JP4771110B2 - Protective layer forming sheet and protective layer forming method - Google Patents

Description

  The present invention provides a molded article having a protective layer excellent in abrasion resistance and chemical resistance, and has a B-staged cured coating film that is not sticky and can be easily stored. The present invention also relates to a method for forming a protective layer of a molded article using the protective layer forming sheet.

  As a method for forming the protective layer on the surface of the molded product, for example, there is a sheet bonding method. The sheet bonding method is a method of forming a protective layer on the surface of a molded product by adhering a protective sheet having a protective layer and, if necessary, a decorative layer on a base sheet to a plastic molded product. In this sheet bonding method, a method of directly bonding a protective sheet to a molded product such as a plastic molded product, and a method of adhering a protective sheet to the inner surface of a mold when plastic is molded in-mold, and bonding at the same time as molding Etc. The protective sheet used in the sheet bonding method is required to have a protective layer excellent in scratch resistance and solvent resistance, and to be able to stably store the protective sheet in, for example, a roll state. On the other hand, for example, a photocurable resin composition comprising an acrylic resin (a-1) having a photopolymerizable functional group in the side chain, a photopolymerization initiator (a-2), and an acrylic rubber-like elastic body (a-3). A photocurable sheet obtained by applying a product (A) onto a base sheet (B) and then dried by a hot air dryer or the like is known, and a protective layer is formed on a molded product using this photocurable sheet. In order to form the photocurable resin composition (A) on the photocurable sheet, for example, by adhering the substrate sheet surface of the photocurable sheet and the surface of the molded product and then irradiating with ultraviolet rays. Is known to form a protective layer by curing (E.g., see Patent Document 1.).

  However, since the photocurable resin composition (A) on the photocurable sheet of Patent Document 1 is in a dried state and is not crosslinked and cured by ultraviolet irradiation, the photocurable resin composition (A ) Will become sticky over time. Therefore, when this photocurable sheet is stored in a roll or the like, the photocurable resin composition (A) and the base material sheet are in close contact with each other, and there is a problem that the sheet cannot be rewound during use.

JP 11-314324 A

  An object of the present invention is to obtain a molded article having a protective layer excellent in scratch resistance and solvent resistance, and for forming a protective layer having a B-staged cured coating film having no adhesiveness and good storage stability. An object of the present invention is to provide a method for forming a protective layer of a molded product using the sheet and the protective layer forming sheet.

Thus, as a result of intensive investigations aimed at the problems described above, the present inventors have found the following findings (1) to (3) and have completed the present invention.
(1) A curable resin composition containing a compound (A) having a cyclic ether structure, a compound (B) having a (meth) acryloyl group, and a thermal cationic polymerization initiator (C) is irradiated with active energy rays. By this, the (meth) acryloyl group (α-β unsaturated carbonyl group) in the curable resin composition starts a radical polymerization reaction and is semi-cured (B-staged), and further B-staged curable resin. The composition is completely cured by heating by the cationic polymerization reaction of the cyclic ether in the compound (A). This completely cured curable resin composition is excellent in scratch resistance and solvent resistance.
(2) After coating the curable resin composition on a base sheet, a protective layer forming sheet having a B-staged resin layer can be produced by irradiating active energy rays. The staged resin layer is not sticky even when touched with a finger (no residual tack), and no increase in stickiness over time is observed. Therefore, this protective layer forming sheet can be stably stored in a roll state or the like.
(3) A molded product having a protective layer excellent in scratch resistance and solvent resistance can be obtained by heating after bonding the protective layer forming sheet and a substrate such as a molded product, and the protective layer. Even when the forming sheet is bonded, the protective layer does not crack in the curved surface portion of the molded product.

That is, in the present invention, a curable resin composition containing a compound (A) having a cyclic ether structure, a compound (B) having a (meth) acryloyl group and a thermal cationic polymerization initiator (C) is coated on a base sheet. after a coercive Mamoruso formation sheet that having a by irradiating an active energy ray coating layer formed by B- staged the curable resin composition, a compound having a cyclic ether structure (a) is 3, It is an alicyclic epoxy (meth) acrylic resin having a weight average molecular weight of 500 to 50,000 obtained by polymerizing 4-epoxycyclohexylmethyl (meth) acrylate as an essential component, and the compound (B) having a (meth) acryloyl group Weight average molecular weight 20 obtained by reacting an epoxy resin obtained by polymerizing glycidyl (meth) acrylate as an essential component with (meth) acrylic acid The number of moles of the (meth) acryloyl group in the compound (B) relative to the number of moles (a) of the cyclic ether structure in the compound (A) (b) [b] (B) / (a)] is 1 to 10 to provide a protective layer forming sheet.

  Further, the present invention provides the protection of a molded product characterized in that after the base sheet of the protective layer forming sheet and the molded product are bonded, the coating layer formed by the B-stage is further cured by heating. A method for forming a layer is provided.

  The protective layer forming sheet of the present invention is excellent in scratch resistance and solvent resistance, and also has good storage stability. According to the method for forming a protective layer of a molded product of the present invention, a protective layer having excellent scratch resistance and solvent resistance can be easily applied on the molded product, and cracks are generated in the protective layer when the protective layer is formed. Absent. Furthermore, the molded article which is excellent in an external appearance and designability can be manufactured by using the sheet | seat for protective layer formation.

The present invention is described in detail below. The compound (A) used in the present invention is an alicyclic epoxy (meth) acrylic resin having a weight average molecular weight of 500 to 50,000 obtained by polymerizing 3,4-epoxycyclohexylmethyl (meth) acrylate as an essential component .

The compound (A) having a cyclic ether structure of the present invention can be obtained by polymerizing 3,4-epoxycyclohexylmethyl (meth) acrylate with other acrylic monomers and non-acrylic monomers as necessary.

