WO2004065504A1 - Powder coating composition, method of forming coating film, and layered product - Google Patents

Abstract

A powder coating composition which can give a coating film satisfactory in adhesion to the substrate and surface smoothness without the necessity of using a primer or roughening the surface of the substrate. The powder coating composition comprises a fluororesin and is characterized in that the fluororesin has a melting point of 150 to 250°C and shows a melting peak having a half-value width of 30°C or more.

Description

 Specification

 Powder coating, coating film forming method and laminate

 The present invention relates to a powder coating, a coating film forming method, and a laminate. Background art

 Fluororesin is excellent in chemical resistance, corrosion resistance, etc., and is used in applications where a film made of fluororesin is formed on a substrate for the purpose of protecting the substrate from corrosion of chemicals, etc. Sometimes.

 Fluororesin, when forming a film in this way, can be applied according to various shapes of the base material, and the amount of waste is small at the time of application and the handling is easy. Often used as

 The powder coating is usually applied to a substrate using a method such as electrostatic powder coating or rotational molding, and is subjected to a suitable heat treatment to form a coating film. In the following, applying a powder coating material to a substrate to obtain a coating film and performing an appropriate heat treatment is referred to as “painting”. In general, fluororesin has low adhesiveness to a substrate, so that a fluororesin powder coating is applied on a substrate to improve the adhesion between the substrate and a coating film obtained by applying the powder coating. It is known to perform a surface roughening treatment such as sandblasting, or to form a coating film by mixing a fluororesin with a resin such as polyphenylene sulfide (for example, Japanese Patent Publication No. 52-4 See Japanese Patent Application Publication No. 174104.)

 To obtain a fluororesin coating film with good adhesion to the substrate, it is also necessary to apply a primer on the substrate to form a primer layer, and then apply a fluororesin powder coating. It was done.

 The fluororesin coating film obtained using the primer is obtained by applying a fluororesin powder coating on the primer layer obtained by applying a fluororesin to which an aromatic resin has been added on a substrate. (See, for example, Japanese Patent Application Laid-Open No. 8-300560).

However, with the use of primers, impurities in the primer There is a problem that the surface appearance of the base material itself, such as color or pattern, cannot be used depending on the use, and that the work may be complicated. Therefore, a powder coating of a fluororesin that can provide a coating film having excellent adhesion to a substrate without using a primer has been desired.

 As the fluorine resin powder coating, an ethylene / tetrafluoroethylene-based copolymer for rotational molding, an ethylene Z-tetrafluoroethylene-based copolymer having a specific viscosity, particle size and specific gravity, etc. are disclosed. (See, for example, Japanese Patent Application Laid-Open No. 5-271508 and Japanese Patent Application Laid-Open No. 11-269274). In the examples, these fluororesin powder coatings are coated on a substrate without using a primer.

 Further, as a fluororesin, a tetrafluoroethylene-based copolymer is disclosed (see, for example, International Publication No. 98/58973 pamphlet). It is described that this tetrafluoroethylene-based copolymer can be made into a powder and laminated on a substrate by electrostatic coating or the like.

 Further, as a fluorine resin, it is described that an ethylene / tetrafluoroethylene-based copolymer having improved moldability during extrusion molding can be formed by coating (for example, Japanese Patent Application Laid-Open No. 200-200). 0—see Japanese Patent Application Publication No. 2004-205).

 However, when these fluororesin powder coatings or fluororesin powders are applied on a substrate without using a primer, when they are applied on a substrate without surface roughening treatment such as sandblasting However, there was a problem that the adhesion between the coating film and the substrate was insufficient. Summary of the Invention

 The purpose of this effort is to provide a coating film that has good adhesion to the substrate and surface smoothness without using primers or performing surface roughening treatment on the substrate in view of the above situation. An object of the present invention is to provide a powder coating that can be obtained.

 The present invention is a powder coating comprising a fluororesin, wherein the fluororesin has a melting point of 150 to 260 ° C and a half-value width of a melting point at an insecticidal peak of 30 ° C or more. It is a powder coating characterized by the following.

The present invention is a powder coating comprising a fluororesin, wherein the powder coating is obtained from the fluororesin. Three

The powder coating is characterized in that the shrinkage of the measuring coating film is 2% or less.

 The present invention provides a coating film forming method for forming a coating film using the powder coating, wherein the powder coating is applied to a substrate, and a heat treatment is performed at a heating temperature that is equal to or higher than the melting point of the fluororesin. A method for forming a coating film, comprising a step of performing.

 The present invention is a laminate comprising a base material, and a coating film obtained by applying the powder coating material on the base material and performing a heat treatment. Detailed Disclosure of the Invention

 Hereinafter, the present invention will be described in detail.

 The powder coating of the present invention is made of a fluororesin.

 The powder coating material of the present invention comprises a fluororesin and satisfies the following condition (1) and / or the following condition (2).

 Conditions (1) The fluororesin has a melting point of 150 to 260 ° C and a half-value width of a melting point at a melting peak of 30 ° C or more.

 Condition (2) The shrinkage of the coating film for measurement obtained from the fluororesin is 2% or less. The powder coating material of the present invention only needs to satisfy at least one of the condition (1) and the condition (2), and may satisfy both the condition (1) and the condition (2). Good.

 Under the above condition (1), if the melting point is less than 150 ° C, the heat resistance is insufficient for some applications. If the temperature exceeds 260 ° C., it is not preferable because the heating temperature described below cannot be lowered and the range of selection of the substrate on which the powder coating can be applied is narrowed. The melting point of the fluororesin is preferably 155 ° C, more preferably 160 ° C, more preferably 230 ° C, preferably 220 ° C, and more preferably 200 ° C. Is a more preferred upper limit.

In the present specification, the above-mentioned melting point is a value obtained by measuring with a differential scanning calorimeter [DSC] (manufactured by Seiko) according to the following method. That is, the melting peak of the fluororesin when the temperature is raised at a rate of 10 ° C / min is recorded, and the maximum value is detected based on the baseline. When a line parallel to the baseline touches the melting peak at a clear point, the point is defined as the maximum value, and the temperature at the maximum value is defined as the melting point. Melting with the above parallel lines Four

When the point of contact with the peak is not clear, a point that is considered to have a maximum value is set as a tentative point, and a line parallel to the baseline is drawn at half the peak height indicated by the tentative point, and this line is melted as described above. The melting point is the temperature at the intersection of the melting peak with the line perpendicular to the baseline, passing through the central point between the two points that intersect peak '.

 In the above condition (1), the powder coating material has a half-value width of a melting point at a melting peak of the fluororesin of 30 ° C. or more. The `` half width of the melting point at the melting peak '' is defined as half the peak value or half the peak height at the point where the peak is considered to be the maximum value in the melting point measurement method. It is the temperature difference between two points that intersect the melting peak when a parallel line is drawn. It is preferable that the powder coating has a half-value width of the melting point at the melting peak of the fluororesin within the above range, since the obtained coating film has good adhesion to the substrate.

