JP2018145276A - (meth) acrylic block copolymer and active energy ray-curable composition containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a (meth) acrylic block copolymer that is low in low viscosity, and excellent in a curing rate and the flexibility of a cured product.SOLUTION: A (meth) acrylic block copolymer contains: a methacrylic polymer block (A) having an active energy ray-curable group containing a partial structure represented by formula (1); and an acrylic polymer block (B) containing no active energy ray-curable group. The methacrylic polymer block (A) contains: a methacrylic acid methyl-derived monomer unit (a1), and an alkyl methacrylate-derived monomer unit (a2) having an alkyl group with 4 or more carbon atoms, containing no active energy ray-curable group (In the formula (1), Ris a hydrogen atom or a C1-20 hydrocarbon group).SELECTED DRAWING: None

Description

  The present invention relates to a (meth) acrylic block copolymer, an active energy ray-curable composition containing the (meth) acrylic block copolymer, and a cured product thereof. Specifically, it is a low-viscosity (meth) acrylic block copolymer excellent in curing speed and cured product, an active energy ray-curable composition containing the (meth) acrylic block copolymer, and these Relates to the cured product.

  Active energy ray-curable compositions that are cured by irradiation with active energy rays such as ultraviolet rays and electron beams are known, and are used for applications such as adhesives, adhesives, paints, inks, coating materials, and optical modeling materials. It has been.

  On the other hand, a (meth) acrylic block copolymer consisting of a methacrylic polymer block and an acrylic polymer block is excellent in tackiness, moldability, weather resistance, etc., making use of these characteristics, adhesives, adhesives, coatings Expansion to applications such as materials and various molding materials is expected.

  Furthermore, as a material having these characteristics, active energy ray curing comprising a methacrylic polymer block and an acrylic polymer block, which is activated by irradiation of active energy rays or by a photoinitiator activated by the irradiation. A (meth) acrylic block copolymer having a functional group is known (see Patent Document 1). Such a (meth) acrylic block copolymer is formed, for example, by polymerizing butyl acrylate to form an acrylic polymer block, and then copolymerizing methyl methacrylate and 2-hydroxyethyl methacrylate to produce a hydroxyl group-containing methacrylic polymer. It is obtained by forming a block and reacting a hydroxyl group of the resulting block copolymer with acryloyl chloride to introduce an acryloyl group that becomes an active energy ray-curable group.

  The subject of an active energy ray-curable composition includes an improvement in the curing rate when irradiated with an active energy ray. Usually, the curing rate is improved by increasing the content of the active energy ray-curable group in the active energy ray-curable composition. However, in the conventional (meth) acrylic block copolymer, acryloyl chloride is used. It was difficult to increase the content of the active energy ray-curable group because of the low reaction rate of

  Moreover, the improvement of the coating property in uses, such as an adhesive agent, an adhesive, a coating material, an ink, a coating material, is mentioned as another subject of an active energy ray curable composition. Usually, in order to improve the coating property of the active energy ray-curable composition, it is necessary to lower the viscosity, and a method of adding a low molecular weight monomer or oligomer or a method of adding a plasticizer is known. Yes.

  However, if the active energy ray-curable material contains a large amount of a low molecular weight monomer or oligomer, adverse effects such as loss of flexibility of the cured product occur. In addition, when a plasticizer is added, when the obtained cured product is used for a long period of time, problems such as peripheral contamination and a decrease in flexibility of the cured product may occur due to migration of the plasticizer.

  Patent Document 1 describes a method for decreasing the viscosity by decreasing the molecular weight of the (meth) acrylic block copolymer and decreasing the content of the methacrylic polymer block in the (meth) acrylic block copolymer. However, no mention is made regarding the compatibility between the curing speed and the flexibility of the cured product.

JP 2011-184678 A

  Accordingly, an object of the present invention is a (meth) acrylic block copolymer having low viscosity, excellent curing speed and flexibility of a cured product, and active energy ray curable containing the (meth) acrylic block copolymer. It is to provide compositions and cured products thereof.

According to the present invention, the above object can be achieved by the following aspects.
[1]: A methacrylic polymer block (A) having an active energy ray-curable group containing a partial structure represented by the following general formula (1), and an acrylic polymer block having no active energy ray-curable group (B) and
The methacrylic polymer block (A) is a methacrylic acid alkyl ester having a monomer unit (a1) derived from methyl methacrylate and an alkyl group having 4 or more carbon atoms that does not have an active energy ray-curable group. A (meth) acrylic block copolymer containing the derived monomer unit (a2).

(In the formula (1), ^{R 1} represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.)
[2]: The (meth) acrylic block copolymer according to [1], wherein the homopolymer has a glass transition temperature (Tg2) of 50 ° C. or less.
[3]: The content of the monomer unit (a2) relative to all monomer units forming the methacrylic polymer block (A) is 0.1 to 30 mol%, [1] or [2 ] The (meth) acrylic block copolymer as described in.
[4] An active energy ray-curable composition containing the (meth) acrylic block copolymer according to any one of [1] to [3] above.
[5]: A cured product of the (meth) acrylic block copolymer according to any one of [1] to [3] above, or a cured product of the active energy ray-curable composition according to [4].

  According to the present invention, a (meth) acrylic block copolymer having a low viscosity, excellent curing speed and flexibility of a cured product, and an active energy ray-curable composition containing the (meth) acrylic block copolymer And cured products thereof.

Hereinafter, the present invention will be described in detail.
In the present specification, “(meth) acryl” means a generic name of “methacryl” and “acryl”, and “(meth) acryloyl” described later means a generic name of “methacryloyl” and “acryloyl”. The “(meth) acrylate” described later means a generic name of “methacrylate” and “acrylate”.

  The (meth) acrylic block copolymer of the present invention contains a methacrylic polymer block (A) and an acrylic polymer block (B).

<Methacrylic polymer block (A)>
The methacrylic polymer block (A) has an active energy ray-curable group containing a partial structure represented by the following general formula (1) (hereinafter sometimes referred to as “partial structure (1)”).

In the general formula (1), R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.

  The active energy ray-curable group containing the partial structure (1) exhibits polymerizability upon irradiation with an active energy ray. Therefore, the (meth) acrylic block copolymer of the present invention or the active energy ray-curable composition containing the same is cured by irradiation with active energy rays to become a cured product. In addition, in this specification, an active energy ray means a light beam, electromagnetic waves, particle beams, and a combination thereof. Examples of light rays include far ultraviolet rays, ultraviolet rays (UV), near ultraviolet rays, visible rays, and infrared rays, electromagnetic waves include X-rays and γ rays, and particle beams include electron beams (EB) and proton rays (α Line) and neutron beam. Among these active energy rays, ultraviolet rays and electron beams are preferable, and ultraviolet rays are more preferable, from the viewpoints of curing speed, availability of an irradiation apparatus, price, and the like.

In the general formula (1), examples of the hydrocarbon group having 1 to 20 carbon atoms represented by R ¹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, sec- Butyl group, t-butyl group, 2-methylbutyl group, 3-methylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, n-pentyl group, neopentyl Group, n-hexyl group, 2-methylpentyl group, 3-methylpentyl group, n-decyl group and other alkyl groups; cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group and other cycloalkyl groups; phenyl group, naphthyl Aryl groups such as a group; and aralkyl groups such as a benzyl group and a phenylethyl group. R ¹ is preferably a hydrogen atom, a methyl group, or an ethyl group from the viewpoint of active energy ray curability, and most preferably a methyl group.

  From the viewpoint of curing speed, the partial structure (1) is preferably present as a part of the partial structure represented by the following general formula (2) (hereinafter sometimes referred to as “partial structure (2)”). .

In the general formula (2), R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, R ² and R ³ each independently represent a hydrocarbon group having 1 to 6 carbon atoms, and X represents O, S, or N (R ⁴ ) (R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms), and n represents an integer of 1 to 20.

In the general formula (2), preferred examples of embodiment and ^{R 1} a hydrocarbon group having 1 to 20 carbon atoms represented ^{by R 1} is the same as ^{R 1} in formula (1).

In the general formula (2), examples of the hydrocarbon group having 1 to 6 carbon atoms independently represented by R ² and R ³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and n-butyl. Group, isobutyl group, sec-butyl group, t-butyl group, 2-methylbutyl group, 3-methylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group Alkyl groups such as n-pentyl group, neopentyl group, n-hexyl group, 2-methylpentyl group and 3-methylpentyl group; cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group; phenyl group Aryl groups and the like. Among these, from the viewpoint of curing speed, a methyl group and an ethyl group are preferable, and a methyl group is most preferable.

In the general formula (2), X represents O, S or N (R ⁴ ) (R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms), and O is easy to control polymerization. Is preferred. Here, O is an oxygen atom, S is a sulfur atom, and N is a nitrogen atom. When X is N (R ⁴ ), the hydrocarbon group having 1 to 6 carbon atoms represented by R ⁴ is, for example, a hydrocarbon having 1 to 6 carbon atoms represented by R ² and R ^{3 in} the general formula (2). The same thing as a group is mentioned. R ⁴ may be the same hydrocarbon group as R ² to R ³ or another hydrocarbon group.

