%) of T ₂ (2)
= 100 × (Spin-spin relaxation time of crosslinkable block copolymer (before cross-linking) T ₂ (2) -Spin-spin relaxation time of block copolymer after cross-linking of cross-linkable block copolymer T ₂ (2)) / Cross-linking Spin-spin relaxation time of sex block copolymer (before cross-linking) T ₂ (2)

Further, in the crosslinkable block copolymer, the spin-spin of the two-component transition curve obtained by fitting the decay curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. as described later. Of the transition times, the component ratio A ₁ of the transition curve having the shorter spin-spin relaxation time T ₂ (1) is 35% or more, preferably 38% or more, and more preferably 40% or more. Spin-spin relaxation time of the two-component transition curve obtained by fitting the decay curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. in the crosslinkable block copolymer as described later. Of these, the component ratio A ₁ of the transition curve having the shorter spin-spin relaxation time T ₂ (1) is preferably 65% or less, more preferably 60% or less, and even more preferably 55%. When the component ratio A ₁ is 35% or more, the toughness and tacklessness of the film formed by cross-linking the cross-linkable block copolymer is improved. When the component ratio A ₁ is 65% or less, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved.

Spin-spin relaxation time of the two-component transition curve obtained by fitting the decay curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. in the crosslinkable block copolymer as described later. Of these, the component ratio A ₂ of the transition curve having the longer spin-spin relaxation time T ₂ (2) is preferably 35% or more, more preferably 40% or more, and particularly preferably 45% or more. Spin-spin relaxation time of the two-component transition curve obtained by fitting the decay curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. in the crosslinkable block copolymer as described later. Of these, the component ratio A ₂ of the transition curve having the longer spin-spin relaxation time T ₂ (2) is preferably 65% or less, more preferably 62% or less, and particularly preferably 60% or less. When the component ratio A ₂ is 35% or more, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved. When the component ratio A ₂ is 65% or less, the toughness and tacklessness of the film formed by cross-linking the cross-linking block copolymer is improved.

Further, in a block copolymer obtained by cross-linking a crosslinkable block copolymer, it is obtained by fitting the attenuation curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. as described later. Of the spin-spin relaxation times of the _two- component relaxation curves, the component ratio A ₁ of the relaxation curve having the shorter spin-spin relaxation time T ₂ (1) is 40% or more, preferably 42% or more. , 44% or more is more preferable. In a block copolymer obtained by cross-linking a crosslinkable block copolymer, the decay curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. was fitted by fitting as described below. Of the spin-spin relaxation times of the component relaxation curves, the component ratio A ₁ of the relaxation curve having the shorter spin-spin relaxation time T ₂ (1) is 70% or less, preferably 65% or less, preferably 58. % Or less is more preferable. When the component ratio A ₁ is 40% or more, the toughness and tacklessness of the film formed by cross-linking the cross-linkable block copolymer is improved. When the component ratio A ₁ is 70% or less, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved.

In a block copolymer obtained by cross-linking a crosslinkable block copolymer, the decay curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. was fitted by fitting as described below. Of the spin-spin relaxation times of the component relaxation curves, the component ratio A ₂ of the relaxation curve having the longer spin-spin relaxation time T ₂ (2) is preferably 30% or more, more preferably 35% or more. 42% or more is more preferable. In a block copolymer obtained by cross-linking a crosslinkable block copolymer, the decay curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. was fitted by fitting as described below. Of the spin-spin relaxation times of the component relaxation curves, the component ratio A ₂ of the relaxation curve having the longer spin-spin relaxation time T ₂ (2) is preferably 60% or less, more preferably 58% or less. 56% or less is more preferable. When the component ratio A ₂ is 30% or more, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved. When the component ratio A ₂ is 60% or less, the toughness and tacklessness of the film formed by cross-linking the cross-linkable block copolymer is improved.

In the block copolymer obtained by cross-linking the crosslinkable block copolymer, the relaxation time T ₂ (1) and the component ratio A _{1 of the} relaxation curve having the relaxation time T ₂ (1) satisfy the above range. As a result, the hard component and the soft component are present in a predetermined ratio, and the block copolymer obtained by cross-linking the crosslinkable block copolymer exhibits a good layer-separated structure and the above-mentioned hard component. Since the block copolymer has an appropriate hardness, the block copolymer obtained by cross-linking the cross-linkable block copolymer forms a film having excellent toughness.

The crosslinkable block copolymer is an ABA type triblock copolymer, and the hard component is mainly composed of a polymer block having a high glass transition temperature among the polymer blocks A and B. , The soft component is mainly composed of a polymer block having a low glass transition temperature among the polymer blocks A and B.

