JP6865645B2 - Photocurable resin composition and sheet - Google Patents

Description

The present invention relates to a photocurable resin composition for forming a sheet suitable for three-dimensional molding processing, and a molding sheet using the same.

Acrylic-based photocurable resins are used in many fields to impart special performance to the surfaces of plastic films and plastic moldings. For example, a hard coat film coated on a PET (polyethylene terephthalate) film to impart high hardness is widely used as a touch panel film and a molding film.

Among these, especially for molding, an insert film in which a pattern is printed on the surface of the film and then three-dimensionally molded in a state of being softened by heating is well known, but a hard coat resin layer applied to the film is used. When it is made hard, microcracks are likely to occur on the curved surface when it is processed into a three-dimensional shape, and there are restrictions on the processed shape. Therefore, as a hard coat resin for insert molding that achieves both surface hardness and moldability, for example, a hard coat agent containing a triazine ring-containing (meth) acrylate prepolymer and organic fine particles having an average primary particle size of 80 to 500 nm has been proposed. (Patent Document 1).

By selecting a hard coating agent suitable for such molding applications, restrictions on the machined surface can be eliminated to some extent, but microcracks may still occur in the part where the radius of the curved surface is small, and as a further improvement measure, moldability is improved. An excellent PMMA (polymethylmethacrylate) acrylic resin may be used as a molding sheet. However, in this case, since the acrylic resin is exposed on the surface of the molded product, for example, when it is used for a long period of time for in-vehicle interior use, the part to which cosmetics such as hand cream and sunscreen are attached whitens over time. There was a new problem. Therefore, measures such as applying a chemical resistant layer to the surface layer of the acrylic resin sheet may be taken, but since such measures cause an increase in cost, they have sufficient chemical resistance without coating the surface. There has been a demand for a molded sheet having excellent moldability.

Patent No. 4848200

The invention according to claim 1 has a weight average molecular weight of 1,000 to 10 obtained by reacting (poly) ethylene glycol (a1) with an aliphatic cyclic diisocyanate (a2) and hydroxyl (meth) acrylate (a3). 000 bifunctional urethane and (meth) acrylate oligomer (a), a reactive diluent monomer (B), a photopolymerization initiator and (C) seen contains the (B) is a comprising a methyl methacrylate Provided is a photocurable resin composition applied to a sheet used for molding.

The invention according to claim 2 is a photocurable resin composition applied to a sheet used for molding according to claim 1, wherein the (B) further contains a (meth) acrylate having a polar functional group. provide.

According to a third aspect of the invention, the amount of the (A) is used in the molding according to any one of claims 1 or 2, characterized in that the total solid content of the composition is 35 to 70 wt% Sheet Provided is a photocurable resin composition applied to.

Invention of claim 4, the amount of the (B) is used in the molding according to any one of claims 1 to 3, wherein the the total solid content of the composition is 25 to 60 wt% Sheet Provided is a photocurable resin composition applied to.

The invention according to claim 5 provides a molding sheet obtained by polymerizing and curing a photocurable resin composition applied to the sheet used for molding according to any one of claims 1 to 4.

The invention according to claim 5 provides a molding sheet obtained by polymerizing and curing the photocurable resin composition for a molding sheet according to any one of claims 1 to 4.

The photocurable resin of the present invention is a photocurable resin composition for forming a forming sheet having excellent optical properties and extensibility, and can be applied to decorative applications for vehicle interiors such as electronic devices and automobiles. Therefore, it is useful as a resin composition for a molding sheet having excellent chemical resistance and suitable for three-dimensional molding.

Hereinafter, the present invention will be described in detail.

The composition of the present invention comprises a bifunctional urethane (meth) acrylate-based oligomer (A) having a weight average molecular weight (hereinafter referred to as Mw) of 1,000 to 10,000, a reactive diluting monomer (B), and the like. It is a photopolymerization initiator (C). In addition, in this specification, (meth) acrylate includes both acrylate and methacrylate. Further, the (poly) alkylene glycol includes both alkylene glycol and polyalkylene glycol.

