JP6415107B2 - Resin molded body and its use - Google Patents

Description

  The present invention relates to a resin molded body obtained by photocuring a photocurable composition, and in particular, a sheet-shaped or film-shaped resin molded body, which is excellent in optical characteristics, thermal characteristics, and mechanical characteristics. In particular, the present invention relates to a resin molded body useful as a plastic substrate for a display and as a protective plate for a display.

  Conventionally, as a substrate for a display, a glass substrate is often used. For example, glass substrates having a thickness of about 0.3 to 1.1 mm are widely used in liquid crystal displays and organic electroluminescence (EL) displays. In recent years, plastic substrates have begun to be used from the viewpoint of weight reduction and thickness reduction and for the purpose of manufacturing flexible displays. In fact, there is a history of using polycarbonate or polyethersulfone as a substrate for liquid crystal displays. Such plastic substrates are not only optical performance such as light transmittance and birefringence, but also advanced processing such as thermomechanical properties such as heat resistance and bending strength, water absorption and specific gravity, chemical resistance and solvent resistance. Aptitude is required.

  In order to satisfy these various properties, many resins have been proposed regardless of thermoplasticity or thermosetting. Among recent proposals, a molded product obtained by photocuring a specific photocurable composition can be seen. For example, it is disclosed that by using a polymerizable composition containing a bifunctional (meth) acrylate and a mercapto compound having two or more thiol groups in the molecule, a resin molded body having low birefringence can be obtained. (For example, refer to Patent Document 1). Moreover, it is excellent in impact resistance by using a polymerizable composition containing a bifunctional (meth) acrylate, a mercapto compound having two or more thiol groups in the molecule, and a monofunctional (meth) acrylate. It is disclosed that a molded resin product can be obtained (for example, see Patent Document 2). Moreover, it is disclosed that a resin molded body having high heat resistance and low birefringence can be obtained by using a polymerizable composition containing 75 wt% or more of a tri- or higher functional aliphatic (meth) acrylate compound ( For example, see Patent Document 3.) Further, by using a polymerizable composition containing a bifunctional aliphatic (meth) acrylate compound and a tri- or higher functional (meth) acrylate compound, a molded article having high heat resistance and a small linear expansion coefficient can be obtained. (For example, refer to Patent Document 4).

  Further, a photocurable composition containing a monofunctional (meth) acrylate compound having an alicyclic structure, a polyfunctional urethane (meth) acrylate compound having an alicyclic structure, and a polyfunctional (meth) acrylate compound having an alicyclic structure. It is disclosed that a resin molded body having bending resistance can be obtained by using the composition (see, for example, Patent Document 5).

JP-A-9-152510 JP-A-11-222508 JP 2002-302517 A JP 2003-292545 A JP 2007-204736 A

  However, it is difficult to say that the various characteristics are balanced even with the disclosed techniques of Patent Documents 1 to 4, and in particular, satisfy the balance of physical properties such as heat resistance, flexibility and impact resistance of the resin molded body. That is a difficult task.

  Generally, in a display manufacturing process, a plastic substrate is heated to 150 ° C. or higher, but when a resin molded body is manufactured using a resin composition that forms a highly crosslinked structure with an emphasis on heat resistance, When a resin molded body is manufactured using a resin composition that forms a low cross-linked structure with the emphasis on flexibility and impact resistance, heat resistance is insufficient. Therefore, there is a problem that a high-performance display cannot be manufactured.

  In the technologies disclosed in Patent Documents 1 to 4, the heat resistance and rigidity are satisfactory because of the advanced cross-linking structure, but the inherent flexibility and impact resistance of the plastic are lost, and a falling ball equivalent to glass. Only impact strength was obtained.

  Furthermore, the technique disclosed in Patent Document 5 also has flexibility and good flex resistance, but is not satisfactory in impact resistance and is used as a protective plate. In this case, since the impact resistance becomes more important, further improvement is required.

  Therefore, in the present invention, under such a background, a resin molded article suitable for a flexible display, that is, a hardness sufficient to satisfy the heat resistance of the resin molded article, and it does not break even when bent or dropped. It is an object of the present invention to provide a resin molded product that satisfies both of sufficient flexibility to satisfy the falling ball impact strength.

ここで、Ｒ ₂ は炭素数１〜６のエーテル結合を含んでも良いアルキレン基、Ｒ ₃ は水素又はメチル基、ａは１又は２、ｂは０又は１である。
（Ｂ）脂環骨格を有する多官能ウレタン（メタ）アクリレート系化合物
（Ｃ）光重合開始剤
５．脂環骨格を有する多官能ウレタン（メタ）アクリレート系化合物（Ｂ）の重量平均分子量（Ｍ）と、該多官能ウレタン（メタ）アクリレート系化合物（Ｂ）の（メタ）アクリロイル基数（Ｎ）との比（Ｍ／Ｎ）が５００以上であること。
６．脂環骨格を有する多官能ウレタン（メタ）アクリレート系化合物（Ｂ）が、一般式（２）で示される脂環骨格をもつこと。

ここで、Ｒ ₁ は水素又はメチル基である。
However, as a result of intensive studies by the present inventors to solve the above-mentioned problems, a resin molded product obtained by photocuring the photocurable composition [I], which satisfies the following six conditions The present inventors have found that the molded body meets the above purpose and completed the present invention.
1. The glass transition temperature is 100 to 200 ° C.
2. The surface hardness in JIS K 5600-5-4: 1999 is H-4H.
3. When a steel ball having a weight of 130 g is dropped on the center of the surface of the resin molded body placed on a cylindrical base having a diameter of 32 mm using a falling ball tester, the following formula (α )
Y ≧ 40X (α)
Here, X is the thickness (mm) of the resin molded body, and Y is the maximum height (cm) at which the steel ball is not broken even when dropped.
4). The photocurable composition [I] contains the following components (A), (B) and (C).
(A) Bifunctional (meth) acrylate compound having an alicyclic skeleton represented by general formula (1)

Here, R ₂ is an alkylene group which may contain an ether bond having 1 to 6 carbon atoms, R ₃ is hydrogen or a methyl group, a is 1 or 2, and b is 0 or 1.
(B) Polyfunctional urethane (meth) acrylate compound having an alicyclic skeleton
(C) Photopolymerization initiator
5). The weight average molecular weight (M) of the polyfunctional urethane (meth) acrylate compound (B) having an alicyclic skeleton and the number of (meth) acryloyl groups (N) of the polyfunctional urethane (meth) acrylate compound (B) The ratio (M / N) is 500 or more.
6). The polyfunctional urethane (meth) acrylate compound (B) having an alicyclic skeleton has an alicyclic skeleton represented by the general formula (2).

