Hard coat film, method for producing molded article using same, molded article, and molded film

Abstract

To provide a hard coat film having good moldability at low temperature and excellent flexibility at normal temperature and suitable for film molding, a method for producing a molded article using the same, a molded article and a molded film.SOLUTION: The hard coat film has a cured layer of a photocurable resin composition on a polypropylene substrate, wherein the tensile elongation at break of the hard coat film at 130 °C is 50 to 400%, and the polypropylene substrate does not contain a nucleating agent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hard-coated film having excellent formability, and further to a method for producing a molded article using the same, the molded article, and a molded film. [Background technology]

[0002] Conventionally, spray painting has been the standard method for coloring automotive exterior parts, such as fenders, bumpers, and hoods. However, this method requires repeated painting and drying, which requires large equipment, space, and labor. It also consumes a huge amount of energy, and when the paint is solvent-based, evaporation increases the environmental impact, posing many problems.

[0003] To address these issues, there is a film molding method that uses pre-colored decorative film. Compared to methods using paints such as spray painting, this method allows for greater design freedom, makes it easy to decorate surfaces with three-dimensional irregularities, and is widely adopted for its excellent productivity. Well-known examples include insert molding, in which a design is printed on the film surface, which is then heated to soften it and subjected to three-dimensional molding, after which it is set in a mold and injection molded, and TOM molding, which involves vacuum and pressure molding on a pre-formed substrate.

[0004] Formed films used in these molding methods typically have a hard coat (hereinafter referred to as HC) layer to improve surface hardness and scratch resistance. However, if the HC resin layer is made too hard, microcracks will occur on the curved surface when the film is processed into a three-dimensional shape, making molding difficult. For this reason, the applicant previously invented a hard coat agent containing a triazine ring-containing (meth)acrylate prepolymer and organic fine particles with an average primary particle size of 80 to 500 nm (Patent Document 1). This composition was an excellent HC agent that had a film thickness of 1 to 10 μm and was capable of achieving both sufficient flexibility and surface properties.

[0005] By selecting the right HC agent for these molding applications, processing constraints have been alleviated to some extent. However, as the applications of film molding expand, new technical challenges and required properties have emerged. For example, in the case of large-size insert molding, chipping and cracking can occur during the process from preforming to setting in the injection molding mold, resulting in reduced yields. Furthermore, in TOM molding, when molding onto substrates with relatively low heat resistance, moldability at lower temperatures is sometimes required to minimize damage to the substrate. Therefore, there is a growing demand for moldable HC films that are easy to handle and flexible at room temperature, while also allowing molding at lower temperatures. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4848200 Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide an HC film suitable for film molding applications, which has good moldability at low temperatures and excellent flexibility at room temperature, as well as a method for manufacturing a molded article using the same, a molded article, and a molded film. [Means for solving the problem]

[0008] In order to solve the above problems, the invention of claim 1 provides a hard coat film having a cured layer of a photocurable resin composition on a polypropylene substrate, wherein the hard coat film has a tensile elongation at break of 50 to 400% at 130°C, and the polypropylene substrate does not contain a nucleating agent.

[0009] A second aspect of the present invention provides the hard coat film according to the first aspect, wherein the photocurable resin composition contains a polyfunctional urethane (meth)acrylate.

[0010] The invention of claim 3 provides a hard-coated film according to claim 1, characterized in that the moldable temperature when the hard-coated film is vacuum-pressure molded using a cylindrical mold of 30 mm diameter x 20 mm height is 125°C or less.

[0011] The invention of claim 4 provides a method for producing an insert-molded article, in which the hard coat film according to any one of claims 1 to 3 is shaped using a mold, and then molten resin is injected from the side opposite to the photocurable resin cured layer to form a resin molded article.

[0012] The invention of claim 5 provides an insert molded article or an out-molded article using the hard coat film of any one of claims 1 to 3.

[0013] The invention of claim 6 provides a molded film characterized by further comprising a decorative layer and / or a pressure-sensitive adhesive layer in addition to the hard coat film of any one of claims 1 to 3. [Effects of the Invention]

[0014] The HC film of the present invention has high elongation at break, good formability at low temperatures, and excellent flexibility at room temperature, and is therefore useful as an HC film for use in film forming such as insert molding and out-molding. BEST MODE FOR CARRYING OUT THE INVENTION

[0015] The HC film of the present invention has a cured layer of a photocurable resin composition on a polypropylene substrate that does not contain a nucleating agent. The photocurable resin composition preferably contains a multifunctional urethane (meth)acrylate. In this specification, (meth)acrylate includes both acrylate and methacrylate, and (poly)ethylene glycol includes both ethylene glycol and polyethylene glycol.

