CN1053915C - Methods for producing fluororesin paint composition, a fluororesin covered plate, and a processed body covered with fluororesin - Google Patents

Abstract

The fluorine-containing resin coating composition is composed of fluorine-containing resin particles or fluorine-containing resin particles and pigment particles dispersed in a surfactant-based dispersant, which can achieve large-area coating on an industrial production scale; and Coating the coating composition on the substrate with a screen coating method, drying and sintering, or further heating the dried and sintered coated plate to press the resin surface; and the compounded plate A method of manufacturing a workpiece that is deformed by stress into an arbitrary shape.

Description

Fluorine-containing resin coating composition, its laminated board, and manufacturing method of laminated product

The present invention relates to a fluorine-containing resin composition, a method for manufacturing a fluorine-containing resin coated sheet, and a method for manufacturing a fluorine-containing resin to be processed, and in particular to a fluorine-containing resin coating composition containing no pigment or a fluorine-containing resin coating composition containing a pigment. The resin coating composition is a method for producing processed products such as rice cooker inner pots by the screen coating method.

Generally, a layer of fluorine-containing tree resin is mostly coated on the surface of the inner pot of the rice cooker, the inner sleeve of the heat preservation pot, and the frying pan. The conventional technique is to apply the fluorine-containing resin coating composition without pigment or with pigment by spraying method (refer to "Introduction to Coating Equipment and Operation Technology" issued by the General Technical Center of Co., Ltd., 2.4.2 2nd edition of level 2) On substrates such as aluminum plates, it is made by drying and sintering. For those containing pigments, it is made by recoating with a fluorine-containing resin paint that does not contain pigments, and then drying and sintering.

However, there are fundamental problems such as spray coating and other coating methods such as coating loss and non-uniform coating film thickness, which make it difficult to obtain a uniform coating film thickness.

On the other hand, the screen printing method (refer to "Introduction to Coating Equipment and Operation Technology" issued by the Comprehensive Technology Center of Co., Ltd., 2.4.2 2nd Edition P197) is widely used in today's printing field. It can be freely painted into various graphics, and it is an effective method that is light, cheap, practical and convenient to install.

However, when the screen printing method is applied to the coating of fluorine-containing resins, corresponding coating materials suitable for the screen printing method are required. Since fluorine-containing resins are generally insoluble in solvents, it is impossible to prepare screen printing paints containing fluorine-containing resins by conventional methods. We have developed a coating and a method for forming a scale pattern on a fluorine-containing resin laminated board by screen printing, and applied for a patent (No. 5-78613).

However, the paint used for scale printing is intended to be used on a relatively thin film, and a large amount of pigments must be blended for coloring, so it cannot be directly applied to the present invention, which intends to form the fluororesin coating itself by applying the screen coating method. content.

In addition, there is Japanese Patent Publication No. 2-61308, which applies a screen printing method to a fluorine-containing resin coating. In this patent, a method of forming a decoration on a polytetrafluoroethylene (PTFE) coated film is disclosed. Specifically, a PTFE water-soluble dispersion is coated on a metal substrate, and after drying and before sintering, a wire mesh is used to A method in which two layers are fired simultaneously after printing a composition containing fluorocarbon powder, etc. However, there is no description about the technique of coating a fluorine-containing resin directly on a metal substrate or on the surface of a sintered fluorine-containing resin.

Also, JP-A-3-217470 describes a method in which an ink mixed with a resin thermally decomposed at 450° C. or less and fluorine-containing resin powder is printed on a metal substrate, and the resin is decomposed by heating. However, in this method, a considerable amount of resin needs to be completely decomposed by heating, so high temperature and long time treatment are necessary. Therefore, no matter how high the heat-resistant fluorine-containing resin is, it is impossible to avoid thermal decomposition during this period, which adversely affects physical properties such as abrasion resistance and non-sticking property.

In addition, any of the above-mentioned methods focus on drawing characters, graphics and other patterns by screen printing to obtain decorative effects, but do not disclose the method of fully covering the substrate with fluorine-containing resin.

The purpose of the present invention is to overcome some problems existing in the industrial production of fluorine-containing resin coatings in the past, and has developed a screen coating method using screen printing (hereinafter referred to as a screen coating method in this specification) to cover a large area. Furthermore, it is a technique to apply fluorine-containing resin or pigment-containing fluorine-containing resin to almost the entire surface.

In order to achieve the above objects, the first invention is a fluorine-containing resin coating composition for screen coating, which is characterized in that fluorine-containing resin particles are dispersed in a dispersant mainly composed of a surfactant and does not contain pigments. The aforementioned "surfactant-based" means that the amount of the surfactant in the dispersant is more than half (hereinafter also the same meaning in this specification). Furthermore, an embodiment of the first invention of the present application includes at least the following.

(1) The above-mentioned fluorine-containing resin coating composition for screen coating of the first invention of the present application is characterized in that the surfactant is substantially composed of alkyl groups and alkylene oxides, and does not contain aromatic rings, carbon-carbon The heavy bond between them is only a nonionic surfactant with a chemical structure composed of carbon, hydrogen, and oxygen atoms.

In addition, the surfactant in this embodiment is limited to the surfactant of the main component, but it does not exclude a small amount of other surfactants added for defoaming and surface tension reduction (the same applies to the following).

(2) The above-mentioned fluorine-containing resin coating composition for screen coating according to the first invention of the present application is characterized in that the fluorine-containing resin particles are PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer).