  In the general formula (2), the integer of 1 to 20 represented by n is preferably 2 to 5 from the viewpoint of the viscosity and the curing rate of the (meth) acrylic block copolymer.

  The number of partial structures (1) contained in the (meth) acrylic block copolymer of the present invention is preferably 2 or more, and more preferably 4 or more.

  The content of the partial structure (1) with respect to all monomer units constituting the methacrylic polymer block (A) is preferably in the range of 0.1 mol% to 50 mol%, and 0.3 mol % Is more preferably in the range of not less than 30% and not more than 30% by mole, and still more preferably in the range of not less than 0.5% by mole and less than 10% by mole.

  The content of the partial structure (2) with respect to all the monomer units constituting the methacrylic polymer block (A) is preferably in the range of 0.1 mol% to 50 mol%, and 0.3 mol % Is more preferably in the range of not less than 30 mol% and not more than 30 mol%, and still more preferably in the range of not less than 0.5 mol% and less than 10 mol%.

  The active energy ray-curable group containing the partial structure (1) may be at the terminal or the side chain of the methacrylic polymer block (A), but the partial structure (1) having a preferable content is introduced. From this viewpoint, it is preferably at least in the side chain.

  The methacrylic polymer block (A) may include a monomer unit derived from a polyfunctional methacrylic acid ester having two or more methacryloyl groups. A methacrylic polymer block (A) having an active energy ray-curable group containing a partial structure (1) by leaving a part of the plurality of methacryloyl groups possessed by such a polyfunctional methacrylate after polymerization, and can do.

When a bifunctional methacrylate represented by the following general formula (3) (hereinafter referred to as “dimethacrylate (3)”) is used as the polyfunctional methacrylate, the living anion polymerization is performed under the conditions described later. One methacryloyl group (a methacryloyl group to which “O (CH ₂ ) _n ” in the following general formula (3) is directly linked) is selectively polymerized to form a methacrylic polymer block having the aforementioned partial structure (2) ( Since A) is obtained, it is preferable.

In the general formula (3), R ² and R ³ each independently represent a hydrocarbon group having 1 to 6 carbon atoms, and n represents an integer of 1 to 20.

In the general formula (3), examples of the hydrocarbon group having 1 to 6 carbon atoms represented by R ² and R ³ include the same hydrocarbon groups as R ² and R ^{3 in} the general formula (2). In the general formula (3), the integer of 1 to 20 represented by n is preferably 2 to 5 from the viewpoint of the viscosity and the curing rate of the (meth) acrylic block copolymer.

  Specific examples of the dimethacrylate (3) include, for example, 1,1-dimethylpropane-1,3-diol dimethacrylate, 1,1-dimethylbutane-1,4-diol dimethacrylate, 1,1-dimethylpentane-1 , 5-diol dimethacrylate, 1,1-dimethylhexane-1,6-diol dimethacrylate, 1,1-diethylpropane-1,3-diol dimethacrylate, 1,1-diethylbutane-1,4-diol di Methacrylate, 1,1-diethylpentane-1,5-diol dimethacrylate, 1,1-diethylhexane-1,6-diol dimethacrylate and the like can be mentioned, among which 1,1-dimethylpropane-1,3- Diol dimethacrylate, 1,1-dimethylbutane-1,4-diol dimethacrylate, , 1-dimethyl-1,5-diol dimethacrylate, and 1,1-dimethyl hexane-1,6-diol dimethacrylate are preferred, 1,1-dimethyl-1,3-diol dimethacrylate are more preferred. In addition, these dimethacrylates may be used individually by 1 type, or may use 2 or more types together.

  The content of the monomer unit derived from the polyfunctional methacrylic acid ester with respect to all the monomer units of the methacrylic polymer block (A) is preferably 70 mol% or less, and 60 mol% or less. Is more preferable, and it is further more preferable that it is 50 mol% or less. When dimethacrylate (3) is used as the polyfunctional methacrylic acid ester, the content of monomer units derived from dimethacrylate (3) relative to all monomer units of the methacrylic polymer block (A) is: It is preferably in the range of 0.1 mol% or more and 50 mol% or less, more preferably in the range of 0.3 mol% or more and 30 mol% or less, and 0.5 mol% or more and less than 10 mol%. More preferably, it is within the range.

The methacrylic polymer block (A) contains a monomer unit (a1) derived from methyl methacrylate. The content of the monomer unit (a1) derived from methyl methacrylate with respect to all the monomer units of the methacrylic polymer block (A) is preferably 30% by mass or more, and 40% by mass or more. More preferably, it is more preferably 50% by mass or more.
Further, the content of the monomer unit (a1) derived from methyl methacrylate with respect to all the monomer units of the methacrylic polymer block (A) may be in the range of 20 to 99.8 mol%. Preferably, it is in the range of 50 to 99.8 mol%.

  The methacrylic polymer block (A) contains a monomer unit (a2) derived from a methacrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms and having no active energy ray-curable group. By containing the monomer unit (a2) in the methacrylic polymer block (A), the cohesive force of the methacrylic polymer block (A) in the (meth) acrylic block copolymer is reduced. The viscosity of the (meth) acrylic block copolymer, and thus the active energy ray-curable composition containing it, is lowered.

  Examples of the methacrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms not having an active energy ray-curable group include n-butyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, and 2-ethylhexyl methacrylate. , Isobornyl methacrylate, dodecyl methacrylate and the like. Among these, methacrylic acid alkyl esters having an acyclic alkyl group such as n-butyl methacrylate, 2-ethylhexyl methacrylate and dodecyl methacrylate are preferable, and n-butyl methacrylate and 2-ethylhexyl methacrylate are more preferable. In addition, these alkyl methacrylates may be used individually by 1 type, or may use 2 or more types together.

The methacrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms and having no active energy ray-curable group has a glass transition temperature (Tg2) of a homopolymer obtained by polymerizing it alone of 50 ° C. or less. Some are preferred, and more preferably 30 ° C. or lower. When the glass transition temperature (Tg2) satisfies the above value, the cohesive force of the methacrylic polymer block (A) in the (meth) acrylic block copolymer is reduced, and the (meth) acrylic block copolymer, As a result, the viscosity of the active energy ray-curable composition containing it decreases.
The glass transition temperature may be measured by homopolymerizing the target alkyl methacrylate by a known method and measuring the obtained polymer by the following method.

  In accordance with JIS K7121, using a differential scanning calorimeter (DSC-50 (product number) manufactured by Shimadzu Corporation), the temperature was raised to 230 ° C. for the first time, then cooled to room temperature, and then from room temperature to 230 The DSC curve is measured under the condition that the temperature is raised to 10 ° C./min for the second time at 10 ° C./min. The midpoint glass transition temperature obtained from the DSC curve measured at the second temperature rise is defined as the glass transition temperature in the present specification.

  The content of the monomer unit (a2) with respect to all the monomer units forming the methacrylic polymer block (A) is preferably in the range of 0.1 to 30 mol%, More preferably, it is within the range of 20 mol%. Within this range, the (meth) acrylic block copolymer, and thus the active energy ray-curable composition containing it, can be kept at a high curing rate while lowering the viscosity. The content of the monomer unit (a2) with respect to all monomer units forming the methacrylic polymer block (A) is more than 10% by mass because the effects of the present invention are more remarkably exhibited. Preferably there is.

  The methacrylic polymer block (A) may have a monomer unit (a3) derived from a methacrylic acid ester other than the monomer unit (a1) and the monomer unit (a2).

The methacrylic polymer block (A) may have a monomer unit derived from another monomer other than the methacrylic acid ester. Examples of the other monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, cyclohexyl acrylate, and 2-ethylhexyl acrylate. Alkyl acrylates such as isobornyl acrylate and dodecyl acrylate; 2-methoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxybutyl acrylate, trimethoxysilylpropyl acrylate, 2-aminoethyl acrylate, N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate, phenyl acrylate, naphthyl acrylate, 2- (trimethylsilyloxy) ethyl acrylate, 3- (trimethylsilyloxy) propyl acrylate, Glycidyl crylate, γ- (acryloyloxypropyl) trimethoxysilane, ethylene oxide adduct of acrylic acid, trifluoromethylmethyl acrylate, 2-trifluoromethylethyl acrylate, 2-perfluoroethylethyl acrylate, acrylic acid 2-perfluoroethyl-2-perfluorobutylethyl, 2-perfluoroethyl acrylate, perfluoromethyl acrylate, diperfluoromethyl methyl acrylate, 2-perfluoromethyl-2-perfluoroethyl methyl acrylate, Acrylic acid esters such as 2-perfluorohexylethyl acrylate, 2-perfluorodecylethyl acrylate, 2-perfluorohexadecylethyl acrylate; methyl α-methoxyacrylate, methyl α-ethoxyacrylate An α-alkoxy acrylate ester; a crotonic acid ester such as methyl crotonate and ethyl crotonate; a 3-alkoxy acrylate ester such as 3-methoxy acrylate; N-isopropyl (meth) acrylamide, Nt-butyl ( (Meth) acrylamides such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide; methyl 2-phenylacrylate, ethyl 2-phenylacrylate, 2-bromoacrylic acid n -Butyl, methyl 2-bromomethyl acrylate, ethyl 2-bromomethyl acrylate, methyl vinyl ketone, ethyl vinyl ketone, methyl isopropenyl ketone, ethyl isopropenyl ketone and the like. These other monomers may be used alone or in combination of two or more.
The content of the monomer unit formed by the other monomer is preferably 10% by mass or less, and preferably 5% by mass with respect to the total monomer units of the methacrylic polymer block (A). The following is more preferable. In addition, the content of the monomer unit formed by the other monomer is such that, when the methacrylic polymer block (A) is contained in the (meth) acrylic block copolymer, each polymer In each block, 10 mass% or less is preferable and 5 mass% or less is more preferable.

