JPH05310973A - Modified fluorine-containing resin film - Google Patents

Abstract

PURPOSE:To provide the film for horticultural purposes having an inorganic particle layer to sustain light transmission properties, thus showing excellent anti-fogging properties by coating a fluorine-containing resin film with a coating agent containing inorganic particles such as SiO2 and a binder bearing polar groups on its surface. CONSTITUTION:Film of a fluorine-containing resin such as an ethylene- tetrafluoroethylene copolymer is coated at least on one surface with a coating agent containing 100 pts.wt. of inorganic particles such as SiO2 particles of 5 to 30mmu average size and 0.1 to 40 pts.wt. of a binder bearing polar groups such as beta-(3,4-epoxycyclohexylethyltrimethoxysilane), as essential components, with a gravure coater so that the inorganic particles becomes 0.1 to 1.3g/m<2> to give the improved fluorine-containing resin film which is useful for green houses in horticulture or for surface cover of reflexively reflective sheets because it has inorganic particle layer on its surface and shows excellent anti- fogging properties for a long period of time without impairing light transmission.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorine-containing resin film, and more particularly to a modified fluorine-containing resin film comprising a surface-modified fluorine-containing resin film.

[0002]

2. Description of the Related Art Conventionally, various fluorine-containing resin films modified with a fluorine-containing resin film have been proposed. As is clear from these proposals, the fluorine-containing resin film, unlike a thermoplastic resin such as a vinyl chloride resin, has a film forming processing temperature of 300 ° C. or higher, which is an extremely high temperature. Since the film surface modifiers such as a hydrophilic lubricant and an antifogging agent are thermally decomposed, it was impossible to add them directly into the resin.

When the fluorine-containing resin film is used for agriculture, for example, for coating a greenhouse for facility gardening, water vapor in the house is condensed on the surface of the house, which becomes water droplets and drops on the agricultural products. However, there were problems such as the occurrence of diseases, the reduction of yield and the deterioration of quality. Further, when this is used for the retroreflective sheet surface coating film, there is a problem that water droplets such as rain and fog adhere to the film and the retroreflective function is extremely deteriorated.

In order to solve these problems, particles mainly composed of Al ₂ O ₃ were applied to the surface of the film. However, in the case of the fluorine-containing resin, not only these particles are difficult to adhere to each other, but also these surface treatments are carried out. There is a problem that the antifog effect cannot be obtained when the coating amount is small, and the light transmission amount of the film is reduced when the coating amount is large. As described above, since there was no treating agent having excellent antifogging property and excellent transparency, development of a fluorine-containing resin film excellent in antifogging property was not realized at all.

[0005]

DISCLOSURE OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the prior art, and a modified fluorine-containing resin system which has never been known. To propose a new film.

[0006]

The present invention has been made to solve the above-mentioned problems, and at least one surface of a fluororesin-based film contains 100 parts by weight of inorganic particles mainly composed of SiO ₂ and a polar group-containing film. Binder-0.1 to 40 parts by weight of the coating agent as an essential component, the inorganic particles 0.1 ~ 1.3g / m2
The present invention provides a modified fluorine-containing resin-based film having an inorganic particle layer (A) coated so that

Thus, according to the present invention, a modified fluorine-containing resin film having excellent antifogging property, which does not impair the light transmittance of the film and lasts for a long time, is obtained. Be done. The constituent factors of the present invention will be described in detail below.

In the present invention, the "fluorine-containing resin" means
It is not particularly limited as long as it is a thermoplastic resin containing fluorine in the molecular structural formula of the resin, and specifically, for example, tetrafluoroethylene-based resin having four fluorine atoms in the resin structure, Furthermore, it is a trifluoroethylene-based resin, a difluoroethylene-based resin, a monofluorinated ethylene-based resin and a composite of these resins, and among them, a tetrafluoroethylene-based resin and a difluorinated ethylene-based resin are preferable, and A fluorinated ethylene resin is preferred.