(3) The above-mentioned fluorine-containing resin coating composition for screen coating according to the embodiment (2) of the first invention of the present application is characterized in that the fluorine-containing resin particles are spherical PFA particles with an average particle diameter of 10-30 μm and, A mixture of PFA particles with a lower molecular weight than PFA and an average particle size of 10 μm or less.

The second invention of the present application is a fluorine-containing resin coating composition for screen coating, which is characterized in that the fluorine-containing resin and pigment particles are dispersed in a dispersant mainly composed of a surfactant, and the surfactant is essentially only It is composed of alkyl and oxyalkylene, does not contain aromatic rings, carbon-carbon heavy bonds, and is a non-ionic surfactant with a chemical structure composed of carbon, hydrogen, and oxygen atoms.

In the first invention of the present application, the surfactant can be selected within a relatively wide range. But for the second invention, due to the existence of pigment, it is easy to hinder the volatilization of tensio-active agent and, because the incomplete tensio-active agent of volatilization makes dispersant coloring influence the normal hair color of pigment, so must select the tensio-active agent that is easy to volatilize. Therefore, the second invention has a narrower selection of surfactants than the first invention.

(4) The above-mentioned fluorine-containing resin coating composition for screen coating according to the second invention of the present application is characterized in that the fluorine-containing resin particles are PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer).

(5) The above-mentioned fluorine-containing resin coating composition for screen coating in embodiment (4) of the second invention of the present application is characterized in that the fluorine-containing resin particles are spherical PFA particles with an average particle diameter of 10-30 μm and, A mixture of PFA particles with a molecular weight lower than PFA and an average particle size of 10 μm or less.

The third invention of the present application is a method for producing a fluorine-containing resin backed board, which is characterized in that a fluorine-containing resin coating composition that does not contain pigments is dispersed in a dispersant mainly composed of a surfactant , is applied to almost the entire surface of a flat substrate by screen coating, dried and sintered. Furthermore, an embodiment of the third invention of the present application includes at least the following.

(6) The method for manufacturing a fluorine-containing resin clad board according to the third invention of the present application, wherein the plate-like substrate is a fluorine-containing resin clad board clad with a fluorine-containing resin containing a pigment.

(7) The method for manufacturing a fluorine-containing resin backed sheet according to the third invention of the present application is characterized in that the plate-shaped substrate is a metal plate with a roughened surface.

(8) The method of manufacturing a fluorine-containing resin coated sheet in the above-mentioned embodiment (7) of the third invention of the present application, characterized in that the surface roughening is performed by anodic electrolytic oxidation.

(9) The method of manufacturing a fluorine-containing resin coated sheet in the above-mentioned embodiment (7) of the third invention of the present application, wherein the metal sheet is an alloy sheet mainly composed of aluminum, or stainless steel is bonded thereon. Composite panels.

(10) The above-mentioned method for manufacturing a fluorine-containing resin coated board according to the third invention of the present application is characterized in that the fluorine-containing resin particles have a set film thickness t or less of the fluorine-containing resin coating, and the opening of the screen printing yarn The average particle diameter below the pore length (pitch f-wire diameter a) and the fluorine-containing resin ratio x in the fluorine-containing resin paint containing no pigment should satisfy Mathematical Formula 1.

(mathematical formula 1)

Ratio of fluorine-containing resin in paint x>set film thickness t÷(average yarn thickness d×opening ratio k)

Here, the average yarn thickness d=2a×(a/f) ² +a{1-(a/f)} ³

Opening ratio k＝{(fa)/f} ²

The fourth invention of the present application is a method for manufacturing a fluorine-containing resin clad board, which is characterized in that fluorine-containing resin particles and pigments are dispersed in a dispersant mainly composed of a surfactant, the surfactant is essentially only It is composed of alkyl and oxyalkylene, does not contain aromatic rings, carbon-carbon heavy bonds, and is a non-ionic surfactant with a chemical structure composed of carbon, hydrogen, and oxygen atoms. It is a chlorine-containing resin coating composition. The mesh coating method is applied to almost the entire surface of a flat substrate, dried and fired.

(11) The method for producing a fluorine-containing resin clad sheet according to the fourth invention of the present application, wherein the plate-like substrate is a fluorine-containing resin clad sheet coated with a fluorine-containing resin not containing a pigment.

(12) The method for producing a fluorine-containing resin backed sheet according to the fourth invention of the present application, wherein the plate-like substrate is a metal plate with a roughened surface.

(13) The method for producing a fluorine-containing resin coated sheet in the above-mentioned embodiment (12) of the fourth invention of the present application, characterized in that the surface roughening is performed by anodic electrolytic oxidation.

(14) The method of manufacturing a fluorine-containing resin coated sheet in the above-mentioned embodiment (12) of the fourth invention of the present application, wherein the metal sheet is an alloy sheet mainly composed of aluminum, or a stainless steel sheet is bonded thereon. Composite panels.

(15) The above-mentioned method for manufacturing a fluorine-containing resin coated plate according to the fourth invention of the present application is characterized in that the fluorine-containing resin particles have a set film thickness t or less of the fluorine-containing resin coating, and the thickness of the screen printing yarn is The average particle size below the opening length (pitch f-wire diameter a) and the non-volatile component ratio x of the fluorine-containing resin and pigment in the fluorine-containing resin paint should satisfy Mathematical Formula 2.

