Vinylidene fluoride resin film
阅读说明：本技术 偏二氟乙烯系树脂膜 (Vinylidene fluoride resin film ) 是由 永冈洪太 泽里正 高野敬司 于 2018-05-31 设计创作，主要内容包括：本发明提供一种偏二氟乙烯系树脂膜,其虽然是光泽度低的哑光色调,但雾度低,下层的装饰膜的图案等的视觉辨认性高。偏二氟乙烯系树脂膜,其是含有交联丙烯酸酯系树脂粒子的偏二氟乙烯系树脂膜,前述交联丙烯酸酯系树脂粒子具有相对于前述偏二氟乙烯系树脂膜的厚度而言为5％以上且40％以下的平均粒径,前述偏二氟乙烯系树脂膜的算术平均表面粗糙度(Ra)为0.4μm以上且小于2μm。(The invention provides a vinylidene fluoride resin film which has low haze and high visibility of patterns and the like of a decorative film of a lower layer, although having a matte color tone with low glossiness. A vinylidene fluoride resin film comprising crosslinked acrylate resin particles, wherein the crosslinked acrylate resin particles have an average particle diameter of 5% or more and 40% or less relative to the thickness of the vinylidene fluoride resin film, and the arithmetic average surface roughness (Ra) of the vinylidene fluoride resin film is 0.4 [ mu ] m or more and less than 2 [ mu ] m.)
1. A vinylidene fluoride resin film containing crosslinked acrylate resin particles,
the crosslinked acrylate resin particles have an average particle diameter of 5% or more and 40% or less with respect to the thickness of the vinylidene fluoride resin film,
the vinylidene fluoride resin film has an arithmetic average surface roughness (Ra) of 0.4 [ mu ] m or more and less than 2 [ mu ] m.
2. The vinylidene fluoride-based resin film according to claim 1, wherein the crosslinked acrylate-based resin particles are contained in an amount of 5 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the vinylidene fluoride-based resin.
3. The vinylidene fluoride-based resin film according to claim 1 or 2, wherein the crosslinked acrylate-based resin particles have an average particle diameter of 3.5 μm or more and 7.5 μm or less.
4. The vinylidene fluoride-based resin film according to any one of claims 1 to 3, wherein the vinylidene fluoride-based resin contains a copolymer of vinylidene fluoride and hexafluoropropylene and/or polyvinylidene fluoride.
5. The vinylidene fluoride-based resin film according to any one of claims 1 to 4, wherein the vinylidene fluoride-based resin contains a methacrylate-based resin.
6. The vinylidene fluoride-based resin film according to any one of claims 1 to 5, wherein the vinylidene fluoride-based resin contains, in total, 100 parts by mass:
a vinylidene fluoride resin containing a copolymer of vinylidene fluoride and hexafluoropropylene and/or polyvinylidene fluoride in an amount of 50 to 99 parts by mass, and
the amount of the methacrylate resin is 50 parts by mass or less and 1 part by mass or more.
7. The vinylidene fluoride-based resin film according to any one of claims 1 to 6, wherein the thickness of the vinylidene fluoride-based resin film is 5 μm or more and 200 μm or less.
8. A laminated film in which the vinylidene fluoride resin film according to any one of claims 1 to 7 is laminated on a methacrylate resin film.
9. The laminate film according to claim 8, wherein the methacrylate-based resin contains a vinylidene fluoride-based resin.
10. The laminate film according to claim 8 or 9, wherein the methacrylate-based resin contains, in total, 100 parts by mass:
a vinylidene fluoride resin containing a copolymer of vinylidene fluoride and hexafluoropropylene and/or polyvinylidene fluoride in an amount of 50 parts by mass or less and 1 part by mass or more, and
the amount of the methacrylate resin is 50 to 99 parts by mass.
11. The laminate film according to any one of claims 8 to 10, wherein the thickness of the entire laminate film is 20 μm or more and 300 μm or less, and the ratio of the methacrylate resin film to the thickness of the entire film is 95% or less.