 The above condition (2) is “the shrinkage of the coating film for measurement obtained from the fluororesin is 2% or less” as described above. It is not preferable because the surface smoothness decreases. The shrinkage is preferably 1% or less in view of the adhesiveness and surface smoothness of the obtained coating film. The shrinkage is preferably 0%, but within the above range, the resulting coating film has good adhesion and surface smoothness, and there is no practical problem.

 In the present specification, the above-mentioned shrinkage ratio is a value obtained by measuring a coating film (hereinafter, referred to as a “coating film for measurement”) obtained by the following method for measuring a shrinkage ratio. . That is, a release agent having heat resistance (for example, Die Free manufactured by Daikin Industries, Ltd.) is applied to the surface of a SUS base material having a surface roughness (R a) of 0.1 Xm or less. The above fluororesin powder is electrostatically coated on a section of 3 cm in length and 3 cm in width so that the film thickness becomes 150 μηι. Thereafter, the coating is heated at a temperature 60 ° C. higher than the melting point of the fluororesin for 30 minutes to obtain a coating film. The resulting coating film is immersed together with the substrate in hot water at about 9.8 ° C for about 12 hours to peel off the coating film from the substrate without applying external force to obtain a coating film for measurement. Measure the length and length of the obtained coating film for measurement and average them to calculate the shrinkage.

When the powder coating material of the present invention satisfies the above condition (1), satisfies the above condition (2), and satisfies the above condition (1) and the above condition (2) The following is a description of items common to both cases.

The fluororesin is made of a polymer having a monomer unit derived from a fluorine-containing monomer. The fluororesin may be a polymer having a monomer unit derived from a fluorine-containing monomer and a monomer unit derived from a fluorine-free monomer. The fluorine-containing monomer and the non-fluorine-containing monomer may each be one kind or two or more kinds. In the present specification, the “unit” is a part of the molecular structure of the polymer, and means a part derived from a monomer. For example, Te trough Ruo ii ethylene unit described later, -CF ₂ - CF ₂ - is represented by the ethylene units of the later one CH ₂ - CH ₂ - is represented by.

 The fluororesin has the following general formula (I)

CX ¹ ₂ = CY ^ R f '-Ζ ¹ (I)

(In the formula, X ¹ , Y ¹ and Z ¹ are the same or different and each represent a hydrogen atom or a fluorine atom, and R f ¹ is an alkylene group having 1 to 40 carbon atoms, and a fluorine-containing group having 1 to 40 carbon atoms. A monomer having a xyalkylene group, a fluorinated alkylene group having 1 to 40 carbon atoms having an ether bond, or a fluorinated oxyalkylene group having 1 to 40 carbon atoms having an ether bond. A monomer derived from a) may have a (a) unit.

 The monomer (a) is represented by the following general formula (II)

CF ₂ = CF-R f ² (II)

(In the formula, R f ² is a perfluoroalkyl group having 1 to 40 carbon atoms, a perfluorooxyalkyl group having 1 to 40 carbon atoms, a perfluoroalkyl group having 1 to 40 carbon atoms having an ether bond, Or a perfluorooxyalkyl group having 1 to 40 carbon atoms having an ether bond.) A monomer (a1) represented by the formula (1), wherein the monomer (a) has a fluorine atom: A monomer different from the monomer (al) (hereinafter, sometimes referred to as “monomer (a 2) j)”; and a compound represented by the following general formula (III): CH ₂ = CH-R f ³ (III )

(In the formula, R f ³ is an alkyl group having 1 to 40 carbon atoms, an oxyalkyl group having 1 to 40 carbon atoms, an alkyl group having 1 to 40 carbon atoms having an ether bond, or a carbon number having an ether bond. Represents an oxyalkyl group of 1 to 40.) 3) Includes'. The monomer (a3) is a monomer having no fluorine atom among the monomers (a).

 In the present specification, the above-mentioned “fluorine-containing monomer” is an unsaturated compound obtained by substituting at least a part of a hydrogen atom bonded to a carbon atom with a fluorine atom. Examples of the fluorine-containing monomer include tetrafluoroethylene, a perfluoro monomer such as the monomer (a1); the monomer (a2), bilidene fluoride, and trifluorochloro Other fluoromonomers (excluding the above-mentioned perfluoromonomer) such as ethylene, chlorotrifnoreoethylene, vinyl fluoride, and hexafluoroisobutylene.

 In the present specification, the “fluorine-free monomer” is a monomer having a carbon-carbon double bond and having no fluorine atom. Examples of the fluorine-free monomer include the above-mentioned monomer (a3), Shiridani Bier, vinylidene chloride and the like. As the monomer (a3), for example, those having 5 or less carbon atoms are preferable. Examples of such monomers include ethylene [Et], propylene [Pr], 1-butene, 2- Butene and the like.

In the present specification, a “fluorinated oxyalkylene group” as R f in the above general formula (I) and R f ⁴ in the following general formula (IV), R i ² in the above general formula (II) And the “oxyalkyl group” as R f ³ in the general formula (III) described above is an oxygen bonded to a carbon atom constituting a carbon-carbon double bond. It has an atom. In the present specification, “having an ether bond” with respect to the above R f R f R f ³ and R f ⁴ means that ^one R ¹ R f R f ³ and R f ⁴ has one C in its main chain. It means having a bond represented by one O-C one. One or more oxygen atoms constituting the bond represented by the above C 1 O—C 1 are present in the main chain constituting the above R f \ R f R f ³ and R f ⁴ It may be. Therefore, for example, as R f ¹ in the above general formula (I), “a fluorinated oxyalkylene group having 1 to 40 carbon atoms having an ether bond” constitutes a carbon-carbon double bond in the above general formula (I). And an oxygen atom constituting a bond represented by 1 C—O—C 1 in the main chain constituting R f ¹ . The fluororesin is preferably a resin made of a tetrafluoroethylene-based copolymer having a tetrafluoroethylene unit from the viewpoint of utilizing the properties of the fluororesin. As the tetrafluoroethylene-based copolymer, tetrafluoroethylene units and tetrafluoroethylene / ethylene copolymers having ethylene units are preferred, and the tetrafluoroethylenenoethylene copolymer is From the viewpoint that the adhesiveness between the obtained coating film and the substrate is good, those having a monomer (a) unit derived from the above-mentioned monomer (a) are preferable. The above tetrafluoroethylene / ethylene copolymer may be one having one or more monomer (a) units derived from the above monomer (a). Examples of the monomer (a) represented by the above general formula include hexafluoro propylene, perfluoro (alkynolebininole-tenor), perfluoro (1,1,5-trihydryl 11-pentene), par Fluorobutylethylene and the like can be mentioned. '

 In the above-mentioned tetrafluoroethylene / ethylene copolymer, the monomer (a) can improve the adhesiveness of the obtained coating film and, depending on the application, the transparency and flexibility of the coating film. It is preferable that the above-mentioned monomer (a 1) and the above-mentioned monomer (a 2) are used in combination from the viewpoint of improving the properties.