(mathematical formula 2)

Ratio x of non-volatile components such as fluorine-containing resins and pigments in paint > set film thickness t÷(average yarn thickness d×opening ratio k)

Here the average yarn thickness d=2a×(a/f) ² +a×{1-a/f) ² }

Opening ratio k＝{(fa)/f} ²

The fifth invention of the present application is a method for producing a fluorine-containing resin to be processed, which is characterized in that the fluorine-containing resin particles are dispersed in a dispersant mainly composed of a surfactant, and a fluorine-containing resin paint that does not contain a pigment is combined. The fluorine-containing resin cladding plate (the fluorine-containing resin cladding plate obtained by the third invention of the present application) obtained by applying the screen coating method to approximately the entire surface of the flat substrate, drying and sintering, in this Stress is applied to the plate to make any shape.

The sixth invention of the present application is a method for producing a fluorine-containing resin complex product, which is characterized in that fluorine-containing resin particles and pigment particles are dispersed in a dispersant mainly composed of a surfactant, and the surfactant is substantially only It is composed of alkyl and oxyalkylene, does not contain aromatic rings, carbon-carbon double bonds, and is a non-ionic surfactant with a chemical structure composed of carbon, hydrogen, and oxygen atoms. It is a fluorine-containing resin coating composition. The fluorine-containing resin coated plate obtained by applying the screen coating method to approximately the entire surface of the flat substrate, drying and sintering (the fluorine-containing resin coated plate obtained by the method of the fourth invention of the present application), on the plate Apply stress to make any shape.

The seventh invention of the present application is a method for producing a fluorine-containing resin backed board, which is characterized in that a fluorine-containing resin coating composition containing fluorine-containing resin particles dispersed in a dispersant mainly composed of a surfactant and does not contain pigments, Apply the screen coating method to approximately the entire surface of the flat substrate, dry and sinter the obtained fluorine-containing resin to be clad (the fluorine-containing resin to be clad with the third invention of the present application), and then use the following Fluorine-containing resin melting point 50°C - 50°C higher than the temperature of the fluorine-containing resin melting point, pressurize the fluorine-containing resin surface while heating. Furthermore, an embodiment of the seventh invention of the present application includes at least the following.

(16) The above-mentioned method for manufacturing a fluorine-containing resin backed plate according to the seventh invention of the present application is characterized in that heating is performed within a temperature range of 20° C. lower than the melting point of the fluorine-containing resin to 20° C. higher than the melting point of the fluorine-containing resin. While applying pressure to the fluororesin surface.

The eighth invention of the present application is a method for manufacturing a fluorine-containing resin clad board, which is characterized in that fluorine-containing resin particles and pigment particles are dispersed in a dispersant mainly composed of a surfactant, and the surfactant is substantially Composed only of alkyl groups and alkylene oxides, non-ionic surfactants with a chemical structure consisting of carbon, hydrogen, oxygen, and atoms without aromatic rings or carbon-carbon double bonds, fluorine-containing resin coating combinations The material is applied to approximately the entire surface of the planar substrate by screen coating, and the fluorine-containing resin obtained by drying and sintering (the fluorine-containing resin obtained by the fourth invention of the present application) is coated, and then used Pressurize the surface of the fluororesin while heating at a temperature of 50°C lower than the melting point of the fluororesin to 50°C higher than the melting point of the fluororesin. Furthermore, an embodiment of the eighth invention of the present application includes at least the following.

(17) The above-mentioned method for producing a fluorine-containing resin backed plate according to the eighth invention of the present application is characterized in that the fluorine-containing resin is heated at a temperature of 20° C. lower than the melting point of the fluorine-containing resin to 20° C. higher than the melting point of the fluorine-containing resin. The fluororesin surface is pressurized.

The ninth invention of the present application is a method for producing a fluorine-containing resin to-be-processed product, which is characterized in that the fluorine-containing resin particles are dispersed in a dispersant mainly composed of a surfactant and does not contain a pigment. The composition is applied to approximately the entire surface of a planar substrate by screen coating method, and the fluorine-containing resin obtained by drying and sintering is covered with a fluorine-containing resin. While heating at a melting point of 50°C, pressurize the surface of the fluorine-containing resin to obtain a fluorine-containing resin cladding board (the fluorine-containing resin cladding board obtained by the seventh invention of the present application), and then apply stress to the board. into any shape.

The tenth invention of the present application is a method for producing a fluorine-containing resin complex product, which is characterized in that fluorine-containing resin particles and pigment particles are dispersed in a dispersant mainly composed of a surfactant, and the surfactant is substantially The surface is only composed of alkyl and oxyalkylene, does not contain aromatic rings, carbon-carbon heavy bonds, and is a non-ionic surfactant with a chemical structure composed of carbon, hydrogen, and oxygen atoms. Fluorine-containing resin coating combination fluorine-containing resin, which is coated on the entire surface of the flat substrate by the screen coating method, dried and sintered to obtain a fluorine-containing resin, and then coated with a fluorine-containing resin that is 50°C lower than the melting point of the fluorine-containing resin - 50°C higher than the melting point of the fluorine-containing resin. While heating, the fluorine-containing resin surface is pressurized to obtain a fluorine-containing resin plate (a fluorine-containing resin to be clad plate obtained by the eighth invention of the present application), and then stress is applied to the plate to make any shape.

In screen printing, since the paint is placed on the mesh-shaped yarn (screen hole), and scraped with a scraper, only the paint that passes through the mesh forms a coating film, so it is completely coated with the screen coating method. When applying fluorine-containing resin or fluorine-containing resin containing pigment, the following conditions must be met, that is, 1) from the nature of the coating, the main components of the coating (fluorine-containing resin, dispersant, etc., or fluorine-containing resin, pigment, dispersion agent, etc.) should be able to pass through the mesh of the yarn; after passing through, it should be able to be flattened quickly without leaving traces of the mesh; it should have viscosity that does not damage the set film thickness and coating shape; for scraping with a scraper , The paint and paint composition should not change.

