JPH073047A - Fluororesin-based film - Google Patents

Abstract

PURPOSE:To obtain a fluororesin-based film capable of practically using for a long period while protecting printing ink which exists on the rear of a fluororesin-based film, an intermediate layer such as adhesive, a plastic, wood, steel material, etc., used as a substrate from deterioration due to ultraviolet rays. CONSTITUTION:This fluororesin-based film includes an inorganic compound having a function capable of substantially preventing transmission of rays in the area of at least ultraviolet rays and substantially not preventing transmission of rays in the area of visible light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororesin film, and more particularly to a fluororesin film which has a function of partially blocking light in a specific wavelength range and can be used outdoors for a long period of time.

[0002]

2. Description of the Related Art Conventionally, various resin films for preventing transmission of light rays in the ultraviolet range have been proposed. For example, there are films made of vinyl chloride resin (PVC), polyethylene resin (PE), polypropylene resin (PP), polyester resin (PET), and polycarbonate resin. It is obtained by blending or coating an ultraviolet absorber composed of a system ultraviolet absorber.

However, the organic UV absorbers used for these resins are inferior in heat resistance and have no durability, so that they cannot be used in the fluororesin system. Specifically, since the heat molding temperature of most fluororesins is approximately 300 ° C. or higher, most of the above-mentioned UV absorbers are thermally decomposed, and in the fluororesin film, they are substantially blended. It wasn't there.

Further, even if it remains very slightly, the ultraviolet absorber has a short durability of several years, and its compatibility with the fluororesin is extremely low, so that it is not suitable for the fluororesin to be used for a long time. , Was not practically usable.

[0005] Further, it is well known that one of the resins having excellent durability is a fluororesin. However, these fluororesin films are printed on the back surface of the film rather than being used as a film alone. In many cases, there is a demand for using it as a durable material by laminating it on the surface of plastics, wood or steel as a base material after bonding or processing with an adhesive. However, for the reasons described above, it is practically impossible to block ultraviolet rays, so that the printing ink and the adhesive discolor in a short period of time, or the adhesive function deteriorates, which is not practical. Was not in widespread use.

[0006]

DISCLOSURE OF THE INVENTION The object of the present invention is to solve the above-mentioned problems that conventional fluororesin films have, and is a novel fluorine which has not been known until now. It is to provide a resin film.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and substantially blocks the transmission of light rays in at least the ultraviolet region and substantially transmits the light rays in the visible light region. It is an object of the present invention to provide a fluororesin-based film which is characterized by including an inorganic compound having a function of not blocking.

According to the present invention, however, the printing ink, the intermediate layer material such as an adhesive, and the base plastics, wood, steel and the like which are present on the back surface of the fluororesin film are protected from ultraviolet deterioration. Thus, a fluororesin film that can be used for a long period of time can be obtained. Hereinafter, the constituent factors of the present invention will be described in more detail.

The "fluororesin" used in the fluororesin film of the present invention is a general term for synthetic resins containing fluorine. In the present invention, the fluorine content is generally 35% by weight or more, and further 40% by weight. Above all, especially 55% by weight or more is preferably used. As such a fluororesin,
For example, ethylene-tetrafluoroethylene-based copolymer,
Ethylene-chlorotrifluoroethylene-based copolymer, hexafluoropropylene-tetrafluoroethylene-based copolymer, perfluoroalkylvinylether-tetrafluoroethylene-based copolymer, polyvinylidene fluoride,
Examples thereof include polyvinyl fluoride, and any of these can be used in the present invention, but among them, an ethylene-tetrafluoroethylene-based copolymer is preferable.