Examples of the (meth) acrylic monomer having a cyclic ether structure other than 3,4-epoxycyclohexylmethyl (meth) acrylate include (meth) acrylic monomers having an epoxy group, (meth) acrylic monomers having an oxetane group, and the like. It is done.

The (meth) acrylic monomer having an epoxy group include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether, 2- (1,2-epoxy-4,7-methanolate perhydro indene -5 (6) -yl) oxyethyl (meth) acrylate, 5,6-epoxy-4,7-methanoperhydroinden-2-yl- (meth) acrylate, 1,2-epoxy-4,7-methanopel (Meth) acrylic monomers having a glycidyl ether type epoxy group such as hydroindene-5-yl- (meth) acrylate; 2,3-epoxycyclopentenyl (meth) acrylate , 3,4-epoxycyclohexylmethylated polycaprolactone ( (Meth) acrylate and other alicyclic epoxy groups (meth) Acrylic monomers.

  Examples of the (meth) acrylic monomer having an oxetane group include 3-methacryloxymethyl-3-ethyloxetane, 3-acryloxymethyl-3-ethyloxetane, α, α-dimethyl-m-isopropenylbenzyl isocyanate, and And an equimolar adduct with 3-ethyl-3-hydroxymethyloxetane. These oxetane compounds may be used alone or in combination of two or more.

  Other acrylic monomers used as necessary include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, ( Examples include 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, and the like. Examples of non-acrylic monomers include xylene, vinyl toluene, vinyl acetate, acrylonitrile and the like.

  Monomers such as the (meth) acrylic monomer having the cyclic ether structure described above, other acrylic monomers, and non-acrylic monomers may be used alone or in combination of two or more.

In order to produce the compound (A) having a cyclic ether structure of the present invention, for example, 3,4-epoxycyclohexylmethyl (meth) acrylate is essential, and other acrylic monomers and non-acrylic monomers are used as raw materials as necessary. If necessary, an organic solvent such as methyl ethyl ketone or butyl acetate is added to this raw material, and a radical initiator such as azobisisobutyronitrile (AIBN) or benzoyl peroxide (BPO) is further added. Examples include a method of reacting at ~ 120 ° C for 2 hours to 15 hours. The amount of the organic solvent used when using the organic solvent is usually 60 to 150 parts by weight with respect to 100 parts by weight of the raw material.

  The molecular weight of the compound (A) is 500 to 50000 because the hardness of the obtained coating film is high, and the curability, solvent resistance, water resistance and weather resistance of the coating film are good, and the viscosity is not high and easy to use. Is preferable, 1000 to 40000 is more preferable, and 5000 to 25000 is most preferable. Here, when the compound (A) is a polymer compound, the molecular weight is a weight average molecular weight.

  The functional group equivalent of the cyclic ether structure of the compound (A) is preferably 80 to 1500 g / eq, more preferably 100 to 1000 g / eq, and most preferably 120 to 500 g / eq.

The compound (B) used in the present invention is a hydroxyl group-containing epoxy having a weight average molecular weight of 200 to 50,000 obtained by reacting an epoxy resin obtained by polymerizing glycidyl (meth) acrylate as an essential component and (meth) acrylic acid ( (Meth) acrylate. When the compound (B) is a high molecular weight compound , semi-curing (B-staging) can be achieved in a short time by thermosetting.

The compound (B) having a (meth) acryloyl group of the present invention is an epoxy (meth) acrylate , for example, a homopolymer of glycidyl (meth) acrylate, other α, β copolymerizable with glycidyl (meth) acrylate. - epoxy resins obtained by polymerizing glycidyl (meth) acrylate and copolymers of an unsaturated monomer as an essential component, Ru obtained by reacting (meth) acrylic acid. The α, β-unsaturated monomer is an α, β-unsaturated monomer that does not contain a carboxyl group because crosslinking does not occur during the copolymerization reaction with glycidyl (meth) acrylate, and is not highly viscous or gelled. The body is preferred. Examples of such α, β-unsaturated monomers not containing a carboxyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, isopropyl ( , and others acrylonitrile; meth) acrylate, (meth) acrylic acid-2-hydroxyethyl, various (meth) acrylic acid esters such as (meth) acrylic acid hydroxypropyl; styrene; vinyl acetate.

Polymerized with glycidyl (meth) acrylate as an essential component such as homopolymer of glycidyl (meth) acrylate as described above, copolymer with other α, β-unsaturated monomer copolymerizable with glycidyl (meth) acrylate An epoxy (meth) acrylate obtained by reacting an epoxy resin obtained by polymerizing glycidyl (meth) acrylate such as a polymer as an essential component with (meth) acrylic acid has a hydroxyl group in the molecular structure. involved in hydroxyl cationic polymerization by chromatic and crosslinked compound (a) and the compound (B), the coating film is obtained having a higher density.

Further, the compound (B) having a (meth) acryloyl group of the present invention may be produced using (meth) acrylate having a hydroxyl group together with glycidyl (meth) acrylate as an essential component in the production method described above.

  Examples of the (meth) acrylate having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, caprolactone or alkylene oxide adduct of each acrylate, glycerin mono ( (Meth) acrylate, glycerin di (meth) acrylate, glycidyl methacrylate-acrylic acid adduct, trimethylolpropane mono (meth) acrylate, trimethylol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) ) Acrylate, ditrimethylolpropane tri (meth) acrylate, trimethylolpropane-alkylene oxide adduct-di (meth) acrylate, etc. .

The acid value of the compound (B) of the present invention is such that it may react with a cyclic ether having cationic polymerizability even when added to the protective layer-forming sheet of the present invention, which will be described later, and the storage stability may deteriorate. The acid value of (B) is preferably 2 or less.