In addition, 2) during sintering, even if the sintering is carried out within the temperature control range commonly used in industry, no coloring occurs after sintering, and the physical properties of the fluorine-containing resin and the coating film do not change.

The condition of 1) is properly determined according to the size of the fluorine-containing resin particles, the shape of the yarn, the viscosity of the paint, etc., and the condition of 2) is important in the selection of the surfactant.

As the fluorine-containing resin used in the present application, various fluorine-containing resins can be used, such as PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer), FEP ( Tetrafluoroethylene/hexafluoropropylene copolymer), ETFE (tetrafluoroethylene/ethylene copolymer), CTFE (polychlorotrifluoroethylene), PVdF (polyvinylidene fluoride) and copolymers of these, either alone or as a mixture use.

Among them, from the point of view that it is difficult to cause coating defects even if the pigment component is increased, it is best to use heat-melting fluorine-containing resins such as PFA, FEP, ETFE, CTFE, and PVdF. Use PFA, FEP.

Such fluorine-containing resins are available in the form of powder or dispersion. From the viewpoint of easy film formation, it is preferable to use spherical or amorphous particles with an average particle diameter of 5 μm or more. Resins containing 10-30 μm particles are suitable for forming thick films and coatings with appropriate viscosity for screen coating. advantageous. In addition, appropriate inclusion of small fluorine-containing resin particles with an average particle diameter of 10 μm or less is useful for smoothing the surface of the coating film after sintering. In particular, when a variety of pigments are mixed, the effect is remarkable, and the effect is greater when small particles with low molecular weight (low melt viscosity) are used.

In order for the particles to pass through the gauze used for screen printing, the particle size should be smaller than the opening length of the yarn. The opening length is defined by subtracting the wire diameter a from the distance f between the meshes of the yarn. The f of the general yarn is usually 50-600 μm, and the a is 25-160 μm, so the opening length is 25-500 μm. When it is necessary to use large particles, yarns with long openings can be used, and the opening length corresponding to the particle diameter can be freely set, but in the present invention, the opening length in a particularly preferred embodiment is 50 μm or more. , more preferably 100 μm or more.

Any pigment can be used as the pigment used in the present invention. Examples include white pigments such as titanium oxide and zinc white, black pigments such as carbon black and acetylene black, color pigments such as ultramarine blue and Bengala iron oxide, boron nitride, mica, pigment-coated mica, fluorinated Flake pigments such as carbon, etc.

In addition to the above inorganic pigments, organic pigments or dyes, heat-resistant polymer materials may be used as necessary. For example, phthalocyanine pigments, indigo dyes, polyimides, polyimides, polysulfone ethers, polyphenylene sulfides, epoxy resins, etc. They are used in the form of solutions and powder dispersions.

The compounding amount of these pigment components is adjusted so that the color of the fluorine-containing resin coated after sintering can show an arbitrary color. The compounding amount is different according to the type of pigment and the displayed color, and can be set arbitrarily according to the required purpose, but generally accounts for 0.001wt%-10wt% of the non-volatile components of the paint.

The thickness of the coating film is calculated as the coating thickness of the paint x the ratio of fluorine-containing resin in the paint (in the third, fifth, seventh, and ninth inventions of this application) or the thickness of the paint coating x the fluorine-containing resin and pigment in the paint, etc. The ratio in the non-volatile components (in the 4th, 6th, 8th, and 10th inventions of the present application) is determined. In fact, when the gauze is fixed and the ratio of the fluorine-containing resin is changed for experiments, the ratio of the fluorine-containing resin is related to the thickness of the coating film, so the coating thickness of the coating can be roughly determined according to the "average yarn thickness d" . Since the usual meshes are woven with spun yarns (see Figure 1 and Figure 2), the thickness of the yarn is about twice the diameter a of the wire. But in fact, only the yarn thickness of the overlapping part of the yarn is twice the wire diameter a, and the yarn thickness of the non-overlapping part is the wire diameter a. Especially for rovings with a small mesh number, the yarn thickness is substantially closer to the wire diameter a.

Therefore, in consideration of the area ratio of the overlapped parts of the braided lines, in the third, fifth, seventh, and ninth inventions of the present application, if the "average yarn thickness d" is defined according to (2) of Mathematical Formula 3, or in the present application In the fourth, sixth, eighth, and tenth inventions, if defined according to (2) of Mathematical Formula 4, in order to obtain the set film thickness t, Mathematical Formula 3 or Mathematical Formula 4 can be used to obtain it.

(mathematical formula 3)

Ratio of fluorine-containing resin in paint x>set film thickness t÷(average yarn thickness d×opening ratio k)

…(1)

Here the average yarn thickness d=2a×(a/f) ² +a×{1-(a/f) ² }…(2)

Opening ratio k＝{(fa)/f} ² …(3)

(mathematical formula 4)

Ratio of non-volatile components such as fluorine-containing resin and pigment in the paint X>

Set film thickness t÷(average yarn thickness d×opening ratio k) …(1)

Here, the average yarn thickness d=2a×(a/f) ² +a×{1-(a/f) ² }…(2)

Opening ratio k＝{(fa)/f} ² …(3)

For example, in the third, fifth, seventh, and ninth inventions of the present application, if one wants to obtain a coating film with a film thickness of more than 20 μm, use a yarn with 120 meshes (212 μm in pitch), 80 μm in wire diameter, and 39% of the opening ratio. Calculated according to (1) in Mathematical Formula 3, the required ratio of fluorine-containing resin is more than 56%, but the experimental results show that when the ratio of fluorine-containing resin is 50%, it cannot meet the requirement of a film thickness of 20 μm, and it can be coated with 60%. into about 20 μm. Therefore, it is useful to use Mathematical Expression 3 in order to obtain a predetermined film thickness.

