TW201406790A - Photopolymerization resin composition and photopolymerization resin including the same - Google Patents

Abstract

The present invention provides a photopolymerizable resin comprising: a (meth)acrylic ester-based monomer; a cross-linkable functional group-containing monomer; and a thermal initiator capable of absorbing UV rays and having a 10 hour half-life temperature of 70 DEG C or less. In addition, the present invention provides a photopolymerizable resin prepared by polymerizing: a (meth)acrylic ester-based monomer; a cross-linkable functional group-containing monomer; and a thermal initiator capable of absorbing UV rays and having a 10 hour half-life temperature of 70 DEG C or less.

Description

Photopolymerizable resin composition and photopolymerizable resin comprising the photopolymerizable resin composition

The present invention relates to a photopolymerizable resin composition and a photopolymerizable resin comprising the photopolymerizable resin composition, and more particularly to a photopolymerization containing a thermal initiator capable of absorbing ultraviolet rays having a half-life temperature in a monomer of a specific composition. Resin composition.

The conventional thermosetting resin composition uses an organic solvent, but the organic solvent used will volatilize during the curing process, and there are environmental problems, and the curing procedure is long and the automatic program is complicated compared to the ultraviolet curing method. problem. Therefore, there has been a growing effort to develop an ultraviolet curable resin composition for improving the problems of the thermosetting resin composition currently used.

However, the ultraviolet curable resin composition of Korean Laid-Open Patent Publication No. 10-2006-0020098 contains an ultraviolet curable resin, an initiator, an ultraviolet reactive propylene or ethylene monomer, and an inorganic powder, but has a photoinitiator and heat. Since the mixture of the initiator is used as an initiator, the reaction proceeds while absorbing light energy. Therefore, in the photopolymerization of the ultraviolet curable resin composition, there is still a problem that it is difficult to adjust the reaction rate and the molecular weight.

In order to solve the above problems, an object of the present invention is to provide a photopolymerizable resin composition which does not cause excessive reaction heat due to reactivity of a monomer during photopolymerization, and can adjust a reaction rate and a molecular weight.

Further, in general, when a molecular weight modifier is used in a large amount, the molecular weight is lowered. Therefore, another object of the present invention is to provide a molecular weight regulator which can be used less. A photopolymerizable resin obtained by polymerizing a photopolymerizable resin composition having an increased molecular weight.

In order to achieve the above object, the photopolymerizable resin composition of the present invention comprises a (meth) acrylate monomer, a crosslinkable functional group-containing monomer, and a heat of ultraviolet rays having a half-life of 10 hours and a temperature of 70 ° C or less. Initiator.

Further, in order to achieve the above other object, the photopolymerizable resin of the present invention contains a (meth) acrylate monomer, a crosslinkable functional group-containing monomer, and an ultraviolet ray having a half-life of 10 hours and a temperature of 70 ° C or lower. The thermal initiator is polymerized.

The present invention contains a thermal initiator having a low half-life temperature capable of absorbing ultraviolet rays in the photopolymerizable resin composition, thereby being capable of being mildly reacted, and also capable of reacting heat during polymerization of the photopolymerizable resin composition due to the thermal initiator. Maintained low.

The embodiments described in detail below with reference to the drawings will make the advantages and features of the invention, and the methods of the inventions. However, the present invention is not limited to the embodiments disclosed below, and the present invention can be implemented in various ways that are different from each other. This embodiment is only used to make the disclosure of the present invention more complete and contribute to the technical field of the present invention. The scope of the present invention can be fully understood by a person skilled in the art, and the present invention is defined in accordance with the scope of the patent application. Throughout the specification, the same reference numerals denote the same structural elements.

Hereinafter, the present invention will be described in detail.

Photopolymerized resin composition

The present invention provides a photopolymerizable resin composition comprising: a (meth) acrylate monomer, a crosslinkable functional group-containing monomer, and a thermal initiator capable of absorbing an ultraviolet ray having a half-life of 10 hours and having a temperature of 70 ° C or lower.