Here, R ₁ is hydrogen or a methyl group.

  In the present invention, a display substrate using the resin molded body and a display protective plate are also provided.

  According to the present invention, it is possible to easily produce a resin molded article having excellent optical characteristics, thermal characteristics, mechanical characteristics, particularly excellent impact resistance, especially falling ball impact strength, and suitable for a flexible substrate for display. It is also suitable as a protective plate for touch panels and displays.

It is a figure explaining the falling ball test performed by this invention.

Hereinafter, the present invention will be described in detail.
In the present invention, “(meth) acrylate” is a general term for acrylate and methacrylate, and “(meth) acryloyl group” is a general term for acryloyl group and methacryloyl group.

ここで、Ｒ ₂ は炭素数１〜６のエーテル結合を含んでも良いアルキレン基、Ｒ ₃ は水素又はメチル基、ａは１又は２、ｂは０又は１である。
（Ｂ）脂環骨格を有する多官能ウレタン（メタ）アクリレート系化合物
（Ｃ）光重合開始剤
５．脂環骨格を有する多官能ウレタン（メタ）アクリレート系化合物（Ｂ）の重量平均分子量（Ｍ）と、該多官能ウレタン（メタ）アクリレート系化合物（Ｂ）の（メタ）アクリロイル基数（Ｎ）との比（Ｍ／Ｎ）が５００以上であること。
６．脂環骨格を有する多官能ウレタン（メタ）アクリレート系化合物（Ｂ）が、一般式（２）で示される脂環骨格をもつこと。

ここで、Ｒ ₁ は水素又はメチル基である。
The resin molded body of the present invention is a resin molded body obtained by photocuring the photocurable composition [I] and satisfies the following conditions.
1. The glass transition temperature is 100 to 200 ° C.
2. The surface hardness in JIS K 5600-5-4: 1999 is H-4H.
3. When a steel ball having a weight of 130 g is dropped on the center of the surface of the resin molded body placed on a cylindrical base having a diameter of 32 mm using a falling ball tester, the following formula (α )
Y ≧ 40X (α)
Here, X is the thickness (mm) of the resin molded body, and Y is the maximum height (cm) at which the steel ball is not broken even when dropped.
4). The photocurable composition [I] contains the following components (A), (B) and (C).
(A) Bifunctional (meth) acrylate compound having an alicyclic skeleton represented by general formula (1)

Here, R ₂ is an alkylene group which may contain an ether bond having 1 to 6 carbon atoms, R ₃ is hydrogen or a methyl group, a is 1 or 2, and b is 0 or 1.
(B) Polyfunctional urethane (meth) acrylate compound having an alicyclic skeleton
(C) Photopolymerization initiator
5). The weight average molecular weight (M) of the polyfunctional urethane (meth) acrylate compound (B) having an alicyclic skeleton and the number of (meth) acryloyl groups (N) of the polyfunctional urethane (meth) acrylate compound (B) The ratio (M / N) is 500 or more.
6). The polyfunctional urethane (meth) acrylate compound (B) having an alicyclic skeleton has an alicyclic skeleton represented by the general formula (2).

Here, R ₁ is hydrogen or a methyl group.

  In the present invention, the thickness of the resin molding is intended for a thickness that is used as a substrate or a protective plate for a normal liquid crystal display or organic EL display, and is usually 0.05 to 3 mm. It is preferably 0.1 to 2.5 mm, more preferably 0.2 to 2 mm, and particularly preferably 0.5 to 1 mm. The thickness of the resin molded product directly affects the flexibility of the plastic substrate. If the thickness is too thick, the flexibility tends to be lost. Conversely, if the thickness is too thin, the plastic molded body functions as a display support. There is a tendency to decrease, and the impact resistance tends to decrease.

Next, the glass transition temperature will be described.
The resin molded body of the present invention has a glass transition temperature of 100 to 200 ° C. from the viewpoint of display reliability, and preferably 120 to 190 ° C., particularly preferably 140 to 170 ° C. from the viewpoint of flexibility. If the glass transition temperature is too low, processability tends to be reduced, and if it is too high, cracking tends to occur.

The glass transition temperature was measured as follows.
That is, for example, using a tensile mode of a dynamic viscoelastic device “DVE-V4 type FT Rheospectr” manufactured by Rheology, measurement is performed at a frequency of 10 Hz, a temperature increase rate 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 is obtained, and the maximum peak temperature of tan δ is defined as the glass transition temperature (Tg).

Next, the surface hardness will be described.
The resin molded body of the present invention has a pencil hardness of H to 4H, preferably H to 3H, and more preferably H to 2H in terms of resistance to scratches. If the surface hardness is too soft, it tends to be damaged, and if it is too hard, it tends to break easily.
The pencil hardness is measured according to JIS K 5600-5-4: 1999.

Next, the falling ball impact strength will be described.
Naturally, in electronic device devices including flexible displays, a falling ball impact strength that must not be bent or broken when dropped is required. As an evaluation of the falling ball impact strength, it is preferable to drop a steel ball on a resin molded body and check for a crack using a falling ball tester as shown in FIG. The falling ball impact strength depends on the thickness of the resin molded body, but in the present invention, it is necessary to satisfy the above formula (α).

In the present invention, it is preferable that the following formula (β) is satisfied in terms of resistance to cracking, and it is particularly preferable that the following formula (γ) is satisfied.
Y ≧ 50X (β)
Y ≧ 70X (γ)
The maximum height Y that does not break even when the steel ball is dropped is preferably as high as possible, but generally the upper limit is about 200X.

  For example, when the thickness is 0.7 mm, it is preferable that the maximum height at which the four test pieces are not broken when a steel ball having a weight of 130 g is dropped onto the six test pieces is 30 cm or more. It is preferably 40 cm or more in terms of the strength of the flexible substrate for display, more preferably 50 cm or more in terms of the strength of the touch panel, and particularly preferably 60 cm or more in terms of the strength of the protective plate.

