JPH0596684A - Fluorine polymer covering and production thereof - Google Patents

Abstract

PURPOSE:To provide a fluorine polymer covering which imparts water-repellent and noncohesive properties to the surface of glass without losing the transparency of the glass base material considerably and which has a high adhesiveness to the glass surface and heat resistance. CONSTITUTION:The fluorine polymer covering consists of a glass base material and a mixture of fluororubber and fluororesin coated thereon. It is produced by a method wherein a dispersion type coating material consisting of a particulate mixture of fluororubber and fluororesin and the cross-linking agent is applied on the glass base material and this coat is heated to be dried, so that the rubber is cross-linked and the resin is sintered.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fluoropolymer coating which imparts water repellency and non-adhesiveness to the glass surface without significantly losing the transparency of the glass, and has strong adhesion and heat resistance. The present invention relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, as a water-repellent, non-tacky article using a fluoropolymer, a fluorocarbon resin is coated on a metal substrate such as aluminum or stainless steel through a primer containing a binder such as polyamideimide. Things are common,
It is often used in kitchen applications such as frying pans, hot plates, and jar rice cooker inner pots. Particularly when aluminum is used as a base material, a method is often used in which a fluorine resin is physically adhered to the surface of the aluminum by providing fine irregularities by etching or the like without using such a primer.

As a coating for glass, a frying pan made of glass or a pot made of glass in which the cooking surface is coated with a fluororesin is commercially available. Both are black or dark brown coating, which is a feature of glass. It was a loss of transparency. Perhaps because of this problem, the fluororesin coating of the product group is limited to the bottom or side surface of the glass frying pan or pan, which is relatively lower than the side surface, and the side surface that allows the cooked food to be seen through from the outside. There is no coating on the upper part or the lid. Therefore, the washability of these cooking utensils was insufficient.

On the other hand, as a transparent coating on glass, a silicone or acrylic resin coating is often used for the purpose of protecting the glass surface and preventing scattering of fragments at the time of breakage.
These polymers are insufficient in water repellency and non-adhesiveness.
Also, the coatings for the windshields of automobiles were wax-like temporary. In other words, the present situation is that no fluorine coating has been developed that imparts water repellency and non-adhesiveness to the glass surface without significantly losing the transparency of the glass, and has strong adhesion and heat resistance.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a coating material that imparts water repellency and non-adhesiveness to the glass surface without significantly impairing the transparency of the glass substrate, and has strong adhesion and heat resistance. And a manufacturing method thereof, such as glass frying pans, glass pots, kitchen supplies such as window materials such as microwave ovens and oven toasters, home appliances, office equipment such as copier toner boxes, telephone boxes. Window materials, building materials such as windows for high-rise buildings, automobile side mirrors, automobile traffic safety equipment such as mirrors installed at intersections,
It aims to solve problems in a wide range of fields that require transparency, water repellency, non-adhesiveness, adhesion, or heat resistance, such as cladding or coating of optical fiber cables. Needless to say, the present invention is also effective in applications in which transparency is not particularly important, such as coating on glass cloth.

[0006]

The first invention of the present application is a fluoropolymer coating characterized in that a mixture of fluororubber and fluororesin is coated on a glass substrate.

At least the following is included as an embodiment of the first invention of the present application. (A) The fluoropolymer coating of the first invention, wherein the fluororubber is a VdF-HFP-TFE terpolymer.

(B) The fluoropolymer coating of the first invention, wherein the fluororesin substantially contains FEP.

(C) The mixture of fluororubber and fluororesin is P
The fluoropolymer coating of the first invention, characterized in that it comprises 25% by weight or more and 90% by weight or less of FA or PTFE or a mixture of PFA and PTFE.

(D) The fluoropolymer coating of the first invention, characterized in that the outermost layer is coated with a fluororesin.

The second invention of the present application relates to a manufacturing method for obtaining the first invention, wherein a dispersion type coating material comprising a fine particle mixture of fluororubber and fluororesin and a cross-linking agent is applied onto a glass substrate, This is a method for producing a fluoropolymer coating, which comprises drying by heating, rubber cross-linking, and resin sintering.

Note that at least the following is included as an embodiment of the second invention of the present application. (A) VdF-HFP-TFE as fine particles of fluororubber
The method for producing a fluoropolymer coating according to the second aspect of the present invention, which comprises blending a terpolymer latex to prepare a dispersion type coating material.

(B) A method for producing a fluoropolymer coating of the second invention, characterized in that at least FEP dispersion or powder is blended as the fluororesin fine particles to prepare a dispersion type coating material.

(C) As the fluorine resin fine particles, PFA, PTFE, a mixture of PFA and PTFE, a dispersion, a powder, or a mixture of a powder and a dispersion is mixed to prepare a dispersion type paint, and PFA, P
The weight ratio of TFE or the mixture of PFA and PTFE in the solid content of the dispersion type paint is 25% by weight or more and 90% by weight or more.
The method for producing a fluoropolymer coating of the second invention, characterized by the following.

