JP2003053261A - Method for producing fluororesin coating film, fluororesin coating film and processed article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a fluororesin lining in which a thick film can be formed without necessity to incorporate a heat stabilizer in a fluororesin lining layer constituted of a fluororesin and without causing problems such as foaming, degradation and coloring, and exudation of metal ions and the like can be prevented in use. SOLUTION: In the method for producing a fluororesin coating film comprising the steps of forming a primer layer, and forming the fluororesin lining layer on the primer layer, the primer layer contains a fluororesin for the primer layer (a), a heat-resistant binder and a heat stabilizer, and the fluororesin lining layer contains a fluororesin for the lining layer (b).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a lining which contains a fluororesin in high purity and which can prevent leaching of stabilizers, metal ions and the like and can prevent thermal deterioration of the fluororesin. And linings and processed articles produced by the above method.

[0002]

2. Description of the Related Art Chemical / medical instruments, piping materials for semiconductor manufacturing equipment, etc., are normally brought into contact with chemicals during use, so that they are provided with resistance to chemicals and corrosion resistance. Is desirable. Conventionally, glass lining has been mainly used for the purpose of imparting corrosion resistance,
Since it is difficult to handle, it has been requested to change to another corrosion resistant material.

As a corrosion-resistant material to replace the glass lining, a fluororesin is used because it has excellent resistance to chemicals such as acids, alkalis, redox agents and various solvents. A fluororesin is applied as a paint such as a powder paint to an object to be coated and then fired to form a film, but in order to impart corrosion resistance, it is usually desired to have a certain film thickness. In coating, the steps of applying and baking are repeated several times.

Fluorine resin is a heat-resistant resin, but when it is heated at a temperature near the melting point or higher for a long time, it decomposes due to thermal deterioration and causes problems such as foaming, brittleness, and brown coloring. Therefore, it is necessary to use a heat stabilizer together with the fluororesin. Further, it has been conventionally difficult to uniformly obtain a relatively thick lining of a fluororesin unless a heat stabilizer is blended.

Among the fluororesins, for example, as a heat stabilizer used for ethylene / tetrafluoroethylene copolymer (ETFE), Japanese Patent Publication No. 48-37980 discloses:
Sulfates of Group IV-A metals such as Sn and Pb are disclosed, and JP-B-48-37981 discloses phosphorus salts of metals selected from alkali metals, Ba and Group IV-A metals. Acid salts are disclosed, and a combination of these phosphates and organic phosphites is disclosed in Japanese Examined Patent Publication No. 48-3.
Japanese Patent Laid-Open No. 49-877.
No. 38 discloses α-alumina, Japanese Patent Publication No. 52-44895 discloses copper and copper compounds, and Japanese Patent Publication No. 59-46529 discloses palladium and palladium compounds. It is disclosed.

[0006] As a heat stabilizer for ETFE, JP-A-55-16057 discloses a combination of a powder of a metal element of Group VIII of the periodic table, an amine-based antioxidant and an organic sulfur-based compound. Japanese Patent Laid-Open No. 55-1
No. 33442 discloses a carbon black powder, an organic sulfur compound and an amine antioxidant, or Zn,
At least one of fine powder of Sn, Co, Ni or Fe
A combination of species is disclosed.

Further, as a heat stabilizer for ETFE, at least one selected from the group consisting of amine antioxidants, organic sulfur compounds and organic tin antioxidants in JP-A-55-9603. Is disclosed. Further, as a heat stabilizer for a fluorovinyl ether / tetrafluoroethylene copolymer (PFA), JP-A-63-12805 is known.
No. 4 discloses an amine-based antioxidant, an organic sulfur-based compound, and the like.

[0008] Conventionally, as a method for applying a fluororesin, a chromium primer is previously applied to an object to be coated and then applied on the object, or a direct coating is applied to the object to be coated without using a primer like ETFE. Either of these methods has been used.

In these coating methods, the fluororesin is decomposed by the subsequent baking to cause adhesion to the article to be coated. Therefore, to produce this adhesion, the amount of heat stabilizer should be limited, but
If the amount is too small, problems such as foaming due to decomposition of the fluororesin occur.

Further, since the heat stabilizer can gradually exude metal ions and the like from the lining, it causes electronic interference in semiconductor manufacturing facilities, and in chemical / medical instruments, etc. There was a problem such as the deterioration of the chemicals. In recent years, the use of fluororesins has increased in the field of semiconductors, but the content of the heat stabilizer has been reduced, and a lining containing the fluororesin in the same high purity as a general molded product has not been obtained.

As a method capable of reducing the content of the heat stabilizer, it is possible to apply by using, for example, the recently developed lot lining method. This method can shorten the coating film application time and is desired to be applied from the viewpoint that thick coating is possible, but the content of the heat stabilizer is
Not as many as before, but still needed to some extent.

In the method of adhering to the object to be coated by decomposing the fluororesin, the decomposition temperature differs depending on the type of the object to be coated, so it is necessary to select the firing temperature at a small level depending on the type of the object to be coated. . If the construction conditions are narrow as described above, there is a problem that the construction often fails.
Therefore, it has been desired to develop a coating film construction method that can be widely and stably applied to various objects to be coated.

There is a method of applying a primer to the object to be coated in advance in order to provide the adhesive property to the object to be coated without depending on the decomposition of the fluororesin. It is preferable not to use a chromium primer that has been conventionally used as a primer because it is necessary to prevent environmental pollution due to chromium in recent years.

As a primer, a PPS-based primer composed of polyphenylene sulfide (PPS) and a polyamide-imide resin is also known. However, since the PPS-based primer is a solid without a solvent that dissolves PPS, it is difficult to apply it uniformly and evenly on the object to be coated, and as a result, voids are formed between the primer and the object to be coated. It is easy to peel off and does not sufficiently solve the problem of adhesion to the object to be coated.