12. The laminated film according to any one of claims 8 to 11, which is laminated to a decorative film.
13. An automobile or an automobile part, wherein the vinylidene fluoride resin film according to any one of claims 1 to 7 or the laminate film according to any one of claims 8 to 12 is bonded to a surface thereof.
Technical Field
The present invention relates to a vinylidene fluoride resin film.
Background
In the field of automobile decoration, painting and metal plating have been used for a long time, but in recent years, there has been a movement to turn to film decoration without painting and metal plating for the purpose of reducing the weight of a vehicle body and reducing production line processes.
For example, the following operations have been performed: the body, panel, and the like of an automobile are decorated with a decorative film and further covered with a protective layer.
The outermost layer of the decorative film protective layer used in the past is an acrylic film. However, acrylic films have some disadvantages, for example, the following are present: the acrylic film is deteriorated by the action of the sunscreen and the insect repellent, and when the temperature rises in a state where the sunscreen and the insect repellent are adhered, the acrylic film is whitened.
In addition, the decorative film protective layer is required to have a concave-convex following property that allows the film to adhere to a vehicle body, a panel control panel, or the like having a large number of concave-convex portions and a complicated shape even when the number of concave-convex portions is large.
Further, for exterior decoration of automobiles and the like, non-metallic-tone decoration has started to be popular. The non-metallic color tone is a matte color tone with low glossiness, and is also called a matte color tone, and is often used for high-grade vehicles and the like.
For example, as a film having a matte color tone for an automobile member, a vinylidene fluoride resin film described in
Disclosure of Invention
Problems to be solved by the invention
However, the vinylidene fluoride resin film described in
Therefore, the following inverse characteristics are required for the protective film: the matte color tone has low glossiness, but has low haze, excellent visible light transmittance, and good visibility of patterns and the like on the decorative film. Further, chemical resistance, weather resistance, heat resistance, unevenness follow-up property, and the like are also required.
Means for solving the problems
Accordingly, the present inventors have made intensive studies to solve the above problems, and have completed the present invention.
Namely, the present invention provides:
a vinylidene fluoride resin film containing crosslinked acrylate resin particles,
the crosslinked acrylate resin particles have an average particle diameter of 5% or more and 40% or less relative to the thickness of the vinylidene fluoride resin film,
the vinylidene fluoride resin film has an arithmetic average surface roughness (Ra) of 0.4 μm or more and less than 2 μm.
Here, it is preferable that the crosslinked acrylate resin particles are contained in an amount of 5 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the vinylidene fluoride resin.
Further, the crosslinked acrylate resin particles preferably have an average particle diameter of 3.5 μm or more and 7.5 μm or less.
Preferably, the vinylidene fluoride resin contains a copolymer of vinylidene fluoride and hexafluoropropylene and/or polyvinylidene fluoride.
The vinylidene fluoride resin may contain a methacrylic acid ester resin.
In this case, it is preferable that the vinylidene fluoride resin contains, in total, 100 parts by mass:
a vinylidene fluoride resin containing the copolymer of vinylidene fluoride and hexafluoropropylene and/or polyvinylidene fluoride in an amount of 50 to 99 parts by mass, and
the methacrylate resin is 50 parts by mass or less and 1 part by mass or more.
The thickness of the vinylidene fluoride resin film of the present invention can be set to 5 μm or more and 200 μm or less.
The vinylidene fluoride resin film of the present invention may be formed as a laminated film laminated on a methacrylic ester resin film.
The methacrylate resin may contain a vinylidene fluoride resin.
In this case, it is preferable that the methacrylate-based resin contains, in total, 100 parts by mass:
a vinylidene fluoride resin containing the copolymer of vinylidene fluoride and hexafluoropropylene and/or polyvinylidene fluoride in an amount of 50 parts by mass or less and 1 part by mass or more, and
the methacrylate resin is 50 to 99 parts by mass.
Preferably, the thickness of the entire laminated film is 20 μm or more and 300 μm or less, and the ratio of the methacrylate resin film to the entire film is 95% or less.
Further, the aforementioned laminated film may be laminated to a decorative film.
Further, the present invention can provide an automobile or an automobile part, wherein the vinylidene fluoride resin film or the laminate film is bonded to a surface thereof.