Here, the maximum value (Y) (cm) of the height at which a steel ball having a weight of 130 g is not broken is measured according to JIS R3206 in tempered glass as follows.
That is, after a test piece of a resin molded body having a length of 50 mm × width 50 mm was left in an environment of 23 ° C. and 50% RH for 48 hours, a test piece tester (manufactured by Toyo Seiki Seisakusho) as shown in FIG. A steel ball having a thickness of 130 g and a diameter of 31.73 mmφ is dropped from a predetermined height, and an impact is applied to the center of the surface of the test piece placed on a cylindrical table having a diameter of 32 mm. The predetermined height is increased in steps of 5 cm, and the same operation is performed on six test pieces at each height, and the maximum height (cm) at which four or more pieces are not broken is determined as a steel ball. It is measured as the maximum value (Y) of the height at which it does not break even if it is dropped.

  In the present invention, when adjusting the falling ball impact strength, that is, the maximum value (Y) of the height at which the steel ball is not broken even if dropped, the components (A), (B ) And (C), and a method of appropriately controlling the reaction rate of the (meth) acryloyl group.

  The resin molded body of the present invention is usually an acrylic resin obtained by photocuring, and is typically a resin molded body obtained by polymerizing acrylic monomers containing the following (A) to (C). . In this case, for example, the types and blending amounts of components (A), (B) and (C) are appropriately controlled, the reaction rate of (meth) acryloyl groups is controlled, and the thickness of the resin molded body is controlled. As a result, various physical properties such as the glass transition temperature, surface hardness, and falling ball impact strength can be adjusted. Especially, it is preferable to carry out by adjusting the composition of the photocurable composition constituting the resin molding.

The resin molded product having physical property values defined in the present invention includes the following components (A), (B), and (C).
It is intended to produce by photocuring a photocurable composition [I] comprising a.
(A) Bifunctional (meth) acrylate compound having an alicyclic skeleton represented by general formula (1)

（Ｂ）脂環骨格を有する多官能ウレタン（メタ）アクリレート系化合物
（Ｃ）光重合開始剤

(B) Polyfunctional urethane (meth) acrylate compound having an alicyclic skeleton (C) Photopolymerization initiator

The bifunctional (meth) acrylate compound having an alicyclic skeleton of the component (A) may be of the structure represented by the general formula (1), and R ₂ represents an ether bond having 1 to 6 carbon atoms. An alkylene group which may be contained, preferably an alkylene group having 1 to 4 carbon atoms, more preferably a methylene group or an ethylene group, R ₃ is hydrogen or a methyl group, preferably a methyl group, and a is 1 or 2 , B is 0 or 1. Since these bifunctional (meth) acrylate compounds having an alicyclic skeleton have an alicyclic skeleton, they contribute to a reduction in water absorption of the resin molded product.

Specific examples of the bifunctional (meth) acrylate compound (A) having an alicyclic skeleton include, for example, 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 (hydroxy Methyl) 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-((meth) acryloyloxy) cyclohexyl] propane, 2,2-bis [4- (β- (meth) acryloyloxyethoxy) cyclohexyl] propane 1,3-bis ((meth) acryloyloxymethyl) cyclohexane, 1,3-bis ((meth) acryloyloxyethyloxymethyl) cyclohexane, 1,4-bis ((meth) acryloyloxymethyl) cyclohexane, 1, Bifunctional (meth) acrylates such as 4-bis ((meth) acryloyloxyethyloxymethyl) cyclohexane may be mentioned. These are used alone or in combination. Among these, bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = diacrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] from the viewpoint of heat resistance. Decane = dimethacrylate is most preferred.

  The polyfunctional urethane (meth) acrylate compound having an alicyclic skeleton of component (B) is a urethane (meth) acrylate compound containing two or more (meth) acryloyl groups in the molecule.

  These monomers contribute to the falling ball impact strength which is the greatest feature of the present invention. Since the polyfunctional urethane (meth) acrylate compound (B) having an alicyclic skeleton is polyfunctional, the curing rate is improved and a resin molded product can be obtained with high productivity. Moreover, a crosslinked resin can be formed by photocuring and a resin molded body with high heat resistance can be obtained. Usually, as the polyfunctionality increases, the flexural modulus of the resin molded body increases and the flexibility is lost, and even if the impact resistance referred to in the present invention decreases, it becomes brittle, but the polyfunctional urethane (meth) having an alicyclic structure The acrylate compound (B) has a urethane group in the molecule, and the resulting resin molded body has appropriate toughness due to hydrogen bonding, and does not become brittle. Thus, a flexible resin molded article having excellent mechanical strength can be obtained.

  The number of functional groups in the component (B) is preferably 2 to 6 functional groups, particularly preferably 2 to 4 functional groups, and more preferably 2 to 3 functional (meth) acrylates, from the viewpoint of fast curing. preferable.

  In addition, the weight average molecular weight of the component (B) is preferably 500 to 20,000, particularly 1,000 to 10,000 in terms of physical properties. If the weight average molecular weight is too small, it tends to be hard and prone to cracking, and if it is too large, it tends to be too soft to lower the elastic modulus.

  In component (B), as one of the factors for improving the falling ball impact strength, it is presumed that the crosslinking density has an influence from the relationship between the number of functional groups and the molecular weight.

In the present invention, the weight average molecular weight (M) of the component (B) polyfunctional urethane (meth) acrylate compound having an alicyclic skeleton and the (meth) acryloyl group number (N) of the polyfunctional urethane (meth) acrylate compound And the ratio (M / N) of 500 or more is important in terms of physical properties, preferably 1,000 to 10,000, more preferably 1500 to 5,000, particularly preferably 2,000 to 3. , 000 is preferable. If the ratio (M / N) is too small, the crosslink density tends to be too high and tends to break, and if it is too large, the surface hardness tends to decrease.

  Here, the polyfunctional urethane (meth) acrylate compound (B) having the alicyclic skeleton includes, for example, a polyol compound, a polyisocyanate compound having an alicyclic skeleton, and a hydroxyl group-containing (meth) acrylate compound. If necessary, it can be obtained by reacting with a catalyst such as dibutyltin dilaurate.

  Examples of polyol compounds include aliphatic polyols, alicyclic polyols, polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, polybutadiene polyols, (meth) acrylic polyols, polysiloxane polyols, and the like. Is mentioned.