The ethylene-tetrafluoroethylene copolymer is mainly composed of ethylene and tetrafluoroethylene (the molar ratio of ethylene / tetrafluoroethylene is generally 40/60 to 60/40), and if necessary, It is a copolymer of a small amount (usually 10 mol% or less) of the third comonomer component, and in the present invention, particularly, the ethylene / tetrafluoroethylene content molar ratio is 40/60 to 60/40,
Preferably within the range of 45/55 to 55/45 and of the formula CH _{2
= CH-CnF 2 n + 1} ( where, n is an integer of 2 to 10) Pas represented by - fluoroalkyl vinyl monomer - units _{(e.g., CH 2 = CH-C 4} H 9 or CH ₂ = CH the content of derived units) from -C ₆ H ₁₃ 0.1 to 10 mol%, preferably ethylene in the range of 0.3 to 5 mole% - is suitably tetrafluoroethylene copolymer is used. This ethylene-tetrafluoroethylene-based copolymer is known per se, and can be produced, for example, by the method described in JP-B-59-50163, and as a commercial product, Asahi Glass Co., Ltd. It is also possible to use a commercially available product under the trade name "COP".

The film formation from the above-mentioned fluororesin is carried out according to a method known per se, for example, an extrusion molding method,
It can be performed by an inflation molding method or the like.

In the present invention, the "ultraviolet region" is not particularly limited and may be any wavelength as long as it is in the ultraviolet region, but at least 300 to 330 nm in the wavelength region.
Is a light beam containing 300 to 360 nm, and further a light beam having a wavelength of 300 to 380 nm. Further, the "visible light region" is not particularly limited, as long as the wavelength of the visible light region, any region,
A light beam having a wavelength range of at least 450 to 600 nm,
Generally, it also contains light of 400 to 800 nm.

In the present specification, the term "substantially block the transmission of light rays in the ultraviolet region" means not only the case of completely blocking the transmission of light rays in the ultraviolet region, but also the transmission of light rays in the ultraviolet region. At least 50% or more, preferably 70% or more, more preferably 80% or more, particularly preferably 90% or more, is used in the sense of including the case.

The term "does not substantially block the transmission of light rays in the visible light region" means not only the case of completely transmitting the light rays in the visible light region but also the transmission of the light ray in the visible light region at least. 70% or more, preferably 80% or more, more preferably 85% or more, and particularly preferably 88% or more are used in the meaning to include the case.

Further, examples of the inorganic compound used in the present invention include titanium oxide (TiO ₂ ), zinc oxide (Zn
O), mica, alumina (Al ₂ O ₃ ), tin oxide (SnO ₂ ), colloidal silica (SiO ₂ ), iron oxide (Fe ₂ O ₃ ), antimony oxide (Sb ₂ O ₃ ), indium oxide (In ₂ O ₃ ), ITO and the like, and among them, TiO ₂ and ZnO are preferable. The particle size of these inorganic compounds is not particularly limited, and may be any particle size, for example, 1 μm or less, preferably 0.5 μm or less, particularly preferably 0.1 μm or less, more preferably 0.05 μm or less, particularly preferably It is 0.02 μm (20 nm) or less.

The blending amount of these inorganic compounds in the film varies depending on the resin used and the film thickness, but is generally 0.001 to 10% by weight, preferably 0.01 to 5% by weight. , And more preferably 0.1 to 1% by weight.

In the present invention, the effect of the present invention can also be obtained by applying the above-mentioned inorganic compound on the surface of the fluororesin film.

As a coating method, it is also possible to mix a binder and an inorganic compound having an action of holding the above-mentioned inorganic compound, disperse this in a solvent, and then coat on a fluororesin film.

In order to industrially carry out the coating treatment, it is important to previously subject the fluororesin film to the surface activation treatment. The surface activation treatment enables firm adhesion to the coating layer, and also prevents cissing of the solution when coating.

Examples of such surface activation treatment include corona discharge treatment, sputter etching treatment, sodium treatment, sandblast treatment and the like. Corona discharge treatment is performed by discharging between a needle-shaped or knife-edge electrode and a counter electrode, and inserting a sample in between to perform treatment, such as aldehyde, acid, alcohol peroxide, ketone, ether, etc. on the film surface. This is a treatment for generating a functional group containing oxygen.

The sodium treatment is a treatment of immersing the film in a liquid ammonia solution of an alkali metal such as sodium metal, which is a treatment of eliminating CF ₂ bonds from the surface and forming CH and CO bonds.

The sputter etching process uses a low pressure group.
A sample is put between the electrodes that are discharging, and a large number of fine projections are formed on the film by the impact of positive ions generated by the glow discharge.

