JP2009263609A - Powder coating material and primer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder coating material and a primer from which a coating film having excellent resistance to thermal adhesion can be obtained. <P>SOLUTION: The powder coating material or the primer includes a chlorotrifluoroethylene copolymer. The chlorotrifluoroethylene copolymer is composed of a chlorotrifluoroethylene unit, a tetrafluoroethylene unit and a monomer [A] unit derived from a monomer [A] copolymerizable with chlorotrifluoroethylene and tetrafluoroethylene. The chlorotrifluoroethylene unit and the tetrafluoroethylene unit account for 90-99.9 mol% in total. The monomer [A] unit accounts for 0.1-10 mol%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a powder coating material and a primer.

Since chemical / medical instruments, piping materials for semiconductor manufacturing equipment, etc. usually come into contact with chemicals during use, it is desirable to have resistance to chemicals. A fluororesin is suitable for these applications because it is excellent in heat resistance, corrosion resistance, non-adhesiveness, and lubricity. As a method of using the fluororesin, for example, it is contained in a paint, applied to a substrate to obtain a coating film, dried as necessary, and then fired to form a coating film containing the fluororesin. There are methods.

Fluorine resin is generally excellent in heat resistance, but even if it has a certain degree of adhesion immediately after application as a paint, under severe conditions such as hot water or high temperature, There has been a problem that the adhesiveness is lowered, and a coating film defect such as a crack in the coating film or peeling of the coating film from an object to be coated may occur.

In order to solve this problem, the primer layer is composed of ETFE (A) and a binder component, the surface layer is composed of ETFE (B), and the fluorine content of ETFE (B) is ETFE. An ETFE lining member having a fluorine content greater than or equal to (A) has been proposed (for example, see Patent Document 1). Further, a fluorine-containing coating composition obtained by blending a polymer material and a meltable fluororesin having an average particle size of 0.1 to 30 μm, wherein the volume ratio of the meltable fluororesin and the polymer material Has proposed a fluorine-containing coating composition in which the meltable fluororesin: the polymer material is 35:65 to 95: 5 (see, for example, Patent Document 2).

International Publication No. 03/068499 Pamphlet International Publication No. 02/090450 Pamphlet

An object of the present invention is to provide a powder coating material and a primer capable of obtaining a film having low water permeability and further excellent heat-resistant adhesion, in view of the above-described present situation.

The present invention is a powder coating material containing a chlorotrifluoroethylene copolymer, the chlorotrifluoroethylene copolymer comprising a chlorotrifluoroethylene unit, a tetrafluoroethylene unit, and chlorotrifluoroethylene and tetra It is composed of monomer [A] units derived from monomer [A] copolymerizable with fluoroethylene, and the chlorotrifluoroethylene units and tetrafluoroethylene units are 90 to 99.9 mol% in total. And the monomer [A] unit is 0.1 to 10 mol%.

The present invention is a fluororesin film formed from the above powder paint.

The present invention is an article characterized by having a base material, a primer film formed on the base material, and a fluororesin film formed from the powder paint on the primer film.

The present invention is a primer containing a chlorotrifluoroethylene copolymer, a heat resistant resin and a dispersion medium, the chlorotrifluoroethylene copolymer comprising a chlorotrifluoroethylene unit, a tetrafluoroethylene unit, and a chlorotrifluoroethylene unit. It is composed of monomer [A] units derived from monomer [A] copolymerizable with trifluoroethylene and tetrafluoroethylene, and the chlorotrifluoroethylene units and tetrafluoroethylene units are 90 to 99.9 mol%, the monomer [A] unit is 0.1 to 10 mol%, and the solid content ratio of the chlorotrifluoroethylene copolymer and the heat-resistant resin is based on mass. It is a primer characterized by being 40: 60-90: 10.

The present invention is a primer film formed from the above primer.

The present invention is an article comprising a substrate, a primer film formed from the primer on the substrate, and a fluororesin film formed on the primer film.

The present invention is an article comprising a substrate, a primer film formed from the primer on the substrate, and a fluororesin film formed from the powder paint on the primer film.

The present invention is described in detail below.

The powder coating material and primer of the present invention are characterized by containing a chlorotrifluoroethylene copolymer, whereby a film showing excellent heat-resistant adhesion can be obtained.

The chlorotrifluoroethylene copolymer (hereinafter referred to as “CTFE copolymer”) includes chlorotrifluoroethylene units [CTFE units], tetrafluoroethylene units [TFE units], and chlorotrifluoroethylene [CTFE]. And a monomer [A] unit derived from a monomer [A] copolymerizable with tetrafluoroethylene [TFE].

In the present specification, the “CTFE unit” and the “TFE unit” are derived from chlorotrifluoroethylene moiety [—CFCl—CF ₂ —] and tetrafluoroethylene, respectively, in the molecular structure of the CTFE copolymer. parts [-CF 2 _-CF 2 _-] is, each "monomer (a) unit", similarly, the molecular structure of the CTFE copolymer, the portion monomer (a) is added It is.

The monomer [A] is not particularly limited as long as it is a monomer copolymerizable with CTFE and TFE, and may be two or more as long as it is at least one, but ethylene [Et ], Vinylidene fluoride [VdF], perfluoro (alkyl vinyl ether) [PAVE], the following general formula (I)
CX ³ X ⁴ = CX ¹ (CF ₂ ) _n X ² (I)
(Wherein X ¹ , X ³ and X ⁴ are the same or different and represent a hydrogen atom or a fluorine atom, X ² represents a hydrogen atom, a fluorine atom or a chlorine atom, and n is an integer of 1 to 10) And a vinyl monomer represented by the following general formula (III)
_{CF 2 = CF-OCH 2 -Rf} (III)
And alkyl perfluorovinyl ether derivatives represented by the formula (wherein Rf is a C 1-5 perfluoroalkyl group).

The monomer [A] is preferably at least one selected from the group consisting of Et, VdF, PAVE and the vinyl monomer represented by the general formula (I).

The monomer [A] is a PAVE, a vinyl monomer represented by the general formula (I), and / or an alkyl perfluorovinyl ether derivative represented by the general formula (III), respectively. One kind or a combination of two or more kinds can be used.

Although it does not specifically limit as a vinyl monomer represented by the said general formula (I), For example, hexafluoropropylene [HFP], perfluoro (1,1,2- trihydro-1-hexene), perfluoro ( 1,1,5-trihydro-1-pentene), the following general formula (IV)
H ₂ C = CX ⁵ Rf ⁵ (IV)
(Wherein, X ⁵ is H, F, or CF ₃ , and Rf ⁵ is a perfluoroalkyl group having 1 to 10 carbon atoms).

As the perfluoro (alkyl) ethylene, perfluoro (butyl) ethylene is preferable.

As the alkyl perfluorovinyl ether derivative represented by the general formula (III), those in which Rf is a perfluoroalkyl group having 1 to 3 carbon atoms are preferable, and CF ₂ = CF—OCH ₂ —CF ₂ CF ₃ is more preferable. preferable.

As the PAVE, the following general formula (II)
^{_{CF 2 = CF-ORf 1 (}} II)
(Wherein Rf ¹ represents a perfluoroalkyl group having 1 to 8 carbon atoms) and is more preferably perfluoro (alkyl vinyl ether). Examples of the perfluoro (alkyl vinyl ether) represented by the general formula (II) include perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), perfluoro (propyl vinyl ether), and perfluoro (butyl vinyl ether). Among them, perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), or perfluoro (propyl vinyl ether) is preferable.