ADVANTAGEOUS EFFECTS OF INVENTION
The present invention provides a vinylidene fluoride resin film having low haze and excellent visible light transmittance, despite having a matte color tone with low gloss, and having high visibility of a pattern or the like of an underlying decorative film. Further, a vinylidene fluoride resin film excellent in chemical resistance, weather resistance, heat resistance, unevenness following property, adhesion to other substrates, etc. and also excellent in workability can be provided.
Drawings
FIG. 1 is a view showing a vinylidene fluoride resin film of the present invention.
FIG. 2 is a view showing a vinylidene fluoride resin film of the present invention.
FIG. 3 is a view showing a laminated film of the present invention.
Detailed Description
Preferred embodiments for carrying out the present invention will be described below. The embodiments described below are representative embodiments of the present invention, but the scope of the present invention is not to be construed as being limited thereto.
[ 1] vinylidene fluoride resin film of the present invention ]
The vinylidene fluoride resin film of the present invention contains crosslinked acrylate resin particles.
1-1 vinylidene fluoride resin
First, the vinylidene fluoride resin serving as a base material of the vinylidene fluoride resin film preferably has a refractive index close to that of a crosslinked acrylate resin to be described later which is blended in the form of particles. The refractive index is preferably 1.3 to 1.5, and more preferably 1.4 to 1.49.
When the refractive index is 1.3 to 1.5, the difference in refractive index between the crosslinked acrylate resin and the crosslinked acrylate resin is not excessively large, and the increase in internal haze can be suppressed, and the visibility of a pattern or the like on a film protection object such as an automobile part can be favorably maintained.
The vinylidene fluoride resin having the above refractive index is not particularly limited, and examples thereof include polyvinylidene fluoride and a copolymer of vinylidene fluoride and hexafluoropropylene. These resins may be used alone or in combination as necessary. In particular, by using a copolymer of vinylidene fluoride and hexafluoropropylene, the concave-convex following property becomes good.
The vinylidene fluoride resin can be used by mixing with other resins as needed within a range that does not impair the weather resistance, chemical resistance, stain resistance, and transparency, which are the characteristics of the vinylidene fluoride resin, and that maintains the above-mentioned refractive index.
As a preferable example, there is a mixture of a vinylidene fluoride resin and a methacrylate resin. From the viewpoint of compatibility, a methacrylate-based resin is also preferable.
The mixing ratio of the vinylidene fluoride resin and the methacrylate resin is not particularly limited as long as it is within a range that does not deteriorate the internal haze value of the film, and preferable mixing ratios are set so that the total amount becomes 100 parts by mass, for example:
a vinylidene fluoride resin containing a copolymer of vinylidene fluoride and hexafluoropropylene and/or polyvinylidene fluoride in an amount of 50 to 99 parts by mass, and
the methacrylate resin is 50 parts by mass or less and 1 part by mass or more.
When the mixing ratio is set within the above range, a film rich in a vinylidene fluoride resin is obtained, and the chemical resistance, weather resistance, heat resistance, unevenness-following property, adhesion to other substrates, and the like are improved.
When the vinylidene fluoride resin is 50 parts by mass or more, the characteristic antifouling property of the vinylidene fluoride resin can be sufficiently obtained.
Further, when the methacrylate resin is 50 parts by mass or less, the strength of the film can be maintained, and the film can be prevented from being broken even when a tension is applied during processing such as lamination.
Examples of the methacrylate-based resin include polymethyl methacrylate, a copolymer of methyl methacrylate and n-butyl acrylate, a copolymer with another monomer, n-butyl acrylate rubber-reinforced methyl methacrylate, and the like. These may be used alone or in combination of two or more, as required.
The methacrylate-based resin is not particularly limited in kind and amount as long as transparency in the case of being mixed with the vinylidene fluoride-based resin is not impaired.
In the vinylidene fluoride resin film of the present invention, a heat stabilizer may be added as necessary in addition to the above-mentioned methacrylate resin. Examples of the heat stabilizer include phenol antioxidants, phosphorus antioxidants, sulfur antioxidants, epoxy compounds, and β -diketones. Among them, the phenol-based antioxidant and the phosphorus-based antioxidant are preferable because transparency is not inhibited.
