JP6753038B2 - Photocurable composition - Google Patents

Description

The present invention relates to a photocurable composition, in particular, a photocurable composition for photo-nanoimprinting on a resin surface of a resin substrate, which is not colored and has excellent adhesiveness and flexibility. It relates to a sex composition.

Conventionally, photolithography technology has been used to impart a fine texture to the surface of a resin substrate, but with the advancement of nanoimprint technology, a mold having an inverted pattern of the texture shape to be formed is placed on the substrate to be transferred. By embossing the formed resin film layer, it has become possible to form a texture at low cost and with good productivity. Such nanoimprint technology is roughly classified into two types according to the resin film layer to be transferred.

The texture in the present invention is a fine uneven pattern, which may be either a periodic structure or a non-periodic structure, and the size of the unevenness is 100 nm to 100 μm.

Of the two types, one is a thermal nanoimprinting technique in which the transferred resin film layer is heated, plastically deformed by a mold, and then the mold is peeled off to form a texture, and the other is a thermal nanoimprint technique on a substrate at room temperature. After applying the liquid active energy ray-curable composition, a light-transmitting mold is applied, and the active energy ray is irradiated through the mold or a transparent resin substrate to cure the active energy ray on the resin substrate. This is an optical nanoimprint technology that cures a sexual composition and peels off a mold to form a texture. In particular, the optical nanoimprint technology can form a texture at room temperature, so deformation of the resin substrate due to heat and distortion due to the difference in linear expansion coefficient between the mold and the resin substrate are unlikely to occur, enabling highly accurate patterning. ..

Therefore, as a photocurable composition used in the optical nanoimprint technology, for example, Patent Document 1 proposes a photocurable composition having low volatility and low viscosity. Further, Patent Document 2 proposes a curable adhesive composition containing an ethylenically unsaturated group-containing compound and having a glass transition temperature of a cured product of 60 ° C. or higher and a water absorption rate of 10% or lower. Further, Patent Document 3 proposes a photocurable adhesive having excellent adhesiveness under high temperature and high humidity. Patent Document 4 proposes an active energy ray-curable adhesive composition for hydrophilic plastics. Further, Patent Document 5 proposes a photocurable adhesive using an aliphatic (meth) acrylate-based oligomer and an aliphatic acrylate-based monomer.

Japanese Unexamined Patent Publication No. 2010-159369 Japanese Unexamined Patent Publication No. 2013-112693 Japanese Unexamined Patent Publication No. 7-292323 Japanese Patent No. 5633511 Japanese Unexamined Patent Publication No. 2012-72328

However, the disclosed technique of Patent Document 1 is inferior in adhesiveness to the surface of the resin substrate. Further, in the technique disclosed in Patent Document 2, the viscosity is high and the fluidity is lowered, and a long time and high pressurization are required until the mold formed of the mold and the substrate is filled. Further, if the viscosity is low, the curing shrinkage becomes relatively large, and the shape of the mold and the shape of the resin after transfer are different, which is not preferable. Further, the technique disclosed in Patent Document 3 has sufficient performance for use as an adhesive, but when used as a material for optical nanoimprint, it cannot be removed from the mold due to its strong adhesion to the mold. Since it is hard and brittle, there is a problem that it breaks inside the resin during curing and fills the texture of the mold. Once the texture of the mold is filled, it becomes difficult to reuse the mold. Moreover, since the cured resin is hard and brittle, it is also inferior in flexibility.

Further, in Patent Document 4, although it adheres well to a hydrophilic film, there are restrictions on the substrate, and in particular, it does not adhere to a photocurable resin having excellent solvent resistance and a surface hardness of 3H or more. , Or it is difficult to adhere. Further, Patent Document 5 proposes a photocurable adhesive using an aliphatic (meth) acrylate-based oligomer and an aliphatic acrylate-based monomer, but this material has a very low elastic modulus and is textured at a high temperature. It is unsuitable because the shape of the shape cannot be maintained.

Therefore, under such a background, the present invention provides a photocurable composition which is not colored when, for example, optical nanoimprinting is performed on the surface of a resin substrate, and has excellent adhesiveness to the resin surface and further flexibility. The purpose is to do.

However, as a result of diligent research in view of such circumstances, the present inventors, etc., in the photocurable composition, the viscosity of the composition, the contact angle with respect to the resin surface, the curing shrinkage rate at the time of curing, and the glass of the cured resin. By optimizing the transition temperature, we found that there was no coloring and that it was excellent in adhesiveness and flexibility, and completed the present invention.