  Examples of the aliphatic polyol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, dimethylolpropane, neopentyl glycol, 2,2-diethyl-1,3-propanediol, and 2-butyl- 2-ethyl-1,3-propanediol, 1,4-tetramethylenediol, 1,3-tetramethylenediol, 2-methyl-1,3-trimethylenediol, 1,5-pentamethylenediol, 1,6 -Hexamethylenediol, 3-methyl-1,5-pentamethylenediol, 2,4-diethyl-1,5-pentamethylenediol, pentaerythritol diacrylate, 1,9-nonanediol, 2-methyl-1,8 -Two hydroxyl groups such as octanediol Examples thereof include aliphatic alcohols, sugar alcohols such as xylitol and sorbitol, and aliphatic alcohols containing three or more hydroxyl groups such as glycerin, trimethylolpropane, trimethylolethane, etc. More than one species can be used in combination.

  Examples of the alicyclic polyol include cyclohexanediols such as 1,4-cyclohexanediol and cyclohexyldimethanol, hydrogenated bisphenols such as hydrogenated bisphenol A, and tricyclodecane dimethanol. Two or more species can be used in combination.

  Examples of the polyether polyol include, for example, polyether glycols containing alkylene structures such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutylene glycol, polypentamethylene glycol, polyhexamethylene glycol, and the like. A random or block copolymer is mentioned.

  Examples of the polyester-based polyol include three types of components: a condensation polymer of a polyhydric alcohol and a polycarboxylic acid; a ring-opening polymer of a cyclic ester (lactone); a polyhydric alcohol, a polycarboxylic acid, and a cyclic ester. And the like.

  Examples of the polycarbonate-based polyol include a reaction product of a polyhydric alcohol and phosgene; a ring-opening polymer of a cyclic carbonate (such as alkylene carbonate).

  Examples of the polyolefin-based polyol include those having a homopolymer or copolymer such as ethylene, propylene, and butene as a saturated hydrocarbon skeleton, and having a hydroxyl group at the molecular end.

Examples of the polybutadiene-based polyol include those having a butadiene copolymer as a hydrocarbon skeleton and having a hydroxyl group at the molecular end.
The polybutadiene-based polyol may be a hydrogenated polybutadiene polyol in which all or part of the ethylenically unsaturated groups contained in the structure thereof are hydrogenated.

  Examples of the (meth) acrylic polyol include those having at least two hydroxyl groups in the molecule of the polymer or copolymer of the (meth) acrylic acid ester. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid alkyl esters such as 2-ethylhexyl acid, decyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, and the like.

  Examples of the polysiloxane-based polyol include dimethyl polysiloxane polyol and methylphenyl polysiloxane polyol.

  Among these, polyether polyols are preferably used in terms of resistance to cracking.

  The polyol compound preferably has a weight average molecular weight of 100 to 10,000, particularly 1,000 to 7,000, and more preferably 2,000 to 5,000. If the weight-average molecular weight of the polyol compound is too large, the surface hardness tends to decrease, and if it is too small, it tends to break easily.

Specific examples of the polyisocyanate compound having an alicyclic skeleton include, for example, isophorone diisocyanate, bis (isocyanatomethyl) tricyclo [5.2.1.0 ^2,6 ] decane, norbornane isocyanatomethyl, 1,3- Diisocyanatocyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-diisocyanatocyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, bis (4-isocyanatocyclohexyl) methane, 2, Examples thereof include 2-bis (4-isocyanatocyclohexyl) propane, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. Among these, isophorone diisocyanate and diisocyanate having an alicyclic skeleton represented by the following general formula (2) are preferable from the viewpoint of impact resistance, and specifically hydrogenated diphenylmethane diisocyanate is preferable.

ここで、Ｒ₁は水素又はメチル基である。

Here, R ₁ is hydrogen or a methyl group.

  Specific examples of the hydroxyl group-containing (meth) acrylate compound include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3- ( Examples include meth) acryloyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tri (meth) acrylate, and the like.

  The production method of the polyfunctional urethane (meth) acrylate compound (B) having the alicyclic skeleton is usually the above polyol compound, diisocyanate compound, and hydroxyl group-containing (meth) acrylate compound in a reactor or separately. The reaction product obtained by reacting a polyol compound and a diisocyanate compound in advance may be reacted with a hydroxyl group-containing (meth) acrylate compound to stabilize the reaction or to produce a by-product. This is useful in terms of reduction of objects.

  A known reaction means can be used for the reaction between the polyol compound and the diisocyanate compound. At that time, for example, the isocyanate group was left by setting the molar ratio of the isocyanate group in the diisocyanate compound to the hydroxyl group in the polyol to about 2n: (2n-2) (n is an integer of 2 or more). After obtaining the terminal isocyanate group-containing urethane (meth) acrylate compound, the addition reaction with the hydroxyl group-containing (meth) acrylate compound is enabled.

  Known reaction means can also be used for the addition reaction of the reaction product obtained by reacting the polyol compound and the diisocyanate compound in advance with a hydroxyl group-containing (meth) acrylate compound.

  Among the combinations of the above polyol-based compounds, polyisocyanate-based compounds, and hydroxyl group-containing (meth) acrylate-based compounds, bifunctionality that is a reaction product of polyether polyol, hydrogenated diphenylmethane diisocyanate, and 2-hydroxyethyl (meth) acrylate. Urethane acrylate is preferred from the viewpoint of heat resistance and falling ball impact strength.

  By copolymerizing the bifunctional (meth) acrylate compound of the component (A) and the urethane (meth) acrylate compound of the component (B) at a specific ratio, both heat resistance, flexibility and impact resistance are compatible. A molded resin product can be obtained.

  That is, it is preferable that the mixture ratio of a component (A) and a component (B) is 80: 20-50: 50 (weight ratio). If the amount of the component (B) is too small, mechanical properties such as impact resistance and flex resistance tend to be lowered. Conversely, if the amount of the component (B) is too large, the viscosity tends to increase and it is difficult to mold. A preferable range of the blending ratio is 70:30 to 55:45 (weight ratio), more preferably 65:35 to 58:42 (weight ratio).

  In the present invention, the photopolymerization initiator (C) is further blended. The photopolymerization initiator (C) is not particularly limited, but examples thereof include benzophenone, benzoin methyl ether, benzoin propyl ether, Ethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2 -Hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propyl) Pionyl) -benzyl] phenyl} -2-methyl-propan-1-one, phenylglyoxylic acid methyl ester, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) ) Phenyl] -1-butanone, 1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) ) -9H-carbazol-3-yl] -1- (0-acetyloxime) and the like. Among these, radical-cleavage photopolymerization initiators such as 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are preferable. These photopolymerization initiators may be used alone or in combination of two or more.

