JP2011202033A - Coating composition, method for producing film using the same, and coated body using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a primer composition containing chromium-free fluororesin, which can provide a coated body having excellent higher anti-corrosiveness by providing a fluororesin film and a primer layer having sufficient adhesive strength together with the fluororesin film to the surface of a base material such as metal, glass, ceramic, and heat resistant plastic, and to provide a method for producing a film using the primer composition, and a coated body using the primer composition.SOLUTION: A coating composition is provided, which contains fluororesin the melt flow rate (MFR) of which measured at 372°C under a load of 5 kg on the basis of ASTM D1238 is 10-100 g/10 min and organic titanate, wherein the titanium content of the organic titanate with respect to the fluororesin is 1-40 wt.%. There are also provided a method for producing a film using the coating composition, and a coated body using the coating composition.

Description

  The present invention relates to a coating composition containing a fluororesin, a film production method using the same, and a film body. More specifically, the present invention relates to a coating composition that can be suitably used for a primer layer effective for forming a fluororesin coating on metal, glass, ceramic, plastic, etc., and a coating production method and coating using the coating composition.

  Since the fluororesin has excellent non-adhesiveness, it has a wide range of uses for articles that require various non-adhesive properties such as frying pans, pan molds, rice cookers. However, compared with other resins, excellent non-tackiness can be obtained due to surface free energy, but on the other hand, it is difficult to adhere to other substances, so a fluororesin coating film on the substrate There is a problem that the formation of is not easy.

  For example, fluororesins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene (FEP) are water and oil repellent and wear resistant. It is used in various applications because of its excellent properties such as anti-fouling property, antifouling property, heat resistance, and chemical resistance, but is generally expensive and may have insufficient mechanical strength and dimensional stability. . Therefore, various attempts have been made to bond the fluororesin coating to other base materials such as metal, glass, ceramic, and plastic in order to make up for the disadvantages while taking advantage of the advantages of the fluororesin.

  When coating fluororesin on metal, ceramic, glass, plastic surfaces, etc., as a pre-treatment, after forming physical irregularities on the surface of these substrates by methods such as sandblasting, etching, etc., a primer having adhesiveness A method of applying a composition to the surface of a base material to form a primer layer, and bonding the base material and a fluororesin as a topcoat layer through this primer layer is generally widely performed. In this method, an anchor effect (an anchoring effect) is used for adhesion between the substrate surface and the primer layer, in which the adhesion area between the primer layer and the substrate surface increases due to the unevenness of the substrate surface, thereby improving the adhesive force. (See Patent Document 1).

  As the primer layer, a mixture obtained by adding a mixture of phosphoric acid and chromic acid to a fluororesin, polyethersulfone resin (PES), polyamideimide resin (PAI), polyimide resin (PI), polyphenylene sulfide resin (PPS), etc. And the like, in which a fluororesin is added (see Patent Documents 2, 3, 4, and 5).

In addition, the fluororesin generally needs to be thickened in corrosion resistant applications, and in order to make it thicker, a powder coating made of fluororesin is applied and repeatedly baked at a temperature equal to or higher than the melting point of the fluororesin. It needs to be painted. The primer is required to have heat resistance that can withstand the firing at a high temperature for a long time and can maintain the adhesion to the substrate or the like.
As a primer excellent in heat-resistant adhesion, a chromium phosphate primer having excellent resistance to long-time high-temperature firing is widely used. However, awareness of environmental issues has increased, and there has been a strong demand for many years to develop a chromium-free primer that does not contain hexavalent chromium and has strong heat-resistant adhesion comparable to a chromium phosphate primer.

  Combinations of fluororesin and various binder resins have been studied as chromium-free primers. As the binder resin, use of polyphenylene sulfide (PPS) has been proposed from the viewpoint of heat resistance. However, PPS is inferior in compatibility with the fluororesin and has a problem that the adhesion with the fluororesin layer is insufficient.