Here, the tetrafluoroethylene-based resin is specifically, for example, tetrafluoroethylene-based resin (PTFE), tetrafluoroethylene / perfluoroalkoxyethylene copolymer.
(PFA), tetrafluoroethylene / hexafluoropropylene / perfluoroalkoxyethylene copolymer (EPE) tetrafluoroethylene / hexafluoropropylene copolymer (FEP) and tetrafluoroethylene / ethylene copolymer ( ETFE) etc.
PFA, ETFE, FEP and EPE are preferred, and ETFE is particularly preferred.

Explaining ETFE in detail, ethylene and tetrafluoroethylene are the main components (the molar ratio of ethylene / tetrafluoroethylene is generally 40/60 to 60/40),
If necessary, a small amount (usually 10 mol% or less) of a third comonomer component is copolymerized therewith, and in the present invention, particularly, the ethylene / tetrafluoroethylene content molar ratio is 40/60 to Perfluoroalkyl in the range of 60/40, preferably 45/55 to 55/45, and of the formula CH ₂ ═CH—CnF _{2n + 1,} where n is an integer from 2 to 10. Vinyl monomer units (eg CH ₂ = CH-C ₄ H ₉ or CH ₂ = CH-C ₆ -CH
ETFE having a content of (units derived from ₁₃ ) in the range of 0.3 to 10 mol%, preferably 0.3 to 5% mol is preferably used.

This ETFE is known per se, and can be produced, for example, by the method described in Japanese Patent Publication No. 59-50163, and as a commercial product, "Aflon C" from Asahi Glass Co., Ltd.
It is also possible to use a commercially available product under the trade name "OP".

The above trifluoroethylene resin is
Specifically, for example, trifluorochloroethylene resin (CTFE) and trifluorochloroethylene / ethylene copolymer (ECTFE)
Etc., among which CTEFE is preferable. Specifically, the ethylene difluoride-based resin and the ethylene monofluoride-based resin are, for example, vinylidene fluoride resin (PVDF) and vinyl fluoride resin (PVF).

Further, in the present invention, a mixture with another thermoplastic resin mainly containing the above-mentioned fluorine-containing resin may be used.

Further, the "inorganic substance" of the "inorganic particles" in the present invention is an inorganic substance mainly composed of SiO ₂ , and its composition is not only 100 wt% of SiO _2, but generally 50 wt% or more. , Preferably 70 wt% or more, more preferably 80 wt% or more. The inorganic substance other than SiO ₂ is not particularly limited and may be any inorganic substance such as Al ₂ O ₃ and Ti.
There are O ₂ , MgCO _3, CaCO _{3 and the} like, and among them, Al ₂ O ₃ is preferably used.

The shape of the inorganic particles is not particularly limited, but it is preferably spherical, and particles within the range of ordinary colloidal particles can be used, but the transparency of the obtained coating film is good. From the viewpoint of, the average particle size is 1 to 100
mμ, preferably 3 to 50 mμ, more preferably 5 to 30 mμ
Is.

Further, the layer A composed of the above-mentioned inorganic particles further contains a cationic, anionic, amphoteric surfactant and / or nonionic surfactant in addition to the above-mentioned inorganic substance, whereby the antifogging property is further improved. Sex is given. The amount of surfactant used in the A layer is generally 0.1-40 wt%, preferably 0.2-15 wt%, more preferably 0.3-10 wt%. When the amount of surfactant is more than 40 wt%, the resulting coating film has poor weather resistance, durability, bleed resistance, and adhesion, and tends to have a short duration of antifogging property. Is not preferable because the antifogging property of the obtained coating film is lowered.

Examples of the cationic surfactants used herein include primary amine salts, secondary amine salts, tertiary amine salts, quaternary ammonium salts, hydroxyammonium salts,
Examples thereof include aliphatic amine salts such as ether ammonium salts and quaternary ammonium salts thereof, aromatic quaternary ammonium salts such as benzalkonium salts and bentonium salts, pyridinium salts, imidazolinium salts and fluorine-based salts.

Of these, pyridinium salt-based compounds, aliphatic amine salt-based compounds, quaternary ammonium salt-based compounds, and fluorine-based compounds are preferred, and among these, fluorine-based compounds such as perfluoroalkyl trimethyl ammonium salts and perfluoroalkyl quaternary ammonium salts. , Perfluoroalkylamine oxide, etc. are particularly preferable from the viewpoint of antifogging effect and sustainability.

