JPH0372671B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a laminate formed by adhering a fluororesin onto a base material. More specifically, the present invention relates to a fluororesin and base resin having extremely excellent peel resistance, which is characterized by containing a composition consisting of a copolymer resin of tetrafluoroethylene and perfluoroalkyl vinyl ether and a polyimide resin as a primer. The present invention relates to a method for manufacturing a laminate made of materials. Fluorine resin is stable to chemicals, has a small coefficient of friction, and has excellent non-adhesion and heat resistance.
It is used for coating various parts. However, because it has excellent non-adhesive properties, it has poor adhesion to base materials such as metal, glass, or ceramics, and there is a problem in that the fluororesin layer peels off from the base material when used for a long period of time. Many studies have been carried out to improve the adhesion between fluororesins and substrates. For example, the surface of fluororesins is defluorinated using sodium-ammonium complex salts to impart surface adhesion.
Methods have been proposed, including methods for firmly adhering to the base material, and methods for roughening the surface of the base material by physical or chemical means to improve adhesion through an anchor effect, but both proposals are still insufficient. However, it has not yet been possible to impart sufficient adhesion. In view of the current situation, the inventors of the present invention conducted extensive research and discovered a primer composition that firmly adheres the base material and the fluororesin and at the same time is easy to apply. He has perfected the method of manufacturing the body. The gist is that in a method for manufacturing a laminate consisting of a fluororesin and a base material, a copolymer resin of tetrafluoroethylene and perfluoroalkyl vinyl ether and a polyimide resin are preliminarily prepared on the base material in a ratio of 7.5:2.5 to 6.5: This is a method for producing a laminate, characterized in that a primer composition blended at a weight ratio of 3.5 is applied. The copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether used in the present invention can be in the form of powder, granules, aqueous dispersion, organosol, or the like. Specifically, polyimide resins can be produced by the reaction of aromatic tetravalent carboxylic acid anhydrides (pyromellitic anhydride, etc.) and aromatic diamines (diaminodiphenyl ether, etc.), and include Kaptpn, Vespel (and more).
Dupont), Kinel, Kermid (Mitsui Petrochemical Industries), etc. In order to obtain the primer composition used in the method for producing the laminate of the present invention, for example, powdered or granular tetrafluoroethylene and perfluoroalkyl vinyl ether copolymer resin may be added as necessary to improve dispersibility. The powder is further pulverized using a ball mill or the like and dispersed in a liquid medium. In the case of an organosol-in-water emulsion or an aqueous copolymer dispersion obtained by an emulsion polymerization method, they are used as they are. As the liquid medium used to disperse the above-mentioned fluorine copolymer resin and polyimide resin, an organic medium can be used in addition to water. In terms of safety, ease of handling, and effectiveness,
An aqueous medium containing some organic medium that dissolves the synthetic resin having imide bonds is suitable. Examples of the organic medium include N-methylpyrrolidone, cresol, phenol, naphtha, dimethylformamide, dimethylacetamide, benzonitrile, methyl glycol acetate, ethyl glycol acetate, methyl ethyl ketone, ethyl acetate, benzene, toluene, and xylene. The primer composition obtained in this way is
It is necessary that the weight ratio of the fluorine copolymer resin and polyimide resin is in the range of 7.5:2.5 to 6.5:3.5. If it is out of the above range, that is, if the amount of the fluorine copolymer resin is too large or too small, the adhesion between the base material and the fluorine resin will not be good, making it impossible to obtain a laminate with good peel resistance. . Further, various known additives may be added to the primer composition used in the laminate of the present invention. Examples of such additives include fatty acids, sulfuric esters of higher alcohols, alkylbenzenesulfonic acids, alkylnaphthalenesulfonic acids, polynaphthalenesulfonic acids and salts thereof, carboxylic acids having fluoroalkyl groups, sulfonic acids, phosphoric acids, and methyl cellulose, ethyl cellulose, carboxymethyl cellulose. , hydroxyethyl cellulose, wax, etc. as a viscosity modifier, and higher alcohols such as octyl alcohol and cyclohexanol, ethylene glycol, polymethylsiloxane, etc. as antifoaming agents. The base material constituting the laminate produced by the method of the present invention may be made of any material and shape such as metal, glass, ceramic, etc. In order to improve the adhesion with the primer composition, the base material may be sandblasted or