Conventionally, CTFE and vinyl ether tended to be inferior in copolymerizability. However, the CTFE copolymer described above has a relatively high copolymerization ratio of PAVE and / or fluorine-free vinyl ether by copolymerizing TFE as well. It is possible to copolymerize.

As said monomer [A], you may use unsaturated carboxylic acid copolymerizable with CTFE and TFE.

The unsaturated carboxylic acids are not particularly limited, and examples thereof include unsaturated aliphatic carboxylic acids having 3 to 6 carbon atoms, and may be unsaturated aliphatic polycarboxylic acids having 3 to 6 carbon atoms.

The unsaturated aliphatic polycarboxylic acids are not particularly limited, and examples thereof include maleic acid, itaconic acid, citraconic acid, and acid anhydrides thereof.

Two or more monomers [A] may be used, but when one of them is VdF, PAVE and / or HFP, it is not used in combination with itaconic acid, citraconic acid and acid anhydrides thereof. May be.

The CTFE copolymer is obtained by using TFE as an essential monomer, and further adding the monomer [A] at a specific ratio described later, whereby heat resistance, moldability, Stress cracking and chemical resistance can be improved.

The CTFE copolymer is not only known as a characteristic of polychlorotrifluoroethylene [PCTFE], but also a liquid such as a chemical solution that has not been known as a property of PCTFE. It also has low permeability.

In the CTFE copolymer, the monomer [A] unit is 0.1 to 10 mol%, and the CTFE unit and the TFE unit are 90 to 99.9 mol% in total. If the monomer [A] unit is less than 0.1 mol%, it tends to be inferior in moldability, environmental stress crack resistance and stress crack resistance, and if it exceeds 10 mol%, it has low chemical solution permeability and heat resistance. , Tend to be inferior in mechanical properties and productivity.

When the monomer [A] is PAVE, the more preferable lower limit of the monomer [A] unit is 0.5 mol%, the more preferable upper limit is 5 mol%, and the more preferable upper limit is 3 mol%. It is.

The ratio of the monomer [A] unit in the CTFE copolymer is a value obtained by analysis such as ¹⁹ F-NMR, specifically, NMR analysis, infrared spectrophotometer [IR], element This value is obtained by appropriately combining analysis and fluorescent X-ray analysis depending on the type of monomer.

The CTFE unit is preferably 10 to 90 mol% of the total of the CTFE unit and the TFE unit. When the CTFE unit in the total of the CTFE unit and the TFE unit is less than 10 mol%, the chemical solution low permeability may be insufficient, and when it exceeds 90 mol%, the polymerization rate rapidly decreases. Not only is productivity lowered, chemical resistance may be lowered, or heat resistance may be insufficient. A more preferred lower limit is 15 mol%, a still more preferred lower limit is 20 mol%, a more preferred upper limit is 80 mol%, a still more preferred upper limit is 70 mol%, and a particularly preferred upper limit is 55 mol%.

When using PAVE as the monomer [A], the CTFE unit can be widely selected with respect to the total of the CTFE unit and the TFE unit, more preferably 15 to 90 mol%, still more preferably It can be 20-90 mol%.

If the polymer chain portion derived from the monomer is composed of the CTFE unit, the TFE unit and the monomer [A] unit, the end of the polymer chain is the CTFE unit or the TFE unit. And the monomer [A] unit may have a different chemical structure. The polymer chain terminal is not particularly limited, and may be, for example, an unstable terminal group described later.

When the CTFE copolymer is melt-molded at a molding temperature of 300 ° C. or higher, the CTFE copolymer preferably has 80 or less unstable terminal groups per 10 ⁶ carbon atoms. When it exceeds 80 per 10 ⁶ carbon atoms, foaming is likely to occur during melt molding at a molding temperature of 300 ° C. or higher. A more preferred upper limit is 40, a still more preferred upper limit is 20, and a particularly preferred upper limit is 6. If the number of unstable terminal groups is within the above range, the lower limit can be set to, for example, one from the viewpoint of measurement limit.

When melt molding at a molding temperature of less than 300 ° C., those having an unstable terminal group number exceeding 80 per 10 ⁶ carbon atoms are preferred. In the case of melt molding at a molding temperature of less than 300 ° C., if the number is 80 or less per 10 ⁶ carbon atoms, the adhesiveness may decrease. A more preferred lower limit is 100, a still more preferred lower limit is 150, a particularly preferred lower limit is 180, and a most preferred lower limit is 220. When melt molding is performed at a molding temperature of less than 300 ° C., the number of unstable terminal groups can be set to 500, for example, from the viewpoint of productivity if the number is within the above range.

The unstable terminal group is usually formed at the end of the main chain by addition of a chain transfer agent or a polymerization initiator used during polymerization, and is derived from the structure of the chain transfer agent or polymerization initiator. is there.

In the present specification, the “labile end group” is —CF ₂ CH ₂ OH, —CONH ₂ , —COF, —COOH, —COOCH ₃ , —CF═CF ₂ , or —CF ₂ H. Examples of the unstable terminal groups, among _{others, -CF 2 CH 2 OH, -CONH} 2, -COF, -COOH, and, -COOCH ₃ adhesiveness, liable affect the foaming at the time of melt molding.

The number of unstable end groups is a value obtained by measurement using an infrared spectrophotometer [IR]. Specifically, the number of the unstable terminal groups is determined by compression molding the CTFE copolymer powder at a molding temperature 50 ° C. higher than the melting point at a molding pressure of 5 MPa. .30 mm film sheet was subjected to infrared absorption spectrum analysis, compared with the infrared absorption spectrum of a known film, the type was determined, and the number calculated from the difference spectrum by the following equation.

Number of end groups (per 10 ⁶ carbon atoms) = (l × K) / t
l: Absorbance K: Correction coefficient t: Film thickness (mm)
Table 1 shows the correction coefficients of the target end groups.

The correction coefficient in Table 1 is a value determined from the infrared absorption spectrum of the model compound in order to calculate the terminal group per 10 ⁶ carbon atoms.

When the CTFE copolymer is melt-molded or heated at a temperature of less than 300 ° C., it preferably has an adhesive functional group. In the present specification, the adhesive functional group is a part of the molecular structure of the polymer contained in the CTFE copolymer and can be involved in the adhesion between the CTFE copolymer and the substrate. means. The adhesion functional functional group is a concept including not only what is 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. is there.

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 carbon divalent group composed of a carbon-oxygen double bond, and is represented by —C (═O) —. The carbonyl group is not particularly limited, and examples thereof include a carbonate group, a halogenoformyl group, a formyl group, a carboxyl group, an ester bond [—C (═O) O—], and an acid anhydride bond [—C (═O) O. -C (= O)-], isocyanate group, amide group, imide group [-C (= O) -NH-C (= O)-], urethane bond [-NH-C (= O) O-], Carbamoyl group [NH ₂ —C (═O) —], carbamoyloxy group [NH ₂ —C (═O) O—], ureido group [NH ₂ —C (═O) —NH—], oxamoyl group [NH ₂ -C (= O) -C (= O)-] and the like which are part of the chemical structure.