The type of the above (meth) acrylate monomer is not particularly limited, and for example, an alkyl (meth) acrylate can be used. At this time, if the single The hydroxyl group contained in the body becomes an excessively long chain, the cohesive force of the photopolymerizable resin composition is lowered, and it is difficult to adjust the glass transition temperature (Tg) and the adhesion. Therefore, it is preferred to use a (meth) acrylate type. A body having an alkyl group having 1 to 14 carbon atoms.

Examples of such monomers include methyl (meth)acrylate, ethyl(meta)acrylate, and n-propyl (meth)acrylate (n). -propyl(meta)acrylate), isopropyl (meta)acrylate, n-butyl(meta)acrylate, tert-butyl (meth)acrylate (t-butyl(meta)acrylate), sec-butyl(meta)acrylate, pentyl(meta)acrylate,(meth)acrylic acid 2 2-ethylhexyl(meta)acrylate, 2-ethylbutyl(meta)acrylate, n-octyl(meth)acrylate (n-octyl() Meta)acrylate), iso-Octyl(meta)acrylate, isonyl (meta)acrylate, lauryl(meta)acrylate, and (meth)acrylic acid Tetradecyl (meta) acrylate, one or a mixture of two or more of the above may be used in the present invention.

When the photopolymerizable resin composition is formed, a crosslinking functional group-containing monomer may be added. In this case, the photopolymerizable resin composition to be formed in the present invention may be a polymer of a monomer mixture, the monomer mixture The polymer contains a (meth) acrylate monomer and a monomer having a crosslinkable functional group.

The crosslinkable functional group-containing monomer imparts a crosslinkable functional group capable of reacting with the polyfunctional crosslinking agent, and functions to adjust the durability reliability and cohesive force of the photopolymerizable resin composition. The crosslinkable functional group-containing monomer which can be used is, for example, a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and a nitrogen-containing monomer.

In the present invention, a hydroxyl group-containing monomer is preferably used in the crosslinkable functional group-containing monomer, but the present invention is not limited thereto. Examples of the above hydroxyl group-containing monomer are 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (meth)acrylic acid- 6-hydroxyhexyl ester, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate or 2-hydroxypropanediol (meth)acrylate, an example of a carboxyl group-containing monomer There are (meth)acrylic acid, 2-(meth)acryloxyacetic acid, 3-(meth)acryloxypropionic acid, 4-(A) Alkenyl oxybutyric acid, acrylic acid dimer, Itaconic acid, maleic acid or maleic anhydride, examples of nitrogen-containing monomers are methacrylamide (methacrylamide), N-vinylpyrrolidone or n-vinyl caprolactam, but the invention is not limited thereto. The present invention may use one or a mixture of two or more of the above.

Further, the photopolymerizable resin composition of the present invention may further contain a thermal initiator in addition to the (meth) acrylate monomer and the monomer having a cross-linking functional group. In the present invention, in order to stably form a photopolymerizable resin such as an acrylic resin, a thermal initiator having a half-life temperature is used. The thermal initiator acts as a substance which forms a radical by heat, and causes a chain polymerization reaction of a (meth) acrylate monomer and a monomer having a crosslinkable functional group. Further, at this time, the half life of the thermal initiator means the time required for the original amount of the initiator to be decomposed by half to form a radical.

In general, when a photopolymerizable resin is formed as a photopolymerizable resin composition, a photoinitiator is used, and the photoinitiator has no half life, and as long as it can absorb light energy, the reaction can be carried out, and thus it is difficult to control the heat of reaction. Therefore, instead of using a photoinitiator, a thermal initiator capable of absorbing ultraviolet rays is used, and the half-life temperature of the thermal initiator is limited to a low temperature, so that the heat of reaction can be controlled and a low heat generation temperature can be maintained, thereby making the whole The polymerization of the photopolymerized resin composition is kept slow.

The 10-hour half-life temperature of the thermal initiator is 70 ° C or lower, preferably 60 ° C or lower, more preferably 50 ° C or lower. On the other hand, the lower limit of the 10-hour half-life temperature of the thermal initiator in the present invention is not particularly limited. However, if the 10-hour half-life temperature is too low, a non-uniform curing reaction or the like may be caused when the photopolymerizable resin is formed. Therefore, the above half-life temperature can be appropriately controlled within a range of 30 ° C or higher.