That is, the gist of the present invention is a photocurable composition containing the following components (A) to (C), the composition having a viscosity at 23 ° C. of 50 to 300 mPa · s. The contact angle with respect to the polymethylmethacrylate base material is 25 degrees or less, the curing shrinkage rate when the composition is cured is 6 to 9%, and the glass transition temperature when the composition is cured is 80 to 150 ° C. It relates to a photocurable composition characterized by being present.
Component (A): Compound having one ethylenically unsaturated group selected from vinyl group, (meth) acryloyl group and (meth) acrylamide group Component (B): Contains alicyclic diisocyanate, aromatic polycarbonate diol and hydroxyl group Urethane (meth) acrylate component (C): a photopolymerization initiator that is formed by reacting (meth) acrylate and has two or more ethylenically unsaturated groups.

The photocurable composition of the present invention is not colored and has excellent properties such as adhesiveness to a resin substrate, peelability from a mold, flexibility, optical and thermal properties, and mechanical properties even as an optical nanoimprint material. It is particularly suitable for materials for optical nanoimprint.

The present invention will be described in detail below.
In the present invention, "(meth) acrylate" is a general term for acrylate and methacrylate.
Further, in the present invention, "nano" in the expression of optical nanoimprint includes a size of about 100 nm to 100,000 nm.

The photocurable composition of the present invention has a viscosity of the composition at 23 ° C. of 50 to 300 mPa · s, a contact angle of the composition with respect to a polymethylmethacrylate base material of 25 degrees or less, and the composition is cured. The curing shrinkage rate is 6 to 9%, and the glass transition temperature when the composition is cured is 40 to 150 ° C.

The above viscosity is 50 to 300 mPa · s, preferably 70 to 200 mPa · s, particularly preferably 80 to 100 mPa · s from the viewpoint of fluidity to the mold, and the curing shrinkage is compared when the viscosity is low. The target becomes large and a difference occurs between the shape of the mold and the shape after transfer. If the value is high, the fluidity of the mold to the texture pattern decreases, and a long time or high pressurization is required before the mold is filled.

The above contact angle is preferably 25 degrees or less, preferably 5 to 20 degrees in terms of adhesiveness to the resin substrate after curing, and if the contact angle is large, the adhesiveness to the resin substrate is lowered. Will be done. On the contrary, if it is extremely small, it becomes difficult to peel off the fine texture from the mold. The contact angle can be controlled by the type and amount of the components.

The curing shrinkage rate is 6 to 9%, preferably 6.5 to 8.5%, and particularly preferably 7 to 8% in terms of mold transfer accuracy. If the shrinkage rate is low, the phenomenon of sticking to the mold and being difficult to peel off occurs, and if it is high, the texture shape of the mold and the texture shape of the resin after transfer will be different.

In the present invention, the photocurable composition has a glass transition temperature of 80 to 150 ° C., preferably 80 to 140 ° C., from the viewpoint of adhesiveness to a substrate and mold transferability. It is particularly preferably 80 to 130 ° C. If the glass transition temperature is too low, the resin will adhere to the fine irregularities when peeling from the mold, making it difficult to peel, and the transfer shape accuracy will tend to decrease. If it is too high, the resin will be fine when peeling. The unevenness tends to be chipped.

That is, it is preferable that the photocurable composition of the present invention is photocured to form a cured resin, and the glass transition temperature of the cured resin is in the above range.
The adjustment of the glass transition temperature is obtained by adjusting the composition and ratio of the photocurable composition.

In the present invention, the photocurable composition satisfying the above physical properties can be obtained by containing the following components (A) to (C).
Component (A): Compound having one ethylenically unsaturated group selected from vinyl group, (meth) acryloyl group and (meth) acrylamide group Component (B): Contains alicyclic diisocyanate, aromatic polycarbonate diol and hydroxyl group Urethane (meth) acrylate component (C): a photopolymerization initiator that is formed by reacting (meth) acrylate and has two or more ethylenically unsaturated groups.

The component (A) is a compound having one ethylenically unsaturated group, as the ethylenically unsaturated group, a bicycloalkyl group, (meth) acryloyl group, include (meth) acrylamide group. Of these, the (meth) acryloyl group is preferably used. One type of component (A) may be used, or a plurality of components (A) may be used at the same time.

Examples of the compound having a vinyl group include styrene, vinyltoluene, N-vinylformamide, N-vinylpyrrolidone, N-vinylcaprolactam and the like.

