JP2001164064A - Dispersion composition of fluorine containing meltable resin and coated product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dispersion composition of fluorine containing meltable resin capable of forming a membrane having an affinity to silicone oil in spite of the membrane is formed from a fluororesin. SOLUTION: This dispersion composition of a fluorine containing meltable resin comprises the fluorine including meltable resin having average particle size of 5-1,000 μm and a liquid medium formulated with a material having affinity to silicone oil and/or a material capable of forming a silicone oil absorbing gap in a coated membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorine-containing molten resin dispersion composition and a coated article, and more particularly, to a substance capable of forming a silicone oil-philic substance and / or a silicone oil-adsorbing void in a coating film. The present invention relates to a dispersion composition of a fluorine-containing molten resin capable of being melt-molded and an article having a film formed from such a composition.

[0002]

2. Description of the Related Art Silicone rubber is generally used as a roll base material used in office automation (OA) equipment (for example, copying machines, printers, etc.). A silicone oil may be applied to the surface of such a roll for OA equipment in order to impart durability and non-adhesion. For the same purpose, a film may be formed from a fluororubber and / or a fluororesin composition. However, the film formed from fluoro rubber or fluoro resin is difficult to get wet with silicone oil.
It was difficult to further improve durability and non-adhesion by using both of these means in combination.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluorine-containing molten resin dispersion composition capable of forming a film having a silicone oil-philic property. Another object of the present invention is to provide an article having a film formed from such a composition, particularly a roll for OA equipment which is easily wetted by silicone oil despite having a surface layer formed from a fluororesin. That is.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to provide a silicone oil-philic substance and / or a substance capable of forming silicone oil-adsorbing voids in a coating film, and having an average particle size of 5 to 100.
The problem is solved by a fluorine-containing molten resin dispersion composition comprising 0 μm of a fluorine-containing molten resin and a liquid medium, and an article whose surface is at least partially coated with a coating layer formed from the composition.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. (A) Fluorine-containing molten resin dispersion composition The fluorinated molten resin contained in the dispersion composition of the present invention is a fluorinated molten resin powder having an average particle size of 5 to 1000 μm. This is a composition obtained by dispersing a fluorine molten resin powder in a liquid medium.

In the case of a solvent-based composition, a solvent having a boiling point of 250 ° C. or less selected from ketones, alcohols, esters, aliphatic hydrocarbons and aromatic hydrocarbons, and a surface activity of 10% by weight or less based on the weight of the solvent. The combination with the agent is used as a medium. However, an aqueous composition is desired in view of recent regulations on solvents and environmental issues. Therefore, the present invention will be described below using an aqueous composition as an example.

(A) Fluorine-containing molten resin As the fluorine-containing molten resin used in the present invention, 150 to 3
Has a melting point of 50 ° C., a melt viscosity at 50 ° C. above the melting point is preferably not more than 10 ⁷ poise. Specific examples include a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), a tetrafluoroethylene-perfluoroalkyl vinyl ether-hexafluoropropylene copolymer (EPA), and a tetrafluoroethylene-ethylene copolymer (ETFE) , A tetrafluoroethylene copolymer such as a tetrafluoroethylene-hexafluoropropylene copolymer (FEP); a polychlorotrifluoroethylene (PCTFE), a chlorotrifluoroethylene-ethylene copolymer (ECTF)
E) and the like; chlorotrifluoroethylene copolymers; polyvinylidene fluoride (PVdF), vinylidene fluoride copolymer, and the like. These fluorinated molten resins can be used alone or in combination of two or more. Among them, a tetrafluoroethylene copolymer is preferable in terms of non-adhesiveness, and PFA is more preferable in terms of heat resistance.

The average particle size of the fluorine-containing molten resin is usually 5 to 5.
It is 1000 μm, preferably 10 to 300 μm, more preferably 15 to 100 μm. If the average particle size is too small, cracks tend to occur in the coating film during firing, so that thick coating cannot be performed. On the other hand, if the average particle size is too large, sedimentation tends to occur in the dispersion composition and the dispersion state is stabilized. Not be able to paint. Preferably, the powder is between 0.3 and 1.5 g / m
1, especially 0.5 to 1.0 g / ml in apparent density. If the apparent density is small, the dispersibility is poor, and the embedment of bubbles and poor leveling property are liable to occur. If it is too large, sedimentation is liable to occur, and the dispersion stability of the composition is deteriorated.