  The molecular weight of the compound (B) used in the present invention is easy to use without increasing the viscosity, does not evaporate at the time of heat-curing, does not reduce the hardness of the coating film, and has solvent resistance, water resistance and weather resistance of the coating film. Is preferably from 200 to 50,000, more preferably from 5,000 to 40,000. Still more preferably, it is 8000-20000. In addition, when a compound (B) is a high molecular compound, molecular weight says a weight average molecular weight.

  The equivalent of the (meth) acryloyl group of the compound (B) is preferably 80 to 1500 g / eq, more preferably 100 to 1000 g / eq, more preferably 100 to 500 g because the weather resistance of the coating film is good and the hardness is high. / Eq is most preferred. In addition, the (meth) acryloyl group in this specification means the molecular weight per double bond.

  A compound (B) may be used individually by 1 type, and may use multiple types together.

  Since the curable resin composition used in the present invention has no residual tack after semi-curing and has high hardness, the total number of moles (a) of the cyclic ether structure is more than the number of moles (b) of the (meth) acryloyl group. The number of moles (b) [(b) / (a)] of the (meth) acryloyl group with respect to the total number of moles (a) of the cyclic ether structure is more preferably 1-10. More preferably, it is 5-4.0.

The thermal cationic polymerization initiator (C) used in the present invention is, for example, a cationic polymerizable catalyst that is inactive at room temperature but cleaves when heated to reach a critical temperature to generate cations and initiates cationic polymerization. Examples of such catalysts include antimony hexafluoride ions (SbF ₆ ⁻ ), antimony tetrafluoride ions (SbF ₄ ⁻ ), arsenic hexafluoride ions (AsF ₆ ⁻ ), and phosphorus hexafluoride ions. Nitrogen onium salts, sulfur onium salts, phosphorus onium salts, and iodine onium salts containing (PF ₆ ⁻ ) as an anion component. Specifically, quaternary ammonium salt type compounds, sulfonium salt type compounds, phosphonium salt type compounds, iodonium salt type compounds, and the like can be suitably used.

  Examples of the quaternary ammonium salt type compound include N, N-dimethyl-N-benzylanilinium hexafluoride antimony, N, N-diethyl-N-benzylanilinium boron tetrafluoride, N, N-dimethyl- N-benzylpyridinium hexafluoroantimony, N, N-diethyl-N-benzylpyridinium trifluoromethanesulfonic acid, N, N-dimethyl-N- (4-methoxybenzyl) pyridinium hexafluoromonide, N, N-diethyl- N- (4-methoxybenzyl) pyridinium hexafluoride antimony, N, N-diethyl-N- (4-methoxybenzyl) toluidinium hexafluoride antimony, N, N-dimethyl-N- (4-methoxybenzyl) toluidinium hexa And antimony fluoride.

  Examples of the sulfonium salt type compounds include triphenylsulfonium boron tetrafluoride, triphenylsulfonium hexafluoride antimony, triphenylsulfonium hexafluoride arsenic, tri (4-methoxyphenyl) sulfonium hexafluoride arsenic, and diphenyl (4 -Phenylthiophenyl) sulfonium hexafluoride arsenic and the like. Examples of the products include Adeka CP-66 (Asahi Denka Kogyo), Adeka CP-77 (Asahi Denka Kogyo), and the like.

  Examples of the phosphonium salt type compound include ethyltriphenylphosphonium antimony hexafluoride, tetrabutylphosphonium antimony hexafluoride, and the like.

  Examples of the iodonium salt type compound include diphenyliodonium hexafluoride, di-4-chlorophenyliodonium hexafluoride, di-4-bromophenyliodonium hexafluoride, di-p-tolyliodonium hexafluoride And phenyl (4-methoxyphenyl) iodonium arsenic hexafluoride.

  As the thermal cationic polymerization initiator (C), a sulfonium salt compound is preferable.

  The critical temperature of the thermal cationic polymerizable catalyst initiator (C) as described above is usually about 100 to 180 ° C, more preferably 120 to 160 ° C.

  The amount of the thermal cationic polymerization initiator (C) used is such that the curing reaction proceeds sufficiently, it is easy to mix uniformly into the curable resin composition, and the water resistance of the cured coating film does not decrease. The total solid content and the solid content of the compound (B) is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight with respect to 100 parts by weight.

  The curable resin composition used in the present invention may further contain a photopolymerization initiator (D) when the active energy ray used is ultraviolet light. As the photopolymerization initiator (D), known ones can be used. Specifically, benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin propyl ether; acetophenone, 2,2-dimethoxy 2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl ketone, Acetophenones such as 2-hydroxy-2-methyl-1-phenyl-propan-1-one; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, 2-benzyl- 2-Dimethylamino-1- (4-morpholinophenyl) -buta Aminoacetophenones such as N-1, N, N-dimethylaminoacetophenone; anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 1-chloroanthraquinone; 2,4-dimethyl Thioxanthones such as thioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl)- Ketals such as phenylphosphine oxide, acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone and 4,4'-bisdiethylaminobenzophenone Other xanthones; can be mentioned 2,4,6-trimethylbenzoyl diphenylphosphine oxide, aromatic iodonium salts, sulfonium salts and diazonium salts, a polysilane compound and the like. These may be used alone or in combination of two or more. Further, a tertiary amine such as triethanolamine and a photopolymerization initiation assistant such as ethyl dimethylaminobenzoate can be used in combination. The photopolymerization initiator (D) is preferably one or more compounds selected from the group consisting of benzoins, acetophenones, and ketals. Moreover, a photoinitiator (D) may be used individually by 1 type, and may use multiple types together.

The amount of the photopolymerization initiator (D) in the curable resin composition used in the present invention can be appropriately adjusted depending on the composition of the curable resin composition. The amount of the compound (D) in the curable resin composition used in the present invention is, for example, 0.01 to 10 parts by weight with respect to the total weight of the compound (A) and the compound (B).

