JP6440944B2 - Photocurable composition and molded article - Google Patents

Description

  The present invention relates to a photocurable composition and a molded product, and more particularly to a photocurable composition having excellent curability and a molded product obtained from the composition.

  Cured products obtained by curing photocurable compositions containing photocurable resins are used as signs for electronic devices and mobile phones, decorations that enhance visibility and aesthetics, buttons on panels, switch members, cushioning materials, etc. Has been. Since such a cured product can be cured and molded by irradiating the photocurable composition filled in the plurality of concave portions formed on the plate surface with light, a large number of molded products can be easily produced at a time. There is an advantage that it is possible.

  An active energy ray-curable resin composition containing, for example, a bifunctional urethane (meth) acrylate resin, isobornyl (meth) acrylate, and a photopolymerization initiator has been proposed as a resin composition used for the above applications (patent) Reference 1).

JP 2008-24803 A

  In recent years, further improvement in the curability of the photocurable composition has been demanded from the viewpoint of productivity improvement and energy saving. Moreover, depending on a use and the objective, it is necessary to mix | blend components, such as a coloring agent which worsens sclerosis | hardenability, and sufficient sclerosis | hardenability might not be obtained.

  Then, the objective of this invention is providing the photocurable composition excellent in sclerosis | hardenability, and the molded article obtained from this composition.

  As a result of intensive studies to solve the above problems, the present inventors have found that at least two photoreactive monomers having different numbers of functional groups, a photopolymerization initiator that is a compound having at least two ultraviolet absorbers and an ether structure. It has been found that the above problems can be solved by using it, and the present invention has been completed.

（式中、ＲおよびＲ´はそれぞれ独立して紫外線吸収団を表し、ｌ_１は２〜４の整数、ｍ_１は１以上の整数を表す。） That is, the photocurable composition of the present invention comprises (A) a photocurable resin, (B) a photopolymerization initiator represented by the following general formula (I), and (C) at least two different functional groups. The photoreactive monomer is included.

(In the formula, R and R ′ each independently represent an ultraviolet absorber, l ₁ represents an integer of 2 to 4, and m ₁ represents an integer of 1 or more.)

  The photocurable composition of the present invention is preferably a (meth) acrylate monomer in which at least one of the (C) at least two photoreactive monomers having different functional groups is monofunctional.

  Moreover, it is preferable that the photocurable composition of this invention contains (D) coloring agent further.

  Moreover, it is preferable that the photocurable composition of the present invention is used in a molding method in which the photocurable composition is cured by irradiating active energy rays in a state where the recess is filled, and does not contain an organic solvent.

  The molded article of the present invention is formed by molding the above-mentioned photocurable resin composition.

  According to this invention, it becomes possible to provide the photocurable composition excellent in sclerosis | hardenability, and the molded article obtained from this composition by setting it as the said structure.

It is a schematic diagram showing the plate body provided with the recessed part used for preparation of the molded article of this invention. It is a schematic diagram showing the state which filled the recessed part of the plate body with the photocurable composition of this invention. It is a schematic diagram showing the process of covering a printing plate with a base material and irradiating ultraviolet rays from a light source located above. It is a schematic diagram showing the state which released the base material and the molded product from the plate body.

（式中、ＲおよびＲ´はそれぞれ独立して紫外線吸収団を表し、ｌ_１は２〜４の整数、ｍ_１は１以上の整数を表す。）
上記のような構成とすることにより、硬化性に優れる光硬化性組成物とすることができる。また、前記（Ｃ）官能基数が異なる少なくとも２種の光反応性モノマーのうち、少なくとも１種を１官能の（メタ）アクリレートモノマーとすることによって、硬化物の低反り性に優れる光硬化性組成物とすることができる。
以下、各成分について詳細に説明する。 The photocurable composition of the present invention comprises (A) a photocurable resin, (B) a photopolymerization initiator represented by the following general formula (I), and (C) at least two types of light having different numbers of functional groups. It contains a reactive monomer.