The carbonate group is represented by —OC (═O) O—R 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 and an alkyl group having 2 to 20 carbon atoms having an ether bond, and an alkyl group having 1 to 8 carbon atoms and an ether. It is preferably a C2-C4 alkyl group having a bond. Examples of the carbonate group include —OC (═O) OCH ₃ , —OC (═O) OC ₃ H ₇ , —OC (═O) OC ₈ H ₁₇ , —OC (═O) OCH ₂ CH ₂ CH _2. Preferred examples include OCH ₂ CH _{3 and the} like.

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).

A hydrogen atom bonded to a nitrogen atom such as the amide group, imide group, urethane bond, carbamoyl group, carbamoyloxy group, ureido group, or oxamoyl group may be substituted with a hydrocarbon group such as an alkyl group.

The above-mentioned adhesive functional group is easy to introduce and has a suitable heat resistance and good adhesion at a relatively low temperature, so that an amide group, a carbamoyl group, a hydroxyl group, and a carboxyl group can be obtained. Group and carbonate group are preferable, and carbonate group is more preferable.

When the CTFE copolymer has an adhesive functional group, the CTFE copolymer may be composed of a polymer having the adhesive functional functional group at either the main chain end or the side chain. It may consist of a polymer having both chain ends and side chains. When it has an adhesive functional group at the end of the main chain, it may have at both ends of the main chain, or only at one of the ends. The CTFE copolymer has the above-mentioned adhesive functional group at the end of the main chain and / or the side chain, or in place of it, the adhesive functional functional group has a structure generally referred to as a bond such as an ether bond The adhesive functional group may be present in the main chain. The above CTFE copolymer is composed of a polymer having an adhesive functional group at the end of the main chain because it does not significantly reduce mechanical properties and chemical resistance, or is advantageous in terms of productivity and cost. Is preferable.

When the CTFE copolymer is composed of a polymer having an adhesive functional group in the side chain, the adhesive functional functional group-containing monomer can be used in accordance with the target fluorine resin and the fluorine content of the formulation. It can be obtained by copolymerizing with a monomer and / or a fluorine-free monomer. In the present specification, the “adhesive functional group-containing monomer” means a monomer having an adhesive functional group. The above-mentioned adhesive functional group-containing monomer may or may not have a fluorine atom. However, the above-mentioned fluorine-containing monomer and non-fluorine-containing monomer are adhesive functional functional groups. In this respect, it is conceptually distinguished from an adhesive functional functional group-containing monomer having an adhesive functional functional group.

As an adhesive functional group-containing monomer, the following general formula (V)
CX ² ₂ = CY ^2- (Rf ⁴ ) _n -Z ² (V)
(In the formula, Z ² represents a functional group having a hydroxyl group, a carbonyl group or an amino group, X ² and Y ² are the same or different and represent a hydrogen atom or a fluorine atom, and Rf ⁴ has 1 carbon atom. Alkylene group having 1 to 40 carbon atoms, fluorine-containing oxyalkylene group having 1 to 40 carbon atoms, fluorine-containing alkylene group having 1 to 40 carbon atoms having an ether bond, or fluorine-containing oxyalkylene group having 1 to 40 carbon atoms having an ether bond And n represents 0 or 1). 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, an amino group, It means that it may be a functional group having any of these adhesive functional functional groups.

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

The CTFE copolymer is a polymer having an adhesive functional group at the end of the main chain, and when the adhesive functional functional group is a polymer having a carbonate group, polymerization of peroxycarbonate is started. It can obtain by the method of superposing | polymerizing using as an agent. Use of the above method is preferable from the viewpoints of very easy introduction and control of introduction of carbonate groups, quality, such as economical efficiency, heat resistance, and chemical resistance.

As the peroxycarbonate, the following formula

(In the formula, R ⁴ and R ⁵ are the same or different, and are linear or branched monovalent saturated hydrocarbon groups having 1 to 15 carbon atoms, or those having 1 to 15 carbon atoms having an alkoxyl group at the terminal. Represents a linear or branched monovalent saturated hydrocarbon group, and R ⁶ represents a linear or branched divalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a carbon number having an alkoxyl group at the terminal. 1 to 15 linear or branched divalent saturated hydrocarbon groups) are preferred.

Among these, as the peroxycarbonate, diisopropyl peroxycarbonate, di-n-propyl peroxydicarbonate, t-butyl peroxyisopropyl carbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di- 2-ethylhexyl peroxydicarbonate and the like are preferable.

When the CTFE copolymer is a polymer having an adhesive functional group at the end of the main chain, and the adhesive functional functional group is a polymer other than a carbonate group, As in the case of introduction, by using a peroxide such as peroxycarbonate, peroxydicarbonate, peroxyester, and peroxyalcohol as a polymerization initiator, an adhesive functional group derived from the peroxide is obtained. Can be introduced. In addition, “derived from peroxide” is directly introduced from the functional group contained in the peroxide or indirectly by converting the functional group introduced directly from the functional group contained in the peroxide. It means being introduced.

The amount of the polymerization initiator used, such as peroxycarbonate and peroxyester, varies depending on the type and composition of the target fluororesin, the molecular weight, the polymerization conditions, the type of initiator used, etc. It is preferable that it is 0.05-20 mass parts with respect to a part, A especially preferable minimum is 0.1 mass part, and an especially preferable upper limit is 10 mass parts.

The polymerization method for obtaining the CTFE copolymer is not particularly limited, and examples thereof include conventionally known polymerization methods such as solution polymerization, emulsion polymerization, bulk polymerization, and the like, industrially using a fluorine-based solvent, Suspension polymerization in an aqueous medium using peroxycarbonate or the like as the polymerization initiator is preferred.

In the suspension polymerization, a fluorinated solvent can be added to water. Examples of the fluorine-based solvent used for suspension polymerization include hydrochlorofluoroalkanes such as CH ₃ CClF ₂ , CH ₃ CCl ₂ F, CF ₃ CF ₂ CCl ₂ H, and CF ₂ ClCF ₂ CFHCl; CF ₂ ClCFClCF ₂ CF ₃ , chlorofluoroalkanes such as CF ₃ CFClCFClCF ₃ ; perfluorocyclobutane, CF ₃ CF ₂ CF ₂ CF ₃ , CF ₃ CF ₂ CF ₂ CF ₂ CF ₃ , CF ₃ CF ₂ CF ₂ CF ₂ CF ₂ CF _3, etc. Perfluoroalkanes, and the like. Among them, perfluoroalkanes are preferable. The amount of the fluorine-based solvent used is preferably 10 to 100% by mass with respect to water from the viewpoints of suspendability and economy.

It does not specifically limit as polymerization temperature, It may be 0-100 degreeC. The polymerization pressure is appropriately determined according to other polymerization conditions such as the type, amount and vapor pressure of the solvent to be used, the polymerization temperature, etc., but may usually be 0 to 9.8 MPaG.

In the polymerization for obtaining the CTFE copolymer, in order to adjust the molecular weight, usual chain transfer agents, for example, hydrocarbons such as isopentane, n-pentane, n-hexane, and cyclohexane; alcohols such as methanol and ethanol; Halogenated hydrocarbons such as carbon chloride, chloroform, methylene chloride, and methyl chloride can be used. The content of an adhesive functional group such as a carbonate group at the terminal derived from peroxide can be controlled by the polymerization conditions such as the amount of polymerization initiator such as peroxycarbonate, the amount of chain transfer agent used, and the polymerization temperature.