[0016] The polypropylene base material is a crystalline olefin-based thermoplastic resin, and generally has the properties of heat resistance, oil resistance, and low heat distortion temperature. In this specification, polypropylene refers to a polymer containing at least polypropylene, specifically homopolypropylene and copolymers with other olefins.

[0017] The polypropylene substrate used in the present invention does not contain a nucleating agent. A nucleating agent is an additive that promotes the crystallization of polymers, shortening the induction period until crystal growth and improving the crystallization rate of the polymer. Therefore, without the addition of a nucleating agent, productivity decreases and the crystals tend to become non-uniform, which may affect moldability. On the other hand, when a nucleating agent is added, the presence of a substance that acts as a nucleus for crystals tends to reduce transparency. Furthermore, because crystallization proceeds relatively quickly, the intermolecular bond strength tends to increase, which tends to reduce flexibility and increase the molding temperature. In the present invention, by combining a cured layer with high tensile elongation at break with a polypropylene substrate that does not contain a nucleating agent, the transparency of the film and moldability were improved.

[0018] The polypropylene substrate may be subjected to a surface treatment to improve adhesion to the composition, such as a primer treatment, a sandblasting method, a solvent treatment, or the like to create a rough surface, or a surface oxidation treatment such as a corona discharge treatment, a chromic acid treatment, or an ozone / ultraviolet irradiation treatment.

[0019] The thickness of the polypropylene substrate is not particularly limited, and may be set appropriately depending on the application, for example, from 50 to 500 μm. Commercially available products include Pure Thermo AG-356AS (trade name: manufactured by Idemitsu Unitech Co., Ltd., 200 μm thick, polypropylene film containing no nucleating agent).

[0020] The photocurable resin composition (hereinafter referred to as the present composition) used in the present invention is cured by light such as ultraviolet light to form an HC layer. The present composition contains a binder resin. For example, oligomers include acrylic resin binders such as urethane (meth)acrylate (hereinafter referred to as urea), epoxy (meth)acrylate, polyester (meth)acrylate, polycarbonate (meth)acrylate, acrylic (meth)acrylate, and diene (meth)acrylate, and these can be used alone or in combination of two or more.

[0021] Among these, it is preferable to include ureac, which has abrasion resistance and toughness due to the cohesive force of hydrogen bonds derived from urethane bonds. Ureac can be obtained, for example, by reacting a urethane prepolymer obtained by reacting a polyol with an excess of polyisocyanate with a (meth)acrylate having a hydroxyl group, or by reacting a polyisocyanate with a (meth)acrylate having a hydroxyl group, and is not particularly limited.

[0022] The number of functional groups in the ureac is preferably 2 to 10, more preferably 3 to 8, and particularly preferably 4 to 6. By making it 2 or more functional, sufficient curability and adhesion to the adherend can be ensured, and by making it 10 or less functional, excessive curing can be suppressed and sufficient breaking elongation required for a molding film can be ensured.

[0023] The synthesis method of the urea is not particularly limited, and known methods can be used. The reaction can be carried out without a solvent; however, as the molecular weight increases, the viscosity increases, making stirring difficult. Therefore, ketones such as butanone, or aromatic inert solvents such as xylene can be used. Furthermore, it is preferable to use a catalyst for the reaction between the hydroxyl group of the (meth)acrylate and the isocyanate group. Examples of such a catalyst include tin-based catalysts such as dibutyltin dilaurate, and metal alkoxide-based catalysts such as cobalt naphthenate. The reaction temperature can be set as appropriate, but is preferably 40 to 120°C, and more preferably 60 to 100°C.