  In order to improve adhesion with the fluororesin layer, it has been proposed to add polyamideimide (PAI) and / or polyimide (PI) to PPS as a binder resin in a chromium-free primer (see Patent Documents 6 and 8). However, these proposed chromium-free primers still have insufficient heat-resistant adhesion.

  Also, an aqueous dispersion chromium-free primer that can be applied to a smooth surface using PPS and PAI as a binder resin has been proposed (see Patent Document 7). In this proposal, two types of fluororesins having different melt viscosities are specified. It is characterized by being blended in a quantitative ratio, and there is a problem that heat-resistant adhesion deteriorates when fired for a long time.

  Furthermore, a primer coating composition comprising a polyamideimide resin (PAI) and a polyphenylene sulfide resin (PPS) that is 0.1 to 20% by mass of the total amount has been proposed (see Patent Document 9). Further improvement in heat-resistant adhesion is also required for these primers.

  In addition, a primer layer having a structure in which a first primer layer containing a fluororesin and an organic titanate having a strong inorganic character and a second primer layer containing a fluororesin and polyphenylene sulfide are sequentially laminated has been proposed ( Patent Document 10).

JP 2001-219122 A JP-A-11-29736 JP 2003-183565 A Japanese Patent No. 2702401 JP 2003-53261 A JP-A-53-74532 US Pat. No. 5,789,083 Japanese Patent Laid-Open No. 8-322732 International Publication WO2004 / 048489 Japanese Patent No. 4034784

  When using a mixture of chromic acid and phosphoric acid as in the case of conventional chromium phosphate primers, there is no problem of poor solvent resistance, high temperature resistance, and corrosion resistance. The load is large. When the primer layer contains an adhesive organic resin, there is a problem that the primer portion in the structure after being bonded to glass or metal has poor solvent resistance, high temperature resistance, and further corrosion resistance.

  The present invention obtains a coating body with higher corrosion resistance by providing a primer layer having sufficient adhesion to the fluororesin coating on the surface of a substrate such as a metal, glass, ceramic, heat-resistant plastic, etc. A chromeless fluororesin-containing primer composition is provided.

  In addition, the present invention provides a surface modification method using a fluororesin that eliminates the disadvantages observed in the conventional surface modification methods of fluororesins, is industrially easy to use, and has sufficient paintability and adhesion. With the goal.

  Therefore, the present inventor conducted extensive research to solve the above problems, and as a result, the solvent resistance, high temperature resistance, and corrosion resistance of the fluororesin did not decrease, and the metal has a low environmental load. It has been found that it has adhesiveness, etc., and has led to the present invention.

  That is, the present invention contains a fluororesin and an organic titanate having a melt flow rate (MFR) measured at a load of 5 kg and 372 ° C. of 10 to 100 g / 10 min in accordance with ASTM D1238, There is provided a coating composition characterized in that the titanium content contained in titanate is 1 to 40% by weight.

  Alkoxy titanium, titanium acylate or titanium having a structure in which the organic titanate includes Ti—IV bond formed by Ti (IV) or Ti (III) and a compound having an alcoholic hydroxyl group, a phenolic hydroxyl group or a carboxyl group A coating composition that is a chelate is a preferred embodiment of the present invention.

  The composition further comprises a reactive functional group-containing fluororesin which is a tetrafluoroethylene / compound having a reactive functional group / fluorine-containing comonomer copolymer at a ratio of 0 to 99% by weight with respect to the fluororesin. The above-mentioned coating composition containing is a preferred embodiment of the present invention.

  The above-mentioned coating composition in which the compound having a reactive functional group is a trifluorovinyl ether group-containing phosphate compound is a preferred embodiment of the present invention.

  The present invention also provides a method for producing a coated body in which the above-described coating composition is applied, the liquid solvent is removed, and then fired.

  The present invention further provides a coated body having an average thickness of 1 to 300 μm formed on the substrate by the above-described film manufacturing method.