  In the curable resin composition used in the present invention, a compound having an active methylene or active methine group causing a Michael addition reaction is added, and by heating, a Michael addition reaction between a (meth) acryloyl group and an active methylene or active methine group is performed. The curable resin composition can also be semi-cured (B-staged).

  Examples of the compound having an active methylene or active methine group include compounds having an active methylene group such as acetoacetic acid, malonic acid, and cyanoacetic acid, and derivatives thereof; methylmalonic acid, 2-methyl-3-oxobutanoic acid, methylcyano Examples thereof include compounds having an active methine group such as acetic acid and derivatives thereof. Moreover, the compounds shown in the following (1) to (4) can also be used.

(1) a compound obtained by reacting an active methylene group-containing carboxylic acid compound and / or an active methine group-containing carboxylic acid compound with a polyhydric alcohol;
(2) a compound obtained by reacting a polyamine compound with diketene;
(3) A (meth) acrylic monomer having an active methylene group or a (meth) acrylic monomer having an active methine group as an essential component can be obtained by polymerization together with other acrylic monomers or non-acrylic monomers as necessary (meta ) Acrylic resin;
(4) a compound obtained by transesterifying methanetricarboxylic acid trialkyl ester with a polyhydric alcohol;
(5) A compound obtained by an addition reaction between an isocyanate compound and an active methylene group-containing compound.

  The compounds having an active methylene or active methine group as described above may be used alone or in combination of two or more. In addition, it may have only the same type of active methylene group or active methine group, or may have different types of active methylene groups or active methine groups, or an active methylene group and an active methine group. You may have both.

  Moreover, you may use a Michael catalyst in order to accelerate | stimulate a Michael addition reaction as needed. Examples of the Michael catalyst compound include alkali metal hydroxide, alkali metal alkoxide, quaternary ammonium hydroxide, quaternary ammonium carbonate, quaternary ammonium fluoride, quaternary ammonium tetrahydroborate, and tertiary amine. And tertiary phosphine.

  You may add additives, such as an organic solvent, a coloring agent, and a slip agent, to the cured resin composition used by this invention.

  The organic solvent usually has a boiling point of 50 to 180 ° C. because it has good workability during coating and quick drying before curing. For example, methyl acetate, ethyl acetate, butyl acetate, ethylene glycol mono Examples include ester solvents such as ethyl ether, ethylene glycol monoethyl ether acetate, and ethylene glycol monobutyl ether acetate; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; aromatic solvents such as toluene and xylene. The organic solvent may be used alone or in combination of two or more. Although the usage-amount of an organic solvent is not specifically limited, Usually, it is the range from which the solid content concentration of a coating agent will be 5-70 weight%.

  The colorant is not particularly limited. For example, extender pigments, white pigments, black pigments, gray pigments, red pigments, brown pigments described in the Paint Raw Materials Handbook 1970 edition (edited by the Japan Paint Industry Association) Organic pigments and inorganic pigments such as green pigments, blue pigments, purple pigments, metal powder pigments, luminescent pigments, and pearl pigments, and plastic pigments. A single colorant may be used, or two or more colorants may be used in combination.

  When the slip agent is contained, the protective layer of the protective layer forming sheet is roughened, so that the protective layer forming sheet is easily wound as a sheet, and blocking is less likely to occur. In addition, resistance to rubbing and scratching can be increased. Examples of the slip agent include waxes such as polyethylene wax, paraffin wax, synthetic wax and montan wax, and synthetic resins such as silicone and fluorine. The slip agent is sufficient for preventing blocking and friction scratch resistance, and for ensuring the transparency of the protective layer. The slip agent is used for 100 parts by weight of the solid content in the curable resin composition used in the present invention. 0.01 to 15 parts by weight is preferable, and 0.03 to 6 parts by weight is particularly preferable.

  Examples of the base sheet used in the present invention include a plastic sheet, a metal foil, a cellulose sheet, and a composite of these sheets.

  Examples of the plastic sheet include a polyethylene terephthalate sheet, a polypropylene sheet, a polyethylene sheet, a polycarbonate sheet, a polyolefin sheet, a polystyrene sheet, a polyamide sheet, and a polyester sheet.

  Examples of the metal foil include aluminum foil and copper foil. Examples of the cellulose sheet include glassine paper, coated paper, and cellophane.

  The base sheet is preferably a plastic sheet, and more preferably a polyester sheet. Moreover, 6-300 micrometers is preferable and, as for the thickness of a base sheet, 10-200 micrometers is more preferable.

  In order to produce the protective layer forming sheet of the present invention, first, the curable resin composition used in the present invention is coated on the base sheet. In the method for forming a protective layer, which will be described later, this resin composition is the outermost layer on the surface of the molded product, and is a layer for protecting the molded product and the pattern layer on the molded product from chemicals and friction. Examples of the method for applying the curable resin composition used in the present invention include a gravure coating method, a roll coating method, a spray coating method, a lip coating method, a coating method such as a comma coating method, a gravure printing method, and a screen printing method. The printing method etc. are mentioned. When painting, since the wear resistance and chemical resistance are good, it is preferable to coat so that the thickness of the B-staged resin layer is 0.5 to 30 μm. It is more preferable to paint so that it will be-6 micrometers.

  If the adhesive force between the base sheet and the curable resin composition is not sufficient when the curable resin composition is applied on the base sheet, 1. A primer is applied to the surface of the base sheet on which the curable resin composition is to be applied, and the curable resin composition is applied thereto. The adhesiveness between the base sheet and the curable resin composition can be improved by a method of activating the surface of the base sheet by corona discharge or the like. 1 above. As a primer to be used in, for example, a thermosetting resin such as a two-component curable urethane resin, a melamine resin, and an epoxy resin, a thermoplastic resin such as an aqueous latex made of a vinyl chloride copolymer resin, and an acrylic resin is used. Can do. Examples of methods for applying these include coating methods such as gravure coating, roll coating, and comma coating, and printing methods such as gravure printing and screen printing.