[0024] Examples of polyols used in the synthesis of ureac include glycols, polyethers, polyesters, polycarbonates, and polydienes. Specific examples include alkylene glycols such as ethylene glycol and propylene glycol, polyethers such as polyethylene glycol and polypropylene glycol, and polyesters obtained by reacting these with dicarboxylic acids. These can be used alone or in combination of two or more. Among these, alkylene glycol polyols and polyether polyols are preferred. Furthermore, ethylene glycol is preferred because it has a short carbon chain and can increase the urethane bond concentration in the molecule, and polyethylene glycol is preferred because it can improve the ductility of the cured product and ensure good moldability.

[0025] Examples of polyisocyanates used in the synthesis of ureac include aliphatic types such as hexamethylene diisocyanate and tetramethylene diisocyanate, alicyclic types such as isophorone diisocyanate (hereinafter referred to as IPDI), cyclohexane diisocyanate and hydrogenated xylylene diisocyanate, aromatic types such as diphenylmethane diisocyanate and tolylene diisocyanate, and their trimers such as isocyanurates and biuret types, which can be used alone or in combination of two or more. Among these, aliphatic and alicyclic diisocyanates are preferred because they have high weather resistance and are less likely to yellow, and IPDI is particularly preferred because of its high rigidity.

[0026] Examples of (meth)acrylates having a hydroxyl group used in the synthesis of urea include monofunctional (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, bifunctional (meth)acrylates such as glycerin di(meth)acrylate, trifunctional (meth)acrylates such as pentaerythritol tri(meth)acrylate, and tetrafunctional (meth)acrylates such as dipentaerythritol tetra(meth)acrylate, which can be used alone or in combination of two types. Among these, di- and trifunctional (meth)acrylates are preferred, with pentaerythritol triacrylate (hereinafter referred to as PETA) being particularly preferred.

[0027] The weight-average molecular weight (hereinafter referred to as Mw) of the oligomer used as the binder resin is preferably 2,000 to 12,000, more preferably 3,000 to 11,000, and particularly preferably 3,500 to 10,000. By setting it to 2,000 or more, the elongation at break is high and sufficient moldability can be ensured, while by setting it to 12,000 or less, sufficient abrasion resistance and scratch resistance can be ensured. The Mw was measured and calculated by gel permeation chromatography using a column with a styrene-divinylbenzene-based packing material and a tetrahydrofuran eluent, and the molecular weight was calculated in terms of standard polystyrene.

[0028] The blending amount of the binder resin is preferably 65 to 95 wt % of the total solid content, more preferably 70 to 93 wt %, and particularly preferably 80 to 92 wt %. A blending amount of 65 wt % or more ensures sufficient moldability and flexibility, while a blending amount of 95 wt % or less ensures sufficient scratch resistance. Furthermore, when ureac is contained as the binder resin, the blending ratio of ureac in the binder resin is preferably 70 to 100%, more preferably 80 to 100%.

[0029] In the present composition, a low-molecular-weight binder may be used as a binder resin component other than the oligomer. Examples include (meth)acrylates and acrylamide compounds having an aliphatic, alicyclic, or polyether skeleton, or functional groups such as hydroxyl groups and amino groups, and these can be used alone or in combination of two or more. In terms of the number of functional groups, polyfunctional binders are preferred in terms of reactivity. Examples include pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

[0030] The composition preferably contains a photopolymerization initiator. Photopolymerization initiators generate radicals upon irradiation with ultraviolet light or electron beams, and these radicals trigger the polymerization reaction. General-purpose photopolymerization initiators such as benzyl ketals, acetophenones, and phosphine oxides can be used. By arbitrarily selecting the light absorption wavelength of the polymerization initiator, it is possible to impart curability over a wide wavelength range from the ultraviolet region to the visible light region. Specifically, benzyl ketals include 2,2-dimethoxy-1,2-diphenylethan-1-one, α-hydroxyacetophenones include 1-hydroxy-cyclohexyl-phenyl-ketone and 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, α-aminoacetophenones include 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, and acylphosphine oxides include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and these can be used alone or in combination of two or more.

[0031] Among these, it is preferable to use an α-hydroxyacetophenone-based resin that is less prone to yellowing, and commercially available products include Omnirad 127D, 184, and 2959 (trade names: manufactured by IGM Resins). The amount of photopolymerization initiator added per 100 parts by weight of the radically polymerizable component is preferably 2 to 15 parts by weight, more preferably 5 to 12 parts by weight.