The (A) used in the present invention is a urethane (meth) acrylate obtained by reacting a (poly) alkylene glycol (a1) with an aliphatic cyclic diisocyanate (a2) and a hydroxyl (meth) acrylate (a3). It is a highly reactive oligomer with a highly flexible urethane bond in the molecule. Mw is 1,000 to 10,000, preferably 2,000 to 6,000, and even more preferably 2,500 to 4,000. When Mw is less than 1,000, the molecular weight of the polymerized compound is small, the cohesive force is low, and the curing shrinkage is large. And it is not suitable. The number of functional groups is bifunctional, and when the number of functional groups is trifunctional or higher, the number of cross-linking points increases and the flexibility decreases, resulting in low moldability. Mw was measured and converted into a standard polystyrene-equivalent molecular weight by a gel permeation chromatography method.

Examples of the (poly) alkylene glycol (a1) used in the above (A) include (poly) ethylene glycol, (poly) propylene glycol, (poly) tetramethylene ether glycol, hexaethylene glycol, and 1,3- (poly). There are butylene glycol, 1,4- (poly) butylene glycol and the like, and these may be used alone or in combination of two or more. Among these, (poly) ethylene glycol having many ether bond points and high flexibility is preferable.

Examples of the aliphatic cyclic diisocyanate (a2) used in the above (A) include isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, hydrogenated xylylene diisocyanate, methylcyclohexylene diisocyanate, and 6-norbornane diisocyanate. , These may be used alone or in combination of two or more. Of these, isophorone diisocyanate, which can improve rigidity, is preferable. Aromatic polyisocyanates have very high reaction activity, but are unsuitable because they have low weather resistance and are prone to yellowing.

Examples of the hydroxyl (meth) acrylate (a3) used in the above (A) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl. There are (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 1,4-cyclohexanedimethanol monoacrylate, 4-hydroxycyclohexyl (meth) acrylate, etc., and these are used alone. You may use 2 or more types together. Among these, 2-hydroxypropyl acrylate and 2-hydroxyethyl acrylate are preferable in terms of suppressing crystallization and gelation of the synthesized resin.

As a method for producing a urethane (meth) acrylate-based oligomer, a (poly) alkylene glycol (a1) is reacted with an aliphatic cyclic diisocyanate (a2) under an excessive condition, and a hydroxyl is added to a urethane prepolymer having an isocyanate at the end. In addition to the prepolymer method in which the (meth) acrylate (a3) is reacted, there is a one-shot method in which (a1), (a2) and (a3) are simultaneously added and reacted. The prepolymer method is preferable to the one-shot method because the reaction is easy to control and there are few by-products.

The blending amount of (A) with respect to the total solid content is preferably 35 to 75% by weight, more preferably 40 to 70% by weight. When the amount is 35 parts by weight or more, sufficient cohesive force and film strength can be secured, and when the amount is 75 parts by weight or less, the viscosity of the composition can be appropriately controlled and good workability can be ensured.

The (B) used in the present invention is a main material that dilutes (A) and improves the curing reactivity to form a resin film. For example, there are alkyl-based (meth) acrylates, aromatic (meth) acrylates, and those (meth) acrylates containing polar groups such as hydroxyl groups and amino groups. Specifically, as alkyl-based (meth) acrylates, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, and octyl (meth) acrylate. ) Acrylate, ethylhexyl (meth) acrylate, isononyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, isobornyl acrylate and the like.

Examples of the aromatic (meth) acrylate include phenoxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, methylphenoxyethyl acrylate, phenoxydiethylene glycol acrylate, and phenoxypolyethylene glycol acrylate. Further, as the monomer containing a hydroxyl group, there are 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like, and the amino group is used. Examples of the contained monomer include acrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N-isopropylacrylamide, acrylic loylmorpholin and the like. These monomers may be used alone or in combination of two or more.