Further, the anionic surfactant is not particularly limited, and for example, as a carboxylate type,
Fatty acid and rosin acid soap, N-acyl carboxylate, ether carboxylate, sulfonates such as alkyl sulfonate, sulfosuccinate, ester sulfonate, alkylallyl and alkylnaphthalene sulfonate, N-acyl Sulfonate, sulfate ester type, sulfated oil, ester sulfate, alkyl sulfate, ether sulfate, alkyl allyl ether sulfate,
Examples of the amide sulfates and phosphoric acid ester salts include alkyl phosphates, ether phosphates, alkylallyl ether phosphates, amide phosphates, formalin condensed sulfonates, and fluorine-based ones.

Of these, carboxylic acid salts, phosphoric acid ester salts, and fluorine-based ones are preferable, and among them, fluorine-based ones such as perfluoroalkylcarboxylic acid salts and perfluoroalkylphosphoric acid esters are included. And particularly preferable in terms of durability.

Examples of amphoteric surfactants include betaine-based carboxybetaine, sulfobetaine, aminocarboxylic acid salt-based, imidazoline derivative-based and fluorine-based surfactants. Among these, fluorine-based ones such as perfluoroalkyl betaine can be mentioned, and particularly preferable from the viewpoints of antifogging effect and sustainability.

As the nonionic surfactant, for example, alkyl and alkylallyl polyoxyethylene ether, alkylallyl formaldehyde condensed polyoxyethylene ether, glycerin ether and its polyoxyethylene ether, and polyoxypropylene are used as lipophilic groups. Block polymer, alkylthiopolyoxyethylene ether, propylene glycol ester polyoxyethylene ether, glycerin ester polyoxyethylene ether, sorbitan ester polyoxyethylene ether, sorbitol polyoxyethylene ether ester, glycerin ether ester , Alkyl polyoxyethylene ether ester copolymer polyoxyethylene ether ester, polyoxyethylene fat Acid ester, glycerol ester,
Sorbitan ester, dihydric alcohol ester, sucrose ester, aliphatic alkanolamide, polyoxyethylene fatty acid amide, alkanolamine ester, polyoxyester alkylamine, amine oxide, perfluoroalkylethylene oxide adduct, perfluoroalkyl oligomer and Examples thereof include fluoroalkyl ethylene oxide adducts.

Among them, alkyl and alkylallyl polyoxyethylene ethers, polyoxyethylene fatty acid esters, glycerin esters, sorbitan esters, perfluoroalkylethylene oxide adducts, perfluoroalkyl oligomers and fluoroalkylethylene oxide adducts are preferred, and particularly peroxyethylene oligomer adducts. Fluoroalkyl ethylene oxide adducts, perfluoroalkyl oligomers and fluoroalkyl ethylene oxide adducts are particularly preferable from the viewpoints of antifogging effect and sustainability.

In order to obtain the layer A on the surface of the fluorine-containing resin film of the present invention, a dispersion liquid in which the above-mentioned inorganic particles and a surfactant are once uniformly dispersed in a dispersion medium is prepared, and this is placed on the film surface. It is achieved by coating and drying.

The dispersion medium used here is not particularly limited and is appropriately selected in consideration of the inorganic particles and the surfactant to be used. Generally, for example, water, methyl alcohol, ethyl alcohol, Isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, ethyl cellosolve, ethylene glycol, acetone, glycerin, amyl acetate acetate, monoethyl ether, n-methylpyrrolidone, methyl ethyl ketone,
There are dimethylformamide, triethanolamine and the like, and among them, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, acetone and ethylene glycol are preferably used.

From the viewpoint of coating property, it is desirable that the water content is low, and the water content in the dispersion is 4 in terms of H ₂ O / SiO ₂ weight ratio, preferably 1
Is allowed up to. When the amount of water in the dispersion liquid is more than 4 in terms of H ₂ O / SiO ₂ weight ratio, it is not preferable because a uniform coating film may not be formed during coating to form a coating film.

