JPH10330682A - Fluororesin coating agent and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a fluororesin coating agent capable of forming a coating film excellent in chemical and solvent resistances, nontackiness, lubricity, water repellency, etc., and to provide a method for producing the coating agent. SOLUTION: This coating agent is produced by adding an organic solvent having a higher boiling point than the melting point of a terpolymer resin composed of 30-70% tetrafluoroethylene, 10-30% hexafluoropropylene and 10-40% vinylidene fluoride thereto and heating the resultant mixtureat a higher temperature than the melting point of the resin and a lower temperature than the boiling point of the organic solvent and thereby dissolving the resin. Another organic solvent may be added to dilute the resultant solution after dissolving the resin so as to provide a desired resin concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluororesin coating agent excellent in chemical resistance, solvent resistance, non-adhesion, lubricity, water repellency and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, polyethylene tetrafluoride (PT)
Fluorinated resins represented by FE) have high heat resistance, excellent chemical resistance and solvent resistance, and also excellent lubricity and water repellency. Therefore, for example, piping of chemical equipment, gaskets, and oil-free machines It is used in a wide range of fields, such as parts, frying pans, rice cookers, and hot plate inner coatings.

[0003] A coating agent is also known in which a fluorine-based resin is dissolved in an organic solvent so that a coating film can be formed only by evaporating the solvent after coating. However, polyvinyl fluoride, polyvinylidene fluoride, Only a part of the fluorine resin such as a copolymer resin of a fluorine vinyl monomer and a urethane monomer could be applied.

[0004]

However, a conventional fluorine-based resin coating agent obtained by dissolving polyvinyl fluoride, polyvinylidene fluoride, a copolymer resin of a fluorine-based vinyl monomer and a urethane monomer in a solvent, or the like, is not coated. The solvent resistance of the coating film after drying was insufficient. Further, in order to impart solvent resistance, it was necessary to crosslink with isocyanate, phenol resin or the like.

Further, in the case of using a copolymer resin of a fluorine-based vinyl monomer and a urethane monomer, excellent characteristics such as non-adhesiveness and lubricity inherent in the fluorine resin tend to be impaired.

Accordingly, an object of the present invention is to merely evaporate the solvent after coating, and to achieve chemical resistance, solvent resistance, non-adhesion,
An object of the present invention is to provide a fluororesin coating agent capable of forming a coating film having excellent lubricity and water repellency and a method for producing the same.

[0007]

Means for Solving the Problems To achieve the above object, a first aspect of the present invention is to provide 30-70% ethylene tetrafluoride,
A fluorine resin coating agent, wherein a terpolymer resin comprising 10 to 30% of hexafluoropropylene and 10 to 40% of vinylidene fluoride is dissolved in an organic solvent having a boiling point higher than the melting point of the resin. Is provided.

In a second aspect of the present invention, in the first aspect, the terpolymer resin is dissolved in a mixed solvent of an organic solvent having a boiling point higher than the melting point of the resin and another organic solvent. The present invention provides a fluorine resin coating agent.

[0009] A third aspect of the present invention is to provide a polytetrafluoroethylene 30-
An organic solvent having a boiling point higher than the melting point of the terpolymer resin composed of 70%, 10 to 30% of hexafluoropropylene, and 10 to 40% of vinylidene fluoride is added to the terpolymer resin. An object of the present invention is to provide a method for producing a fluororesin coating agent, wherein the resin is dissolved by heating at a temperature lower than the boiling point of the organic solvent.

According to a fourth aspect of the present invention, in the third aspect, an organic solvent having a boiling point higher than the melting point of the terpolymer is added to the terpolymer, and the terpolymer is dissolved by heating to a temperature higher than the melting point of the resin. The present invention provides a method for producing a fluororesin coating agent which is diluted by adding another organic solvent after the addition.

According to the first aspect of the present invention, ethylene tetrafluoride (hereinafter referred to as "TFE"), hexafluoropropylene (hereinafter referred to as "HFP"), and vinylidene fluoride (hereinafter referred to as "VDF") are used. By using a ternary copolymer resin contained in a specific ratio, the inherent properties of fluororesin such as chemical resistance, solvent resistance, non-adhesion, lubricity, lubricity,
A coating agent dissolved in a solvent can be obtained without impairing water repellency.