[0032] It is preferable to incorporate a leveling agent into the composition. By incorporating a leveling agent, the leveling properties during application are improved, making it easier to obtain a good coating appearance. Examples include fluorine-based, silicone-based, and fluorine-silicone-based agents, which can be used alone or in combination of two or more. Among these, silicone-based polysiloxane compounds are preferred, as they can equalize the large surface tension differences on the coating surface. Examples include polyalkyl siloxanes, polyaryl siloxanes, polyalkylaryl siloxanes, polyester-modified siloxanes, and polyether-modified siloxanes, which can be used alone or in combination of two or more.

[0033] The amount of the leveling agent is preferably 0.1 to 3 wt % of the total solid content, and more preferably 0.3 to 2 wt %. By using this range, sufficient leveling properties can be ensured and a stable coating film appearance can be obtained. Commercially available products include BYK-UV3570 (trade name: BYK Chemie, acryloyl group-containing polyester-modified polydimethylsiloxane compound).

[0034] It is preferable to incorporate nano-alumina particles into this composition. By incorporating nano-alumina particles, the hardness of the cured layer can be increased, improving abrasion resistance, and in particular resistance to scratches caused by car washes. The average primary particle size of the nano-alumina particles is preferably 10 to 300 nm, more preferably 30 to 200 nm, particularly preferably 50 to 150 nm, and particularly preferably 70 to 100 nm. By making the particle size 10 nm or more, car wash scratch resistance can be improved, and by making it 300 nm or less, good optical properties can be ensured in the film.

[0035] The amount of the nano-alumina particles is preferably 0.1 to 20.0 wt. % of the total solid content of the resin composition, more preferably 0.5 to 15.0 wt. %, and particularly preferably 1.0 to 10.0 wt. By adding 0.1 wt. % or more, it is expected that the car wash scratch resistance will be improved, and by adding 20.0 wt. % or less, sufficient moldability will be ensured.

[0036] It is preferable to incorporate a light stabilizer into the composition. By incorporating a light stabilizer, deterioration of the cured film due to exposure to ultraviolet light or radiant heat when used outdoors can be reduced. Examples of light stabilizers include radical scavengers that efficiently trap alkyl radicals and peroxy radicals generated from polymers photodegraded by ultraviolet light, and ultraviolet absorbers that convert absorbed ultraviolet energy into heat energy, thereby inhibiting polymer decomposition.

[0037] Examples of the radical scavenger include hindered amines (hereinafter referred to as HALS), hindered phenols, and aromatic amines, which can be used alone or in combination of two or more. Among these, HALS is preferred because it has high radical scavenging efficiency even at low concentrations. The amount of radical scavenger added is preferably 1 to 10% by weight, more preferably 2 to 8% by weight, and particularly preferably 3 to 6% by weight, based on the total solid content. By using this range, sufficient light stability can be ensured. Commercially available HALS products include Tinuvin 123 and Tinuvin 249 (trade names: manufactured by BASF Japan Ltd.).

[0038] The UV absorber is a radical chain initiation inhibitor with an absorption band in the high-energy, harmful UV region. When used in combination with a radical scavenger, it can further improve and stabilize weather resistance. Examples include benzotriazoles, triazines, and benzophenones, which can be used alone or in combination. Among these, hydroxyphenyltriazines, which are capable of strongly absorbing the long-wavelength portion of UV light, are preferred. The amount of UV absorber is preferably 0.3 to 5 wt. % based on the total solid content, more preferably 0.5 to 3.0 wt. %, and particularly preferably 0.6 to 1.5 wt. This range ensures sufficient UV absorption characteristics. The combined amount of (E) (the radical scavenger and UV absorber) is preferably 1.0 to 12 wt. % based on the total solid content, more preferably 1.5 to 10 wt. %, and particularly preferably 4.0 to 8.0 wt. A total of 1.0 wt. % or more can be expected to improve weather resistance, while a total of 12 wt. % or less can avoid excessive incorporation and ensure sufficient adhesion to the substrate. Commercially available products include Tinuvin 460 and 477 (trade names: manufactured by BASF Japan Ltd.).

[0039] If necessary, the composition may contain a leveling agent, an inorganic filler, a light stabilizer, an adhesion promoter, a bluing agent, a pigment, an antifoaming agent, a thickener, an anti-suspending agent, an antistatic agent, an anti-fogging agent, an antibacterial agent, a wax, a matting agent, a hydrophilic agent, a water-repellent agent, organic fine particles, and the like, within the range that does not impair the performance.

