KR101114638B1 - Pressure-sensitive adhesive composition and adhesive sheet and adhesive optical component using the same - Google Patents

Abstract

The present invention provides a pressure-sensitive adhesive composition having both durability and light leakage prevention property, and an adhesive sheet and an adhesive optical member using the same. Specifically, the present invention relates to a copolymer (A) obtained by copolymerizing (i) a (meth) acrylic acid ester and a functional group-containing monomer, and (ii) a radically polymerizable monomer having at least one isocyanate group in the (meth) acrylic acid ester and a molecule. The pressure-sensitive adhesive composition containing the copolymer (B) obtained by copolymerizing the above, and the pressure-sensitive adhesive sheet and the pressure-sensitive optical member using the same are provided.

Durability, light leakage prevention, pressure-sensitive adhesive composition, pressure-sensitive adhesive sheet, adhesive optical member, (meth) acrylic acid ester, isocyanate, radical polymerizable monomer

Description

PRESSURE-SENSITIVE ADHESIVE COMPOSITION AND ADHESIVE SHEET AND ADHESIVE OPTICAL COMPONENT USING THE SAME

The present invention relates to a pressure-sensitive adhesive composition, and an adhesive sheet and an adhesive optical member using the same.

The design of the pressure sensitive adhesive composition for optical functional films has responded by increasing the amount of the crosslinking agent so that defects such as floating and peeling do not occur in endurance tests such as heat resistance and heat and moisture resistance. However, there has been a problem that the light leakage preventing property (white spot) is deteriorated by increasing the amount of the crosslinking agent. Conversely, reducing the amount of crosslinking agent improves light leakage prevention, but lowers durability. Therefore, successful compatibility of durability and light leakage prevention is difficult.

In order to solve this problem, it is known to use a polyfunctional isocyanate compound as a crosslinking agent (see Japanese Patent Laid-Open No. 2001-262103). However, the structure of these compounds is a structure in which the compound which has several isocyanate group in one molecule, such as hexamethylene diisocyanate and toluylene-2, 4- diisocyanate, was added to the terminal of a polyol or polyester skeleton. When these compounds are added to the (meth) acrylic acid ester copolymer which becomes a main component of a pressure-sensitive adhesive agent, from the viewpoint of the compatibility of the skeleton of the (meth) acrylic acid ester copolymer and the skeleton of the crosslinking agent, the compatibility deteriorates depending on the addition amount and the coating liquid. Problems such as clouding or bleeding of crosslinkers have arisen.

An object of the present invention is to provide a pressure-sensitive adhesive composition having both durability and light leakage prevention property, and an adhesive sheet and an adhesive optical member using the same.

The present invention includes the following inventions.

(1) copolymer (A) obtained by copolymerizing (i) a (meth) acrylic acid ester and a functional group-containing monomer, and (ii) copolymerizing a radical polymerizable monomer having at least one isocyanate group in the (meth) acrylic acid ester and a molecule. The pressure sensitive adhesive composition containing the copolymer (B) obtained.

(2) The pressure-sensitive adhesive composition according to the above (1), wherein the weight average molecular weight of the copolymer (A) is 500,000 to 2 million (polystyrene equivalent value measured by GPC).

(3) The pressure-sensitive adhesive composition according to (1) or (2), wherein the weight average molecular weight of the copolymer (B) is 50,000 to 1.2 million (polystyrene equivalent value measured by GPC).

(4) Pressure sensitive adhesive composition in any one of said (1)-(3) containing 0.1-30 weight part of copolymers (B) per 100 weight part of copolymers (A).

(5) The pressure-sensitive adhesive composition according to any one of the above (1) to (4), which is used for the optical member.

(6) A pressure-sensitive adhesive sheet, wherein a layer containing the pressure-sensitive adhesive composition according to any one of the above (1) to (5) is provided on at least one side of the base sheet.

(7) A pressure-sensitive adhesive optical member comprising, on at least one side of a sheet-like optical member, a layer comprising the pressure-sensitive adhesive composition according to any one of the above (1) to (5).