The sandblast treatment is to spray fine sand on the film surface to form a large number of fine irregularities on the surface. Among these surface activation treatments, in terms of adhesion with the coating layer, workability, safety, cost, etc.,
It is preferable to perform corona discharge treatment.

The coating layer containing an inorganic compound may be formed by coating the inorganic compound itself to form the coating layer, or may be formed by coating a mixture of the inorganic compound and a binder solution to form the coating layer. In addition to the inorganic compound, a surfactant, a hydrophilic polymer, and a mixture of two or more of these may be added to the coating layer containing the inorganic compound in the present invention.

Examples of such a surfactant include, for example,
Sorbitan fatty acid ester, sorbitol fatty acid ester, diglycerin fatty acid ester, glycerin fatty acid ester, sorbitan fatty acid dibasic acid ester, sorbitol fatty acid dibasic acid ester, diglycerin fatty acid dibasic acid ester, glycerin fatty acid dibasic acid ester and Examples thereof include compounds in which alkylene oxide such as ethylene oxide and propylene oxide is added.

Examples of the hydrophilic polymer include, for example, polyvinyl alcohol, polyvinylpyrrolidone and the like, as well as -SO ₄ , -SO ₃ H, -COOH, -CN,-(0 CH ₂ CH ₂ ), and the like. Generally, polymers having hydrophilic functional groups are included.

Examples of the binder include (meth) acrylic acid ester resin and vinyl acetate resin. Solvents, additives and the like may be added to the coating composition containing the above-mentioned inorganic compound for the purpose of improving workability and surface smoothness. As the solvent, for example, water, various alcohols, ketones, esters, ethers and the like can be appropriately used.

The above coating composition may be applied to a fluororesin film by brush coating, dip coating,
It is possible to use commonly known methods such as gravure coating and spray coating.

The amount of the inorganic compound used here is
Depending on the film thickness applied, the binder used, and the amount of other additives, it is 0.5 to 95% by weight, preferably 1 to 50% by weight, more preferably 3 to 30% by weight in the dry coating film. is there.

The fluororesin-based film thus obtained is a material that is particularly required to have outdoor durability, such as exterior building materials, road signs, signboards, chemical plants such as tanks and pipes, and civil engineering such as bridges and dams. It is used in a very wide range as a film for laminating the surface of a substrate such as a building, and is a great contribution to the industry.

Hereinafter, the present invention will be described in more detail by way of examples, but it goes without saying that the present invention is not limited to the examples.

[0032]

【Example】

Comparative Example 1 Trichloromonofluoromethane 3.46 kg, trichlorotrifluoroethane 6.52 was added to an autoclave having an internal volume of 10 liters.
kg, and t-butyl peroxyisobutyrate 2.38 g were charged, and then futrafluoroethylene 1226 g and ethylene 8
2g, and Pa - perfluorobutyl ethylene _{(CH 2 = CH-C 4} F 9)
Charge 26g. While sufficiently stirring this mixture, the reaction temperature is kept at 65 ° C. to carry out the copolymerization reaction. During the progress of the copolymerization reaction, tetrafluoroethylene / ethylene /
A mixed gas having a molar ratio of perfluorobutylethylene of 53 / 46.3 / 0.7 is introduced to maintain the polymerization pressure at 15.0 kg / cm ₂ . After 5 hours, 460 g of a white copolymer was obtained (hereinafter referred to as resin No. 1). The copolymer is C ₂ F ₄ / C ₂ H ₄ / CH ₂ = C
The content molar ratio of HC ₄ F ₉ was 53 / 46.3 / 0.7, and the flow starting temperature was 267 ° C and the thermal decomposition starting temperature was 360 ° C.

Ethylene-tetrafluoroethylene copolymer obtained above (hereinafter sometimes abbreviated as "ETFE")
Was extruded at a resin temperature of 320 ° C. to produce a film having a thickness of 50 μm. The film obtained was used as coating material No. 1 and subjected to various tests, and the results are summarized in Table 1 below.