(In the formula, R and R ′ each independently represent an ultraviolet absorber, l ₁ represents an integer of 2 to 4, and m ₁ represents an integer of 1 or more.)
By setting it as the above structures, it can be set as the photocurable composition excellent in sclerosis | hardenability. Moreover, the photocurable composition which is excellent in the low curvature property of hardened | cured material by making at least 1 type into a monofunctional (meth) acrylate monomer among the at least 2 types of photoreactive monomers from which the said (C) functional group number differs It can be a thing.
Hereinafter, each component will be described in detail.

[(A) Photocurable resin]
The photocurable resin contained in the photocurable composition of the present invention may be a resin that is cured by ultraviolet irradiation, and is preferably a prepolymer (oligomer or polymer) having one or more ethylenically unsaturated bonds in the molecule. ). Moreover, (A) photocurable resin can also be said to be a component except (C) photoreactive monomer.
Examples of the prepolymer include unsaturated polyester oligomers and (meth) acrylate oligomers. Examples of (meth) acrylate oligomers include phenol novolac epoxy (meth) acrylate, cresol novolac epoxy (meth) acrylate, epoxy (meth) acrylates such as bisphenol type epoxy (meth) acrylate, urethane (meth) acrylate, epoxy urethane (meta ) Acrylate, polyester (meth) acrylate, polyether (meth) acrylate, polybutadiene-modified (meth) acrylate, and the like.

Among the prepolymers, urethane (meth) acrylate and polyester (meth) acrylate are preferable. Urethane (meth) acrylate contains one or more (meth) acryloyloxy groups and contains a plurality of urethane bonds. The urethane (meth) acrylate 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 thereto.
As the polyol, known polyols such as hydrocarbon polyols, polyether polyols, polyester polyols, and polycarbonate polyols can be used without particular limitation. As the polyisocyanate, known polyisocyanates such as aromatic polyisocyanate, aliphatic polyisocyanate, aromatic aliphatic polyisocyanate, alicyclic polyisocyanate and the like can be used without particular limitation.
If the number of functional groups is too large, the crosslink density increases, the warp of the cured product tends to increase, and the toughness tends to deteriorate. Moreover, it is preferable that (A) at least 2 types of urethane (meth) acrylates from which a structure differs are included as photocurable resin. Examples of commercially available urethane (meth) acrylate include EBECRYL8402 manufactured by Daicel-Cytec.

Polyester (meth) acrylate is a terminal (meth) acrylic ester of polyester. For example, polyester polyol obtained by reacting polyol (polyhydric alcohol) and polycarboxylic acid, (meth) acrylic acid, What reacted (meth) acrylic acid derivatives, such as 2-hydroxy (meth) acrylate, is mentioned. Examples of the polyol include those described above. Examples of the polyvalent carboxylic acid include aliphatic polyvalent carboxylic acids such as adipic acid and maleic acid, alicyclic polyvalent carboxylic acids such as 1,4-cyclohexanedicarboxylic acid, and aromatic polyvalent carboxylic acids such as phthalic acid and trimellitic acid. Known polyvalent carboxylic acids such as carboxylic acids can be used without particular limitation.
If the number of functional groups is too large, the crosslink density increases, the warp of the cured product tends to increase, and the toughness tends to deteriorate. Examples of commercially available polyester acrylates include EBECRYL860 and EBECRYL1870 manufactured by Daicel Cytec.

  (A) The weight average molecular weight of photocurable resin becomes like this. Preferably it is 1000-20000. When the weight average molecular weight is 1000 or more, the crosslinking density caused by the photocurable resin having a plurality of ethylenically unsaturated groups does not become too high, and the curing shrinkage of the resin is reduced to reduce the warpage of the cured product. Can do. On the other hand, when the weight average molecular weight is 20000 or less, the viscosity of the composition does not become too high, and the handleability becomes good.