(8) The adhesive optical member according to the above (7), wherein the sheet-like optical member is a polarizing plate or a retardation plate.

The pressure-sensitive adhesive composition of the present invention is characterized by using a copolymer (B) as a crosslinking agent. Copolymer (B) is a polymer having a skeleton similar to that of Copolymer (A) obtained by copolymerizing a (meth) acrylic acid ester and a functional group-containing monomer used as a main component of a pressure-sensitive adhesive, and at least one in the (meth) acrylic acid ester and a molecule. It is obtained by copolymerizing the radically polymerizable monomer which has an isocyanate group. Thereby, defects such as bleeding of the crosslinking agent can be avoided and both durability and light leakage prevention can be successfully achieved.

The (meth) acrylic acid ester used in the above copolymers (A) and (B) is not particularly limited, and the substituents (for example, alkyl groups, aralkyl groups, aryl groups, alkoxyalkyl groups) forming the ester moiety are not particularly limited. (Meth) acrylic acid ester having 1 to 20 carbon atoms, preferably 1 to 18 carbon atoms. Examples of such (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, and (meth) acrylic acid Cyclohexyl, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, palmitic (meth) acrylate And methyl, stearyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, methoxyethyl (meth) acrylate, and the like. These (meth) acrylic acid esters may be used independently and may be used in combination of 2 or more type.

The functional group-containing monomer used in the copolymer (A) is not particularly limited as long as it provides a crosslinking point that can be crosslinked by the copolymer (B) used as a crosslinking agent, and for example, has a functional group having active hydrogen. A monomer can be mentioned. Examples of the monomer having a functional group having active hydrogen include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. Hydroxyl group-containing monomers such as 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and allyl alcohol; Acrylamides such as acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-methylol acrylamide, and N-methylol methacrylamide; (Meth) acrylic acid monoalkylaminoalkyl, such as monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, and monoethylaminopropyl (meth) acrylate; And ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These monomers may be used independently and may be used in combination of 2 or more type.

The ratio of the (meth) acrylic acid ester to the functional group-containing monomer used in the preparation of the copolymer (A) is usually 99.9: 0.1 to 80:20 by weight ratio, preferably 99: 1 to 90:10.

In addition to the (meth) acrylic acid ester and the functional group-containing monomer, other monomers may be used for the copolymer (A), depending on the purpose. Examples of "other" monomers used for this purpose include vinyl esters such as vinyl acetate and vinyl propionate; Olefins such as ethylene, propylene and isobutylene; Halogenated olefins such as vinyl chloride and vinylidene chloride; Styrene monomers such as styrene and α-methylstyrene; Diene monomers such as butadiene, isoprene and chloroprene; Nitrile monomers such as acrylonitrile and methacrylonitrile; N, N-dialkyl substituted acrylamides, such as N, N- dimethyl acrylamide and N, N- dimethyl methacrylamide, etc. are mentioned. These may be used independently and may be used in combination of 2 or more type. The usage-amount of the "other" monomer used according to these objectives is 0-20 weight part normally per 100 weight part of all the monomers which comprise the said copolymer (A), Preferably it is 0-10 weight part or less.

In the pressure-sensitive adhesive composition of the present invention, the copolymerization form of the copolymer (A) is not particularly limited, and may be any of random, block, and graft copolymers. Moreover, in molecular weight, it is preferable that weight average molecular weight exists in the range of 500,000-2 million. When the said weight average molecular weight is less than 500,000, there exists a possibility that adhesive durability may become inadequate. If the weight average molecular weight exceeds 2 million, it will cause the followability to stretch of the substrate to decrease. In consideration of adhesiveness, adhesion durability, and following properties of stretching of the substrate, the weight average molecular weight is preferably 800,000 to 1.8 million, particularly preferably 1.2 million to 1.7 million. In addition, the said weight average molecular weight is the polystyrene conversion value measured by the gel permeation chromatography (GPC) method. In the present invention, one type of copolymer (A) may be used, or two or more types may be used in combination.