The hard component is mainly composed of the polymer block A, the soft component is mainly composed of the polymer block B, and the crosslinked structure is positively introduced into the polymer block A to form a crosslinkable block copolymer. It is possible to satisfactorily form a layer-separated structure due to the polar difference between the polymer blocks A and B of the block copolymer obtained by cross-linking the cross-linkable block copolymer while imparting appropriate hardness. , The block copolymer obtained by cross-linking the cross-linkable block copolymer is preferable because it can form a film having excellent toughness.

By containing at least one of isobornyl (meth) acrylate and 4-t-butylcyclohexyl (meth) acrylate as the non-crosslinkable monomer constituting the polymer block A, the hard component is weighted at a high ratio. It can be composed of a coalesced block A, and the block copolymer obtained by cross-linking a crosslinkable block copolymer forms a film having more excellent toughness. By containing N- (meth) acryloylmorpholine as a non-crosslinkable monomer constituting the polymer block A, the block copolymer obtained by cross-linking the cross-linkable block copolymer has more excellent toughness. Form a film having.

A method for measuring the attenuation curve of a crosslinkable block copolymer at 40 ° C. by ¹ H pulse NMR (20 MHz), a method for fitting the obtained attenuation curve to a two-component relaxation curve using a nonlinear least squares method, and an relaxation curve. The method of determining the spin-spin relaxation time and the component ratio based on the above will be described.

^{1 Use an} H-pulse NMR measuring device. ^{1 The} H-pulse NMR measuring device irradiates all protons existing in the measurement sample with pulsed radio waves at a low frequency (several tens of MHz) by a permanent magnet to cause nuclear magnetic resonance, and the response (spin-spin relaxation time). ) Is a measuring device to observe.

Weigh about 0.2 g each of the crosslinkable block copolymer before cross-linking or the block copolymer after cross-linking on the bottom of the NMR tube, set it in a ¹ H pulse NMR measuring device, and measure under the following conditions. To obtain the decay curve. As the ¹ H pulse NMR measuring device, a measuring device commercially available from Bruker under the trade name “minispec mq20” can be used.

Frequency: 20MHz
Measurement temperature: 40 ° C
Measurement conditions: Solid-echo method scans: 64
Recycle delay: 1s
Detection Mode: Magnitude
acquisition scales: 3ms

The block copolymer after cross-linking is produced in the following manner. A crosslinkable block copolymer before cross-linking is coated on the release-treated polyethylene terephthalate sheet so as to have a thickness of 20 μm. Next, the crosslinkable block copolymer is crosslinked so that the gel fraction is 50 to 90% by mass to prepare a crosslinked block copolymer.

For example, the crosslinkable block copolymer is irradiated with ultraviolet rays under the conditions of a UV-C irradiation intensity of about 48 mW / cm ² and a UV-C integrated light amount of 100 mJ / cm ² using an ultraviolet irradiation device, and the crosslinkable block co-weight. The coalescence is crosslinked to produce a crosslinked block copolymer. As the ultraviolet irradiation device, for example, an ultraviolet irradiation device commercially available from Heleus (formerly Fusion UV Systems) under the trade name "Light Hammer 6" (using an H bulb) can be used. As the illuminometer, for example, an illuminometer commercially available from EIT Instrument Markets under the trade name "UV Power Pack II" can be used.

Next, the analysis software is used to decompose the decay curve of the pre-crosslinkable block copolymer or the post-crosslink block copolymer measured as described above into a two-component relaxation curve. The Weibull coefficient is set to 1 (exponential function) for both transition curves, and fitting is performed using the nonlinear least squares method. That is, the spin-spin relaxation time T ₂ and the component ratio A in the following formula are calculated. At that time, it is confirmed that the [err] of the [SSR / err] is 0 or 1 and that the data after the two-component fitting is sufficiently close to the measured attenuation curve. In addition, "^" means a power.
f (t) = A ₁ × exp {-1 / W (1) (t / T ₂ (1)) ^ W (1)} + A ₂ × exp {-1 / W (2) (t / T ₂ (t / T ₂ ) 2)) ^ W (2)}

The shorter spin-spin relaxation time of the spin-spin relaxation time is defined as the spin-spin relaxation time T ₂ (1), and the longer spin-spin relaxation time is defined as the spin-spin relaxation time T ₂ (2). Let A _{1 be} the component ratio of the transition curve having the spin-spin relaxation time T ₂ (1), and let A _{2 be} the component ratio of the transition curve having the spin-spin relaxation time T ₂ (2). Let W (1) and W (2) be the Weibull coefficients (both 1) of each transition curve. As the analysis software, analysis software commercially available from Bruker under the trade name "TD-NMR Analyzer" can be used.