  The present invention still further provides the coating body, wherein the substrate is any one of metal, ceramic, stainless steel, glass, and heat resistant plastic.

The specific coating composition of the present invention and the coating using the coating composition exhibit good adhesion to metals, ceramics, glass, heat-resistant plastics and the like despite containing the fluororesin.
The specific coating composition provided by the present invention is inferior in solvent resistance, high temperature resistance and abrasion resistance because the component contributing to adhesion to a substrate such as metal contains organic titanate having a strong inorganic character. There will be no problem.
The coated body provided by the present invention does not cause a problem that it is inferior in solvent resistance or high temperature resistance as compared with a conventional method in which an organic resin having adhesion to a metal or glass is added to a fluororesin. .
Moreover, compared with the conventional film body which contains the mixture of chromic acid and phosphoric acid in a fluororesin, it becomes possible to reduce the burden on an environment.

The fluororesin used in the present invention is heat-meltable, and is unsaturated fluorinated hydrocarbon, fluorinated chlorohydrocarbon, ether group-containing fluorinated hydrocarbon, phosphoric dihydrogen ester group-containing fluorinated hydrocarbon A polymer or copolymer of unsaturated fluorinated hydrocarbons, or a copolymer of these unsaturated fluorinated hydrocarbons and ethylene.
For example, a polymer of a monomer selected from tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, fluoroalkoxytrifluoroethylene, vinylidene fluoride and vinyl fluoride, or a copolymer of these monomers and ethylene, Examples thereof include a copolymer of a fluorovinyl phosphoric acid dihydrogen ester compound and a fluorine-containing comonomer. These can be used alone or as a mixture of two or more. Based on ASTM D1238 of fluororesin, the melt flow rate (MFR) measured with a load of 5 kg and 372 ° C. ± 0.1 is 10 to 100 g / 10 min fluororesin. Preferably it is 10-50 g / 10min, More preferably, it is 30-40 g / 10min. When the MFR of the fluororesin is within this range, a film having excellent corrosion resistance and adhesion can be obtained.

  Specific examples of the fluororesin include tetrafluoroethylene / fluoroalkoxytrifluoroethylene copolymer (hereinafter referred to as PFA), tetrafluoroethylene / hexafluoropropylene copolymer (hereinafter referred to as FEP), and tetrafluoroethylene / ethylene copolymer. , Tetrafluoroethylene / hexafluoropropylene / perfluoro (alkyl vinyl ether) copolymer, polychlorotrifluoroethylene, chlorotrifluoroethylene / ethylene copolymer, polyvinylidene fluoride, or a combination of two or more of these can do. In consideration of film formability, it is preferable to use PFA or FEP.

PFA is a crystalline copolymer of tetrafluoroethylene and fluoroalkoxytrifluoroethylene as represented by the following formula (1) or formula (2), and is a known method such as solution polymerization, emulsion polymerization, suspension polymerization, etc. It can be manufactured by. PFA is capable of melt molding such as melt extrusion molding and injection molding.

（式中、ＸはＨまたはＦを表し、ｎは０〜４の整数、ｍは０〜７の整数である。）

(In the formula, X represents H or F, n is an integer of 0 to 4, and m is an integer of 0 to 7.)

（式中、ｑは０〜３の整数である。）

(In the formula, q is an integer of 0 to 3.)

Preferred fluoroalkoxytrifluoroethylenes include perfluoro (methyl vinyl ether) (PMVE), perfluoro (ethyl vinyl ether) (PEVE), perfluoro (propyl vinyl ether) (PPVE), perfluoro (isobutyl vinyl ether) and the like perfluoro (isobutyl vinyl ether). Alkyl vinyl ether). In particular, perfluoro (ethyl vinyl ether) (PEVE) and perfluoro (propyl vinyl ether) (PPVE) are preferable. The content of fluoroalkoxytrifluoroethylene in the PFA is preferably 3% by weight or more from the viewpoint of durability, and more preferably 5% by weight or more. Content in PFA can be suitably selected according to the objective of this invention.

