JP2020158650A - Curable composition and cured product of the same - Google Patents

Abstract

To provide a curable composition capable of forming a cured product which has excellent adhesiveness to a substrate and a high total light transmittance and is favorably suppressed in cloudiness and to provide a cured product of the same.SOLUTION: There are provided: a curable composition which comprises (A) a urethane (meth)acrylate, (B) a thiocarboxylic acid derivative, (C) a triallyl isocyanurate and (D) a photopolymerization initiator, wherein the curable composition comprises 50 pts.mass of (B) a thiocarboxylic acid derivative based on 100 pts.mass of (A) a urethane (meth)acrylate and 40 pts.mass of (C) a triallyl isocyanurate based on 100 pts.mass of (A) a urethane (meth)acrylate; and a cured product of the same.SELECTED DRAWING: Figure 3

Description

The present invention relates to curable compositions, such as curable compositions used in the manufacture of transparent displays and adhesives, and cured products thereof.

Due to recent advances in image formation technology, the improvement in image quality in electronic devices such as liquid crystal displays and touch panels is remarkable. In order to improve the reproducibility of such a high-quality image, it is desired to improve the quality of the screen of the image display device and the like. That is, in order for the image display device to be able to reproduce high-quality moving images and still images with high accuracy, it is essential that the display and its adhesive have excellent transparency, that is, they are colorless and transparent.

In order to obtain a cured resin having high transparency that meets such requirements, an active energy ray-curable resin composition using a photocurable component and predetermined inorganic particles has been proposed (Patent Document 1). .. In the same document, haze (cloudiness) is controlled as an index of transparency, whereby an excellent curable composition having high transparency is obtained.

Japanese Unexamined Patent Publication No. 2009-242681

The transparent cured product of the curable composition used in a screen or the like of an image display device has a demand for making an image brighter and clearer. However, in the conventional resin composition as shown in Patent Document 1, although the predetermined transparency is obtained, the light transmittance is not examined, and the clear visibility of the image is not always sufficient. Absent.
Further, in the manufacture of an electronic device, it is required that the curable composition adheres well to the main body of the electronic device (such as a substrate). Under such circumstances, there is still room for improvement in the conventional resin composition in terms of maintaining the quality under predetermined usage conditions and adhering to the substrate.

The present invention provides a curable composition capable of forming a cured product having excellent adhesion to a substrate, high total light transmittance and well-suppressed cloudiness, and a cured product thereof. The purpose.

As a result of diligent studies in view of the above, the present inventors have cured the mixture containing (A) urethane (meth) acrylate, (B) thiocarboxylic acid derivative, (C) triallyl isocyanurate, and (D) photopolymerization initiator. In the sex composition, 50 parts by mass or more of the (B) thiocarboxylic acid derivative with respect to 100 parts by mass of (A) urethane (meth) acrylate, and (C) with respect to 100 parts by mass of (A) urethane (meth) acrylate. We have found that the above-mentioned problems can be solved by a curable composition containing 40 parts by mass or more of triallyl isocyanurate, and have completed the present invention.

In the curable composition of the present invention, the total mass of (A) urethane (meth) acrylate, (B) thiocarboxylic acid derivative, and (C) triallyl isocyanurate is 95% or more of the total mass of the curable composition. It is preferable to have.

Further, the problem of the present invention is solved by a transparent cured product obtained from the curable composition of the present invention.

The curable composition of the present invention has high adhesion to a substrate. Further, by curing the curable composition of the present invention, it is possible to obtain a highly transparent cured product having a high degree of cloudiness and a high total light transmittance.

It is a schematic diagram which shows the plate | plate which includes the recess used for making the molded article of this invention. It is a schematic diagram which shows the state which filled the concave part of the plate body with the photocurable composition of this invention. It is a schematic diagram which shows the process of covering a base material on a plate, and irradiating ultraviolet rays from a light source located above it. It is a schematic diagram which shows the state which the base material and the molded product are separated from a plate.

The curable composition of the present invention is a curable composition containing (A) urethane (meth) acrylate, (B) thiocarboxylic acid derivative, (C) triallyl isocyanurate, and (D) photopolymerization initiator. For 100 parts by mass of (A) urethane (meth) acrylate, 40 parts by mass or more of (B) thiocarboxylic acid derivative, and (C) triallyl isocyanurate with 100 parts by mass of (A) urethane (meth) acrylate. It is characterized by containing 50 parts by mass or more.
The curable composition of the present invention has excellent adhesion to a substrate, and the cured product has a high light transmittance and the haze is suppressed, thereby providing excellent transparency and transparency. Have.