In the above ternary copolymer resin, TF
When E is less than 30%, non-adhesiveness and lubricity are impaired, and when it exceeds 70%, it becomes difficult to dissolve in a solvent,
Since the transparency becomes poor and the melting point becomes high, the processing temperature also becomes high. If the HFP is less than 10%, the resin is hard and brittle, and the adhesiveness is reduced. If the HFP is more than 30%, the solvent resistance is reduced. Further, if the VDF is less than 10%, it cannot be solubilized in a solvent, and if it exceeds 40%, the solvent resistance decreases.

According to the second aspect of the present invention, by using a mixed solvent of an organic solvent having a boiling point higher than the melting point of the terpolymer resin and another organic solvent, the amount of the solvent added can be controlled as desired. The coating agent having a desired resin concentration can be obtained by making an appropriate adjustment.

According to a third aspect of the present invention, an organic solvent having a boiling point higher than the melting point of the terpolymer is added, and the mixture is heated to a temperature higher than the melting point of the terpolymer. A fluororesin coating agent that can melt a resin and solubilize it in an organic solvent, thereby forming a coating film with excellent chemical resistance, solvent resistance, non-adhesion, lubricity, and water repellency Can be manufactured.

According to a fourth aspect of the present invention, according to the third aspect, the terpolymer resin is dissolved in an organic solvent having a boiling point higher than the melting point of the terpolymer resin, and then the other organic solvent is dissolved. For example, a normal organic solvent having a lower boiling point than the above can be added to dilute the resin to a desired resin concentration. Thereby, the resin concentration can be adjusted so that the film thickness when applied and dried becomes a desired thickness.

[0016]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, TFE 30 to 7
A terpolymer resin comprising 0%, 10 to 30% of HFP, and 10 to 40% of VDF can be produced by emulsion polymerization using a polymerization initiator similar to a usual fluororesin. The terpolymer resin is already commercially available, for example, "THV Fluoroplastic" (trade name, Sumitomo 3M Limited).

The above ternary copolymer resin has a melting point of 115-18.
At 0 ° C, it has rubber-like flexibility and excellent transparency,
Adhesion with different materials is also good. Also, TFE, HFP,
By changing the mixing ratio of the three components of VDF within the above range, the melting point can be appropriately adjusted.

As the organic solvent having a boiling point higher than the melting point of the terpolymer, ketone solvents such as cyclohexanone and isophorone, and solvents such as n-methylpyrrolidone and dimethylformamide are preferable, and isophorone is particularly preferable. Isophorone has a boiling point of 210 ° C.

As a solvent for dilution added after dissolving the terpolymer resin, for example, organic solvents such as methyl ethyl ketone (MEK), methyl acetate, butyl acetate, methyl isobutyl ketone, and acetone can be used.

By adding the above-mentioned solvent for dilution in addition to the organic solvent having a boiling point higher than the melting point of the terpolymer, the drying of the solvent after the application of the coating agent is promoted to form a coating film. Can be improved.

In producing the coating agent of the present invention, an organic solvent having a boiling point higher than the melting point of the terpolymer is added to the terpolymer, and the terpolymer is heated to a temperature higher than the melting point of the resin and the boiling point of the organic solvent. By heating at a lower temperature, the resin is dissolved. In this case, the amount of the organic solvent added is suitably such that the resin content is preferably 40% or less, more preferably 30% or less.

To the solution obtained by dissolving the terpolymer resin in an organic solvent, an organic solvent for dilution as described above is added as necessary, and the resin concentration is preferably 0.5 to 30%, more preferably By setting the content to 1 to 10%, the coating agent of the present invention can be obtained. In addition, the said resin concentration is 0.
If it is less than 5%, a coating film having a sufficient thickness cannot be formed,
If it exceeds 30%, the viscosity of the coating agent becomes too high,
The smoothness of the coating film tends to be impaired. If the resin concentration is less than 10%, a coating method such as air spray is suitable, and if the resin concentration is 10% or more, a coating method such as silk printing or offset printing is suitable.

