Film for molding

Abstract

To provide a film for molding having excellent moldability as well as scratch resistance and nail scratch resistance and capable of being used in film molding such as insert molding and out-mold molding.SOLUTION: A film for molding has a surface protective layer on a substrate, wherein the film for molding is characterized by that the surface protective layer includes an acrylic copolymer containing a nonreactive siloxane skeleton, a thickness of the surface protective layer is 30 to 250 nm, and the substrate is a composite substrate of an acrylic resin and a polycarbonate resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a molding film used when producing a decorated molded product by a film molding method. [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. This method is widely adopted because it allows for greater design freedom compared to methods using paint such as spray painting, makes it easy to decorate surfaces with three-dimensional irregularities, and is also highly productive. For example, a well-known method is insert molding, in which a pattern is printed on the film surface, which is then heated to soften it and then three-dimensionally molded, and then set in a mold for injection molding.

[0004] Molded films used in insert molding typically have a hard coat layer to improve surface hardness and scratch resistance. However, if the hard coat resin layer is 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 for insert molding, which contains a triazine ring-containing (meth)acrylate prepolymer and organic fine particles with an average primary particle diameter of 80 to 500 nm (Patent Document 1). This hard coat agent was excellent, achieving both sufficient flexibility and surface properties at a film thickness of 1 to 10 μm.

[0005] By selecting a hard coating agent suited to these molding applications, processing constraints have been alleviated to some extent. However, as the applications of insert molding products have expanded in recent years, there has been a demand for greater moldability. In particular, in the case of automotive parts that are decorated with paint, deep drawing is often required, and it has become difficult to achieve this with hard coating films, which require coating thicknesses on the order of microns. Therefore, there is a demand for molding films that offer better moldability and can serve as a paint replacement. [Prior art documents] [Patent documents]

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

[0007] An object of the present invention is to provide a molding film that can be used in film molding, which has excellent formability as well as excellent scratch resistance and scratch resistance with fingernails. [Means for solving the problem]

[0008] In order to solve the above problems, the invention of claim 1 provides a molding film having a surface protective layer on a substrate, wherein the surface protective layer contains a non-reactive siloxane skeleton-containing acrylic copolymer (A), the thickness of the surface protective layer is 30 to 250 nm, and the substrate is a composite substrate of an acrylic resin and a polycarbonate resin.

[0009] The invention of claim 2 provides the molding film according to claim 1, characterized in that (A) is an acrylic copolymer having a siloxane skeleton in the side chain.

[0010] The invention of claim 3 provides the molding film according to claim 1, characterized in that the surface protective layer further contains an acrylic (meth)acrylate (B) having a plurality of (meth)acryloyl groups and a siloxane skeleton in the side chain of the acrylic main chain.

[0011] The invention of claim 4 provides a method for producing an insert-molded product, in which the molding 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 surface protection layer to form a resin molded product.

[0012] The invention of claim 5 provides an insert molded product or an out-molded product using the molding film of any one of claims 1 to 3. [Effects of the Invention]

[0013] The film of the present invention has good formability and excellent scratch resistance and scratch resistance by fingernails, and is therefore useful as a molding film that can be used in insert molding or out-molding as an alternative to painting. BEST MODE FOR CARRYING OUT THE INVENTION

[0014] The molding film has a composite substrate of acrylic resin and polycarbonate resin and a coating layer of a resin composition (hereinafter referred to as the composition) containing a siloxane skeleton-containing acrylic copolymer (A). In this specification, (meth)acrylate includes both acrylate and methacrylate.

[0015] The substrate used in the present invention is a composite substrate of an acrylic substrate having high transparency and hardness and a polycarbonate (hereinafter referred to as PC) substrate having excellent impact resistance and high heat resistance. Here, the composite substrate of an acrylic substrate and a PC substrate (hereinafter referred to as the present composite substrate) means a resin laminate having a PC resin layer on at least one side of an acrylic resin layer. The method for laminating the acrylic resin and the PC resin is preferably co-extrusion molding.