[0015]

In view of the above situation, an object of the present invention is to eliminate the problems such as foaming, embrittlement, and coloring without the need to include a heat stabilizer in the fluororesin lining layer made of fluororesin. It is an object of the present invention to provide a fluororesin lining manufacturing method capable of forming a thick film without causing the generation and preventing the exudation of metal ions and the like during use.

[0016]

The present invention is a method for producing a fluororesin coating film, which comprises forming a primer layer and forming a fluororesin lining layer on the primer layer. The primer layer comprises a fluororesin (a) for a primer layer, a heat resistant binder and a heat stabilizer, and the fluororesin lining layer comprises a fluororesin (b) for a lining layer. It is a method for producing a fluororesin coating film, characterized in that it is contained.

The fluororesin (a) for the primer layer is
It is preferably a tetrafluoroethylene-based copolymer. The heat resistant binder is preferably made of a polymer substance having a melting point, a glass transition point or a softening point of 180 ° C. or higher. The heat stabilizer is a metal, a metal oxide and / or an organometallic compound, and the metal atom contained in the metal, the metal oxide and the organometallic compound has a plurality of atomic numbers of 26 to 56. It is preferably one or more atoms selected from the group consisting of atoms. The heat stabilizer is preferably a reducing compound having at least one selected from the group consisting of nitrogen atom, sulfur atom and phosphorus atom, and is preferably a nonmetal.

The heat stabilizer is preferably a combination of the following (1) and (2). (1) A metal, a metal oxide and / or an organometallic compound, wherein the metal atom contained in the metal, the metal oxide and the organometallic compound is composed of a plurality of atoms having an atomic number of 26 to 56. Those that are one or more atoms selected from the group. (2) A reducing compound having at least one selected from the group consisting of a nitrogen atom, a sulfur atom and a phosphorus atom, and also a nonmetal. The fluororesin lining layer is baked and has a thickness of 100 to 100.
It is preferably 00 μm.

The present invention is also a processed article having an article to be coated and a fluororesin coating film, wherein the fluororesin coating film forms a primer layer on the article to be coated, and the primer layer is formed on the primer layer. A fluororesin lining layer is formed on the primer layer, the primer layer contains a fluororesin (a) for a primer layer and a heat stabilizer, and the fluororesin lining layer is a fluororesin for a lining layer. A processed article containing (b) and not containing a heat stabilizer. Hereinafter, the present invention will be described in detail.

The method for producing a fluororesin coating film of the present invention is for producing a fluororesin coating film by forming a primer layer and forming a fluororesin lining layer on the primer layer. The fluororesin lining layer contains a fluororesin (b) for a lining layer. In forming the fluororesin lining layer, firing is performed for forming a film.

In the present specification, the fluororesin coating film is formed on an object to be coated and contains the primer layer and the fluororesin lining layer. In the present specification, a product having the fluororesin coating film and the article to be coated may be referred to as a processed article.

The primer layer contains a fluororesin (a) for a primer layer, a heat resistant binder and a heat stabilizer. In the present invention, by forming the primer layer, it is possible to obtain adhesion between the fluororesin lining layer and the article to be coated,
It is possible to prevent thermal degradation and decomposition of the fluororesin (b) for the lining layer.

In the present specification, the primer layer is a coating film formed by applying a primer on the object to be coated and drying the primer. Therefore, the above-mentioned fluororesin (a) for primer layer, heat resistant binder and heat stabilizer can be contained in the above primer.
The primer is applied as an undercoat prior to forming the fluororesin lining layer.

The fluororesin (a) for the primer layer is
It is composed of a polymer having a fluorine atom directly bonded to a carbon atom constituting the main chain. The polymer forming the fluororesin (a) for the primer layer is not particularly limited, and examples thereof include those obtained by polymerizing using a fluorine-containing monomer as the monomer component. The above-mentioned fluorine-containing monomer is an ethylenically unsaturated compound having a fluorine atom directly bonded to the carbon atom constituting the main chain.

The above-mentioned fluorine-containing monomer is not particularly limited, and examples thereof include perfluoro-based monomers such as tetrafluoroethylene [TFE] and hexafluoropropylene [HFP]; perfluoro such as perfluoro (propyl vinyl ether). (Alkyl vinyl ether) [PAVE];
Examples thereof include hydrogen-containing fluoroolefins such as vinylidene fluoride [VdF] and vinyl fluoride [VF]; and chlorofluoroolefins such as chlorotrifluoroethylene [CTFE]. These can be used alone or in combination of two or more. . The perfluoro-based monomer is an ethylenically unsaturated compound in which hydrogen atoms are not bonded to carbon atoms constituting the main chain and only fluorine atoms are bonded.

The polymer forming the fluororesin (a) for the primer layer can be obtained by polymerizing the above-mentioned fluoromonomer with another monomer as a monomer component. May be The above-mentioned other monomer is an ethylenically unsaturated compound having no fluorine atom and can be polymerized with the above-mentioned fluorine-containing monomer. The above-mentioned other monomers are not particularly limited, and examples thereof include olefins having no fluorine atom such as ethylene [Et] and propylene [Pr], and these can be used alone or in combination of two or more. .

The polymer forming the fluororesin (a) for the primer layer is not particularly limited, and examples thereof include polytetrafluoroethylene [PTFE], ethylene / tetrafluoroethylene copolymer [ETFE], tetrafluoroethylene / hexa. Fluoropropylene copolymer [FE
P], tetrafluoroethylene-based copolymers such as tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer [PFA]; chlorofluoroolefin-based copolymers such as ethylene / chlorotrifluoroethylene copolymer [ECTFE] ; Polyvinylidene fluoride [PVd
And hydrogen-containing fluoroolefin copolymers such as F].