Examples of the compound having a (meth) acryloyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, and stearyl. (Meta) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, methacryloyloxymethyltetracyclodecane, methacryloyloxymethyltetracyclododecene, isobonyl (meth) acrylate, adamantyl (meth) acrylate, 2-methoxy Ethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, 2-ethylhexylcarbitol (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, N- (meth) Examples thereof include acryloyloxyethyl tetrahydrophthalimide, tetrahydrofurfuryl (meth) acrylate, and (meth) acryloylmorpholin. Of these, (meth) acryloyl morpholine is preferable in terms of viscosity and contact angle with the resin substrate.

Examples of the compound having a (meth) acrylamide group include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide and the like.

The component (B) is a urethane (meth) acrylate having two or more ethylenically unsaturated groups, and is usually formed by reacting a diisocyanate with a diol and a hydroxyl group-containing (meth) acrylate.

The present invention is characterized in that it is a urethane (meth) acrylate obtained by reacting an alicyclic diisocyanate with an aromatic polycarbonate diol and a hydroxyl group-containing (meth) acrylate in terms of adhesion to a substrate and mold transferability. To do .

Examples of the alicyclic diisocyanate include isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, hydrogenated xylylene diisocyanate, and hydrogenated. Examples thereof include diphenylmethane diisocyanate and trimeric compounds of these diisocyanates. Of these, isophorone diisocyanate is preferable in terms of mold transferability.

Examples of the aromatic polycarbonate diol include a reaction product of a polyhydric alcohol and phosgene; a ring-opening polymer of a cyclic carbonate (alkylene carbonate, etc.). Among them, bisphenol A is preferable as the polyhydric alcohol in terms of adhesiveness to the substrate.

Further, it is preferable that the number of repetitions of the carbonate structural unit in the aromatic polycarbonate diol is 10 to 20 in terms of adhesiveness to the resin substrate and mold transferability, particularly preferably 12 to 18, and even more preferably 13 to 16. Is. If the number of repetitions is too small, the adhesiveness tends to decrease, and if it is too large, the viscosity tends to increase.

Examples of the hydroxyl group-containing (meth) acrylate include monofunctional (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate; 2-hydroxy. -3- (Meta) Acryloyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tri (meth) acrylate and other polyfunctional (meth) acrylates Can be mentioned. Among them, monofunctional (meth) acrylate is preferable in terms of curing shrinkage rate, and 2-hydrochiethyl (meth) acrylate is particularly preferable.

Further, when the urethane (meth) acrylate (B) is produced by reacting the above-mentioned diisocyanate, diol and hydroxyl group-containing (meth) acrylate, it is preferable to use a catalyst such as dibutyltin dilaurate, if necessary.

Thus, the component (B) is obtained by reacting the above-mentioned diisocyanate, diol and hydroxyl group-containing (meth) acrylate. Among these, acrylate is preferable from the viewpoint of curing rate, and bifunctional is preferable from the viewpoint of flexibility.

The urethane (meth) acrylate of the component (B) may be used by mixing two or more kinds. Further, if necessary, a polyfunctional urethane (meth) acrylate different from the above may be further mixed.

The weight average molecular weight of the urethane (meth) acrylate of the component (B) is preferably 1000 to 20000, particularly preferably 2000 to 15000, and further preferably 3000 to 10000. If the weight average molecular weight is too small, the cured resin itself tends to be brittle, and if it is too large, the viscosity of the photocurable composition tends to be high, making molding difficult.

The above component (C) is a photopolymerization initiator, for example, benzophenone, benzoin methyl ether, benzoin propyl ether, diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,4. , 6-trimethylbenzoyldiphenylphosphine oxide and the like. Among these, radical cleavage type photopolymerization initiators such as 1-hydroxycyclohexylphenyl ketone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are preferable. These photopolymerization initiators (C) may be used alone or in combination of two or more.

In the present invention, the above-mentioned component (A), component (B) and component (C) are contained, but the content of each component is 100 in total of the component (A) and the component (B). With respect to parts by weight, the content of the component (A) is 50 to 80 parts by weight, the content of the component (B) is 20 to 50 parts by weight, and the content of the component (C) is 0.01 to 10 parts by weight. It is preferable to have.

The preferable content of the component (A) is 55 to 70 parts by weight, particularly preferably 60 to 70 parts by weight, and the preferable content of the component (B) is 30 to 45 parts by weight, particularly preferably 30 to 70 parts by weight. It is 40 parts by weight. If the content of the component (A) is too low and the content of the component (B) is too high, the viscosity tends to increase, and at a high viscosity, the fluidity of the composition to the fine texture of nanoimprint tends to decrease. If the content of the component (A) is too large and the content of the component (B) is too small, the flexibility of the cured resin tends to decrease and the adhesiveness tends to decrease.