[0016] The thickness of the composite substrate is preferably 80 to 500 μm, more preferably 100 to 400 μm, and particularly preferably 125 to 300 μm. A thickness of 80 μm or more ensures sufficient moldability and deep drawability, while a thickness of 500 μm or less ensures sufficient moldability and optical properties.

[0017] In order to improve adhesion to the composition, the composite substrate may be subjected to a surface treatment such as a primer treatment, sandblasting, or solvent treatment to create a rough surface, or a surface oxidation treatment such as corona discharge treatment, chromic acid treatment, or ozone / ultraviolet irradiation treatment.

[0018] The siloxane skeleton-containing acrylic copolymer (A) used in this composition is a non-reactive copolymer that does not contain reactive functional groups such as acryloyl or vinyl groups. For example, an acrylic copolymer with a siloxane skeleton in the side chain of the acrylic main chain can be used. Because it does not contain urethane bonds in the molecular skeleton like urethane acrylates, the resin itself is a binder with excellent weather resistance. Furthermore, a tack-free surface can be achieved simply by evaporating the solvent.

[0019] The weight average molecular weight (hereinafter referred to as Mw) of (A) is preferably 10,000 to 100,000, more preferably 20,000 to 80,000, and particularly preferably 30,000 to 60,000. By setting it to 10,000 or more, a sufficient elongation rate can be ensured, and by setting it to 100,000 or less, sufficient drying properties can be ensured and it is easy to adjust the viscosity to one that is easy to work with.

[0020] The blending amount of (A) is preferably 30 to 100% by weight, more preferably 40 to 95% by weight, and particularly preferably 60 to 90% by weight, based on the total solid content. By making it 30% by weight or more, sufficient scratch resistance can be ensured.

[0021] The composition preferably further contains an acrylic (meth)acrylate (B) having a plurality of (meth)acryloyl groups and a siloxane skeleton in the side chain of the acrylic main chain. By incorporating (B), the lubricity of the cured product surface can be improved, and scratch resistance by fingernails can be significantly improved.

[0022] The Mw of (B) is preferably 3,000 to 50,000, more preferably 5,000 to 30,000. By setting it within this range, sufficient abrasion resistance can be ensured. The double bond equivalent is preferably 100 to 1,000 g / mol, more preferably 150 to 700 g / mol. By setting it within this range, sufficient reactivity and scratch resistance can be ensured.

[0023] The blending amount of (B) is preferably 0 to 65% by weight, more preferably 5 to 60% by weight, based on the total solid content. By setting the blending amount to 65% by weight or less, sufficient scratch resistance can be ensured. Commercially available products of (B) include 8SS-723 (trade name: manufactured by Taisei Fine Chemical Co., Ltd., double bond equivalent weight 340 g / mol, Mw 10,000).

[0024] When the composition contains a photocurable reactive monomer, it is preferable to incorporate a photopolymerization initiator (C). (C) generates radicals when irradiated with ultraviolet light or an electron beam, 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.

[0025] Among these, it is preferable to use an α-hydroxyacetophenone-based compound, which is less susceptible to yellowing. Furthermore, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one is even more preferable, as it is less susceptible to polymerization inhibition by oxygen and has excellent surface curing properties. Examples of commercially available products include Omnirad 127D (trade name: manufactured by IGM Resins, α-hydroxyacetophenone-based compound). The blending amount of the aforementioned (C) per 100 parts by weight of the radically polymerizable component is preferably 5 to 50 parts by weight, more preferably 10 to 20 parts by weight.

[0026] To the present composition, reactive monomers, antioxidants, bluing agents, leveling agents, antifoaming agents, thickeners, antistatic agents, antifogging agents, antibacterial agents, matting agents, inorganic fine particles, organic fine particles, and the like may be added as needed, provided that the performance is not impaired.