 In the above tetrafluoroethylene / ethylene copolymer, the monomer (a) is preferably composed of hexafluoropropylene. The monomer (a) may be hexafluoropropylene, or the above monomer (a) different from hexaf / leo-mouth propylene and one or more hexafluoropropylenes a).

The tetrafluoropropoxy O b / ethylene copolymer, in terms adhesion between the coating film and the substrate obtained is good, tetrafurfuryl O b ethylene unit 3 5-8 1 mole _^0/0, E Ji Ren units 6-5 0 mole _^0/0, and the monomer (a) units 5-5 9 moles ⁰ /. What consists of is preferable. The tetrafluoropropoxy O b / ethylene copolymer, Tetorafunore old port ethylene unit 3 5-8 1 mole _^0/0, ethylene unit 6-5 0 mole _^0/0, and the monomer (a) units 5 mole % Or more and less than 15 mol% (hereinafter, may be referred to as “tetrafluoroethylene / ethylene copolymer (2) J”). However, from the viewpoint of the surface smoothness of the obtained coating film, tetrafluoroethylene unit is ^{35 to} 81 mol 0/0. , Echiren unit 6-5 0 mole _^0/0, and a copolymer having a monomer (a) units 1 5-5 9 molar _^0/0 (hereinafter, "tetrafurfuryl O b / ethylene copolymer (1) Sometimes referred to as J.) is preferable.

 In the present specification, each mole% of each monomer unit is proportional to the number of moles of the monomer added to the copolymer, and is a monomer constituting a molecular chain of the copolymer. In the total number of units, the number excluding the number of monomer units derived from the adhesive functional group-containing monomer described later is defined as 100 mol%, and each unit in the 100 mol% is 100 mol%. It is the ratio of the number of monomer units.

 As the fluororesin, a tetrafluoroethylene unit and the monomer (a) are preferable in that they can improve the adhesion between the obtained coating film and the base material and, depending on the application, are excellent in corrosion resistance and heat resistance. It may be a resin comprising a copolymer having a monomer (a 1) unit derived from 1) (hereinafter sometimes referred to as “perfluoro-based copolymer”).

 The monomer (a 1) is preferably composed of hexafluoropropylene from the viewpoint of utilizing the properties of the fluororesin. The monomer (al) may be hexafluoropropylene, or the above monomer different from hexafluoropropylene and one or more hexafluoropropylenes (Al).

The monomer (a 1) is preferably composed of perfluoro (alkyl vinyl ether) from the viewpoint of heat resistance of the obtained coating film. The monomer (a 1) may be perfluoro (alkyl vinyl ether), or may be different from perfluoro (alkyl vinyl ether) and one or more kinds of perfluoro (alkyl vinyl ether). It may be a monomer (al). As the above perfluoro (alkyl vinyl ether), those having 1 to 10 carbon atoms of a perfluorooxyalkyl group as R f ² in the above general formula (II) are preferable, and those having 1 to 4 are preferable. More preferred.

The above-mentioned perfluoro-opening copolymer has a tetrafluoroethylene unit content of 30 to 93 mol ⁰ / in terms of good adhesion between the obtained coating film and the substrate. And those consisting of the monomer (al) units 7-7 0 mole _^0/0 are preferred. The fluororesin preferably has an adhesive functional group. In the present specification, the term “adhesive functional group” refers to a part of the molecular structure of the polymer contained in the fluororesin, which is capable of participating in the adhesion between the fluororesin and the substrate. means. The concept of the above-mentioned adhesive functional group includes not only a functional group usually called a functional group but also a structure usually called a bond such as an ether bond as long as it can participate in such adhesiveness. It is. The adhesive functional group may be present in the side chain of the polymer contained in the fluororesin, may be present in the main chain, or may be present in the main chain. It may be present at the terminal.

The adhesive functional group is not particularly limited as long as it can participate in the adhesiveness between the fluororesin and the substrate, and examples thereof include a carbonyl group, a hydroxyl group, and an amino group. In the present specification, the “carbonyl group” is a divalent carbon group composed of a carbon-oxygen double bond, and is represented by one represented by 1 C (= 0) —. The carbonyl group is not particularly limited, and examples thereof include a carbonate group, a halogeno formyl group, a formyl group, a carboxyl group, an ester bond [-C (= o) o—], an acid bond [_C (= θ) OC ( = 0) —], isocyanate group, amide group, imido group [— C (= 0) -NH-C (= θ) one], urethane bond [-NH-C (= 0) O—], force Rubamoiru group [NH ₂ -C (= 0) one], Kano lever Moyle O dimethylvinylsiloxy groups _{[NH 2 -C (= θ)} O-], Ureido, group [NH ₂ -C (-0) one NH-, Oxamoyl group [NH ₂ — C (= 0) -C (= 0) ―] and a part of its chemical structure.

The carbonate group is represented by one OC (= 0) OR ¹ (wherein, R ¹ represents an organic group). Examples of the organic group represented by R ¹ in the above formula include an alkyl group having 1 to 20 carbon atoms, an alkyl group having 2 to 20 carbon atoms having an ether bond, and the like, and an alkyl group having 1 to 8 carbon atoms, ether It is preferably an alkyl group having 2 to 4 carbon atoms having a bond. Examples of the above carbonate group include one OC (= θ) OCH ₃ , one OC (= 0) OC ₃ H ₇ , one OC (= 0) OC ₈ H ₁₇ , and — OC (= 0) OCH ₂ CH ₂ CH ₂ OCH ₂ CH ₃ is preferred. The amide group has the following general formula

(Wherein, R ² represents a hydrogen atom or an organic group, and R ³ represents an organic group.).

 The hydrogen atom bonded to the nitrogen atom such as the amide group, imido group, urethane bond, carbamoyl group, carbamoyloxy group, ureido group, oxamoyl group is substituted by a hydrocarbon group such as an alkyl group. Is also good.

 The above-mentioned adhesive functional group is preferably an amide group, a carbamoyl group, or a hydroxyl group, because it is easy to introduce, and the obtained coating film has appropriate heat resistance and good adhesion at a relatively low temperature. , A carboxyl group and a carbonate group are preferred, and among them, a carbonate group is more preferred.

 When the fluororesin has an adhesive functional group, the fluororesin may be a polymer having the adhesive functional group at either a main chain terminal or a side chain, or a main chain terminal. And a polymer having both side chains. When the functional group has an adhesive functional group at the terminal of the main chain, it may be present at both ends of the main chain or at only one of the terminals. The reason that the fluororesin made of a polymer having an adhesive functional group at the terminal of the main chain does not significantly reduce mechanical properties and chemical resistance, or is advantageous in terms of productivity and cost. Is preferred. When the fluororesin is made of a polymer having an adhesive functional group in a side chain, the adhesive functional group-containing monomer is mixed with a fluorine-containing monomer of a type and a blend according to the intended fluororesin. It can be obtained by copolymerization with a monomer and a monomer containing no Z or fluorine. In this specification, the “adhesive functional group-containing monomer” means a monomer having an adhesive functional group. The above-mentioned monomer having an adhesive functional group may or may not have a fluorine atom, but the above-mentioned fluorine-containing monomer and fluorine-free monomer have an adhesive function. It does not have a functional functional group. In this respect, it is conceptually distinguished from an adhesive functional group-containing monomer having an adhesive functional group.