The viscosity of (B) is preferably 10,000 mPa · s or less in order to facilitate the adjustment of the viscosity of the formulation, and is preferably monofunctional in order to suppress curing shrinkage and increase the elongation rate. A monomer having a high polarity is preferable from the viewpoint of compatibility with (A), and an acrylate having a small C number and an acrylate having a polar group are exemplified. The SP value as a guideline for polarity is preferably 9 to 12, for example, MMA (methyl methacrylate) is preferable for acrylates having a small number of C, and N, N-diethylacrylamide, acrylic loylmorpholine, etc. having an amino group as a polar group are preferable. Is. If it is used in combination with a highly polar monomer, there is no problem even if a monomer deviating from the SP value of 9 to 12 is used.

The blending amount of (B) with respect to the total solid content is preferably 20 to 60 parts by weight, more preferably 25 to 55 parts by weight. When it is 20% by weight or more, quick curing property can be obtained, and when it is 60% by weight or less, the curing shrinkage rate can be controlled to be small.

The photopolymerization initiator (C) used in the present invention generates radicals by irradiation with ultraviolet rays, electron beams, etc., and the radicals trigger a polymerization reaction, and a general-purpose photopolymerization initiator can be used. Specifically, 2-hirodoxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl -Ketone, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2-hydroxy-2-methyl-1-phenyl-propane-1 -On, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one, etc. may be used alone or in combination of two or more. It is preferable to add 0.5 to 15% by weight with respect to the radically polymerizable component. Examples of commercially available products include Irgacure 127, 184, 369, 651, 500, 819, 907, 2959, 1173, TPO, MBF, OXE01, OXE02, OXE04 (trade name: manufactured by BASF Japan Ltd.).

Furthermore, the photocurable resin composition of the present invention is, if necessary, an antioxidant, an ultraviolet absorber, a (near) infrared absorber, a fluorescent whitening agent, a sensitizer, and a difficulty, as long as the performance is not impaired. Fuels, fillers, organic fine particles, inorganic fine particles, dispersants, silane coupling agents, leveling agents, defoaming agents, surfactants, anti-fingerprint agents, antistatic agents, antibacterial agents, anti-virus agents, anti-polymerization agents, pigments Colorants such as dyes and pigments, and additives such as plasticizers can be used in combination. It can also be diluted with a solvent in order to improve the coating characteristics when forming a sheet.

As a method for forming the photocurable resin composition of the present invention on a molded sheet, for example, if the thickness is about 75 μm, the composition is applied on a release sheet, and after exposure curing, it is wound into a roll as it is. Can be exemplified. As the coating method, known methods such as a bar coater method, an applicator method, a curtain coater method, a roll coater method, a gravure coater method, a reverse coater method, a comma coater method, a lip coater method, and a die coater method can be applied. Further, as a film forming method without a release sheet, known methods such as a solvent casting method and an extrusion molding method (T die method, inflation method) can be applied.

If as the exposure condition at 75μm approximately the thickness of, for ^example, the irradiation intensity of ^{500mW / cm 2 ~3,000mW / cm 2} , 100mJ / cm 2 ~2,000mJ / cm 2 can be exemplified as the cumulative amount of light. As the light source, known light sources such as a high-pressure mercury lamp, a medium-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a xenon lamp, and an LED lamp can be applied.

The thickness of the molded sheet is appropriately determined according to the application, but if it is too thin, the strength is insufficient, and if it is too thick, the moldability is lowered. Therefore, 50 μm to 300 μm is exemplified. There is no problem even if there is. Further, a coating film that imparts other functions may be formed on the surface of the molded sheet using the present photocurable resin composition, or a composite sheet in which other materials are laminated may be formed. Further, when the sheet thickness is 75 μm and the elongation rate at an atmospheric temperature of 130 ° C. is 80% or more, sufficient moldability as a molded sheet for decorative use can be ensured.

Hereinafter, the present invention will be described in detail based on Examples and Comparative Examples, but specific examples are shown and the present invention is not particularly limited thereto. Unless otherwise specified, the measurement was performed under the conditions of room temperature of 25 ° C. and relative humidity of 65%.