[0027] When applying the composition to the composite 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. Among these, butyl acetate is preferred due to its compatibility with (A). The solids content of the diluted solution is typically 3 to 50%, but there are no specific restrictions and the viscosity can be adjusted appropriately to achieve a coating viscosity that is easy to apply.

[0028] The thickness of the surface protective layer coated with the composition is 30 to 250 nm, preferably 50 to 200 nm, more preferably 70 to 150 nm, and particularly preferably 80 to 125 nm. If the thickness is less than 30 nm, the scratch resistance and scratch resistance with fingernails tend to decrease, and if the thickness exceeds 250 nm, the scratch resistance also tends to decrease.

[0029] The method for applying the present composition is not particularly limited, and the composition can be formed by a known coating method such as spray coating, roll coating, die coating, air knife coating, blade coating, spin coating, reverse coating, gravure coating, or wire bar coating, or a printing method such as gravure printing, screen printing, offset printing, or inkjet printing.

[0030] When the composition does not contain a photocurable reactive monomer component, it is preferable to dry it by heat. The drying temperature is preferably 50 to 120°C, more preferably 60 to 100°C, and particularly preferably 70 to 90°C. The drying time may be appropriately set depending on the drying temperature, the amount and type of solvent contained, the coating amount, etc., and is, for example, 30 to 180 seconds, but is not limited thereto.

[0031] When the composition contains a photocurable reactive monomer component, it is preferable to cure the composition by ultraviolet irradiation after drying the solvent, etc. Examples of ultraviolet light sources used for curing include 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 ultraviolet lamps. 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.

[0032] When curing by UV irradiation, it is preferable to use an inert gas atmosphere such as nitrogen or argon to avoid polymerization inhibition by oxygen. In addition, by heating the back roll or the coating film with an IR heater during UV irradiation, the curing property can be further improved.

[0033] A decorative layer can be provided on the present molding film as needed. Examples of decorative methods include printing and metal vapor deposition, and both methods may be used for decoration. Furthermore, an adhesive layer or a primer layer may be provided to improve adhesion with the injection molding resin. The decorative surface may be between the surface protective layer and the composite substrate, or / and on the opposite side of the surface to which the surface protective layer is applied.

[0034] A protective film may be attached to this molding film to protect the surface protective layer. Using a protective film can prevent scratches during insert molding or out-molding processes, and is expected to improve yield.

[0035] A method of using this molding film in insert molding is, for example, to position the surface of the surface protection layer facing the inner wall surface of the mold (so that the opposite side of the surface protection layer is in contact with the molding resin), and if necessary, to pre-mold this molding film to conform to the shape of the mold, and then close the mold and inject molten molding resin into the cavity, allowing the resin to solidify, thereby forming a resin molded product.

[0036] The preforming method may be a method in which the 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, press molding, etc., using a molding mold separate from the injection molding mold. It is also possible to perform molding and integral molding of the injected resin simultaneously by the injection pressure of the molding resin without performing these preforming methods.

[0037] Furthermore, this molding 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 molded in an airtight box and three-dimensional surface decoration is performed using vacuum and pressure molding, and it can also be used for large three-dimensional products.

[0038] 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 in terms of solid matter.

[0039] Examples and Comparative Examples A siloxane skeleton-containing acrylic copolymer (structure: acrylic copolymer having a siloxane skeleton in the side chain, Mw 40,000) was used as (A), 8SS-723 (trade name: manufactured by Taisei Fine Chemical Co., Ltd., double bond equivalent 340 g / mol, Mw 10,000, solids content 35%) was used as (B), and Omnirad127D (trade name: manufactured by IGM Resins, α-hydroxyacetophenone-based) was used as (C) in the formulations shown in Tables 1 and 2. These were stirred until uniformly dissolved and dispersed, and then butyl acetate was added to the mixture to adjust the solids content to 2.5%, followed by dilution and stirring to obtain the present compositions of the examples and comparative examples.

[0040] Table 1 JPEG2025135762000001.jpg75135

[0041] Table 2 JPEG2025135762000002.jpg86135

[0042] The evaluation method was as follows.