[0040] When applying the composition to a plastic substrate, it may be diluted with a solvent to improve coating properties. Examples of suitable solvents include alcohol-based solvents such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and diacetone alcohol; ketone-based solvents such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as ethyl acetate and butyl acetate; ether-based solvents such as propylene glycol monomethyl ether (PGM), diethyl ether, and diisopropyl ether; and hydrocarbon-based solvents such as cyclohexane and methylcyclohexane. These solvents may be used alone or in combination. The solids content of the diluted composition is typically 10 to 70%, but there are no specific limitations and the viscosity can be adjusted appropriately to achieve a coating viscosity that is easy to apply.

[0041] The method for applying the composition is not particularly limited, and the composition can be formed by known coating methods such as spray coating, roll coating, die coating, air knife coating, blade coating, spin coating, reverse coating, gravure coating, wire bar coating, etc., or printing methods such as gravure printing, screen printing, offset printing, inkjet printing, etc. The thickness of the coated film when dried can be, for example, 1 μm to 20 μm, but is not limited to this.

[0042] The light source for UV irradiation used to cure the present composition is not particularly limited, and examples include known low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, carbon arc lamps, xenon lamps, metal halide lamps, LED lamps, and electrodeless UV lamps. The irradiation atmosphere may be air or an inert gas such as nitrogen or argon. Furthermore, the curability can be further improved by heating the coating film during UV irradiation using a back roll or an IR heater. The irradiation conditions are an irradiation intensity of 500 mW / cm. 2 ~3000mW / cm 2 , exposure dose 50-400mJ / cm 2 are exemplified, but are not limited to these.

[0043] An HC film (hereinafter referred to as the present HC film) obtained by coating the present composition on a polypropylene substrate and curing it has a breaking elongation of 50% to 400%, more preferably 100% to 300%, and particularly preferably 150 to 250% or more in an atmosphere of 130°C. By making the breaking elongation 50% or more, sufficient formability can be expected.

[0044] The present HC film may be provided with a decorative layer and an adhesive layer as necessary. A backing sheet layer may also be provided as a reinforcing layer. The arrangement of these layers relative to the substrate may be arbitrary, except that the HC layer is the uppermost layer. A laminate including a decorative layer other than the HC layer and / or an adhesive layer and / or a backing sheet layer will hereinafter be referred to as the present molded film.

[0045] Examples of the layer configuration of the present molded film include, but are not limited to, HC layer / substrate / decorative layer / adhesive layer, HC layer / decorative layer / substrate / adhesive layer, HC layer / substrate / decorative layer / backing sheet layer, HC layer / decorative layer / substrate / backing sheet layer, HC layer / substrate / adhesive layer / backing sheet layer, HC layer / decorative layer / substrate / adhesive layer / backing sheet layer, HC layer / substrate / decorative layer / adhesive layer / backing sheet layer, etc. Furthermore, a primer layer and an adhesive layer may be further disposed between each layer to improve adhesion.

[0046] The decorative layer can usually be formed using printing ink by a known printing method such as gravure printing, offset printing, silk screen printing, transfer printing, or ink jet printing. Examples of binders for printing ink include acrylic, polyester, urethane, and vinyl chloride-vinyl acetate copolymer binders, which can be used alone or in combination of two or more. In addition to these, appropriate mixtures of colorants such as pigments and dyes, stabilizers, plasticizers, curing agents, catalysts, and the like can also be used.

[0047] The colorant may be an inorganic pigment such as titanium white, red iron oxide, or ultramarine blue, an organic pigment such as Hansa Yellow A or phthalocyanine blue, a metal pigment such as aluminum or brass, a pearl pigment, or a fluorescent pigment, either alone or in combination of two or more.In addition, instead of printing ink, a film may be formed by a method such as vacuum deposition, sputtering, or electroless plating using a metal such as aluminum, indium, chromium, nickel, gold, or silver.

[0048] When printing ink is used, the thickness of the decorative layer is preferably 3 to 50 μm, more preferably 5 to 30 μm. By setting the thickness within this range, it is possible to improve hiding power and to fully express complex designs such as gradations.