The CTFE copolymer is not particularly limited, and examples thereof include a CTFE / TFE / HFP copolymer, a CTFE / TFE / VdF copolymer, a CTFE / TFE / PAVE copolymer, and a CTFE / TFE / HFP / PAVE copolymer. Examples thereof include a polymer, a CTFE / TFE / VdF / PAVE copolymer, a CTFE / TFE / Et copolymer, and a CTFE / TFE / Et / PAVE copolymer, and a CTFE / TFE / PAVE copolymer is preferable.

The CTFE copolymer may be a polymer constituting either a resin or an elastomer, but preferably constitutes a resin.

As said CTFE copolymer, the thing whose melt flow rate [MFR] is 0.1-70 (g / 10min) is preferable. When the MFR is within the above range, the stress crack resistance is excellent. The more preferable lower limit of the MFR is 1 (g / 10 minutes), and the more preferable upper limit is 50 (g / 10 minutes).

The MFR is a value obtained by measuring the mass of a CTFE copolymer flowing out per 10 minutes from a nozzle having an inner diameter of 2 mm and a length of 8 mm under a 5 kg load at a temperature 70 ° C. higher than the melting point using a melt indexer. .

As said CTFE copolymer, what has melting | fusing point [Tm] 150-300 degreeC is preferable. A more preferred lower limit is 160 ° C, a still more preferred lower limit is 170 ° C, and a more preferred upper limit is 290 ° C.

The melting point [Tm] is a temperature corresponding to a melting peak when the temperature is raised at a rate of 10 ° C./min using a differential scanning calorimeter [DSC].

As said CTFE copolymer, the temperature [Tx] at which 1 mass% of the CTFE copolymer subjected to the heating test decomposes is preferably 370 ° C. or higher. A more preferred lower limit is 380 ° C., and a still more preferred lower limit is 390 ° C. If the said thermal decomposition temperature [Tx] is in the said range, an upper limit can be made into 450 degreeC, for example.

The thermal decomposition temperature [Tx] is obtained by measuring the temperature at which the mass of the CTFE copolymer subjected to the heating test is reduced by 1 mass% using a differential heat / thermogravimetry apparatus [TG-DTA]. Value.

As the CTFE copolymer, the difference [Tx−Tm] between the melting point [Tm] and the temperature [Tx] at which 1% by mass of the CTFE copolymer is decomposed is preferably 150 ° C. or more. If it is lower than 150 ° C., the range in which molding is possible is too narrow, and the range of selection of molding conditions becomes small. Since the CTFE copolymer has a wide moldable temperature range as described above, a high melting point polymer can be used as a counterpart material when coextrusion molding is performed. A more preferable lower limit of the difference [Tx−Tm] is 170 ° C. If the difference [Tx−Tm] is within the above range, the upper limit can be set at 210 ° C., for example, in that the range of selection of molding conditions is sufficiently wide.

The powder coating material of the present invention contains the powder of the CTFE copolymer.

The CTFE copolymer powder has a high density under the condition that a specific gravity of 90% or more of the true specific gravity (specific gravity of the melt-formed product) is obtained by using a roll of the CTFE copolymer powder obtained by the above polymerization method. After pulverization and pulverization, fine particles and fibrous particles in the range of 3 to 40% by mass of the entire particle size distribution of the pulverized product are removed by airflow classification, and further 1 to 20% by mass of the entire particle size distribution of the pulverized product is classified by classification. It is desirable to manufacture by a method of removing particles. Further, it is more desirable to heat-treat at or above the melting start temperature of the fluoropolymer powder after classification of the coarse particles.

First, the CTFE copolymer bulk powder is compressed into a sheet using a roll or the like under a condition that 90% or more, preferably 95 to 99% of the true specific gravity is obtained. When the specific gravity after compression is less than 90% of the true specific gravity, the apparent density of the particles obtained after pulverization is low and the fluidity of the powder is poor. When the specific gravity after compression exceeds 99% of the true specific gravity, the particles obtained after pulverization have a non-uniform shape, and the apparent density is low and the fluidity of the powder becomes poor.

In forming a sheet with a roll, the sheet thickness is set to 0.05 to 5 mm, preferably 0.1 to 3 mm. The roll to be used is preferably one in which two or more rolls are arranged in a vertical type, an inverted L type, a Z type, and the like, and specifically includes a calendar roll, a mixing roll, a roller compactor, and the like. When such a roll is used, a strong shearing force is applied to the CTFE copolymer bulk powder during sheeting, and pores and bubbles present in the bulk powder can be removed to obtain a uniform sheet. It becomes. It is preferable that the sheet is produced under the condition of being milky white or transparent at a temperature of 0 to 250 ° C., preferably 5 to 150 ° C.

In general, the sheet is pulverized by a pulverizer after being pulverized so as to have an average particle diameter of 0.1 to 10 mm by a pulverizer.

Crushing is performed by fixing a screen or a mesh having a hole having a size of a pulverized particle size and crushing it, or by crushing by passing several rolls having grooves or undulations, and averaging. The particle size is preferably 0.1 to 10 mm.

The pulverization is generally performed by a mechanical pulverizer. The mechanical pulverizer includes an impact type such as a cutter mill, a hammer mill, a pin mill, and a jet mill, and a grinding type in which a rotary blade and an outer peripheral stator are pulverized by a shearing force caused by unevenness. As the pulverizer, a high shearing method is preferable from the viewpoint of pulverization efficiency. The grinding temperature is -200 to 100 ° C. In the freeze pulverization, the temperature is usually -200 to -100 ° C, but may be pulverized at room temperature (10 to 30 ° C). Liquid nitrogen is generally used for freeze pulverization, but the equipment is enormous and the pulverization cost is high. It is appropriate to grind at room temperature (10 ° C.) to 100 ° C., preferably at a temperature close to room temperature (10 ° C. to 30 ° C.) in that the process becomes simple and the grinding cost can be suppressed. The obtained powder particles have a uniform particle size distribution rather than a non-uniform form obtained by pulverizing fine particle aggregates or pellets, and the average particle size is 5 to 100 μm.

After removing fine particles and fibrous particles by airflow classification, coarse particles are further removed by classification.

In the airflow classification, the pulverized particles are sent to a cylindrical classification chamber by reduced-pressure air, dispersed by a swirling airflow in the room, and fine particles are classified by centrifugal force. The fine particles are collected from the center to a cyclone and a bag filter and formed into a sheet again. In the classification chamber, a rotating body such as a conical cone or a rotor is installed so that the pulverized particles and the air can perform a swirl motion uniformly.

When using a classification cone, the classification point is adjusted by adjusting the air volume of the secondary air and the gap between the classification cones. When using a rotor, adjust the air volume in the classification chamber according to the number of rotations of the rotor. The blower has a wind pressure of 0.1 to 1 MPa, preferably 0.3 to 0.6 MPa. The classification range is 3 to 40% by mass, preferably 5 to 30% by mass, and 3 to 40% by mass of fine particles and fibrous particles are removed. When the fine particles to be removed are less than 3% by mass, the fluidity of the powder cannot be improved, and the leveling property of the formed film is inferior because the particle size distribution is extremely wide. On the other hand, if the fine particles to be removed exceed 40% by mass, it is not suitable in terms of cost.