As the adhesive functional group-containing monomer, the following general formula (IV) CX ² ₂ = CY ^2- (R f ⁴ ) _n — Z ² (IV)

(In the formula, z ² represents a functional group having a hydroxyl group, a sulfonyl group or an amino group, ² and ² are the same or different and represent a hydrogen atom or a fluorine atom, and R _f ⁴ is a carbon atom. An alkylene group having 1 to 40 carbon atoms, a fluorinated oxyalkylene group having 1 to 40 carbon atoms, a fluorine-containing alkylene group having 1 to 40 carbon atoms having an ether bond, or a fluorine-containing alkylene group having 1 to 40 carbon atoms having an ether bond Represents an oxyalkylene group, and n represents 0 or 1.) An unsaturated compound represented by the formula: In the present specification, the “functional group having a hydroxyl group, a carbonyl group or an amino group” may be a hydroxyl group, a carbonyl group, or an amino group. This means that a functional group having any of these adhesive functional groups may be used.

 The adhesive functional group-containing monomer may be an unsaturated dibasic acid monoester, vinylene carbonate, maleic anhydride, maleic acid, or the like.

When the fluororesin is a polymer having an adhesive functional group at the terminal of the main chain, and the above-mentioned adhesive functional group is a polymer having a carbonate group, the polymer is obtained by polymerizing oxycarbonate. It can be obtained by a method of performing polymerization using an initiator. The use of the above method is preferable in that the introduction and control of the introduction of the carbonate group are very easy, and the quality is economical, heat resistance, chemical resistance and the like. The above-mentioned peroxycarbonate has the following formula

R— 0—— C—— O—— O—— C—— 0 to R "

 II II

 o o

(Wherein, R ⁴ and R ⁵ are the same or different and each have a linear or branched monovalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a carbon atom having an alkoxyl group at a terminal having 1 to 1 5 represents a linear or branched monovalent saturated hydrocarbon group, R ⁶ represents a linear or branched divalent saturated hydrocarbon group of from 1 1 to 5 carbon atoms, or an alkoxyl group at the terminal A linear or branched divalent saturated hydrocarbon group having 1 to 15 carbon atoms.).

 Among these, the above-mentioned peroxycarbonates include diisopropylpropylcarbonate, di-n-propylperoxydicarbonate, t-butyltinoxyperoxydicarbonate, bis (4-t-butynolec hexyl) ') Peroxydicarbonate, di- 12_ρ-ethynolehexyl' Peroxydicarbonate and the like are preferred.

When the fluororesin is a polymer having an adhesive functional group at a main chain terminal, and the adhesive functional group is a polymer other than a carbonate group, the above-mentioned carbonate group is introduced. In the same manner as in the case where the polymerization is performed, peroxides such as peroxycarbonate, peroxydicarbonate, peroxyester, Adhesive functional groups can be introduced. In addition, “derived from peroxide” means that the force directly introduced from the functional group contained in the peroxide or indirectly by converting the functional group directly introduced from the functional group contained in the peroxide. Means being introduced.

 The amount of the polymerization initiator used such as peroxycarbonate and peroxyester varies depending on the type and composition of the intended fluororesin, the molecular weight, the polymerization conditions, the type of the initiator used, and the like. The amount is preferably 0.05 to 20 parts by mass with respect to 100 parts by mass, a particularly preferred lower limit is 0.1 part by mass, and a particularly preferred upper limit is 10 parts by mass.

The polymerization method for obtaining the above fluororesin is not particularly limited, and includes, for example, conventionally known polymerization methods such as solution polymerization, emulsion polymerization and bulk polymerization.Industrial use of a fluorine-based solvent, Suspension polymerization in an aqueous medium using peroxycarbonate or the like as an agent is preferred. In suspension polymerization, a fluorine-based solvent can be used by adding it to water. The fluorine-based solvent used in the suspension polymerization, for example, _{CH 3 CC 1 F 2, CH} 3 CC 1 2 F, CF 3 CF 2 CC 1 2 H, Haidorota every mouth Furuoroarukan such _{CF 2 C 1 CF 2 C FHC} 1 Fluoroalkanes such as CF ₂ C 1 CFC 1 CF ₂ CF ₃ , CF3CFC I CFC I CF ₃ ; Perfluorocyclobutane, CF ₃ CF ₂ CF ₂ CF ₃ , CF ₃ CF ₂ CF ₂ CF ₂ CF ₃ , it includes _{CF 3 CF 2 CF 2 CF 2} CF 2 CF 3 Pafuruoroaru force down such as and the like, in Naka, PA full O b alkanes are preferred. The use amount of the fluorinated solvent is preferably 10 to 100% by mass with respect to water from the viewpoint of suspendability and economy.

 The polymerization temperature is not particularly limited, and may be 0 to 10 ° C. The polymerization pressure is appropriately determined according to other polymerization conditions such as the type and amount of the solvent used, the vapor pressure, the polymerization temperature, and the like, but may be usually 0 to 9.8-MPaG.

In the polymerization for obtaining the above fluororesin, a usual chain transfer agent, for example, a hydrocarbon such as isopentane, n-pentane, n-hexane and cyclohexane; an alcohol such as methanol and ethanol; Halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride, and methyl chloride can be used. Content of adhesive functional groups such as terminal carbonate groups derived from peroxide Can be controlled by the amount of polymerization initiator such as peroxycarbonate, the amount of chain transfer agent used, the polymerization temperature and other polymerization conditions.

 The powder coating material of the present invention may be composed of the above-mentioned fluororesin and, if necessary, other resins other than the above-mentioned fluororesin. The other resin is not particularly limited as long as it is generally a resin that can be used in powder coatings, and may be either a thermoplastic resin or a thermosetting resin. The above-mentioned other resin is preferably a heat-resistant resin, and more preferably a resin which does not decompose at a heating temperature when coating the above-mentioned fluororesin. Examples of the heat-resistant resin include silicone resin, fluorosilicone resin, polyamide resin, polyamide imide resin, polyimide resin, polyester resin, epoxy resin, polyphenylene sulfide resin, phenol resin, and acrylic resin. And polyether sulfone resins. One or more of the above-mentioned other resins may be used.

 The powder coating may be used by adding an additive or the like as necessary together with the fluororesin. The above additives are not particularly limited as long as they are added to general powder coatings. For example, coloring pigments such as titanium oxide and cobalt oxide for coloring purposes;顔料 Other pigments such as pigments and calcined pigments; carbon fibers, glass fibers, glass flakes, etc., for the purpose of reducing the shrinkage of the coating film and increasing the hardness of the coating film to improve the ease of damage Filler such as my force; For the purpose of imparting conductivity, a conductivity-imparting material such as conductive carbon and the like are included. The additive may be a leveling agent, an antistatic agent, an ultraviolet absorber, a radical scavenger, or the like.