[0049] The adhesive layer is typically a pressure-sensitive adhesive layer. The adhesive layer contains, for example, an acrylic, polyolefin, rubber, polyester, silicone, or polyurethane adhesive polymer. The adhesive polymer may be crosslinked with an isocyanate, epoxy, or metal chelate crosslinking agent. The adhesive layer may be thermosetting, thermoplastic, or photocurable. Among these, acrylic adhesives are preferred in terms of high transparency and weather resistance, and crosslinked acrylic adhesives are even more preferred. The adhesive layer may also contain a tackifier.

[0050] The adhesive layer can be formed by a known method using a gravure coater, a flexo coater, a roll coater, a knife coater, a comma coater, etc. Alternatively, a pressure-sensitive adhesive layer previously formed into a sheet shape may be laminated.

[0051] The thickness of the adhesive layer is preferably 10 to 100 μm, more preferably 20 to 80 μm, and particularly preferably 25 to 60 μm. A thickness of 10 μm or more can be expected to ensure good adhesion to the substrate, while a thickness of 100 μm or less can reduce protrusion from the film edge in a high-temperature environment and suppress a decrease in pencil hardness.

[0052] The backing sheet layer is arranged to provide strength during insert molding to facilitate handling during preforming, improve adhesion with the injection molding resin, suppress thermal damage during injection, and improve the hiding power of the substrate. Examples include polyethylene-based, polypropylene-based, polyester-based, polyurethane-based, polyvinyl chloride-based, and acrylonitrile butadiene styrene (hereinafter referred to as ABS-based). The backing sheet layer may be colored.

[0053] The heat distortion temperature (deflection temperature under load) of the backing sheet is preferably 85 to 120°C. By setting the heat distortion temperature to 85°C or higher, it is possible to sufficiently suppress deformation and distortion due to heat when drying the printing ink of the decorative layer, and by setting the heat distortion temperature to 120°C or lower, it is not necessary to raise the temperature when preforming the formed film, and variations in elongation and distortion during preforming can be sufficiently suppressed. Therefore, polypropylene (deflection temperature under load: 100°C), ABS-based materials (deflection temperature under load: 95°C), etc. are preferred as materials for the backing sheet.

[0054] A protective film may be attached to the molding film to protect the surface to which the composition is applied. By using a protective film, scratches can be prevented during insert molding or out-molding processes. Yield improvement can be expected.

[0055] The present molding film can be used in insert molding, for example, by placing the surface coated with the present composition facing the inner wall of the mold (so that the surface opposite the cured layer of the present composition is in contact with the molding resin), preforming the present HC film to the shape of the mold as needed, and then closing the mold to inject the molten molding resin into the cavity and solidifying the resin to form a resin molded product.

[0056] The preforming method may be a method in which the HC film is preheated to above its softening point and placed in a mold, followed by vacuum suction through suction holes in the mold, or a known molding method such as vacuum forming, compressed air forming, or press molding using a molding mold separate from the injection molding mold. It is also possible to simultaneously perform molding and integral molding of the injected resin by the injection pressure of the molding resin without performing these preforming methods.

[0057] The resin to be injection-molded can be any known resin that can be injection-molded. Examples include polyethylene resin, polypropylene resin, polystyrene resin, ABS resin, AS resin, acrylic resin, urethane resin, polyester resin, polycarbonate resin, polyphenylene ether resin, polyacetal resin, and polysulfone resin. These resins can be used alone or in combination of two or more. For large sizes, such as automobile bodies, or for small sizes with thin walls, warping and other problems can be avoided by approximating the shrinkage rate after molding to that of HC film. When insert-molding this molded film, the surface that adheres to the injected resin is preferably a backing sheet layer or an adhesive layer.

[0058] By using a molding HC film with a polypropylene base material and integrating the HC film base material with the injection molding resin, such as injection molding with polypropylene resin, it becomes possible to create a mono-material molded product. Molded products made of a mono-material are easy to recycle because there is no need to separate them by material when discarding them, and by preventing the mixing of materials when recycling, the quality of the recycled product can be improved.

[0059] Furthermore, this molded film can also be used for out-molding. For example, it can be used for TOM (Three-Dimensional Overlay Method) molding. TOM molding is a film molding method in which a pre-formed substrate is subjected to three-dimensional surface decoration using vacuum and pressure molding inside an airtight box. By using this molded film, it is possible to handle large three-dimensional products regardless of the substrate material. When using this molded film for TOM molding, it is preferable that the surface that comes into contact with the molded product is an adhesive layer.