The tetrafluoroethylene-based copolymer is obtained by polymerizing tetrafluoroethylene as a monomer component. The chlorofluoroolefin-based copolymer is obtained by incorporating chlorofluoroolefin as a monomer component and polymerizing. The hydrogen-containing fluoroolefin-based copolymer is obtained by incorporating hydrogen-containing fluoroolefin as a monomer component and polymerizing.

The polymer forming the fluororesin (a) for the primer layer is preferably the above tetrafluoroethylene copolymer, more preferably ETFE, FEP and PFA. The fluororesin for the primer layer (a) is preferably the same as or similar to the fluororesin for the lining layer (b) described below from the viewpoint of improving interlayer adhesion, although it depends on the application.

The above-mentioned fluororesin (a) for the primer layer was removed.
The polymer is composed of the above-mentioned fluorine-containing monomer and
In addition to the above-mentioned other monomers used as desired,
Use other fluorine-containing monomer for the purpose of controlling crystallinity
It is preferred that the Other fluorine-containing materials mentioned above
The monomer is one that can be added to the above-mentioned fluorine-containing monomer.
There is no particular limitation as long as it is a fluorine-containing vinyl compound having 3 to 8 carbon atoms.
Nyl monomer is easy to use. For example, in case of ETFE.
Hexafluoroisobutylene, CH_Two= CFC _ThreeF
₆H etc. are mentioned. The above other fluorine-containing monomers,
The polymer of the fluororesin (a) for the primer layer
It is preferably 5 mol% or less of the total amount of the monomer components.

As the fluororesin (a) for the primer layer, a fusible fluororesin is preferable because it has excellent film-forming properties and can sufficiently exhibit properties such as corrosion resistance.

The fluororesin (a) for the primer layer has a melt flow rate (MFR) of 0.1 to 100.
It is preferably g / 10 minutes. Within the range of the melt flow rate, the adhesion between the primer layer and the fluororesin lining layer is improved due to the flow characteristics of the fluororesin (a) for primer layer. 0.1
When it is less than g / 10 minutes, the adhesive force between the primer layer and the fluororesin lining layer tends to be lowered, and 1
If it exceeds 00 g / 10 minutes, stress cracks or stress cracks are likely to occur in the primer layer, and corrosion resistance may deteriorate. More preferably, it is 0.5 to 50 g / 10 minutes. The fluororesin for primer layer (a) can have a melt flow rate within the above range by adjusting the copolymerization composition and the molecular weight. In the present specification, the melt flow rate is A
According to STM D3159, temperature 300 ° C, load 5k
It is a value measured as g.

The fluororesin (a) for the primer layer preferably has an average particle size of 0.1 to 30 μm. If it is less than 0.1 μm, the primer layer tends to be cracked, and the film thickness is easily limited,
When it exceeds 30 μm, the primer layer fluororesin (a) lacks uniform dispersibility, and the adhesion to the fluororesin lining layer becomes non-uniform, resulting in poor adhesion.
The thickness is preferably 0.2 to 25 μm, more preferably 0.5 to 20 μm.

The fluororesin (a) for the primer layer is
For example, it can be obtained by polymerization using a conventionally known polymerization method such as emulsion polymerization. The fluororesin powder obtained by polymerization is pulverized, if desired, so as to have an average particle diameter within the above range. The pulverization method is not particularly limited, and for example, a conventionally known method as disclosed in JP-A-63-270740 can be used. For example, the fluororesin powder is rolled into a sheet. Examples include a method of compressing, crushing with a crusher and classification. When the fluororesin for a primer layer (a) is obtained by using emulsion polymerization or suspension polymerization, as long as it satisfies the above-mentioned conditions, it is a dispersion without isolation of the resin component to be obtained. You may use.

The heat-resistant binder is a heat-resistant binder that can function as a binder in the formation of the primer layer. In this specification, heat resistance means the property of being capable of continuous use at a temperature of 150 ° C. or higher. The heat-resistant binder is preferably made of a polymer substance so that the binder sufficiently functions. In the present specification, the polymer substance has a number average molecular weight of 10,000 to 100.
0000. A resin is more preferable as the heat-resistant binder.

The heat resistant binder is preferably one having a melting point, a glass transition point or a softening point of 180 ° C. or higher. If it is less than 180 ° C., the heat resistance may be insufficient at the firing temperature in the fluororesin lining manufacturing method of the present invention or at the use temperature after manufacturing. It is preferably 200 ° C. or higher.

The melting point, glass transition point or softening point of the heat-resistant binder may be below the below-mentioned firing temperature, preferably from the above firing temperature, from the viewpoint that it becomes soft during the above firing and can contribute to film formation. The temperature is 30 ° C. or lower.
The melting point, glass transition point or softening point of the heat resistant binder more preferably has the same or similar value as that of the fluororesin (a) for the primer layer from the viewpoint that the primer layer can be homogenized.

Examples of the heat-resistant binder include polyphenylene sulfide, polyamide imide, polyimide, polyether sulfone, polyether ether ketone, polyphenylene carbonate and the like, and one or more of them can be used.

As the heat-resistant binder, a solvent-soluble resin is used because it spreads to every corner of the article to be coated and a uniform primer layer having excellent adhesion to the article is obtained. Preferred examples include polyamide imide, polyimide, and polyether sulfone.

The solid content ratio between the fluororesin (a) for the primer layer and the heat resistant binder is 35:65 to 95: 5 as the fluororesin (a) for the primer layer: the heat resistant binder on a mass basis. Preferably there is. When the fluororesin (a) for the primer layer is less than 35:65, the adhesion with the fluororesin lining layer is deteriorated, and delamination is likely to occur. Adhesion is reduced. More preferably 5
0:50 to 95: 5, more preferably 60: 4
It is 0 to 90:10.