Shot blasting, grit blasting, honing, paper scratching, wire scratching,
Treatments such as hairline treatment and chemical etching may also be applied. In addition, the fluororesin to be bonded to the substrate with the primer composition of the present invention includes not only a homopolymer of tetrafluoroethylene but also a combination of tetrafluoroethylene and hexafluoropropylene, chlorotrifluoroethylene, perfluoroalkyl vinyl ether, etc. Examples include copolymers, polychlorotrifluoroethylene, and mixtures thereof, and the form thereof may be any form such as powder, granules, aqueous or organic dispersion, organosol, and emulsion of organosol in water. Among these fluororesins, the perfluoroalkoxy resin used in the primer composition exhibits stronger adhesive properties. In the production method of the present invention, the primer composition described above is applied onto a substrate whose surface has been roughened by sandblasting or other treatment to a film thickness of approximately 2 to 30 μ on a dry basis, dried, and then fired. Drying and baking conditions for the coated substrate vary depending on the type of solvent used in the substrate and primer composition, but the usual drying conditions are 70℃ to 110℃ for about 5 minutes to 20 minutes, and baking at 200℃. Conditions of 5 minutes to 20 minutes at a temperature of .degree. C. to 380.degree. C. are used. This is coated with the above-mentioned fluororesin paint and fired. Although there are no particular restrictions on the coating method, for example, when using a barfluoroalkoxy resin powder coating, electrostatic coating is recommended. Alternatively, the same or different types of fluororesin may be applied in multiple layers to form multiple layers. The laminate produced by the method of the present invention has extremely excellent peel resistance and is suitably used for various heat-resistant and chemical-resistant containers. Examples will be shown next, but the present invention is not limited to these examples unless the purpose of the invention is impaired. Example 1 Polyimide resin (Kelimide 601), N-methylpyrrolidone and pure water were mixed in equal parts by weight, and the mixture was pulverized and mixed in a ball mill for 24 hours until the average particle size was 5μ.
A dispersion of polyimide resin was prepared. Next, an aqueous dispersion of tetrafluoroethylene and perfluoroalkyl vinyl ether copolymer obtained by emulsion polymerization method (resin content of the copolymer 54 wt%)
and the polyimide resin dispersion liquid in the weight ratio shown in Table 1, and further added 2 parts by weight of 5 wt% methyl cellulose aqueous solution based on the solid content, and added pure water until the total amount of the copolymer and polyimide resin was Adjusted to 35wt%. The sample was applied onto an iron plate roughened by sandblasting (film thickness 5 μm (dry)), dried at 80°C for 10 minutes, and then baked at 280°C for 10 minutes. Furthermore, perfluoroalkoxy resin powder coating (MP-10: Mitsui Fluorochemical) was electrostatically applied and baked (360℃,
10 minutes) was repeated until the thickness was 1 mm to obtain a laminate test piece. Using this laminate test piece, after an automatic tensile test, the topcoat layer was peeled off in a 180 degree direction at a speed of 50 mm/min to measure the adhesive strength. The results are shown in Table 1. It can be seen that the laminate of the present invention has extremely excellent peelability. 【table】

Claims (1)

[Claims] 1. In a method for producing a laminate consisting of a fluororesin and a base material, a copolymer resin of tetrafluoroethylene and perfluoroalkyl vinyl ether and a polyimide resin are preliminarily coated on the base material in a ratio of 7.5:2.5.
A primer composition formulated at a weight ratio of ~6.5:3.5 is applied and baked, and then a fluororesin in the form of powder or dispersion is applied on the primer layer,
A method for producing a laminate, characterized by forming a film by heating a fluororesin.