（式中、ＲおよびＲ´はそれぞれ独立して紫外線吸収団を表し、ｌ_１は２〜４の整数、ｍ_１は１以上の整数を表す。） [(B) Photopolymerization initiator]
The photocurable composition of this invention contains the photoinitiator represented by the following general formula (I) as (B) component.

(In the formula, R and R ′ each independently represent an ultraviolet absorber, l ₁ represents an integer of 2 to 4, and m ₁ represents an integer of 1 or more.)

  In the general formula (I), the ultraviolet absorber represented by R and R ′ means a molecular structure of the photopolymerization initiator that generates free radicals (or free cations) upon irradiation with ultraviolet rays. If it is a well-known ultraviolet absorber, it will not specifically limit. Here, the ultraviolet rays are electromagnetic waves having a wavelength of 10 to 400 nm. Examples of ultraviolet absorbers include amino ketones such as α-amino ketones, anthraquinones, thioxanthones, ketals, benzophenones, xanthones, acetophenones, benzoins, thioxanthones, benzoates, and the like.

The ultraviolet absorber is preferably a structure represented by any of the following formulas (II) to (VII).

In the general formula (I), l ₁ is preferably 2 or 4, m ₁ is preferably an integer of ₁ to 5, more preferably an integer of 1 to 3, and 1. Is particularly preferred.

  The photopolymerization initiator represented by the general formula (I) is preferably liquid at room temperature. Here, liquid at room temperature is 90 to 90 mm from the bottom when the sample is placed in a test tube having an inner diameter of 30 mm up to a height of 55 mm and the test tube is leveled at any temperature of 10 to 40 ° C. A state that is within seconds.

  Examples of the photopolymerization initiator represented by the general formula (I) include a diester of carboxymethoxy-benzophenone and polytetramethylene glycol 250, a polymer benzophenone derivative, a diester of carboxymethoxythioxanthone and polytetramethylene glycol 250, polyethylene Glycol (200) di (β- (4- (acetylphenyl) piperazine)) propionate, poly (ethylene glycol) bisdimethylaminobenzoate, polyethylene glycol (200) di (β-4- [4- (2-dimethylamino- 2-benzyl) butanoylphenyl] piperazine) propionate, carboxymethoxybenzophenone and diester of polyethylene glycol 200, and the like.

  Examples of the photopolymerization initiator represented by the general formula (I) include compound Nos. Represented by the following formulas. 1-7 are mentioned. However, the present invention is not limited by the following compounds.

（式中、ｎ_１は１以上の整数を表す。）
ｎ_１は１〜５の整数であることが好ましく、１〜３の整数であることがより好ましく、１であることが特に好ましい。

(In the formula, n ₁ represents an integer of 1 or more.)
n ₁ is preferably an integer of ₁ to 5, more preferably an integer of 1 to 3, and particularly preferably 1.

（式中、ｎ_２は１以上の整数を表す。）
ｎ_２は１〜５の整数であることが好ましく、１〜３の整数であることがより好ましく、１であることが特に好ましい。

(In the formula, n ₂ represents an integer of 1 or more.)
n ₂ is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and particularly preferably 1.

（式中、ｎ_３は１以上の整数を表す。）
ｎ_３は１〜５の整数であることが好ましく、１〜３の整数であることがより好ましく、１であることが特に好ましい。

(In the formula, n ₃ represents an integer of 1 or more.)
n ₃ is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and particularly preferably 1.

（式中、ｎ_４は１以上の整数を表す。）
ｎ_４は１〜５の整数であることが好ましく、１〜３の整数であることがより好ましく、１であることが特に好ましい。

(In the formula, n ₄ represents an integer of 1 or more.)
n ₄ is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and particularly preferably 1.

（式中、ｎ_５は１以上の整数を表す。）
ｎ_５は１〜５の整数であることが好ましく、１〜３の整数であることがより好ましく、１であることが特に好ましい。

(In the formula, n ₅ represents an integer of 1 or more.)
n ₅ is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and particularly preferably 1.