  The compounding quantity of a photoinitiator (C) is 0.01-5 weight part with respect to a total of 100 weight part of a component (A) and a component (B), Furthermore, 0.1-4 weight part, Especially 0 It is preferably 3 to 3 parts by weight. If the blending amount is too large, the retardation of the resin molded product increases and the light transmittance at 400 nm tends to decrease (yellowing). On the other hand, when the amount is too small, the polymerization rate is decreased, and the polymerization may not proceed sufficiently.

  In the present invention, a small amount of auxiliary components may be included as long as the physical properties of the resin molded body of the present invention are not impaired. For example, a monomer having an ethylenically unsaturated bond other than components (A) and (B), a chain transfer agent, a polymerization inhibitor, a thermal polymerization initiator, an ultraviolet absorber, an antioxidant, an antifoaming agent, a level There are ring agents, bluing agents, dyes and pigments and fillers.

  Examples of the monomer having an ethylenically unsaturated bond other than components (A), (B) and (C) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) ) Acrylate, C1-C20 alkyl (meth) acrylate such as 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) Acrylate, methoxypolyethylene glycol (meth) acrylate, undecylenoxy (meth) acrylate, undecylenoxypolyethylene glycol (meth) acrylate, behenyl (meth) acrylate, octoxypolyethylene glycol (meth) acrylate Rate, stearyl (meth) acrylate, isostearyl (meth) acrylate, monofunctional (meth) acrylate compounds such as lauryl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, Triethylene glycol di (meth) acrylate, di (meth) acrylate of polyethylene glycol higher than tetraethylene glycol, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol Di (meth) acrylate, 2-hydroxy 1,3-di (meth) acryloxypropane, trimethylolpropane tri (meth) acrylate, dipentaerythritol pentaacrylate monounde Examples thereof include polyfunctional (meth) acrylate compounds such as sylate, and (meth) acrylic acid derivatives such as acrylamide, methacrylamide, acrylonitrile, and methacrylonitrile.

  Known compounds can be used as the thermal polymerization initiator. For example, hydroperoxide such as hydroperoxide, t-butyl hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide Dialkyl peroxides such as t-butyl peroxybenzoate, peroxyesters such as t-butylperoxy (2-ethylhexanoate), diacyl peroxides such as benzoyl peroxide, and peroxycarbonates such as diisopropyl peroxycarbonate And peroxides such as peroxyketal and ketone peroxide.

  Examples of the chain transfer agent include polyfunctional mercaptan compounds. Examples of the polyfunctional mercaptan compound include pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, and the like. These polyfunctional mercaptan-based compounds are preferably used in a proportion of usually 10 parts by weight or less, more preferably 8 parts by weight or less, particularly 5 parts by weight with respect to 100 parts by weight of the photocurable composition [I]. Part or less is preferred. When there is too much this usage-amount, there exists a tendency for the heat resistance and rigidity of the resin molding obtained to fall.

Examples of the antioxidant include 2,6-di-t-butylphenol, 2,6-di-t-butyl-p-cresol, 2,4,6-tri-t-butylphenol, 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-tert-butyl-4- (N, N-dimethylaminomethyl) phenol, 3,5-di-tert-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-tert-butyl-4-hydroxyphenyl) propionate], bis (3,5-di-tert-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-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, calcium (3,5-di-tert-butyl-4-hydroxybenzyl) monoethyl phosphonate 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5-ditert-butyl-4-hydroxyphenyl) isocyanate Nurate, 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] methane, 3,5-di-t-butyl-4-hydroxybenzyl phosphite-diethyl Compounds such as esters may be used, and these compounds may be used alone or in combination of two or more thereof, among which tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate] methane is particularly preferred from the viewpoint of increasing the effect of suppressing hue.

  The blending ratio of the antioxidant is usually preferably 0.001 to 1 part by weight, particularly preferably 0.01 to 1 part by weight with respect to 100 parts by weight of the photocurable composition [I]. If the amount of such an antioxidant is too small, the light resistance of the resin molded product tends to decrease, and if it is too large, the light transmittance tends to decrease.

Thus, the photocurable composition [I] used in the present invention is obtained.
Next, the manufacturing method of the resin molding of this invention using this photocurable composition [I] is demonstrated.

As a manufacturing method of the resin molding in this invention, it is preferable to photocure the said photocurable composition [I] with the irradiation light quantity of 1-50 J / cm < ² > using the ultraviolet-ray with a wavelength of 200-400 nm. A more preferable range of the irradiation light amount is 5 to 40 J / cm ² , and further preferably 10 to 30 J / cm ² . When there is too much irradiation light quantity, there exists a tendency for productivity to fall. The illuminance of ultraviolet rays is preferably 10 to 5000 mW / cm ² , more preferably 100 to 1000 mW / cm ² . When the illuminance is too small, there is a tendency that the resin molded body is not sufficiently cured. On the other hand, when the illuminance is too high, polymerization tends to run away and retardation tends to increase. When the ultraviolet rays are irradiated in a plurality of times, a resin molded product with smaller retardation is obtained, which is preferable. For example, the method of irradiating about 1/100 to 1/10 of the total irradiation amount at the first time and irradiating the necessary remaining amount after the second time can be mentioned.

  Examples of the ultraviolet light source include a metal halide lamp, a high pressure mercury lamp, an electrodeless mercury lamp, and an LED lamp. The resin molded body obtained in the present invention may be heat-treated for improving the degree of polymerization or releasing stress strain, and is preferably heat-treated at 100 ° C. or higher, particularly 150 to 200 ° C.

  In general, photoforming is performed in a batch mode. That is, a mold in which two transparent glasses are opposed to each other through a spacer for controlling the thickness is prepared, and the photocurable composition [I] is injected into the cavity and cured by irradiation with active energy rays. And demolding.

Thus, the resin molded body of the present invention is obtained.
In the present invention, the flexural modulus of the obtained resin molding is preferably 1 to 4 GPa, more preferably 2 to 3.5 GPa, and further preferably 2.5 to 3 GPa. If the bending elastic modulus is too small, the rigidity of the resin molded body tends to be lowered and the function as a support tends to be lowered. If it is too large, the production of a flexible display tends to be difficult.