When the half-life temperature of the thermal initiator exceeds 70 ° C, when a polar monomer is polymerized, a side reaction based on a double bond may continue to occur, and a side reaction that continues to occur may cause a gel reaction, which may make it difficult to form a single reaction. The polymerization of the body. Therefore, the half-life temperature of the thermal initiator is set to 70 ° C or less, the low heat of reaction is maintained, and the thermal initiator is consumed at a relatively low temperature, and the initiation is relatively fast, and can be performed in a relatively short period of time. A polymer photopolymerizable resin is formed.

Further, the thermal initiator is characterized in that it can absorb ultraviolet rays. Absorbing ultraviolet light The thermal initiator of the wire is different from the general thermal initiator which forms a radical by heat, and can form a radical by ultraviolet absorption. The thermal initiator capable of absorbing ultraviolet light can absorb ultraviolet rays in the wavelength range of 300 to 400 nm which is mainly used under photopolymerization conditions under mild conditions, and therefore can be utilized under mild conditions as compared with general thermal initiators. Photopolymerization. Therefore, even if the 10-hour half-life temperature of the general thermal initiator is maintained at 70 ° C or lower, if the ultraviolet initiator capable of absorbing ultraviolet rays having the above half-life temperature is used for polymerization by photopolymerization, the polymerization conditions can be varied. Since the heat of reaction is low, it is advantageous in that polymerization can be carried out under mild conditions.

Specifically, the thermal initiator is generally an azo compound or a peroxy compound, but the present invention is characterized in that the thermal initiator is an azo compound having a half life temperature in the above range. Peroxy compounds include benzoyl peroxide, dilaurin peroxide, Di-tetra-butyl peroxide, cumyl hydroxyperoxide, etc., but they The half-life temperature exceeds 70 °C. In contrast, azo compounds have a relatively low half-life temperature and are therefore preferred.

The azo compound can be selected from 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethyl). (2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (2,2'- Azobis(4-methoxy-2,4-dimethylvaleronitrile), Dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis[2-( 2-imidazolin-2-yl)propane dihydrochloride (2,2'-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride) and 2,2'-azobis[N- At least one of the group consisting of (2,2'-azobis[N-(2-carboxyethyl)-2-methyl-propionamidine]hydrate) . A thermal initiator having a 10-hour half-life temperature of 70 ° C or less can be formed using at least one selected from the group consisting of the azo compounds, and the above effects can be brought about by limiting the half life.

The photopolymerizable resin composition of the present invention is characterized in that it contains 3 to 30 parts by weight of the crosslinkable functional group-containing monomer and 0.003 to 1 by weight based on 100 parts by weight of the (meth) acrylate monomer. Parts of the thermal initiator.

Preferably, in the copolymer, relative to 100 parts by weight of the (meth) propylene The acid ester monomer contains 3 to 30 parts by weight of the crosslinkable functional group-containing monomer. If the content is less than 3 parts by weight, the initial adhesive strength and the peel strength of the adhesive may decrease, and if the above content is greater than 30 parts by weight, when the photopolymerizable resin composition is polymerized, there is a fear that a gel reaction is easily generated.

Further, preferably, the thermal initiator is contained in an amount of 0.003 to 1 part by weight based on 100 parts by weight of the (meth) acrylate monomer, and if the content is less than 0.003, there is a problem in initiating a reaction, and if When the content is more than 1 part by weight, there is a concern that a polymer having a low molecular weight will be polymerized.

Preferably, the photopolymerizable resin composition further contains 0.002 to 1 part by weight of a molecular weight regulator (Chain Transfer Agent, hereinafter abbreviated as "100 parts by weight" based on 100 parts by weight of the (meth) acrylate monomer. CTA"), when the CTA is less than 0.002 parts by weight, it is difficult to control the reaction temperature and the reaction rate, and when the CTA is more than 1 part by weight, the molecular weight may become small.