Examples 1 to 4 Film No. 1 prepared in Comparative Example 1 has the 0.02 content shown in Table-1.
Film No. 1 except that μm TiO ₂ and ZnO were added
Film Nos. 2 to 5 were prepared in the same manner as in.

Example 5 One surface of film No. 1 prepared in Comparative Example 1 was charged with discharge current 1
Corona discharge treatment was performed under the conditions of 0 A, discharge voltage 120 V, and line speed 13 m / min. Treated surface with silica sol (silica solid content 8%), polyvinyl alcohol 5wt% and TiO ₂ 5wt
% Diluted with ethanol to 100% added,
It was coated so that the amount of silica would be 15 g / m ₂ to obtain a film (film No. 6).

[0036]

[Table 1]

Reference Example 1 One surface of the films No. 1 to 5 obtained in the example and the TiO ₂ non-coated surface of the film No. 6 were subjected to corona discharge treatment under the same conditions as in the example 5, and then gravure printing was performed. Machine, wood grain printing is performed, and then acrylic adhesive (NISSET
Nisetsu PE-154, manufactured by Co., Ltd.) was diluted with toluene to a nonvolatile concentration of 30%, and then coated at 60 g / m ₂ and dried.

[0038] These films are laminated on a white PVC plate, which is then applied to a sunshine weather meter (WOM).
Table-2 shows the results of condition observation after exposure and irradiation time of 1,000, 2,000, and 3,000 hours.

[0039]

[Table 2]

Next, the observation items and evaluation criteria are shown. (1) Degree of discoloration of printing ink, ⊚: No discoloration is observed. ◯: A slight discoloration is seen, but practically no problem. Δ: Discoloration is observed, but it can be used except for some applications. X: Discoloration is remarkable and cannot be practically used.

(2) Degree of decrease in adhesive strength A: No decrease in strength is observed. ◯: A slight decrease is seen, but practically no problem. Δ: Decreased, but usable except some applications. X: The deterioration is remarkable, and it cannot be practically used.

(3) Degree of yellowing of white PVC plate ⊚: No yellowing is observed. ○: A slight yellowing is observed, but practically no problem. Δ: Yellowing is observed, but it can be used except for some applications. X: Yellowing is remarkable and cannot be practically used.

Claims (10)

[Claims] 1. A fluororesin-based film comprising an inorganic compound having a function of substantially blocking transmission of light rays in at least an ultraviolet region and not substantially blocking transmission of light rays in a visible light region. . 2. The fluororesin film according to claim 1, wherein the ultraviolet region is 300 to 330 nm. 3. The fluororesin film according to claim 1, wherein the visible light region is 400 to 800 nm. 4. The fluororesin film according to claim 1, which has a light transmittance of 50% or less in the ultraviolet region. 5. The fluororesin film according to claim 1, wherein the inorganic compound is TiO ₂ and / or ZnO. 6. The fluororesin film according to claim 1, wherein the content of the inorganic compound is in the range of 0.001 to 10% by weight. 7. The fluorine content of the fluororesin is 40% by weight.
The above is the fluororesin film according to any one of claims 1 to 6. 8. The fluororesin film is ethylene-based.
Tetrafluoroethylene-based copolymer, ethylene-chlorotrifluoroethylene-based copolymer, hexafluoropropylene-tetrafluoroethylene-based copolymer, per-fluoroalkyl vinyl ether-tetrafluoroethylene-based copolymer, polyfluorination The fluororesin film according to any one of claims 1 to 7, which is a film formed from a resin selected from vinylidene and polyvinyl fluoride. 9. The fluororesin film is ethylene-based.
The fluororesin film according to any one of claims 1 to 8, which is a film of a tetrafluoroethylene copolymer. 10. The ethylene-tetrafluoroethylene copolymer has an ethylene / tetrafluoroethylene content molar ratio in the range of 40/60 to 60/40, and has the formula CH _{2
= CH-CnF 2 n + 1} ( where, n represents an integer of 2 to 10) Pas represented by - fluoroalkyl vinyl monomers - ethylene content of units is within the range of 0.1 to 10 mol% - tetra The fluororesin film according to claim 8, which is a fluoroethylene copolymer.