In the present invention, Haze is used as an index of transparency.
Haze is the degree of cloudiness, which indicates the degree of transparency of transparent materials such as glass, plastic, and liquid. It is a percentage of the value obtained by dividing the scattered light transmittance of the test piece by the total light transmittance. expressed. Therefore, the smaller the value, the less the scattered light is transmitted and the less cloudy the material is.
Further, in the present invention, the transmittance (total light transmittance) is used as an index of transmittance. The transmittance is a ratio of the amount of transmitted light to the amount of light incident on the material to be measured, and is obtained as a value in consideration of reflection on the surface of the material and absorption inside the material.
In the present invention, the haze is measured according to JIS-K-7361: 2000, and "transparent" or "highly transparent" means that the haze is less than 5%. The haze is preferably less than 1%.
Further, in the present invention, the total light transmittance is measured by the method of JIS K7361-1, and high transmittance (excellent in transmittance) means that the transmittance is 99.0% or more.
Hereinafter, each component will be described in detail.

[(A) Urethane (meth) acrylate]
The curable composition of the present invention contains (A) urethane (meth) acrylate.
In addition, in this specification, (meth) acrylate is used as a generic term for acrylate and methacrylate, and includes either one or both of acrylate and methacrylate. The same is true for other similar expressions.
The urethane (meth) acrylate resin can be produced, for example, by synthesizing a urethane prepolymer with a polyol and a polyisocyanate and adding a (meth) acrylate having a hydroxyl group to the urethane prepolymer.
As the polyol, for example, known polyols such as hydrocarbon polyols, polyether polyols, polyester polyols, and polycarbonate polyols can be used. Further, as the polyisocyanate, for example, known polyisocyanates such as aromatic polyisocyanate, aliphatic polyisocyanate, aromatic aliphatic polyisocyanate, and alicyclic polyisocyanate can be used.
The curable composition of the present invention contains (A) urethane (meth) acrylate to obtain adhesion of the curable composition to the substrate, and further cures the curable composition to obtain a cured coating film. Flexibility is obtained and the possibility of peeling from the substrate is suppressed. If the number of (meth) acryloyl functional groups is too large, the crosslink density is high, the warpage of the cured product is large, and the toughness tends to be poor. Therefore, bifunctional and trifunctional ones are preferable.

In the present invention, a urethane resin having two (meth) acryloyl groups is particularly preferably used. Further, the weight average molecular weight of the bifunctional urethane (meth) acrylate is preferably in the range of 1500 to 20000. When the weight average molecular weight of the bifunctional urethane (meth) acrylate is 1500 or more, the curing shrinkage of the bifunctional urethane (meth) acrylate is reduced, and the cured product is less likely to warp. On the other hand, when the weight average molecular weight of the bifunctional urethane (meth) acrylate is 20000 or less, the viscosity is improved and the handleability in the composition preparation is improved.

Examples of commercially available bifunctional urethane (meth) acrylates include U-108A, U-200AX, UA-112P, UA-5201, U-340AX, UA-511, UA-512, and UA- manufactured by Shin-Nakamura Chemical Industries. 311, UA-412A, UA-4200, UA-4400, UA-340P, UA-2235PE, UA-160TM, UA-6100, U-108, UA-4000, UA-122P, UA-5201, UA-512, UA-W2, UA-7000, U-2PPA, UA-NDP; Sartmer CN962, CN963, CN964, CN965, CN980, CN981, CN982, CN983, CN996, CN9001, CN9002, CN9788, CN9893, CN978, CN9782, CN9783; M-1100, M-1200, M-1210, M-1310, M-1600 manufactured by Toa Synthetic Chemical Industry; Art Resins UN-99000PEP, UN-9200A, UN-7600, UN-333, UN-1255, manufactured by Negami Industrial Co., Ltd. UN-6060PTM, UN-6060P, SH-500B; AH-600, AT-600 manufactured by Kyoeisha Chemical Co., Ltd.;

Examples of commercially available products of trifunctional urethane (meth) acrylate include Evekryl 4513, Evekryl 4740, KRM8296, Evekryl 8296, and Evekryl 8311 manufactured by Daicel Ornex.