The method for producing the powder coating material of the present invention is not particularly limited, and examples thereof include conventionally known methods such as a pulverizing method, a granulating method, and a spray drying method. Examples of the pulverizing method include a method of pulverizing a raw material comprising the fluororesin and, if necessary, the other resin and the additive using a pulverizer such as a pin mill or an impeller mill. Examples of the granulation method include a method of granulating the raw material using a granulator such as a Henschel mixer or a high-speed mixer. Examples of the spray drying method include a method in which the above raw materials are dispersed in a solvent and atomized into an atmosphere having a temperature equal to or higher than the melting point of the fluororesin to obtain a powder. It is. The method for producing the powder coating may be a method in which the raw materials are mixed in a mixer in advance, then melt-kneaded in a kneader, a melt extruder, or the like, pulverized, and then classified if necessary.

 The particle size of the powder coating is not particularly limited, and is generally preferably small from the viewpoint of adhesion between the obtained coating film and the substrate, but is preferably large for increasing the film thickness. Since the powder coating of the present invention has excellent adhesion between the obtained coating film and the substrate, the particle size of the powder coating may be appropriately determined according to the thickness of the target coating film. However, for example, 10 to: I 00 m is preferable.

 As a coating film forming method for forming a coating film using the powder coating material of the present invention, for example, a method including a step of applying the above powder coating material to a base material and performing a heat treatment is mentioned.

 In the present specification, the “step of applying the powder coating material to the substrate and performing the heat treatment” includes simultaneously or almost simultaneously applying the powder coating material to the substrate and performing the heat treatment. The coating method (P) may be performed, or the coating method (Q) in which the powder coating is applied to a substrate and then subjected to a heat treatment. The above-mentioned coating method (P) includes, for example, a method of performing heat treatment while applying a powder coating to a substrate, such as a rotational molding method; a method of immersing a heated substrate in a powder coating, such as an immersion fluid coating method And the like. Examples of the coating method (Q) include an electrostatic powder coating method.

 In the present specification, the term "applying the powder coating to the base material" means that the powder coating is placed in direct contact with the surface of the base material, and the powder coating is converted from the powder coating. This is a concept that may include placing the film so as to interpose a brayer layer between the obtained coating film and the substrate. In the present specification, the “primer layer” is a coating film obtained by coating a primer on a substrate. The primer is an undercoat paint that is usually used for improving the adhesion between the coating film and the substrate.

The coating film may be in contact with the substrate. Since the powder coating of the present invention uses the above-mentioned fluororesin, even if the coating is in contact with the substrate without the intervention of the primer layer, the adhesion between the substrate and the coating can be improved. Can be made practically sufficient. The powder coating of the present invention has sufficient adhesiveness between the coating and the substrate even when the coating and the substrate are brought into contact with each other without a primer layer interposed therebetween. However, it does not exclude the use of a primer layer to further improve the adhesion between the coating film and the substrate.

 By not interposing the primer layer in the powder coating, the compounds and the like contained in the primer are decomposed and eluted, and the surface smoothness of the coating film obtained by having the primer layer is reduced. In some cases, the surface appearance of the base material such as color and pattern can be utilized in some applications.

 The above-mentioned electrostatic powder coating method is different from a coating method in which a coating film is usually formed continuously on the entire surface of a substrate, such as a rotational molding method and a fluid immersion coating method, and the shape of the substrate is different. This is a coating method that can cause discontinuity in which a surface on which a coating film is formed and a surface on which a coating film is not formed may exist depending on the base material. In a conventional powder coating, there was a risk that the coating would peel off from the discontinuous portion of the coating, but the powder coating of the present invention could form a coating having excellent adhesion to the substrate. Therefore, even with the electrostatic powder coating method, the coating film can be suitably used without peeling off.

 The heat treatment in the coating film forming method is preferably performed at a heating temperature that is equal to or higher than the melting point of the fluororesin and equal to or lower than the decomposition temperature. When the temperature is lower than the melting point of the fluororesin, the adhesiveness between the obtained coating film and the substrate may be insufficient, and when the temperature exceeds the decomposition temperature of the fluororesin, the performance of the fluororesin may be deteriorated. It may be damaged. The heating temperature is preferably 300 ° C. in view of the surface smoothness, foaming and discoloration of the obtained coating film. Since the fluororesin has a low melting point, the powder coating of the present invention can be fired even when the heating temperature is relatively low, for example, 240 ° C. Further, the surface smoothness and adhesion can be improved. A coating film having good strength can be obtained. Since the above-mentioned powder coating can make the heating temperature relatively low, it is possible to widen the selection range of the types of base materials on which the powder coating can be applied.

The above-mentioned heating temperature is preferably 2 in the case where the above-mentioned fluorine resin is a resin made of the above-mentioned tetrafluoroethylene / ethylene copolymer (1) in view of the adhesiveness and surface smoothness of the obtained coating film. Although 80 ° C is a preferable upper limit, from the viewpoint of preventing the decomposition of the adhesive functional group, 220 ° C is a preferable upper limit, and further, it has sufficient performance even at 200 ° C. A coating can be obtained. The heating temperature is set at 300 when the above-mentioned fluororesin is a resin made of the above-mentioned tetrafluoroethylene / ethylene copolymer (2) in terms of adhesion and surface smoothness of the obtained coating film. ° C is a preferred upper limit, but from the viewpoint of preventing the decomposition of the adhesive functional group, 240 ° C is a preferred upper limit.

 The time for performing the heat treatment varies depending on the type of the fluororesin, the thickness of the coating film, and the like.However, when a coating film having a thickness of about 30 to 150 μπι is obtained, the time is 15 to 60 minutes. The preferred upper limit is 30 minutes.

 The heating temperature and the time for performing the heating treatment are as follows: in view of the surface smoothness of the obtained coating film, when the fluororesin is a resin comprising the tetrafluoroethylene-ethylene copolymer (1), It is preferably 15 to 30 minutes at 260 to 280 ° C. However, when heat treatment is performed at 220 to 240 ° C in consideration of the heat resistance of the substrate, 30 to 6 minutes is preferable. 0 minutes is preferred.

The heating temperature and the time for performing the heat treatment are as follows: in view of the surface smoothness of the obtained coating film, when the fluororesin is a resin comprising the tetrafluoroethylene / ethylene copolymer (2), It is preferably 15 to 30 minutes at 260 to 300 ° C, but when heat treatment is performed at 220 to 240 ° C in consideration of the heat resistance of the base material, 30 to 6 minutes. 0 minutes is preferred.

 The method for forming a coating film of the present invention is for forming a coating film using the above powder coating material. Preferably, the method includes a step of performing a heat treatment at a heating temperature of C or lower. Since the powder coating has a low melting point, the heating temperature can be relatively low in accordance with the heat resistant temperature of the base material. For example, even at 200 ° C., the adhesive strength and the surface smoothness can be improved. A coating film having good properties can be obtained.

 The substrate on which the powder coating material of the present invention is applied is not particularly limited as long as it has heat resistance at the above-mentioned heating temperature, and examples thereof include those made of an organic material, an inorganic material, a metal material, and the like.