The heat stabilizer may be added by using as a raw material a product obtained by melt-mixing and granulating a vinylidene fluoride resin and/or a methacrylate resin in advance, or by melt-mixing the components at the time of producing a film and then molding the film from the liquid stream.
The amount of the heat stabilizer to be added is not particularly limited, but is preferably 0.001 to 5% by mass, more preferably 0.1 to 1.0% by mass.
When the content is 0.001% by mass or more, sufficient thermal stability can be obtained, and when the content is 5% by mass or less, deterioration in transparency of the vinylidene fluoride resin film, visibility of the decorative film (substrate), and color tone can be suppressed.
Further, an ultraviolet absorber may be added to the vinylidene fluoride resin film as necessary. Examples of the ultraviolet absorber include organic ultraviolet absorbers such as benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, and triazine ultraviolet absorbers.
Particularly preferred is a triazine-based ultraviolet absorber, and from the viewpoint of compatibility with a vinylidene fluoride-based resin, 2- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) -5- [2- (2-ethylhexanoyloxy) ethoxy ] phenol is preferred.
The ultraviolet absorber may be added by a method in which a product obtained by melt-mixing and granulating a vinylidene fluoride resin and/or a methacrylate resin in advance is used as a raw material, or by a method in which the components are melt-mixed at the time of film production and then film-molding is performed by using a liquid stream thereof.
The amount of the ultraviolet absorber added is not particularly limited, but is preferably 0.001 to 10% by mass, more preferably 0.1 to 5% by mass.
When the amount is 0.001% by mass or more, sufficient ultraviolet blocking performance can be obtained, and the adherend of the vinylidene fluoride resin film of the present invention can be protected from ultraviolet deterioration. When the content is 10% by mass or less, deterioration of transparency, visibility of a decorative film (substrate) and color tone of the vinylidene fluoride resin film can be suppressed.
Further, a plasticizer, a lubricant, an antistatic agent, an antifogging agent, a dripping agent, a hydrophilic agent, a lyophobic agent, and the like may be added within a range of low glossiness, transparency, heat resistance, practically no damage to the appearance of the film, and the like. The pigment may be added, but in the case of a titanium pigment or the like, the pigment may not be added because it may have a white color tone.
As the method of addition, in addition to the method of addition at the time of melt mixing as described above, the surface may be coated after the film is produced.
As described above, the composition of the vinylidene fluoride resin film as the base material containing the crosslinked acrylate resin particles is constituted.
1-2 Cross-Linked acrylate resin particles
The crosslinked acrylate resin particles usable in the vinylidene fluoride resin film of the present invention are obtained, for example, from acrylic acid esters such as methyl methacrylate and n-butyl methacrylate.
The crosslinking agent is not particularly limited, and as a general crosslinking agent, an epoxy crosslinking agent, an isocyanate crosslinking agent, or the like can be used.
The particle diameter of the crosslinked acrylate resin particles is 5 to 40% of the average particle diameter of the vinylidene fluoride resin film of the present invention, preferably 10 to 35%.
For example, the vinylidene fluoride resin film has an average particle diameter of 0.25 to 80 μm when the thickness is 5 to 200. mu.m.
When the average particle size is less than 0.25 μm, the light scattering efficiency is increased due to the large number of particles, and the internal haze of the film becomes excessively high, compared with a film containing the same amount of particles having a larger average particle size.
When the average particle diameter is larger than 80 μm, the number of particles is small, and thus the unevenness on the film surface is reduced, and the light scattering efficiency is lowered, as compared with a film to which the same amount of particles having a smaller average particle diameter are added. As a result, the external haze becomes too low, the gloss of the film surface increases, and matte feeling is not easily obtained, which is not preferable.
When the vinylidene fluoride-based resin film of the present invention is used as a surface protective film for a vehicle body, a member or the like of an automobile, the average particle diameter of the crosslinked acrylate-based resin particles is preferably 3.5 to 7.5 μm, more preferably 3.5 to 4.5 μm.