As a radically polymerizable monomer which has at least 1 isocyanate group in a molecule | numerator used for the said copolymer (B), if it gives a function as a crosslinking agent to the said copolymer (B), it will not specifically limit. Examples of such radically polymerizable monomers include (meth) acrylic acid ester derivatives having at least one isocyanate group (eg, (meth) acrylic acid 2-isocyanatoethyl, (meth) acrylic acid, (meth) acrylic acid 2- Radical polymerizable monomers having a carboxyl group or a hydroxyl group such as hydroxyethyl and 4-hydroxybutyl (meth) acrylate and a polyfunctional isocyanate compound such as toluene diisocyanate and xylylene diisocyanate) Can be mentioned. These may be used independently and may be used in combination of 2 or more type.

The ratio of the (meth) acrylic acid ester used in the preparation of the copolymer (B) to the radically polymerizable monomer having at least one isocyanate group in the molecule is usually 99.9: 0.1 to 80:20 by weight, preferably 99: 1. To 90:10.

In addition to the (meth) acrylic acid ester and the radically polymerizable monomer having at least one isocyanate group in the molecule, other copolymers may be used for the copolymer (B) depending on the purpose. Examples of "other" monomers used for this purpose include vinyl esters such as vinyl acetate and vinyl propionate; Olefins such as ethylene, propylene and isobutylene; Halogenated olefins such as vinyl chloride and vinylidene chloride; Styrene monomers such as styrene and α-methylstyrene; Diene monomers such as butadiene, isoprene and chloroprene; Nitrile monomers such as acrylonitrile and methacrylonitrile; N, N-dialkyl substituted acrylamides, such as N, N- dimethyl acrylamide and N, N- dimethyl methacrylamide, etc. are mentioned. These may be used independently and may be used in combination of 2 or more type. The usage-amount of the "other" monomer used according to these objectives is 0-10 weight part normally per 100 weight part of all the monomers which comprise the said copolymer (B), Preferably it is 0-5 weight part.

In the pressure-sensitive adhesive composition of the present invention, the copolymerization form of the copolymer (B) is not particularly limited, and may be any of random, block, and graft copolymers. In addition, in molecular weight, it is preferable that weight average molecular weight exists in the range of 50,000-2,200,000 (polystyrene conversion value measured by GPC). If the weight average molecular weight is less than 50,000, the cohesive force of the pressure-sensitive adhesive is not obtained and durability is poor. When the weight average molecular weight exceeds 1.2 million, the viscosity rise of the coating liquid becomes remarkable and the coating suitability is inferior. In consideration of these, the weight average molecular weight is more preferably 100,000 to 1 million, particularly preferably 150,000 to 950,000. In the present invention, one type of copolymer (B) may be used, or two or more types may be used in combination. In addition, the compounding ratio of copolymer (A) and copolymer (B) is 0.1-30 weight part of copolymers (B) normally per 100 weight part of copolymers (A), Preferably it is 0.5-15 weight part.

The polymerization for producing the copolymer (A) and the copolymer (B) is performed by a conventional polymerization method such as solution polymerization or bulk polymerization. The reaction temperature of polymerization is 50-85 degreeC normally, Preferably it is 55-80 degreeC.

In the case of solution polymerization, the monomer is usually 0.5 to 60% by weight, preferably 5 to 50% by weight of azobisisobuty in a solid content concentration in a solvent such as acetone, benzene, toluene, ethyl acetate, hexane, heptane and isopropanol. The polymerization is carried out using a polymerization initiator such as nitrile or benzoyl peroxide. The compounding quantity of a polymerization initiator is 0.05-1 weight part normally with respect to 100 weight part of monomer total amounts.

To the pressure-sensitive adhesive composition of the present invention, various known additives that are conventionally used in pressure-sensitive adhesive compositions according to the purpose, for example, plasticizers, silane coupling agents, ultraviolet absorbers, antioxidants, etc., are added to the pressure-sensitive adhesive composition of the present invention. can do.

The pressure sensitive adhesive composition of this invention is suitable for the optical member.

When the pressure-sensitive adhesive composition of the present invention is used for an optical member, it is particularly advantageous for the composition to have light transparency.