The content of the fluorine-containing molten resin powder is 15 to 80% by weight, preferably 25 to 75% by weight, particularly preferably 30 to 70% by weight, based on the total weight of the composition. If the amount of the fluorine-containing molten resin powder is less than the above lower limit, the viscosity of the dispersion is too low, so that even if it is applied to the surface of an article, sagging occurs immediately, and thick coating cannot be performed. On the other hand, if the blending amount of the fluorine-containing molten resin powder is too large, the composition does not become fluid and cannot be painted. The specific compounding amount may be appropriately selected within the above range in consideration of the coating method and adjustment of the film thickness, etc., but in the case of spray coating, etc., the concentration is relatively low, while in the case of press coating, etc. The content is preferably 50% by weight or more to be a paste.

(B) Water-soluble solvent The aqueous dispersion composition used in the present invention usually contains a water-soluble solvent. The water-soluble solvent has a function of wetting the fluorine-containing molten resin, and those having a high boiling point act as a drying retarder for connecting the resins at the time of drying after coating and preventing the generation of cracks. Even a solvent having a high boiling point evaporates at the sintering temperature of the fluorine-containing molten resin, and does not remain and adversely affect the coating film.

Specific examples of the water-soluble solvent include, for example, methanol as a low-boiling organic solvent having a boiling point of up to 100 ° C.
Ethanol, isopropanol, sec-butanol, t-butanol, acetone, methyl ethyl ketone, etc. 150 ° C
N-methyl-2-pyrrolidone as the above high boiling organic solvent,
N, N-dimethylacetamide, N, N-dimethylformamide, ketocin, ethylene glycol, propylene glycol, glycerin, dimethyl carbitol, butyl dicarbitol, butyl cellosolve, cyclohexanol, diisobutyl ketone, 1,4-butanediol, triethylene glycol And tetraethylene glycol. As the high-boiling organic solvent, an alcohol solvent is preferable in terms of wettability and safety of the fluorine-containing molten resin.

The compounding amount of the water-soluble solvent is 0.5 to the total water amount.
It is 50% by weight, preferably 1 to 30% by weight. In the case of a low-boiling organic solvent, if the amount is too small, bubbles are likely to be entrapped, and if the amount is too large, the entire composition becomes flammable and the advantage of the aqueous dispersion composition is impaired. In the case of a medium-boiling organic solvent, if the amount is too large, it may remain in the coating film even after baking and adversely affect.If the amount is too small, the fluorine-containing molten resin returns to a powder upon drying after coating and is baked. Can not. In the case of a high boiling point organic solvent, if the compounding amount is too large, it may remain on the coating film even after firing and adversely affect the coating.

(C) Surfactant The surfactant is prepared by adding 15 parts of the fluorine-containing molten resin powder to the composition.
What is necessary is just to be able to be uniformly dispersed at ~ 80% by weight,
Any of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant can be used. For example, anionic surfactants such as sodium alkyl sulfate, sodium alkyl ether sulfate, triethanolamine alkyl sulfate, triethanolamine alkyl ether sulfate, ammonium alkyl sulfate, ammonium alkyl ether sulfate, sodium alkyl ether phosphate, sodium fluoroalkylcarboxylate, etc. Agents; cationic surfactants such as alkyl ammonium salts and alkyl benzyl ammonium salts; polyoxyethylene alkyl ether, polyoxyethylene phenyl ether, polyoxyethylene alkyl ester, propylene glycol-propylene oxide copolymer, perfluoroalkyl ethylene oxide addition Substance, 2-ethylhexanol ethylene oxide Nonionic surfactants such as adducts; amphoteric surfactants such as betaine alkylaminoacetate, betaine alkylamidoacetate, and imidazolium betaine; In particular, anionic and nonionic surfactants are preferred. Particularly preferred surfactants are nonionic surfactants having an oxyethylene chain with low thermal decomposition residue.

The amount of the surfactant to be added is usually 0.01 to 50% by weight, preferably 0.1 to 3% by weight of the fluorine-containing molten resin powder.
0% by weight, particularly preferably 0.2 to 20% by weight.
If the addition amount of the surfactant is too small, the dispersion of the fluorine-containing molten resin powder may not be uniform and may partly float.
On the other hand, if the addition amount of the surfactant is too large, the decomposition residue of the surfactant due to baking increases, coloring occurs, and the heat resistance, non-adhesiveness, etc. of the coating film decrease.