The light transmittance of the resin molded body is preferably 85% or more, particularly 90% or more, and more preferably 92% or more. If the light transmittance is too small, the luminance of the display device tends not to be ensured. The upper limit is 98%.
The light transmittance here is the total light transmittance in JIS K 7105: 1981.

  As a method of satisfying the light transmittance, the (meth) acrylate monomer constituting the photocurable composition [I] does not contain atoms and atomic groups such as aromatic rings, halogens, and sulfur. . These atoms and atomic groups are not preferable because the resin molded product has a high refractive index or a low refractive index. The light transmittance decreases because the surface reflection increases as the refractive index of the substrate increases.

  The haze of the resin molded body is preferably 1% or less, particularly 0.01 to 0.5%, more preferably 0.02 to 0.2%. If the haze is too large, the definition of the display tends to decrease.

  The retardation of the resin molding is a problem particularly in a liquid crystal display, and the retardation of the resin molding is preferably 2 nm or less, particularly 1.5 nm or less, more preferably 1 nm or less. If the retardation is too large, the polarized light that passes through the substrate cannot maintain its polarization characteristics, so that the image definition tends to deteriorate. The lower limit is 0.01 nm.

Examples of the method for satisfying the retardation include optimization of the viscosity of the photocurable composition [I] to be used for photoforming, reduction of the shrinkage of curing, and optimization of the amount of the photopolymerization initiator. As described above, optimization of viscosity and reduction of curing shrinkage are achieved by appropriately controlling the types and blending amounts of components (A), (B) and (C).
The retardation as used in the present invention is intended for the entire surface of a resin molded body cut for use as a substrate.

  Further, the surface roughness of the resin molded body affects the high definition of the display and, in particular, the life of the organic EL display. Even if a gas barrier film or a conductive film is formed on the surface of the resin molded body, the smoothness of the surface of the molded body is still important. The preferable range of the surface roughness Ra of the resin molded body is 50 nm or less, more preferably 20 nm or less. If the surface roughness Ra of the resin molded body is too large, the fineness and the life tend to decrease. The lower limit is 1 nm.

  The resin molded body of the present invention is a resin molded body having excellent optical characteristics, thermal characteristics, and mechanical characteristics, and is particularly useful as a display substrate, a touch panel substrate, and a display protective plate.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
In the examples, “parts” and “%” mean weight basis.

(1) Glass transition temperature (Tg) (° C)
Using a test piece of 20 mm in length and 5 mm in width, using a tensile mode of a dynamic viscoelastic device “DVE-V4 FT Rheospectr” manufactured by Rheology, a frequency of 10 Hz, a heating rate of 3 ° C./min, and a strain of 0 Measurements were made at 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 tan δ was defined as the glass transition temperature (Tg) (° C.).

(2) Surface hardness Pencil hardness was measured according to JIS K 5600-5-4: 1999.

(3) Falling ball test Based on JISR3206 in tempered glass, the maximum value (Y) of the height which does not break even if a steel ball was dropped was calculated | required as follows.
That is, a test piece of 50 mm length × 50 mm width was allowed to stand for 48 hours in an environment of 23 ° C. and 50% RH, and then used a falling ball tester (manufactured by Toyo Seiki Seisakusho) as shown in FIG. A steel ball having a diameter of 31.73 mm was dropped from a predetermined height, and an impact was applied to the center of the surface of the test piece placed on a cylindrical table having a diameter of 32 mm. The predetermined height is increased in steps of 5 cm, and the same operation is performed on six test pieces at each height, and the maximum height (cm) at which four or more pieces are not broken is determined as a steel ball. The maximum value (Y) of the height that does not break even when dropped.

(4) Flexural modulus (GPa)
A test piece of 30 mm length × 3 mm width was left for 48 hours in an environment of 23 ° C. and 50% RH, and then the flexural modulus (GPa) was measured by “FT-Rheospectra DVE-V4” manufactured by Rheology. In the measurement, the distance between fulcrums was adjusted to 20 mm, the test speed was 1.1 mm / second, and the deflection was 4 mm.

(5) Light transmittance (%)
Three test pieces each having a length of 50 mm and a width of 50 mm were prepared, and the total light transmittance (%) was measured with a Nippon Denshoku haze meter “NDH-2000”, and the average value of the three pieces was calculated.

(6) Haze (%)
Based on JIS K7361, it measured using Nippon Denshoku Industries Co., Ltd. haze meter "NDH-4000".

(7) Retardation (nm)
The measurement was performed at 25 ° C. using a birefringence measuring apparatus manufactured by Oak.

(8) Surface roughness Ra (nm)
In accordance with JIS B0601: 2001, the surface roughness Ra of the resin molded product was measured using “Surfcom 570A” manufactured by Tokyo Seimitsu Co., Ltd. (cutoff: 0.8 μm, measurement length: 4 mm).

<Example 1>
[Production of urethane acrylate (B-1) having a bifunctional alicyclic skeleton]
In a flask equipped with a thermometer, a stirrer, a water-cooled condenser and a nitrogen gas inlet, 373.0 g (1.42 mol) of dicyclohexylmethane diisocyanate, 462.0 g of polytetramethylene ether glycol (hydroxyl value 173 mg KOH / g) 0.71 mol), 0.01 g of dibutyltin dilaurate was added as a reaction catalyst and reacted at 60 ° C. for 8 hours. When the residual isocyanate group reached 7.1%, 165.0 g of 2-hydroxyethyl acrylate ( 1.42 mol), 0.01 g of hydroquinone methyl ether as a polymerization inhibitor was dropped over about 1 hour, the reaction was continued as it was, and the reaction was terminated when the residual isocyanate group became 0.3% or less, A urethane (meth) acrylate compound (B-1) was obtained.

[Preparation of Photocurable Composition [I-1]]
Bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = dimethacrylate (“DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.) 57 parts Urethane acrylate having a bifunctional alicyclic skeleton (B-1) (Ratio of the weight average molecular weight (M) of the polyfunctional urethane (meth) acrylate compound (B) and the number of (meth) acryloyl groups (N) of the polyfunctional urethane (meth) acrylate compound (B) (M / N) 2500) 40 parts, 3 parts of pentaerythritol tetrakisthiopropionate (“PET” manufactured by Sakai Chemical), 1 part of 1-hydroxycyclohexyl phenyl ketone (“Irgacure 184” manufactured by BASF Japan) at 60 ° C. The mixture was stirred until it became uniform to obtain a photocurable composition [I-1].