The adhesive sheet of this invention contains the layer (henceforth abbreviated as an "adhesive layer") containing the said pressure sensitive adhesive composition on at least one surface of a base material sheet. Examples of the substrate sheet include paper substrates such as glassine paper, coated paper, cast coated paper, laminated papers in which thermoplastic resins such as polyethylene are laminated on these paper substrates, polyethylene terephthalate films, and polybutylene terephthalate films. Polyester films such as polyethylene naphthalate films, polyolefin films such as polypropylene and polymethylpentene, polycarbonate films, plastic films such as cellulose acetate films, and laminated sheets containing these films. have. The base sheet is appropriately selected according to the use of the adhesive sheet. The adhesive sheet of this invention can be used as a member for transferring an adhesive layer to a to-be-adhered body, and can also be used as a member for attaching the said adhesive sheet to a desired to-be-adhered body. When using an adhesive sheet for the former use, peeling agents, such as a silicone resin, are apply | coated normally to a base material sheet. In this case, the thickness of the base sheet is not particularly limited, but is usually about 20 to 150 µm. When using an adhesive sheet for the latter use, the kind and thickness of a base material sheet are selected according to the use. In addition, in this case, a normal release sheet can be provided on an adhesive layer according to the objective. In the adhesive sheet of this invention, the thickness of an adhesive layer is about 5-150 micrometers normally, Preferably it is about 10-90 micrometers.

Next, the adhesive optical member of the present invention is provided with a layer containing the pressure-sensitive adhesive composition on at least one side of the sheet-like optical member. Although the said sheet-like optical member is not specifically limited, For example, a polarizing plate, a retardation plate, an antireflection plate, a viewing angle expansion film is mentioned. Among these, a polarizing plate is especially preferable. Examples of the polarizing plate include liquid crystal display devices, light amount adjustments, polarization interference application devices, and optical defect detectors. Among these, it is advantageous to provide the said adhesive layer in the polarizing plate for liquid crystal cells in a liquid crystal display device especially.

<Examples>

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, these do not limit the scope of the present invention at all.

In addition, the weight average molecular weight of the polymer was measured as follows.

(Measurement method of weight average molecular weight)

Three consecutive samples containing HLC-8020 (columns TSKgel GMH _XL , TSKgel GMH _XL , TSKgel G2000H _XL ) manufactured by TOSOH CORPORATION using a solution of 1% by weight of polymer in tetrahydrofuran (THF) as a sample. Column), and the weight average molecular weight was measured under the conditions of 40 ℃, 1 ml / min THF solvent.

&Lt; Reference Example 1 &

99 parts by weight of n-butyl acrylate, 1 part by weight of 4-hydroxybutyl acrylate, and 0.2 part by weight of azobisisobutyronitrile as a polymerization initiator were added in 200 parts by weight of ethyl acetate. The solution was stirred at 60 ° C. for 17 hours to obtain a acrylic acid ester copolymer solution having a weight average molecular weight of 1.6 million.

<Reference Example 2>

99 parts by weight of n-butyl acrylate, 1 part by weight of 2-isocyanatoethyl methacrylic acid, and 0.2 part by weight of azobisisobutyronitrile as a polymerization initiator were added in 200 parts by weight of ethyl acetate. The solution was stirred at 60 ° C for 17 hours to obtain an acrylic acid ester copolymer solution having a weight average molecular weight of 850,000.

Reference Example 3

95 parts by weight of n-butyl acrylate, 5 parts by weight of 2-isocyanatoethyl methacrylic acid, and 0.2 part by weight of azobisisobutyronitrile as a polymerization initiator were added in 200 parts by weight of ethyl acetate. By stirring this solution at 60 degreeC for 17 hours, the acrylic acid ester copolymer solution of the weight average molecular weight 920,000 was obtained.

Reference Example 4

90 parts by weight of n-butyl acrylate, 10 parts by weight of 2-isocyanatoethyl methacrylic acid, and 0.2 part by weight of azobisisobutyronitrile as a polymerization initiator were added in 200 parts by weight of ethyl acetate. By stirring this solution at 60 degreeC for 17 hours, the acrylic acid ester copolymer solution of the weight average molecular weight 900,000 was obtained.