  In the present invention, the content of the fluororesin in the coating is not particularly limited, but is preferably 60 to 96% by weight, and more preferably 77 to 91% by weight. This is because if the content of the fluororesin in the coating is less than 60% by weight or more than 96% by weight, sufficient adhesion to the substrate tends not to be obtained.

  The coating composition and the coating using the coating composition in the present invention contain an organic titanate as a component that imparts adhesiveness. Here, the organic titanate according to the present invention is soluble in water when forming a coating containing a fluororesin using an aqueous coating material, and in order to ensure the stability of the coating composition until coating, It is not particularly limited as long as it is stable (specifically titanium lactate or titanium triethanolamate), but Ti (IV) or Ti (III) and alcoholic hydroxyl group, phenolic hydroxyl group or carboxyl Alkoxy titanium, titanium acylate, or titanium chelate having a structure including a Ti—O—C bond formed by a compound having a group is preferable. Among these, from the viewpoint of solubility in water and stability in water, titanium diisopropoxybis (triethanolaminate) or a similar compound is preferable, and it does not decompose even at high temperatures (about 300 to 400 ° C.). In particular, titanium diisopropoxybis (triethanolaminate) in which organic residues remain after primer baking is coordinated. Further, the organic titanate may be a condensation product of titanium lactate, ammonium titanium lactate, titanium acetylacetonate ammonium lactate, or other diisopropoxy titanium bisacetylacetonate. Note that whether or not the organic titanate is contained in the coating is determined by, for example, detecting titanium atoms with an X-ray photoelectron spectrometer (XPS) or using a Fourier transform infrared spectrophotometer (FT-IR) with Ti-O-C. It can be estimated by confirming the binding-derived absorption.

  In the coating film formed on the substrate, the organic titanate has a good steam property, and the ratio of the titanium component in the organic titanate with respect to the fluororesin is preferable from the viewpoint of realizing a coating body with reduced environmental load. Is more preferably contained in an amount of 1 to 40% by weight and 9 to 23% by weight. The ratio of the Ti component in the organic titanate to the fluororesin in this coating is, for example, incinerated at a temperature above the temperature at which the fluororesin decomposes and gasifies the coating formed on the substrate, and the weight of the residue is measured. Can be estimated.

  In the coating composition of the present invention and the film using the coating composition, the kind of fluororesin to be mixed is not particularly limited, but the fluororesin further has tetrafluoroethylene / reactive functional group. When a reactive functional group-containing fluororesin that is a compound / fluorine-containing comonomer copolymer is contained, the adhesion to the substrate can be further improved. Such reactive functional group-containing fluororesin is preferably contained in an amount of 0 to 99% by weight, preferably 5 to 90% by weight, based on the fluororesin.

Examples of the compound having a reactive functional group, -COOR _(R is _-H, represents a _{-CH 3, -C 2 H 5,} -C 3 H 7, -C 4 H 9, or _-C 5 _{H 11)} , _-CH 2 COOR (R is _-H, represents a _{-CH 3, -C 2 H 5,} -C 3 H 7, -C 4 H 9, or _{-C 5 H 11), - COF} , -CONH 2, _{-CH 2 OH, -OH, -CN,} -CH 2 O (CO) NH 2, -CH 2 OCN, -CH 2 OP (O) (OH) 2, CH 2 P (O) Cl 2, -SO 4 _H, -SO 3 _H, can be mentioned a monomer having a functional group such as -SO ₂ F.

Preferable examples of the compound having a reactive functional group include a trifluorovinyl ether group-containing phosphate compound. A preferred example of the trifluorovinyl ether group-containing phosphate compound is a dihydrogen phosphate compound represented by the following formula (3).
CF ₂ = CF (OR) _m (CH ₂ ) OP (O) (OH) ₂ (3)
(In the formula, R represents a perfluoroalkyl group or a perfluoroalkoxy group having 1 to 20 carbon atoms, and m is an integer of 1 to 10. When m is 2 or more, each R is the same. Or different.)