In a crosslinkable block copolymer and a block copolymer after cross-linking thereof, the higher the glass transition temperature of the monomer constituting the polymer block that mainly forms a hard component, the shorter the spin-spin relaxation time T ₂ . can do. The lower the glass transition temperature of the monomer constituting the polymer block that mainly forms the hard component, the longer the spin-spin relaxation time T ₂ can be. The spin-spin relaxation time T ₂ can be shortened as the glass transition temperature of the monomer constituting the polymer block that mainly forms the soft component is increased. The lower the glass transition temperature of the monomer constituting the polymer block that mainly forms the soft component, the longer the spin-spin relaxation time T ₂ can be.

In the crosslinkable block copolymer and the block copolymer after cross-linking thereof, the component ratio A ₁ can be increased as the content of the polymer block mainly forming a hard component is increased. Enough to increase the content of the polymer block mainly formed a soft component, it is possible to lower the component ratio A _1.

In the crosslinkable block copolymer, the content of the non-crosslinkable monomer in the polymer block that mainly forms a hard component is preferably 30.0% by mass or more, more preferably 32.0% by mass or more, and 35. 0% by mass or more is more preferable, and 39.6% by mass or more is more preferable. In the crosslinkable block copolymer, the content of the non-crosslinkable monomer in the polymer block that mainly forms a hard component is preferably 59.6% by mass or less, more preferably 57.0% by mass or less, 55. It is more preferably 0% by mass or less, and more preferably 50.0% by mass or less. When the content of the non-crosslinkable monomer in the polymer block mainly forming the hard component is 30.0% by mass or more, the tackless property of the film formed by cross-linking the cross-linkable block copolymer is improved. To do. When the content of the non-crosslinkable monomer in the polymer block that mainly forms a hard component is 59.6% by mass or less, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved. To do.

In the crosslinkable block copolymer, the content of the non-crosslinkable monomer in the polymer block that mainly forms a soft component is preferably 40.4% by mass or more, more preferably 45.0% by mass or more, and 50. More preferably, it is 0% by mass or more. In the crosslinkable block copolymer, the content of the non-crosslinkable monomer in the polymer block that mainly forms a soft component is preferably 70.0% by mass or less, more preferably 65.0% by mass or less, and 60. More preferably, it is 0% by mass or less. When the content of the non-crosslinkable monomer in the polymer block that mainly forms a soft component is 40.4% by mass or more, the toughness of the film formed by cross-linking the cross-linkable block copolymer is improved. To do. When the content of the non-crosslinkable monomer in the polymer block mainly forming the soft component is 70.0% by mass or less, the tackless property of the film formed by cross-linking the cross-linkable block copolymer is improved. To do.

Next, a method for producing a crosslinkable block copolymer will be described. The crosslinkable block copolymer can be produced by using a general-purpose polymerization method, but it is preferably produced by using living polymerization.

Examples of the living radical polymerization include living radical polymerization, living cationic polymerization, and living anionic polymerization, but living radical polymerization is preferable from the viewpoint of high versatility and safety of the polymerization reaction.

Examples of the living radical polymerization method include iniferter polymerization, nitroxide-mediated polymerization (NMP), atom transfer radical addition polymerization using a transition metal catalyst (ATRP), reversible chain transfer polymerization using a dithioester compound (RAFT), and an organic tellurium compound. Examples thereof include polymerization (TERP), reversible transfer catalyst polymerization (RTC) catalyzed by an organic compound, and reversible coordination-mediated polymerization (RCMP).

In particular, reversible chain transfer polymerization (RAFT) has (1) high monomer versatility, (2) does not cause an extreme decrease in reactivity with oxygen and light, and (3) at extremely low or high temperatures. Since the reaction proceeds without it, it can be carried out in a simple polymerization reaction environment and has high productivity, (4) no toxic substances such as metals and halogens are used, and (5) a crosslinkable block having a sufficient molecular weight. It is preferable because a copolymer can be produced.

The dithioester compound used for carrying out reversible chain transfer polymerization (RAFT) is not particularly limited as long as it is a dithioester compound having exchange chain reactivity, for example, a dithiobenzoate compound, a trithiocarbonate compound, and the like. Examples thereof include dithiocarbamate compounds and xanthate compounds, and trithiocarbonate compounds are preferable.