The concentration of the inorganic particles in these dispersion media is not particularly limited, but is generally 50 wt% or less, preferably 5 to 30 wt%.

This dispersion medium may be further diluted to a suitable concentration before use. In particular, when an acidic organosilica sol having a pH of 5 or less is mixed with a surfactant, it is preferable because it is stable for a long period of time. In addition, such an organosilica sol is produced from a silica sol having water as a dispersion medium, for example, by the method described in Japanese Patent Publication No. 2-1087 filed previously.

Further, in the present invention, the "binder" is a general term for substances having a property of bonding the fluorine-containing resin film and the inorganic particles to each other, and is not particularly restricted and any binder can be used. ..

As the binder, for example, synthetic or natural rubber, recycled rubber, polyvinyl acetate homopolymer, vinyl acetate-acrylic acid ester copolymer, vinyl acetate-
Ethylene copolymer, polyvinyl alcohol (Poverer
), Polyvinyl acetal, poly (meth) acryle
, Cyanoacrylate, tetraethylene glycol dimethacrylate, phenol resin, resorcinol resin, xylene resin, furan resin, urea resin, melamine resin, epoxy resin, polyfunctional epoxy resin, polyurethane, starch, dextrin , Rosin, rosin derivatives, silane coupling agents and the like, acrylic ester copolymers, epoxy resins, rosins, rosin derivatives and silane coupling agents are preferable, and silane coupling agents are particularly preferable.

The silane coupling agent is an organosilicon monomer having two or more different reactive groups in the molecule. One of the reactive groups is a reactive group that chemically bonds to the inorganic particles (for example, a methoxy group, an ethoxy group, and a cellosolve group), and the other one is a reactive group that chemically bonds to the synthetic resin (for example, vinyl. Group, epoxy group, methacryl group, amino group, mercapto group, etc.).

It is important that the coating agent in the present invention contains inorganic particles mainly composed of SiO ₂ and a polar group-containing binder as essential components. Here, the mixing ratio of the inorganic particles and the polar group-containing binder is 100 parts by weight of the inorganic particles, the polar group-containing binder is 0.1 to 40 parts by weight, preferably 0.2 to 20 parts by weight, more preferably 0.3 to 10 parts by weight. Parts by weight,
It is particularly preferably 0.5 to 5 parts by weight.

Further, the "polar group-containing binder" of the present invention
The "polar group" in is not particularly limited,
Although it may be any polar group, generally, for example, an epoxy group, a hydroxyl group, a carboxyl group, a carbonyl group, an amino group, a chloro group, a mercapto group, a vinyl group, a phenyl group and the like, preferably an epoxy group. , A hydroxyl group, a carboxyl group, an amino group and the like, and an epoxy group is particularly preferable.

As described above, a conventionally used method can be used for applying the prepared coating agent to the surface of the fluororesin film, for example, a gravure roll method, a roller touch method, a bar coater. The coating can be performed by a usual coating method such as a coating method, a spray method, a dipping method, and a brush coating method. Among these, the gravure roll method is preferable.

The amount of the inorganic particles applied on the surface of the fluororesin film is 0.1 to 1.3 g / m ² , preferably 0.1 to 1.3 g / m ² .
1.0 g / m ^2, more preferably it is important to the 0.1 to 0.5 g / m ^2. If the coating amount is less than 0.1 g / m ² , an appropriate antifogging effect cannot be obtained, and if it exceeds 1.3 g / m ² , the light transmittance is lowered, which is not preferable.

When the coating amount is within the range of the present invention, not only a remarkable antifogging effect can be obtained, but also in light transmittance,
It is surprising that the light transmittance of the original film before applying the inorganic particles is equal to or slightly improved, but it is surprising that it is extremely useful as a surface coating film for facility gardening houses or retroreflective sheets. It will be useful.

The modified fluororesin film thus obtained has an excellent antifogging property without impairing the light transmittance of the film, and is extremely large when applied to the industry. Is. The present invention will be described in more detail with reference to the following examples, but it goes without saying that the present invention should not be limited to the examples.