The primer layer is used in combination with the fluororesin (a) for the primer layer and the heat resistant binder,
It contains a heat stabilizer. The heat stabilizer is
By being contained in the primer layer, oxidation of the fluororesin (a) for the primer layer and the heat resistant binder due to firing or the like in the method for producing a fluororesin coating film of the present invention can be prevented to prevent thermal deterioration. It is possible to improve the adhesion stability between the article to be coated and the fluororesin lining layer, and even if it is not contained in the fluororesin lining layer, the fluororesin (b) for the lining layer is deteriorated by oxidation. And decomposition can be suppressed.

The heat stabilizer is preferably a combination of the following (1), the following (2), or the following (1) and the following (2) in combination. (1) A metal, a metal oxide and / or an organometallic compound, wherein the metal atom contained in the metal, the metal oxide and the organometallic compound is composed of a plurality of atoms having an atomic number of 26 to 56. Those that are one or more atoms selected from the group. (2) A reducing compound having at least one selected from the group consisting of a nitrogen atom, a sulfur atom and a phosphorus atom, and also a nonmetal.

In the above (1), the metal is a simple substance or an alloy. The metal oxide is one in which the atoms in the molecule are a metal atom and an oxygen atom. The organometallic compound is a compound having at least one metal-carbon bond in the molecule.

The metal atom contained in the metal, the metal oxide, and the organometallic compound means a metal element among a plurality of atoms constituting the metal, the metal oxide, and the organometallic compound, respectively. Belong to. The metal atom contained in the metal in the expression metal atom contained in the metal, the metal oxide and the organometallic compound includes the case where the metal itself is the metal.

The plurality of atoms having the atomic numbers of 26 to 56 are atoms belonging to the metal element among the plurality of elements having the atomic numbers of 26 to 56. Examples of such a metal element include, for example, II-A group, VI-A group, and VII-A.
Examples of the metal element belong to Group I, Group VIII, Group IB, Group II-V, Group IV-B, and the like, and include Mn, Fe, Ni, and C.
o, Cu, Zn, Mo, Pd, Ag, Cd, Sn and B
a is preferable, and Co, Cu, Zn, and Sn are more preferable.

The heat stabilizer belonging to (1) above is not particularly limited as long as it satisfies the above-mentioned conditions and can function as a heat stabilizer. For example, Mn, Fe,
Ni, Co, Cu, Zn, Mo, Pd, Ag, Cd, S
Examples include simple substances such as n and Ba; metal oxides such as CuO, organic carboxylates, organic phosphates, and organic metal compounds such as organic sulfur compounds.

A reducing compound of the above (2), and
The nonmetal is not particularly limited, and examples thereof include amine-based antioxidants and organic sulfur-containing compounds.

As the amine-based antioxidant, 2 in consideration of the firing temperature in the method for producing a fluororesin coating film of the present invention.
Amine compounds that are stable even at 50 ° C. or higher are preferable, and examples thereof include aromatic amines.
A phenyl group such as dinaphthylamine, phenyl-α-naphthylamine, phenyl-β-naphthylamine, diphenyl-p-phenylenediamine, phenylcyclohexyl-p-phenylenediamine, N, N′-di-2-naphthyl-p-phenylenediamine or the like. Amine derivatives having a naphthyl group are preferred.

The organic sulfur compound is not particularly limited, and examples thereof include a mercaptobenzimidazole compound, a mercaptobenzothiazole compound, thiocarbamic acid, salts thereof, and thiuram monosulfide. The salt is not particularly limited, and examples thereof include salts with Zn, Sn, Cd, Cu, Fe and the like.

As the heat stabilizer, one kind or two or more kinds selected from those belonging to each of the above (1) and (2) can be used. The heat stabilizer is preferably a non-metal compound that does not produce a residue, especially when used in the field of pharmaceuticals where elution of metal ions is not desirable, such as semiconductors, for example, among amine-based antioxidants and organic sulfur compounds, Other than metal salts are mentioned.

The heat stabilizer is added in an amount of 0.001 to 0.001 by mass based on the solid content of the fluororesin (a) for the primer layer.
It is preferably 5%. If it is less than 0.001%, the heat-stabilizing effect may be insufficient, and if it exceeds 5%, the effect of foaming caused by the decomposition of the heat-stabilizing agent becomes large and the adhesion becomes a problem. There is. More preferably, it is 0.003 to 2%.

The primer layer may contain additives as required in combination with the above-mentioned components. The above-mentioned additive is not particularly limited, and examples thereof include those used for a general paint primer,
For example, it may be a pigment. The pigment is not particularly limited, and examples thereof include color pigments such as carbon, titanium oxide, rouge, and mica, as well as rust preventive pigments and calcined pigments.

The above-mentioned primer used for forming the above-mentioned primer layer is prepared by dissolving the heat-resistant binder for dissolving the heat-resistant binder together with the fluororesin (a) for the primer layer, the heat-resistant binder and the heat stabilizer. It is preferable to contain a solvent. The heat-resistant resin dissolving solvent is not particularly limited as long as it is a solvent capable of dissolving the heat-resistant binder, but has a boiling point of 100 ° C.
The above are preferable, and examples thereof include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide and the like.

The heat-resistant binder-dissolving solvent is preferably 10% or more by mass of the heat-resistant binder. Within the above range, the heat resistant binder can be spread over the article to be coated as described above, and the adhesion to the article to be coated can be improved. 10%
If it is less than the above range, the heat-resistant binder on the article to be coated becomes non-uniform and the adhesion is poor. More preferably 50
% Or more. When the heat-resistant binder-dissolving solvent increases, the adhesion to the article to be coated tends to improve,
In view of industrial production, it is usually preferably 500% or less, more preferably 350% or less.