  As the fluorine-containing comonomer constituting the reactive functional group-containing fluororesin, the above-mentioned perfluoro (alkyl vinyl ether) or perfluoro (alkyl vinyl) is preferable.

The content of the monomer unit having a reactive functional group in the tetrafluoroethylene / monomer having a reactive functional group / fluorine-containing comonomer copolymer is 0.02 to 10 mol%, preferably 0.02 to 5%. It is desirable to be mol%.
Moreover, as content of a fluorine-containing comonomer copolymer unit, it is 3-15 mol%, It is desirable that it is 5-12 mol% preferably. Examples of such reactive functional group-containing fluororesins include those disclosed in JP-A-2005-212318.

  In the fluororesin having a functional group, the mixing form with the other fluororesin is not particularly limited, but a simple blending method or other one having a core / shell structure formed on the outer periphery of the fluororesin should be used. Can do. Among these, from the viewpoint of handling the resin, it is preferable to use a fluororesin having a core / shell structure as described in Japanese Patent No. 28825579.

  In addition to the fluororesin and organic titanate, the coating composition in the present invention preferably contains a surfactant as necessary. The surfactant is not particularly limited, but it does not cause separation until the composition for forming the film is uniformly mixed and the film is dried, so that many residues do not remain after baking. Is preferred.

  The content of the surfactant is not particularly limited, but is preferably 0.01 to 10% by weight, and more preferably 0.5 to 5% by weight. This is because when the surfactant content is less than 0.01% by weight, a uniform mixed state tends not to be maintained, and when it exceeds 10% by weight, a large amount of carbon remains during baking. This is because the film forming property tends to be adversely affected.

  Further, the coating composition of the present invention may further contain a filler, a pigment, a pH adjuster, a thickener, a conductive material, a heat-resistant plastic, etc., as necessary, as long as the effects of the present invention are not impaired. Good. As the filler, the pigment, the pH adjuster, the conductive material, the heat-resistant plastic, and the like, any appropriate ones conventionally used in this field can be used and are not particularly limited. Moreover, the adjustment method of the coating composition of this invention is not specifically limited, A conventionally well-known adjustment method can be used. For example, the coating composition can be prepared by stirring and mixing the fluororesin aqueous dispersion and the organic titanate at room temperature.

  The base material used in the present invention is not particularly limited, and examples thereof include metals such as aluminum, iron, and stainless steel, glass, ceramics, heat resistant plastics, and clad materials of aluminum and stainless steel.

  The average thickness of the coating in the present invention is preferably 1 to 300 μm, and more preferably 5 to 50 μm. This is because if this film is too thin, uniform adhesion tends to be difficult to obtain, and if it is too thick, problems such as foaming and shrinkage stress of the film itself tend to increase.

  A film body comprising at least two layers in which a top layer in which a film using the coating composition in the present invention is used as a primer layer and a fluororesin layer or a fluororesin-containing layer is formed thereon is preferable. It is an aspect. Examples of the fluororesin used therein are the same as those described above. Of these, PTFE, PFA and FEP are preferred. In the present invention, the fluororesins contained in the primer layer may be the same or different from each other.

  Although the content rate of the fluororesin in a topcoat layer is not specifically limited, It is preferable that it is 20-100 weight%, and it is more preferable that it is 30-100 weight%. This is because if the content of the fluororesin in the top coat layer is too low, sufficient adhesion between the phase with the primer layer tends to be difficult to obtain.

  An intermediate layer may be formed between the primer layer and the topcoat layer. The intermediate layer may be composed of a plurality of layers. Examples of the fluororesin contained in the intermediate layer include those described above as the fluororesin contained in the primer layer. Among these, PTFE, PFA or FEP is preferable. The suitable MFR of the fluororesin contained in the intermediate layer is the same as described above. In the present invention, the fluororesin contained in the primer layer and the fluororesin contained in the intermediate layer may be the same or different from each other.