The trithiocarbonate compound is not particularly limited, and is, for example, 2-[(dodecylsulfanylthiocarbonyl) sulfanyl] propanoic acid, 4-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid, 4-cyano. A trithiocarbonate compound having only one exchange chain reaction site such as -4-[(dodecylsulfanylthiocarbonyl) sulfanyl] pentanoic acid, 4-[(2-carboxyethyl sulfanylthiocarbonyl) sulfanyl] -4-cyanopentanoic acid. , S, S-dibenzyltrithiocarbonate, bis {4- [ethyl- (2-hydroxyethyl) carbamoyl] benzyl} trithiocarbonate, 1,4-bis {[(dodecylsulfanylthiocarbonyl) sulfanyl] methyl} benzene Examples thereof include trithiocarbonate compounds having two exchange chain reaction sites such as, and trithiocarbonate compounds having only one exchange chain reaction site are preferable, 2-[(dodecylsulfanylthiocarbonyl) sulfanyl] propanoic acid and 4- {[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid is more preferred, and 2-[(dodecylsulfanylthiocarbonyl) sulfanyl] propanoic acid is more preferred.

In the crosslinkable block copolymer produced by using the trithiocarbonate compound, the introduction position of the trithiocarbonate compound residue in the crosslinkable block copolymer is different due to the chemical structure of the trithiocarbonate compound. When the trithiocarbonate compound has only one exchange chain reaction site for one trithiocarbonate group, the trithiocarbonate compound residue is a polymer constituting a crosslinkable block copolymer. Introduced at the end of the block. On the other hand, when the trithiocarbonate compound has two exchange chain reaction sites for one trithiocarbonate group, the trithiocarbonate compound residue constitutes a crosslinkable block copolymer. Introduced inside the coalescing block. Then, in the crosslinkable block copolymer produced by reversible chain transfer polymerization (RAFT) using a trithiocarbonate compound having only one exchange chain reaction site, the trithiocarbonate compound residue is decomposed by heat or light. Even so, since the crosslinkable block copolymer structure itself is not decomposed, it is further excellent in thermal stability and ultraviolet crosslink reactivity.

As described above, the crosslinkable block copolymer is preferably produced by reversible chain transfer polymerization (RAFT) with a dithioester compound. Examples of the polymerization form of reversible chain transfer polymerization (RAFT) include bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization and the like, and solution polymerization is preferable. When the crosslinkable block copolymer is produced by solution polymerization, it is necessary to detreat the solvent in the system in order to use the crosslinkable block copolymer as a coating agent.

Multi-step polymerization is performed to produce a crosslinkable block copolymer. For example, when reversible chain transfer polymerization (RAFT) is performed using a dithioester compound having only one exchange chain reaction site, first, the monomer constituting the polymer block A is used as a dithioester compound (dithioester). It is sufficiently polymerized (in the presence of the compound) to obtain a polymer block A partial polymer (first stage polymerization). Next, the monomer constituting the polymer block B is supplied into the polymerization reaction system and sufficiently polymerized to obtain a polymer block A-polymer block B partial polymer (second-stage polymerization). Further, a monomer constituting the polymer block A is supplied into the polymerization reaction system and sufficiently polymerized, and the polymer block A is bonded to both ends of the polymer block B to form an ABA type triblock. A crosslinkable block copolymer which is a copolymer can be obtained.

Further, when reversible chain transfer polymerization (RAFT) is performed using a dithioester compound having two exchange chain reaction sites (particularly, it has only one dithioester structure such as S, S-dibenzyltrithiocarbonate). (When performing reversible chain transfer polymerization (RAFT) using a dithioester compound), the monomers constituting the polymer block A are sufficiently polymerized using a dithioester compound (in the presence of the dithioester compound). , Polymer block A partial polymer is obtained (first stage polymerization). Next, the monomer constituting the polymer block B is supplied into the polymerization reaction system and polymerized (second-stage polymerization) to form the polymer block B in the middle portion of the polymer block A partial polymer, and A A crosslinkable block copolymer, which is a −BA type triblock copolymer, can be obtained. When reversible chain transfer polymerization (RAFT) is performed using a dithioester compound having two dithioester structures such as 1,4-bis {[(dodecylsulfanylthiocarbonyl) sulfanyl] methyl} benzene, polymer block B The monomers constituting the above are sufficiently polymerized using a dithioester compound (in the presence of the dithioester compound) to obtain a polymer block B partial polymer (first-stage polymerization). Next, the monomers constituting the polymer block A are supplied into the polymerization reaction system and polymerized (second-stage polymerization) to form the polymer blocks A at both ends of the polymer block B partial polymer. A crosslinkable block copolymer, which is an ABA type triblock copolymer, can be obtained.

