JP2008195754A - Active energy ray-curable resin composition and molded article - Google Patents

Abstract

An active energy ray-curable resin composition for casting polymerization, which prevents curling due to curing shrinkage while maintaining wear resistance and is excellent in adhesion of a cured product to a substrate, transparency and weather resistance. I will provide a.
A urethane poly (meth) acrylate (A), a hydroxyalkyl (meth) acrylate (B) and a photopolymerization initiator (C) obtained by reacting an alicyclic polyisocyanate and a hydroxyalkyl (meth) acrylate. An active energy ray-curable resin composition to be contained; a shaped article obtained by laminating a cured product of the resin composition.
[Selection figure] None

Description

  The present invention is an active energy ray-curable resin composition suitable for cast polymerization suitable for the formation of a cured product that is rapidly cured by irradiation with an active energy ray and has adhesion, transparency, and weather resistance to a substrate. About. More specifically, the present invention relates to an active energy ray-curable resin composition suitable for mold polymerization, which is suitable for cast polymerization to form a hardened product with less deformation and suitable for mold printing.

  The active energy ray-curable resin composition does not require an organic solvent, and can give excellent properties such as toughness, flexibility, scratch resistance, weather resistance, and chemical resistance to the cured product according to the composition. Furthermore, since the active energy ray-curable resin composition has a property of being cured in a short time by active energy rays and is generally excellent in transparency, it is particularly applied to optical applications.

  In recent years, in electronic devices such as mobile phones, in particular, a component in which a resin cured product having a fine and complicated uneven surface shape such as a button or a logo mark is formed on a plate-like or sheet-like transparent plastic substrate is used. Sometimes.

  Patent Document 1 discloses an active energy ray-curable resin composition for cast polymerization containing an epoxy (meth) acrylate having a cured product with excellent transparency and shape retention as a material for a resin cured product for the above-mentioned use. Proposed.

However, the resin composition described in Patent Document 1 discloses an epoxy (meth) acrylate having an aromatic ring, but has a problem that it tends to yellow after a weather resistance test. In order to obtain a harder resin composition without using a (meth) acryloyl group-containing compound having an aromatic ring that causes yellowing, it is represented by trimethylolpropane triacrylate and dipentaerythritol hexaacrylate. A technique using a polyfunctional (meth) acryloyl group-containing compound is common. However, in this method, there is a problem that curling of the shaped article on which the cured product is formed increases due to curing shrinkage due to active energy ray curing.
JP 2003-342334 A

  The object of the present invention is to prevent casting curling due to curing shrinkage while maintaining wear resistance, and for casting polymerization having excellent adhesion to the substrate, transparency and weather resistance of the cured product. It is to provide an energy ray curable resin composition.

  The present invention relates to urethane poly (meth) acrylate (A), hydroxyalkyl (meth) acrylate (B) and photopolymerization initiator (C) obtained by reacting alicyclic polyisocyanate and hydroxyalkyl (meth) acrylate. An active energy ray-curable resin composition to be contained.

In the present invention, the urethane poly (meth) acrylate (A) is preferably a compound represented by the following formula (1).

(In the formula, R ¹ represents an alicyclic diisocyanate residue, R ² represents an alkylene group, and R ³ represents a hydrogen atom or a methyl group.)
Moreover, this invention is a molded article which laminated | stacked the hardened | cured material of the above-mentioned active energy ray hardening-type resin composition on the base material.

  The active energy ray-curable resin composition (hereinafter referred to as “the present resin composition”) suitable for cast polymerization according to the present invention is rapidly cured by irradiation with active energy rays, and the resulting cured product is wear-resistant. Because of its excellent properties, transparency, weather resistance, and RCA resistance, it is very suitable for molding materials by casting polymerization with active energy rays, especially casting molding by mold printing on plastic film substrates. Yes.

Urethane poly (meth) acrylate (A)
The urethane poly (meth) acrylate (A) constituting the resin composition is obtained by reacting an alicyclic polyisocyanate and a hydroxyalkyl (meth) acrylate, and imparts low shrinkage to the resin composition. It is a component that improves the flexibility of the cured product layer.

Alicyclic polyisocyanate Examples of the alicyclic polyisocyanate include alicyclic polyisocyanate compounds having two or more isocyanate groups in the molecule.

  Specific examples of the alicyclic polyisocyanate compound include isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane and 1,4-cyclohexyl diisocyanate. Furthermore, a polyisocyanate compound obtained by reacting these alicyclic polyisocyanate compounds with a compound having at least two active hydrogen atoms such as amino group, hydroxyl group, carboxyl group, water, or the above alicyclic polyisocyanate Trimers to pentamers of compounds can also be used.