The above-mentioned primer preferably further contains a dispersion medium. The primer is a dispersion system (dispersion) in which the heat-resistant binder is dissolved in the heat-resistant binder-dissolving solvent, and the fluororesin (a) for the primer layer is dispersed in the dispersion medium as a dispersoid. Therefore, it is possible to apply it to every corner of the article to be coated.

As the dispersion medium, at least one selected from the group consisting of water, alcohols, ketones, esters and aromatic hydrocarbons is used. As the dispersion medium, water is preferably used from the viewpoint of working environment.

When water is used as the dispersion medium, a surfactant is required to disperse the fluororesin (a) for the primer layer. The surfactant is not particularly limited and may be any of nonionic, anionic or cationic surfactants, but those which evaporate or decompose at a relatively low temperature of about 250 ° C. are preferable, and nonionic surfactants are preferable. And anionic are more preferred.

When water is used as the dispersion medium, a rust preventive agent is necessary in order to prevent corrosion of the coated object during coating. The rust preventive agent is not particularly limited, and examples thereof include dibutylamine.

As the dispersion medium, when the fluororesin (a) for primer layer obtained by emulsion polymerization is used as a dispersion without isolation of the resin component, water used for emulsion polymerization is used as the dispersion medium. It may be used, and in this case, water may be added separately. When the dispersion of the fluororesin (a) for the primer layer obtained by emulsion polymerization is used as it is, the surfactant used for emulsion polymerization may be used as it is as a part or all of the surfactant. Similarly, when the fluororesin (a) for primer layer is obtained by suspension polymerization, the solvent used for suspension polymerization may be used as the dispersion medium as long as it is within the range of the dispersion medium.

The above-mentioned primer can be prepared, for example, by a conventionally known method. For example, the above-mentioned pigment, viscosity adjusting agent, film-forming material, solvent and the like can be mixed to prepare a coating material. As a coating material, these materials may be dispersed at an arbitrary ratio and then adjusted with a viscosity modifier or the like to have a viscosity that facilitates coating.

The above-mentioned pigment is used by pulverizing and dispersing the above-mentioned water, heat-resistant binder, surfactant and the like in a pulverizing and dispersing machine such as a basket mill, a dynamo mill and a ball mill.

The fluororesin (a) for the primer layer is
In the case of the dispersion type, since the average particle size is relatively small, about 0.5 μm, it can be dispersed in the primer as it is. The fluororesin (a) for the dispersion type primer layer includes
Usually, those produced by emulsion polymerization and concentrated with the above-mentioned surfactant are used. When a powder having an average particle size of 1 to 30 μm is used as the fluororesin (a) for the primer layer, it is mixed with the heat resistant binder after wetting the dispersion medium with the surfactant. To do.

When water is used as the dispersion medium, the heat resistant binder is pulverized in the same volume as the pigment, dispersed in water in advance, and then mixed with the primer.
From the viewpoint of production convenience, it is preferable to add the above heat stabilizer when the pigment is pulverized.

The primer layer is formed by applying the primer thus obtained to the object to be coated, heating it if necessary, and drying it.

The material of the article to be coated is not particularly limited as long as it has heat resistance at the firing temperature in the method for producing a fluororesin coating film of the present invention and the heating temperature at the time of use, and examples thereof include iron and aluminum. Examples include metals such as nickel, chromium, and zinc, and alloys including the above metals. The alloy is not particularly limited, and examples thereof include iron alloys such as stainless steel; nickel alloys such as Hastelloy and Inconel. As the material of the above-mentioned object to be coated, galvanized steel, aluminum plated steel,
It may be plated steel such as chrome plated steel.

The above-mentioned article to be coated is not particularly limited as long as it is generally desired to form a lining made of a fluororesin, and, for example, those desired to have corrosion resistance are suitable. Such objects to be coated include, for example, tanks, vessels, towers, valves, pumps, fittings, other piping materials, and other corrosion resistant linings; chemical and medical instruments, wafer baskets, coil bobbin tower packings, Other examples include those that are subjected to other anticorrosion treatments such as chemical valves and pump impellers.

The above-mentioned article to be coated may be one which has been subjected to cleaning, roughening or the like in advance as a pretreatment, if necessary. From the viewpoint of improving the adhesion to the primer layer and preventing deterioration of the fluororesin coating film, it is preferable that the above-mentioned object to be coated is subjected to the above-mentioned pretreatment. As the pretreatment, depending on the type of the object to be coated, for example, oil removal of the object to be coated by degreasing with an alkali or a solvent; chemical etching using hydrochloric acid, sulfuric acid, alkali, etc .; silica sand, A sandblast treatment with alumina powder or the like can be used.

The method of applying the primer to the article to be coated is not particularly limited and can be appropriately selected depending on the form of the article to be coated, for example, spray coating,
Conventionally known methods such as dip coating, brush coating, electrostatic coating and the like can be mentioned. The coating preferably has a thickness of 5 to 200 μm after firing for forming the fluororesin lining layer.
m, more preferably 10 to 100 μm, still more preferably 15 to 50 μm.

The above drying is carried out, for example, at 60 to 150 ° C. for 15 to 60 minutes. The above-mentioned drying may be performed at room temperature in advance before heating, whereby the above heating conditions can be relaxed.

The method for producing a fluororesin coating film of the present invention comprises forming a fluororesin lining layer on the primer layer. The fluororesin lining layer contains a fluororesin (b) for a lining layer.
In the present specification, the fluororesin lining layer,
It is a coating film formed by applying a coating material for a lining containing the above-mentioned fluororesin (b) for a lining layer as a main component, drying it if necessary, and then firing it.