In the monomer used as a raw material for producing the polymer block A, the content of the monomer having no crosslinkability improves the toughness and tacklessness of the film formed after the crosslinkability of the crosslinkable block copolymer. , 60% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 98% by mass or more. In the monomer used as a raw material for producing the polymer block A, the content of the monomer having no crosslinkability improves the toughness of the film formed after the crosslinkable block copolymer is crosslinked. 9% by mass or less is preferable, 99.8% by mass or less is more preferable, and 99.7% by mass or less is particularly preferable.

In the monomer used as a raw material for producing the polymer block A, the content of the crosslinkable monomer improves the toughness and tacklessness of the film formed after the crosslinkable block copolymer is crosslinked. 40% by mass or less is preferable, 10% by mass or less is more preferable, 5% by mass or less is more preferable, and 2% by mass or less is particularly preferable. In the monomer used as a raw material for producing the polymer block A, the content of the crosslinkable monomer is 0.1 because the toughness of the film formed after the crosslinkability of the crosslinkable block copolymer is improved. Mass% or more is preferable, 0.2% by mass or more is more preferable, and 0.3% by mass or more is particularly preferable.

Crosslinkable block copolymers produced using dithioester compounds may have a coloration derived from their chemical structure and a unique odor derived from sulfur atoms. For the purpose of reducing or removing such coloring and odor, reduction or removal treatment of dithioester compound residues in the crosslinkable block copolymer, and residual dithioester mixed in the crosslinkable block copolymer. It is preferable to carry out a reduction or removal treatment of the compound. Treatment methods for reducing or removing dithioester compound residues or residual dithioester compounds include, for example, treatment with heat, treatment with ultraviolet rays, treatment with excess radical initiator, treatment with a nucleophilic reagent or reducing agent, and treatment with an oxidizing agent. , Treatment with a metal catalyst, treatment with a hetero Diels-Alder reaction with a diene compound, and the like. Even if the dithioester compound residue or the residual dithioester compound is reduced or removed by the above treatment, there is no change in the action and effect of the crosslinkable block copolymer.

The crosslinkable block copolymer can be suitably used as a coating agent by adding an additive such as a photoacid generator, if necessary.

When the crosslinkable block copolymer is subjected to a crosslinking treatment, the crosslinkable group of the monomer unit having a crosslinkability contained in the polymer block A forms a crosslinked structure, and the crosslinked structure is formed in the polymer block A. Is introduced. The block copolymer into which the crosslinked structure is introduced forms a film having excellent toughness and tacklessness.

The probe tack of the film obtained by cross-linking the crosslinkable block copolymer is preferably 3N or less, more preferably 2N or less, and particularly preferably 1N or less.

The probe tack of the film obtained by cross-linking the cross-linkable block copolymer refers to the value measured as follows.

First, a crosslinkable block copolymer solution is applied onto a polyethylene terephthalate film having a thickness of 50 μm so that the thickness of the crosslinkable block copolymer after solvent removal is 20 μm.

Crosslinkable block copolymers are crosslinked to form a film. Crosslinking of the crosslinkable block copolymer is adjusted so that the gel fraction of the obtained film is 50 to 90% by mass.

For example, when the crosslinkable monomer is a monomer having a crosslinkable group that forms a chemical bond by irradiation with ultraviolet rays (ultraviolet crosslinkable monomer), a UV-C irradiation intensity: about Ultraviolet rays (UV-C) are irradiated at 48 mW / cm ² and UV-C integrated light amount: 60 mJ / cm ² . As the ultraviolet irradiation device, for example, an ultraviolet irradiation device commercially available from Heleus (formerly Fusion UV Systems) under the trade name "Light Hammer 6" (using an H bulb) can be used. As the illuminometer, for example, an illuminometer commercially available from EIT Instrument Markets under the trade name "UV Power Pack II" can be used.

The obtained film is cut into a planar square shape having a side of 20 mm to prepare a test piece. Using a probe tack measuring device, the probe tack of the test piece is measured at any 10 points under the measurement conditions of a probe load of 20 g (100 g / cm ² ) and a contact time of 1 second. Of the 10 points of data, the maximum value, the second highest value, the second lowest value, and the minimum value were excluded, and the arithmetic mean value of the remaining 6 probe tacks was used as the probe tack (N) of the film. ).

The gel fraction of the film is a value measured according to the following procedure. Supply 0.2 g of the film to the glass bottle. 30 g of tetrahydrofuran was supplied to a glass bottle and left at room temperature for 24 hours to swell the block copolymer after cross-linking.