It is generally considered that when the average particle diameter is small, the surface gloss increases and a matte surface cannot be obtained. However, in the present invention, particles having a small average particle diameter, which are considered to be difficult to obtain a matte surface, are used. Unexpectedly, a membrane is thus obtained which simultaneously achieves the following effects: the film has a matte effect, a low haze, excellent visible light transmittance, and high visibility of a pattern or the like of the lower decorative film.
However, when the average particle diameter is too small, the internal haze of the film increases, and the film becomes white, which is not preferable.
The crosslinked acrylate resin particles may contain particles having the same average particle size in the vinylidene fluoride resin film, or may contain particles having different average particle sizes in the vinylidene fluoride resin film by mixing them.
1-3 vinylidene fluoride resin film containing crosslinked acrylate resin particles
The crosslinked acrylate resin particles are preferably contained in an amount of 5 to 25 parts by mass with respect to 100 parts by mass of the vinylidene fluoride resin. When the amount is 25 parts by mass or less, the internal haze is not excessively high, and the visibility of the object to be protected can be maintained. When the amount is 5 parts by mass or more, the external haze is not excessively low, and the increase in gloss can be suppressed, so that the matte feeling on the film surface can be maintained.
In particular, when the resin composition is used for a vinylidene fluoride resin film for automobile bodies or parts, the content of the crosslinked acrylate resin particles is preferably 8 to 12 parts by mass per 100 parts by mass of the vinylidene fluoride resin, but the resin composition is not limited thereto.
Fig. 1 shows an embodiment of a vinylidene fluoride resin film of the present invention.
The crosslinked
Here, the arithmetic average surface roughness (Ra) of the matte-
When the arithmetic average surface roughness (Ra) is less than 0.4. mu.m, the haze of the film is reduced and gloss appears. When the arithmetic average surface roughness (Ra) is 2 μm or more, the haze of the film increases, and the film has a rougher impression than a matte color tone, and the transparency and the visibility are also reduced.
The
The thickness of the vinylidene fluoride resin film includes a height of an arithmetic average surface roughness (Ra) of the vinylidene fluoride resin film.
1-4. method for producing vinylidene fluoride resin film
The method for producing the vinylidene fluoride resin film of the present invention is not particularly limited, and conventional techniques may be applied thereto.
The raw materials used in the vinylidene fluoride resin film were previously uniformly melt-mixed and used for film production.
The extruder to be melt-mixed in advance is not particularly limited, and may be any extruder having a screw length and a screw structure sufficient for melting and uniformly dispersing the resin raw material. Examples of the melt-kneading that can be uniformly carried out include a twin-screw extruder having a screw structure with a sufficient kneading function such as kneading with a normal screw and kneading with a neutral screw and a reverse screw.
The vinylidene fluoride resin film can be produced by any of a solvent casting method and an extrusion molding method, and the extrusion molding method is preferably applied from the viewpoint of improving the production efficiency.
Examples of the apparatus used for extrusion molding include an apparatus having a T die downstream of a single-screw or twin-screw extruder.
When the fluororesin is heated more than necessary, a harmful gas may be generated due to decomposition of the resin, and therefore, a single-screw extruder is more preferable in order to prevent excessive shear heat generation and reduce the staying portion.
As a preferable specification of a screw for an extruder, a ratio (L/D) of a screw length (L [ mm ]) to a screw diameter (D [ mm ]) is preferably 20 to 40. When the L/D is less than 20, plasticization and melting of the resin used as a raw material become insufficient, and appearance defects and transparency are likely to be deteriorated due to mixing of an unmelted material into the film. When the L/D is more than 40, the heating time becomes too long and the resin is easily subjected to excessive shear, so that the resin is easily deteriorated and may be yellowed or foreign matter derived from the deteriorated product may be generated to cause poor appearance.