The preferable content of the component (C) is 0.05 to 5 parts by weight, particularly preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the total of the component (A) and the component (B). .. If the content of the component (C) is too small, the polymerization rate is lowered, and the polymerization tends to be difficult to proceed sufficiently, and if it is too large, it tends to cause coloring.

In the present invention, a small amount of auxiliary components may be contained as long as the object of the present invention is not impaired. For example, a monomer having an ethylenically unsaturated group other than the components (A) and (B), a polymerization inhibitor, a thermal polymerization initiator, a chain transfer agent, an antioxidant, an ultraviolet absorber, an antifoaming agent, and a level. Ring agents, brewing agents, dye pigments, fillers, etc.

Examples of the monomer having an ethylenically unsaturated bond other than the components (A) and (B) include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and tetra. Di (meth) acrylate of polyethylene glycol above ethylene glycol, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2-hydroxy1 , 3-Di (meth) acryloxypropane, 2,2-bis [4- (meth) acryloyloxyphenyl] propane, bis (hydroxy) tricyclo [5.2.1.0 ^2,6 ] decane-di (meth) ) Acrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = di (meth) acrylate, bis (hydroxy) tricyclo [5.2.1.0 ^2,6 ] decane = acrylate methacrylate , Bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] Decane = acrylate methacrylate, Bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] Pentadecane = di (meth) acrylate, bis (hydroxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] Pentadecane = di (meth) acrylate, bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] Pentadecane = acrylate methacrylate, bis (hydroxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] Pentadecane = acrylate methacrylate, 2,2-bis [4- (β-methacryloyloxyethoxy) cyclohexyl] propane, 1,3-bis (methacryloyloxymethyl) cyclohexane, 1,3-bis (methacryloyloxyethyl) Bifunctional (meth) acrylates such as oxymethyl) cyclohexane, 1,4-bis (methacryloyloxymethyl) cyclohexane, 1,4-bis (methacryloyloxyethyloxymethyl) cyclohexane; trimethylpropantri (meth) acrylate, 1, Examples thereof include trifunctional or higher functional (meth) acrylates such as 3,5-tris (methacryloyloxymethyl) cyclohexane and 1,3,5-tris (methacryloyloxyethyloxymethyl) cyclohexane.

The content of the monomer having an ethylenically unsaturated bond other than the components (A) and (B) is 30 parts by weight or less, moreover, with respect to 100 parts by weight of the total of the component (A) and the component (B). It is preferably 20 parts by weight or less, particularly preferably 10 parts by weight or less. If the content is too large, the viscosity and the contact angle with the substrate tend to be inconvenient.

A known compound can be used as the thermal polymerization initiator. For example, hydroperoxides such as hydroperoxide, t-butylhydroperoxide, diisopropylbenzenehydroperoxide, 1,1,3,3-tetramethylbutylhydroperoxide, di-t-butyl peroxide, dicumyl peroxide, etc. Dialkyl peroxides such as, t-butyl peroxybenzoate, peroxy esters such as t-butyl peroxy (2-ethylhexanoate), diacyl peroxides such as benzoyl peroxide, peroxy carbonates such as diisopropyl peroxy carbonate. , Peroxyketal, ketone peroxide and other peroxides.

As the chain transfer agent, a polyfunctional mercaptan compound is preferable. Examples of the polyfunctional mercaptan compound include pentaerythritol tetrakisthioglycolate and pentaerythritol tetrakisthiopropionate. These polyfunctional mercaptan compounds are preferably used in a ratio of usually 10 parts by weight or less with respect to 100 parts by weight of the photocurable composition, and more preferably 5 parts by weight or less, particularly 3 parts by weight or less. preferable. If the amount used is too large, the storage stability of the composition tends to decrease.