(D) A dispersion-type paint comprising a fine particle mixture of fluororubber and a fluororesin and a cross-linking agent is applied on a glass substrate, and at least dried and rubber-crosslinked by heating, and then the fluororesin is further coated thereon. The method for producing a fluoropolymer coating of the second invention is characterized in that the sintering is completed by heating.

(E) A method for producing a fluoropolymer coating of the second invention, characterized in that a polyamine-based crosslinking agent is used as a crosslinking agent for the fluororubber.

The present invention will be described in detail below.

The glass substrate used in the present invention includes soda lime glass, phosphosilicate glass, borosilicate glass,
Silicate glass such as borosilicate low-alkali glass, and quartz glass such as lead glass, barium glass, and fluorine glass are representative, but are not particularly limited.
Also, those that have been strengthened by quenching can be used without any problems.

These glasses may be used as they are, or may be roughened by etching, blasting or the like. However, in the present invention, it is not necessary to improve the adhesive strength by roughening. Since the adhesive strength of the coating film can be obtained, even if roughening is performed, it should be kept within a range where the transparency is not significantly lost when the coating is completed. When coating glass, it is necessary to degrease and clean the surface with a solvent or alkali.

As the fluororubber, a binary copolymer (VdF-HFP) of VdF (vinylidene fluoride: chemical formula 1) and HFP (propylene hexafluoride: chemical formula 2), VdF, HFP and TFE are used.
A VdF fluororubber represented by a terpolymer of (tetrafluoroethylene: chemical formula 3), a copolymer of TFE and P (propylene: chemical formula 4), and TFE-P in which a third component is introduced. −
TFE-P type fluororubber represented by P type terpolymer, TFE-perfluoroalkyl vinyl ether type fluororubber, fluororubber (A) and fluororesin (B) are BAB
Thermoplastic fluororubber, fluorosilicone rubber, fluorophosphazene rubber, nitroso rubber, fluorine-containing triazine elastomer, etc. used as a block copolymer are used.

[0020]

[Chemical 1]

[0021]

[Chemical 2]

[0022]

[Chemical 3]

[0023]

[Chemical 4]

These are used as rubber latex or emulsion, or mixed with the fluororesin particles in a solution state, and particularly preferably used as rubber latex because a uniform mixture can be easily obtained.

As the crosslinking agent, a polyamine-based, polyol-based or peroxide-based crosslinking agent is appropriately selected and used. Among them, it is particularly preferable to use a terpolymer of VdF-HFP-TFE with a polyamine-based cross-linking agent, in view of physical properties and processability. A commercially available curing agent is used per 100 parts by weight of a commercially available rubber latex. It is preferable to use 1 to 20 parts by weight of (aqueous solution of polyamine).

These cross-linking agents are not always essential components, and they can be cross-linked by radiation after coating and drying the coating material. It is also possible to combine radiation crosslinking and crosslinking agent crosslinking.

As the fluorine resin, PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), F
EP (tetrafluoroethylene-hexafluoropropylene copolymer), ETFE (tetrafluoroethylene-
(Ethylene copolymer), CTFE (polychlorotrifluoroethylene), PVdF (polyvinylidene fluoride) and their copolymers are used in the form of powder or dispersion dispersed in a rubber latex, emulsion or rubber solution.

Among them, FEP, ETFE, CTFE, PV
By blending at least one component of dF, higher adhesive strength can be obtained, and FEP is particularly preferably used.

For the purpose of increasing the heat resistance of the whole,
25% by weight or more of PFA or PTFE or a mixture thereof in the solid content of a mixture of fluororubber and fluororesin 9
It is preferably compounded in the range of 0% by weight or less. If it is more than 90% by weight, the effect of improving the adhesive strength by fluorine rubber or fluorine rubber and FEP becomes insufficient (see Fig. 1), and 25% by weight
In the following, since the transparency and the water repellency, which is an index of non-adhesiveness, that is, the contact angle with water is reduced (see FIGS. 2 and 3),
The above-mentioned 25 to 90% by weight is a more preferable range.

After the mixture of fluororubber and fluororesin is applied on the glass substrate, it is dried by heating, the rubber is crosslinked, and the resin is sintered, but the heating method and the heat source are not particularly limited. Hot air or a radiant furnace is used. The temperature and time conditions are appropriately selected within the range of conditions generally known to those skilled in the art. Typically, drying at 40 to 80 ° C is performed for 10 to 60 minutes,
After the rubber is crosslinked at 0 to 250 ° C for 5 to 30 minutes, the resin component is sintered for 300 to 4 after the post cure.
It is carried out at 30 ° C. for 5 to 30 minutes.