Examples of the method for removing coarse particles include air classification using a mesh, vibrating sieve, ultrasonic sieve, and the like, and air classification is preferred. The classification range depending on the particle size is 1 to 20% by mass, preferably 2 to 10% by mass of the entire particle size distribution of the pulverized product, and coarse particles in this range are removed.

Fine particles and fibrous particles recovered in the airflow classification can be formed into a sheet again in the same manner as the raw powder. Moreover, the coarse particles classified by the airflow classification using a mesh or the vibrating sieve can be returned to the pulverizer and recycled.

When the classified powder is momentarily brought into contact with an air flow above the melting start temperature of the fluoropolymer powder using a continuous air flow heating dryer, the powder particle surface becomes rounded, the apparent density and powder The fluidity of the coating can be further improved, and a preferable coating powder can be obtained.

The contact temperature of continuous air flow type heat drying is 1000 ° C. or less, preferably 200 to 800 ° C., and the contact time is 0.1 to 10 seconds. As the heat source, gas heating is preferable in terms of energy saving. The heat-treated powder can be further removed by classifying coarse particles by an air flow type sieve or a vibrating sieve to obtain a powder having a narrow particle size distribution.

The powder thus obtained can be coated with an ultrathin film having a thickness of 5 to 30 μm. In order to obtain an ultra-thin film having excellent leveling properties, it is required that the powder has a well-shaped shape, that the apparent density is high, that the powder has excellent fluidity, and that it is easily meltable. The average particle size of the powder is 5 to 30 μm, preferably 10 to 25 μm. When the above conditions are not satisfied, pinholes may be generated in the film, or the surface may become dark skin.

The powder coating material preferably has an average particle size of powder particles of 10 to 1000 μm. When the thickness is less than 10 μm, electrostatic coating tends to be difficult, and when it exceeds 1000 μm, the smoothness when used in rotrining tends to deteriorate. The average particle diameter of the above powder particles is determined by the purpose, and generally 20 to 40 μm is preferable in the case of a thin coating powder coating having a dry film thickness of 100 μm or less. In the case of a thick coating powder coating 40 to 80 μm is preferable, and in the case of a powder coating for lotioning, 200 to 500 μm is preferable.

The powder coating material of this invention may contain other resins other than the said CTFE copolymer as needed. The other resins are not particularly limited as long as they can be used for powder coatings, and may be either thermoplastic resins or thermosetting resins. The other resin is preferably a heat-resistant resin, and more preferably a resin that does not decompose at the heating temperature when the CTFE copolymer is applied. Examples of the heat resistant resin include silicone resin, fluorosilicone resin, polyamide resin, polyamideimide resin, polyimide resin, polyester resin, epoxy resin, polyphenylene sulfide resin, phenol resin, acrylic resin, and polyethersulfone resin. . One or more of the other resins may be used.

The powder coating material of this invention may contain an additive etc. with the said CTFE copolymer as needed. The additive is not particularly limited as long as it is added to a general powder coating material. For example, for the purpose of coloring, coloring pigments such as titanium oxide and cobalt oxide; Other pigments such as pigments and calcined pigments; for the purpose of reducing the shrinkage rate of the film, and for improving the hardness of the film and improving the scratch resistance, such as carbon fiber, glass fiber, glass flake, mica, etc. Filler; For the purpose of imparting conductivity, a conductivity imparting material such as conductive carbon may be used. The additive may also be a leveling agent, antistatic agent, ultraviolet absorber, radical scavenger and the like.

The present invention is also a fluororesin film formed from the powder paint of the present invention. Since the fluororesin film of the present invention is formed from the powder paint of the present invention, it exhibits extremely excellent heat-resistant adhesion. The heat-resistant adhesion can be evaluated by the degree of blistering. Moreover, the fluororesin film of the present invention has a low water permeability. The fact that blisters do not easily occur indicates not only that the heat-resistant adhesion is excellent, but also that water that causes blistering hardly enters the fluororesin film.

This invention is also an article | item characterized by having a base material, the primer film | membrane formed on the said base material, and the fluororesin film | membrane formed from the powder coating material of this invention.

The base material is made of metal or ceramic.

The metal is not particularly limited, and examples thereof include iron; stainless steel such as SUS304, SUS316L, and SUS403; aluminum; plated steel plate that has been subjected to zinc plating, aluminum plating, and the like. The ceramic is not particularly limited as long as it has heat resistance, and examples thereof include ceramics, porcelain, alumina material, zirconia material, and silicon oxide material.

The base material is not particularly limited as long as it is generally desired to form a lining with a fluororesin. For example, a base material that is desired to impart corrosion resistance is suitable. Such substrates include, for example, tanks, vessels, towers, valves, pumps, fittings, other piping materials and other anticorrosive linings; chemical / medical instruments, wafer baskets, coil bobbin tower packing, chemicals And other anticorrosive materials such as valves and pump impellers.

The base material may be subjected to cleaning, roughening, or the like as pretreatment as necessary. It is preferable that the base material is subjected to the pretreatment from the viewpoint of improving the adhesion with the primer film and preventing the deterioration of the fluororesin film. The pretreatment includes, for example, removal of oil from the base material by solvent, cleaning agent, baking off, etc .; chemical etching using hydrochloric acid, sulfuric acid, alkali, etc .; blasting treatment using silica sand, alumina powder, etc. For example, the removal of oxides on the surface of the substrate by means of the above, the provision of irregularities for increasing the surface area, and the like. Further, after blasting, it is possible to coat a material such as ceramic by thermal spraying and to coat a primer thereon.

The article of the present invention is formed by applying a primer on the substrate and drying to form a primer film. After applying the powder coating of the present invention on the primer film, the article is dried and then fired as necessary. Can be manufactured by forming the fluororesin film.

Although it does not specifically limit as said primer, The primer of this invention mentioned later is preferable. When the primer of the present invention described later is used, a primer film composed of a binder component and a CTFE copolymer is laminated between the fluororesin film and the base material. The adhesion between the primer film and the primer film is excellent, and the interlayer adhesion between the primer film and the fluororesin film is excellent due to the compatibility between the CTFE copolymers.

The method for applying the primer to the substrate is not particularly limited. For example, when the primer is in a liquid state, conventionally known methods such as spray coating, dip coating (dipping), electrostatic coating, and the like can be used. The coating can be performed such that the film thickness after drying is preferably 5 to 200 μm, the more preferable lower limit is 10 μm, the more preferable upper limit is 100 μm, and the further preferable upper limit is 50 μm.

Drying after the primer application is performed at 80 to 200 ° C. for 10 to 60 minutes, for example. The drying may be performed at room temperature in advance before heating, thereby relaxing the heating conditions. Alternatively, the top coat may be applied without drying the primer.

The method for applying the powder coating material of the present invention is not particularly limited, and examples thereof include spraying, electrostatic spraying, electrostatic spray coating, fluidized immersion coating, electrostatic fluidized immersion coating, and a rotational training method.

The firing is not particularly limited as long as it is a temperature that exceeds the melting point, softening point, or glass transition point of the fluororesin, and does not cause decomposition of the fluororesin and the binder component and the heat stabilizer that is optionally blended. Usually, it is carried out at 260 to 320 ° C. for 20 to 60 minutes. When the powder coating material of the present invention is applied by rotrining, the fluororesin film is formed and fired at the same time.