The swollen block copolymer after cross-linking was filtered through a 200-mesh wire mesh, and the block copolymer after cross-linking was dried together with the wire mesh in a constant temperature bath heated to 80 ° C. The mass Yg of the block copolymer after cross-linking after drying is measured, and the gel fraction is calculated according to the following procedure.
Gel fraction (mass%) = 100 x Y / 0.2

The coating agent may contain additives such as an ultraviolet polymerization initiator, a plasticizer, an antioxidant, a colorant, a flame retardant and an antistatic agent as long as the physical properties are not impaired.

The crosslinkable block copolymer of the present invention can form a film having excellent toughness and tacklessness by crosslinking.

It is a graph which showed the attenuation curve of the crosslinkable block copolymer obtained in Example 1, and the relaxation curve obtained by fitting this attenuation curve into a two-component relaxation curve.

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

(Examples 1 to 13 and Comparative Examples 1 to 4)
In a separable flask equipped with a stirrer, a cooling tube, a thermometer and a nitrogen gas inlet, isobornyl acrylate, N-acryloyl morpholine, 4-t-butylcyclohexyl acrylate and n-butyl acrylate as non-crosslinkable monomers were added. 4-acryloyloxybenzophenone, 4- [2- (acryloyloxy) ethoxy] benzophenone and 4-hydroxybutyl acrylate glycidyl ether as crosslinkable monomers, and 2-[(dodecylsulfanylthiocarbonyl) sulfanyl] propanoic acid as trithiocarbonate compounds. And 4-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid and ethyl acetate as a solvent were supplied in the amounts shown in Tables 1 and 2, respectively, and stirred to prepare a reaction solution.

After replacing the inside of the separable flask with nitrogen gas, the reaction solution was maintained at 60 ° C. using a water bath. Next, reversible chain transfer polymerization (RAFT) was started by supplying 2,2'-azobis (isobutyronitrile) as a polymerization initiator to the reaction solution in the separable flask in the amounts shown in Tables 1 and 2. did. The reaction solution was kept at 60 ° C. for 6 hours to obtain a polymer block A partial polymer. The peak top molecular weight and weight average molecular weight of the polymer block A partial polymer are shown in Tables 1 and 2.

Tables 1 and 2 show n-butyl acrylate and ethyl acrylate as non-crosslinkable monomers, 4-acryloyloxybenzophenone as a cross-linkable monomer, and ethyl acetate as a solvent in a reaction solution containing a polymer block A partial polymer, respectively. It was supplied in the indicated amounts. The reaction solution was kept at 60 ° C. for 6 hours to perform reversible chain transfer polymerization (RAFT) to obtain a polymer block A-polymer block B partial polymer. The peak top molecular weight and weight average molecular weight of the polymer block A-polymer block B partial polymer are shown in Tables 5 and 6.

Polymer block A-polymer block B Partial polymer-containing reaction solution is cross-linkable with isobornyl acrylate, N-acryloyl morpholine, 4-t-butylcyclohexyl acrylate and n-butyl acrylate as non-crosslinkable monomers. 4-Acryloyloxybenzophenone, 4- [2- (acryloyloxy) ethoxy] benzophenone and 4-hydroxybutyl acrylate glycidyl ether as a monomer, and ethyl acetate as a solvent were supplied in the amounts shown in Tables 1 and 2, respectively. The reaction solution was kept at 60 ° C. for 6 hours and reversible chain transfer polymerization (RAFT) was carried out to prepare a crosslinkable block copolymer. Ethyl acetate was added to the reaction solution so that the content of the crosslinkable block copolymer was 50% by mass to obtain a crosslinkable block copolymer solution. The crosslinkable block copolymer was an ABA type triblock copolymer in which the polymer block A was bonded to both ends of the polymer block B. The peak top molecular weight, weight average molecular weight and dispersity of the crosslinkable block copolymer are shown in Tables 5 and 6. The total content of the polymer block A and the content of the polymer block B of the crosslinkable block copolymer are shown in Tables 5 and 6.

(Comparative Example 5)
In a separable flask equipped with a stirrer, a cooling tube, a thermometer and a nitrogen gas inlet, n-butyl acrylate and isobornyl acrylate as non-crosslinkable monomers, 4-acryloyloxybenzophenone as crosslinkable monomers, and trithiocarbonate. 2-[(Dodecylsulfanylthiocarbonyl) sulfanyl] propanoic acid as a compound and ethyl acetate as a solvent were supplied in the amounts shown in Table 3 and stirred to prepare a reaction solution.