Examples of the antioxidant include 2,6-di-t-butylphenol, 2,6-di-t-butyl-p-cresol, 2,4,6-tri-t-butylphenol, and 2,6-di-. t-Butyl-4-s-butylphenol, 2,6-di-t-butyl-4-hydroxymethylphenol, n-octadecyl-β- (4'-hydroxy-3', 5'-di-t-
Butylphenyl) propionate, 2,6-di-t-butyl-4- (N, N-dimethylaminomethyl) phenol, 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 2 , 4-Bis (n-octylthio) -6- (4-hydroxy-3', 5'-di-t-butylanilino) -1,3,5-triazine, 4,4-
Methylene-bis (2,6-di-t-butylphenol), 1,6-hexanediol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], bis (3,5- Di-t-butyl-4-hydroxybenzyl) sulfide, 4,4'-di-
Thiobis (2,6-di-t-butylphenol), 4,4'-tri-thiobis (2,6)
-Di-t-butylphenol), 2,2-thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], N, N'-hexamethylenebis- (3,5) -Di-t-Butyl-4-hydroxyhydroxyhydrocinnamide, N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl]
Hydrazine, calcium (3,5-di-t-butyl-4-hydroxybenzyl) monoethylphosphonate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl) -4-Hydroxybenzyl) benzene, tris (3,5-di t-butyl-4-hydroxyphenyl) isocyanurate, tris (3,5-di t-butyl-4-hydroxybenzyl) isocyanurate, 1,3 5-Tris-2 [3 (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl isocyanate, tetrakis [methylene-3- (3', 5'-di-t-butyl-4-) Hydroxyphenyl) propionate] Compounds such as methane and 3,5-di-t-butyl-4-hydroxybenzylphosphite-diethyl ester can be mentioned, and these compounds may be used alone or in combination of two or more. Among these, tetrakis [methylene-3- (3', 5'-di-t-butyl-4-hydroxyphenyl) propionate] methane is particularly preferable because it has a large effect of suppressing hue.

The content of the antioxidant is usually preferably 0.001 to 1 part by weight, particularly preferably 0.01 to 0.5 part by weight, based on 100 parts by weight of the photocurable composition. If the amount of the antioxidant is too small, the light resistance and heat resistance tend to decrease, and if the amount is too large, the light transmittance tends to decrease.

Thus, the photocurable composition of the present invention is obtained.
Next, the photocurable composition of the present invention is cured by light, for example, when it is applied to optical nanoimprint or the like.

As a curing method in the present invention, it is preferable that the photocurable composition is photocured using ultraviolet rays having a wavelength of 200 to 400 nm at an irradiation light amount of 0.1 to 100 J / cm ² or less. A more preferable range of the irradiation light amount is 1 to 50 J / cm ² , and more preferably 5 to 30 J / cm ² . If the amount of irradiation light is too large, the productivity tends to decrease, and if it is too small, the polymerization tends to be insufficient. The illuminance of ultraviolet rays is preferably 10 to 5000 mW / cm ² , particularly preferably 100 to 1000 mW / cm ² . If the illuminance is too low, the inside of the cured resin tends not to be sufficiently cured, and conversely, if the illuminance is too high, the polymerization tends to run away and the birefringence tends to increase.

The ultraviolet source may be any one usually used in photopolymerization, and examples thereof include metal halide lamps, high-pressure mercury lamps, electrodeless mercury lamps, and LED lamps. In order to prevent the polymerization from running out of control due to infrared rays generated from the light source, it is also possible to use a filter that blocks infrared rays, a mirror that does not reflect infrared rays, or the like for the lamp. The cured resin obtained in the present invention is preferably heat-treated for improving the degree of polymerization or releasing stress-strain, and is particularly preferably heat-treated at 100 ° C. or higher.

Further, in the present invention, in the cured resin obtained by photocuring, the relationship between the amount of change in the b ^* value and the thickness of the cured resin when heated in air at 150 ° C. for 1 hour is described by the following formula ( It is preferable that it satisfies 1), particularly preferably it satisfies the formula (2), and more preferably it satisfies the formula (3).

b ^* Value change / T ≦ 1 ・ ・ ・ (1)
b ^* Value change / T ≦ 0.8 ・ ・ ・ (2)
b ^* Value change / T ≦ 0.5 ・ ・ ・ (3)
T: Thickness of cured resin (mm)

Further, in the present invention, the cured resin photocured between the resin substrates has good adhesiveness to the resin substrate, and when measured by the bending adhesive strength test method of the JIS K6856 adhesive. The bending adhesive strength of the above is preferably 250 mN / mm ² or more. The upper limit is usually 1000 mN / mm ² . If the adhesive strength is too small, it may peel off from the transferred resin substrate. If it is too large, peeling from the resin substrate does not occur, but it tends to hinder peeling from the mold. Further, from the viewpoint of the flexibility of the cured resin, the bending adhesive strength is preferably within the above range.
Further, even when SiO _x is formed on the surface of the resin substrate by vapor deposition or sputtering, the adhesiveness is improved, and in the bending adhesive strength tested using a slide glass that simulates the SiO _x surface. Can also obtain high adhesive strength.