The fluororesin (b) for the lining layer is not particularly limited and is, for example, the same as the fluororesin (a) for the primer layer. Can be used. As the fluororesin (b) for the lining layer, a meltable fluororesin is preferable. From the viewpoint of corrosion resistance, the above-mentioned tetrafluoroethylene-based copolymer is preferable as the polymer forming the fluororesin (b) for the lining layer, and ETFE, FEP and PFA are more preferable.

When PTFE is used as the fluororesin (b) for the lining layer, another polymer that can be used for the fluororesin (b) for the lining layer may be used in combination from the viewpoint of improving the corrosion resistance. preferable.

Even if the fluororesin lining layer does not contain a heat stabilizer, the primer layer contains the heat stabilizer as described above, so that the heat of the fluororesin for the lining layer (b) is not contained. It is possible to prevent deterioration and decomposition. The fluororesin lining layer preferably does not contain the heat stabilizer.

The coating material for the lining applied for forming the fluororesin lining layer is not particularly limited as long as it contains the fluororesin (b) for the lining layer, and is appropriately added if necessary. It may contain other components such as agents.

The above-mentioned other components are preferably contained in the necessary minimum amounts from the viewpoint of fully utilizing the characteristics such as the corrosion resistance of the fluororesin (b) for the lining layer. By reducing the amount of the above-mentioned other components, the fluororesin (b) for the lining layer in the fluororesin lining layer can be highly purified. For example, water and chemicals in semiconductor manufacturing equipment, chemical / medical instruments, etc. It is possible to prevent adverse effects on the contact substance and deterioration of the fluororesin lining layer.

The lining coating material may be a water-based coating material, a solvent-based coating material, a powder coating material, or the like, but from the viewpoint of environmental protection, the water-based coating material and the powder coating material are preferable, and from the viewpoint of thickening the film, powder coating. Body paints are more preferred. As the method for producing the water-based paint and the solvent-based paint, for example, the same method as the method for producing the primer can be used. The method for producing the powder coating material is not particularly limited, and examples thereof include conventionally known methods. For example, after melt-kneading the fluororesin (b) for the lining layer and the other components as necessary, A method of pulverizing and classifying by the method described for the method of pulverizing the fluororesin (a) for primer layer described above can be used.

The fluororesin lining layer is formed by applying the lining coating material on the primer layer, drying it if necessary, and then firing it.

The method of applying the coating material for the lining is not particularly limited, and examples thereof include liquid coating such as water-based coating and solvent coating, spray coating, roller coating and the like, and powder coating. , Electrostatic spray coating, fluid immersion coating, lot lining method and the like. As the above-mentioned coating method, the roto lining is preferable because it is easy to increase the film thickness and the construction time can be shortened.

As a method for applying the lining paint,
In the case of performing electrostatic spray coating, since the coatable film thickness per time is usually as thin as about 50 to 150 μm, it is necessary to repeat the process of coating and firing depending on the desired film thickness. For example, 600 μm, which has high market needs
When obtaining the above film thickness, it is necessary to perform 5 to 10 times.

The firing is performed at a temperature above the melting point, softening point or glass transition point of the fluororesin (b) for the lining layer, and the fluororesin (a) for the primer layer, the heat resistant binder, and the heat stability. It is not particularly limited as long as it is a temperature at which the agent and the fluororesin (b) for the lining layer are not decomposed and the article to be coated is not thermally deteriorated.
It is carried out at 250 to 350 ° C. for 20 to 60 minutes.

The fluororesin lining layer preferably has a film thickness of 100 to 10,000 μm after the firing. If the thickness is less than 100 μm, the excellent characteristics of the corrosion-resistant fluororesin (b) for the lining layer may not be sufficiently exhibited, especially in the case of a corrosion-resistant lining.
If it exceeds 0 μm, cracks may occur. More preferably, it is 200 to 5000 μm.

The ratio (TL / TP) between the film thickness (unit: μm, TL) of the fluororesin lining layer after firing and the film thickness (unit: μm, TP) of the primer layer after firing is: 20-250 are preferable and 30-100 are more preferable.

A processed article having the fluororesin coating film thus obtained and the article to be coated is also one aspect of the present invention. In the processed article, it is preferable that the primer layer contains the heat stabilizer and the fluororesin lining layer does not contain the heat stabilizer.

In the method for producing a fluororesin coating film of the present invention, as described above, since the primer layer contains the heat stabilizer, the fluororesin lining layer does not need to contain the heat stabilizer. Not only the fluororesin for the primer layer (a) but also the fluororesin for the lining layer (b) can be delayed or prevented from thermal degradation and decomposition, and problems such as foaming, embrittlement, and coloring can be avoided. it can. The fluororesin (b) for the lining layer is thermally deteriorated or decomposed, and even when the lower layer in the fluororesin coating film is to be baked several times, as in electrostatic coating, Can be prevented.

In the method for producing a fluororesin coating film of the present invention, since the fluororesin lining layer does not contain the heat stabilizer, the heat stabilizer such as a metal ion or a substance derived from the heat stabilizer is not used at the time of use. Since it does not exude, problems such as electronic interference in semiconductor manufacturing facilities and alteration of chemicals in chemical / medical instruments and the like do not occur.

In the method for producing a fluororesin coating film of the present invention, the fluororesin (b) for the lining layer can be prevented from being deteriorated by heat or decomposed even in overcoating as described above, so that the film thickness can be increased. Further, since the primer layer is formed easily, the adhesion between the article to be coated and the fluororesin lining layer can be improved.