The coating agent of the present invention, after application, only evaporates the solvent, has chemical resistance, solvent resistance, non-adhesion, lubricity,
A coating film having excellent water repellency can be formed. Therefore, for example, use in various applications such as coating materials or films for building materials, coating films for various medical devices, intermediate films for safety glass, coating films for filters, coating films for chemicals or fuel equipment, etc. Can be.

[0024]

EXAMPLE In a 1-liter three-necked flask equipped with a heating device, 500 ml of isophorone was placed, and TFE40 was added thereto.
%, HFP 20% and VDF 40% were added to 100 g of a fluororesin composed of a terpolymer resin. The melting point of this fluororesin was 115 ° C.

The three-necked flask was equipped with a stirrer, a condenser, and a thermometer, and heated at 120 ° C., which is higher than the melting point of the fluororesin, for 2 hours with stirring. As a result, a coating agent of the present invention comprising a solution in which the fluororesin was uniformly dissolved in isophorone was obtained. This solution is MEK
It was possible to dilute with an organic solvent such as

The above-obtained fluororesin coating agent of the present invention and a commercially available solvent-soluble fluororesin coating agent (containing a copolymer resin of a fluorovinyl monomer and a urethane monomer as a main component) are used. The substrate was applied by air spray and dried at 25 ° C. for 7 days, and the hardness over time, gloss, stain resistance, water repellency and oil repellency were measured.

As a substrate, a zinc phosphate treated steel sheet (bond # 144 treated, 0.6 mm thick dull) was used.
The hardness over time was measured by JIS K5401 by measuring the hardness of a pencil on which a coating film was damaged. The pencil used is a product name "Uni" manufactured by Mitsubishi Pencil. Gloss is JIS Z8741
Was measured under the condition of 60 ° Gloss. The stain resistance was determined by writing on the surface of the coating film with magic of three colors of red, black and blue, leaving the coated film to stand at 23 ° C. for 24 hours, wiping it off with ethanol, and observing the stain condition after wiping. The evaluation was made based on the following criteria: ×: stains remained clearly, Δ: stains remained,…: stains remained,…: stains were completely removed. The water repellency was evaluated by measuring a water contact angle (an angle of a tangent of water dropped on the coating film). Oil repellency was evaluated by measuring the n-decane contact angle (the angle of the tangent of n-decane hanging on the coating film). Table 1 shows the results.

[0028]

[Table 1]

From the results in Table 1, it can be seen that the fluororesin coating agent of the present invention has a higher hardness of the coating film immediately after application than the commercially available solvent-soluble fluororesin coating agent, and has high gloss, stain resistance, It turns out that it is excellent in water repellency and oil repellency.

[0030]

As described above, according to the present invention,
An organic solvent having a boiling point higher than the melting point of the resin is added to a terpolymer resin composed of a specific ratio of TFE, HFP and VDF, and heated at a temperature higher than the melting point of the resin and lower than the boiling point of the organic solvent. By doing so, it became possible to dissolve the resin, which is usually insoluble in the organic solvent, in the solvent. The fluororesin coating agent of the present invention thus obtained can form a coating film excellent in chemical resistance, solvent resistance, non-adhesion, lubricity, and water repellency only by evaporating the solvent after application. it can.

Claims (4)

[Claims] An organic solvent in which a terpolymer resin comprising 30 to 70% of ethylene tetrafluoride, 10 to 30% of hexafluoropropylene and 10 to 40% of vinylidene fluoride has a boiling point higher than the melting point of the resin. A fluorine resin coating agent characterized by being dissolved in water. 2. The fluororesin coating agent according to claim 1, wherein the terpolymer resin is dissolved in a mixed solvent of an organic solvent having a boiling point higher than the melting point of the resin and another organic solvent. 3. An organic solvent having a boiling point higher than the melting point of a terpolymer resin comprising 30 to 70% of ethylene tetrafluoride, 10 to 30% of hexafluoropropylene, and 10 to 40% of vinylidene fluoride. And heating the mixture at a temperature not lower than the melting point of the resin and lower than the boiling point of the organic solvent to dissolve the resin. 4. An organic solvent having a boiling point higher than the melting point of the terpolymer resin is added to the ternary copolymer resin, and the terpolymer resin is dissolved by heating to a temperature higher than the melting point of the resin. The method for producing a fluororesin coating agent according to claim 3, wherein