Synthetic polyethylene glycol 200 of bifunctional urethane acrylate A (trade name PEG200 solid content 100% manufactured by Toho Chemical Industry Co., Ltd.) and isophorone diisocyanate (trade name manufactured by Sumika Bayer Urethane Co., Ltd. 37.5% of Death Module INCO group) ) 445 parts by weight was added to the MMA monomer, and the mixture was stirred and reacted at 30 ° C. for 30 minutes, and the reaction was terminated when the peak of the isocyanate group was halved by infrared absorption analysis. Next, 130 parts by weight of 2 hydroxypropyl acrylate (trade name: light ester HOP-A solid content 100% manufactured by Kyoeisha Chemical Co., Ltd.) was added, and the mixture was stirred and reacted at 10 ° C. for 30 minutes and then stirred at 60 ° C. for 30 minutes. -The reaction was carried out, and it was confirmed by infrared absorption analysis that the isocyanate group had disappeared, and the MMA ratio was adjusted to 30%, and Mw. 3,200 urethane acrylate A was obtained.

62 parts by weight of synthetic ethylene glycol of bifunctional urethane acrylate B and 445 parts by weight of isophorone diisocyanate (trade name: Death Module INCO group 37.5% manufactured by Sumika Bayer Urethane Co., Ltd.) are added to the MMA monomer and 30 minutes at 30 ° C. The reaction was stirred and reacted, and the reaction was terminated when the peak of the isocyanate group was halved by infrared absorption analysis. Next, 116 parts by weight of 2-hydroxyethyl acrylate (trade name: light ester HOA solid content 100% manufactured by Kyoeisha Chemical Co., Ltd.) was added, and the mixture was stirred and reacted at 10 ° C. for 30 minutes, and then stirred and reacted at 60 ° C. for 30 minutes. After confirming that the isocyanate group had disappeared by infrared absorption analysis, the MMA ratio was adjusted to 30%, and Mw. 3,200 urethane acrylate B was obtained.

Add 200 parts by weight of synthetic polyethylene glycol of hexafunctional urethane acrylate C and 778 parts by weight of isophorone diisocyanate (trade name: Death Module INCO group 37.5% manufactured by Sumika Bayer Urethane Co., Ltd.) to MMA monomer and stir at 30 ° C. for 30 minutes. -The reaction was carried out, and the reaction was terminated when the peak of the isocyanate group reached a predetermined amount in the infrared absorption analysis. Next, 150 parts by weight of pentaerythritol triacrylate (trade name PET30 solid content 100% manufactured by Nippon Kayaku Co., Ltd.) was added, and the mixture was stirred and reacted at 10 ° C. for 30 minutes and then stirred and reacted at 60 ° C. for 30 minutes. After confirming that the isocyanate group had disappeared by infrared absorption analysis, the MMA ratio was adjusted to 40%, and Mw. 4,900 urethane acrylate B was obtained.

Example 1
Urethane acrylate A as (A), MMA as (B), and Irgacure1173 (trade name: manufactured by BASF Japan Ltd.) as (C) are stirred with the formulation shown in Table 1 until they are uniformly dissolved, and the molding of Example 1 is performed. A photocurable resin composition for a sheet was prepared.

Examples 2-8
In addition to the materials used in Example 1, urethane acrylate B was used as (A), and ACMO (trade name: KJ Chemicals Co., Ltd., acryloylmorpholin) and DEAA (trade name: KJ Chemicals Co., Ltd.) were used as (B). Diethylacrylamide) and IBXA (trade name: Kyoeisha Chemical Co., Ltd., isobornyl acrylate) and EC-A (trade name: Kyoeisha Chemical Co., Ltd., ethoxy-diethylene glycol acrylate) are uniformly dissolved in the formulation shown in Table 1. The photocurable resin composition for the molded sheet of Examples 2 to 8 was prepared.