  Although the content rate of the fluororesin in the intermediate layer is not particularly limited, it is more preferably 20 to 98% by weight from the viewpoint of obtaining sufficient adhesive strength between the primer layer and 30 to 90% by weight. % Is more preferred.

  The intermediate layer preferably contains a polyphenylene sulfide resin from the viewpoint of further imparting the effect of improving the corrosion resistance. The content of the polyphenylene sulfide resin is not particularly limited, but is preferably 1 to 50% by weight, and more preferably 5 to 10% by weight. This is because too much polyphenylene sulfide resin tends to lower the solvent resistance and chemical resistance of the fluororesin.

  In addition, it is preferable that the intermediate | middle layer contains the glass flake from a viewpoint which can further provide the effect which suppresses osmosis | permeation. The content of glass flakes is not particularly limited, but is preferably 1 to 30% by weight, and more preferably 5 to 15% by weight.

  The intermediate layer may further contain a filler, a pigment, a pH adjuster, a conductive material, a heat resistant plastic, and the like as long as the effect of the present invention is not hindered. A filler, a pigment, a pH adjuster, a conductive material, a heat-resistant plastic, and the like can be appropriately selected from those conventionally used in this field and are not particularly limited.

  The intermediate layer is preferably formed to have a thickness of 10 to 5000 μm, and more preferably 30 to 1000 μm. This is because if the primer layer is too thin, it tends to be difficult to form a uniform film, and if it is too thick, the adhesiveness to the primer layer tends to decrease due to the shrinkage stress of the intermediate layer itself. The average thickness of the intermediate layer can be measured in the same manner as the primer layer.

  When the intermediate layer contains a fluororesin and a polyphenylene sulfide resin, high durability is obtained, and sufficient adhesion to the base material and adhesion of the fluororesin coated thereon can be secured.

The method for forming the film of the present invention will be described below. In the present invention, a layer formed on a substrate is referred to as a coating, and an article having a coating formed on a substrate is referred to as a coating body.
First, the composition for forming the film used as a primer layer on a base material is prepared, this is apply | coated to a base material and baked, and a primer layer is formed. As a coating composition for forming the primer layer, a fluororesin and an organic titanate, and if necessary, a surfactant and other components are dispersed in water and applied to a substrate. The coating method is not particularly limited, and the coating can be performed by a conventionally known appropriate method such as spray coating, dipping, or casting. Among these, from the viewpoint of handling the paint, it is preferable to apply the paint by spray coating. Further, the baking (firing) conditions in forming the primer layer are not particularly limited. For example, the conditions of baking for 5 to 180 minutes at the temperature of 150-450 degreeC are illustrated. Baking at a temperature of 200 to 300 ° C. for 5 to 180 minutes is preferable, and baking at a temperature of 250 ° C. for 5 to 180 minutes is more preferable. Such firing can be performed using, for example, an electric furnace. In addition, you may make it dry the said composition after apply | coating the composition which forms a primer layer, and before baking. Drying can be performed under appropriate conditions. You may bake by performing these application | coating, the process of drying and baking several times as needed.

  Next, a composition for forming the intermediate layer is prepared, applied to a substrate, and baked to form the intermediate layer. As a composition for forming the intermediate layer, a dispersion containing a fluororesin, a polyphenylene sulfide resin, and other components as necessary is prepared. Commercially available products MP-501 (Mitsui / Du Pont Fluoro Chemical Co.) and MP-502 (Mitsui / Du Pont Fluoro Chemical Co.) can also be suitably used for the composition. The application method is not limited, and it is preferable to apply the paint by a conventionally known method such as electrostatic coating or fluid dipping. The conditions for baking (firing) in the formation of the intermediate layer are not particularly limited. For example, the conditions of baking for 5 to 180 minutes at the temperature of 300-450 degreeC are illustrated. Such firing can be performed using, for example, an electric furnace. In addition, you may make it dry the said composition before baking after coating the composition which forms intermediate | middle layer. Drying can be performed under appropriate conditions. These coating (drying) and baking methods may be performed several times to form a plurality of intermediate layers.