The preferable compression ratio of the screw is preferably 1.5 to 4.0, and more preferably 2.0 to 3.5. If the amount is less than 1.5, the shear heat generation due to the compression of the space between the cylinder and the screw groove is insufficient, and as a result, the plasticization and melting of the resin used in the raw material become insufficient, and appearance defects and transparency are likely to be deteriorated due to the mixing of an unmelted material into the film, and the extrusion amount and the thickness of the film may be unstable. If the amount exceeds 4.0, the shear heat generation becomes excessive, and therefore, the resin is likely to be deteriorated, and sometimes yellowed, or foreign matter derived from the deteriorated product is generated, resulting in poor appearance.
The structure of the screw is not particularly limited as long as it is a specification that can provide sufficient shear necessary for plasticizing and melting the resin. Typical examples of the configuration include screws having kneading zones with mixing functions of Dalmage, unitt, Maddock types provided for full flight screws, separation screws, and the like.
A screen may be provided downstream of the aforementioned screw in a form fixed to the breaker plate. The screen is preferably a combination of 2 or more screens having different meshes. A mesh with a large mesh is provided upstream for filtering large foreign matter, and a mesh with a small mesh is provided downstream. Further, a net having a large mesh is provided at the downstream portion thereof to prevent the net from being broken by the resin pressure. The mesh of the finest mesh net can be appropriately set according to the purpose and use of the vinylidene fluoride resin film of the present invention, and the allowable range of foreign matter mixed in the film. Preferably less than 0.1mm, more preferably less than 0.05 mm.
The vinylidene fluoride-based resin film of the present invention can be produced by using the above-mentioned apparatus.
1-5 evaluation of vinylidene fluoride resin film
The vinylidene fluoride resin film of the present invention produced can be evaluated by the following items.
Arithmetic mean surface roughness (Ra)
The arithmetic average surface roughness (Ra) of the vinylidene fluoride resin film of the present invention can be measured by a general laser microscope.
As described above, the vinylidene fluoride resin film of the present invention has an arithmetic average surface roughness (Ra) of 0.4 μm or more and less than 2 μm.
Total light transmittance
The total light transmittance of the vinylidene fluoride-based resin film of the present invention was evaluated in accordance with JIS K7361-1.
The measured value with respect to the incident light from the matte tone surface side is preferably 90% or more, and more preferably 91% or more. When the content is less than 90%, the design visibility and sharpness of the decorative film (base) laminated with the vinylidene fluoride resin film tend to be lowered.
Total haze
The total haze of the vinylidene fluoride resin film of the present invention was evaluated according to JIS K7136.
The measured value with respect to the incident light from the matte tone surface side is preferably 60% or more, and more preferably 70% or more. When the amount is less than 60%, the matte or matte feel of the film surface tends to be reduced.
Internal haze
The internal haze in the total haze can be obtained by: the unevenness on the matte surface of the film was filled with liquid paraffin, silicone oil, or the like, and then sandwiched between cover glasses, and measurement was performed in a state where no bubbles were generated.
The internal haze is preferably less than 55%, more preferably less than 45%. When the internal haze is more than 55%, visibility and sharpness of the design of the decorative film (substrate) tend to be reduced.
External haze
The external haze value in the total haze value can be obtained by the difference between the total haze value and the internal haze value.
The external haze is preferably 30% or more, and more preferably 50% or more. When the external haze value is less than 30%, the matte or matte feel of the surface of the vinylidene fluoride resin film tends to be reduced.
Gloss degree
The gloss of the vinylidene fluoride resin film of the present invention was evaluated according to JIS Z8741. It can be measured as the gloss at an incident angle of 60 degrees.
The gloss is preferably less than 15, more preferably less than 12. When the gloss is 15 or more, the matte or matte feel of the surface of the vinylidene fluoride resin film tends to be reduced.
[2. multilayer film of the present invention ]
2-1. composition of back layer
The vinylidene fluoride resin film may be used alone or may be laminated by bonding to another substrate. Lamination is particularly effective when the content of the vinylidene fluoride resin is too high and sufficient adhesion cannot be obtained due to the material of the other substrate.
For example, a back surface layer is provided on the side of the vinylidene fluoride resin film which is not matte in color for the purpose of improving adhesion to other substrates.