Examples of the organic material include a heat-resistant material such as a thermoplastic resin, a thermosetting resin, and a synthetic rubber. The powder coating of the present invention has a low melting point and can be heated at a low temperature. A wide variety of organic materials that can be used as the substrate can be selected. The organic material may be a single type or a composite of two or more types.

 Examples of the thermoplastic resin include other fluororesins than the above fluororesin, polyacetal resins such as polyphenylene oxide resin [PPO], polyester resins, polyamide resins, polyamide resins, polyamide resins, polyamides Imide resin, polycarbonate resin, acrylic resin, styrene resin, Atari mouth-tolyl / butadiene Z styrene resin [ABS], butyl chloride resin, ethylen butyl alcohol resin, cellulose resin, butyl acetate resin, polyether And polyether sulfone resin [PEES], polyether sulfone resin [PES], polyether imido resin, polybutyl alcohol resin, polyphenylene sulfide resin, and modified polyolefin resin. Examples of the modified polyolefin resin include an epoxy-modified polyolefin resin.

Examples of the thermosetting resin include an amino resin, an epoxy resin, an unsaturated polyester resin, a phenol resin, a urethane resin, and a silicone resin. Examples of the synthetic rubber include nitrile / butadiene rubber, isoprene rubber,

Examples include chloroprene / acrylic rubber, ethylene / propylene rubber, urethane rubber, silicone rubber, fluorine rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, polysulfide rubber, and chlorinated polyethylene rubber.

 The inorganic material is not particularly limited. For example, quartz; glass-based materials such as crystallized glass, foamed glass, heat-reflective glass, heat-absorbing glass, and double-layer glass; ceramic-based substrates such as tiles, ceramics, and bricks Natural stone; concrete base or cement base; silicon such as monocrystalline silicon, polycrystalline silicon, amorphous silicon, and the like.

Examples of the above metal materials include metals such as aluminum, iron, nickel, titanium, molybdenum, magnesium, manganese, copper, silver, lead, chromium, beryllium, tungsten, and cobalt, and compounds of these metals. From two or more Alloys and the like.

 For the purpose of preventing corrosion, etc., the base material made of the above-mentioned metal material is coated with another metal by electric plating, melting plating, chromizing, siliconizing, calorizing, sheradizing, thermal spraying, etc. A phosphate film formed by an acid treatment, a metal oxide formed by anodic oxidation or thermal oxidation, electrochemical corrosion treatment, or the like may be used.

 The above base material has been subjected to a surface roughening treatment such as sandplast, shotplast, grid blast, honing, paper scratch, wire scratch, hair line treatment, etc. for the purpose of improving the adhesion to the coating film. There may be.

 Even if the substrate has a surface roughness (R a) of 0.1 x m or less, the powder coating of the present invention can be suitably used. In the present specification, the surface roughness (R a) is a value obtained by measuring the surface roughness (R a) described later. Examples of the substrate having a surface roughness (R a) within the above range include those not subjected to the above-described surface roughening treatment. Since the powder coating of the present invention uses the fluororesin, the adhesion between the substrate and the obtained coating film can be practically sufficient without subjecting the substrate to a surface roughening treatment. However, it is not excluded that the substrate is subjected to a surface roughening treatment in order to further improve the adhesion between the coating film and the substrate.

Conventional powder coatings have been used in which a filler such as carbon fiber is added to a fluororesin other than the above-mentioned fluororesin in order to improve the surface hardness and the like of the obtained coating film. The above-mentioned conventional powder coating may have a good adhesion to the base material and may give a coating film which is difficult to peel off by adding a filler. It is presumed that the shrinkage when heated to a temperature equal to or higher than the melting point of the other fluororesin and then cooled to room temperature was unintentionally suppressed. However, in the conventional powder coatings described above, the coating film obtained by adding the filler may be colored or have poor transparency, and depending on the application, the appearance of the base material such as color and pattern cannot be utilized. There was a problem. The powder coating of the present invention has an advantage that a coating film having excellent adhesion to a substrate can be obtained without adding the above filler. 2004/000146

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Powder coatings such as have not been previously obtained. The powder coating of the present invention has an advantage that a coating film having excellent adhesion to a substrate can be obtained without adding a filler, but as described above, the shrinkage of the coating film is low. This does not preclude the addition of buoyers to the tl for additional reduction.

 In the method for forming a coating film according to the present invention, the coating film is obtained from the above powder coating. Since the above-mentioned coating film is obtained from the above-mentioned powder coating material, it has good adhesiveness to the substrate and surface smoothness, and also has the heat resistance, corrosion resistance, and chemical resistance inherent to the above-mentioned fluororesin. It has properties such as non-adhesiveness.

 According to the coating film forming method of the present invention, a laminated structure composed of the base material and the coating film can be obtained. The laminated structure may be one in which the above-described primer layer is interposed between the above-mentioned base material and the above-mentioned coating film.However, since the powder coating of the present invention is used, the above-mentioned primer layer is not interposed. The base material and the coating film may be in contact with each other.

 The laminate of the present invention comprises a substrate, and a coating film obtained by applying the powder coating on the substrate and performing a heat treatment. This laminate has a laminate structure in which the base material and the coating film are in contact with each other without the above-described primer layer interposed therebetween. Since the laminate has a coating film obtained from the powder coating, as described above, even if the coating film is in contact with the base material, the adhesion between the coating film and the base material is improved. It can be sufficient for practical use. Examples of the substrate include those similar to those described above for the substrate.

 The laminate may have the base material, the coating film, and another layer on the coating film. The other layer is not particularly limited, and includes, for example, a layer made of an organic material, an inorganic material, a metal material, or the like, and may use one or more of these.

Examples of applications of the above-mentioned laminated structure and the laminate of the present invention include a coating for protecting a substrate from erosion of a chemical solution and the like, and a coating for imparting non-adhesiveness to the surface of the substrate. The coating for protecting the base material from erosion by a chemical solution or the like is not particularly limited. For example, semiconductor manufacturing equipment such as a valve, a tank, a diaphragm, a wafer carrier, a wafer mounting table, etc. Piping for hoses, joints, etc. 4 000146

twenty one

Materials; Chemistry 'Medical instruments; Pipes, valves, fittings, pumps, tanks, and other corrosion-resistant linings. The above-mentioned semiconductor manufacturing device · The component for a semiconductor manufacturing device is a component constituting the semiconductor manufacturing device and / or the semiconductor manufacturing device. The piping material may be used as the semiconductor manufacturing device / part for a semiconductor manufacturing device. Examples of the chemical include a highly corrosive chemical such as hydrofluoric acid.