Hydroxyalkyl (meth) acrylate Examples of the hydroxyalkyl (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) ) Hydroxyl group-containing alkyl (meth) acrylates such as acrylate and 6-hydroxyhexyl acrylate; addition reaction products of monoepoxy compounds such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether and glycidyl (meth) acrylate with (meth) acrylic acid Is mentioned.

  Among these, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) in terms of low viscosity of the synthesized urethane poly (meth) acrylate (A). Acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl acrylate are preferred.

  Among the urethane poly (meth) acrylate (A) constituting the resin composition, a compound represented by the formula (1) obtained by reacting an alicyclic diisocyanate and a monohydroxyalkyl (meth) acrylate is preferable. A molded product obtained by laminating a cured product of a resin composition containing the compound is further excellent in deformation relaxation properties.

  In this resin composition, the compounding amount of the urethane poly (meth) acrylate (A) is 40 to 90 mass in a total of 100 mass parts of the urethane poly (meth) acrylate (A) and the hydroxyalkyl (meth) acrylate (B). Part is preferred. When the urethane poly (meth) acrylate (A) is 40 parts by mass or more, there is a tendency that sufficient hardness can be imparted to the cured product, and when it is 90 parts by mass or less, the viscosity of the resin composition becomes moderate, and cast polymerization. There is a tendency to improve workability. A more preferable blending amount of the urethane poly (meth) acrylate (A) is 60 to 80 parts by mass.

  As a method for producing the urethane poly (meth) acrylate (A), for example, the alicyclic polyisocyanate compound and the hydroxyalkyl (meth) acrylate are used with respect to 1 equivalent of the isocyanate group of the alicyclic polyisocyanate compound. Examples of the method include an addition reaction at a ratio of about 1 to 1.1 equivalents of hydroxyl group of hydroxyalkyl (meth) acrylate.

  The addition reaction between the alicyclic polyisocyanate compound and hydroxyalkyl (meth) acrylate can be carried out by a known method. For example, a mixture of a hydroxyalkyl (meth) acrylate or an alicyclic polyisocyanate compound and a catalyst such as di-n-butyric acid laurate in an alicyclic polyisocyanate compound or a hydroxyalkyl (meth) acrylate at 50 to 90 ° C. After dripping under the conditions, urethane poly (meth) acrylate (A) can be produced by further reacting for 6 to 12 hours.

Hydroxyalkyl (meth) acrylate (B)
Examples of the hydroxyalkyl (meth) acrylate (B) used in the present invention include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl ( Hydroxyl group-containing alkyl (meth) acrylates such as meth) acrylate and 6-hydroxyhexyl acrylate; addition reaction of monoepoxy compounds such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether and glycidyl (meth) acrylate with (meth) acrylic acid Things.

  Among these, in order to reduce the viscosity of the resulting composition and to improve the adhesion of the cured product to the substrate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, Hydroxyl group-containing alkyl (meth) acrylates such as 2-hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferred.

  As for the compounding quantity of a hydroxyalkyl (meth) acrylate (B), 10-60 mass parts is preferable in a total of 100 mass parts of urethane poly (meth) acrylate (A) and hydroxyalkyl (meth) acrylate (B). When the compounding amount of the hydroxyalkyl (meth) acrylate (B) is 10 parts by mass or more, the viscosity of the resin composition becomes appropriate, and the workability of the casting polymerization tends to be improved. Moreover, when this resin cured material is apply | coated and hardened on a base material with a hydroxyalkyl (meth) acrylate (B) being 60 mass parts or less, the curvature of a base material can be decreased, and it is enough for hardened | cured material. There is a tendency that a high hardness can be imparted.

  A more preferable blending amount of the hydroxyalkyl (meth) acrylate (B) is 20 to 40 parts by mass.

Photopolymerization initiator (C)
This resin composition contains a photopolymerization initiator (C) in order to efficiently obtain a cured product by irradiation with active energy rays.

  Examples of the photopolymerization initiator (C) include those that generate radical sources mainly in response to ultraviolet rays having a wavelength of 200 to 400 nm.

  Specific examples of the photopolymerization initiator (C) include benzoin, benzoin monomethyl ether, benzoin isopropyl ether, acetoin, benzyl, benzophenone, p-methoxybenzophenone, diethoxyacetophenone, benzyldimethyl ketal, 2,2-diethoxyacetophenone, Carbonyl compounds such as 1-hydroxycyclohexyl phenyl ketone, methylphenylglyoxylate, ethylphenylglyoxylate, 2-hydroxy-2-methyl-1-phenylpropan-1-one; tetramethylthiuram monosulfide, Sulfur compounds such as tetramethylthiuram disulfide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpenti Acylphosphine oxides such as phosphine oxide. These can be used alone or in combination of two or more.