(D) Additives Various additives can be added to the dispersion composition of the fluorine-containing molten resin powder used in the present invention depending on the use. Examples of the additive include a filler, a stabilizer, a pigment, a thickener, a decomposition accelerator, a rust inhibitor, an antifoaming agent, and the like.

The aqueous dispersion composition used in the present invention can be prepared by uniformly dispersing the fluorine-containing molten resin powder in water, preferably pure water, in the presence of a water-soluble solvent and a surfactant. On the other hand, a solvent-based dispersion composition using a solvent having a low surface tension may not require water and a surfactant.

In a conventional general fluorine-containing molten resin-dispersed coating material, the resin particle size in the coating material is as small as about 0.2 to 0.6 μm, so that the thickness of the coating film formed by one coating is small. 2
If it exceeds 0 μm, cracks are likely to occur. Even if the number of firing times of coating is increased to increase the thickness of the coating film, cracks are more likely to occur as the film thickness increases. However, when the composition used in the present invention is used, a coating film having a thickness of about 100 μm can be easily obtained by one coating without generating cracks. This composition is blended with a silicone oil-philic substance and / or a substance capable of forming a silicone oil-adsorbing void in a coating film as described in the following (B), so that the silicone oil-philic substance is added to the coating layer formed. Properties can be imparted.

(B) Silicone-lipophilic substance and substance capable of forming silicone oil-adsorbing voids in the coating film.
Examples include silicone oil and silicone rubber powder suspension. For silica colloid, silicone oil, and silicone rubber powder suspension, it is necessary that decomposition residues remain after firing the fluorinated molten resin dispersion composition. It is considered that these decomposition residues have an affinity for silicone oil. When the fluorinated molten resin dispersion composition is an aqueous composition, it must be water-soluble.

On the other hand, as a substance capable of forming a silicone oil-adsorbing void in the coating film, a resin having a melting point higher than the melting point of the fluorine-containing molten resin and having an affinity for the fluorine-containing molten resin, for example, a non-melting resin Fluororesin, preferably polytetrafluoroethylene (PTFE), modified PTFE
Etc. can be used. Since such a non-melting fluororesin does not completely melt by firing, voids are formed inside or on the surface of the coating film, and the voids adsorb the silicone oil on the surface of the coating film. It is thought that it becomes easier to get wet.
Substances capable of forming silicone oil-adsorbing voids in the coating film are usually incorporated into the composition as a dispersion.

The mixing ratio of silica colloid or silicone oil is based on 100 parts by weight of the fluorine-containing molten resin.
0.001 to 10 parts by weight, preferably 0.01 to 1 part by weight. The mixing ratio of the silicone rubber powder suspension is 0.01 to 100 parts by weight of the fluorine-containing molten resin.
100 parts by weight, preferably 0.1 to 50 parts by weight.
The compounding ratio of a substance capable of forming a silicone oil-adsorptive void in the coating film, for example, PTFE, is as follows.
The amount is 0.01 to 100 parts by weight, preferably 0.1 to 50 parts by weight, based on 00 parts by weight. If the amount is less than the above lower limit, the resulting coating film will have low silicone oil-philicity, while if it exceeds the upper limit, the surface smoothness of the coating film may be lost. These substances may be used alone or in combination of two or more. When used alone, any of the above-mentioned silicone oil-based substances is used, and when two or more kinds are used in combination, two or more kinds of the above-mentioned silicone oil-based substances, or silicone oil-based substances are used. It is preferable to use a substance capable of forming the silicone oil-adsorbing void in the coating film.

The coating formed from the composition of the present invention is formed on the surface of an article made of a heat-resistant rubber such as fluororubber or silicone rubber, and is required to have heat resistance, solvent resistance, lubricity and non-adhesion. Can be used in the field. Main applications include rolls for OA equipment such as copiers, printers, and facsimile machines (eg, fixing rolls, pressure rolls), but also include transport belts; sheets and belts;
It can also be used for O-rings, diaphragms, chemical resistant tubes, fuel hoses, valve seals, gaskets for chemical plants, engine gaskets, and the like.