（式中、ｎ_６は１以上の整数を表す。）
ｎ_６は１〜５の整数であることが好ましく、１〜３の整数であることがより好ましく、１であることが特に好ましい。

(In the formula, n ₆ represents an integer of 1 or more.)
n ₆ is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and particularly preferably 1.

（式中、ｎ_７は１以上の整数を表す。）
ｎ_７は１〜５の整数であることが好ましく、１〜３の整数であることがより好ましく、１であることが特に好ましい。）

(In the formula, n ₇ represents an integer of 1 or more.)
n ₇ is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and particularly preferably 1. )

  As an example of the commercial item of the photoinitiator represented by the said general formula (I), Omnipol BP, Omnipol 2702, Omnipol TX, Omnipol SZ, Omnipol ASA, Omnipol 910, Omnipol 9210, Omnipol 9210, manufactured by IHT Co., Ltd. Omnipol 682 etc. are mentioned.

  The photopolymerization initiator represented by the general formula (I) may be used alone or in combination of two or more. Moreover, you may mix another photoinitiator in the range which does not impair the effect of this invention. The photopolymerization initiator represented by the above general formula (I) is preferably 0.5 to 10 parts by mass, more preferably 1 to 9 parts by mass, and more preferably 100 parts by mass of (A) the photocurable resin. Preferably it is contained at a ratio of 2 to 8 parts by mass. When the photopolymerization initiator represented by the general formula (I) is 0.5 part by mass or more, curability is improved. On the other hand, when the photopolymerization initiator represented by the general formula (I) is 10 parts by mass or less, adhesion and the like are improved.

[(C) At least two types of photoreactive monomers having different functional groups]
The photocurable composition of the present invention contains at least two photoreactive monomers having different functional groups as the component (C). A photoreactive monomer is a monomer having one or more ethylenically unsaturated groups and is used as a reactive diluent. Any known photoreactive monomer can be used. For example, hydroxyalkyl acrylates such as 2-hydroxymethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate; isobornyl acrylate, tetrahydrofurfuryl acrylate, N-acryloylmorpholine, N-vinyl Monofunctional photosensitive monomers having a cyclic skeleton such as pyrrolidinone; Mono- or diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, propylene glycol; N, N-dimethylacrylamide, N-methylolacrylamide, N Acrylamides such as N, N-dimethylaminopropylacrylamide; N, N-dimethylaminoethyl acrylate, N, N- Aminoalkyl acrylates such as methylaminopropyl acrylate; polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate or ethylene oxide adducts or propylene oxide adducts thereof Polyvalent acrylates; acrylates such as phenoxy acrylate, bisphenol A diacrylate, and ethylene oxide or propylene oxide adducts of these phenols; glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, Glycidyl ether acrylates such as triglycidyl isocyanurate; and Melamine acrylate, hydroxypivalic acid neopentyl glycol ester diacrylate and the methacrylates corresponding to the acrylates.

  In the present invention, at least one of the components (C) is preferably a monofunctional (meth) acrylate monomer because a cured product having excellent low warpage can be obtained. Moreover, it is preferable that at least 1 type among (C) component is a trifunctional or more than trifunctional (meth) acrylate monomer from a sclerosing | hardenable viewpoint.

  Moreover, the (meth) acrylate monomer which has a phosphate ester structure can be contained as at least 1 sort (s) among (C) components. In the case of containing a (meth) acrylate monomer having a phosphate ester structure, the cured product is excellent in adhesion, which is preferable. Among these, liquid materials that are easy to handle at room temperature are preferable.

  The amount of component (C) is the total amount of photoreactive monomers corresponding to component (C), and is preferably 1 to 50 parts by weight, more preferably 5 parts per 100 parts by weight of photocurable resin (A). It is contained at a ratio of ˜30 parts by mass.