  Of these, benzophenone, benzoin isopropyl ether, methylphenyl glyoxylate, 1-hydroxycyclohexyl phenyl ketone, benzyldimethyl ketal, and 2,4 in terms of the balance between the hardness and curlability of the cured product. , 6-Trimethylbenzoyldiphenylphosphine oxide is preferred.

  The compounding quantity of a photoinitiator (C) is 0.005-5 mass parts with respect to a total of 100 mass parts of urethane poly (meth) acrylate (A) and hydroxyalkyl (meth) acrylate (B). preferable. When the photopolymerization initiator (C) is 0.005 parts by mass or more, curing tends to be sufficient, and when it is 5 parts by mass or less, transparency and toughness of the cured product tend to be secured. A more preferable blending amount of the photopolymerization initiator (C) is 0.1 to 1.5 parts by mass.

In the present invention, in the present invention, a urethane (meth) acrylate other than the urethane poly (meth) acrylate (A), a polyfunctional oligomer, a polyfunctional monomer, and the like, as long as the effects of the present resin composition are not disturbed. A monomer, a monofunctional monomer other than hydroxyalkyl (meth) acrylate (B), a polymer, and the like can be blended. As urethane (meth) acrylates other than urethane poly (meth) acrylate (A), urethane (meth) acrylate synthesized from non-alicyclic polyisocyanate and hydroxyalkyl (meth) acrylate; alicyclic or non-alicyclic And urethane (meth) acrylate synthesized from polyisocyanate of formula, polyol and hydroxyalkyl (meth) acrylate. In the total amount of urethane (meth) acrylate, the urethane methacrylate (A) is preferably 50% by mass or more.

  In addition, the resin composition may contain an antioxidant, an anti-yellowing agent, an ultraviolet absorber, a bluing agent, a pigment, an anti-settling agent, an antifoaming agent, an antistatic agent, an antifogging agent, etc. Various additives can be blended.

Base material As a base material used in order to shape the hardened | cured material of this resin composition, an acrylic resin type, a polycarbonate type, and a vinyl chloride type film-form thing are mentioned, for example. In particular, when a cured product of the present resin composition is formed on a base material, it is preferable to use a base material that has been previously subjected to an easy adhesion treatment.

Cured product of the present resin composition The cured product of the present resin composition is excellent in abrasion resistance, transparency, weather resistance and RCA resistance.

Shaped product The shaped product of the present invention is a product obtained by laminating a cured product of the present resin composition on a substrate, obtained by curing the present resin composition on the substrate.

  Examples of the method for obtaining the molded article of the present invention include a casting polymerization method using active energy rays and a casting molding method using a mold printing method on a plastic substrate.

  In the present invention, casting molding by the mold printing method means that the intaglio plate into which the active energy ray-curable resin composition is poured is sealed with a transparent plastic film base material, and the active energy ray is cured by irradiating the active energy rays. It means that the mold resin composition is cured and formed into a convex shape on the substrate.

  For example, a mold corresponding to the application is overlaid on a base material such as a plastic film that has been subjected to an easy adhesion treatment in advance via the resin composition. Next, the resin composition is cured by irradiating active energy rays from the substrate side using a high-pressure mercury lamp, metal halide lamp, halogen lamp or the like. Thereafter, the laminate of the cured product of the base material and the resin composition is released from the mold, whereby a product in which the convex cured product is shaped on the target base material can be obtained.

  Hereinafter, the present invention will be described using examples. Hereinafter, “part” means part by mass.

[Synthesis Example 1] (Production of urethane diacrylate (A1))
In a 5-liter four-necked flask, 2,500 parts of 2-hydroxypropyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: 2-HPA), SCAT-24 (butyltin compound, three-share machine synthesis (stock) )) 0.2 parts and hydroquinone monomethyl ether (manufactured by Kawaguchi Chemical Industry Co., Ltd., trade name; MQ) 2.2 parts. The mixture was brought to 65 ° C., and 2,000 parts of isophorone diisocyanate (manufactured by Sumitomo Bayer Co., Ltd., trade name: Desmodur I) was added dropwise over 6 hours while stirring. After completion of the dropwise addition, the reaction was further continued at 75 ° C. for 2 hours. As urethane poly (meth) acrylate (A), R ¹ in formula (1) was an isophorone diisocyanate residue, R ² was an isopropylene group, and R ³ was Urethane diacrylate (A1) which is a hydrogen atom was obtained.