  A pattern layer may be formed on the protective layer forming sheet of the present invention for the purpose of imparting design properties. The pattern layer is printed on the base sheet before the coating of the curable resin composition, or is formed as a printed layer on the back side of the base sheet coated with the curable resin composition. As the material of the printing layer, a binder such as polyvinyl resin, polyamide resin, polyester resin, polyacrylic resin, polyurethane resin, polyvinyl acetal resin, polyester urethane resin, cellulose ester resin, alkyd resin, etc. And a color ink containing an appropriate color pigment or dye as a colorant may be used. As a method for forming the pattern layer, for example, a normal printing method such as an offset printing method, a gravure printing method, a screen printing method, or the like may be used. In particular, the offset printing method and the gravure printing method are suitable for performing multicolor printing and gradation expression. In the case of a single color, a coating method such as a gravure coating method, a roll coating method, a comma coating method, or a lip coating method may be employed. The pattern layer may be provided entirely or partially depending on the pattern to be expressed. The pattern layer may be a metal vapor deposition layer or a combination of a printed layer and a metal vapor deposition layer.

  When the pattern layer is formed, if the adhesive force between the pattern layer and the base sheet is not sufficient even when printing on the base sheet in the previous stage of applying the curable resin composition, the base sheet is used. The adhesiveness between the picture layer and the base sheet can be improved in the same manner as when the adhesive strength between the curable resin composition and the curable resin composition is improved.

  After coating the curable resin composition on the substrate sheet, the active energy ray is irradiated. By irradiation with this active energy ray, the (meth) acryloyl group in the curable resin composition is bonded by radical polymerization reaction, a three-dimensional cross-linking is formed, and the curable resin composition is semi-cured (B-staged).

  When a curable resin composition containing an organic solvent is used as the curable resin composition, the organic solvent may be removed after coating on the base sheet. In order to remove the organic solvent, for example, it may be after irradiation with active energy rays or before irradiation with active energy rays. As a method for removing the organic solvent, it may be left as it is to evaporate or may be dried using a dryer or the like, but the temperature at the time of removing the organic solvent is usually 70 to 130 ° C. for 10 seconds. About 10 minutes is preferable.

  Since the protective layer on the protective layer-forming sheet of the present invention can be easily overprinted with another layer or wound up on the protective layer, the protective layer can be tacked before irradiation with active energy rays. It is desirable to be free. For this reason, it is preferable to combine the compound (A) and the compound (B) so that the protective layer on the protective layer-forming sheet of the present invention is tack-free before irradiation with active energy rays.

Examples of the active energy ray used for forming the B-stage on the protective layer forming sheet of the present invention include an electron beam, an ultraviolet ray, and a gamma ray. Irradiation conditions are determined according to the composition of the curable resin composition used to obtain the protective layer, but in the case of ultraviolet irradiation, it is preferable to irradiate so that the integrated light quantity is usually 50 to 5000 mj / cm ^2. It is more preferable to irradiate so that the integrated light quantity is 500 to 2000 mj / cm ² . Moreover, when irradiating an electron beam, it is preferable that it is a 1-5 Mrad irradiation amount.

  The configuration of the protective layer forming sheet is not limited to the above-described embodiment. For example, the protective layer forming sheet is used only for surface protection treatment by taking advantage of the ground pattern and transparency of the molded product. In this case, the B-staged resin layer and the adhesive layer are sequentially formed on the base sheet as described above, and the pattern layer can be omitted from the protective layer forming sheet.

  Moreover, when the protective layer forming sheet has a pattern layer or an adhesive layer on the B-staged resin layer, an anchor layer may be provided between these layers. The anchor layer is a resin layer for improving the adhesion between these layers and protecting the molded product and the pattern layer from chemicals. For example, heat is applied to two-component curable urethane resin, melamine resin, epoxy resin, etc. Thermoplastic resins such as curable resins and vinyl chloride copolymer resins can be used. As a method for forming the anchor layer, there are a coating method such as a gravure coating method, a roll coating method and a comma coating method, and a printing method such as a gravure printing method and a screen printing method.

  Next, a method for forming the protective layer of the molded product of the present invention will be described. In the method for forming a protective layer of the molded product of the present invention, the base sheet supporting the protective layer-forming sheet of the present invention and the molded product were bonded, and then heated to be B-staged on the outermost surface. The resin layer is cured.

  The molded product is not limited in material, and examples thereof include a resin molded product, a woodwork product, and a composite product thereof. These may be transparent, translucent, or opaque. The molded product may be colored or not colored. Examples of the resin include general-purpose resins such as polystyrene resin, polyolefin resin, ABS resin, and AS resin. Also, general engineering resins such as polyphenylene oxide / polystyrene resins, polycarbonate resins, polyacetal resins, acrylic resins, polycarbonate modified polyphenylene ether resins, polyethylene terephthalate resins, polybutylene terephthalate resins, ultrahigh molecular weight polyethylene resins, and polysulfone resins. Super engineering resins such as polyphenylene sulfide resins, polyphenylene oxide resins, polyacrylate resins, polyetherimide resins, polyimide resins, liquid crystal polyester resins, and polyallyl heat-resistant resins can also be used. Furthermore, composite resins to which reinforcing materials such as glass fibers and inorganic fillers are added can also be used.

  As a method for forming the protective layer of the molded product of the present invention, for example, the base layer sheet of the protective layer forming sheet and the molded product are bonded, and then thermally cured by heating to form a B-stage. A method of curing (post-adhesion method) or the protective layer forming sheet is sandwiched in a molding die, and a resin is injected and filled into the cavity to obtain a resin molded product, and at the same time the surface and the protective layer forming sheet And a method in which the resin layer is cured by heating and then cured by heating (simultaneous molding adhesion method).