  The substrate of the present invention is not particularly limited as long as it can withstand the heat of baking, but it is also used for metals, glass, ceramics, heat-resistant plastics and the like that are difficult to adhere to fluororesins. it can. Of these, metals are particularly suitable. The base material may be subjected to an appropriate surface treatment (for example, blasting, plating, silane coupling, etc.) in advance in order to increase the adhesive force with the primer layer.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.
The raw materials and test methods used in the examples and comparative examples are as follows.

Raw material (A) Fluororesin (I)
Tetrafluoroethylene / perfluoro (ethyl vinyl ether) copolymer (PFA), MFR: 30-40 g / 10 min (B) Fluororesin (II)
Tetrafluoroethylene / perfluoro (propyl vinyl ether) copolymer (PFA), MFR: 11-18 g / 10 min (C) Fluororesin (III)
Tetrafluoroethylene / perfluoro (propyl vinyl ether) copolymer (PFA), MFR: 1-3 g / 10 min (D) Fluororesin (IV)
MP-102, manufactured by Mitsui DuPont Fluorochemicals, Tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (PFA) powder coating (E) Fluororesin (V)
MP-501, manufactured by Mitsui & DuPont Fluorochemicals, polyphenylene sulfide-containing tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (PFA) powder coating (F) fluororesin (VI)
MP-502, manufactured by Mitsui & DuPont Fluorochemicals, Inc. Filler-containing tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (PFA) powder coating (G) Fluororesin (VII)
MP-505, manufactured by Mitsui & DuPont Fluorochemicals, Inc. Filler-containing tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (PFA) powder coating (H) Fluororesin (VIII)
MP-630, manufactured by Mitsui DuPont Fluoro Chemical Co., Ltd., filler-containing tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (PFA) powder coating (I) reactive functional group-containing fluororesin Tetrafluoroethylene / perfluoro (ethyl vinyl ether) copolymer / trifluorovinyl ether group-containing phosphate ester copolymer (12% by weight of PEVE, 0.6% by weight of EVE-P) Contains)
(J) Organic titanate ORGATICS TC-400 (Matsumoto Fine Chemical)

Test Method (1) Corrosion Resistance The test piece was left in an autoclave at 170 ° C. in 0.8 megapascal water vapor for 50 hours, and then slowly cooled to room temperature. Then, using 10% by weight saline as a chemical solution, immerse the test piece and incubate at 100 ° C, and visually check the occurrence of blisters, blisters (eczema-like blisters), and the presence or absence of corrosion every week for 4 weeks. The state in which the swelling was 2 mm or more, the number of blisters was 3 or more, and corrosion was observed was determined as adhesion failure, and the time until the adhesion failure was displayed.

(2) Adhesive strength Cut the laminate formed with an adhesive strength test piece to a width of 10 mm, from the masking portion (the fluororesin laminate portion without the primer layer) toward the fluororesin laminate portion with the primer layer, The masking part was peeled off and the peeled masking part (the fluororesin laminate part without the primer layer) was protected with a masking tape.
Measurement of adhesion:
Using a Tensilon universal testing machine (manufactured by A & D Co., Ltd.), the part protected by masking tape in accordance with the measuring method of adhesive peel strength (90 degree peel test method) specified in JIS K6854 The sample was sandwiched between chucks of a testing machine and pulled at a speed of 50 mm / min, and the adhesion of the fluororesin laminate having the primer layer was measured. The unit is kgf / cm.