Comparative Examples 1 to 6
In addition to the materials used in the examples, the above C and the following D to F as urethane acrylates were stirred with the formulation shown in Table 1 until they were uniformly dissolved, and the photocurable resin compositions for molded sheets of Comparative Examples 1 to 5 were obtained. Prepared. For comparison, 505 NAH (trade name: manufactured by Kaneka Corporation, thickness 75 μm, acrylic film) was added as Comparative Example 6.
D: Polyol, hexamethylene diisocyanate and 2-hydroxyethyl acrylate were used as raw materials, and Mw. 2,000
E: Caprolactone, hydrogenated diphenylmethane isocyanate and 2-hydroxyethyl acrylate were used as raw materials, Mw. 1,100
F: 1.4 butanediol and isophorone diisocyanate and hexamethylene diisocyanate and 2 hydroxyethyl acrylate were used as raw materials, and Mw. 3,100

Table 1

The evaluation method was as follows.

Appearance: A resin composition having a thickness of 75 μm was irradiated with ultraviolet rays so that the output was 1,000 mW / cm2 and the integrated light intensity was 800 mJ with an electrodeless high-pressure mercury lamp. ◯, 90% or less was marked with x. The total light transmittance was measured using a haze guard manufactured by Toyo Seiki Seisakusho in accordance with JIS K7361-1.

Elongation rate: Measured at a crosshead speed of 300 mm / min and an ambient temperature of 130 ° C. using a Minebea tensile tester TGI-1 kN. The measurement sample was prepared by irradiating a resin composition having a thickness of 75 μm with ultraviolet rays so that the output was 1,000 mW / cm2 and the integrated light amount was 800 mJ with an electrodeless high-pressure mercury lamp, and then cut into 25 mm × 100 mm to prepare the above conditions. The measurement sample was pulled with reference to 50 mm, and the elongation rate at the time of breaking was marked as ◯ for 80% or more and x for less than that. Calculation formula: Elongation rate (%) = Elongation length (mm) / 50mm x 100

Chemical resistance: Neutrogena SPF45 (trade name), which is a hand cream, is applied to a resin composition having a thickness of 75 μm and irradiated with ultraviolet rays so that the output is 1,000 mW / cm2 and the integrated light amount is 800 mJ with an electrodeless high-pressure mercury lamp. : Johnson & Johnson) is applied, left at 80 ° C for 6 hours, returned to room temperature, wiped off, and then the surface condition is observed. It was marked with x.

Evaluation result <br /> Table 2

Good results were obtained for each of the resin compositions of Examples in terms of evaluation items such as appearance, chemical resistance, and elongation.

On the other hand, Comparative Examples 1 and 2 using a hexafunctional urethane acrylate and Comparative Examples 3 to 5 using urethane acrylates having different isocyanates and polyols without (B) have low elongation rates, and none of them is suitable for the present invention. Met. Further, Comparative Example 6 of the acrylic sheet inserted for comparison had low chemical resistance.

The present invention is a photocurable resin composition for forming a molding sheet having excellent optical properties and extensibility, which can be applied to decorative applications for vehicle interiors such as electronic devices and automobiles, and has chemical resistance. It is useful as a molding sheet that is excellent and suitable for three-dimensional molding.

Claims (5)

A bifunctional urethane (meth) having a weight average molecular weight of 1,000 to 10,000 obtained by reacting (poly) ethylene glycol (a1) with an aliphatic cyclic diisocyanate (a2) and hydroxyl (meth) acrylate (a3). acrylate-based oligomer (a), a reactive diluent monomer (B), viewed contains a photopolymerization initiator (C), wherein (B) is applied to the sheet for molding, which comprises methyl methacrylate The photocurable resin composition that. The photocurable resin composition applied to a sheet used for molding according to claim 1, wherein the (B) further contains a (meth) acrylate having a polar functional group. The photocurable resin applied to the sheet used for molding according to any one of claims 1 or 2, wherein the blending amount of (A) is 35 to 70% by weight based on the total solid content of the composition. Composition. The photocurable resin applied to the sheet used for molding according to any one of claims 1 to 3, wherein the blending amount of (B) is 25 to 60% by weight based on the total solid content of the composition. Composition. A molding sheet obtained by polymerizing and curing a photocurable resin composition applied to the sheet used for molding according to any one of claims 1 to 4.