[0060] The present invention will be described in detail below with reference to examples and comparative examples, but these are intended to be specific examples and are not intended to limit the scope of the present invention. Unless otherwise specified, measurements were carried out at a room temperature of 25°C and a relative humidity of 65%. The blend amounts are expressed in parts by weight as solid content. [Example]

[0061] Preparation of ureac 1 A four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 200 parts by weight of ethylene glycol, 825 parts by weight of IPDI (NCO group 37.5%), a catalyst, and MEK (50% solids). The mixture was stirred and reacted at 80°C for 6 hours. The reaction was terminated when the isocyanate group peak reached a predetermined level by infrared absorption analysis. Next, 438 parts by weight of PETA (hydroxyl value 120 mg KOH / g) was added and the mixture was stirred and reacted at 70°C for 6 hours. After confirming the disappearance of the isocyanate groups by infrared absorption analysis, the solids were adjusted to 50% with MEK to yield 1, a hexafunctional urea with a molecular weight of 6,200 (number average molecular weight 2,800).

[0062] Following the above-mentioned manufacturing method, Ureac 2, which has the same skeleton as Ureac 1 but a different Mw, was obtained, and Ureac 3 was obtained by using polyethylene glycol instead of ethylene glycol. Ureac 2: PETA-IPDI-(ethylene glycol-IPDI)n-PETA backbone, 6 functional groups, solid content 50%, Mw 3,200 Ureac 3: PETA-IPDI-polyethylene glycol-IPDI-PETA backbone; 6 functional groups, solid content 50%, Mw 6,000

[0063] Formulation examples 1~7 The above-prepared Ureacs 1 to 3 and DPHA were used as binder resins, Omnirad 2959 and 127D (trade names: manufactured by IGM Resins) were used as photopolymerization initiators, BYK-UV3500 (trade name: manufactured by BYK Chemie, an acryloyl group-containing polyester-modified polydimethylsiloxane compound) was used as a leveling agent, nanoalumina fine particles with an average particle size of 70 nm were used as nanoalumina, and Tinuvin 249 and Tinuvin 477 (trade names: manufactured by BASF Japan) were used as light stabilizers in the formulation shown in Table 1. These were stirred until uniformly dissolved and dispersed, and PGM was further added to the mixture so that the solid content was 30%, followed by dilution and stirring to obtain photocurable resin compositions of Formulation Examples 1 to 7.

[0064] Plastic substrate for evaluation As the plastic substrates, polypropylene, PET, polycarbonate (hereinafter referred to as PC), acrylic, and acrylic / PC composite substrates were used, as described below. Polypropylene 1 (hereinafter referred to as PP1): Pure Thermo AG-356AS (product name: Idemitsu Unitech Co., Ltd., 200 μm thick, polypropylene film without nucleating agent) Polypropylene 2 (hereinafter referred to as PP2): Clearne PPS-C (product name: Seedam, 200 μm thick, polypropylene film containing nucleating agent) PET: U403 (product name: Toray Industries, thickness 100 μm) PC: PC-1151 (product name: Teijin, thickness 200 μm) Acrylic: HBA007P (product name: Mitsubishi Chemical Corporation, thickness 75 μm) Acrylic / PC composite: Iupilon film DF02PUL (product name: manufactured by Mitsubishi Gas Chemical Company, thickness 125 μm and 254 μm)

[0065] Preparation of HC films for examples and comparative examples The photocurable resin compositions of Formulation Examples 1 to 7 were used as the HC resin, and the coating was applied to the plastic substrate for evaluation so that the dry film thickness was 3 μm. After drying in a thermostatic chamber at 80°C for 1 minute, the coating was exposed to a high-pressure mercury lamp with an output of 1300 mW / cm. 2 The HC film for evaluation was prepared by irradiating the acrylic / PC composite substrate with ultraviolet light so that the cumulative light amount was 200 mJ. For the acrylic / PC composite substrate, the coating was applied to the PMMA side.

[0066] Table 1 JPEG2026012067000001.jpg68135

[0067] The evaluation method was as follows.

[0068] Transparency: Haze was measured in accordance with JIS K7136 using a haze meter HAZE-GARDi manufactured by Byk-Gardner, with less than 10% being rated as good and 10% or more being rated as bad.