[Synthesis Example 2] (Production of Urethane Diacrylate (A2))
Instead of 2,000 parts of isophorone diisocyanate, 1,750 parts of 1,3-bis (isocyanatomethyl) cyclohexane (manufactured by Takeda Pharmaceutical Co., Ltd., trade name: Takenate-600) was used instead of SCAT-24. 0.8 parts of di-n-butyltin laurate and 2.1 parts of hydroquinone monomethyl ether were used. Otherwise, as in Synthesis Example 1, as urethane poly (meth) acrylate (A), R ¹ in formula (1) is a 1,3-bis (isocyanatomethyl) cyclohexane residue, and R ² is an isopropylene group Urethane diacrylate (A2) in which R ³ is a hydrogen atom was obtained.

[Synthesis Example 3] (Production of urethane diacrylate (A3))
Instead of 2,500 parts of 2-hydroxypropyl acrylate, 2,200 parts of 2-hydroxyethyl acrylate were used, and the amount of hydroquinone monomethyl ether used was 2.1 parts. Otherwise, as in Synthesis Example 1, urethane di (meth) acrylate (A) is a urethane di (R) in formula (1) where R ¹ is an isophorone diisocyanate residue, R ² is an ethylene group, and R ³ is a hydrogen atom. An acrylate (A3) was obtained.

[Synthesis Example 4] (Production of urethane diacrylate (A4))
Use 2,700 parts of 4-hydroxybutyl acrylate instead of 2,500 parts of 2-hydroxypropyl acrylate, 0.7 parts of di-n-butyltin laurate instead of SCAT-24, and hydroquinone monomethyl ether The amount used was 2.4 parts. Otherwise, in the same manner as in Synthesis Example 1, as urethane poly (meth) acrylate (A), R ¹ in formula (1) is an isophorone diisocyanate residue, R ² is a normal butylene group, and R ³ is a hydrogen atom. Diacrylate (A4) was obtained.

[Synthesis Example 5] (Production of urethane diacrylate (X1))
In a 5-liter four-necked flask, 1,750 parts of 1,3-bis (isocyanatomethyl) cyclohexane and 1.6 parts of di-n-butyltin laurate were placed. The temperature was set to 40 ° C., and 2,100 parts of polycaprolactone diol (manufactured by Daicel Chemical Industries, Ltd., trade name: Plaxel 205) was added dropwise over 4 hours while stirring. After completion of the dropwise addition, the reaction was further continued at 50 ° C. for 2 hours. Thereafter, the resulting reaction solution was brought to 65 ° C., and a mixture of 1,300 parts of 2-hydroxypropyl acrylate and 2.6 parts of hydroquinone monomethyl ether was added dropwise over 2 hours while stirring. After completion of the dropwise addition, the reaction was further continued at 70 ° C. for 2 hours to obtain urethane diacrylate (X1).

[Synthesis Example 6] (Production of epoxy acrylate)
Bisphenol A type epoxy resin (Asahi Denka Kogyo Co., Ltd., trade name; Adeka Resin EP-4100) 3,600 parts, acrylic acid 1,300 parts, triethylammonium chloride (Nippon Yushi Co., Ltd.) ), Trade name: TEMA-Cl) 42 parts and 7.2 parts of hydroquinone monomethyl ether were added. The mixture was heated to 70 ° C. over 1 hour and then held for 1 hour, heated to 80 ° C. for 0.5 hour, then held for 1 hour, heated to 90 ° C. for 0.5 hour and then held for 1 hour, After raising the temperature to 95 degrees in 0.5 hours, the temperature was maintained for 6 hours to obtain an epoxy acrylate.

[Example 1]
(1) Preparation of resin composition 80 parts of urethane diacrylate (A1) as urethane poly (meth) acrylate (A), 4-hydroxybutyl acrylate as hydroxyalkyl (meth) acrylate (B) (Osaka Organic Chemical Co., Ltd.) Product name: 4-HBA) 20 parts, 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals Co., Ltd., trade name: Irgacure 184) 1 part and 2,4, as photopolymerization initiator (C) 0.025 part of 6-trimethylbenzoyldiphenylphosphine oxide (manufactured by BASF, trade name: Lucillin TPO) was mixed and stirred at room temperature to obtain a resin composition.

(2) Production of mold A double-sided adhesive tape (product number: TRT-25, manufactured by Trusco Nakayama Co., Ltd.) having a width of 20 mm and a thickness of 25 μm is formed on four sides of a glass plate having a length of 120 mm, a width of 120 mm and a thickness of 1.8 mm. Laminate an iron plate with a width of 25 mm and a thickness of 0.5 mm on this double-sided tape (Daisuke Equipment Co., Ltd., drawn steel plate) so that the end surface of the glass plate and the end surface of the iron plate are aligned, and a mold 1 was produced. Further, on the four sides of the same glass plate as described above, two adhesive tapes (manufactured by Nitto Denko Corporation, product number: No. 31B) having a width of 10 mm and a thickness of 25 μm were laminated to prepare a mold 2.