[0043] Preparation of molding film Using the resin compositions prepared in the examples and comparative examples, protective films were formed with the listed film thicknesses on the substrates listed in Tables 1 and 2 to produce molding films. The composite substrate was DF02PU (trade name: manufactured by Mitsubishi Gas Chemical Company, Inc., thickness 125 μm), and the PET substrate was U403 (trade name: manufactured by Toray Industries, Inc., thickness 125 μm). In the case of the composite substrate, the resin composition was applied to the acrylic side. The drying conditions were 80°C x 1 minute in a thermostatic oven, and the ultraviolet irradiation conditions were a high-pressure mercury lamp with an output of 1300 mW / cm2 (in a nitrogen atmosphere) and an integrated light intensity of 200 mJ.

[0044] Total light transmittance: Measured in accordance with JIS K7361-1 using a haze meter Haze-GARD2 manufactured by Toyo Seiki Seisakusho Co., Ltd. The evaluation method was as follows: 90% or more was rated as good, and less than 90% was rated as bad.

[0045] Haze: Measured in accordance with JIS K7136 using a haze meter Haze-GARD2 manufactured by Toyo Seiki Seisakusho, Ltd. The evaluation method was as follows: less than 1% was rated as good, and 1% or more was rated as bad.

[0046] Scratch resistance: Using an abrasion tester manufactured by Toyo Seiki Seisakusho, a 500g load was placed on steel wool #0000 with a contact area of ​​4cm2, and the test was repeated 10 times at a reciprocating speed of 100 times per minute. The haze before and after the test was then measured in accordance with JIS K7136 using a Toyo Seiki Haze-GARD2. A haze increase of 2% or less was evaluated as good, and an increase of more than 2% was evaluated as bad.

[0047] Vacuum formability: Using a vacuum forming machine, Forming 300X, manufactured by Seiko Sangyo Co., Ltd., the formed film was heated to a substrate temperature of 190°C, and then vacuum formed using a square mold 30 mm in diameter x 30 mm in height. The depth (H) at which the film could be completely formed without whitening or cracking was measured. Evaluation was given for more than 30 mm as ◯, and less than 30 mm as ×.

[0048] Fingernail scratch resistance (slipperiness): The coated surface was scratched with a fingernail and visually inspected for scratches. If the fingernail did not catch and the surface slid, it was marked with an ⊚, if no scratches were observed, it was marked with an ◯, and if scratches were observed, it was marked with an ×.

[0049] Example evaluation results Table 3 JPEG2025135762000003.jpg101130

[0050] Table 4 JPEG2025135762000004.jpg147164

[0051] The examples were satisfactory in all respects, including total light transmittance, haze, scratch resistance, vacuum formability, and scratch resistance with fingernails.

[0052] On the other hand, Comparative Example 1, which did not contain (A), was poor in abrasion resistance and vacuum formability, and Comparative Example 2, which had a thin protective layer, was poor in abrasion resistance and scratch resistance with a fingernail. Furthermore, Comparative Example 3, which had a thick protective layer, was poor in abrasion resistance, and Comparative Example 4, which used a PET substrate, was poor in abrasion resistance and vacuum formability, and neither was suitable for the present invention.

Claims

1. A molding film having a surface protective layer on a substrate, the surface protective layer comprising a non-reactive siloxane skeleton-containing acrylic copolymer (A), the thickness of the surface protective layer being 30 to 250 nm, and the substrate being a composite substrate of an acrylic resin and a polycarbonate resin.

2. 2. The molding film according to claim 1, wherein the component (A) is an acrylic copolymer having a siloxane skeleton in the side chain.

3. 2. The molding film according to claim 1, wherein the surface protective layer further contains an acrylic (meth)acrylate (B) having a plurality of (meth)acryloyl groups and a siloxane skeleton in the side chain of the acrylic main chain.

4. A method for producing an insert-molded article, comprising shaping the molding 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 surface protective layer to form a resin molded article.

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

Images