At this time, the above molecular weight modifier is also referred to as a chain transfer agent, and the molecular weight of the photopolymerizable resin to be formed can be adjusted depending on the content. In radical polymerization for forming a photopolymerizable resin from a photopolymerizable resin composition, an active site which causes an addition reaction is referred to as a radical chain. At this time, the CTA reacts more easily than the radical chain and the conventional monomer for addition, thereby stopping the growth of the free radical chain during growth, making the CTA have an active point, and finally exerting an activity to transfer to other monomers. Since the point acts, it is possible to adjust the reaction rate by adding CTA during radical polymerization.

However, in the case where too much CTA is used, the reaction is difficult to proceed, and the molecular weight of the produced photopolymerization resin is lowered. Therefore, in the case of the present invention, a thermal initiator having a half-life temperature is limited to adjust the reaction. The speed, so that even if less CTA is used, the molecular weight of the resulting photopolymerizable resin can be increased.

This CTA mainly uses a mercapto group (-SH) as a functional group because the ~SH binding energy is lower than that of other sigma, and therefore, it can be easily changed into a radical. More specifically, the CTA may comprise 2-mercaptoacetate, N-dodecyl mercaptan or 4-4'-thiobisphenylthiophenol (4-4'). -thiobis benzenethiol), and 2-mercaptoacetate, n-dodecyl mercaptan (n-dodecylmercaptan) is preferred because it has a long carbon number and does not have a strong pungent odor. The 4-4'-thiobisbenthiol (4-4'-thiobisbenzenthiol) has a different effect on the molecular weight or the degree of polymerization, and thus has a greater influence on physical properties. less.

Photopolymerized resin

The present invention provides a photopolymerizable resin obtained by polymerizing a (meth) acrylate monomer, a crosslinkable functional group-containing monomer, and a thermal initiator capable of absorbing a half-life of 10 hours and having a temperature of 70 ° C or less.

By the polymerization of the photopolymerizable resin composition, a photopolymerizable resin such as an acrylic resin can be prepared. Therefore, in the initiation of the polymerization reaction, a thermal initiator capable of absorbing ultraviolet rays having a half-life temperature limitation can be used to enable the reaction. Keep it slow and have a faster reaction rate.

The photopolymerizable resin composition of the present invention contains a thermal initiator capable of absorbing ultraviolet rays, and the polymerization method can be carried out by irradiating an active energy ray such as an ultraviolet ray or an electron beam which activates a thermal initiator capable of absorbing ultraviolet rays.

When the ultraviolet irradiation method is applied, for example, ultraviolet rays can be irradiated by a high pressure mercury lamp, a metal halide lamp, a black light lamp or the like. In the ultraviolet curing method, the irradiation amount is not particularly limited as long as it does not deteriorate the physical properties of the photopolymerizable resin composition and is controlled to be sufficiently cured. For example, preferably, the illuminance is 50 to 1000 mW. /cm ² , the amount of light is 50~1000mJ/cm ² .

Specifically, when the photopolymerizable resin composition is polymerized, when ultraviolet rays are irradiated with a light amount of less than 50 mJ/cm ² , the amount of irradiation required for initiation of the thermal initiator is insufficient, and there is a fear that polymerization cannot be formed, and is larger than When the amount of light of 1000 mJ/cm ² is irradiated with ultraviolet rays, the rate of polymerization is too fast, and there is a problem that it is difficult to control the reaction rate. Therefore, by maintaining the amount of ultraviolet irradiation of the above-described amount of light, the reaction can be initiated and the effect of adjusting the reaction rate can be excellent. More specifically, the reaction rate is fixed at 30 ° C, and ultraviolet rays are irradiated with a light amount of 50 to 1000 mJ/cm ² to carry out polymerization, which makes the heat generation temperature at the time of polymerization lower.

The present invention is characterized in that the photopolymerizable resin composition is polymerized to form a light polymerization When the resin composition is combined, the heat generation temperature is 30 to 40 °C. When the polymerization is carried out, a relatively low heat generation temperature is maintained, and a side reaction of a UV polar monomer having a double bond and an additional gel reaction do not occur, whereby the reaction can be adjusted when the photopolymerization resin is polymerized. Heat and reaction rate.