[(D) Colorant]
The photocurable composition of the present invention can contain a colorant. A colorant, such as a black colorant, can reduce the curability of the photocurable composition because it absorbs light. However, according to this invention, even if it contains such a coloring agent, the photocurable composition excellent in sclerosis | hardenability can be obtained. As the colorant, conventionally known colorants such as black, red, blue, green, yellow, and white can be used, and any of pigments, dyes, and pigments may be used. Specific examples include color index (CI; issued by The Society of Dyer's and Colorists) number. However, it is preferable that the colorant does not contain a halogen from the viewpoint of reducing environmental burden and affecting the human body.

  (D) A coloring agent may be used individually by 1 type, and may be used in combination of 2 or more type. (D) The colorant is preferably 0.01 to 1 part by weight, more preferably 0.05 to 0.5 part by weight, and still more preferably 0.08 to 100 parts by weight of the (A) photocurable resin. It is contained at a ratio of ~ 0.3 parts by mass. When the colorant is 0.01 parts by mass or more, a clear color tone is easily obtained. On the other hand, when the colorant is 1 part by mass or less, it is difficult for the colorant to block ultraviolet rays and to inhibit the photoradical polymerization reaction.

[Other ingredients]
As long as the effects of the present invention are not impaired, known additives other than the above components may be blended in the photocurable composition of the present invention. Additives include thermal polymerization inhibitors, UV absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, anti-aging agents, antibacterial / antifungal agents, antifoaming agents, leveling agents, fillers, thickeners , Adhesion imparting agent, thixotropic property imparting agent and the like. Further, as will be described later, in the case where the photocurable composition of the present invention is cured while being filled in the recesses, it is often not necessary to go through a drying step. Said that it is preferable not to mix | blend does not exclude that a trace amount applicable component is contained in a composition.

[Method of curing the composition to make a molded product]
The photocurable composition according to the present invention is cured by irradiating ultraviolet rays, preferably ultraviolet rays having a wavelength of 200 to 400 nm, after coating on a substrate or the like by the following coating method.

  Examples of the ultraviolet light source include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp or a metal halide lamp, a laser, and a UV-LED.

  As a coating method, any method such as a dip coating method, a flow coating method, a roll coating method, a bar coater method, a screen printing method, a curtain coating method, a gravure printing method, and an offset printing method can be applied.

  Here, by using a plate having a recess on the surface, filling the photocurable composition of the present invention into the recess, curing the filled photocurable composition with ultraviolet rays, and taking the cured product out of the recess A method for obtaining a molded product will be exemplified with reference to the drawings.

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

  FIG. 2 shows a state (3) in which the plate is filled with the photocurable composition of the present invention. In general, the photocurable composition is filled into the concave portion of the plate using a doctor knife or the like.

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

  FIG. 4 shows a state in which the cured product is released from the plate body (1) to obtain a cured molded body (6). In the series of steps shown in FIGS. 1 to 4, a molded product can be continuously produced by using a dedicated apparatus.

  The photocurable composition of the present invention has a viscosity at 25 ° C. of preferably 1 to 80 dPa · s, more preferably 10 to 50 dPa · s. With such a viscosity range, the balance between curability and warpage is excellent.

  The molded article of the present invention is formed by molding the photocurable composition of the present invention. In the molding method by photocuring while filling the concave portion, since there is no inhibition of curing by oxygen, the thickness can be increased, and the thickness can be 5 mm at the thickest portion.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not restrict | limited at all by these Examples and a comparative example.

  The components described in Tables 1 and 2 below were mixed and stirred to prepare a photocurable composition.

(Moldability)
About each obtained composition, the viscosity in 25 degreeC was measured with the Toki Sangyo Co., Ltd. cone plate type viscometer TVE-33H (corn rotor 3 degrees R9.7, 5 rpm). A low-viscosity photocurable composition is excellent in moldability because it has good handleability when, for example, filling the concave portion of a molding plate.

(Test specimen preparation conditions for warpage and pencil hardness evaluation)
Each transparent photocurable composition was coated on a readily adhesive PET film manufactured by Toyobo Co., Ltd. with a bar coater so that the film thickness after curing was about 70 μm, and further covered with an untreated PET film from above, and a UV conveyor furnace ( A high-pressure mercury lamp, 80 W, 3 lamps) were used for exposure at an exposure amount of 2000 mJ / cm ² , the untreated PET film was peeled off, and further heated at 120 ° C. for 1 hour in a hot air circulating drying furnace to obtain a test piece.