  Examples of the method for adhering the molded article and the protective layer forming sheet in the post-adhesion method include, for example, applying a base material sheet of the protective layer forming sheet and / or the surface of the molded article to apply the adhesive to the surface of the protective layer forming sheet Method of adhering to the surface of the molded product, after applying the double-sided adhesive tape to the base sheet of the protective layer forming sheet or / the surface of the molded product, peeling the release protective sheet of the double-sided adhesive tape to expose the adhesive surface to protect Method of adhering the base sheet of the layer forming sheet and the surface of the molded product, and applying the adhesive to the base sheet of the protective layer forming sheet to form an adhesive surface, and then protecting the adhesive surface with a release protective sheet Is prepared in advance, and the peeling protective sheet of the protective layer forming sheet is peeled off, and the adhesion surface of the base sheet and the surface of the molded product are adhered. In the simultaneous molding method, the protective layer forming sheet and the molded product are integrated by integrating the protective layer forming sheet and the molded product by melting the base sheet by heat during in-mold molding without using an adhesive. Can be glued. Here, examples of the adhesive used in the post-adhesion method include urethane adhesives, epoxy adhesives, ester adhesives, acrylic adhesives, and hot melt adhesives.

  The heating condition when the protective layer of the B-staged protective layer forming sheet is thermally cured by heating to carry out cross-linking curing is preferably a heating method using far-infrared rays or hot air, usually at 80 to 180 ° C. for 20 seconds. 10 minutes, but when forming a protective layer of a molded product by the simultaneous molding method, the heating is omitted because the thermosetting reaction proceeds at the resin melting temperature when the molten resin is injection molded. Can do.

Below, the formation method of the protective layer of the molded article by the said back adhesion method is demonstrated concretely. First, a protective layer forming sheet is placed on the molded product with the adhesive layer side down. Next, a heat resistant rubber-like elastic body, for example, a heat transfer rubber set to conditions of a temperature of 80 to 260 ° C. and a pressure of 50 to 200 kg / m ² using a transfer machine such as a roll transfer machine or an up-down transfer machine equipped with silicon rubber. Heat or / and pressure is applied from the protective layer side of the protective layer forming sheet through the elastic body. By doing so, the adhesive layer adheres to the surface of the molded product. Finally, by heating, the resin layer formed on the molded product is completely cross-linked and cured to form a protective layer.

  Next, a method for forming a protective layer of a molded article by a simultaneous molding adhesion method using injection molding will be specifically described. First, a protective layer forming sheet is fed into a molding die composed of a movable mold and a fixed mold with the adhesive layer inside, that is, the base sheet is in contact with the fixed mold. At this time, a single sheet of protective layer forming sheet may be fed one by one, or a necessary part of a long protective layer forming sheet may be intermittently fed. In the case of using a long protective layer forming sheet, it is preferable to use a feeding device having a positioning mechanism so that the registration of the pattern layer of the protective layer forming sheet and the molding die coincide. In addition, when the protective layer forming sheet is intermittently fed, it is always the same if the protective layer forming sheet is fixed between the movable type and the fixed type after the position of the protective layer forming sheet is detected by the sensor. It is convenient because the protective layer forming sheet can be fixed at the position, and the pattern layer is not displaced. After closing the molding die, the molten resin is injected and filled into the die from the gate provided on the movable die, and at the same time as forming the molded product, the protective layer forming sheet is adhered to the surface. After the resin molded product is cooled, the molding die is opened and the resin molded product is taken out. Finally, the resin layer is completely crosslinked and cured by heating in a hot air oven or the like to form a protective layer.

  The curable resin composition used in the present invention is coated on a substrate sheet, and then irradiated with an active energy ray to produce a transfer material having a coating layer in which the curable resin composition is B-staged. You can also. As the base sheet to be used, those having releasability are preferable. In addition, when the curable resin composition used in the present invention is coated on a substrate sheet, a release agent may be applied to the substrate sheet to form a release layer as necessary. Examples of the release agent for forming the release layer include melamine resin release agents, silicone resin release agents, fluororesin release agents, cellulose derivative release agents, and urea resin release agents. Polyolefin resin release agents, paraffin release agents, composite release agents thereof, and the like can be used. Examples of the method for forming the release layer include a coating method such as a gravure coating method, a roll coating method, a spray coating method, a lip coating method and a comma coating method, a printing method such as a gravure printing method and a screen printing method. After the B-staged resin layer of this transfer material is bonded to the molded product, it is heated to cure the B-staged resin layer, thereby having a protective layer excellent in scratch resistance and solvent resistance. A molded product can be obtained.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. Parts and percentages in the examples are based on weight.

Synthesis Example 1 [Synthesis of polymer (A) having a cyclic ether structure]
Into a reaction apparatus equipped with a stirrer, a cooling pipe, a dropping funnel and a nitrogen introduction pipe, 463 g of butyl acetate was charged, and the temperature of the system was increased to 110 ° C. while stirring. Next, cyclomer M100 [3,4-epoxycyclohexylmethyl (meth) acrylate, manufactured by Daicel Chemical Industries, Ltd .: purity 96.8%. ] A mixed solution consisting of 463 g and 9.3 g of t-butylperoxy-2-ethylhexanoate (manufactured by Nippon Emulsifier: Perbutyl O) was dropped from the dropping funnel over 2 hours. After dropping, the temperature was maintained at 110 ° C. for 5 hours, then the temperature was raised to 120 ° C., and the reaction was continued at the same temperature for 8 hours. After completion of the reaction, 223 g of butyl acetate was charged to obtain 920 g of a compound having a cyclic ether structure. This is called a polymer (A). Polymer (A) is non-volatile content: 41.9%, Gardner viscosity (25 ° C.): D-E ² , Gardner color: 1 or less, GPC styrene conversion weight average molecular weight: 20,700, solid content conversion epoxy Equivalent: 196 mg KOH / g.

