JPH10130539A - Water-repellent material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject material which can demonstrate excellent water repellency, waterproofness, resistance to snow and ice accretion and lubricity by dispersing fluororesin particles and photocatalyst particles in the matrix resin. SOLUTION: This material is prepared by dispersing (A) particles of fluororesin and (B) particles of photocatalyst in (C) the matrix resin. As the component C, a fluororesin is preferred because it has particularly high durability to the photodegradation. The component A is preferably particles of fluorine resin having the polymerization units based on a 2-3C fluoro-monomer as in the fluororesin used in the component C. The total formulation of the component A and the component B to the component C is preferably 5-90vol.%. The proportions of the component A and the component B based on the total of both components is preferably 5-95wt.% and 95-5wt.%, respectively. Thus, the water-repellent faces are always renewed by disintegration of the matrix rein with time thereby realizing so-called self-revival type water-repellent material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to water repellency, waterproofness,
The present invention relates to a water-repellent material having excellent durability such as ice and snow resistance and lubricity.

[0002]

2. Description of the Related Art In towers, cables, and antennas in snowfall areas, functions may be impaired by icing snow, or they may be destroyed by weight, and maintenance in winter requires a great deal of manpower. If a material having excellent water repellency and icing and snowing properties is developed, the icing and snowing properties of the article can be prevented, and maintenance-free operation becomes possible. For this reason, attempts have been made to develop a water-repellent material having such characteristics.

[0003]

However, the water repellent materials developed so far have the following disadvantages. For example, water-repellent paints and modified fluororesin-based water-repellent materials, in which a modified metal-based resin having a contact angle of water of about 120 degrees is used as a matrix and a special metal compound is mixed and dispersed in the matrix, have been developed. Consideration was given to the difficulty of icing and snow. Further, a glass fiber reinforced tetrafluoroethylene resin sheet having a contact angle of water of about 108 degrees is used as a hard-to-adhere material for a communication antenna radome.

[0004] However, these water-repellent materials have a problem in that when dirt such as dust scattered in a natural environment adheres to the surface thereof, the hard-to-ice and snow effect is significantly reduced. SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and to provide a material having excellent water repellency, waterproofness, anti-icing and snow resistance, lubricity, and the like.

[0005]

According to the present invention, there is provided a water-repellent material comprising a matrix resin in which fluororesin particles and photocatalyst particles are dispersed.

The matrix resin used in the water-repellent material of the present invention includes acrylic silicone resin, polyester resin, epoxy resin, acrylic resin, urethane resin,
One or more resins selected from phthalic resins, fluororesins, vinyl resins, and the like are included. In particular, a fluororesin is preferred from the viewpoint of durability against photolysis. The number average molecular weight of the matrix resin is usually from 3,000 to 1,000,000, preferably from 5,000 to 500,000.

When the matrix resin is a fluororesin, in order to disperse the fluororesin particles in the fluororesin matrix, the fluororesin matrix and the fluororesin particles are not compatible with each other in producing the water-repellent material of the present invention. Is selected from

A preferred combination of the fluororesin matrix and the fluororesin particles is a case where the fluororesin matrix is a solvent-soluble fluororesin and the fluororesin particles are a solvent-insoluble fluororesin.

When both the fluororesin matrix and the fluororesin particles are solvent-insoluble fluororesins, a fluororesin having a glass transition temperature or melting point higher than that of the fluororesin matrix is selected. The fluororesin particles can also be dispersed in the fluororesin matrix at a temperature lower than the glass transition temperature or melting point of the resin particles and higher than the glass transition temperature or melting point of the fluororesin matrix.

As the fluororesin of the matrix, a fluororesin having a polymerized unit based on a fluoroolefin having 2 to 3 carbon atoms such as tetrafluoroethylene, chlorotrifluoroethylene, hexafluoroethylene, vinylidene fluoride and vinyl fluoride is preferable. . For example, a vinylidene fluoride resin, a fluoroolefin vinyl ether-based copolymer resin, a fluoroolefin-vinyl ester-based copolymer resin, and the like can be given.

As the fluororesin particles, particles made of a fluororesin having a polymerization unit based on a fluoroolefin having 2 to 3 carbon atoms similar to the fluororesin used in the matrix resin can be used.

For example, particles made of fluororesins such as tetrafluoroethylene resin, vinylidene fluoride resin, ethylenetetrafluoroethylene copolymer resin, and perfluoroalkoxy resin are exemplified, and particles made of tetrafluoroethylene resin are particularly preferable.