The viscosity of the coating has a great influence on the thickness and leveling of the coating film during screen printing. The paint viscosity of the fluorine-containing resin dispersion in the present invention can be evaluated using a screw viscometer (PCI-TL manufactured by Marncom Corporation).

When the viscosity of the paint is high and the fluidity is too low, it is difficult to apply the paint evenly. Bubbles and the like are generated during application. It is also difficult to determine the proper viscosity of the paint according to the properties of the particles and dispersants, but the range in which screen coating can be carried out smoothly is that when the scraping speed is 6/second, its apparent viscosity = 50- 5000P, preferably 50-1000P.

In the above 2), it is important to select a surfactant corresponding to the fluororesin. The ratio x of the fluorine-containing resin in the paint (in the third, fifth, seventh, and ninth inventions of the present application), or the ratio x of the non-volatile components of the fluorine-containing resin and pigments in the coating (the fourth, fifth, and ninth inventions of the present application) 6, 8, and 10 inventions) can be calculated by mathematical formula 3 or mathematical formula 4, although it is also related to the set film thickness t, for common yarns, it is preferably 25-80%, more preferably 50% -80%. In order to form a stable dispersed paint with the fluorine-containing resin in the above ratio, a considerable amount of surfactant is required, and its selection has a great influence on the formation of the paint film.

For example, when PFA is used as a fluorine-containing resin, the drying and sintering conditions of the coating film should be set after considering the melting temperature (300-310°C) and obvious thermal decomposition temperature (above 400°C) of PFA. When considering the actual industrial production, it is hoped that the heating and sintering process can be completed in the shortest possible time.

The surfactant should be decomposed and volatilized almost completely without remaining in the coating film under its setting conditions. From this point of view, it can be selected arbitrarily, but from the point of view that it is particularly easy to decompose and volatilize, and it is difficult to leave a surplus, it is best to choose non-ionic Sexual surfactant.

As specific examples of nonionic surfactants, ethylene oxide/propylene oxide copolymers (decomposition temperature 160-180°C) and polyoxyethylene alkyl ethers (decomposition temperature 140-180°C) can be used. Polyoxyethylene alkylphenyl ether (decomposition temperature 170-260° C.) and the like are representative, and their partially fluorinated nonionic surfactants. However, surfactants containing aromatic rings such as benzene rings in the molecules of polyoxyethylene alkylphenyl ethers, due to their high decomposition temperature, often remain carbides even after thermal decomposition, which will cause the coloring of the coating film. When the fluorine-containing resin of the pigment, especially the white pigment, causes the problem of coloring, it is best not to use it or to control its compounding amount to a minimum. It is better to choose other more volatile surfactants as the main component. The same applies to surfactants containing multiple bonds. In addition, since heteroatoms containing nitrogen, sulfur, phosphorus, etc. are also likely to cause coloring, use should be avoided as much as possible. Other dispersants such as water, general organic solvents, and liquid polymers can also be added to the paint. It is preferable that these dispersants can completely evaporate and disperse under the set drying and sintering conditions, and it is preferable to use dispersants with relatively low boiling point and decomposition point.

In the third and fourth inventions of the present application, any fluorine-containing resin to be covered as the substrate can be used. In particular, its manufacturing method may or may not be according to the method of the present invention, and there is no limitation to this. Preferably, the laminated structure shown in (6) of the embodiment of the third invention of the present application and (11) of the embodiment of the fourth invention of the present application can achieve the following objects.

The laminated structure of embodiment (6) of the third invention of the present application:

The fluorine-containing resin layer containing pigment is easy to cause the occurrence of pores and the decrease of non-adhesiveness, so the outermost layer is set as a fluorine-containing resin layer without pigment to reduce pores and improve non-adhesiveness.

The laminated structure of the embodiment (11) of the fourth invention of the present application:

Since the adhesive force between the fluorine-containing resin containing the pigment and the metal substrate is lowered, an adhesive component is often added. Although PAI (polyimide), PES (polyethersulfone), etc. are used as binding components, the binding force of these substances tends to decrease in boiling water, so they cannot be used for boiling and other purposes. In order to obtain the adhesive force suitable for these purposes, and to be able to be colored in appearance, as the base material, a metal plate whose surface is finely roughened by corrosion or other methods is used, and the layer that is in direct contact with the base material is used. A fluorine-containing resin containing a pigment is covered with a layer of a fluorine-containing resin containing a pigment.

The screen-coated substrates in the embodiments (7), (8), and (9) of the third invention of the present application and the embodiments (12), (13), and (14) of the fourth invention have roughened surfaces. flat substrate. The surface roughening method mainly uses chemical or electrochemical corrosion methods, which can be carried out alone or in combination. In addition, physical roughening methods such as sand blasting and grain blasting may be used alone or in combination.

No matter what kind of roughening method is used, since the coating strength of the coating film is increased by providing fine unevenness on the surface of the substrate, a positive effect can be produced. The degree of roughening (the degree of unevenness) varies depending on the type of coating resin, the composition of the pigment, and the required bonding strength. The degree RZ is preferably in the range of 4-50.