[0038]

【Example】

Example A (Preparation of Inorganic Particle Dispersion) (1) Silica sol with water as dispersion medium (SiO ₂ concentration 20 wt%,
After thoroughly mixing 1000 ml of average particle size 11 nm, Al ₂ O ₃ / SiO ₂ = 0.002 molar ratio) and 1000 ml of isopropyl alcohol (purity 99% or more), filtration was performed with an ultrafiltration membrane, and the filtrate was 1000 ml.
When the temperature reached, 1000 ml of fresh isopropyl alcohol was added to the mother liquor. After that, perform filtration in the same manner and filtrate 10
00 ml was collected. Repeat this operation a total of 6 times,
Colloidal silica having a silica concentration of 30 wt% and isopropyl alcohol as a dispersion medium was obtained. The water concentration in this sol is
At 2.7 wt%, the pH of the sol was 2.1 and the viscosity was 5.6 cp.

32 g of this colloidal silica having isopropyl alcohol as a dispersion medium, and a perfluoroalkyl phosphate ester surfactant (Asahi Glass Co., Ltd .; Surflon S-11
2, solid concentration 15%) 1 g of isopropyl alcohol 150 g
The inorganic particle dispersion liquid was prepared by mixing with the solution diluted with (hereinafter, this is referred to as "dispersion liquid 1", which is used in Comparative Example).

Next, the polar group-containing binder shown in Table 1 was added to this dispersion liquid 1 to prepare a uniformly mixed dispersion liquid (hereinafter referred to as "dispersion liquid 2"). The binders and their Nos. Used here are as follows. No.1 β- (3,4 epoxycyclohexylethyltrimethoxysilane) (containing polar groups) No.2 Butyl acrylate-acrylic acid copolymer
(Containing polar group) No.3 Chlortrifluoroethylene-tetrafluoroethylene-hydroxyvinyl ether copolymer
(Contains polar group) No.4 γ-methacryloxypropyltrimethoxysilane (no polar group)

Example B (Preparation of Ethylene-Tetrafluoroethylene Copolymer Film) (1) Polymerization of Ethylene-Tetrafluoroethylene Copolymer In an autoclave with an internal volume of 10 liters, 3.46 kg of trichloromonofluoromethene and trichlorotriene were added. Fluoroethane
6.52 kg, and t-butyl peroxyisobutyrate 2.38
g, then tetrafluoroethylene 1226 g, ethylene 82 g, and perfluorobutyl ethylene (CH ₂ = CH-C ₄
F ₉ ) Charge 26g. In this case, the reaction temperature is kept at 65 ° C. while sufficiently stirring the product to carry out the copolymerization reaction.

During the progress of the copolymerization reaction, a mixed gas of tetrafluoroethylene / ethylene / perfluorobutylethylene having a molar ratio of 53 / 46.3 / 0.7 was introduced into the system to adjust the polymerization pressure to 15.
Hold at 0 kg / cm ² . After 5 hours, 460 g of a white ethylene-tetrafluoroethylene copolymer (ETFE) was obtained. The copolymer has a molar ratio of C ₂ F ₄ / C ₂ H ₄ / CH ₂ = CH ₄ CF ₉ of 53/46.
3 / 0.7, flow start temperature 267 ℃, heat dispersion start temperature 360
It was ℃.

(2) Preparation of ETFE Film The ETFE obtained in (1) above was extruded at a resin temperature of 320 ° C. to obtain a film having a thickness of 50 μ. The physical properties are shown in Table 1.

Example C (Coating of Inorganic Particle Liquid) Examples 1 to 7 and Comparative Examples 1 to 7 One surface of the ETFE film obtained in Example B was discharged at a current of 10 A, a discharge voltage of 120 V and a line speed of 13 m / m. Corona discharge treatment was performed under the condition of min, and then the treated surface was subjected to Example A.
The dispersions 1 and 2 prepared in Step 1 were coated with a gravure coater to obtain a film coated with inorganic particles as shown in Table 1.