The fluororesin film preferably has a film thickness after firing of 100 to 10,000 μm. If it is less than 100 μm, the excellent properties of the CTFE copolymer may not be sufficiently exhibited, and if it exceeds 10,000 μm, cracks and the like may occur. A more preferred upper limit is 5000 μm.

This invention is also a primer containing the said CTFE copolymer, a heat resistant resin, and a dispersion medium.

The above heat-resistant resin usually functions as a binder in the primer of the present invention.

The heat-resistant resin is not particularly limited as long as it is generally known as a resin having heat resistance, but is preferably one that dissolves in a heat-resistant resin dissolving solvent described later.

Such a heat resistant resin is preferably at least one selected from the group consisting of polyamideimide resin, polyethersulfone and polyimide resin from the viewpoint of heat resistance, solubility, etc., and two or more types are used. May be.

The solid content ratio between the CTFE copolymer and the heat resistant resin is 40:60 to 90:10 on a mass basis. If the amount of the CTFE copolymer is too small, the adhesiveness with the fluororesin film is deteriorated and delamination occurs, which is not preferable. If the amount is too large, the adhesion with the substrate is reduced. A preferable lower limit of the CTFE copolymer is 45:55, and a preferable upper limit is 80:20.

The primer of the present invention preferably contains a heat-resistant resin dissolving solvent for dissolving the heat-resistant resin. If it contains the heat-resistant resin-dissolving solvent, the heat-resistant resin is dissolved in the heat-resistant resin-dissolving solvent, uniformly dispersed in the primer, and spread throughout the substrate by coating. As a result, adhesion with the substrate can be improved.

The heat-resistant resin dissolving solvent is not particularly limited as long as it is a solvent capable of dissolving the heat-resistant resin, but preferably has a boiling point of 100 ° C. or higher, for example, N-methyl-2-pyrrolidone, N, N-dimethyl Examples include acetamide and N, N-dimethylformamide.

The heat-resistant resin-dissolving solvent is preferably 10% or more based on mass with respect to the heat-resistant resin. Within the above range, the heat-resistant resin can be spread on the substrate as described above, and the adhesion to the substrate can be improved. If it is less than 10%, the heat-resistant resin on the base material becomes non-uniform, resulting in poor adhesion. A more preferred lower limit is 50%. When the heat-resistant resin-dissolving solvent increases, the adhesion with the substrate tends to be improved. However, in view of industrial production, the preferable upper limit is usually 500%, and the more preferable upper limit is 350%.

The primer of the present invention contains a dispersion medium in addition to the above-mentioned CTFE copolymer and heat-resistant resin. The primer of the present invention is a dispersion in which the heat-resistant resin is dissolved in the heat-resistant resin-dissolving solvent and the CTFE copolymer is dispersed in the dispersion medium as a dispersoid. It becomes possible to apply to every corner on the substrate.

As the dispersion medium, at least one selected from the group consisting of water, alcohol, ketone, ester and aromatic hydrocarbon is used. As the dispersion medium, water is preferably used because it is preferable in terms of working environment.

When water is used as the dispersion medium, it is preferable to use a surfactant in order to disperse the CTFE copolymer. The surfactant is not particularly limited, and may be any nonionic, anionic or cationic surfactant, but is preferably one that evaporates or decomposes at a relatively low temperature of about 250 ° C. And anionic systems are more preferred.

When water is used as the dispersion medium, a rust inhibitor is required to prevent corrosion of the substrate during coating. It does not specifically limit as said rust preventive agent, For example, a dibutylamine etc. are mentioned.

As the dispersion medium, when the CTFE copolymer is used as a dispersion without isolating the resin component, the water used for the polymerization may be used as the dispersion medium, or water may be added separately. . When the dispersion of the CTFE copolymer obtained by emulsion polymerization is used as it is, the surfactant used for the polymerization may be used as a part or all of the surfactant as it is. Similarly, when the CTFE copolymer 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 primer of the present invention may contain a heat stabilizer in combination with the CTFE copolymer, the heat resistant resin and the dispersion medium. The primer of the present invention can reduce the thermal deterioration by containing the thermal stabilizer and preventing oxidation of the CTFE copolymer and the heat-resistant resin due to heating in the fluororesin film formation. As a result, the adhesion stability can be improved.

Although it does not specifically limit as said heat stabilizer, For example, a metal oxide, an amine antioxidant, an organic sulfur containing material, etc. are preferable.

The metal oxide is not particularly limited as long as it functions as a heat stabilizer, and examples thereof include oxides of typical metals such as Cu, Al, Fe, Co, and Zn.

As the amine-based antioxidant, in view of the heating step described above, an amine-based compound having stability even at 250 ° C. or higher is preferable, and examples thereof include aromatic amines, and examples thereof include dinaphthylamine and phenyl-α-naphthylamine. An amine derivative having a phenyl group or a naphthyl group, such as phenyl-β-naphthylamine, diphenyl-p-phenylenediamine, and phenylcyclohexyl-p-phenylenediamine, is preferable.

The organic sulfur compound is not particularly limited, and examples thereof include benzimidazole-based mercaptan-based compounds, benzothiazole-based mercaptan-based compounds, thiocarbamic acid, salts thereof, thiuram monosulfide, and the like. It does not specifically limit as said salt, For example, salts with Zn, Sn, Cd, Cu, Fe etc. are mentioned.

The said heat stabilizer can use 1 type (s) or 2 or more types.

The heat stabilizer is preferably a non-metallic compound that does not produce a residue when the primer of the present invention is used in the field of pharmaceuticals, semiconductors, etc., in which elution of metal ions is not desirable. Among the sulfur compounds, those other than metal salts are listed.

The heat stabilizer is preferably 0.001 to 5% on a mass basis with respect to the solid content of the CTFE copolymer. If it is less than 0.001%, the thermal stability effect may be insufficient, and if it exceeds 5%, the influence of foaming caused by the decomposition of the heat stabilizer may be increased. A preferred lower limit is 0.003% and a preferred upper limit is 2%.

The primer of the present invention may be used in combination with the above-described components and may contain additives as necessary. The additive is not particularly limited, and examples thereof include those used for general paint primers, and may be pigments, for example. The pigment is not particularly limited, and examples thereof include rust preventive pigments, fired pigments, and the like, in addition to colored pigments such as carbon, titanium oxide, dials, and mica.

The primer of the present invention is prepared by a conventionally known method, for example, by mixing the above-mentioned CTFE copolymer, heat resistant resin, dispersion medium, and surfactant, rust inhibitor and additives as necessary. And a method in which a heat-resistant resin-dissolving solvent is added and dispersed by stirring.

The present invention is also a primer film formed from the primer of the present invention. The primer film of the present invention can be obtained by applying the primer of the present invention to a substrate and appropriately drying and heating. Since the primer film of the present invention is formed from the primer of the present invention, it exhibits extremely excellent heat-resistant adhesion.

This invention is also an article | item characterized by having a base material, the primer film | membrane formed from the primer of this invention on the said base material, and the fluororesin film | membrane formed on the said primer film | membrane.

Examples of the substrate include those described above.