Examples of the type of the substrate include Al and an alloy plate mainly composed of Al. Examples of the Al alloy plate include Mg—Mn-based alloy plates. In addition, magnetic metal plates such as iron and stainless steel may be bonded to these Al plates and Al alloy plates to form a composite plate (see JP-A-5-116244). The above examples are also applicable to other metal plates in general.

With the embodiment (7), (8), (9) of the third invention of the present application and the embodiment (12), (13), (14) of the fourth invention, the fluorine-containing resin plate manufactured is due to the Fluorine-containing resin with or without pigment is directly coated on the roughened substrate on the metal plate, so sufficient coating strength can be achieved. However, due to the difference in various conditions such as the type, molecular weight, melt viscosity, solid content, drying conditions, sintering conditions, or pigment type (size, shape, material) and addition amount of the fluorine-containing resin, the content of the fluorine-containing resin after drying and sintering is different. The coated surface of fluororesin is not smooth, and often has a slightly rough feeling. The same situation also occurs when using a clad substrate coated with fluorine-containing resin. Pressurize the fluorine-containing resin while heating in the range of low temperature 50°C lower than the melting point of the resin - high temperature 50°C higher than the melting point, preferably in the temperature range of low temperature 20°C lower than the melting point - high temperature 20°C higher than the melting point surface to increase the smoothness of the surface (the eighth and ninth inventions of the present application).

Specifically, when PFA is used as the fluorine-containing resin, it can be completed after an arbitrary period of time by applying pressure in a heated environment near the melting point of PFA (302-310° C.) (about 300° C.).

The apparatus for pressing can be a batch type in which several or tens of sheets are laminated and heated and pressed at one time, or a continuous heat press method using a hot roller. Any structure can be used as long as it can improve the smoothness of the surface, pressurize, heat, or have a structure that can be processed for a certain period of time. Furthermore, the applied pressure, as long as the fluorine-containing resin can be plastically deformed at high temperature or within the pressure range of smoothing effect through melt flow, there are no special restrictions on this, preferably 400-600kgf/cm ² .

The fluorine-containing resin doubler plate produced in this way is subjected to stress by press molding, and is made into an arbitrary shape for practical use. Such as inner pots and hot plates for rice cookers, inner pots for electric water boilers.

A brief description of the graph

Fig. 1 is a schematic front view illustrating the mesh structure of a general wire mesh.

Fig. 2 is a schematic side view of Fig. 1 .

The best solution for implementing the present invention

Experiment 1

As the fluorine-containing resin, PFA (MP102: average particle size 20 μm, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) was used, and the resin ratio for production was 70%, and various surfactants shown in Table 1 were mixed with the paint, and the screen was coated with It was printed on a substrate (aluminum plate with a diameter of 10 cm and whose surface was coated with PTFE). A gauze of 120 mesh and a wire diameter of 80 μm was used. After standing at room temperature for 30 minutes, it took 17 minutes to raise the temperature from 50°C to 250°C, dry and sinter at 250°C for 12 minutes, and dry and sinter at 380°C for 24 minutes to obtain a coating film. The film thickness was measured with an eddy current type film thickness gauge, and evaluated by a grid test (100/100, tape peeled 20 times with a pitch of 1 mm). The coloring of the coating film was measured with a colorimeter (manufactured by Minolta), and the color difference from the substrate surface was evaluated.

Table 1 Surfactant №Compound paint Paint viscosity POise Film thickness Adhesion Chromatic coloring um 100/100 Overview chemical structure Product number (manufacturer) Ethylene Oxide/Propylene Oxide Copolymer PL910 (Sanyo Chemical) A resin 70% + surfactant 30% 380B resin 70% + surfactant 26% 300 + butyl cellosolve 4% 27 OK ○29 OK ○ ◎◎ Boolean 102 (Japanese oil) C resin 70% + surfactant 30% 530D resin 70% + surfactant 26% 420 + butyl cellosolve 4% 29 OK ○32 OK ○ ◎◎ Polyoxyethylene octylphenyl ether Simbol 45 (Sanyo Chemical) E resin 70% + surfactant 30% 1020F resin 70% + surfactant 26% 560 + water 4% 23 OK △24 OK △ ○○ Fatty acid alcohol amides Bulfan EX24 (Sanyo Chemical) G resin 70% + surfactant 30% 790H resin 70% + surfactant 26% 620 + butyl cellosolve 4% 26 OK △24 OK △ ○○

^* Apparent viscosity measured with a screw viscometer (scraping speed 6/sec, room temperature)

As shown in Table 1, when using surfactants containing benzene rings (E.F) and surfactants containing nitrogen atoms (G.H), the coating film can be colored. On the contrary, when using surfactants containing no aromatic rings, heavy bonds, hetero Atomic surfactants (A-D) cannot be colored. However, in all of them, a fluorine-containing resin coating film with good adhesion and uniform film thickness can be obtained.

Experiment 2

The same fluorine-containing resin PFA (MP102: average particle size 20 μm, manufactured by Mitsui Dupont Fluorochemical Co., Ltd.) was used as in Experiment 1, and 100% of surfactant Simbol No. 45 and Xinbol PE61 (both Sanyo Chemicals Co., Ltd.) made coatings with a resin ratio of 50, 60, and 70%, and screen printed them on a substrate (a 2 mm thick aluminum plate with a diameter of 10 cm and coated with PTFE). Two types of gauzes, 80 mesh and 120 mesh described in Table 2, were used. After 30 min at room temperature, pass through at 100 °C for 5 min. The coating film was obtained after drying and sintering under the heating conditions of 250°C for 5 minutes and 390°C for 20 minutes. The film thickness was measured with an eddy current type film thickness meter, and the results of the measurement are shown in Table 3.