The number average molecular weight of the fluororesin as particles is
It is usually 500 to 500,000, preferably 1,0.
00 to 100,000. The number average molecular weight of the particles composed of the tetrafluoroethylene resin is usually 500 to 2
000, preferably 1,000 to 10,000.
0.

The total compounding ratio of the fluororesin particles and the photocatalyst particles in the matrix resin is preferably 5 to 90 vol%, more preferably 30 to 90 vol%. If the mixing ratio of the fluororesin particles and the photocatalyst particles is too small, the water repellency and the photolytic effect are poor, which is not preferable. If the blending ratio of the fluororesin particles is too large, sunlight is blocked by the fluororesin particles, and the collapse of the matrix resin is delayed, and the self-resuscitation of the water-repellent effect is undesirably delayed.

The ratio of the former to the total of the fluororesin particles and the photocatalyst particles is preferably such that the former is 5 to 95 vol%, the latter is 5 to 95 vol%, more preferably the former is 20 to 80 vol%, and the latter is 5 to 95 vol%. 20-80vo
1%.

The average particle size of the fluororesin particles in the present invention is preferably from 0.1 to 10 μm, more preferably from 0.5 to 5 μm. The shape of the fluororesin particles is not particularly limited, but a spherical or irregular shape is preferred because it is easily available.

The average particle diameter of the photocatalyst particles in the present invention is preferably 0.01 to 1 μm, and 0.02 to 0.1 μm.
m is more preferred. The shape of the photocatalyst particles is spherical, cylindrical,
Certain shapes such as a cubic shape, a rectangular parallelepiped shape, and a hollow shape are preferable, and a spherical shape is more preferable. The specific gravity of the photocatalyst particles is preferably 3.0 or less, more preferably 2.
5 or less, more preferably 2.0 or less.

The photocatalyst particles mean oxygen-containing compound particles that generate active oxygen by the action of light and water.
The water may be water in the air.

The photocatalyst particles include at least one selected from known photocatalyst particles such as titanium oxide, strontium titanate, tungsten oxide, zinc oxide, and cadmium sulfide. In particular, white titanium oxide which has an excellent photocatalytic function is preferable. In the present invention, the titanium oxide means various titanium oxides such as anatase type titanium oxide, amorphous titanium oxide, metatitanic acid and orthotitanic acid, and hydrous titanium oxide.

The water repellent material of the present invention is preferably used as a coating film forming component of a paint. In this case, a coating liquid comprising the water-repellent material of the present invention is applied to an article by applying a dispersion liquid in which a fluororesin particle that is not dissolved in the organic solvent is dispersed in an organic solvent solution of a matrix resin, and the organic solvent is evaporated. Can be formed.

The surface roughness of the coating film formed from the water repellent material of the present invention is not particularly limited, but the initial water repellency can be increased by setting the surface roughness of the coating film to 1 to 5 μm. is there.

The water-repellent material of the present invention can be used as various molded products including films and sheets. In this case, after kneading the fluororesin particles in the matrix resin at a temperature equal to or higher than the glass transition temperature or the melting point of the matrix resin and lower than the glass transition temperature or the melting point of the fluororesin particles, various types of molding are performed by solidifying and integrating. The body is obtained.

[0023]

The photocatalyst particles represented by the above-mentioned titanium oxide are:
In the natural environment, by the action of sunlight and moisture in the air,
Active oxygen is generated to chemically decompose the matrix resin. The decomposed matrix resin becomes brittle and physically disintegrates due to weather. Therefore, a new water-repellent surface including the fluororesin particles always appears due to the temporal degradation of the matrix resin, so that a so-called self-resuscitation type water-repellent material can be obtained.

[0024]

【Example】

Example 1 Tetrafluoroethylene resin particles having a number average molecular weight of 5,000 (average particle diameter of 1 μm) and titanium oxide particles having an average particle diameter of 0.02 μm are mixed at a volume ratio of 1: 1. Is mixed with a xylene solution of a matrix resin (chlorotrifluoroethylene-alkyl vinyl ether copolymer resin) such that the volume fraction after volatilization of the volatile components becomes 60%, and this water-repellent material is mixed with a fiber-reinforced resin (FR).
P) It was applied on a plate to form a coating film.