(Low warpage)
Cut the obtained test piece into a 5cm square, place it on a flat base so that the warped side faces upward, and press the side with the warp against the base with your finger. The height of the was read and the warpage was measured.
◎: Warpage amount of the test piece is less than 3 mm ○: Warpage amount of the test piece is 3 mm or more and less than 5 mm △: Warpage amount of the test piece is 5 mm or more and less than 10 mm

(Curable)
A pencil of B to 9H sharpened so that the tip of the core was flattened was pressed against each test piece at an angle of about 45 °, and the hardness of the pencil at which no peeling of the coating film occurred was recorded.

※１：ダイセル・サイテック社製ＥＢＥＣＲＹＬ８４０２、２官能ウレタンアクリレート、光硬化性樹脂
※２：ダイセル・サイテック社製ＥＢＥＣＲＹＬ８６０、２官能ポリエステルアクリレート、光硬化性樹脂
※３：ダイセル・サイテック社製ＥＢＥＣＲＹＬ１８７０、６官能ポリエステルアクリレート、光硬化性樹脂
※４：ＩＨＴ社製Ｏｍｎｉｐｏｌ９２１０、ＰＰＴＴＡで希釈したポリエチレングリコール（２００）ジ（β−４−［４−（２−ジメチルアミノ−２−ベンジル）ブタノイルフェニル］ピペラジン）プロピオネート、紫外線吸収団を２つ有する液状光重合開始剤（上記化合物Ｎｏ．６）
※５：ＩＨＴ社製Ｏｍｎｉｐｏｌ９２２０、５０％ＴＭＰ３ＥＯＴＡ（エトキシ化（３）トリメチロールプロパントリアクリレート）で希釈したポリエチレングリコール（２００）ジ（β−４−［４−（２−ジメチルアミノ−２−ベンジル）ブタノイルフェニル］ピペラジン）プロピオネート、紫外線吸収団を２つ有する液状光重合開始剤（上記化合物Ｎｏ．６）
※６：ＢＡＳＦジャパン社製イルガキュア１８４、１−ヒドロキシ−シクロヘキシル−フェニルケトン、紫外線吸収団を１つ有する固形光重合開始剤
※７：ＢＡＳＦジャパン社製ダロキュア１１７３、２−ヒドロキシ−２−メチル−１−フェニル-プロパン−１−オン、紫外線吸収団を１つ有する液状光重合開始剤
※８：三菱レイヨン社製ダイヤビームＵＫ−４１０１、ヒドロキシピバリン酸ネオペンチルグリコールエステルジアクリレート、２官能光反応性モノマー
※９：新中村化学工業社製ＮＫエステルＡ−ＮＰＧ、ネオペンチルグリコールジアクリレート、２官能光反応性モノマー
※１０：共栄社化学社製ライトエステルＨＯ−２５０（Ｎ）、２−ヒドロキシメチルメタクリレート、１官能光反応性モノマー
※１１：日本化薬社製カヤラッドＴＭＰＴＡ、トリメチロールプロパントリアクリレート、３官能光反応性モノマー
※１２：日本化薬社製カヤラッドＤＰＨＡ、ジペンタエリスリトールヘキサアクリレート、６官能光反応性モノマー
※１３：石原産業社製タイペークＣＲ−９７、着色剤