Table 2

Use gauze specifications abbreviation head Wire diameter a Spacing f Average yarn thickness d Opening ratio k roots/inch μm μm μm % 80M 80 50 318 51.2 71 120M 120 80 212 91.2 39

table 3 With paint paint viscosity head Measured film thickness wxya №Surfactant Resin RatioX poise μm μm ①Simple #45②③④⑤⑥ 50% 750 80M120M 8.87.8 18.217.2 60% 780 80M120M 1121 21.821.3 70% 1020 80M120M 2324 25.424.9 ⑦New Ball P161⑧⑨(10) 60% 440 80M120M 1021 21.821.3 70% 780 80M120M 1923 25.424.9

^* Apparent viscosity measured with a helical viscometer (scraping speed 6/sec, room temperature)

It can be seen from Table 2 and Table 3 that the condition represented by (1) in Mathematical Formula 3 can be satisfied.

Experiment 3

An aluminum alloy plate (ASB material manufactured by Kobe Steel Corporation) having a plate thickness of 2.0 mm was used as the base material. The aluminum alloy plate is used as an anode, and electrochemical corrosion treatment is carried out in an ammonium chloride aqueous solution with an electric quantity of 25 coulombs/cm ² to roughen the surface. Next, according to the compounding shown in Table 4, a fluorine-containing resin paint was prepared.

Table 4 PFA Mica 10-60um carbon black TiO ₂ Surfactant Average particle size 20μm Average particle size 7μm *1 *2 iiiiii 168167156 no no no 778.8 00.20 00.80 252525 505050

(Note) ^*1 Ethylene oxide/propylene oxide copolymer system

^*2 Polyoxyethylene alkyl ether series

The above paint screen was coated on a roughened Al plate (90mmφ). The screen used was 120 mesh, 80 μm in wire diameter, and 132 μm in opening length for i and ii, and 80 mesh, 120 μm in wire diameter, and 198 μm in opening length for iii. After drying and sintering at 100°C for 5 minutes; 250°C for 10 minutes; 390°C for 20 minutes, the obtained coating films are all about 40 μm in thickness and have sufficient adhesion.

For ii, some roughness was found on the surface. For samples i-iii after sintering, smoothing treatment was carried out for three hours using a hot press at a furnace setting temperature of 430°C and a pressure of 550kg/cm ² . As a result, the roughness on the surface disappeared, and the surface became completely flat.

table 5

Evaluate the results with a roughness meter

(Re: expressed by the average thickness of the center line) i i iii After sintering 4 12 5 After hot pressing 1 1.7 1

Experiment 4

A fluorine-containing resin of PFA (MP102: average particle size 20 μm, manufactured by Mitsui DuPont Fluorochemical Co., Ltd., 300 g) and a surfactant of ethylene oxide/propylene oxide copolymer (PL-910: manufactured by Sanyo Chemical Industry, 200 g) were mixed. , made of fluororesin coatings. The substrate is an aluminum alloy plate (MG-110 material from Sumitomo Light Metal Co., Ltd.) with a thickness of 1.2mm, and the surface is roughened by electrochemical etching, and then coated with a fluorine-containing resin containing pigment and mica. The above-mentioned fluorine-containing resin mesh was coated on this base material using a yarn of 150 mesh and a wire diameter of 60 μm. Immediately after coating, dry at 40°C for 4 minutes, raise from 40°C to 380°C in 6 minutes, and sinter at 380°C for 7 minutes to obtain a coating film. The film thickness was measured with an eddy current film thickness meter, and the film thickness of the coating coated with the screen was 17-24 μm. In addition, when the coloring of the coating film was measured with a colorimeter (manufactured by Minolta), and the color difference from the surface of the substrate was evaluated, ΔE=0.5, almost no discoloration was observed, which was good. In addition, the sintered plate was heated and pressed with a hot press at a furnace set temperature of 430°C, a pressure of 550kg/cm ² , and an extrusion time of 1 hour. It was confirmed that the Ra (center line roughness) Smooth from 2μm to 0.8μm. On the other hand, the sintered plate was processed into the shape of the inner sleeve of the moisturizing rice cooker with a press, and the actual cooking test was carried out 180 times. The result was that the coating film was not found to be bubbling or broken due to corrosion, and it was very durable.

As mentioned above, using the fluorine-containing resin coating composition of the present invention, the manufacturing method of the fluorine-containing resin to be coated, and the manufacturing method of the fluorine-containing resin to be processed, the coating of the fluorine-containing resin can be realized by the screen coating technology. Fully covered, it can not only be applied to the inner pot of the previous rice cooker, but also can be applied to large-area (such as 1m) fluorine-containing resin processing and hydrophobic processing on an industrial production scale. Especially for the manufacture of inner pots of rice cookers, baking pots, and inner sleeves of heat preservation pots, it is easy to make fluorine-containing resin coatings with a thickness of more than 20 μm, which can achieve thicker films and overcome the loss of coatings. The non-uniform film thickness can also be easily made into multi-colored tones and arbitrary patterns, so it is extremely useful in industry.

Claims (11)

1. silk screen is coated with application fluorine resin paints composition, it is characterized in that the fluorine resin particle is dispersed in the dispersion agent based on nonionic surfactant, and does not contain pigment.