When a (meth) acrylate monomer, a crosslinkable functional group-containing monomer, and a thermal initiator undergo a continuous polymerization reaction, heat generation occurs, and by referring to the heat generation temperature, the reaction rate of the polymerization reaction can be predicted. reaction speed. When the monomer and the thermal initiator are polymerized into a photopolymerization resin, if the heat generation temperature is less than 30 ° C, there is a problem that the polymer having a target molecular weight set to be aggregated cannot be aggregated, and if the heat generation temperature is higher than 40 ° C, UV is caused. In the reaction between polar monomers, there is a problem that a gel reaction or a side reaction occurs.

The above photopolymerizable resin prepared by polymerization may have a molecular weight of up to 1,000,000 or more. In the past, when UV curing was carried out, a large amount of heat of reaction was generated due to the reactivity of the monomer and the photoinitiator, and therefore, it was not easy to adjust the molecular weight. Further, in order to adjust the initiation of radicals, the molecular weight of the photopolymerizable resin produced by using a large amount of CTA is about 500,000 to 600,000. However, in the case of the present invention, when a photopolymer resin composition containing a thermal initiator having a half life limit is polymerized into a photopolymerizable resin, a low heat of reaction can be maintained even if the amount of CTA to be added is minimized. It can also increase the molecular weight.

Therefore, specifically, the molecular weight of the photopolymerizable resin may be set to 1.2 million or more, more specifically 1.4 million or more, and when the molecular weight of the photopolymerizable resin is less than 1,000,000, the peeling strength and durability of the adhesive are weak. The problem.

Examples and comparative examples

Examples of the present invention are described in Table 1 below. More specifically, 2-ethylhexyl (meta)acrylate is used as the (meth) acrylate monomer, and 2-hydroxyethyl (meth) acrylate is contained. a hydroxy monomer, and (meth)acrylic acid as a carboxyl group-containing monomer, and a thermal initiator containing ultraviolet rays (Example 1, Example 2, Comparative Example 3, Comparative Example 4) was prepared, and ultraviolet rays could not be absorbed. A photopolymerizable resin composition of a thermal initiator (Comparative Example 5, Comparative Example 6) or a photoinitiator (Comparative Example 1 and Comparative Example 2). At this time, the content of the photoinitiator, thermal initiator or CTA is a part by weight relative to 100 parts by weight of the (meth) acrylate monomer.

Experimental Example - Characteristics of Photopolymerized Resin

In order to photopolymerize the photopolymerizable resin composition of the above Table 1, after irradiating a black fluorescent lamp for about 5 minutes, the maximum heat generation temperature at the time of the reaction progress was measured. Thereafter, the molecular weight of the polymerized photopolymerized resin was measured by a 1260 Infinity Gel Permeation Chromatogtaphy (GPC) system (Agilent Technologies, USA).

Table 2 above shows the measurement results of the heat generation temperature and the molecular weight at the time of polymerization in the above examples and comparative examples. Referring to the above Table 2, in the case of Example 1 and Example 2, the polymerization of the photopolymerizable resin composition containing a thermal initiator having a half-life temperature of 70 ° C or less is formed to form a photopolymerizable resin having a molecular weight of 1,000,000 or more. Moreover, the heat generation temperature at the time of polymerization also maintained at a low level of 40 ° C or lower. Specifically, at the time of polymerization, the reaction was initiated by ultraviolet rays, and the temperature of the reaction heat was maintained at 30 °C.

On the other hand, in the case of Comparative Example 1 and Comparative Example 2 containing a photoinitiator instead of a thermal initiator, when the photopolymerization resin was polymerized, the heat generation temperature was high, and it was difficult to adjust the reaction, and only stayed at the time. A photopolymerizable resin having a lower molecular weight is prepared. Further, in the case of Comparative Example 3 and Comparative Example 4, the reaction temperature was set to 30 ° C, and the polymerization reaction was initiated by ultraviolet absorption. However, the high thermal initiator having a half-life temperature of 70 ° C or higher could not be maintained. Lower heating temperature below 40 ° C, therefore, there are difficulties in polymerization, only obtained A photopolymerizable resin having a molecular weight of about 500,000.