The method for applying the primer of the present invention to the substrate is not particularly limited, and can be appropriately selected depending on the form of the substrate, for example, spray coating, dip coating, brush coating, electrostatic coating, etc. A conventionally well-known method etc. are mentioned. The application can be performed such that the dry film thickness is 10 to 60 μm. Thus, the primer of the present invention can increase the crack limit thickness. The heating is performed at a temperature at which the above layer separation occurs or higher, for example, 60 to 120 ° C. Prior to the heating, drying may be performed at room temperature, and the heating conditions may be relaxed by drying.

The article of the present invention is formed by applying the primer of the present invention on the substrate and drying it to form a primer film, applying a fluororesin paint on the primer film, drying as necessary, and then firing. Thus, it can be produced by forming a fluororesin film.

The fluororesin coating is not particularly limited, and for example, one or more fluorines selected from the group of fluorine-containing monomers consisting of CTFE, trifluoroethylene, TFE, HFP, VdF, and PAVE. A paint containing a fluororesin obtained by polymerizing the containing monomer may be mentioned, which may be a liquid paint or a powder paint, but the powder paint of the present invention described above is particularly preferable. When the powder coating material of the present invention is used, the interlayer adhesion between the primer film and the fluororesin film is excellent due to the compatibility between the CTFE copolymers.

The present invention has a base material, a primer film formed from the primer of the present invention on the base material, and a fluororesin film formed from the powder paint of the present invention on the primer film. It is also an article.
When the primer film and the fluororesin film are respectively formed from the primer of the present invention and the powder coating material, the interlaminar adhesion between the primer film and the fluororesin film is particularly excellent, and excellent heat resistance An article exhibiting adhesion can be obtained.
As the substrate, those described above can be used.
The article is coated with the primer of the present invention on the substrate and dried to form a primer film. The powder coating of the present invention is coated on the primer film, then dried as necessary, and then fired. Then, it can be produced by forming a fluororesin film.

The powder coating material and primer of the present invention can be used in rice cookers, pots, hot plates, irons, frying pans, home bakery, etc. for home appliances and kitchens, and for industrial use, rolls for OA equipment, OA equipment Widely applied to mold release applications such as belts, paper rolls, calender rolls for film production, injection molds, etc .; corrosion resistance applications such as stirring blades, tank inner surfaces, vessels, towers, and centrifuges.

The use of the article of the present invention is not particularly limited. For example, coating materials for various electric wires such as heat-resistant enamel wires; information equipment parts (paper separation claw, printer guide, gear, bearing), connector, vernier socket, IC Sockets, oilfield electrical components, relays, electromagnetic shields, relay cases, switches, covers, terminal board buses and other electrical and electronic industry related applications; valve seats, hydraulic seals, backup rings, piston rings, wear bands, vanes, balls Bearing retainer, roller, cam, gear, bearing, labyrinth seal, pump parts, mechanical linkage, bushing, fastener, spline liner, bracket, hydraulic piston, chemical pump casing, valve, valve, tower packing, coil bobbin, packing, connector , Gasket Machine industry related applications such as valve seals; thrust washers, seal rings, gears, bearings, tappets, engine parts (pistons, piston rings, valve steers), transmission parts (spool valves, ball check valves, sealing), rocker arms Applications related to the vehicle industry such as jet engine parts (bushings, washers, spacers, nuts), power control clutches, door hinge bearings, connectors, tube clamps, brackets, hydraulic parts, antennas, radomes, frames, fuel system parts, compressor parts , Rocket engine parts, wearstrips, connector shelves, aerospace applications such as space structures, etc. In addition, there are applications such as iron making machine pin covers, plating equipment parts, nuclear power related parts, ultrasonic transducers, potentiometer shafts, faucet parts and the like.

Examples of the use of the article of the present invention include stirring blades, tank inner surfaces, vessels, towers, centrifuges, pumps, valves, piping, ventilation holes, ducts, heat exchangers, plating jigs, tank lorry inner surfaces, screw conveyors, etc. Corrosion-resistant applications; semiconductor-related applications such as semiconductor factory ducts; industrial mold release applications such as OA rolls, OA belts, papermaking rolls, film production calendar rolls, injection molds; rice cookers, pots, hot plates, irons, frying pans, Home bakery, pan tray, gas table top plate, pan top plate, pan, pot, and other household appliances and kitchen related applications; precision mechanism sliding members including various gears, paper rolls, calendar rolls, mold release parts, casings, valves, Valve, packing, coil bobbin, oil seal, joint, antenna cap, connector, gasket, Rubushiru, buried bolts, industrial parts related applications such as built-in nut and the like.

Since the powder coating material and primer of the present invention have the above-described configuration, it is possible to obtain a film that is excellent in heat-resistant adhesion and hardly generates blisters.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1
Chlorotrifluoroethylene copolymer powder obtained by suspension polymerization having a molar ratio of chlorotrifluoroethylene / tetrafluoroethylene / perfluoropropyl vinyl ether of 28/70/2 (melt flow rate at 297 ° C .: 15 g / 10 Min, average particle diameter 37 μm) 30 g, polyamideimide N-methyl-2-pyrrolidone solution 37 g as a binder component, surfactant (trade name: Nonion HS-208, manufactured by NOF Corporation), antirust agent ( 1 g of dibutylamine) and 13 g of pure water were placed in a stainless steel solution and dispersed while stirring using a propeller stirrer to obtain a primer.

Using alumina (trade name: Tosa Emery, manufactured by Uji Electric Chemical Co., Ltd., 80 mesh: 100 mesh = 5: 5), blasting is performed on a degreased stainless steel substrate (SUS430) at a pressure of 0.59 MPa. After removing the blast powder with air, the primer was applied by spraying and dried at 80 ° C. for 30 minutes to obtain a primer film.

Next, a powder coating material having a molar ratio of chlorotrifluoroethylene / tetrafluoroethylene / perfluoropropyl vinyl ether of 28/70/2 (melt flow rate at 297 ° C .: 15 g / 10 min, average particle size: 37 μm) is electrostatically applied. It was applied onto the primer film by painting and baked at 300 ° C. for 30 minutes. A powder coating material was further applied on the obtained film by electrostatic coating and baked at 300 ° C. for 40 minutes to obtain a test piece.

Comparative Example 1
Ethylene / tetrafluoroethylene copolymer powder (at 297 ° C.) obtained by emulsion polymerization in which the molar ratio of ethylene / tetrafluoroethylene / CH ₂ = CFC ₃ F ₆ H is 31.8 / 66.0 / 2.2 Melt flow rate of 13 g / 10 min, average particle size 80 μm) 30 g, polyamideimide N-methyl-2-pyrrolidone solution 37 g as a binder component, and surfactant (trade name: Nonion HS-208, manufactured by NOF Corporation) ) 3 g, 1 g of a rust inhibitor (dibutylamine) and 13 g of pure water were placed in a stainless steel solution and dispersed while stirring using a propeller stirrer to obtain a primer.

Using alumina (trade name: Tosa Emery, manufactured by Uji Electric Chemical Co., Ltd., 80 mesh: 100 mesh = 5: 5), blasting is performed on a degreased stainless steel substrate (SUS430) at a pressure of 0.59 MPa. After removing the blast powder with air, the primer was applied by spraying and dried at 80 ° C. for 30 minutes to obtain a primer film.