The number average molecular weight (Mn _A ) of the methacrylic polymer block (A) is not particularly limited, but is 500 to 100 from the viewpoint of handleability, viscosity, mechanical properties, etc. of the obtained (meth) acrylic block copolymer. Is preferably in the range of 1,000, more preferably in the range of 1,000 to 10,000. When a plurality of methacrylic polymer blocks (A) are contained in the (meth) acrylic block copolymer, the number average molecular weight of each polymer block is preferably in the above range.
In the present specification, the number average molecular weight and the molecular weight distribution described later are values measured by a gel permeation chromatography (GPC) method (standard polystyrene conversion).

  The content of the methacrylic polymer block (A) in the (meth) acrylic block copolymer of the present invention is not particularly limited, but is preferably 1 to 30% by mass, and 4 to 25% by mass. Is more preferable, and it is further more preferable that it is 5-20 mass%. When the content is 30% by mass or less, a cured product obtained by curing the (meth) acrylic block copolymer of the present invention tends to be excellent in flexibility, and when the content is 1% by mass or more, the present invention. It tends to be excellent in the curing rate when the active energy ray is irradiated to the (meth) acrylic block copolymer. When a plurality of methacrylic polymer blocks (A) are contained in the (meth) acrylic block copolymer, the total content of all methacrylic polymer blocks (A) satisfies the above value. preferable.

<Acrylic polymer block (B)>
The (meth) acrylic block copolymer of the present invention contains an acrylic polymer block (B) having no active energy ray-curable group.

In the present specification, the active energy ray-curable group means a functional group that exhibits polymerizability upon irradiation with the aforementioned active energy rays. Examples of the active energy ray-curable group include ethylenic double bonds such as the aforementioned partial structure (1), (meth) acryloyl group, vinyl group, allyl group, vinyloxy group, 1,3-dienyl group, and styryl group. (In particular, an ethylenic double bond represented by the general formula CH ₂ ═CR— (wherein R is an alkyl group or a hydrogen atom)), including an epoxy group, an oxetanyl group, a thiol group, a maleimide group, and the like Is mentioned.

  Examples of the acrylic ester that can form the acrylic polymer block (B) include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, and t-butyl acrylate. N-hexyl acrylate, n-heptyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, isobornyl acrylate, dodecyl acrylate, cyclohexyl acrylate, 2-methoxyethyl acrylate, acrylic acid 2-methoxypropyl, 3-methoxypropyl acrylate, 2-methoxybutyl acrylate, 4-methoxybutyl acrylate, 2-ethoxyethyl acrylate, 3-ethoxypropyl acrylate, 4-ethoxybutyl acrylate, methoxydi Tylene glycol acrylate, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, ethoxytriethylene glycol acrylate, methoxydipropylene glycol acrylate, ethoxydipropylene glycol acrylate, methoxytripropylene glycol acrylate, ethoxytripropylene glycol acrylate, trimethoxysilylpropyl acrylate Mono, such as N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate, phenyl acrylate, naphthyl acrylate, 2- (trimethylsilyloxy) ethyl acrylate, 3- (trimethylsilyloxy) propyl acrylate An acrylic ester is mentioned. Among them, alkyl acrylate esters having an alkyl group having 4 or more carbon atoms such as n-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, n-octyl acrylate, etc. Methoxyethyl is preferable, and 2-ethylhexyl acrylate, n-butyl acrylate, and 2-methoxyethyl acrylate are more preferable. These acrylic acid esters may be used alone or in combination of two or more. The content of the monomer unit formed by the acrylate ester is preferably 90% by mass or more, and 95% by mass or more with respect to the total monomer units of the acrylic polymer block (B). More preferably.

  The acrylic polymer block (B) may have a monomer unit derived from another monomer other than the acrylate ester. Examples of the other monomers include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid. Methacrylic acid alkyl esters such as isobornyl acid and dodecyl methacrylate; 2-methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxybutyl methacrylate, trimethoxysilylpropyl methacrylate, 2-aminoethyl methacrylate, methacrylic acid N, N-dimethylaminoethyl, N, N-diethylaminoethyl methacrylate, phenyl methacrylate, naphthyl methacrylate, 2- (trimethylsilyloxy) ethyl methacrylate, 3-methacrylic acid 3- Trimethylsilyloxy) propyl, glycidyl methacrylate, γ- (methacryloyloxypropyl) trimethoxysilane, ethylene oxide adduct of methacrylic acid, trifluoromethylmethyl methacrylate, 2-trifluoromethylethyl methacrylate, 2-perfluoromethacrylate Ethyl ethyl, 2-perfluoroethyl-2-perfluorobutyl ethyl methacrylate, 2-perfluoroethyl methacrylate, perfluoromethyl methacrylate, diperfluoromethyl methyl methacrylate, 2-perfluoromethyl-2-methacrylate Methacrylates such as perfluoroethylmethyl, 2-perfluorohexylethyl methacrylate, 2-perfluorodecylethyl methacrylate, 2-perfluorohexadecylethyl methacrylate, etc. Steal; α-alkoxyacrylic acid esters such as methyl α-methoxyacrylate and methyl α-ethoxyacrylate; Crotonic acid esters such as methyl crotonate and ethyl crotonate; 3-alkoxyacrylic acids such as 3-methoxyacrylic acid ester Esters; (Meth) acrylamides such as N-isopropyl (meth) acrylamide, Nt-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide; methyl vinyl ketone, Examples thereof include ethyl vinyl ketone, methyl isopropenyl ketone, and ethyl isopropenyl ketone. These other monomers may be used alone or in combination of two or more. The content of the monomer unit formed by the other monomer is preferably 10% by mass or less, and preferably 5% by mass with respect to the total monomer units of the acrylic polymer block (B). The following is more preferable.

The number average molecular weight (Mn _B ) of the acrylic polymer block (B) is not particularly limited, but is 3,000 from the viewpoint of handleability, viscosity, mechanical properties and the like of the obtained (meth) acrylic block copolymer. It is preferably in the range of ˜300,000, more preferably in the range of 5,000 to 200,000. When a plurality of acrylic polymer blocks (B) are contained in the (meth) acrylic block copolymer, the number average molecular weight of each polymer block is preferably in the above range.

  The content of the acrylic polymer block (B) in the (meth) acrylic block copolymer of the present invention is not particularly limited, but is preferably 70 to 99% by mass, and 75 to 96% by mass. Is more preferable, and it is further more preferable that it is 80-95 mass%. When the content is 70% by mass or more, a cured product obtained by curing the (meth) acrylic block copolymer of the present invention tends to be excellent in flexibility, and when it is 99% by mass or less, the present invention. It tends to be excellent in the curing rate when the active energy ray is irradiated to the (meth) acrylic block copolymer. When a plurality of acrylic polymer blocks (B) are contained in the (meth) acrylic block copolymer, the total content of all acrylic polymer blocks (B) satisfies the above value. preferable.

<(Meth) acrylic block copolymer>
The number average molecular weight (Mn) of the (meth) acrylic block copolymer of the present invention is not particularly limited, but is preferably 4,000 to 400,000 from the viewpoints of handleability, viscosity, mechanical properties, and the like. 7,000 to 200,000 is more preferable. The molecular weight distribution of the (meth) acrylic block copolymer of the present invention, that is, the weight average molecular weight / number average molecular weight (Mw / Mn) is preferably 2.00 or less, and is within the range of 1.02 to 2.00. Is more preferable, it is more preferable to be in the range of 1.05 to 1.80, and it is most preferable to be in the range of 1.10 to 1.50.

  The viscosity of the (meth) acrylic block copolymer of the present invention is not particularly limited, but is preferably in the range of 0.1 to 1,000 Pa · s from the viewpoint of handleability such as coating properties, More preferably, it is in the range of 0.1 to 100 Pa · s, and still more preferably in the range of 0.1 to 20 Pa · s. The viscosity can be measured by the method described in the [Viscosity] section of the Examples.

The storage elastic modulus of the cured product of the (meth) acrylic block copolymer of the present invention is not particularly limited, but is preferably 1.0 × 10 ⁵ Pa or less from the viewpoint of handleability, mechanical properties, It is more preferably 1.0 × 10 ⁴ Pa or less, and further preferably 3.5 × 10 ³ Pa or less. It can be said that the lower the value of the storage elastic modulus, the better the flexibility. The storage elastic modulus was measured by preparing an active energy ray-curable composition containing the (meth) acrylic block copolymer to be measured by the method of [Step (6)] described in the Examples. The method described in the section of [Storage modulus] can be used.