In the case of Comparative Example 5 and Comparative Example 6, although a thermal initiator having a half-life temperature of 70 ° C or lower was used, since the reaction temperature was fixed at 70 ° C and the reaction was initiated by heat, instead of being induced by ultraviolet absorption, The measured heat generation temperature was about 100 ° C or higher, and a high heat generation reaction occurred. As a result, the polymerization reaction between the monomers was impossible due to the progress of the gel reaction, and the molecular weight could not be measured. On the contrary, as described above, the heat generation temperature measured in Examples 1 and 2 which have a decay temperature of 70 ° C or less and which can absorb the ultraviolet heat initiator is 40 ° C or less, and is carried out without a gel reaction. Polymerization between the bodies.

Further, in the case of Example 1 and Example 2, compared with Comparative Example 1 to Comparative Example 4, although a small amount of CTA was contained, since the reaction heat was low, the polymerization became high in the absence of other side reactions. A molecular weight photopolymerizable resin. Therefore, the photopolymerizable resin composition of the present invention containing a thermal initiator capable of absorbing ultraviolet rays having a half-life limit can adjust the heat of reaction and the reaction rate even when a small amount of CTA is used in forming a photopolymerizable resin. With a low heat generation temperature, a photopolymerizable resin having a large molecular weight can be prepared by a controlled reaction rate.

While the invention has been described above in terms of the preferred embodiments, the invention is not intended to limit the invention, and the invention may be practiced without departing from the spirit and scope of the invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims.

Claims (12)

A photopolymerizable resin composition comprising: a (meth) acrylate monomer; a monomer having a crosslinkable functional group; and a thermal initiator capable of absorbing ultraviolet rays having a half hour life of 10 hours and having a temperature of 70 ° C or less . The photopolymerizable resin composition according to claim 1, wherein the (meth) acrylate monomer is selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, (methyl) N-propyl acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-tert-butyl (meth)acrylate, amyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl methacrylate, isodecyl ester, lauryl methacrylate and At least one of the group consisting of tetradecyl (meth)acrylate. The photopolymerizable resin composition according to claim 1, wherein the crosslinkable functional group-containing monomer is at least selected from the group consisting of a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and a nitrogen-containing monomer. One. The photopolymerizable resin composition according to claim 1, wherein the thermal initiator is an azo compound. The photopolymerizable resin composition according to claim 4, wherein the azo compound is selected from the group consisting of 2,2'-azobis(isobutyronitrile) and 2,2'-azobis (2,4). - dimethyl valeronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl azobisisobutyrate, 2,2'-couple Nitrogen bis[2-(2-imidazolin-2- At least one of the group consisting of propane]dihydrochloride and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine hydrate. The photopolymerizable resin composition according to claim 1, wherein the photopolymerizable resin composition contains 3 to 30 parts by weight based on 100 parts by weight of the (meth) acrylate monomer. A monomer having a crosslinkable functional group and 0.003 to 1 part by weight of the thermal initiator. The photopolymerizable resin composition according to claim 1, wherein the photopolymerizable resin composition further comprises 0.002 to 1 part by weight based on 100 parts by weight of the (meth) acrylate monomer. Molecular weight regulator. The photopolymerizable resin composition according to claim 7, wherein the molecular weight modifier is selected from the group consisting of 2-mercaptoacetate, n-dodecyl mercaptan and 4-4'-thiobisphenylthiophenol. At least one of the group consisting of. A photopolymerizable resin obtained by polymerizing a photopolymerizable resin composition as described in claim 1 of the patent application. The photopolymerizable resin according to claim 9, wherein when the polymerization is carried out, ultraviolet rays having a light amount of 50 to 1000 mJ/cm ^{2 are} irradiated. The photopolymerizable resin according to claim 9, wherein the heat generation temperature at the time of the polymerization is from 30 ° C to 40 ° C. The photopolymerizable resin according to claim 9, wherein the photopolymerization resin has a molecular weight of 1,000,000 or more.