As the urethane (meth) acrylate, one of the above may be used, or a combination of a plurality of types may be used.

The amount of the urethane (meth) acrylate used (A) is preferably in the range of 30 to 40% by mass, particularly 34 to 36%, based on the total mass of the curable composition.
By using the above ratio (A) urethane (meth) acrylate, the adhesion to the substrate to which the curable composition is applied and the flexibility of the cured coating film are improved.

[(B) Thiocarboxylic acid derivative]
The curable composition of the present invention contains (B) a thiocarboxylic acid derivative in an amount of 50 parts by mass or more, preferably 60 to 120 parts by mass with respect to 100 parts by mass of (A) urethane (meth) acrylate.
In the present invention, the light transmittance of the cured coating film can be improved by containing the (B) thiocarboxylic acid derivative. (B) The thiocarboxylic acid derivative may be used alone or in combination of two or more.

で表される基を１〜６個有する化合物を挙げることができる。
その具体例としては、β-メルカプトプロピオン酸、２−エチルヘキシル−３-メルカプトプロピオネート、ｎ−オクチル-３−メルカプトプロピオネート、メトキシブチル−３−メルカプトプロピオネート、ステアリル-3-メルカプトプロピオネート、トリメチロールプロパン トリス（３−メルカプトプロピオネート）プロピオネート、ペンタエリスリトール テトラキス（３−メルカプトプロピオネート）、テトラエチレングリコール ビス（３−メルカプトプロピオネート）等の直鎖または分岐状の化合物、及びトリス−［（３−メルカプトプロピオニルオキシ）− エチル]−イソシアヌレートなどの環状構造を有する化合物を含むメルカプトプロピオン酸誘導体を挙げることができ、本発明ではトリス−［（３−メルカプトプロピオニルオキシ）− エチル]−イソシアヌレートが特に好ましく用いられる。 (B) As a thiocarboxylic acid derivative,

Examples thereof include compounds having 1 to 6 groups represented by.
Specific examples thereof include β-mercaptopropionic acid, 2-ethylhexyl-3-mercaptopropionate, n-octyl-3-mercaptopropionate, methoxybutyl-3-mercaptopropionate, and stearyl-3-mercaptopropionate. Linear or branched compounds such as pionate, trimetylolpropane tris (3-mercaptopropionate) propionate, pentaerythritol tetrakis (3-mercaptopropionate), tetraethylene glycol bis (3-mercaptopropionate) , And tris-[(3-mercaptopropionyloxy) -ethyl] -mercaptopropionic acid derivatives containing compounds having a cyclic structure such as isocyanurate, and in the present invention, tris-[(3-mercaptopropionyloxy) -Ethyl] -isocyanurate is particularly preferably used.

The amount of the thiocarboxylic acid derivative used (B) is preferably in the range of 25 to 40% by mass, particularly 30 to 38%, based on the total mass of the curable composition.
(B) When the amount of the thiocarboxylic acid derivative used is 25% by mass or more, sufficient light transmittance of the cured coating film can be obtained, and when it is 40% by mass or less, it is cured more than urethane (meth) acrylate alone. It is possible to obtain better adhesion of the sex composition to the substrate.

[(C) Triallyl Isocyanurate]
The curable composition of the present invention contains (C) triallyl isocyanurate in an amount of 40 parts by mass or more, preferably 45 to 95 parts by mass with respect to 100 parts by mass of (A) urethane (meth) acrylate.
In general, triallyl isocyanurate acts as a cross-linking aid and an adhesion-imparting agent in a curable composition by adding a small amount of about 10% by mass to the curable composition. However, in the present invention, by using (C) triallyl isocyanurate in an amount of 40 parts by mass or more, the haze value of the cured coating film can be lowered, the light transmittance can be made high, and heat resistance can be imparted.
The amount of triallyl isocyanurate (C) used is preferably in the range of 20 to 40% by mass, particularly 24 to 33%, based on the total mass of the curable composition.
(C) When the amount of triallyl isocyanurate used is 20% by mass or more, the hardness of the cured coating film can be made sufficient, and when it is 40% by mass or less, the transparency and the light transmittance are improved. It becomes particularly good, and heat resistance can be imparted.