  The (meth) acrylic block copolymer of the present invention is a block copolymer containing at least one methacrylic polymer block (A) and at least one acrylic polymer block (B). The (meth) acrylic block copolymer may have a polymer block other than the methacrylic polymer block (A) and the acrylic polymer block (B). The number of each polymer block and the order of bonding are not particularly limited, but the methacrylic polymer block (A) forms at least one terminal of the (meth) acrylic block copolymer from the viewpoint of active energy ray curability. From the viewpoint of ease of production of the (meth) acrylic block copolymer, a linear polymer is more preferable. In particular, a diblock copolymer in which one methacrylic polymer block (A) and one acrylic polymer block (B) are bonded, or methacrylic groups on both ends of one acrylic polymer block (B). A triblock copolymer in which one polymer block (A) is bonded to each other is more preferable.

  When the (meth) acrylic block copolymer of the present invention has a plurality of methacrylic polymer blocks (A), the monomer when the total of the plurality of polymer blocks (A) is used as a whole The content of the unit (a2) is preferably in the range of 0.1 to 30 mol%, and more preferably in the range of 0.1 to 20 mol%.

  The method for producing the (meth) acrylic block copolymer of the present invention is not particularly limited, but it is preferably produced by an anionic polymerization method or a radical polymerization method, and from the viewpoint of polymerization control, by a living anion polymerization method or a living radical polymerization method. More preferably, it is more preferably produced by a living anionic polymerization method.

  Living radical polymerization methods include a polymerization method using a chain transfer agent such as polysulfide, a polymerization method using a cobalt porphyrin complex, a polymerization method using a nitroxide (see International Publication No. 2004/014926), and a high-cycle heterogeneity such as an organic tellurium compound. Polymerization method using elemental compounds (see Japanese Patent No. 3839829), reversible addition / elimination chain transfer polymerization method (RAFT) (see Japanese Patent No. 3639859), atom transfer radical polymerization method (ATRP) (Japanese Patent No. 3040172) , International Publication No. 2004/013192). Among these living radical polymerization methods, an atom transfer radical polymerization method is preferable, and a metal complex having an organic halide or a sulfonyl halide compound as an initiator and at least one selected from Fe, Ru, Ni, and Cu as a central metal. An atom transfer radical polymerization method using as a catalyst is more preferred.

  Living anionic polymerization methods include a method of living polymerization using an organic rare earth metal complex as a polymerization initiator (see JP 06-93060 A), an alkali metal or alkaline earth metal salt using an organic alkali metal compound as a polymerization initiator, etc. A living anion polymerization in the presence of a mineral acid salt (see JP 05-507737 A), and a living anion polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound (Japanese Patent Laid-Open No. Hei 5). 11-335432 and International Publication No. 2013/141105). Among these living anionic polymerization methods, the living anion is prepared by using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound because it can directly and efficiently polymerize the (meth) acrylic block copolymer of the present invention. A method of polymerization is preferred, and a method of living anion polymerization using an organolithium compound as a polymerization initiator in the presence of an organoaluminum compound and a Lewis base is more preferred.

  Examples of the organolithium compound include t-butyllithium, 1,1-dimethylpropyllithium, 1,1-diphenylhexyllithium, 1,1-diphenyl-3-methylpentyllithium, ethyl α-lithioisobutyrate, butyl α-lithioisobutyrate, methyl α-lithioisobutyrate, isopropyl lithium, sec-butyl lithium, 1-methylbutyl lithium, 2-ethylpropyl lithium, 1-methylpentyl lithium, cyclohexyl lithium, diphenylmethyl lithium, α- Examples include methyl benzyl lithium, methyl lithium, n-propyl lithium, n-butyl lithium, n-pentyl lithium and the like. Among them, from the viewpoint of availability and anion polymerization initiating ability, secondary grades such as isopropyl lithium, sec-butyl lithium, 1-methylbutyl lithium, 1-methylpentyl lithium, cyclohexyl lithium, diphenylmethyl lithium, α-methylbenzyl lithium, etc. C3-C40 organolithium compounds having a chemical structure with a carbon atom as an anion center are preferred, and sec-butyllithium is particularly preferred. These organolithium compounds may be used alone or in combination of two or more.

  The amount of the organolithium compound used can be determined by the ratio to the amount of the monomer used depending on the number average molecular weight of the target block copolymer.

As said organoaluminum compound, the organoaluminum compound shown by the following general formula (A-1) or (A-2) is mentioned.
AlR ⁵ (R ⁶ ) (R ⁷ ) (A-1)
In the general formula (A-1), R ⁵ represents a monovalent saturated hydrocarbon group, a monovalent aromatic hydrocarbon group, an alkoxy group, an aryloxy group or an N, N-disubstituted amino group, and R ⁶ And R ⁷ each independently represents an aryloxy group, or R ⁶ and R ⁷ are bonded to each other to form an aryleneoxy group.
AlR ⁸ (R ⁹ ) (R ¹⁰ ) (A-2)
In the general formula (A-2), R ⁸ represents an aryloxy group, and R ⁹ and R ¹⁰ are each independently a monovalent saturated hydrocarbon group, a monovalent aromatic hydrocarbon group, an alkoxy group, or N , Represents an N-disubstituted amino group.

In the above general formulas (A-1) and (A-2), examples of the aryloxy group that R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent include a phenoxy group, a 2-methylphenoxy group, 4 -Methylphenoxy group, 2,6-dimethylphenoxy group, 2,4-di-t-butylphenoxy group, 2,6-di-t-butylphenoxy group, 2,6-di-t-butyl-4-methyl Phenoxy group, 2,6-di-t-butyl-4-ethylphenoxy group, 2,6-diphenylphenoxy group, 1-naphthoxy group, 2-naphthoxy group, 9-phenanthryloxy group, 1-pyrenyloxy group, Examples include 7-methoxy-2-naphthoxy group.

In the general formula (A-1), examples of the aryleneoxy group formed by bonding R ⁶ and R ⁷ to each other include 2,2′-biphenol, 2,2′-methylenebisphenol, 2,2 ′. -Methylenebis (4-methyl-6-tert-butylphenol), (R)-(+)-1,1'-bi-2-naphthol, (S)-(-)-1,1'-bi-2- The functional group etc. which remove | excluded the hydrogen atom of these two phenolic hydroxyl groups in the compound which has two phenolic hydroxyl groups, such as a naphthol, are mentioned.

  In addition, one or more hydrogen atoms contained in the above aryloxy group and aryleneoxy group may be substituted with a substituent. Examples of the substituent include a methoxy group, an ethoxy group, an isopropoxy group, Examples thereof include alkoxy groups such as t-butoxy group; halogen atoms such as chlorine atom and bromine atom.

In the general formulas (A-1) and (A-2), examples of the monovalent saturated hydrocarbon group independently represented by R ⁵ , R ⁹ and R ¹⁰ include a methyl group, an ethyl group, and n-propyl. Group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, 2-methylbutyl group, 3-methylbutyl group, n-octyl group, 2-ethylhexyl group and other alkyl groups; cyclohexyl group, etc. The monovalent aromatic hydrocarbon group includes, for example, an aryl group such as a phenyl group; the aralkyl group such as a benzyl group; and the alkoxy group includes, for example, a methoxy group and an ethoxy group. , Isopropoxy group, t-butoxy group and the like. Examples of the N, N-disubstituted amino group include a dimethylamino group, a diethylamino group, and a diisopropyl group. A dialkylamino group such as a pyramino group; and a bis (trimethylsilyl) amino group. One or more hydrogen atoms contained in the above-mentioned monovalent saturated hydrocarbon group, monovalent aromatic hydrocarbon group, alkoxy group and N, N-disubstituted amino group may be substituted with a substituent. Examples of the substituent include alkoxy groups such as methoxy group, ethoxy group, isopropoxy group and t-butoxy group; halogen atoms such as chlorine atom and bromine atom.

  Examples of the organoaluminum compound represented by the general formula (A-1) include ethylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum and ethylbis (2,6-di-t-butylphenoxy). Aluminum, ethyl [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, isobutylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, isobutylbis (2, 6-di-t-butylphenoxy) aluminum, isobutyl [2,2′-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum, n-octylbis (2,6-di-t-butyl-4- Methylphenoxy) aluminum, n-octylbis (2,6-di-t-butylphenoxy) aluminum, n-o Tyr [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, methoxybis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, methoxybis (2,6-di-) t-butylphenoxy) aluminum, methoxy [2,2′-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum, ethoxybis (2,6-di-t-butyl-4-methylphenoxy) aluminum, ethoxybis (2,6-di-t-butylphenoxy) aluminum, ethoxy [2,2′-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum, isopropoxybis (2,6-di-t-butyl) -4-methylphenoxy) aluminum, isopropoxybis (2,6-di-t-butylphenoxy) Aluminum, isopropoxy [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, t-butoxybis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, t-butoxybis (2,6-di-t-butylphenoxy) aluminum, t-butoxy [2,2′-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum, tris (2,6-di-t-butyl) -4-methylphenoxy) aluminum, tris (2,6-diphenylphenoxy) aluminum and the like. Among them, from the viewpoints of polymerization initiation efficiency, living property of polymerization terminal anion, availability and handling, etc., isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum, isobutylbis (2,6 -Di-t-butylphenoxy) aluminum, isobutyl [2,2'-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum and the like are preferable.