 The coating for imparting non-adhesion to the surface of the base material is not particularly limited, and examples thereof include a gas table, a range hood, a ventilation fan body, a ventilation fan fan, a kitchen wall material, an oven inner wall, an oven body, and an oven toaster inner wall. And body, microwave oven body and inner wall, frying pan, hot plate, rice cooker inner pot, cake mold, pole, home bakery supplies, bread mold, pot, rice cake sticker, gas water heater body, water purifier body, dish dryer Interior and exterior of jars, inner jars and pots, tabletop cooking pots, kitchen knives, pickling tubs and other kitchen-related products; iron, illuminator umbrella and exterior, washing machine interior and exterior, clothes dryer interior and exterior, Fan for fan, outdoor unit for air conditioner, interior and exterior for hot air heater and fan, audio panel Electronic components such as printed circuit boards; Office automation [OA] Sliding materials such as equipment doors and belts for OA equipment; Blinds, partitions, steel Furniture, ornaments, sanitary interiors, toiletry interiors, etc. Interior products; exterior wall materials, roofing materials, fences, gates, postal posts, rain gutters, tents, shutters, guardrails, road signs, ship interiors, outdoor advertising, clothes poles, water tanks, fuel tanks, vehicles, monuments, objects And other outdoor products. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Synthesis Example 1 Synthesis of fluororesin (A)

After pouring pure water (380 L) into the 1000 L autoclave and sufficiently purging with nitrogen, 1-fuzoreo-1,1-dichloroethane 80 kg, hexafenole propylene 170 kg, Perphnoleo mouth (1, 1, 5 _ tri-hydridone 11-pentene) 0. 5 kg was charged, and the inside of the system was kept at 35 ° C and the stirring speed was 200 rpm. After that, tetrafluoroethylene was injected to 0.9 MPa, ethylene was further injected to 1.0 MPa, and then 8.0 kg of di-n-propylperoxydicarbonate was added to initiate polymerization. Started. Since the pressure in the system decreases with the progress of polymerization, a mixed gas of tetrahenoleoethylene: ethylene: hexaph / leopropylene = 40: 44: 16 mol ° / ₀ is continuously supplied to reduce the system pressure to 1. OMP a kept. A total of 4.4 kg of perfluoro (1, 1, 5-trihydro-one pentene) was also continuously charged, and stirring was continued for 30 hours. After the pressure was released to atmospheric pressure, the reaction product was washed with water and dried to obtain 200 kg of a powder of fluororesin (A). The composition of the fluororesin (A) measured by ¹⁹ F-NMR analysis was as follows: tetraphnoleo ethylene: ethylene: hexafnoreo propylene: perphnoleo (1,1,5-trihydro-11-pentene) = 41.0: 44. 6: 13.8: 0.6 monole%. Synthesis Example 2 Synthesis of Fluororesin (B)

Fluororesin (B) was obtained in the same manner as in Synthesis Example 1 except that a mixed gas of tetrafluoroethylene: ethylene: hexafenoleopene propylene = 46: 44: 10 mol% was used in Synthesis Example 1. . The composition of the fluororesin (B) measured by ¹⁹ F-NMR analysis was: tetrafluoroethylene: ethylene: hexafluoropropylene: perfluoro (1,1,5-trihydridine-one-one-pentene) = 45 9: 44.1: 9.5: 0.5 mol '%. Synthesis Example 3 Synthesis of Fluororesin (C)

Pour 50 L of pure water into a 100 L autoclave and sufficiently purge with nitrogen, and then add 35 kg of 1-fluoro-1-ol, 1 kg of ethane at the mouth and 10 kg of perfluoromethylvinyl ether. The preparation and the inside of the system were maintained at 35 ° C. and the stirring speed was 200 rpm. Thereafter, tetrafluoroethylene was injected to 0.8 MPa, and then 0.4 kg of di-n-propylperoxydicarbonate was charged to initiate polymerization. As the pressure in the system decreases with the progress of polymerization, tetrafluoroethylene: perfluoromethy . Rubi - ether = 87 5: continuously supplying a mixed gas of 12.5 mol _^0/0, and maintain the system inside pressure at 0. 8MP a. After stirring was continued for 30 hours, the pressure was released to atmospheric pressure, and the reaction product was washed with water and dried to obtain 30 kg of a powder of fluororesin (C). ¹⁹ F- composition of NMR analysis fluorocarbon resin measured by (C) is Tetorafuruoro ethylene: Par Full O b methyl-bi two Noreeteru = 87.3: 1 2.7 mole _^0/0 der ivy. Synthesis Example 4 Synthesis of Fluororesin (D)

400 L of pure water was charged into a 1000 L autoclave, and after sufficiently purging with nitrogen, 270 kg of butane perfluorosiloxane was charged. Next, 200 g of cyclohexane and 950 g of perfluoro (1,1,5-trihydryl 11-pentene) were injected into the system. C, stirring speed was maintained at 250 rpm. Thereafter, while stirring, a mixed gas of tetrafluoroethylene: ethylene = 96: 4 mol% was charged until the internal pressure of the system reached 1.2 MPa. The reaction was started by injecting 600 g of di-n-propyl peroxydicarbonate. Since the pressure in the system decreases as the polymerization proceeds, a mixed gas of tetrafluoroethylene: ethylene = 67: 33 mol% was continuously supplied, and the pressure in the system was kept at 1.2 MPa. Further, 1 90 kg of the Te trough Ruo B Ethylene: Ethylene = 67: For 33 mole _^0/0 mixed gas, per Furuoro (1, 1, 5-trihydrofluorinated-1 one-pentene) is 1 2 kg In this way, perfluoro (1, 1, 5-trihydro-11-pentene) was continuously charged and polymerized. After completion of the polymerization, the pressure was released to atmospheric pressure, and the reaction product was washed with water and dried to obtain 200 kg of a powder of fluororesin (D). The composition of the fluororesin (D) measured by ¹⁹ F-NMR analysis was: tetrafluoroethylene: ethylene: perfluoro (1,1,5-trihydro-11-pentene) = 65.3: 32.7: 2. It was 0% / m%. Preparation example Preparation of powder coating

The powder of the fluororesins (A) to (D) obtained in each of the above synthesis examples was compressed using a roller compactor (manufactured by Matsupo), and then ground while adjusting the particle size. 2004/000146

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Body paints (A) to (D) were obtained.

 Powder coating (E) was obtained by pulverizing while adjusting the particle size using NEOFLON PVDF VP 835 (manufactured by Daikin Industries, Ltd.) as the fluororesin (E).

 The average particle diameter of the obtained powder coating materials (A) to (E) was measured using a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation). Table 1 shows the results.

Evaluation of fluororesin

 Using the obtained powder coatings (A) to (E), the melting points of the fluororesins (A) to (E) and the half width of the melting point at the melting peak were measured by the method described above, and the following method was used. The melt flow rate was measured. Table 1 shows the results.

(Melt flow rate)

 Using a melt indexer (manufactured by Toyo Seiki Seisaku-sho), at 265 ° C and 5 kg load for fluororesins (A) to (D), and at 230 ° C and 10 kg for fluororesin (E) Under load, the mass (g) of the polymer flowing out from a nozzle 2 mm in diameter and 8 mm in length per unit time (10 minutes) was measured. table 1

Examples 1 to 7 and Comparative Examples 1 to 2

S US base material (10 OmmX 5 OmmX lmm, surface roughness (Ra) = about 0.03 zm) and alumina emery (# 80Z # 100 = iZl) were used for surface roughness (Ra) = Blast processing was performed so as to be 1-2 / xm. On the blasted substrate, apply the powder coatings shown in Table 2 to a film thickness of approximately 80 Xm. 4000146

twenty five

It was applied by an electrostatic powder coating method so as to be as it was. Thereafter, heating was performed under the conditions shown in Table 2 to obtain a coating film. Evaluation of coating film

 The surface roughness (Ra) and adhesive strength of the obtained coating film were measured by the following methods. Table 2 shows the results.