Therefore, the method for producing a fluororesin coating film of the present invention is suitably used for the construction of a corrosion-resistant lining where a thick film is usually desired, and the fluororesin lining layer does not contain the heat stabilizer, whereby metal ions, etc. It is particularly preferably used in the field where exudation of the above heat stabilizer or its derived substance is not desired. Examples of such fields include semiconductor manufacturing fields such as semiconductor manufacturing equipment, semiconductor chemical manufacturing equipment, and semiconductor chemical containers; pharmaceutical manufacturing equipment, pharmaceutical containers,
Chemical and medical fields such as chemical manufacturing equipment and chemical containers;
Examples include fields for food products such as alcohol brewing containers, fermented food brewing containers, and fermented food storage containers.

A fluororesin coating film manufactured by the above-mentioned fluororesin coating film manufacturing method is also one aspect of the present invention. An object to be coated, which has the fluororesin coating film, is also one aspect of the present invention.

[0089]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Formulation Example 1 Ethylene _{Tetrafluoroethylene:} CH 2 = CFC ₃
Average particle size 10 with a F ₆ H molar ratio of 33: 65: 2 and a melt flow rate at 300 ° C. of 8 g / 10 min.
30 g of ETFE-based copolymer powder of μm, PAI powder 10 which is a pulverized product of polyamideimide (PAI; manufactured by Hitachi Chemical Co., Ltd.) having a mean particle size of 1.5 μm as a heat resistant binder.
g, 0.7 g of HS-208 (manufactured by NOF CORPORATION) as a nonionic surfactant, 0.1 g of dibutylamine and pure water 2
5 g was put in a stainless steel container, well stirred at 300 rpm for 20 minutes using a propeller stirrer, then 20 g of N-2-pyrrolidone was well dispersed while stirring, and copper oxide (CuO) having an average particle diameter of about 1 μm was used as a heat stabilizer. 200 m
g was added and stirred for 10 minutes to obtain a primer for re-ETFE containing a heat stabilizer.

Formulation Example 2 A primer for ETFE containing a heat stabilizer was obtained in the same manner as in Formulation Example 1 except that the heat stabilizer was changed to 500 mg of N, N'-di-2-naphthyl-p-phenylenediamine.

Formulation Example 3 A heat stabilizer was used as a 2-mercaptobenzothiazole zinc salt 50.
A primer for ETFE containing a heat stabilizer was obtained in the same manner as in Formulation Example 1 except that the primer was changed to 0 mmg.

Formulation Example 4 As the heat stabilizer, 200 mg of copper oxide (CuO) and N, N'- were used.
Di-2-naphthyl-p-phenylenediamine 500 mg
A ETFE primer containing a heat stabilizer was obtained in the same manner as in Formulation Example 1 except that the above was changed to.

Formulation Example 5 Instead of the ETFE type copolymer, a powder having a melt flow rate of 2.5 g / 10 minutes and an average particle size of 7.5 μm was used, which was composed of tetrafluoroethylene: perfluoro (propyl vinyl ether). A tetrafluoroethylene / hexafluoropropylene copolymer [FEP] and a primer containing a heat stabilizer for PFA were obtained in the same manner as in Formulation Example 4 except that PFA having a mass ratio of 99.5: 0.5 was used. .

Blending Example 6 Instead of the ETFE copolymer, a polytetraethylene emulsion polymer (solid content: 60% by mass, average particle size 0.25 μ)
m) F was prepared in the same manner as in Formulation Example 2 except that 70 g was used.
A primer containing a heat stabilizer for EP and PFA was obtained.

Formulation Example 7 Polyether sulfone resin (PE
S; manufactured by Sumitomo Chemical Co., Ltd.) 7 g of pulverized product having an average particle diameter of about 2 μm
And a primer for ETFE containing a heat stabilizer was obtained in the same manner as in Formulation Example 1 except that the PAI powder used in Formulation Example 1 was changed to 3 g.

Formulation Example 8 The heat resistant binder of Formulation Example 5 was changed to 7 g of a pulverized product of a polyether sulfone resin (PES; manufactured by Sumitomo Chemical Co., Ltd.) having an average particle diameter of about 2 μm and 3 g of PAI powder used in Formulation Example 1. Formulation example 5 except that the heat stabilizer was changed to 500 mg of N, N'-di-2-naphthyl-p-phenylenediamine
A primer containing a heat stabilizer for FEP and PFA was obtained in the same manner as in.

Formulation Example 9 A heat stabilizer for FEP and PFA was prepared in the same manner as in Formulation Example 8 except that the heat-resistant binder was changed to 10 g of a pulverized product of polyimide resin (PI; manufactured by Hitachi Chemical Co., Ltd.) having an average particle diameter of 1.5 μm. A filled primer was obtained.

Formulation Examples 10 to 15 The materials used in Formulation Examples 1 to 9 were used as shown in Table 1, and with or without a heat stabilizer for ETFE.
Primers for P and PFA were obtained.

[0099]

[Table 1]

In Table 1, stabilizer A is copper oxide (Cu
O), stabilizer B is N, N′-di-2-naphthyl-p-phenylenediamine, stabilizer C is 2-mercaptobenzothiazole zinc salt, and stabilizer D is the above stabilizer A 20.
Represents a mixture of 0 mg and 500 mg of Stabilizer B above.

Examples 1 to 14 and Comparative Examples 1 to 4 (Coating for Lining) As the coating for lining for forming the fluororesin lining layer, the following coatings were selected and used as shown in Table 2. - as ETFE powder coating, ethylene: tetrafluoroethylene: _CH 2 = C
FC ₃ F ₆ H molar ratio is 45: 53: 2, 300
An ETFE powder coating composition containing a stabilizer, which has a melt flow rate at 10 ° C. of 10 g / 10 minutes and is an ETFE copolymer having an average particle diameter of 65 μm. -As FEP powder paint, NC-1500 (FEP clear paint, manufactured by Daikin Industries) -As PFA powder paint, AC-5600 (PFA clear paint, manufactured by Daikin Industries, Ltd.)