Examples of the organoaluminum compound represented by the general formula (A-2) include diethyl (2,6-di-t-butyl-4-methylphenoxy) aluminum and diethyl (2,6-di-t-butylphenoxy). Aluminum, diisobutyl (2,6-di-t-butyl-4-methylphenoxy) aluminum, diisobutyl (2,6-di-t-butylphenoxy) aluminum, di-n-octyl (2,6-di-t-butyl) -4-methylphenoxy) aluminum, di-n-octyl (2,6-di-t-butylphenoxy) aluminum and the like.
These organoaluminum compounds may be used alone or in combination of two or more.

  The amount of the organoaluminum compound used can be appropriately selected in accordance with the type of solvent, other various polymerization conditions, and the like. It is preferably used within a range of 0.0 mol, more preferably within a range of 1.1 to 5.0 mol, and even more preferably within a range of 1.2 to 4.0 mol. If the amount of the organoaluminum compound used exceeds 10.0 mol with respect to 1 mol of the organolithium compound, it tends to be disadvantageous in terms of economy, and if it is less than 1.0 mol, the polymerization initiation efficiency tends to decrease.

  Examples of the Lewis base include compounds having an ether bond and / or a tertiary amine structure in the molecule.

  Examples of the compound having an ether bond in the molecule used as the Lewis base include ether. The ether is a cyclic ether having two or more ether bonds in the molecule or an acyclic ether having one or more ether bonds in the molecule from the viewpoint of high polymerization initiation efficiency and living property of the polymerization terminal anion. Is preferred. Examples of the cyclic ether having two or more ether bonds in the molecule include crown ethers such as 12-crown-4, 15-crown-5, and 18-crown-6. Examples of the acyclic ether having one or more ether bonds in the molecule include acyclic monoethers such as dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, and anisole; 1,2-dimethoxyethane, 1,2-diethoxy Ethane, 1,2-diisopropoxyethane, 1,2-dibutoxyethane, 1,2-diphenoxyethane, 1,2-dimethoxypropane, 1,2-diethoxypropane, 1,2-diisopropoxypropane 1,2-dibutoxypropane, 1,2-diphenoxypropane, 1,3-dimethoxypropane, 1,3-diethoxypropane, 1,3-diisopropoxypropane, 1,3-dibutoxypropane, , 3-diphenoxypropane, 1,4-dimethoxybutane, 1,4-diethoxybutane, , 4-diisopropoxybutane, 1,4-dibutoxybutane, 1,4-diphenoxybutane and the like acyclic diethers; diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dibutylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol diethyl Ether, dibutylene glycol diethyl ether, triethylene glycol dimethyl ether, tripropylene glycol dimethyl ether, tributylene glycol dimethyl ether, triethylene glycol diethyl ether, tripropylene glycol diethyl ether, tributylene glycol diethyl ether, tetraethylene glycol dimethyl ether, tetrapropylene glycol dimethyl ether Tetrabutylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetrapropylene glycol diethyl ether, acyclic polyethers such as tetramethylammonium butylene glycol diethyl ether. Among these, from the viewpoints of suppressing side reactions and availability, acyclic ether having 1 to 2 ether bonds in the molecule is preferable, and diethyl ether or 1,2-dimethoxyethane is more preferable.

  The compound having a tertiary amine structure in the molecule used as the Lewis base includes tertiary polyamine. A tertiary polyamine means a compound having two or more tertiary amine structures in the molecule. Examples of the tertiary polyamine include N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetraethylethylenediamine, N, N, N ′, N ″, N ″ -pentamethyl. Linear polyamines such as diethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetraamine, tris [2- (dimethylamino) ethyl] amine; 1,3,5-trimethylhexahydro-1, 3,5-triazine, 1,4,7-trimethyl-1,4,7-triazacyclononane, 1,4,7,10,13,16-hexamethyl-1,4,7,10,13,16 -Non-aromatic heterocyclic compounds such as hexaazacyclooctadecane; aromatic heterocyclic compounds such as 2,2'-bipyridyl and 2,2 ': 6', 2 "-terpyridine That.

  In addition, a compound having one or more ether bonds and one or more tertiary amine structures in the molecule may be used as the Lewis base. Examples of such a compound include tris [2- (2-methoxyethoxy) ethyl] amine.

  These Lewis bases may be used alone or in combination of two or more.

  The amount of the Lewis base used is preferably in the range of 0.3 to 5.0 mol with respect to 1 mol of the organic lithium compound from the viewpoints of polymerization initiation efficiency, stability of the polymerization terminal anion, etc. More preferably, it is in the range of -3.0 mol, and further preferably in the range of 1.0-2.0 mol. When the amount of the Lewis base used exceeds 5.0 mol with respect to 1 mol of the organolithium compound, it tends to be disadvantageous in terms of economy, and when it is less than 0.3 mol, the polymerization initiation efficiency tends to decrease.

  Further, the amount of Lewis base used is preferably in the range of 0.2 to 1.2 mol, and preferably in the range of 0.3 to 1.0 mol, with respect to 1 mol of the organoaluminum compound. More preferred.

  The living anionic polymerization is preferably performed in the presence of an organic solvent from the viewpoint of temperature control and uniformizing the inside of the system to facilitate the polymerization. Organic solvents include hydrocarbons such as toluene, xylene, cyclohexane, and methylcyclohexane from the viewpoints of safety, separation from water in washing of the reaction solution after polymerization, ease of recovery / reuse, etc .; chloroform, chloride Halogenated hydrocarbons such as methylene and carbon tetrachloride; esters such as dimethyl phthalate are preferred. These organic solvents may be used alone or in combination of two or more. In addition, it is preferable to deaerate the organic solvent in advance in the presence of an inert gas while performing a drying treatment from the viewpoint of allowing the polymerization to proceed smoothly.

  In the living anion polymerization, if necessary, other additives may be present in the reaction system. Examples of the other additives include inorganic salts such as lithium chloride; metal alkoxides such as lithium methoxyethoxy ethoxide and potassium t-butoxide; tetraethylammonium chloride and tetraethylphosphonium bromide.

  The living anionic polymerization is preferably performed at -30 to 25 ° C. When it is lower than −30 ° C., the polymerization rate is lowered and the productivity tends to be lowered. On the other hand, when the temperature is higher than 25 ° C., it tends to be difficult to carry out with good living property when the monomer containing the dimethacrylate (3) is polymerized.

  The living anionic polymerization is preferably performed in an atmosphere of an inert gas such as nitrogen, argon or helium. Furthermore, it is preferable to carry out under sufficient stirring conditions so that the reaction system becomes uniform.

  In the above living anionic polymerization, as a method of adding an organolithium compound, organoaluminum compound, Lewis base and monomer to the reaction system, the Lewis base is brought into contact with the organoaluminum compound before contacting with the organolithium compound. It is preferable to add. The organoaluminum compound may be added to the reaction system before the monomer or simultaneously. When the organoaluminum compound is added to the reaction system simultaneously with the monomer, the organoaluminum compound may be added after separately mixing with the monomer.

  The living anionic polymerization can be stopped by adding a polymerization terminator such as methanol; acetic acid or hydrochloric acid in methanol; a protic compound such as aqueous solution of acetic acid or hydrochloric acid to the reaction solution. Usually, the amount of the polymerization terminator used is preferably in the range of 1 to 1,000 mol with respect to 1 mol of the organic lithium compound used.

  As a method for separating and obtaining the block copolymer from the reaction solution after the living anionic polymerization is stopped, a known method can be adopted. Examples thereof include a method of pouring the reaction solution into a poor solvent of the block copolymer and precipitating, a method of distilling off the organic solvent from the reaction solution and obtaining a block copolymer.

  In addition, when the metal component derived from the organolithium compound and the organoaluminum compound remains in the block copolymer obtained separately, the physical properties of the block copolymer may be deteriorated, the transparency may be deteriorated, and the like. Therefore, it is preferable to remove the metal component derived from the organolithium compound and the organoaluminum compound after the anionic polymerization is stopped. As a method for removing the metal component, cleaning treatment using an acidic aqueous solution, adsorption treatment using an adsorbent such as ion exchange resin, celite, activated carbon, and the like are effective. Here, as acidic aqueous solution, hydrochloric acid, sulfuric acid aqueous solution, nitric acid aqueous solution, acetic acid aqueous solution, propionic acid aqueous solution, citric acid aqueous solution etc. can be used, for example.