[(D) Photopolymerization Initiator]
The curable composition of the present invention contains (D) a photopolymerization initiator. Examples of usable photopolymerization initiators include benzoins such as benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether; benzoin alkyl ethers; Benthraquinones such as benzophenone, p-methylbenzophenone, Michelers ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone; acetophenone, α-hydroxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone , 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone, N, N -Acetophenones such as dimethylaminoacetophenone; thioxanthons such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, Anthraquinones such as 2-ethylanthraquinone, 2-tert-butyl anthraquinone, 1-chloroanthraquinone, 2-amyl anthraquinone, 2-aminoanthraquinone; ketals such as acetphenone dimethyl ketal and benzyl dimethyl ketal; ethyl-4-dimethylaminobenzoate , 2- (Dimethylamino) ethylbenzoate, benzoic acid esters such as p-dimethylbenzoic acid ethyl ester; phenyldisulfide 2-nitrofluorene, butyroin, anthraquinone ethyl ether, azobisisobutyronitrile, tetramethylthium disulfide, etc. Can be mentioned.

The above (D) photopolymerization initiator can be used alone or in combination of two or more, but in order to improve the surface properties without impairing the flexibility of the cured product, α-hydroxyacetophenone-based photopolymerization initiator is initiated. It is preferable to use an agent.

The photopolymerization initiator (D) is added at a ratio of preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the urethane (meth) acrylate (A). ..

The total mass of the above-mentioned (A) urethane (meth) acrylate, the above-mentioned (B) thiocarboxylic acid derivative, and the above-mentioned (C) triallyl isocyanurate is preferably 95% or more of the total mass of the curable composition. As a result, the characteristics of high total light transmittance and well-suppressed cloudiness can be obtained.

A known and commonly used diluent, particularly a reactive diluent, can be used for adjusting the viscosity. In particular, a monofunctional (meth) acrylate compound, which is a compound having one ethylenically unsaturated group in the molecule, has a high dilution effect and is preferable.

[Other ingredients]
In addition to the above-mentioned components, components other than the above-mentioned components can be added to the curable composition of the present invention as long as the effects of the present invention are not impaired. Additives include photocurable monomers, silicone-based and fluorine-based defoamers, leveling agents, known and commonly used thermal polymerization inhibitors, UV absorbers, silane coupling agents, plasticizers, foaming agents, flame retardants, and antistatic agents. An inhibitor, an antistatic agent, an antibacterial / antifungal agent, etc. can be blended.

The curable composition of the present invention may contain a thermosetting component as long as it does not impair the desired properties, but generally does not use a thermosetting component. As a result, it is possible to obtain a cured product having more excellent transparency and light transmittance and having little change with time.

Since the curable composition of the present invention has high adhesion to the substrate, it can be easily and surely bonded to the substrate, and the durability of the equipment or parts to be bonded can be improved.

[Curing method of curable composition]
The curable composition of the present invention composed of the above-mentioned components can be made into a cured product by photocuring. At the time of curing, the curable composition is applied to a base material such as quartz glass and then irradiated with active energy rays to cure. The curable composition of the present invention preferably has a viscosity of 1 to 50 dPa · s.

As the coating method, any method such as a dip coating method, a flow coating method, a bar coater method, and a screen printing method can be applied. Further, as the irradiation light source of the active energy ray, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a metal halide lamp and the like are suitable. In addition, UV-LED, laser beam, electron beam and the like can also be used as active energy rays.

[Curing / molding method of curable composition]
Here, using a plate having recesses on the surface, the curable composition of the present invention is filled in the recesses, the filled curable composition is cured by ultraviolet rays, and the cured product is taken out from the recesses to form a molded product. The method of obtaining the above will be illustrated with reference to the drawings.

FIG. 1 shows a plate (1) having a recess (2) on its surface. Generally, a metal material such as stainless steel is used.

FIG. 2 shows a state (3) in which this plate is filled with the curable composition of the present invention. Generally, the curable composition is filled into the recesses of the plate using a doctor knife or the like.

FIG. 3 shows a step of covering the base material (4) from the upper part thereof and irradiating the light source (5) on the upper part with ultraviolet rays to cure the curable composition of the present invention. Generally, a transparent polyethylene terephthalate or polycarbonate film that transmits ultraviolet rays is used as the base material (4).