Synthesis Example 2 [Synthesis of polymer (B) having (meth) acryloyl group]
A reactor equipped with a stirrer, a cooling tube, a dropping funnel and a nitrogen introducing tube was charged with 1200 g of butyl acetate, and the temperature was raised until the system temperature reached 110 ° C. while stirring. Next, a mixed solution composed of 1200 g of glycidyl methacrylate and 24 g of perbutyl O was dropped from a dropping funnel over 2 hours. After dropping, the temperature was maintained at 110 ° C. for 7 hours, then the temperature was raised to 120 ° C., and the reaction was continued at the same temperature for 8 hours. Next, nitrogen was changed to dry air, the temperature was lowered to 90 ° C., 1.82 g of methoquinone and 621 g of acrylic acid were charged, 17.7 g of triphenylphosphine was added, the temperature was raised to 100 ° C., and the reaction was continued for 8 hours. Continued. After completion of the reaction, 1160 g of methyl ethyl ketone (MEK) and 680 g of butyl acetate were charged to obtain 4550 g of a compound having an acroyl group. This is called a polymer (B). The polymer (B) has a non-volatile content: 37.7%, a Gardner viscosity (25 ° C.): C ² -D, a Gardner color: 1 or less, an acid value: 1.0 mg KOH / g, and a styrene-converted weight average molecular weight by GPC: 25, 600, acrylic equivalent in terms of solid content: 218 g / eq, hydroxyl value in terms of solid content: 258 mg KOH / g.

Synthesis Example 3 [Synthesis of acrylic rubber-like elastic body (X)]
182 g of methyl methacrylate, 10 g of butyl acrylate, 8 g of 1,3-butylene glycol dimethacrylate and 0.6 g of t-butyl hydroperoxide (initiator) are mixed to obtain a mixture (I) composed of a polymerizable monomer and an initiator. It was. In an autoclave with a capacity of 5 L equipped with a stirrer, 2.5 kg of deionized water, 10 g of boric acid, 1 g of sodium carbonate, 0.001 g of ferrous sulfate, 0.004 g of disodium ethylenediaminetetraacetate and an emulsifier (N-lauroyl monkey) 5 g of sodium kosine (the same shall apply hereinafter) and 80 g of the above mixture (I) and the initiator are put in a lump and nitrogen gas is blown into a state substantially free from the influence of oxygen. Then, a 10% aqueous solution of sodium formaldehyde sulfoxylate (hereinafter SFS) was added, and polymerization was carried out for 60 minutes. Thereafter, the remaining 120 g of the mixture (I) was continuously added for polymerization for 30 minutes, and polymerization was continued for 90 minutes after the addition was completed.

  Further, after adding 2 g of SFS and 5 g of emulsifier in 50 g of deionized water, 648 g of butyl acrylate, 140 g of styrene, 8.8 g of triallyl isocyanurate, 3.2 g of 1,3-butylene glycol dimethacrylate and t -3.2 g of butyl hydroperoxide (initiator) was mixed and 800 g of a mixture of polymerizable monomer and initiator (II) was added continuously for 150 minutes, and polymerization was continued for 180 minutes after the addition was completed. Continued.

  Next, 50 g of 10% emulsifier aqueous solution was added, the internal temperature was maintained at 80 ° C., and polymerization obtained by mixing 475 g of methyl methacrylate, 25 g of methyl acrylate, and 0.9 g of t-butyl hydroperoxide (initiator) was obtained. The mixture (III) composed of the polymerizable monomer and the initiator and 2.4 g of n-octyl mercaptan were continuously added for polymerization for 90 minutes, and after the addition was completed, the polymerization was continued for another 60 minutes.

  A polymer latex containing an acrylic rubber-like elastic body (A) was obtained by the series of polymerization methods described above. This polymer latex was coagulated in 1% sulfuric acid water at 70 ° C., washed with deionized water, dehydrated, and air-dried at 80 ° C. to obtain an acrylic rubber-like elastic body (X) in powder form.

Synthesis Example 4 [Synthesis of acrylic resin for comparison (C)]
In a 1 L four-necked flask equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer, 60 g of methyl ethyl ketone and 1 g of an acrylic rubber-like elastic body (A) are placed under a nitrogen atmosphere, and the temperature of the hot water bath is stirred. The mixture (IV) consisting of 100 g of cyclomer M100 and 0.3 g of azobisisobutyronitrile was added dropwise over 2 hours. Subsequently, 0.7 g of azobisisobutyronitrile was added in 5 portions every 1 hour, and then the temperature in the flask was raised to the boiling point of the solvent and polymerization was performed at that temperature for another 2 hours. Thereafter, after the temperature in the flask became 50 ° C. or lower, 90 g of methyl ethyl ketone was added, and the polymerization reaction product was taken out of the flask to obtain a comparative acrylic resin (C) solution. This is called a polymer (C). The polymerization rate of the monomer mixture in the acrylic resin (C) was 99.5% or more, the solid content was about 40% by weight, the weight average molecular weight was about 210,000, and the glass transition temperature was about 74 ° C.

Example 1
A compound was blended with the composition shown in Table 1 to prepare a curable resin composition. This is abbreviated as composition M1.

  A protective layer-forming sheet was produced using the prepared composition M1. Specifically, a polyester resin sheet having a thickness of 38 μm was used as a base sheet, and an acrylic ink was printed on the sheet by a gravure printing method to form a pattern layer. The composition M1 was printed on the pattern layer by a gravure printing method so as to have a thickness of 5 μm. Then, after heating at 70 degreeC for 1 minute, the protective layer semi-hardened (B-staging) was obtained by irradiating with an ultraviolet-ray. The irradiation condition of ultraviolet rays is four times with one 80 w / cm high-pressure mercury lamp, a lamp height of 15 cm, and a conveyor speed of 5 m / min.