  In the production of the (meth) acrylic block copolymer of the present invention, as a method for introducing the partial structure (1), a monomer containing the dimethacrylate (3) is polymerized to obtain a methacrylic polymer. In addition to the method of forming the block (A), after forming a polymer block containing a partial structure (hereinafter referred to as “precursor structure”) that becomes a precursor of the partial structure (1), A method of converting to the partial structure (1) is also included. A polymer block containing a precursor structure is obtained by polymerizing a monomer containing a polymerizable functional group and a compound containing a precursor structure (hereinafter referred to as “polymerizable precursor”). Examples of the polymerizable functional group include a styryl group, a 1,3-dienyl group, a vinyloxy group, a (meth) acryloyl group, and the like, and a (meth) acryloyl group is preferable. The precursor structure includes a hydroxyl group protected by a hydroxyl group and a protecting group (silyloxy group, acyloxy group, alkoxy group, etc.), an amino group, an amino group protected by a protecting group, a thiol group, and a thiol group protected by a protecting group. As well as isocyanate groups.

  A polymer block containing a hydroxyl group as a precursor structure is reacted with a compound having a partial structure (1) and a partial structure (carboxylic acid, ester, carbonyl halide, etc.) capable of reacting with a hydroxyl group, thereby allowing a methacrylic polymer block (A ) Can be formed. A polymer block containing a hydroxyl group protected by a protecting group as a precursor structure can form a methacrylic polymer block (A) in the same manner after removing the protecting group to form a hydroxyl group.

  The polymer block containing an amino group as a precursor structure has a partial structure (1) and a partial structure capable of reacting with the amino group (carboxylic acid, carboxylic anhydride, ester, carbonyl halide, aldehyde group, isocyanate group, etc.). A methacrylic polymer block (A) can be formed by reacting with a compound. A polymer block containing an amino group protected by a protective group as a precursor structure can form a methacrylic polymer block (A) in the same manner after removing the protective group to form an amino group.

  The polymer block containing a thiol group as a precursor structure comprises a partial structure (1) and a partial structure capable of reacting with a thiol group (carboxylic acid, carboxylic anhydride, ester, carbonyl halide, isocyanate group, carbon-carbon double bond Etc.) can be reacted with a compound having a methacrylic polymer block (A). A polymer block containing a thiol group protected by a protecting group as a precursor structure can form a methacrylic polymer block (A) in the same manner after removing the protecting group to form a thiol group.

  A polymer block containing an isocyanate group as a precursor structure can form a methacrylic polymer block (A) by reacting with a compound having a partial structure (1) and a partial structure (such as a hydroxyl group) capable of reacting with an isocyanate group. .

  In the production of the (meth) acrylic block copolymer of the present invention, as a method for forming the methacrylic polymer block (A), dimethacrylate (3) is used from the viewpoint that the partial structure (2) can be easily introduced directly. A method of polymerizing a monomer containing benzene, typically a method of living anionic polymerization is preferred.

<Active energy ray-curable composition>
The (meth) acrylic block copolymer of the present invention may be cured by curing it, but can be preferably used as a material for an active energy ray-curable composition. In such an active energy ray-curable composition containing the (meth) acrylic block copolymer of the present invention, the content of the (meth) acrylic block copolymer is 10% by mass or more. Is preferable, and it is more preferable that it is 20 mass% or more.

The active energy ray-curable composition may contain a photopolymerization initiator. Examples of the photopolymerization initiator include acetophenones (for example, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropane). -1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, etc.), benzophenones (for example, benzophenone, benzoylbenzoic acid, hydroxybenzophenone, 3,3′-dimethyl) Carbonyl compounds such as -4-methoxybenzophenone, acrylated benzophenone), Michler ketones (for example, Michler ketone), and benzoins (for example, benzoin, benzoin methyl ether, benzoin isopropyl ether, etc.); tetramethylthiuram monosulfide Sulfur compounds such as thioxanthones (eg, thioxanthone, 2-chlorothioxanthone, etc.); acylphosphine oxides (eg, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,4,6-) Phosphorus compounds such as trimethylbenzoyl) -phenylphosphine oxide, etc .; titanocenes (for example, bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole)) -1-yl) -phenyl) titanium and the like; azo compounds (for example, azobisisobutylnitrile and the like), and the like. Moreover, a photoinitiator may be used individually by 1 type, or may use 2 or more types together. Among these, acetophenones and benzophenones are preferable.

  When it contains a photopolymerization initiator, the content thereof is preferably 0.01 to 10 parts by mass, and 0.05 to 8 parts by mass with respect to 100 parts by mass of the (meth) acrylic block copolymer of the present invention. Is more preferable. When it is 0.01 part by mass or more, the curability of the active energy ray-curable composition becomes better, and when it is 10 parts by mass or less, the resulting cured product tends to have good heat resistance.

  Moreover, the said active energy ray curable composition may contain the sensitizer as needed. Examples of the sensitizer include n-butylamine, di-n-butylamine, tri-n-butylphosphine, allylthiouric acid, triethylamine, diethylaminoethyl methacrylate and the like. Among these, diethylaminoethyl methacrylate and triethylamine are preferable.

  When a photopolymerization initiator and a sensitizer are mixed and used, the mass ratio of the photopolymerization initiator and the sensitizer is preferably within the range of 10:90 to 90:10, and 20: More preferably, it is in the range of 80-80: 20.

  In addition to the (meth) acrylic block copolymer of the present invention, the above active energy ray-curable composition has a reactive dilution that exhibits polymerizability by irradiation with active energy rays, as long as the effects of the present invention are not impaired. An agent may be included. The reactive diluent is not particularly limited as long as it is a compound that exhibits polymerizability upon irradiation with active energy rays. For example, styrene, indene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p- Styrene derivatives such as t-butoxystyrene, p-chloromethylstyrene, p-acetoxystyrene and divinylbenzene; fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl benzoate and vinyl cinnamate Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, n-octyl (meth) acrylate, ( Meth) acrylic acid amyl, (meth) acrylic acid isobutyl, (meth) acrylic acid -Butyl, pentyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, (meth) 2-ethylhexyl acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, (meth) ) Isostearyl acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, bornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (meth) Dicyclopentenyloxyethyl acrylate, 4- (meth) acrylic acid Butylcyclohexyl, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, tetrahydroful (meth) acrylate Furyl, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, polyethylene glycol monoester (meth) acrylate, polypropylene glycol monoester (meth) acrylate, (meth) acryl Methoxyethylene glycol acid, ethoxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, dimethylamino (meth) acrylate Ethyl, diethylaminoethyl (meth) acrylate, 7-amino-3,7-dimethyloctyl (meth) acrylate, 4- (meth) acryloylmorpholine, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethoxytri (meth) ) Acrylate, pentaerythritol tri (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tricyclodecanediyldimethanol di (meth) acrylate, polyethylene Glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate , Tripropylene glycol di (meth) acrylate, bisphenol A diglycidyl ether both end (meth) acrylic acid adduct, pentaerythritol tetra (meth) acrylate, 2,4,6-trioxohexahydro-1,3 5-triazine-1,3,5-trisethanol tri (meth) acrylate, N, N′-bis [2-((meth) acryloyloxy) ethyl] -N ″-(2-hydroxyethyl) -1,3 , 5-triazine-2,4,6 (1H, 3H, 5H) -trione, tricyclodecane dimethanol di (meth) acrylate, di (meth) of diol which is an adduct of bisphenol A ethylene oxide or propylene oxide Acrylate, hydrogenated bisphenol A ethylene oxide or propylene oxide Di (meth) acrylate of diol, which is an adduct of id, epoxy (meth) acrylate obtained by adding (meth) acrylate to diglycidyl ether of bisphenol A, and (meth) acryl such as cyclohexanedimethanol di (meth) acrylate Acid derivatives; epoxy acrylate resins such as bisphenol A type epoxy acrylate resins, phenol novolac type epoxy acrylate resins, cresol novolac type epoxy acrylate resins; carboxyl group-modified epoxy acrylate resins; polyols (polytetramethylene glycol, ethylene glycol and adipic acid Polyester diol, ε-caprolactone modified polyester diol, polypropylene glycol, polyethylene glycol, polycarbonate Hydroxyl group-containing urethane resin obtained from hydroxyl-terminated hydrogenated polyisoprene, hydroxyl-terminated polybutadiene, hydroxyl-terminated polyisobutylene, etc.) and organic isocyanate (tolylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, etc.) Urethane acrylate resins obtained by reacting with (meth) acrylates (hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, pentaerythritol triacrylate, etc.); (Meth) acrylic group-introduced resin; polyester acrylate resin; epoxidized soybean oil, epoxy stearate Examples include epoxy compounds such as jill. These reactive diluents may be used alone or in combination of two or more.

  When the active energy ray-curable composition contains a reactive diluent, the content thereof is preferably 5 to 900 parts by mass with respect to 100 parts by mass of the (meth) acrylic block copolymer of the present invention, and 20 -400 mass parts is more preferable. When it is 5 parts by mass or more, the active energy ray-curable composition has a lower viscosity, and when it is 900 parts by mass or less, the active energy ray-curable composition tends to be superior in terms of curing speed and flexibility of the cured product. is there.

  The active energy ray-curable composition has an active energy ray-curable group such as a plasticizer, a tackifier, a softener, a filler, a stabilizer, a pigment, and a dye within a range that does not significantly inhibit the curability. Various additives that do not have may be included.