FIG. 4 shows a state in which the cured product is separated from the plate (1) to obtain a cured molded product (6). By using a known device dedicated to each of the series of steps of FIGS. 1 to 4, a molded product can be continuously manufactured.

As described above, the curable composition of the present invention can be molded and used in advance. In the molding method by photocuring while the recesses are filled, the thickness can be increased because the curing is not hindered by oxygen, and the thickness of the thickest portion can be 5 mm.
The curable composition of the present invention can also be applied to transparent screens such as touch panels, and as insulating materials such as solder resists, interlayer insulating materials, and coverlays. Further, the curable composition of the present invention may be applied as a solder dam. Furthermore, since the composition of the present invention has good adhesion, it can also be used as an adhesive, particularly a colorless and transparent adhesive used for transparent screens and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples, and the "parts" and "%" described below are all based on mass unless otherwise specified.

[Examples 1 to 10 and Comparative Examples 1 to 3]
Each component shown in Table 1 below was kneaded with a rotating / revolving mixer to prepare each curable composition.
Each of the obtained curable compositions was evaluated as follows.

1. 1. Printability Evaluation The curable compositions of Examples 1 to 10 and Comparative Examples 1 to 3 were cured to a thickness of 10 μm by a screen printing apparatus equipped with a 300 mesh printing plate made of polyester (Tetron (registered trademark)). The entire surface was printed on a quartz glass substrate so as to be.
The surface condition of the coating film 5 minutes after printing was visually observed and evaluated according to the following criteria. The results are shown in Table 1.

〇 The entire surface of the substrate is coated smoothly and evenly with the curable composition. × The surface of the curable composition shows traces of bursting bubbles, and the surface of the coating film is non-uniform.

2. 2. Evaluation of dryness to the touch (tack evaluation)
The curable compositions of Examples 1 to 10 and Comparative Examples 1 to 3 were entirely printed on a quartz glass substrate by a screen printing apparatus equipped with a 300 mesh printing plate made of polyester (Tetron (registered trademark)). .. The obtained coating film was exposed to a light amount of 1000 mJ / cm ² using a metal halide lamp to cure the coating film. The coating film (thickness 10 μm) thus obtained was used as a cured film for evaluation and evaluated according to the following criteria. The results are shown in Table 1.

◎ Even if you touch the coating film with your finger, no fingerprints will be attached to the surface of the coating film, and the coating film will not adhere to your fingers. Does not adhere × When the coating film is touched with a finger, a fingerprint is attached to the surface of the coating film, and the coating film further adheres to the finger.

3. 3. Pencil hardness evaluation Above 2. An effect film similar to the cured film for evaluation used in the evaluation of dryness to the touch was prepared, and the surface hardness thereof was measured using a pencil hardness tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.). In this test, each test piece was pressed with a 3H and 4H pencil sharpened so that the tip of the core was flat, at an angle of about 45 ° and with a load of 1 kg, and was 0.5 to 1 mm. By moving at least 7 mm at a speed of / s, the state of peeling of the distance coating film was evaluated according to the following criteria. The results are shown in Table 1.

◎ No peeling of the coating film with a 4H pencil 〇 No peeling of the coating film with a 3H pencil × Peeling of the coating film with a 3H pencil

4. Adhesion evaluation Above 3. Adhesion of the cured coating film (thickness 10 μm) similar to that used for pencil hardness evaluation is based on JIS K 5600-5-6, and a cross cut is made in a 10 mm x 10 mm grid pattern using a cross cut guide. A cross-cut tape peel ring test was performed by forming 100x100 grids. The remaining number of grids was visually observed according to the following criteria. The results are shown in Table 1.

〇 No peeling on the grid of the coating film × Peeling was observed on one or more of the grids of the coating film

5. Evaluation of total light transmittance Above 3. For a cured coating film (thickness 10 μm) similar to that used for pencil hardness evaluation, the total light transmittance is based on JIS K 7361-1, and the ultraviolet-visible spectrophotometer V-670EX (manufactured by JASCO Corporation). ) Was used.
In this evaluation, the ratio of transmitted light to incident light over the entire wavelength range of 300 to 780 nm used in the evaluation is shown. The measurement results are shown in Table 1.