[0045]

[Table 1]

Examples 8 to 9 (Preparation of PVF and PVDF film) As PVF film, Tedlar 200SG40TR manufactured by DuPont.
(Film thickness 50μ) and FVDF film, manufactured by Mitsubishi Petrochemical Co.,
Kainer FH ₂ (film thickness 50 μm) was prepared, and 0.3 g / m ^{2 of} inorganic particles was applied to these films in the same manner as in Example 1.
The physical property values of these films are shown in Table 1. The methods for measuring the physical properties of the film shown in Table 1 and the methods for evaluating them are as follows.

(1) Composition of coating agent The content of the binder is 100 parts by weight per 100 parts by weight of the inorganic particles.

(2) Light transmittance The total light transmittance was measured according to JIS K7105.

(3) Sustainability of anti-fogging property The anti-fogging property is set to the inside, and this is coated on a beaker containing hot water of 40 ° C. and kept for 18 months as it is. Observe. "Evaluation Criteria" 5-Anti-fogging Deteriorated area is less than 10%, and the anti-fogging property is completely maintained, and the anti-fogging property is extremely excellent. 4-Anti-fog deterioration area is in the range of 10% to less than 30%,
It has excellent anti-fog properties. 3-The anti-fogging deterioration area is in the range of 30% to less than 50%, but it can be practically used. 2-Anti-fog deterioration area is in the range of 50% to less than 70%,
Practical use is limited. 1-Anti-fogging Deterioration area is 70% or less, and there is no anti-fogging property, and it is not practical.

(4) Adhesion Normal Adhesion ETFE adhesive tape (film thickness 60 μ,
A pressure-sensitive adhesive layer (20 μ) was attached, and a 180-degree peel test was performed in accordance with JIS Z0237. Water-resistant adhesion In the above, the sample to which the ETFE adhesive tape was adhered was previously
A peeling test was performed in the same manner as above except that it was immersed in water at 23 ° C. for 5 hours. "Evaluation criteria" 5-Peeling load is 500 g / inch or more, and excellent adhesion. 4-〃 Less than 200-500g / inch, excellent adhesion. 3-〃 Less than 100-200g / inch, but practically usable. 2-〃 Less than 10-100g / inch, practical use is limited. 1-〃 less than 10g / inch, practically unusable.

Claims (12)

[Claims] 1. At least one of fluorine-containing resin films
On the surface, a coating agent having 100 parts by weight of inorganic particles mainly composed of SiO ₂ and a polar group-containing binder-0.1 to 40 parts by weight as an essential component, so that the inorganic particles become 0.1 to 1.3 g / m ^2. A modified fluorine-containing resin-based film having an inorganic particle layer (A layer) applied to the film. 2. The modified fluorine-containing resin film according to claim 1, wherein the inorganic particles are coated in an amount of 0.1 to 0.5 g / m ² . 3. The modified fluorine-containing resin film according to claim 1, wherein the SiO ₂ particles have an average particle size of 5 to 30 mμ. 4. The SiO ₂ particles have a spherical shape.
And the modified fluorine-containing resin film according to any one of 3 and 4. 5. The modified fluorine-containing resin film according to claim 1, wherein the layer A is mainly composed of inorganic particles and a cationic and / or nonionic surfactant. 6. The modified fluororesin film according to claim 1, wherein the fluororesin is a tetrafluoroethylene-based resin. 7. The ethylene tetrafluoride resin is ethylene
The modified fluororesin film according to claim 6, which is a tetrafluoroethylene copolymer (ETFE). 8. The modified fluororesin film according to claim 1, wherein the modified fluororesin film has a visible light transmittance of 90 to 94%. 9. The improvement according to claim 1, wherein the A layer is formed by applying a stable organic solvent dispersion liquid containing colloidal silica and a surfactant having a fluoroalkyl group in the molecule. Fluorine-containing resin-based film that has been improved. 10. The modified fluorine-containing resin film according to claim 1, wherein the polar group is at least one selected from an epoxy group, a hydroxyl group and a carboxyl group. 11. The modified fluorine-containing resin film according to claim 1, wherein the binder is mainly composed of a silane coupling agent. 12. The modified fluororesin film according to any one of claims 1 to 11, wherein the fluororesin film is for a greenhouse gardening house or for surface coating of a retroreflective sheet.