  The purpose of including the plasticizer in the active energy ray-curable composition is, for example, adjustment of the viscosity of the active energy ray-curable composition, mechanical strength of a cured product obtained by curing the active energy ray-curable composition. Adjustment. Examples of the plasticizer include phthalic acid esters such as dibutyl phthalate, diheptyl phthalate, di (2-ethylhexyl) phthalate, and butyl benzyl phthalate; non-aromatics such as dioctyl adipate, dioctyl sebacate, dibutyl sebacate, and isodecyl succinate. Dibasic acid esters; Aliphatic esters such as butyl oleate and methyl acetylricinoleate; Esters of polyalkylene glycols such as diethylene glycol dibenzoate, triethylene glycol dibenzoate, and pentaerythritol esters; Tricresyl phosphate, tributyl phosphate, and the like Trimellitic acid ester; Polybutadiene, butadiene-acrylonitrile copolymer, diene (co) polymer such as polychloroprene; Polyisobutylenes; chlorinated paraffins; hydrocarbon oils such as alkyldiphenyls and partially hydrogenated terphenyls; process oils; polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the hydroxyl groups of these polyether polyols Polyethers such as derivatives converted to ester groups, ether groups, etc .; dibasic acids such as sebacic acid, adipic acid, azelaic acid, phthalic acid, and ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, etc. Examples include polyesters obtained from dihydric alcohols. The (co) polymer is a general term for a homopolymer and a copolymer. These plasticizers may be used alone or in combination of two or more.

  The molecular weight or number average molecular weight of these plasticizers is preferably 400 to 15,000, more preferably 800 to 10,000, and more preferably 1,000 to 8,000. Such a plasticizer may or may not have a functional group other than the active energy ray-curable group (for example, a hydroxyl group, a carboxyl group, a halogen group, etc.). When the molecular weight or number average molecular weight of the plasticizer is 400 or more, the plasticizer does not flow out from the cured product of the active energy ray-curable composition over time, and the initial physical properties can be maintained for a long time. Moreover, when the molecular weight or number average molecular weight of the plasticizer is 15,000 or less, the handleability of the active energy ray-curable composition tends to be improved.

  When the plasticizer is contained in the active energy ray-curable composition, the content thereof is preferably 5 to 150 parts by mass with respect to 100 parts by mass of the (meth) acrylic block copolymer of the present invention, and 10 to 120. A mass part is more preferable, and 20-100 mass parts is further more preferable. By adjusting the amount to 5 parts by mass or more, effects such as physical property adjustment and property adjustment become remarkable, and by setting the amount to 150 parts by mass or less, a cured product obtained by curing the active energy ray-curable composition is excellent in mechanical strength. Tend.

  The purpose of including the tackifier in the active energy ray-curable composition is to impart tackiness to a cured product obtained from the active energy ray-curable composition, for example. Examples of the tackifier include coumarone / indene resin, phenol resin, pt-butylphenol / acetylene resin, phenol / formaldehyde resin, xylene / formaldehyde resin, aromatic hydrocarbon resin, aliphatic hydrocarbon resin (terpene resin, etc.) Styrene resin (polystyrene, poly-α-methylstyrene, etc.), polyhydric alcohol ester of rosin, hydrogenated rosin, hydrogenated wood rosin, ester of hydrogenated rosin and monoalcohol or polyhydric alcohol, turpentine tackifying resin And the like. Among these, aliphatic hydrocarbon resins, polyhydric alcohol esters of rosin, hydrogenated rosins, hydrogenated wood rosins, and esters of hydrogenated rosins and monoalcohols or polyhydric alcohols are preferred.

  When the tackifier is contained in the active energy ray-curable composition, the content thereof is preferably 5 to 150 parts by mass with respect to 100 parts by mass of the (meth) acrylic block copolymer of the present invention. 120 mass parts is more preferable, and 20-100 mass parts is further more preferable. By setting it as 5 mass parts or more, the adhesiveness of hardened | cured material becomes remarkable, and the softness | flexibility of hardened | cured material tends to be more excellent by setting it as 150 mass parts or less.

  The additive having no active energy ray-curable group may be an organic compound or an inorganic compound.

  The active energy ray used when curing the (meth) acrylic block copolymer of the present invention or the active energy ray-curable composition containing the (meth) acrylic block copolymer is a known apparatus. Can be used for irradiation. In the case of an electron beam (EB), the acceleration voltage is suitably 0.1 to 10 MeV, and the irradiation dose is suitably 1 to 500 kGy.

For the ultraviolet irradiation, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, an LED, or the like that emits light having a wavelength range of 150 to 450 nm can be used. Integrated light quantity of the active energy ray is typically in the range of 10~20,000mJ / cm ^2, preferably in the range of 30~5,000mJ / cm ^2. If it is less than 10 mJ / cm ² , the curability of the (meth) acrylic block copolymer tends to be insufficient, and if it exceeds 20,000 mJ / cm ² , the (meth) acrylic block copolymer may deteriorate. There is.

  When the active energy ray is irradiated to the (meth) acrylic block copolymer of the present invention or the active energy ray-curable composition containing the (meth) acrylic block copolymer, the relative humidity is ( From the viewpoint of suppressing the decomposition of the (meth) acrylic block copolymer, it is preferably 30% or less, and more preferably 10% or less.

  For the (meth) acrylic block copolymer of the present invention or the active energy ray-curable composition containing the (meth) acrylic block copolymer, further necessary during or after irradiation with active energy rays. Accordingly, heating can be performed to accelerate curing. Such heating temperature is preferably within the range of 40 to 130 ° C, and more preferably within the range of 50 to 100 ° C.

  The viscosity of the active energy ray-curable composition containing the (meth) acrylic block copolymer of the present invention is preferably in the range of 0.1 to 1,000 Pa · s, preferably 0.1 to 100 Pa · s. More preferably, it is in the range of s, and even more preferably in the range of 0.1 to 20 Pa · s. The viscosity is measured by using a viscosity / viscoelasticity measuring device (HAAKE, MARS III) to form a coating film by dropping 1 g of the composition onto a φ35 mm, 1 ° inclined cone plate, and a steady flow viscosity as a measurement mode. The measurement mode may be used, and measurement may be performed under the conditions of a measurement temperature of 25 ° C., a measurement gap of 0.05 mm, and a shear rate of 1 (1 / s).

The storage elastic modulus after curing the active energy ray-curable composition containing the (meth) acrylic block copolymer of the present invention is preferably 1.0 × 10 ⁵ Pa or less. It is more preferable that it is × 10 ⁴ Pa or less, and it is more preferable that it is 3.5 × 10 ³ Pa or less. The storage elastic modulus is measured by using a viscosity / viscoelasticity measuring device (HAAKE, MARS III) by dropping 1 g of the composition onto a φ20 mm parallel plate, forming an uncured coating film, and moving as a measurement mode. 10 to 70 from the start of measurement at an irradiation intensity of 200 mW / cm ² using an optical S2000 manufactured by Lumen Dynamics under the conditions of a measurement temperature of 25 ° C., a measurement gap of 0.3 mm, and a measurement frequency of 1 Hz. What is necessary is just to measure by irradiating the active energy ray-curable composition by irradiating ultraviolet rays for a time of seconds.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to this Example.

  In the following Examples and Comparative Examples, the raw materials were dried and purified by a conventional method, deaerated with nitrogen, and transferred and supplied under a nitrogen atmosphere.

[Monomer consumption rate]
The consumption rate of each monomer after polymerization in the following Examples and Comparative Examples was obtained by collecting 0.5 mL of the reaction solution and mixing it in 0.5 mL of methanol, and then extracting 0.1 mL from the mixture solution. ¹ H-NMR measurement was carried out under the following measurement conditions after dissolving in 0.5 mL of deuterated chloroform and derived from the proton directly connected to the carbon-carbon double bond of the (meth) acrylic acid ester used as the monomer. Change in the ratio of integral values of the peak (chemical shift value 5.79 to 6.37 ppm) and the peak derived from the proton directly linked to the aromatic ring of toluene used as the solvent (chemical shift value 7.00 to 7.38 ppm) Calculated from
⁽¹ H-NMR measurement conditions)
Apparatus: Nuclear magnetic resonance apparatus "JNM-ECX400" manufactured by JEOL Ltd.
Temperature: 25 ° C

[Number average molecular weight (Mn), molecular weight distribution (Mw / Mn)]
In the following examples and comparative examples, GPC (gel permeation chromatography) measurement of the obtained polymer was performed under the following measurement conditions, and the number average molecular weight (Mn) and molecular weight distribution (Mw / The value of Mn) was determined.
(GPC measurement conditions)
Equipment: GPC equipment “HLC-8220GPC” manufactured by Tosoh Corporation
Separation column: “TSKgel SuperMultipore HZ-M (column diameter = 4.6 mm, column length = 15 cm)” manufactured by Tosoh Corporation (used by connecting two in series)
Eluent: Tetrahydrofuran Eluent flow rate: 0.35 mL / min Column temperature: 40 ° C
Detection method: differential refractive index (RI)

[Example 1]
(Process (1))
After adding 1.30 kg of toluene to a 3 L flask whose interior is dried and purged with nitrogen, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine is added as a Lewis base while stirring the solution in the flask. After sequentially adding 1.3 g and 24 g of a toluene solution containing 26% by mass of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as an organoaluminum compound, the mixture was cooled to −30 ° C. To this was added 4.6 g of a cyclohexane solution containing 10% by mass of sec-butyllithium as an organolithium compound, and then 1,1-dimethylpropane-1,3-diol dimethacrylate (hereinafter abbreviated as DMA) as a monomer. ) 32.2 g of a mixture of 1.7 g, 27 g of methyl methacrylate (hereinafter abbreviated as MMA) and 3.5 g of 2-ethylhexyl methacrylate (hereinafter abbreviated as 2-EHMA) was added all at once, and anionic polymerization was performed. Started. Subsequently, the reaction solution was stirred at −30 ° C. for 12 hours, and the reaction solution was sampled.
The consumption rate of DMA, MMA and 2-EHMA in step (1) was 100%.