[0069] Abrasion resistance: Using a friction tester FR-IBS manufactured by Suga Test Instruments, the resin composition coated surface of the hard coat film was rubbed with a friction element (diameter 16 mm) equipped with a test white cotton cloth (Kanakin No. 3) under a load of 9 N, and moved back and forth 100 mm at a speed of 1 reciprocation per second. After 100 reciprocations, the presence or absence of scratches was checked, with a circle representing no scratches and an x ​​representing scratches.

[0070] Adhesion: In accordance with the cross-cut method of JIS K 5600-5-6, a 10 x 10 grid was created on the coated surface at 1 mm intervals, and cellophane tape CT-24 (trade name: manufactured by Nichiban Co., Ltd.) was applied and pulled upward to check for peeling, with a ◯ indicating no peeling and an × indicating peeling. No peeling: 100 / 100, Peeling: 0 / 100~99 / 100

[0071] Tensile elongation at break: The HC film was cut into a size of 25 mm wide x 110 mm long, and a tensile test was performed using a TechnoGraph TGI-1KN manufactured by Minebea Co., Ltd., with a chuck distance of 50 mm, an atmospheric temperature of 130°C, and a pulling rate of 300 mm / min. Cracks in the HC layer were visually confirmed, and the elongation was evaluated as follows: less than 50% was evaluated as ×, 50% to 100% as ○, and more than 100% as ◎. Calculation formula: Calculate how many mm it has stretched based on 50 mm. Stretched length (mm) / 50mm x 100 = stretch rate %

[0072] Molding temperature: Using a TOM molding machine NGF-T-0203 manufactured by Fuse Vacuum Co., Ltd., the hard-coated film was heated and then vacuum-pressure molded using a cylindrical mold with a diameter of 30 mm and height of 20 mm at a pressure of 300 kPa for 15 seconds. The temperature at which the film could be completely molded was defined as the molding temperature for that film. Evaluation was based on the following criteria: less than 125°C: ◎; 125-150°C: 〇; and over 150°C or unmoldable: ×.

[0073] Flexibility: Using a BYK-Gardner cylindrical mandrel tester CAT-No. 5710, a test film sample of 120mm x 30mm was bent 180 degrees and the diameter at which no cracks occurred was measured. The evaluation method was as follows: with the HC surface facing outward (folded outward), if the R was 4mm or less it was rated as good, if it was 5mm to 7mm it was rated as fair, and if it was 8mm or more it was rated as bad.

[0074] Example evaluation results Table 2 JPEG2026012067000002.jpg89135

[0075] Comparative Example Evaluation Results Table 3 JPEG2026012067000003.jpg79135

[0076] The examples were satisfactory in all respects, including transparency, abrasion resistance, adhesion, tensile elongation at break, molding temperature, and flexibility.

[0077] On the other hand, Comparative Example 1, which used a binder with low elongation at break, had poor moldability and low flexibility, and Comparative Example 2, which used a polypropylene base material containing a nucleating agent, had poor transparency. Furthermore, Comparative Examples 3 to 7, which used base materials other than polypropylene, were poor in any of tensile elongation at break, molding temperature, and flexibility, and were not suitable for the present invention.

Claims

1. A hard coat film having a cured layer of a photocurable resin composition on a polypropylene substrate, wherein the hard coat film has a tensile elongation at break of 50 to 400% at 130°C, and the polypropylene substrate does not contain a nucleating agent.

2. 2. The hard coat film according to claim 1, wherein the photocurable resin composition contains a polyfunctional urethane (meth)acrylate.

3. 2. The hard coat film according to claim 1, wherein the hard coat film has a moldable temperature of 125° C. or lower when vacuum-pressure molded using a cylindrical mold having a diameter of 30 mm and a height of 20 mm.

4. A method for producing an insert-molded article, comprising shaping the hard coat film according to any one of claims 1 to 3 using a mold, and then injecting a molten resin from the side opposite to the photocurable resin cured layer to form a resin molded article.

5. An insert-molded or out-molded product using the hard coat film according to any one of claims 1 to 3.

6. A molded film comprising the hard coat film according to any one of claims 1 to 3, further comprising a decorative layer and / or a pressure-sensitive adhesive layer.

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