[Preparation of molded resin]
The photocurable composition [I] (23 ° C.) is poured into a mold using two polished glass plates facing each other and a 0.7 mm thick silicon plate as a spacer, and the illuminance is obtained using a metal halide lamp. Ultraviolet rays were irradiated at 200 W / cm ² and a light amount of 25 J / cm ² . After being cured by irradiation, the cured product obtained by demolding was heated in a vacuum oven at 200 ° C. for 6 hours to obtain a resin molded body having a length of 140 mm × width of 140 mm × thickness of 0.7 mm.
Each physical property of the obtained resin molded product was measured and shown in Table 2.

<Example 2>
A resin molded product having a length of 140 mm × width of 140 mm × thickness of 0.2 mm was obtained in the same manner as in Example 1, except that the thickness was changed to 0.2 mm.
Each physical property of the obtained resin molded product was measured and shown in Table 2.

<Example 3>
In Example 1, it carried out similarly except having changed photocurable composition [I] into the following photocurable composition [I-2], and obtained the resin molding.
Each physical property of the obtained resin molded product was measured and shown in Table 2.

[Preparation of Photocurable Composition [I-2]]
49 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane diacrylate (“A-DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.), bis (hydroxymethyl) tricyclo [5.2.1. 0 ^2,6 ] decane = dimethacrylate (“DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.) 10 parts urethane acrylate (B-1) having a bifunctional alicyclic skeleton (polyfunctional urethane (meth) acrylate compound (B) The ratio (M / N) of the weight average molecular weight (M) of the polyfunctional urethane (meth) acrylate compound (B) to the number of (meth) acryloyl groups (N) is 2500) 20 parts. Urethane acrylate (B-2) having an alicyclic skeleton (weight average molecular weight (M) of polyfunctional urethane (meth) acrylate compound (B) and the polyfunctional urethane (meth) acrylate compound) The ratio (M / N) of the product (B) to the (meth) acryloyl group number (N) is 240) 20 parts, pentaerythritol tetrakisthiopropionate (“PETP” manufactured by Sakai Chemical) 1 part, 2, 4 , 6-Trimethylbenzoyldiphenylphosphine oxide (BASF Japan "Lucirin TPO") 0.04 part, benzophenone (Kanto Chemical Co., Ltd.) 0.25 part, stirred at 60 ° C until uniform, photocured Sex composition [I-2] was obtained.

[Urethane acrylate (B-2): Preparation of bifunctional urethane acrylate having an isophorone structure]
In a four-necked flask equipped with a thermometer, stirrer, water-cooled condenser and nitrogen gas inlet, 53.34 g (0.24 mol) of isophorone diisocyanate, 55.73 g (0.48 mol) of 2-hydroxypropyl acrylate, hydroquinone 0.02 g of methyl ether, 0.02 g of dibutyltin dilaurate, and 500 g of methyl ethyl ketone were added and reacted at 60 ° C. for 3 hours. When the residual isocyanate group became 0.3%, the reaction was terminated, and the solvent was distilled off to obtain urethane. An acrylate (B-2) was obtained.

<Comparative Example 1>
In Example 1, it carried out similarly except having changed photocurable composition [I] into the following photocurable composition [I'-1], and obtained the resin molding.
Each physical property of the obtained resin molded product was measured and shown in Table 2.
The obtained resin molding had a surface hardness of 5H and a heat resistance of 250 ° C., but the maximum height at which it did not break in the falling ball test was 20 cm, which was inferior in impact resistance.

[Preparation of Photocurable Composition [I′-1]]
87 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = dimethacrylate (“DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.), urethane acrylate having the following hexafunctional alicyclic skeleton (B- 3) (Ratio of the weight average molecular weight (M) of the polyfunctional urethane (meth) acrylate compound (B) and the number of (meth) acryloyl groups (N) of the polyfunctional urethane (meth) acrylate compound (B) ( M / N) is 233) 10 parts, 3 parts of pentaerythritol tetrakisthiopropionate (“PET” manufactured by Sakai Chemical), 1 part of 1-hydroxycyclohexyl phenyl ketone (“Irgacure 184” manufactured by Ciba Specialty Chemicals) It stirred until it became uniform at 60 degreeC, and photocurable composition [I'-1] was obtained.

[Production of urethane acrylate (B-3) having a hexafunctional alicyclic skeleton]
In a flask equipped with a thermometer, stirrer, water-cooled condenser and nitrogen gas inlet, 192.0 g (0.86 mol) of isophorone diisocyanate and pentaerythritol triacrylate [mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (hydroxyl group) 808.0 g (1.73 mol), 0.01 g of hydroquinone methyl ether as a polymerization inhibitor and 0.01 g of dibutyltin dilaurate as a reaction catalyst, reacted at 60 ° C. for 8 hours, and the remaining isocyanate The reaction was terminated when the group became 0.3% or less to obtain a urethane (meth) acrylate compound (B-3).

<Comparative example 2>
In Example 1, it carried out similarly except having changed photocurable composition [I] into the following photocurable composition [I'-2], and obtained the resin molding.
Each physical property of the obtained resin molded product was measured and shown in Table 2.
The obtained resin molded body had a surface hardness of 7H and a heat resistance of 250 ° C., but the maximum value of the height at which it did not break in the falling ball test was 25 cm, and was inferior in impact resistance.

[Preparation of Photocurable Composition [I′-2]]
67 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane dimethacrylate (“DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.), urethane acrylate having a hexafunctional alicyclic skeleton (B-3) (Ratio of the weight average molecular weight (M) of the polyfunctional urethane (meth) acrylate compound (B) and the number of (meth) acryloyl groups (N) of the polyfunctional urethane (meth) acrylate compound (B) (M / N) 233) 30 parts, 3 parts of pentaerythritol tetrakisthiopropionate (“PET” manufactured by Sakai Chemical), 1 part of 1-hydroxycyclohexyl phenyl ketone (“Irgacure 184” manufactured by Ciba Specialty Chemicals), 60 ° C. To obtain a photocurable composition [I′-2].

<Comparative Example 3>
In Example 1, it carried out similarly except having changed photocurable composition [I] into the following photocurable composition [I'-3], and obtained the resin molding.
Each physical property of the obtained resin molded product was measured and shown in Table 2.
The obtained resin molded body had a surface hardness of 6H and heat resistance of 250 ° C., but the maximum height at which it did not break in the falling ball test was 20 cm, which was inferior in impact resistance.