(Process (2))
Subsequently, 570 g of 2-ethylhexyl acrylate (hereinafter abbreviated as 2-EHA) as a monomer was added at a rate of 6 g / min while stirring the reaction solution at −30 ° C. The reaction solution was sampled immediately after completion of the monomer addition.
The consumption rate of 2-EHA in the step (2) was 100%.

(Process (3))
Subsequently, while stirring the reaction solution at −30 ° C., 28.5 g of a mixture of DMA 1.5 g, MMA 24 g, and 2-EHMA 3.0 g as monomers were added all at once, and then the temperature was raised to 25 ° C. The reaction mixture was sampled 300 minutes after the addition of the mixture.
The consumption rate of DMA, MMA and 2-EHMA in the step (3) was 100%.

(Process (4))
Subsequently, while stirring the reaction solution at 25 ° C., 40 g of methanol was added to stop the anionic polymerization, and the methacrylic polymer block (A) -acrylic polymer block (B) -methacrylic polymer block (A). A solution containing a (meth) acrylic block copolymer which was a triblock copolymer bonded in the order of (A-B-A) was obtained. The (meth) acrylic block copolymer sampled from this solution had a Mn of 74,000 and Mw / Mn of 1.06.

(Process (5))
Next, the obtained solution was poured into 5,000 g of methanol to precipitate an oily precipitate. After collecting the oily precipitate, it was dried to obtain 580 g of a (meth) acrylic block copolymer (hereinafter referred to as “(meth) acrylic block copolymer <1>”).

(Process (6))
Next, for 50 g of (meth) acrylic block copolymer <1>, 50 g of n-octyl acrylate as a reactive diluent and 1-hydroxycyclohexyl phenyl ketone (produced by Ciba Specialty Chemicals) as a photopolymerization initiator , Irgacure (registered trademark) 184) was added, stirred and dissolved to obtain 101 g of an active energy ray-curable composition.

The physical properties of the (meth) acrylic block copolymer <1> were measured by the method described later.
The (meth) acrylic block copolymer <1> is a triblock copolymer bonded in the order of (A-B-A), and the total content of the two methacrylic polymer blocks (A) is The content of 11% by mass and the polymer block (B) was 89% by mass. Of the two methacrylic polymer blocks (A), the content of the structural unit derived from 2-EHMA in the methacrylic polymer block (A) produced by the step (1) is 6.0 mol%, The content of the structural unit derived from 2-EHMA in the methacrylic polymer block (A) produced by the step (3) was 5.8 mol%. The content of structural units derived from 2-EHMA when the total of the two methacrylic polymer blocks (A) was taken as a whole was 5.9 mol%.
Further, the viscosity was 3.3 Pa · s, the curing rate was good, the A evaluation, and the storage elastic modulus was 2.9 × 10 ³ Pa.
The results are shown in Table 2.

[Example 2, Comparative Examples 1 and 2]
A (meth) acrylic block was produced in the same manner as in Example 1 except that the amounts of DMA, MMA, 2-EHMA, and 2-EHA used in steps (1) to (3) were changed as shown in Table 1. A copolymer was obtained. The (meth) acrylic block copolymer obtained in Example 2 is referred to as (meth) acrylic block copolymer <2>, and the (meth) acrylic block obtained in Comparative Examples 1 and 2 was used. The copolymers are referred to as (meth) acrylic block copolymers <3> and <4>, respectively.
Furthermore, each active energy ray-curable composition containing each (meth) acrylic block copolymer <2> to <4> was obtained by the same method as in Example 1.

[viscosity]
The viscosity of the (meth) acrylic block copolymers obtained in the above Examples and Comparative Examples was evaluated by the following method using a viscosity / viscoelasticity measuring apparatus (MARS III, manufactured by HAAKE).
1 g of a 1: 1 (weight ratio) mixture of the (meth) acrylic block copolymer and n-octyl acrylate obtained in the above Examples and Comparative Examples was dropped on a φ35 mm, 1 ° inclined cone plate, A coating film was formed. The steady flow viscosity measurement mode was used as the measurement mode, and the viscosity (Pa · s) was measured under the conditions of a measurement temperature of 25 ° C., a measurement gap of 0.05 mm, and a shear rate of 1 (1 / s).

[Curing speed]
The curing speed of the (meth) acrylic block copolymer obtained in the above examples and comparative examples is determined by the following method of the active energy ray-curable composition containing the (meth) acrylic block copolymer. It evaluated by the presence or absence of the bleed-out of the liquid material from hardened | cured material.
The active energy ray-curable compositions obtained in the above examples and comparative examples were applied on glass so as to have a thickness of 150 μm, and irradiated with ultraviolet rays so as to have an integrated dose of 200 mJ / cm ² in the atmosphere. The active energy ray-curable composition was cured. The obtained cured product was touched with a finger at room temperature of 25 ° C. and evaluated according to the following criteria.
A: Liquid does not adhere to fingers (no bleed out)
B: Liquid adheres to fingers (with bleed out)

[Storage modulus]
The storage elastic modulus, which is an index of the flexibility of the cured product of the (meth) acrylic block copolymer obtained in the above examples and comparative examples, was measured by the following method using a viscosity / viscoelasticity measuring device (HAAKE, MARS). III).
1 g of the active energy ray-curable composition obtained in the above Examples and Comparative Examples was dropped on a parallel plate having a diameter of 20 mm to form an uncured coating film. Measurement using dynamic viscoelasticity measurement mode as measurement mode, measurement temperature 25 ° C., measurement gap 0.3 mm, measurement frequency 1 Hz, using Lumin Dynamics's Omniture S2000 as the light source, and starting measurement at irradiation intensity 200 mW / cm ² The active energy ray-curable composition was cured by irradiating with ultraviolet rays for 10 to 70 seconds, and the storage elastic modulus (Pa) after curing was measured.

  As can be seen from Table 2, the (meth) acrylic block copolymers of Comparative Examples 1 and 2 are methacrylic acid alkyl esters having an alkyl group having 4 or more carbon atoms that do not have an active energy ray-curable group. Since the methacrylic polymer block (A) does not contain the monomer unit (a2) derived from 2-EHMA, in Comparative Example 1, the (meth) acrylic block copolymer and hence the active energy ray curing containing it. The composition is excellent in the curing speed, but has a high viscosity, and the cured product of the active energy ray-curable composition containing the (meth) acrylic block copolymer has a high storage elastic modulus and low flexibility. Inferior. In Comparative Example 2 in which the content of the acrylic polymer block (B) is increased as compared with Comparative Example 1, the viscosity of the (meth) acrylic block copolymer and thus the active energy ray-curable composition containing it is low. The cured product has a low storage elastic modulus, so that it has excellent flexibility but is inferior in that the curing rate is low.

  On the other hand, the methacrylic polymer block (A) of Examples 1 and 2 contains a monomer unit (a2) derived from 2-EHMA as the monomer unit (a2), and has a low viscosity. And it is excellent in the curing rate of the active energy ray-curable composition containing the (meth) acrylic block copolymer and the flexibility of the cured product.

  Therefore, the (meth) acrylic block copolymer of the present invention is excellent in coating property due to its low viscosity, and is excellent in the curing speed and flexibility of the cured product. It is useful for applications such as coating materials.

Claims (5)

A methacrylic polymer block (A) having an active energy ray-curable group containing a partial structure represented by the following general formula (1), an acrylic polymer block (B) having no active energy ray-curable group, and Containing
The methacrylic polymer block (A) is a methacrylic acid alkyl ester having a monomer unit (a1) derived from methyl methacrylate and an alkyl group having 4 or more carbon atoms that does not have an active energy ray-curable group. A (meth) acrylic block copolymer containing the derived monomer unit (a2).

(In the formula (1), ^{R 1} represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.)   The (meth) acrylic block copolymer according to claim 1, wherein the alkyl methacrylate has a glass transition temperature (Tg2) of a homopolymer of 50 ° C or lower.   The (meta) according to claim 1 or 2, wherein the content of the monomer unit (a2) with respect to all monomer units forming the methacrylic polymer block (A) is 0.1 to 30 mol%. ) Acrylic block copolymer.   An active energy ray-curable composition containing the (meth) acrylic block copolymer according to claim 1. The hardened | cured material of the (meth) acrylic block copolymer in any one of Claims 1-3, or the hardened | cured material of the active energy ray curable composition of Claim 4.