In the present invention, it is preferable to apply the above photocurable composition to optical nanoimprint, and examples of the resin substrate for optical nanoimprint include polymethyl (meth) acrylate resin, polyethylene terephthalate resin, and polycarbonate resin. However, a (meth) acrylic resin substrate is preferably used. As the (meth) acrylic resin, in addition to the thermoplastic polymethylmethacrylate resin, a cured resin obtained by polymerizing a (meth) acrylic monomer or oligomer with light or heat can also be used.

Further, a substrate in which a photocurable hard coat layer having a pencil hardness of 3H or more is coated on the surface of the above-mentioned thermoplastic resin substrate or a resin substrate in which a SiO _X film is formed by vapor deposition or sputtering can also be used. ..

Thus, the photocurable composition of the present invention can be obtained, and in particular, as a photocurable composition for optical nanoprinting on the resin surface of a resin substrate, there is no coloring, and adhesiveness, mold transferability, and flexibility are also obtained. It will be excellent and very useful.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.
In the example, "part" and "%" mean a weight standard.

(1) Viscosity (mPa · s)
The measurement was performed at 23 ° C. and a rotation speed of 60 rpm using a B-type viscometer "LV DV-E" manufactured by BROOKFIELD.

(2) Contact angle (degrees) with the resin substrate
Using polymethylmethacrylate resin (PMMA: Acrylic, manufactured by Mitsubishi Rayon) as a resin substrate and using "Automatic Contact Angle Meter CA-V150" manufactured by Kyowa Interface Science Co., Ltd., a 21-gauge syringe with a needle tip angle of 90 ° is used for light. The curable composition was put in, and the droplets produced from the injection needle were contacted with the resin substrate and dropped to measure, and the contact angle was calculated by the θ / 2 method. The measurement atmosphere is 23 ° C. and 65% RH.

(3) Curing shrinkage rate (%)
The density ρ ₀ of the photocurable composition before curing was calculated from the volume and weight of the composition measured at 23 ° C., and the density ρ ₁ of the cured resin after curing was determined in accordance with JIS K7112. Obtained by measuring in water. From these densities, the curing shrinkage rate was calculated from the following formula according to JIS K7147.
Curing shrinkage rate (%) = (ρ ₀ −ρ ₁ ) × 100 / ρ ₁

(4) Glass transition temperature (Tg) (° C)
The photocurable composition is poured into a molding mold in which two polished glass plates face each other and a silicon plate having a thickness of 0.7 mm is used as a spacer, and an illuminance of 200 mW / cm ² and a light intensity of 25 J / are used using a metal halide lamp. Ultraviolet rays were irradiated at cm ² . After being cured by irradiation, the resin obtained by demolding was heated in a vacuum oven at 200 ° C. for 2 hours to obtain a cured resin having a length of 140 mm, a width of 140 mm, and a thickness of 0.7 mm.
A test piece obtained by cutting the cured resin into a size of 20 mm in length × 5 mm in width is used as a test piece, and the temperature is raised at a frequency of 10 Hz using the tension mode of the dynamic viscoelastic device “DVE-V4 type FT Leospector” manufactured by Rheology. The measurement was performed at a speed of 3 ° C./min and a strain of 0.025%. The ratio (tan δ) of the imaginary part (loss elastic modulus) to the real part (storage elastic modulus) of the obtained complex elastic modulus was determined, and the maximum peak temperature of this tan δ was defined as the glass transition temperature (Tg) (° C.).

(5) Bending adhesive strength (N / mm)
As substrates, (1) polymethylmethacrylate resin (Acrylite manufactured by Mitsubishi Rayon) (width 25 mm, length 100 mm, thickness 1 mm), (2) crown glass slide glass (width 25 mm, length 100 mm, thickness 1 mm). ), (3) A photocurable resin substrate (width 25 mm, length 100 mm, thickness 1 mm) having a surface pencil hardness of 4H prepared as described below was used.