Next, a powder coating material having a molar ratio of ethylene / tetrafluoroethylene / hexafluoroisobutylene of 31.8 / 66.0 / 2.2 (melt flow rate at 297 ° C .: 13 g / 10 min, average particle size: 35 μm) was statically removed. It apply | coated on the said primer film | membrane by electropainting and baked for 30 minutes at 300 degreeC. A powder coating material was further applied on the obtained film by electrostatic coating and baked at 300 ° C. for 40 minutes to obtain a test piece.

Evaluation of hot water resistance The evaluation of hot water resistance was performed using a lining tester (trade name: Yamazaki type lining tester LA-15, manufactured by Yamazaki Seiki Laboratories Co., Ltd.) that is generally used in the corrosion resistance test of resin linings. . The panel is attached to both ends of a cylindrical cell made of heat-resistant glass horizontally filled with pure water 60 to 70% so as to close the cylindrical cell, and a test piece is put into a liquid phase and a vapor phase of pure water at a predetermined temperature. For a predetermined test time. The results are shown in Table 2.

Evaluation criteria (circle): A blister was not observed.
(Triangle | delta): Generation | occurrence | production of blister was very small.
X: Generation | occurrence | production of blister was observed.

The powder coating material and primer of the present invention are suitable for applications requiring heat resistance.

Claims (22)

A powder coating containing a chlorotrifluoroethylene copolymer,
The chlorotrifluoroethylene copolymer includes a chlorotrifluoroethylene unit, a tetrafluoroethylene unit, and a monomer derived from a monomer [A] copolymerizable with chlorotrifluoroethylene and tetrafluoroethylene [A]. ] Unit,
The chlorotrifluoroethylene unit and the tetrafluoroethylene unit are 90 to 99.9 mol% in total, and the monomer [A] unit is 0.1 to 10 mol%. Powder paint. Monomer [A] is ethylene, vinylidene fluoride, perfluoro (alkyl vinyl ether), and the following general formula (I)
CX ³ X ⁴ = CX ¹ (CF ₂ ) _n X ² (I)
(Wherein X ¹ , X ³ and X ⁴ are the same or different and represent a hydrogen atom or a fluorine atom, X ² represents a hydrogen atom, a fluorine atom or a chlorine atom, and n is an integer of 1 to 10) The powder coating material according to claim 1, which is at least one selected from the group consisting of vinyl monomers represented by: The monomer [A] is represented by the following general formula (II)
^{_{CF 2 = CF-ORf 1 (}} II)
The powder coating material according to claim 1 or 2, wherein Rf ¹ is a perfluoro (alkyl vinyl ether) represented by (wherein Rf ¹ represents a perfluoroalkyl group having 1 to 8 carbon atoms). The powder coating material according to claim 1, 2 or 3, wherein the chlorotrifluoroethylene unit is 10 to 90 mol% of the total of the chlorotrifluoroethylene unit and the tetrafluoroethylene unit. The powder coating material according to claim 1, 2, 3, or 4, wherein the chlorotrifluoroethylene unit is 20 to 90 mol% of the total of the chlorotrifluoroethylene unit and the tetrafluoroethylene unit. The powder paint according to claim 1, 2, 3, 4 or 5, wherein the chlorotrifluoroethylene copolymer has a melt flow rate of 0.1 to 70 (g / 10 min). The powder coating material according to claim 1, 2, 3, 4, 5, or 6, wherein the temperature [Tx] at which 1% by mass of the chlorotrifluoroethylene copolymer is decomposed is 370 ° C or higher. A fluororesin film formed from the powder paint according to claim 1, 2, 3, 4, 5, 6 or 7. A base material, a primer film formed on the base material, and a fluororesin film formed from the powder paint according to claim 1, 2, 3, 4, 5, 6 or 7 on the primer film Article characterized by that. A primer containing a chlorotrifluoroethylene copolymer, a heat resistant resin and a dispersion medium,
The chlorotrifluoroethylene copolymer includes a chlorotrifluoroethylene unit, a tetrafluoroethylene unit, and a monomer derived from a monomer [A] copolymerizable with chlorotrifluoroethylene and tetrafluoroethylene [A]. ] Unit,
The chlorotrifluoroethylene unit and the tetrafluoroethylene unit are 90 to 99.9 mol% in total, and the monomer [A] unit is 0.1 to 10 mol%,
The primer characterized in that the solid content ratio of the chlorotrifluoroethylene copolymer and the heat-resistant resin is 40:60 to 90:10 on a mass basis. Monomer [A] is ethylene, vinylidene fluoride, perfluoro (alkyl vinyl ether), and the following general formula (I)
CX ³ X ⁴ = CX ¹ (CF ₂ ) _n X ² (I)
(Wherein X ¹ , X ³ and X ⁴ are the same or different and represent a hydrogen atom or a fluorine atom, X ² represents a hydrogen atom, a fluorine atom or a chlorine atom, and n is an integer of 1 to 10) The primer according to claim 10, which is at least one selected from the group consisting of vinyl monomers represented by: The monomer [A] is represented by the following general formula (II)
^{_{CF 2 = CF-ORf 1 (}} II)
The primer according to claim 10 or 11, which is perfluoro (alkyl vinyl ether) represented by the formula (wherein Rf ¹ represents a perfluoroalkyl group having 1 to 8 carbon atoms). The primer according to claim 10, 11 or 12, wherein the chlorotrifluoroethylene unit is 10 to 90 mol% of the total of the chlorotrifluoroethylene unit and the tetrafluoroethylene unit. The primer according to claim 10, 11, 12, or 13, wherein the chlorotrifluoroethylene unit is 20 to 90 mol% of the total of the chlorotrifluoroethylene unit and the tetrafluoroethylene unit. The primer according to claim 10, 11, 12, 13 or 14, wherein the chlorotrifluoroethylene copolymer has a melt flow rate of 0.1 to 70 (g / 10 min). The primer according to claim 10, 11, 12, 13, 14, or 15, wherein the chlorotrifluoroethylene copolymer has a temperature [Tx] at which 1% by mass decomposes is 370 ° C. or more. Furthermore, it contains a heat-resistant resin dissolving solvent,
The heat-resistant resin dissolving solvent is at least one selected from the group consisting of N-methyl-2-pyrrolidone, N, N-dimethylacetamide, and N, N-dimethylformamide, and is 10 on a mass basis with respect to the heat-resistant resin. The primer according to claim 10, 11, 12, 13, 14, 15, or 16, which is contained in an amount of at least%. The primer according to claim 10, 11, 12, 13, 14, 15, 16, or 17, wherein the heat resistant resin is at least one selected from the group consisting of polyamideimide resin, polyethersulfone and polyimide resin. The heat stabilizer according to claim 10, 11, 12, 13, 14, 15, 16, 17 or 18, further comprising 0.001 to 5% by mass based on the solid content of the chlorotrifluoroethylene copolymer. Primer. A primer film formed from the primer according to claim 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19. A substrate, a primer film formed from the primer according to claim 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 on the substrate, and fluorine formed on the primer film An article having a resin film. A substrate, a primer film formed from the primer according to claim 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19 on the substrate, and claim 1 on the primer film, An article comprising a fluororesin film formed from the powder paint according to 2, 3, 4, 5, 6 or 7.