Examples of the back layer include a methacrylate resin film. The back layer film may be formed of only a methacrylate resin, or the methacrylate resin may contain a vinylidene fluoride resin.
Examples of the vinylidene fluoride resin include a copolymer of vinylidene fluoride and hexafluoropropylene and/or polyvinylidene fluoride.
When a vinylidene fluoride-hexafluoropropylene copolymer is selected and used for either the front surface layer or the back surface layer or both the front surface layer and the back surface layer, the flexibility of the laminate film can be improved, and the laminate film can be suitably bonded to an adherend having a complicated shape.
The content of the vinylidene fluoride resin in the back layer is not particularly limited, and for example, the following methacrylate resin-rich film may be formed, which contains the following in total 100 parts by mass:
50 parts by mass or less and 1 part by mass or more of a vinylidene fluoride resin, and
the amount of the methacrylate resin is 50 to 99 parts by mass.
When the content of the methacrylate-based resin is 50% by mass or more, sufficient adhesion to other base materials of the decorative film (base) can be obtained, and when the resin is used as a surface protective film for a decorative film, defects due to peeling between the decorative film and the back layer are less likely to occur.
The back surface layer may contain, in addition to the vinylidene fluoride resin, the heat stabilizer, the ultraviolet absorber, the plasticizer, the lubricant, the antistatic agent, the antifogging agent, the drip agent, the hydrophilic agent, the lyophobic agent, and the like, as required. The pigment may be added, but in the case of a titanium pigment or the like, the pigment may not be added because it may have a white color tone.
The addition method may be a method of adding the resin at the time of melt mixing, as in the case of the above-described vinylidene fluoride resin film, or may be a method of applying the resin to the surface after the film is produced.
The heat stabilizer, the ultraviolet absorber, the plasticizer, the lubricant, the antistatic agent, the antifogging agent, the drip agent, the hydrophilic agent, the lyophobic agent, and the like may be added to either the front layer or the back layer, or both the front layer and the back layer.
Addition of the additive to the back layer alone is particularly preferable because appearance defects caused by migration of the additive to the film surface can be prevented.
The thickness of the entire laminated film is not particularly limited as long as the quality required for the use environment can be achieved, and is preferably 20 μm to 300 μm, and more preferably 30 μm to 80 μm.
When the thickness is 20 μm or more, the vinylidene fluoride resin film in the surface layer in the planar direction is less likely to be broken, and the continuity of the vinylidene fluoride resin layer can be maintained. Further, when the thickness is 300 μm or less, the rigidity of the laminate film does not become too high, and the shape-following property to the mold is not impaired when the laminate film is heat-molded into a three-dimensional shape. When a member previously subjected to thermoforming is bonded via an adhesive layer, the ability to follow irregularities of a complicated shape is not impaired.
The thickness of the back layer is not particularly limited, and is preferably 95% or less, and more preferably 90% or less, for example, with respect to the thickness of the entire laminate film.
When the content is 95% or less, the surface layer of the vinylidene fluoride resin film is not excessively thin, and the occurrence of pinholes can be suppressed.
The thickness of the surface layer is preferably 5 to 200. mu.m. In order to prevent the surface layer from being defective in continuity in the planar direction and to prevent the properties of the fluorine-based resin such as chemical resistance and stain resistance from being degraded, the thickness of the surface layer is preferably not excessively smaller than the particle diameter of the crosslinked acrylate-based resin particles.
2-2. method for producing laminated film
When a laminated film of a front layer (a film rich in a vinylidene fluoride resin) and a back layer (a film rich in a methacrylate resin) is produced, the laminated film can be produced by the following method: the raw material for the surface layer was plasticized and melted, and the raw material for the back layer was plasticized and melted independently of the above, and the surface layer and the back layer were merged and laminated in a supply block disposed on the upstream side of the T-die (i.e., on the downstream side of the extruder) using an extruder (extruder a) for producing the surface layer and an extruder (extruder B) for the back layer, and the mixture was widened and extruded by the T-die.
As another lamination method, a multi-manifold die method is mentioned, which is a method of widening the resin of each layer to a predetermined width in a T-die, and then converging and extruding the layers, and can be suitably used for producing the laminate film of the present invention.