<Manufacturing a photocurable resin substrate with a surface pencil hardness of 4H>
53.34 g (0.24 mol) of isophorone diisocyanate, 55.73 g (0.48 mol) of 2-hydroxyethyl acrylate, polymerized in a four-port flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. 0.02 g of hydroquinone methyl ether as a banning agent, 0.02 g of dibutyltin dilaurate as a reaction catalyst, and 500 g of methyl ethyl ketone were charged and reacted at 60 ° C. for 3 hours, and the reaction was terminated when the residual isocyanate group became 0.3%. The solvent was distilled off to obtain an isophorone skeleton-containing bifunctional urethane acrylate.
10 parts of urethane acrylate, 90 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decan-diacrylate ("A-DCP" manufactured by Shin Nakamura Chemical Industry Co., Ltd.), 1-hydroxycyclohexylphenyl ketone (1-hydroxycyclohexylphenyl ketone) A part of BASF's "Irgacure 184") was stirred at 60 ° C. until uniform, and then a photocurable composition (α) was obtained.
The obtained photocurable composition (α) was injected into a gap between two glass plates having a thickness of 1 mm and facing each other with a spacer in between, and an illuminance of 200 mW / cm ² and a light intensity of 25 J were used using a metal halide lamp. Ultraviolet rays were irradiated at / cm ² . The cured resin obtained by demolding was heated in a vacuum oven at 180 ° C. for 2 hours to obtain a photocurable resin substrate.
In the photocurable composition described above, the photocurable composition for producing a resin substrate is referred to as "photocurable composition (α)".

<Preparation of test pieces for measuring bending adhesive strength>
0.01 g of the photocurable composition was dropped onto the substrates (1) to (3) having a width of 25 mm, a length of 100 mm and a thickness of 1 mm, and a bonding margin of 25 mm in width and 12.5 mm in length (overlapping). The ^second substrate (1) to (3) is superposed on the area of the portion (312.5 mm ² ), and ultraviolet rays are irradiated with an illuminance of 200 mW / cm ² and a light intensity of 4 J / cm ² using a metal halide lamp. A test piece was prepared.

<Measurement of bending adhesive strength (N / mm ² )>
Next, in accordance with JIS K6856, the bending adhesive strength was measured using the test piece for measuring the bending adhesive strength. The moving distance speed of the load portion was set to 10 mm per minute. The bending adhesive strength was calculated by the following formula.
Bending adhesive strength (N / mm ² ) = maximum load (N) / area of the overlapped part of the test piece (mm ² )

(6) Coloring evaluation [measurement of b ^* value]
The photocurable composition is poured into a molding mold in which two polished glass plates face each other and a silicon plate having a thickness of 0.7 mm is used as a spacer, and an illuminance of 200 mW / cm ² and a light intensity of 25 J / are used using a metal halide lamp. Ultraviolet rays were irradiated at cm ² . After curing by irradiation, the cured product obtained by demolding is heated in a vacuum oven at 200 ° C. for 2 hours to form a resin molded product (test piece) having a length of 50 mm, a width of 50 mm, and a thickness of 0.7 mm. Obtained.

Two obtained resin molded bodies (test pieces) were prepared, left in a hot air dryer at 150 ° C. for 1 hour, taken out, and then allowed to cool. Using a Spectrophotometer "SE6000" manufactured by Nippon Denshoku Kogyo Co., Ltd., The b ^* value before and after heating was measured in the permeation measurement mode, and the average value of the two sheets was calculated.
[Measurement of thickness (mm)]
It was measured using a micrometer.
[B ^* Value change]
The amount of change in the b ^* value was calculated by setting the b ^* value before heating as b ₀ and the b ^* value after heating at 150 ° C. for 1 hour as b ₁ .
Then, to calculate the value of "b ^* value of the change amount / T" from the thickness variation and the cured resin of the b ^* value.

<Examples 1 to 3 and Comparative Examples 1 to 3>
[Preparation of photocurable composition]
As shown in Table 1, each component was blended and stirred at 60 ° C. until uniform to obtain a photocurable composition.
Each performance and each physical property of the obtained photocurable composition was measured and evaluated as described above.
The evaluation results of Examples and Comparative Examples are also shown in Table 1.

Note) Each component is as follows, and the values in parentheses are the parts by weight.
(*): Not measured [Component (A)]
・ ACMO: Acryloyl morpholine (manufactured by KJ Chemicals)
DMAA: N-dimethylacrylamide (manufactured by KJ Chemicals)
-THFA: Tetrahydrofurfuryl acrylate (Osaka Organic Chemical Industry "Viscoat # 150")
-MOI: 2-methacryloyloxyethyl isocyanate ("Karenzu MOI" manufactured by Showa Denko KK)