[0022]

The present invention will be described below in detail with reference to examples. Example 1 Preparation of fluorinated molten resin dispersion composition: 4 parts by weight of isopropyl alcohol, 8 parts by weight of nonionic surfactant (perfluoroalkylethylene oxide adduct), 6 parts by weight of triethylene glycol, 4 parts by weight of ethylene glycol, 20 parts by weight of pure water, PFA resin powder (average particle size 25 μ
m, apparent density 0.8 g / ml) 26 parts by weight, silica colloid (Snowtex 30 manufactured by Nissan Chemical Industries, Ltd.)
0.16 parts by weight were mixed and dispersed to prepare a uniform dispersion composition.

Formation of a coating film: On the surface of the silicone rubber sheet, a functional group-containing PFA dispersion as a primer (hydroxyl group-containing PFA described in Production Example 1 of WO98 / 50229, solid content concentration 10.9%, particle size 70.
7 nm), dried at 80-100 ° C for 30 minutes, and baked at 300 ° C for 15 minutes. in addition,
The fluorinated molten resin dispersion composition prepared above is spray-coated, dried at 80 to 100 ° C. for 15 minutes, and then 340 ° C.
For 30 minutes to form a coating film having a thickness of about 30 μm.

Evaluation of silicone oil-philicity of coating film: One drop of silicone oil (SH200-5, manufactured by Toray Dow Corning Silicone Co., Ltd.) was dropped on the surface of the obtained coating film, and a goniometer (Kyowa Interface Science Co., Ltd.) was used. ) Was measured.

Example 2 The procedure of Example 1 was repeated except that 0.05 parts by weight of silicone oil (SH3746, manufactured by Toray Dow Corning Silicone Co., Ltd.) was used instead of silica colloid during the preparation of the fluorine-containing molten resin dispersion composition. Repeated.

Example 3 When preparing a fluorine-containing molten resin dispersion composition, a silicone rubber powder suspension (DY33-4 manufactured by Dow Corning Toray Silicone Co., Ltd.) was used instead of silica colloid.
40F) The procedure of Example 1 was repeated except that 3.9 parts by weight were blended.

Example 4 In preparing a fluorine-containing molten resin dispersion composition, PTFE dispersion (molecular weight of about 500
The procedure of Example 1 was repeated except that 4.3 parts by weight (2.6 parts by weight as PTFE solids) were blended.

Example 5 When preparing a fluorine-containing molten resin dispersion composition, a PTFE dispersion (molecular weight of about 50) was used instead of silica colloid.
Example 1 was repeated except that 6.0 parts by weight (3.6 parts by weight as PTFE solids) were added.

Example 6 In preparing the fluorine-containing molten resin dispersion composition, PTF was further added.
The procedure of Example 1 was repeated except that 4.3 parts by weight of E dispersion (molecular weight: about 5,000,000) (2.6 parts by weight as PTFE solid content) was added.

Comparative Example 1 The procedure of Example 1 was repeated except that no silica colloid was added during the preparation of the fluorine-containing molten resin dispersion composition.

Table 1 shows the results of the contact angles measured in Examples and Comparative Examples.

[0032]

[Table 1]

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seitaro Terasaka 1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industries, Ltd. Yodogawa Works (72) Inventor Yasutoshi Nakatani 1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industries F-term (reference) in Yodogawa Seisakusho Co., Ltd. NA04 NA10 NA14 PB06

Claims (7)

[Claims] 1. A substance capable of forming a silicone oil-philic substance and / or a silicone oil-adsorbing void in a coating film, a fluorine-containing molten resin having an average particle size of 5 to 1000 μm,
And a fluorine-containing molten resin dispersion composition comprising a liquid medium. 2. The composition according to claim 1, wherein the silicone oil-philic substance is at least one substance selected from the group consisting of colloidal silica, silicone oil, and silicone rubber powder suspension. 3. The composition according to claim 1, wherein the substance capable of forming a silicone oil-adsorbing void in the coating film is a non-melting fluororesin. 4. The composition according to claim 1, wherein the fluorine-containing molten resin dispersion composition is an aqueous dispersion composition. 5. The fluorinated molten resin dispersion composition comprises 5 to 1
A fluorine-containing molten resin powder having an average particle size of 000 μm,
The composition comprises a substance which can form a silicone oil-philic substance and / or a substance capable of forming a silicone oil-adsorbing void in a coating film, water, a water-soluble solvent, and a surfactant. 5 to 80% by weight based on weight
The composition according to claim 1, which is: 6. An article, the surface of which is at least partially covered with a coating layer formed from the composition according to claim 1. Description: 7. The article according to claim 6, which is a roll for office automation equipment.