After replacing the inside of the separable flask with nitrogen gas, the reaction solution was maintained at 60 ° C. using a water bath. Next, reversible chain transfer polymerization (RAFT) was started by supplying 2,2'-azobis (isobutyronitrile) as a polymerization initiator to the reaction solution in the separable flask in the amounts shown in Table 3. The reaction solution was kept at 60 ° C. for 6 hours and reversible chain transfer polymerization (RAFT) was carried out to obtain a crosslinkable random polymer. Ethyl acetate was added to the reaction solution so that the content of the crosslinkable random polymer was 50% by mass to obtain a crosslinkable random polymer solution. Table 3 shows the peak top molecular weight, weight average molecular weight, and dispersity of the crosslinkable random polymer.

(Comparative Example 6)
In a separable flask equipped with a stirrer, a cooling tube, a thermometer and a nitrogen gas inlet, n-butyl acrylate as a non-bridging monomer and 1,4-bis {[(dodecyl sulfanyl thiocarbonyl) sulfanyl as a trithiocarbonate compound ] Methyl} benzene and ethyl acetate as a solvent were supplied in the amounts shown in Table 4 and stirred to prepare a reaction solution.

After replacing the inside of the separable flask with nitrogen gas, the reaction solution was maintained at 60 ° C. using a water bath. Next, reversible chain transfer polymerization (RAFT) was started by supplying 2,2'-azobis (isobutyronitrile) as a polymerization initiator to the reaction solution in the separable flask in the amounts shown in Table 4. The reaction solution was kept at 60 ° C. for 6 hours to obtain a polymer block B partial polymer. Table 4 shows the peak top molecular weight and the weight average molecular weight of the polymer block B partial polymer.

In the reaction solution containing the polymer block B partial polymer, N-acryloylmorpholin as a non-crosslinkable monomer, 4-acryloyloxybenzophenone as a crosslinkable monomer, and ethyl acetate as a solvent were added in the amounts shown in Table 4, respectively. It was supplied one by one. The reaction solution was kept at 60 ° C. for 6 hours and reversible chain transfer polymerization (RAFT) was carried out to prepare a crosslinkable block copolymer. Ethyl acetate was added to the reaction solution so that the content of the crosslinkable block copolymer was 50% by mass to obtain a crosslinkable block copolymer solution. The crosslinkable block copolymer was an ABA type triblock copolymer in which the polymer block A was bonded to both ends of the polymer block B. Table 4 shows the peak top molecular weight, weight average molecular weight, and dispersity of the crosslinkable block copolymer. Table 4 shows the total content of the polymer block A and the content of the polymer block B of the crosslinkable block copolymer.

(Preparation of coating agent)
The crosslinkable block copolymer solutions of Examples 1, 2 and 4 to 13, and the crosslinkable block copolymer solutions of Comparative Examples 1 to 4 and 6 and the crosslinkable random polymer solution of Comparative Example 5 were used as coating agents without any treatment.

2 parts by mass of a triarylsulfonium salt-based photoacid generator (trade name "CPI-200K" manufactured by San-Apro) as a photoacid generator (UV cation generator) in 100 parts by mass of the crosslinkable block copolymer solution of Example 3. Was added and mixed uniformly to obtain a coating agent.

For the crosslinkable block copolymers obtained in Examples and Comparative Examples and the block copolymers crosslinked with the crosslinkable block copolymers, the decay curves were measured as described above, and based on this decay curve, the decay curves were measured. Spin-spin relaxation times T ₂ (1) and T ₂ (2), and component ratios A ₁ and A ₂ were obtained. The rate of change (%) of relaxation time T ₂ (2) was also calculated. The gel fractions of the block copolymers and random polymers after cross-linking are shown in Tables 3-6.

A graph showing the attenuation curve of the crosslinkable block copolymer obtained in Example 1 and the relaxation curve obtained by fitting the attenuation curve to the two-component relaxation curve is shown in FIG. The vertical axis is the "signal intensity ratio when the maximum intensity of the attenuation curve is 1." The component ratio A ₁ of the transition curve can be read from the value of the Y-axis intercept of the transition curve having the spin-spin relaxation time T ₂ (1). The component ratio A ₂ of the transition curve can be read from the value of the Y-axis intercept of the transition curve having the spin-spin relaxation time T ₂ (2).

The probe tack of the film formed by cross-linking the cross-linkable block copolymer and the cross-linkable random polymer obtained in Examples and Comparative Examples was measured as described above, and the results are shown in Tables 3 to 6. The gel fraction of the film is shown in the column of "Gel fraction at the time of probe tack measurement" in Tables 3 to 6.