Reference Example 5

90 parts by weight of n-butyl acrylate, 10 parts by weight of 2-isocyanatoethyl methacrylic acid, and 0.5 part by weight of azobisisobutyronitrile as a polymerization initiator were added in 200 parts by weight of ethyl acetate. The solution was stirred at 60 ° C. for 17 hours to obtain an acrylic ester copolymer solution having a weight average molecular weight of 410,000.

Reference Example 6

90 parts by weight of n-butyl acrylate, 10 parts by weight of 2-isocyanatoethyl methacrylic acid, and 0.2 parts by weight of azobisisobutyronitrile as a polymerization initiator were added in 100 parts by weight of ethyl acetate and 100 parts by weight of toluene. The solution was stirred at 60 ° C. for 17 hours to obtain an acrylic acid ester copolymer solution having a weight average molecular weight of 180,000.

&Lt; Example 1 >

11.0 parts by weight of the copolymer obtained in Reference Example 2 was added to 100 parts by weight of the copolymer obtained in Reference Example 1. This solution was diluted with ethyl acetate so as to be a solution having a concentration of 25% to obtain a pressure-sensitive adhesive A.

<Example 2>

2.02 parts by weight of the copolymer obtained in Reference Example 3 was added to 100 parts by weight of the copolymer obtained in Reference Example 1. This solution was diluted with ethyl acetate so that it might become a solution of concentration 25%, and it was set as adhesive B.

<Example 3>

1.00 parts by weight of the copolymer obtained in Reference Example 4 was added to 100 parts by weight of the copolymer obtained in Reference Example 1. This solution was diluted with ethyl acetate so that it might become a solution of concentration 25%, and it was set as adhesive C.

<Example 4>

1.00 parts by weight of the copolymer obtained in Reference Example 5 was added to 100 parts by weight of the copolymer obtained in Reference Example 1. This solution was diluted with ethyl acetate so that it might become a solution of concentration 25%, and it was set as adhesive D.

Example 5

1.00 parts by weight of the copolymer obtained in Reference Example 6 was added to 100 parts by weight of the copolymer obtained in Reference Example 1. This solution was diluted with ethyl acetate so that it might become a solution of concentration 25%, and it was set as adhesive E.

Comparative Example 1

2.50 parts by weight of xylylene diisocyanate-based trifunctional adduct (Soken Chemical & Engineering Co., Ltd .: TD-75) was added to 100 parts by weight of the copolymer obtained in Reference Example 1. . This solution was diluted with ethyl acetate so that it might become a solution of concentration 25%, and it was set as adhesive F.

Comparative Example 2

0.50 parts by weight of xylylenediisocyanate-based trifunctional adduct (Soda Chemical Co., Ltd. product: TD-75) was added to 100 parts by weight of the copolymer obtained in Reference Example 1. This solution was diluted with ethyl acetate so that it might become a solution of concentration 25%, and it was set as adhesive G.

Comparative Example 3

0.10 part by weight of xylylenediisocyanate-based trifunctional adduct (Soda Chemical Co., Ltd. product: TD-75) was added to 100 parts by weight of the copolymer obtained in Reference Example 1. This solution was diluted with ethyl acetate so as to be a solution having a concentration of 25% to obtain a pressure-sensitive adhesive H.

<Comparative Example 4>

0.75 weight part of isophorone diisocyanate type bifunctional adducts (made by MITSUBISHI CHEMICAL CORPORATION: NY-T-35C) were added to 100 weight part of copolymers obtained by the reference example 1. This solution was diluted with ethyl acetate so that it might become a solution of concentration 25%, and it was set as adhesive I.

Each adhesive prepared in the above Examples and Comparative Examples was made of a polyethylene terephthalate film (LINTEC Corporation) having a thickness of 38 μm, which is a transfer member provided with a release layer of a silicone resin on one side by a knife coater. It applied to the silicone resin peeling process surface of SP-PET3811). The surface coated with the pressure-sensitive adhesive was dried at 90 ° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 25 μm. Next, the adhesive layer surface of the said transfer member was laminated | stacked on the polarizing plate, and the polarizing plate with an adhesive layer to which the transfer member was temporarily stuck was obtained. The compatibility, durability, and light leakage prevention property of the obtained polarizing plate were tested as follows. The results are shown in Table 1 below.