(3) Creation of a shaping | molding film The resin composition prepared previously was inject | poured in each of the casting_mold | templates 1 and 2 obtained above. Next, the injected side is sealed with an easy adhesion treatment side of a polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., trade name: Cosmo Shine A4100, thickness: 188 μm) that has been subjected to easy adhesion treatment, and a high pressure mercury lamp Was irradiated with ultraviolet rays having an illuminance of 90 mW / cm ² and a light amount of 1,000 mJ / cm ² from the film surface side to cure the resin composition. The cured product is removed from the mold, and two types of molded films are obtained, each of which has a thickness of 0.525 mm and 50 μm laminated on the surface of the film, and the physical properties of these molded films are evaluated. did.

(4) Physical property evaluation <E-type viscosity>
E-type viscosity was measured in accordance with JIS-Z8803 using a Viscometer TV-20 (trade name) manufactured by Toki Sangyo Co., Ltd.

<Warpage>
A 35 mm square piece was cut out from the shaped film obtained using the mold 1. The height of the rising of the angle A from the horizontal base when the diagonal B of the most lifted angle A was pressed from above onto the horizontal base was measured, and the level of warpage was judged.

<RCA test>
The cured product on the shaped film obtained using the mold 2 was worn under the conditions of a load of 175 g and 80 cycle wear using an RCA abrasion tester manufactured by The Norman Tool & Stamping Company. The case where the surface of the PET film was not exposed after the abrasion treatment was “◯”, and the exposed state was “X”.

<Transmissivity>
The light transmittance (%) of the shaped film obtained using the mold 1 was measured. For the measurement of transmittance, Haze Meter HM-65W (trade name) manufactured by Murakami Color Research Laboratory Co., Ltd. was used.

<Adhesion>
The cured product on the shaped film obtained using the mold 2 was cut into a 1 cm × 1 cm portion that reached the PET film with a cutter at 1 mm vertical and horizontal intervals, and an adhesive tape (manufactured by Nitto Denko Corporation, product number; No. 31B) was used to perform a peelability test. After peeling off the adhesive tape, the number of squares (in 100 squares) where the coating film remained on the substrate was measured to evaluate the adhesion. The peeling angle when peeling the adhesive tape was 90 degrees.

<Color difference after weathering test>
The shaped film obtained using the mold 1 was subjected to a weather resistance test using a sunshine weather meter for 150 hours (conditions: UV irradiation for 48 minutes, UV irradiation for 12 minutes and rainfall), and the color difference ΔE before and after that was measured. It measured according to JIS-Z8730.

  The various evaluation results are shown in Table 1.

[Examples 2-7 and Comparative Examples 1-3]
A shaped film was obtained in the same manner as in Example 1 except that the resin composition shown in Table 1 was used. Various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

Abbreviations in Table 1 are as follows.

UA1: Urethane diacrylate (A1)
UA2: Urethane diacrylate (A2)
UA3: urethane diacrylate (A3)
UA4: Urethane diacrylate (A4)
UA5: urethane diacrylate (X1)
EA1: Epoxy acrylate 2-HEA obtained in Synthesis Example 6: 2-hydroxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: 2-HEA)
2-HPA: 2-hydroxypropyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: 2-HPA)
4-HBA: 4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: 4-HBA)
POA: Phenoxyethyl acrylate (Daiichi Kogyo Seiyaku Co., Ltd., trade name: New Frontier PHE)
Irg. 184: 1-Hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals Co., Ltd., trade name; Irgacure 184)
APO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (manufactured by BASF, trade name: Lucillin TPO)

Claims (3)

  Active energy containing urethane poly (meth) acrylate (A), hydroxyalkyl (meth) acrylate (B) and photoinitiator (C) obtained by reacting alicyclic polyisocyanate and hydroxyalkyl (meth) acrylate A linear curable resin composition. The active energy ray-curable resin composition according to claim 1, wherein the urethane poly (meth) acrylate (A) is a compound represented by the following formula (1).

(In the formula, R ¹ represents an alicyclic diisocyanate residue, R ² represents an alkylene group, and R ³ represents a hydrogen atom or a methyl group.)   A molded article obtained by laminating a cured product of the active energy ray-curable resin composition according to claim 1 or 2 on a substrate.