For the crosslinkable block copolymers and the crosslinkable random polymers obtained in Examples and Comparative Examples, the breaking stress and breaking elongation before and after crosslinking were measured as follows, and the results are shown in Tables 3 to 6.

(Breaking stress and breaking elongation)
A crosslinkable block copolymer solution or a crosslinkable random polymer solution is coated on the release-treated polyethylene terephthalate film so that the thickness of the crosslinkable block copolymer or the crosslinkable random polymer after removing the solvent is 50 μm. To do. The polyethylene terephthalate film was supplied to an oven and heated at 80 ° C. for 3 minutes to remove ethyl acetate, and two coating films were prepared by laminating the coating film on the polyethylene terephthalate film. A flat rectangular coating test piece having a length of 100 mm and a width of 50 mm was cut out from one coating film.

Using an ultraviolet irradiation device (trade name "Light Hammer 6" (using H valve) manufactured by Heleus (former Fusion UV Systems)), UV-C irradiation intensity: approx. 48 mW / cm ² , UV-C integrated light intensity: 100 mJ / cm ^{In step 2,} ultraviolet rays (UV-C) were applied to the coating film of the remaining one coating film to prepare a film film in which the film was laminated on polyethylene terephthalate. A flat rectangular film test piece having a length of 100 mm and a width of 50 mm was cut out from the film.

The coating test piece and the film test piece were masked at both ends 25 mm in the vertical direction to expose the coating film of the coating test piece and the film of the film test piece in a planar square shape having a side of 50 mm. The polyethylene terephthalate film was peeled off from the coating test piece and the film test piece to prepare a sample for measuring the stress-strain curve. A sample for measuring the stress-strain curve was subjected to a tensile test at a tensile speed of 500 mm / min using an autograph (trade name "AGS-X100N" manufactured by Shimadzu Corporation). The test force (N) and displacement (mm) when the sample for measuring the stress-strain curve was broken were read, and the breaking stress and breaking elongation were calculated based on the following formulas.
Breaking stress (N / mm ² )
= Test force (N) / [Sample thickness (μm) x 50 (mm) for stress-strain curve measurement]
Elongation at break (%) = displacement (mm) x 2

According to the present invention, it is possible to provide a crosslinkable block copolymer capable of forming a tough and tackless film and a coating agent using the crosslinkable block copolymer.

(Cross-reference of related applications)
This application claims priority under Japanese Patent Application No. 2019-5254 filed on January 16, 2019, and the disclosure of this application is incorporated herein by reference in its entirety. ..

C The relaxation curve having the shorter spin-spin relaxation time T ₂ (1) among the relaxation curves obtained by fitting the two-component relaxation curve by fitting the decay curve using the nonlinear minimum square method D The attenuation curve is the nonlinear minimum square method. Of the relaxation curves obtained by fitting the two-component relaxation curve using, the relaxation curve E decay curve having the longer spin-spin relaxation time T ₂ (2).

Claims (7)

Polymer block B and
The polymer block A containing a monomer unit bonded to each of both ends of the polymer block B and having crosslinkability is included.
After cross-linking, the shorter spin-spin relaxation when the attenuation curve obtained by the Solid echo method in ¹ H pulse NMR (20 MHz) at 40 ° C. is fitted to a two-component relaxation curve using the nonlinear least squares method. A crosslinkable block characterized in that the time T ₂ (1) is 18 to 35 μsec and the component ratio A _{1 of the} relaxation curve having the spin-spin relaxation time T ₂ (1) is 40 to 70%. Polymer. The crosslinkable block copolymer according to claim 1, wherein the polymer block A contains a monomer unit having a saturated aliphatic ring structure. Claimed that the monomer unit having a saturated aliphatic ring structure contains at least one monomer unit selected from the group consisting of isobornyl (meth) acrylate units and 4-t-butylcyclohexyl (meth) acrylate units. Item 2. The crosslinkable block copolymer according to Item 2. The second aspect of claim 2, wherein the content of the monomer unit having a saturated aliphatic ring structure in the monomer units constituting the polymer block A is 30.0 to 59.6% by mass. Crosslinkable block copolymer. The crosslinkable block copolymer according to claim 3, wherein the polymer block A further contains N- (meth) acryloylmorpholine units. The crosslinkable block copolymer according to any one of claims 1 to 5, wherein the crosslinkable monomer unit contains a radiation crosslinkable monomer unit. A coating agent containing the crosslinkable block copolymer according to any one of claims 1 to 6.

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