[Component (B)]
B-1: Isophorone diisocyanate 29.9 g in a four-necked flask equipped with a polycarbonate urethane acrylate thermometer having a bifunctional alicyclic skeleton, a stirrer, a water-cooled condenser, and a nitrogen gas inlet obtained by the following method. (0.14 mol), 54.2 g of polycarbonate diol (hydroxyl value 139.5 mgKOH / g; molecular weight calculated from hydroxyl value 804; 0.07 mol), 0.02 g of dibutyltin dilaurate as a reaction catalyst were charged, and at 60 ° C. It was reacted. When the residual isocyanate group became 6.7% or less, 15.9 g (0.14 mol) of 2-hydroxyethyl acrylate and 0.04 g of methoxyphenol as a polymerization inhibitor were further charged and reacted at 60 ° C. to remain. The reaction was terminated when the isocyanate group content was 0.3% or less to obtain urethane (meth) acrylate (B-1) (number of functional groups: 2, weight average molecular weight: about 5000).

B-2: 192.0 g (0.86 mol) of isophorone diisocyanate in a flask equipped with a urethane acrylate thermometer having a hexafunctional alicyclic skeleton, a stirrer, a water-cooled condenser, and a nitrogen gas inlet obtained by the following method. ) And 808.0 g (1.73 mol) of pentaerythritol triacrylate [mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (hydroxyl value 120 mgKOH / g)], 0.01 g of hydroquinone methyl ether as a polymerization inhibitor, 0.01 g of dibutyltin dilaurate was charged as a reaction catalyst and reacted at 60 ° C. for 8 hours, and the reaction was terminated when the residual isocyanate group became 0.3% or less to obtain urethane (meth) acrylate (B-2). It was.

-UN9200A: "Art Resin" manufactured by Negami Kogyo Co., Ltd.

[Component (C)]
-I184: 1-Hydroxycyclohexylphenyl ketone (BASF's "Irgacure 184")

[Other]
-ADE-200: Polyethylene glycol diacrylate (NOF Corporation "Blemmer ADE-200" )
· A-TMPT: trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)
-DCP: Bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] Decane-dimethacrylate (manufactured by Shin Nakamura Chemical Industry Co., Ltd.)

From the above evaluation results, in Example 1, the adhesiveness to the polymethylmethacrylate resin, the slide glass, and the photocurable resin substrate having a pencil hardness of 4H was good. Further, also in Examples 2 and 3, the adhesiveness to the polymethylmethacrylate resin and the slide glass was good. Moreover, in all the examples, the coloring at the time of heating was small. On the other hand, in Comparative Example 1, it is presumed that the viscosity is high and the fluidity of the mold to the texture pattern is insufficient. Further, in Comparative Examples 2 and 3, the adhesiveness to the polymethylmethacrylate resin and the slide glass was insufficient.

The photocurable composition of the present invention has excellent adhesiveness and flexibility without coloring in the adhesion between the photocurable cured resin and the resin substrate. For example, the photocurable composition for optical nanoimprinting is performed. It is very useful as a composition.

Claims (5)

A photocurable composition containing the following components (A) to (C) having a viscosity of 50 to 300 mPa · s at 23 ° C. of the composition, and contact of the composition with a polymethylmethacrylate base material. The photocuring feature is that the angle is 25 degrees or less, the curing shrinkage rate when the composition is cured is 6 to 9%, and the glass transition temperature when the composition is cured is 80 to 150 ° C. Sex composition.
Component (A): Compound having one ethylenically unsaturated group selected from vinyl group, (meth) acryloyl group and (meth) acrylamide group Component (B): Contains alicyclic diisocyanate, aromatic polycarbonate diol and hydroxyl group Urethane (meth) acrylate component (C): a photopolymerization initiator that is formed by reacting (meth) acrylate and has two or more ethylenically unsaturated groups. In a cured resin obtained by curing a photocurable composition, the relationship between the amount of change in the b * value and the thickness of the cured resin when heated in air at 150 ° C. for 1 hour is the following formula (1). The photocurable composition according to claim 1, wherein the photocurable composition satisfies the above.
amount of change in b * value / T ≦ 1 ・ ・ ・ (1)
T: Thickness of cured resin (mm) The content of the component (A) is 50 to 80 parts by weight, the content of the component (B) is 20 to 50 parts by weight, and the component (C) is 100 parts by weight in total of the component (A) and the component (B). The photocurable composition according to claim 1 or 2, wherein the content of the photocurable composition is 0.01 to 10 parts by weight. The photocurable composition according to any one of claims 1 to 3 , wherein the number of repetitions of the carbonate structural unit in the aromatic polycarbonate diol is 10 to 20. The photocurable composition according to any one of claims 1 to 4 , wherein the weight average molecular weight of the component (B) is 1000 to 20000.