[Preparation of Photocurable Composition [I′-3]]
67 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane dimethacrylate ("DCP" manufactured by Shin-Nakamura Chemical Co., Ltd.), urethane acrylate having the following hexafunctional alicyclic skeleton (B- 4) (Ratio of the weight average molecular weight (M) of the polyfunctional urethane (meth) acrylate compound (B) and the (meth) acryloyl group number (N) of the polyfunctional urethane (meth) acrylate compound (B) ( M / N) is 367) 30 parts, 3 parts of pentaerythritol tetrakisthiopropionate (“PET” manufactured by Sakai Chemical), 1 part of 1-hydroxycyclohexyl phenyl ketone (“Irgacure 184” manufactured by Ciba Specialty Chemicals), It stirred until it became uniform at 60 degreeC, and photocurable composition [I'-3] was obtained.

[Production of urethane acrylate (B-4) having a hexafunctional alicyclic skeleton]
In a flask equipped with a thermometer, a stirrer, a water-cooled condenser and a nitrogen gas inlet, 219.0 g (0.84 mol) of dicyclohexylmethane diisocyanate and pentaerythritol triacrylate [mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate ( Hydroxyl value 120 mgKOH / g)] 781.0 g (1.67 mol) was charged, hydroquinone methyl ether 0.01 g as a polymerization inhibitor, and dibutyltin dilaurate 0.01 g as a reaction catalyst, reacted at 60 ° C. for 8 hours, and remained. The reaction was terminated when the isocyanate group became 0.3% or less to obtain a urethane (meth) acrylate compound (B-4).

<Comparative example 4>
A commercially available polycarbonate film (“Panlite” manufactured by Teijin DuPont) having a length of 140 mm × width of 140 mm × thickness of 0.7 mm was prepared as a substrate.
The polycarbonate film was measured for the same physical properties as in Example 1, and shown in Table 2.
The polycarbonate film had a heat resistance of 140 ° C., and the maximum height at which it could not be broken in the falling ball test was 100 cm or more. However, the surface hardness was as low as B, and it was not practically usable as a substrate.

<Comparative Example 5>
As a substrate, a commercially available polymethyl methacrylate film (“Acrylite” manufactured by Mitsubishi Rayon Co., Ltd.) having a length of 140 mm × width of 140 mm × thickness of 0.7 mm was prepared.
The polymethyl methacrylate film was measured for the same physical properties as in Example 1 and shown in Table 2.
The polymethylmethacrylate film has a low heat resistance of 80 ° C., the maximum height at which it does not break in the falling ball test is 10 cm, is inferior in impact resistance, and was not practically usable as a substrate.

<Comparative Example 6>
A commercially available tempered glass ("Gorilla Glass" manufactured by Corning) having a length of 150 mm, a width of 150 mm, and a thickness of 0.55 mm was prepared as a substrate.
Using the tempered glass, the same physical properties as in Example 1 were measured and shown in Table 2.
The maximum value of the height at which the tempered glass does not break in the falling ball test is 15 cm, which is inferior in impact resistance, and was not practically usable as a substrate.

  The results of Examples and Comparative Examples are shown in Tables 1 and 2.

The resin molded bodies of the examples have excellent performance in the glass transition temperature, surface hardness, and falling ball test, and are excellent as plastic substrates and protective plates, whereas Comparative Examples 1 to 3 The resin molded product had a low maximum height that could not be broken in the ball drop test, and was inferior in impact resistance.
Further, in Comparative Examples 4 to 6 using a commercially available plastic film, both high surface hardness and resistance to cracking cannot be achieved, which is not satisfactory in practical use.

  The resin molded body of the present invention can be advantageously used for various optical materials and electronic materials. For example, liquid crystal substrates, organic / inorganic EL substrates, electronic paper substrates, light guide plates, phase difference plates, touch panels, optical filters, various display members, optical disc substrates and other storage / recording applications, thin film battery substrates, It can be used for energy applications such as solar cell substrates, optical communication applications such as optical waveguides, functional films and sheets, and various optical films and sheets.

Claims (9)

A resin molded product obtained by photocuring the photocurable composition [I], which satisfies the following six conditions.
1. The glass transition temperature is 100 to 200 ° C.
2. The surface hardness in JIS K 5600-5-4: 1999 is H-4H.
3. When a steel ball having a weight of 130 g is dropped on the center of the surface of the resin molded body placed on a cylindrical base having a diameter of 32 mm using a falling ball tester, the following formula (α )
Y ≧ 40X (α)
Here, X is the thickness (mm) of the resin molded body, and Y is the maximum height (cm) at which the steel ball is not broken even when dropped.
4). The photocurable composition [I] contains the following components (A), (B) and (C).
(A) Bifunctional (meth) acrylate compound having an alicyclic skeleton represented by general formula (1)

Here, R ₂ is an alkylene group which may contain an ether bond having 1 to 6 carbon atoms, R ₃ is hydrogen or a methyl group, a is 1 or 2, and b is 0 or 1.
(B) Polyfunctional urethane (meth) acrylate compound having an alicyclic skeleton
(C) Photopolymerization initiator
5). The weight average molecular weight (M) of the polyfunctional urethane (meth) acrylate compound (B) having an alicyclic skeleton and the number of (meth) acryloyl groups (N) of the polyfunctional urethane (meth) acrylate compound (B) The ratio (M / N) is 500 or more.
6). The polyfunctional urethane (meth) acrylate compound (B) having an alicyclic skeleton has an alicyclic skeleton represented by the general formula (2).

Here, R ₁ is hydrogen or a methyl group. The resin molded article according to claim 1, wherein the thickness is 0.05 to 3 mm. The resin molded product according to claim 1 or 2 , wherein the flexural modulus is 1 to 4 GPa. The resin molded product according to any one of claims 1 to 3, wherein the light transmittance is 85% or more. The resin molded body according to any one of claims 1 to 4 , wherein the haze is 1% or less. Retardation is 2 nm or less, The resin molding in any one of Claims 1-5 characterized by the above-mentioned. Claim 1-6 resin molding according to any one, characterized in that at least one side of the surface roughness Ra of 50nm or less. Display substrate characterized by comprising using the claim 1-7 resin molding according to any one. Display protective plate characterized by comprising using the claim 1-7 resin molding according to any one.

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