The molten resin extruded in the above-described manner is extruded in a film form from the T-die, and then the difference between the speed of the resin passing through the exit portion of the T-die and the drawing speed by the drawing roll is adjusted to a predetermined thickness. Then, the resin is cooled by contact with the cooling roll having the adjusted temperature, and adjusted to a predetermined thickness.
In the above-described step, the surface of the pulling roll is embossed, and the resulting roll is pulled while being pressed against the surface of the surface layer in a softened state, thereby obtaining an embossed surface.
In the case of the vinylidene fluoride resin film of the present invention, since the film thickness is thin, it is preferable to use a pulling roll obtained by pressure-bonding a metal roll having mirror surface properties and a rubber roll having an embossed surface. Examples of a material that can be suitably used for the metal roller include a hard chrome-plated roller and the like, and examples of a material that can be suitably used for the rubber roller include a roller obtained by dispersing sand in a rubber made of silicone to form an embossed surface.
The grain size number of the roller for forming an embossed surface is not particularly limited, and a roller containing sand having a grain size of 320 to 800 may be suitably used.
The cooling temperature of the pulling roll is not particularly limited as long as it is in a range in which the emboss transferability to the surface of the surface layer is sufficiently obtained and the deformation or the like does not occur after the film is produced. For example, the temperature of the cooling water circulating in the rolls is preferably below 60 ℃, more preferably below 50 ℃. When the cooling temperature is 60 ℃ or higher, the film appearance may deteriorate.
The film cooled as described above is slit at the film edge to have an arbitrary film width, and then wound with an appropriate tension that does not cause the winding-up and the winding-off of the film, thereby obtaining the laminated film of the present invention.
[3. automobile or automobile parts ]
The vinylidene fluoride resin film or the laminate film of the present invention can be suitably used as a surface protective film for interior and exterior automotive decoration, for example.
Specific adherends of the surface protective film for interior and exterior decoration of an automobile include various interior decorative members such as instrument panels, dash panels, and doors, and various exterior decorative members such as a vehicle body, a front bumper, and a rear bumper.
A surface protective film may be used by being laminated with a decorative film subjected to design such as printing or coloring, and as a method for laminating a surface protective film with a decorative film, a method of heat lamination by a roll-to-roll method, a method of lamination with an adhesive, and the like are exemplified.
As a Method for laminating a film obtained by laminating a surface protective film on a decorative film and an interior base member, a Three-dimensional surface decoration processing Method can be suitably used, and as a typical Method, there is a TOM (Three dimensional Overlay Method) molding Method. The method comprises the following steps: various adhesives are applied to the side of the film, which is obtained by laminating a surface protective film on a decorative film, which is to be bonded to a base material member for interior decoration, and then the film is softened by heat and laminated by the difference in air pressure between the base material member side and the non-base material member side. Examples of the adhesive include, but are not particularly limited to, acrylic pressure-sensitive adhesives, hot-melt adhesives, and the like.
In the laminating method, the three-dimensional surface finishing method, and the like, even when heat and pressure are applied to the surface protective film, the matte feeling and matte feeling can be maintained by the unevenness caused by the crosslinked acrylate resin particles located in the vicinity of the surface layer.
For example, even in the case of an embossed surface protection film, the embossed surface itself is slightly flattened by the lamination to an adherend and the three-dimensional surface decoration method (fig. 2), and the glossiness can be maintained at a low level by the unevenness of the crosslinked
The performance of the surface protective film is directly and preferably evaluated by confirming the appearance as a laminate with another substrate, but the evaluation method of the film may be used instead of the physical properties such as internal haze, external haze and gloss, and the evaluation value is preferably within the above numerical range.
For example, as shown in fig. 3, when the
On the other hand, when light is irradiated onto the crosslinked acrylate resin particles, it is considered that diffusion occurs therein, and a matte feeling is generated.
In the lamination and three-dimensional surface decoration processing method, it is preferable that the adhesion to the adherend is sufficient but not excessively strong, and is performed by light pressure and heat.
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