 (Surface roughness (Ra))

 The surface roughness (Ra) was measured using a surface roughness measuring device (manufactured by Mitutoyo Corporation) in accordance with JIS B0601.

 (Adhesive strength)

 In order to prevent the coating film from breaking when measuring the adhesive strength, the powder coating (A) was placed on the obtained coating film so that the film thickness after heat treatment became lnim. Thereafter, the specimen was heated at 220 ° C. for 1 hour to obtain a test piece. A cut was made to a width of 2 cm on the coating film of the obtained test piece, the coating film edge was partially peeled off, and the peel strength was measured from the maximum point using a Tensilon universal tensile tester (manufactured by A & D Corporation). Was measured. For the powder coatings (A) to (E), the shrinkage was measured by the following method. Table 2 shows the results.

 (Shrinkage factor)

 A release agent (Daifree, manufactured by Daikin Industries, Ltd.) is applied to the surface of a SUS substrate that has not been subjected to plast treatment, and the powder coating (A) to (A) is applied so that the film thickness after heat treatment is 150 / im. E) was electrostatically painted on a 3 cm long X 3 cm wide section. Thereafter, a heat treatment was performed under the conditions shown in Table 2 to obtain a coating film. The resulting coating film was immersed together with the substrate in hot water at about 98 ° C. for about 12 hours, whereby the coating film was peeled off from the substrate without applying external force to obtain a coating film for measurement. The length and length of the obtained coating film for measurement were measured, and averaged to calculate the shrinkage.

Table 2 shows the results. Examples 8 to 9 and Comparative Example 3 A coating film was obtained using each of the powder coatings shown in Table ² in the same manner as in Example 1, except that the sus base material was not subjected to the blast treatment. For each of the above items, the results are shown in Table 2 below.

 ) (% /) () () Min N m c m

Table 2

 Example 1

 Example 2

 σ>

 Example 3 1 1 1

 〇 o o o o o

 Example 4

 Example 5 dimensions o Example 7 dimensions o

 <o o o

 o¾ σ>

 -i! — 1

 Example 9

 Comparative ratio 1

 Comparative ratio 2

 a

 Dimension to Comparative Example 3

 «\ CO σ LO o

 Glowing o o

 oo

Dimension CD o Dimension CO CM O LO O

 Dimensions 〇 〇 o o <〇 〇

Ο o o o o o O o O O O O o O o o o o o o o O o O

 o oo 00 00 00

 CM

<<<CQ ffl ϋ; m QWQ Each of the coating films of Examples 1 to 7 was superior in adhesion to the coating films of Comparative Examples 1 and 2. The coating films of Examples 2 to 3 and Examples 5 to 6 obtained by heating the powder coating (A) and the powder coating (B) at a heating temperature of 260 to 280 ° C. The surface smoothness was also excellent. The coating films of Examples 8 to 9 had good adhesiveness without blasting the substrate. Industrial applicability

 Since the powder coating of the present invention has the above-described configuration, the obtained coating film can have good adhesion to the substrate and surface smoothness without using a primer or performing a surface roughening treatment on the substrate. It is excellent.

Claims

The scope of the claims

1. a powder coating made of fluororesin,

The fluororesin has a melting point of 150 ° C. to 260 ° C. and a half-value width of a melting point at a melting peak of 30 ° C. or more.

A powder coating characterized by the following.

2. A powder coating made of fluorine resin,

The shrinkage of the coating film for measurement obtained from the fluororesin is 2% or less.

A powder coating characterized by the following.

3. The powder coating according to claim 2, wherein the shrinkage is 1% or less.

4. The fluororesin is a resin comprising a tetrafluoroethylene unit and a tetrafluoroethylene Z-ethylene copolymer having ethylene units.

Powder coating according to item 2 or 3.

5. The tetrafluoroethylene / ethylene copolymer has the following general formula (I) CX = CY ¹ — R ί ¹ -Ζ ¹ (I)

(Wherein, X ^1, ¥ ¹ and 2 ¹ are the same or different, represent a hydrogen atom or fluorine atom, R f ¹ is an alkylene group of 0 to 4 carbon atoms, containing 1 to 4 carbon atoms 0 And a fluorine-containing alkylene group having 1 to 40 carbon atoms having an ether bond or a fluorine-containing oxyalkylene group having 1 to 40 carbon atoms having an ether bond. 5. The powder coating according to claim 4, wherein the powder coating has a monomer (a) unit derived from the monomer (a).

6. tetrafluoropropoxy O b / ethylene copolymer, tetrafurfuryl O b ethylene unit 3 5-8 1 mole _^0/0, ethylene unit 6-5 0 mole _^0/0, and, in the monomer (a) Claim 5 wherein the monomer (a) is derived from 5 to 59 mol%. On the powder coating.

7. The powder coating according to claim 5, wherein the monomer (a) is composed of hexafluoropropylene.

8. Fluororesin has tetrafluoroethylene units and the following general formula (II) CF ₂ = CF-R f ² (II)

(In the formula, R f ² is a perfluoroalkyl group having 1 to 40 carbon atoms, a perfluorooxyalkyl group having 1 to 40 carbon atoms, a perfluoroalkyl group having 1 to 40 carbon atoms having an ether bond. Represents a monofluoroalkyloxy group having 1 to 40 carbon atoms having an ether bond or a group having a unit (a 1) derived from the monomer (a 1) represented by 4. The powder paint according to claim 1, 2 or 3, which is a resin.

9. The powder coating according to claim 8, wherein the monomer (a1) is composed of hexafluoropropylene.

10. The powder coating according to claim 8, wherein the monomer (al) is composed of perfluoro (alkyl butyl ether).

1 1. The powder coating according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, wherein the fluororesin has an adhesive functional group.

1 2. A coating film for forming a coating film by using the powder coating described in claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 A forming method, comprising a step of applying the powder coating material to a base material and performing a heat treatment at a heating temperature that is equal to or higher than the melting point of the fluororesin.

A method for forming a coating film, comprising:

13. The method for forming a coating film according to claim 12, wherein the coating film is in contact with the substrate.

14. The coating film forming method according to claim 12, wherein the substrate has a surface roughness (R a) of 0.1 m or less.

15. Substrate and Claims 1, 2, 3, 4, 5, 6, 7, 8,

A coating film obtained by applying the powder coating according to 9, 10, or 11 and subjecting it to heat treatment

A laminate characterized by the above. '

16. The laminate according to claim 15, wherein the substrate has a surface roughness (Ra) of 0.1 / zm or less.