1) Compatibility: The coating film thus prepared and the dried film after application to the transfer member were visually observed.

(○: No change in appearance, ×: cloudiness, whitening)

2) Durability: The adhesive layer surface of the adhesive polarizing plate (size 233 mm x 309 mm) which peeled the transcription | transfer member was stuck to the alkali free glass. Then, the glass was autoclaved and left to stand on 80 degreeC and dry conditions for 200 hours. The appearance change of the polarizing plate was visually evaluated.

(○: no defect, Δ: fine bubbles, ×: bubbles)

3) Light leakage prevention property: The surface of the adhesive layer of the adhesive polarizing plate (size 233 mm x 309 mm) with which the transcription | transfer member was peeled off was stuck to alkali free glass by cross nicol. Then, the glass was autoclaved and left to stand on 80 degreeC and dry conditions for 200 hours. The degree of light leakage was evaluated by the brightness difference as follows with MCPD-2000 manufactured by Otsuka Electronics Co., Ltd. (Otsuka Electronics Co., Ltd.).

4) Brightness difference: After measuring the brightness in the range of 1 cm inside and the brightness of the center of a polarizing plate from the edge part of the center part of the edge part of a polarizing plate, the difference between the average value of brightness of each side and the brightness of the center was calculated | required.

Compatibility ^{1) 2)} durable Light leakage prevention ³⁾ Coating liquid / dry coating 80 ℃ drying Brightness difference △ L * ⁴⁾ Example 1 Adhesive A ○ / ○ △ 1.24 Example 2: Adhesive B ○ / ○ ○ 1.13 Example 3: Adhesive C ○ / ○ ○ 0.85 Example 4: Adhesive D ○ / ○ ○ 1.58 Example 5: Adhesive E ○ / ○ ○ 1.92 Comparative Example 1: Adhesive F ○ / ○ Peeling Inmeasurement Comparative Example 2: Adhesive G ○ / ○ ○ 9.36 Comparative Example 3: Adhesive H ○ / ○ × 1.33 Comparative Example 4: Adhesive I × / × ○ 1.20

According to the present invention, it is possible to provide a pressure-sensitive adhesive composition having excellent durability and light leakage preventing property, and a pressure-sensitive adhesive sheet and a pressure-sensitive optical member using the same, while preventing white clouding and bleeding of the coating liquid.

Claims (9)

(i) a copolymer (A) obtained by copolymerizing a monomer having a functional group having an (meth) acrylic acid ester and an active hydrogen, and (ii) a radical polymerizable monomer having at least one isocyanate group in the (meth) acrylic acid ester and a molecule thereof. The pressure sensitive adhesive composition containing the copolymer (B) obtained by copolymerizing. The pressure sensitive adhesive composition of Claim 1 whose weight average molecular weights of a copolymer (A) are 500,000-2 million (polystyrene conversion value measured by GPC). The pressure-sensitive adhesive composition according to claim 1, wherein the weight average molecular weight of the copolymer (B) is 50,000 to 1.2 million (polystyrene equivalent value measured by GPC). The pressure-sensitive adhesive composition according to any one of claims 1 to 3, which contains 0.1 to 30 parts by weight of the copolymer (B) per 100 parts by weight of the copolymer (A). The pressure sensitive adhesive composition according to any one of claims 1 to 3, which is used for the optical member. The adhesive sheet in which the layer containing the pressure sensitive adhesive composition in any one of Claims 1-3 was provided in at least one side of a base material sheet. The adhesive optical member in which the layer containing the pressure sensitive adhesive composition in any one of Claims 1-3 was provided in at least one surface of the sheet-like optical member. The adhesive optical member according to claim 7, wherein the sheet-like optical member is a polarizing plate or a retardation plate. The pressure sensitive adhesive composition according to claim 1, wherein the monomer having a functional group having active hydrogen is a hydroxyl group-containing monomer.