6. Haze (cloudiness) evaluation Above 3. A cured coating film (thickness 10 μm) similar to that used for pencil hardness evaluation was measured by using an ultraviolet-visible spectrophotometer V-670EX (manufactured by JASCO Corporation) in accordance with JIS K 7136. As described in JIS K 7136, the haze is a value expressed as a percentage of the value obtained by dividing the scattered light transmittance of the test piece by the total light transmittance, and is a value of the total light transmittance. Was obtained in accordance with JIS K 7361-1. The measurement results are shown in Table 1.

7. Heat resistance test (total light transmittance and haze evaluation after heat treatment)
7-1. Preparation of heat-treated sample
Above 3. A heat-treated sample was prepared by storing a cured coating film similar to that used for pencil hardness evaluation in a hot air circulation type drying oven at a temperature of 100 ° C. for 2 hours.
7-2. Evaluation of total light transmittance and haze of the heat-treated sample The total light transmittance transmission and haze value of the heat-treated sample obtained by this are evaluated in the above 5. Evaluation of total light transmittance and 6. It was determined by the same measurement method as the haze (cloud value) evaluation. The measurement results are shown in Table 1.

8. Weather resistance test (total light transmittance and haze evaluation after exposure treatment)
8-1. Preparation of exposed sample
Above 3. An exposure-treated sample was prepared by subjecting a cured coating film similar to that used for pencil hardness evaluation to an entire surface with a light amount of 20 J / cm ² using a metal halide lamp.
8-2. Evaluation of total light transmittance and haze of the exposed sample The total light transmittance transmission and haze value of the exposed sample obtained by this are evaluated in the above 5. Evaluation of total light transmittance and 6. It was determined by the same measurement method as the haze (cloud value) evaluation. The measurement results are shown in Table 1.

Details of the materials listed in the table are shown below.
Evecryl 8402: Bifunctional urethane acrylate, photocurable urethane resin, Taisel Ornex Co., Ltd. TAIC: Triallyl cyanurate, Mitsubishi Chemical Co., Ltd. TEMPIC: Tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, Polymer (registered trademark) 184: 1-hydroxycyclohexyl-phenylketone manufactured by SC Organic Chemical Co., Ltd., KBM-5103: 3-acryloxypropyltrimethoxysilane manufactured by IGM Resins, light ester P-1M manufactured by Shinetsu Chemical Industry Co., Ltd .: Mono (2-hydroxyethyl methacrylate) phosphate, Floren AC-2300C manufactured by Kyoeisha Chemical Co., Ltd .: Olefin polymer (antifoaming agent), Polyflow KL-700 manufactured by Kyoeisha Chemical Co., Ltd .: Silicone-containing polymer (base material wetting agent), Kyoeisha Chemical Co., Ltd. Made by Co., Ltd.

From the above, it can be seen that the curable composition of the present invention is excellent in printability, and the cured product has excellent physical properties in all of the properties of touch-drying property, pencil hardness, and adhesion.
Further, the cured product of the present invention has a high light transmittance of 99.0% or more after exposure to the heat resistance test and after exposure to the weather resistance test, and the haze value is also the initial value and the heat resistance test exposure. Since it is suppressed to 1.5% or less both after and after exposure to the weather resistance test, the initial colorless and transparent beautiful state is used for a long period of time, especially as a transparent protective material for liquid crystal displays and touch panels. It can be seen that it is also resistant to.

The present invention is not limited to the configuration and examples of the above-described embodiment, and various modifications can be made within the scope of the gist of the invention.

1 ... Plate 2 ... Recess 3 ... Photocurable composition 4 ... Base material 5 ... Light source 6 ... Molded product

Claims (3)

(A) Urethane (meth) acrylate,
(B) Thiocarboxylic acid derivative,
(C) Triallyl isocyanurate, and (D) Photopolymerization initiator,
A curable composition comprising
50 parts by mass or more of the (B) thiocarboxylic acid derivative with respect to 100 parts by mass of the (A) urethane (meth) acrylate.
A curable composition comprising 40 parts by mass or more of the (C) triallyl isocyanurate with respect to 100 parts by mass of the (A) urethane (meth) acrylate. Claim 1 in which the total mass of the (A) urethane (meth) acrylate, the (B) thiocarboxylic acid derivative, and the (C) triallyl isocyanurate is 95% or more of the total mass of the curable composition. The curable composition according to description. A transparent cured product obtained from the curable composition according to claim 1 or 2.

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