2. be coated with application fluorine resin paints composition by the described silk screen of claim 1, it is characterized in that tensio-active agent in fact only is to be made of alkyl and oxyalkylene, do not contain the Multiple Bonds between aromatic nucleus, carbon-carbon, just the nonionic surfactant of the chemical structure of forming by carbon, hydrogen, Sauerstoffatom.

3. silk screen is coated with application fluorine resin paints composition, it is characterized in that fluorine resin particle and pigment particles are dispersed in the dispersion agent based on tensio-active agent, this tensio-active agent in fact only is to be made of alkyl and oxyalkylene, do not contain the Multiple Bonds between aromatic nucleus, carbon-carbon, just the nonionic surfactant of the chemical structure of forming by carbon, hydrogen, Sauerstoffatom.

4. fluorine resin is by the manufacture method of compound plate, it is characterized in that in dispersion agent, to have disperseed the fluorine resin particle based on nonionic surfactant, and the fluorine resin paints composition that does not contain pigment, be coated onto on approximately all faces of flat-shaped substrate drying and sintering and making by the silk screen coating process.

5. fluorine resin is by the manufacture method of compound plate, it is characterized in that in dispersion agent, to have disperseed fluorine resin particle and pigment particles based on tensio-active agent, this tensio-active agent in fact only is to be made of alkyl and oxyalkylene, do not contain the Multiple Bonds between aromatic nucleus, carbon-carbon, the nonionic surfactant of the chemical structure of forming by carbon, hydrogen, Sauerstoffatom just, the fluorine resin paints composition, be coated onto on approximately all faces of flat-shaped substrate drying and sintering and making by the silk screen coating process.

6. fluorine resin is by the manufacture method of multiple machining object, it is characterized in that in dispersion agent, to have disperseed the fluorine resin particle based on nonionic surfactant, and the fluorine resin paints composition that does not contain pigment, be coated onto by the silk screen coating process on approximately all faces of flat-shaped substrate, drying and sintering and the fluorine resin that obtains are by compound plate, and stress is made shape arbitrarily in addition onboard.

7. fluorine resin is by the manufacture method of multiple machining object, it is characterized in that will disperse fluorine resin particle and pigment particles and this tensio-active agent in the dispersion agent based on tensio-active agent in fact only is to be made of alkyl and oxyalkylene, do not contain aromatic nucleus, Multiple Bonds between carbon-carbon, just by carbon, hydrogen, the nonionic surfactant of the chemical structure that Sauerstoffatom is formed, the fluorine resin paints composition, be coated onto by the silk screen coating process on approximately all faces of flat-shaped substrate, drying and sintering and the fluorine resin that obtains are by compound plate, and stress is made shape arbitrarily in addition onboard.

8. fluorine resin is by the manufacture method of compound plate, it is characterized in that in dispersion agent, to have disperseed the fluorine resin particle based on nonionic surfactant, and the fluorine resin paints composition that does not contain pigment, be coated onto by the silk screen coating process on approximately all faces of flat-shaped substrate, drying and sintering and the fluorine resin that obtains are by compound plate, with being lower than 50 ℃ of fluorine resin fusing points-be higher than the temperature of 50 ℃ of fluorine resin fusing points, the fluorine resin face is pressurizeed again while heat.

9. fluorine resin is by the manufacture method of compound plate, it is characterized in that in dispersion agent, to have disperseed fluorine resin particle and pigment particles based on tensio-active agent, and this tensio-active agent in fact only is to be made of alkyl and oxyalkylene, do not contain aromatic nucleus, Multiple Bonds between carbon-carbon, just by carbon, hydrogen, the nonionic surfactant of the chemical structure that Sauerstoffatom is formed, the polyfurolresin coating composition, be coated onto by the silk screen coating process on approximately all faces of flat-shaped substrate, drying and sintering and the fluorine resin that obtains are by compound plate, with being lower than 50 ℃ of fluorine resin fusing points-the be higher than temperature of 50 ℃ of fluorine resin fusing points, heating on one side, on one side the fluorine resin face is pressurizeed.

10. fluorine resin is by the manufacture method of multiple machining object, it is characterized in that in dispersion agent, to have disperseed the fluorine resin particle based on nonionic surfactant, and the fluorine resin paints composition that does not contain pigment, be coated onto by the silk screen coating process on approximately all faces of flat-shaped substrate, drying and sintering and the fluorine resin that obtains are by compound plate, to this plate with being lower than 50 ℃ of fluorine resin fusing points-the be higher than temperature of 50 ℃ of fluorine resin fusing points, heating on one side, on one side to the pressurization of fluorine resin face and make fluorine resin by compound plate, again to this plate in addition stress make shape arbitrarily.

11. fluorine resin is by the manufacture method of compound plate machining object, it is characterized in that in dispersion agent, to have disperseed fluorine resin particle and pigment particles based on tensio-active agent, and this tensio-active agent in fact only is to be made of alkyl and oxyalkylene, do not contain aromatic nucleus, Multiple Bonds between carbon-carbon, just by carbon, hydrogen, the nonionic surfactant of the chemical structure that Sauerstoffatom is formed, the fluorine resin paints composition, be coated onto by the silk screen coating process on approximately all faces of flat-shaped substrate, drying and sintering and the fluorine resin that obtains are by compound plate, again with being lower than 50 ℃ of fluorine resin fusing points-the be higher than temperature of 50 ℃ of fluorine resin fusing points, heating on one side, on one side pressurization obtains fluorine resin by compound plate to the fluorine resin face, to this plate in addition stress make shape arbitrarily.

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