(Construction) SUS304 having a length of 200 mm × width of 300 mm × thickness of 2 mm was degreased with acetone, and 60 mesh alumina (trade name: Tosa Emery, manufactured by Uji Denki Kagaku Kogyo Co., Ltd.) was used as a blast air pressure. .5
The surface was roughened with MPa, and the primer obtained by the formulation example shown in Table 2 was applied using a 1.2φ spray gun so that the average thickness after firing was 26 μm, and dried at 80 ° C. for 30 minutes. Next, as shown in Table 2, the above powder coating material was used with a spacer so that the thickness after firing was 2 mm.
The sample was placed on an area of mm × 50 mm and fired at the firing temperature shown in Table 2 for 1 hour, 5 hours, 10 hours, 20 hours and 30 hours.

(Evaluation) The degree of foaming of the coating film after each of the above firing times was visually examined as compared with that before firing, and evaluated according to the following criteria. The results are shown in Table 2. ◎ There was no foaming. -Some bubbles were generated. × Many bubbles were formed.

[0104]

[Table 2]

From Table 2, in each of Examples 1 to 14 in which the above-mentioned heat stabilizer was contained in the primer, the state of the coating film after baking was relatively good, but the above-mentioned heat stabilizer was not contained in the primer. It was found that in Examples 1 and Comparative Example 2, a large number of bubbles were generated only by baking for 5 hours, and in Comparative Examples 3 and 4 in which no primer was used, foaming was generated only by baking for 1 hour. The fluororesin coating film was used in Comparative Example 3
However, in Comparative Example 4, when it was left for half a day, it spontaneously peeled from the substrate.

[0106]

EFFECTS OF THE INVENTION Since the method for producing a fluororesin coating film of the present invention has the above-mentioned constitution, the fluororesin for the lining layer (b) can be obtained without the need to include the heat stabilizer in the fluororesin lining layer. It is possible to prevent thermal deterioration and avoid foaming, embrittlement, coloring, etc. Also, by not containing the thermal stabilizer in the fluororesin lining layer, electronic interference in semiconductor manufacturing equipment, chemical / medical devices It is possible to prevent the deterioration of chemicals in the above.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B05D 7/22 B05D 7/22 P C09D 5/00 C09D 5/00 D 127/12 127/12 201/00 201/00 (72) Inventor Toshio Miyatani No. 1-1 Nishiichitsuya, Settsu-shi, Osaka Daikin Industries Ltd. Yodogawa Manufacturing Co., Ltd. (72) Inventor Koichiro Ogita No. 1 Nishiichitsuya, Settsu-shi Osaka Prefecture Yodogawa Manufacturing Co., Ltd. Inner F-term (reference) 4D075 AA01 CA17 CA33 DA13 DB02 DC30 EA41 EB16 4J038 CB032 CD091 CD092 CD111 CD112 CD121 CD122 CD131 CD132 CE051 CE052 DE011 DE012 DJ021 DJ022 DJ051 DJ062 MA06 J02MA06 J02MA06 J02MA06 J021812 MA10 MA12 MA13 MA14 NA11 NA12 NA24 NA27 PB02 PB06 PB09 PC02

Claims (11)

[Claims] 1. A method for producing a fluororesin coating film comprising forming a primer layer and forming a fluororesin lining layer on the primer layer, wherein the primer layer comprises: A fluororesin (a) for a primer layer, a heat resistant binder and a heat stabilizer, and the fluororesin lining layer comprises
A method for producing a fluororesin coating film, which comprises a fluororesin (b) for a lining layer. 2. The method for producing a fluororesin coating film according to claim 1, wherein the fluororesin (a) for the primer layer is a tetrafluoroethylene-based copolymer. 3. The method for producing a fluororesin coating film according to claim 1, wherein the heat-resistant binder is composed of a polymer substance having a melting point, a glass transition point or a softening point of 180 ° C. or higher. 4. The heat stabilizer is a metal, a metal oxide and / or an organometallic compound, and the metal atom contained in the metal, the metal oxide and the organometallic compound is 26 to
The method for producing a fluororesin coating film according to claim 1, 2 or 3, which is one or more atoms selected from the group consisting of a plurality of atoms having an atomic number of 56. 5. The heat stabilizer is a reducing compound having at least one selected from the group consisting of a nitrogen atom, a sulfur atom and a phosphorus atom, and is a nonmetal.
The method for producing a fluororesin coating film according to 2 or 3. 6. The heat stabilizer includes the following (1) and (2)
The method for producing a fluororesin coating film according to claim 1, 2 or 3, which is used in combination. (1) A metal, a metal oxide and / or an organometallic compound, wherein the metal atom contained in the metal, the metal oxide and the organometallic compound is composed of a plurality of atoms having an atomic number of 26 to 56. Those that are one or more atoms selected from the group. (2) A reducing compound having at least one selected from the group consisting of a nitrogen atom, a sulfur atom and a phosphorus atom, and also a nonmetal. 7. The method for producing a fluororesin coating film according to claim 1, wherein the fluororesin lining layer is baked and has a thickness of 100 to 10000 μm. 8. A fluororesin coating film produced by the method for producing a fluororesin coating film according to claim 1, 2, 3, 4, 5, 6 or 7. 9. An article to be coated, comprising the fluororesin coating film according to claim 8. 10. A processed article having an article to be coated and a fluororesin coating film, the fluororesin coating film forming a primer layer on the article to be coated, and a fluororesin lining on the primer layer. It is made up of layers,
The primer layer is a fluororesin for primer layer (a)
And a heat stabilizer, wherein the fluororesin lining layer contains the fluororesin (b) for a lining layer and does not contain a heat stabilizer. 11. The processed article according to claim 10, wherein the fluororesin lining layer is fired and has a thickness of 100 to 10,000 μm.