<Blocking resistance test>
The protective layer surface of the protective layer forming sheet and the polyester resin sheet were overlapped and sandwiched between glass plates. A 1 kg weight was placed on the glass plate and held at 40 ° C. for 1 day. Thereafter, the superposed sheets were taken out, and the sheets were separated from each other. The presence or absence of a phenomenon (blocking) in which the protective layer surface of the protective layer forming sheet was transferred to the other film was visually observed and evaluated according to the following determination.
A: Generation of blocking is not recognized. It is also smooth to separate the sheets.
○: Blocking is not observed, but resistance is felt when the sheets are separated.
X: Blocking occurs.

Using this protective layer forming sheet, the protective layer forming sheet is adhered to the surface of the molded product using the simultaneous molding method, and then heated to completely crosslink and cure the protective layer. Formed. The molding conditions were a resin temperature of 240 ° C., a mold temperature of 55 ° C., and a resin pressure of 300 kg / cm ² . The molded product is a tray-shaped molded product made of acrylic resin and having a length of 95 mm, a width of 65 mm, a rise of 4.5 mm, and a corner of R2.5 mm.

  Using the molded article on which the protective layer was formed, a solvent resistance test and an abrasion resistance test were performed, and the presence or absence of cracks on the surface of the protective layer was also observed. Each test and the observation method of the presence or absence of a crack are shown below.

<Solvent resistance test>
MEK was impregnated with gauze, and the state of the surface of the protective layer after 50 reciprocating rubs with a load of 440 g / cm ² was visually observed and evaluated according to the following judgment.
A: No change in surface condition.
○: The surface of the protective layer dissolves and scratches occur, but scratches that reach the inside of the protective layer do not occur.
X: The protective layer dissolves and scratches reaching the inside occur.

<Abrasion resistance test>
Using # 0000 steel wool, the degree of damage on the surface of the protective layer after 50 reciprocations with a load (440 g / cm ² ) was visually observed and evaluated according to the following judgment.
A: No change in surface condition.
○: Scratches occur on the surface of the protective layer, but no scratches reach the inside of the protective layer.
X: Scratches reaching the inside occur.

<Presence of cracks>
The state of occurrence of cracks in the protective layer on the curved surface of the molded product was visually judged and evaluated according to the following judgment.
○: Cracks are not observed.
X: Crack generation is observed.

Examples 2, 3 and Comparative Examples 1-3
Compositions M2 and M3, which are curable resin compositions, and comparative control compositions M′1 to M′3 were prepared with the formulations shown in Tables 1 and 2. In the same manner as in Example 1, the protective layer-forming sheet was produced and the protective layer of the molded product was formed. The same tests as in Example 1 were performed and the results are shown in Tables 3 and 4.

Comparative Example 3
100 parts of acrylic resin A, 1 part of Sun-Aid SI-100L (Triphenylsulfonium hexafluoride antimonate manufactured by Sanshin Chemical Industry Co., Ltd.) and 1 part of acrylic rubber-like elastic body (A) are mixed for comparison. A curable resin composition M′3 was prepared. In the same manner as in Example 1, a protective layer-forming sheet was produced and a protective layer for a molded article was formed. Each test similar to Example 1 was done and the result is shown in Table 4.

<Footnotes in Tables 1 and 2>
SH28PA: SH28PA [manufactured by Toray Dow Corning Co., Ltd.], which is a silicone slip agent, is diluted with MEK so as to have a nonvolatile content of 10%.
Irgacure 184: Photopolymerization initiator (Ciba Geigy)
SI-110: A sulfonium-based thermal cationic polymerization initiator SI-110 (manufactured by Sanshin Chemical Co., Ltd.) diluted with MEK so as to have a nonvolatile content of 20%.

Claims (7)

After coating a curable resin composition containing a compound (A) having a cyclic ether structure, a compound (B) having a (meth) acryloyl group and a thermal cationic polymerization initiator (C) on a base sheet, an active energy ray the irradiated a coercive Mamoruso formation sheet that having a coating layer formed by B- staged the curable resin composition, a compound having a cyclic ether structure (a) is 3,4-epoxycyclohexylmethyl It is an alicyclic epoxy (meth) acrylic resin having a weight average molecular weight of 500 to 50,000 obtained by polymerizing (meth) acrylate as an essential component, and the compound (B) having a (meth) acryloyl group is glycidyl (meth) acrylate. Weight average molecular weight 200-5000 obtained by reacting an epoxy resin obtained by polymerizing as an essential component with (meth) acrylic acid And the number of moles of the (meth) acryloyl group in the compound (B) relative to the number of moles (a) of the cyclic ether structure in the compound (A) (b) [(b) / (A)] is 1 to 10, a protective layer forming sheet. Functional group equivalent of the cyclic ether structure in the compound (A) in 80~1500g / eq, protected equivalent of (meth) acryloyl groups in the compound (B) is according to claim 1 wherein the 80~1500g / eq Layer forming sheet. The thermal cationic polymerization initiator (C) a protective layer forming sheet according to claim 1, wherein the sulfonium salt compound. The protective layer-forming sheet according to any one of claims 1 to 3 , wherein the curable resin composition further contains a photopolymerization initiator (D). The protective layer-forming sheet according to claim 4, wherein the photopolymerization initiator (D) is one or more compounds selected from the group consisting of benzoins, acetophenones, and ketals. The said base sheet is 1 or more types of sheets chosen from the group which consists of a polyethylene terephthalate sheet, a triacetyl cellulose sheet, a polypropylene sheet, a polyethylene sheet, and a polystyrene sheet, The protective layer formation of any one of Claims 1-5 Sheet. After the base sheet of the protective layer forming sheet according to any one of claims 1 to 6 and a molded product are bonded, the coating layer formed into the B-stage is cured by heating. A method for forming a protective layer of a molded product.