* 1: EBECRYL8402, bifunctional urethane acrylate, photocurable resin by Daicel-Cytec Co., Ltd. * 2: EBECRYL860, bifunctional polyester acrylate, photocurable resin by Daicel-Cytec Co., Ltd. * 3: EBECRYL1870, hexafunctional by Daicel-Cytec Polyester acrylate, photocurable resin * 4: Omnipol 9210 manufactured by IHT, polyethylene glycol (200) di (β-4- [4- (2-dimethylamino-2-benzyl) butanoylphenyl] piperazine) propionate diluted with PPTTA , A liquid photopolymerization initiator having two ultraviolet absorbers (Compound No. 6 above)
* 5: Polyethylene glycol (200) di (β-4- [4- (2-dimethylamino-2-benzyl) diluted with Omnipol 9220, 50% TMP3EOTA (ethoxylated (3) trimethylolpropane triacrylate) manufactured by IHT Butanoylphenyl] piperazine) propionate, a liquid photopolymerization initiator having two ultraviolet absorbers (Compound No. 6 above)
* 6: BASF Japan Irgacure 184, 1-hydroxy-cyclohexyl-phenyl ketone, solid photopolymerization initiator having one UV absorber * 7: BASF Japan Darocur 1173, 2-hydroxy-2-methyl-1 -Phenyl-propan-1-one, liquid photopolymerization initiator having one UV absorber * 8: Mitsubishi Rayon Diabeam UK-4101, hydroxypivalate neopentyl glycol ester diacrylate, bifunctional photoreactive monomer * 9: NK ester A-NPG, neopentyl glycol diacrylate, Shin-Nakamura Chemical Co., Ltd., bifunctional photoreactive monomer * 10: Light ester HO-250 (N), 2-hydroxymethyl methacrylate, 1 Functional photoreactive monomer * 11: Kayara manufactured by Nippon Kayaku Co., Ltd. TMPTA, trimethylolpropane triacrylate, trifunctional photoreactive monomer * 12: Kayrad DPHA manufactured by Nippon Kayaku Co., Ltd., dipentaerythritol hexaacrylate, hexafunctional photoreactive monomer * 13: Type CR-97 manufactured by Ishihara Sangyo Co., Ltd. , Colorant

  As shown in Tables 3 and 4, Examples 1 to 11 are a photocurable resin, a photopolymerization initiator represented by the general formula (I), and at least two photoreactive monomers having different functional groups. Since it contains, it was excellent in curability. Moreover, Examples 1-10 whose photocurable resin is bifunctional acrylate were excellent also in the low curvature property. Furthermore, since Examples 5-10 are monofunctional (meth) acrylate monomers among at least two types of photoreactive monomers having different numbers of functional groups, in addition to curability and low warpage, moldability It was also excellent. On the other hand, Comparative Examples 1 and 3 contain a photocurable resin and at least two photoreactive monomers having different functional groups, but do not contain the photopolymerization initiator represented by the above general formula (I). Therefore, curability was inferior. Comparative Example 2 contains a photocurable resin and a photopolymerization initiator represented by the general formula (I), but contains a (meth) acrylate monomer other than a monofunctional (meth) acrylate monomer. Therefore, the curability was inferior.

DESCRIPTION OF SYMBOLS 1 ... Plate body 2 ... Concave 3 ... Photocurable composition 4 ... Base material 5 ... Light source 6 ... Molded article

Claims (5)

(A) a photocurable resin,
(B) a photopolymerization initiator represented by the following general formula (I), and
(C) A photocurable composition comprising at least two photoreactive monomers having different numbers of functional groups.

(Wherein, R and R'are each independently a UV absorbing group, _{l 1} is an integer from 2 to 4, _{m 1} is Table integer of 1 or more, the UV absorbing group is represented by the following formula (III) (It is a structure shown by either (V) or (VII) .)

  2. The photocurable composition according to claim 1, wherein at least one of the (C) at least two photoreactive monomers having different functional groups is a monofunctional (meth) acrylate monomer.   Furthermore, (D) a coloring agent is contained, The photocurable composition of Claim 1 or 2 characterized by the above-mentioned.   The photocuring according to any one of claims 1 to 3, wherein the photocuring is used in a molding method that is cured by irradiating active energy rays in a state where the recess is filled, and does not contain an organic solvent. Sex composition. A molded article formed by molding the photocurable composition according to claim 4.

Images