It is more preferable to further coat the outermost layer with a fluororesin from the viewpoint of non-adhesiveness and heat resistance. The fluororesin used for this purpose is the same as the fluororesin described above. Particularly, PFA and PTFE are preferably used from the viewpoint of heat resistance.

When the outermost layer is coated, it is essential that at least the mixture of the fluororubber and the fluororesin applied as the first layer has the drying step completed, and preferably the rubber crosslinking step is completed. It is good to have However, the resin may be partially or entirely sintered.

[0033]

EXAMPLES The present invention will now be described with reference to examples. Examples 1 to 4 and Comparative Examples 1 to 3 Sheet glass (float glass made by Central Glass: Table 1) was subjected to a strengthening treatment, and the surface thereof was thoroughly degreased with MEK (methyl ethyl ketone), and then the mixture ratios shown in Table 2 were prepared. The fluoropolymer dispersion was applied to a thickness of about 30μ, left at room temperature for about 10 minutes, dried at 60 ° C for 30 minutes, and rubber crosslinked at 250 ° C for 5 minutes, then at 340 ° C.
The resin was sintered for 5 minutes. An average coating film of about 15μ was obtained.

[0034]

[Table 1]

[0035]

[Table 2]

The fluoropolymer coating thus obtained was subjected to an initial evaluation of the adhesive strength, transparency, contact angle with water between the glass substrate and the coating film, and evaluation after the heat aging test. The results are shown in Table 2 and FIGS.

Evaluation Method (Peeling Strength) A commercially available FEP sheet was heat-sealed on the surface of the coating film, and peeled in a direction of 180 ° with a width of 1 cm, and the peeling force at that time was peeling strength (unit: kg / cm). And

(Cross-cut test) JIS on the coated surface
Make a grid 100 stipulated in K 5400-1990, 8.5. 2 and stick cellophane tape (Nichiban Co., Ltd.) sufficiently to this surface and immediately peel it off. This peeling is performed 40 times with a new cellophane tape, and 100 pieces of the tape are evaluated to evaluate how much remains.

(Visible light transmittance) 400 to 700 using a UV / visible spectrophotometer (U-3400 manufactured by Hitachi, Ltd.)
Ratio of integral values of visible light transmittance of nm (1
00%. ) Is the visible light transmittance. The transmittance of the glass plate used as the base material was 90%.

(Contact angle to water) Using a contact angle meter manufactured by Kyowa Interface Science Co., Ltd., the contact angle to water with respect to pure water is determined by the droplet method.

(Initial value and heat aging) Initial value: evaluation value after coating film heat aging: evaluation value after heat history at 250 ° C./24 hr

(Comprehensive Evaluation) The practical adhesive strength was about 0.
It is estimated that an adhesive force of 5 kg / cm or more is required, and that the visible light transmittance at a film thickness of about 15 μ, which is estimated to be the minimum required, is a sensitivity test (one in the 20s and one in the 30s). Approximately 50% or more of the boys were 1 and the boys were in the 40s and the girls in the 20s were 3). Therefore, those who clear this were judged to have good overall evaluation.

[0043]

As described above, according to the present invention, water repellency and non-adhesiveness are imparted to the glass surface without significantly deteriorating the transparency of the glass substrate, and the strong adhesion and heat resistance are imparted. Since it is possible to obtain a coating having, it is possible to use glass frying pans, glass pots, kitchen supplies such as window materials such as microwave ovens and oven toasters, home appliances, office equipment such as copier toner boxes, telephone box window materials, Building materials such as high-rise building window materials, automobile side mirrors, automobile traffic safety equipment such as mirrors installed at intersections, optical fiber cable clads or coatings, etc. are required to have water repellency, non-adhesiveness, adhesiveness or heat resistance. It can be applied to a wide range of fields. Needless to say, the present invention can be effectively applied to applications in which transparency is not particularly important, such as coating on glass cloth.

[0044]

[Brief description of drawings]

FIG. 1 is a graph showing characteristic data of Examples and Comparative Examples of the present invention, showing peel strength of a coating film from a glass substrate.

FIG. 2 is a graph showing characteristic data of Examples of the present invention and Comparative Examples, showing visible light transmittance of coatings.

FIG. 3 is a graph showing characteristic data of Examples and Comparative Examples of the present invention, and shows a contact angle of water on the surface of a coating film.

Claims (2)

[Claims] 1. A fluoropolymer coating characterized in that a mixture of fluororubber and fluororesin is coated on a glass substrate. 2. A dispersion type coating material comprising a fine particle mixture of fluororubber and a fluororesin and a crosslinking agent is applied on a glass substrate,
A method for producing a fluoropolymer coating, which comprises drying by heating, rubber cross-linking, and resin sintering.