The surface of the coating film is blasted to a surface roughness of 1
２2 μm. When a water drop was dropped on this sample and the contact angle was measured, a value of 150 ° was shown. Next, after the sample was exposed outdoors for 3 months, the contact angle was measured, and the value was 145 degrees, and after the exposure was outdoors for 6 months, the value was 150 degrees, indicating that the water repellent effect was maintained. .

Example 2 (Example) Ethylene-tetrafluoroethylene copolymer resin particles having a number average molecular weight of 3,000 (average particle diameter of 1 μm) and titanium oxide particles having an average particle diameter of 0.03 μm were prepared in a volume ratio of 5: 1. And mixed. On the other hand, a xylene solution of a matrix resin (chlorotrifluoroethylene-alkyl vinyl ether copolymer resin) was applied on an FRP plate.

Before the above-mentioned copolymer resin was cured, the above-mentioned particle mixture was sprayed so that the volume fraction after volatilization of the volatile component of the matrix resin became 30%, to obtain a sample having a water-repellent coating film. When a water drop was dropped on this sample and the contact angle was measured, a value of 150 ° was shown. Next, after this sample was exposed outdoors for 3 months, the contact angle was measured.
The value of 0 degree was exposed outdoors for 6 months, and the contact angle was measured. The value was 145 degrees, indicating that the water repellency was maintained.

Example 3 (Example) A xylene solution of an acrylic silicone resin was applied on an FRP plate to obtain an FRP plate having an acrylic silicone resin coating film. On the acrylic silicone resin coating film of the FRP plate, tetrafluoroethylene resin particles having a number average molecular weight of 3000 (average particle diameter of 1 μm) and an average particle diameter of 0.05 μm
The titanium oxide particles are mixed in a volume ratio of 1 to 1,
The mixture of the particles was treated with a volume fraction of 50 after volatilization of volatile components.
% In a xylene solution of a matrix resin (chlorotrifluoroethylene alkyl vinyl ether copolymer resin), and this water repellent material was applied to form a coating film.

When a contact angle was measured by dropping a water drop on this sample, a value of 145 degrees was shown. The sample was then
After a month of outdoor exposure, the contact angle was measured to be 143.
The value of degree showed that the water repellent effect was maintained.

Example 4 (Comparative Example) A matrix resin (chlorotrifluoroethylene-alkyl) was prepared such that tetrafluoroethylene resin particles having a number average molecular weight of 2,000 (average particle diameter of 1 μm) had a volume fraction of 50% after volatilization of volatile components. It was mixed with a xylene solution of a vinyl ether copolymer resin) and applied on an FRP plate to form a coating film.

The surface of the coating film is blasted to a surface roughness of 1
２2 μm. When a water drop was dropped on this sample and the contact angle was measured, a value of 150 ° was shown. Next, after this sample was exposed outdoors for 3 months, the contact angle was measured and found to be a value of 120 °, indicating that the water repellency was reduced. Dust and oil and smoke stains adhered to the sample surface.

Example 5 (Comparative Example) A modified silicone resin water-repellent coating agent was applied on an FRP plate. When a water drop was dropped on this sample and the contact angle was measured, it showed a value of 110 degrees. Next, after this sample was exposed outdoors for 3 months, the contact angle was measured.
It showed a value of 0 degrees, indicating that the water repellency was reduced. Dust and oil and smoke stains adhered to the sample surface.

[0033]

By using titanium oxide particles mixed with a matrix resin together with fluororesin particles, a so-called self-resuscitation type water-repellent material which always shows a new water-repellent surface due to the time-dependent collapse of the matrix resin. can do.

Claims (5)

[Claims] 1. A water-repellent material comprising a matrix resin in which fluororesin particles and photocatalyst particles are dispersed. 2. The water-repellent material according to claim 1, wherein the total mixing ratio of the fluororesin particles and the photocatalyst particles in the matrix resin is 5 to 90 vol%. 3. The method according to claim 1, wherein the ratio of the former to the total of the fluororesin particles and the photocatalyst particles is such that the former is 5 to 95 vol% and the latter is 5 to 95 vol%.
Water repellent material. 4. The fluororesin particles and the photocatalyst particles have an average particle diameter of 0.1 to 10 μm and 0.01 to 1, respectively.
The water-repellent material according to any one of claims 1 to 3, which has a diameter of µm. 5. The photocatalyst particles are titanium oxide.
4. The water repellent material according to any one of 4.