(3) Steam-proof adhesion strength After leaving the test piece in 170 degreeC and 0.8 megapascal water vapor | steam for 100 hours, it cooled slowly to normal temperature and measured adhesion strength by said method. The unit is kgf / cm.
(4) Heat resistance The test piece was heated at 380 ° C. for 1 hour in an electric furnace, and then slowly cooled to room temperature. This was performed for 11 cycles, and the adhesion was measured by the above method. The unit is kgf / cm.

(Preparation Example 1)
Coating compositions (1) to (5) were prepared by mixing the fluororesin aqueous dispersion, organic titanate, thickener and water shown in Table 1. In Table 1, the unit of the amount of each component is parts by weight.

Example 1
Preparation of three-layer coating:
The substrate was shot blasted with # 60 alumina using SUS304. After spray-coating the coating composition (1) obtained in Preparation Example 1 on a substrate, the substrate was dried at 120 ° C. for 10 minutes and then baked at 250 ° C. for 60 minutes to form a primer layer having a thickness of 10 μm.
Next, a fluororesin (V) is applied on the primer layer by electrostatic powder coating, baked at 350 ° C. for 60 minutes, and further coated with a fluororesin (V) at 350 ° C. for 60 minutes. An intermediate layer having a thickness of 100 μm was formed by baking.
Finally, fluororesin (IV) was applied by electrostatic powder coating, and baked at 350 ° C. for 60 minutes to form a 50 μm top coat layer.

Corrosion resistance and adhesion test:
Test pieces were obtained from the obtained film body (three-layer film body) having the three-layer film, and tested for corrosion resistance and adhesion. The results are shown in Table 2.

(Example 2)
A three-layer coating was prepared in the same manner as in Example 1 except that the coating composition (2) was used in place of the coating composition (1), and the corrosion resistance and adhesion strength tests were conducted. The results are shown in Table 2.

(Example 3)
In Example 2, a three-layer coating was prepared in the same manner except that the firing temperature for forming the primer layer was changed from 250 ° C. to 350 ° C., and the corrosion resistance and adhesion strength were tested. The results are shown in Table 2.

Example 4
In Example 1, the coating composition (3) is used in place of the coating composition (1), and the three-layer coating is similarly used except that the firing temperature when forming the primer layer is changed from 250 ° C to 300 ° C. Were prepared and tested for corrosion resistance and adhesion. The results are shown in Table 2.

(Example 5)
In Example 1, the coating composition (4) was used instead of the coating composition (1), and the firing temperature when forming the primer layer was changed from 250 ° C to 300 ° C. Were prepared and tested for corrosion resistance and adhesion. The results are shown in Table 2.

(Comparative Example 1)
A three-layer coating was prepared in the same manner as in Example 1 except that the coating composition (5) was used in place of the coating composition (1), and the corrosion resistance and adhesion strength were tested. The results are shown in Table 2.

(Comparative Example 2)
In Example 1, instead of the coating composition (1), a primer 850-7799 (manufactured by DuPont) using a mixture of chromic acid and phosphoric acid was mixed with 850N-314 (manufactured by DuPont) at a ratio of 1: 3. A three-layer coating was prepared in the same manner except that the mixed composition was used as a primer composition, and the corrosion resistance and adhesion were tested. The results are shown in Table 2.

(Preparation Example 2)
Coating compositions (6) to (10) were prepared by mixing the fluororesin aqueous dispersion, the reactive functional group-containing fluororesin shown in Table 3, an organic titanate, a thickener, and water. In Table 3, the unit of the amount of each component is parts by weight.

(Example 6)
Preparation of three-layer coating:
The substrate was shot blasted with # 60 alumina using SUS304. After spray-coating the coating composition (7) obtained in Preparation Example 2 on a substrate, the substrate was dried at 120 ° C. for 10 minutes and then baked at 250 ° C. for 60 minutes to form a primer layer having a thickness of 10 μm.
Next, a fluororesin (V) is applied on the primer layer by electrostatic powder coating, baked at 350 ° C. for 60 minutes, and further coated with a fluororesin (V) at 350 ° C. for 60 minutes. An intermediate layer having a thickness of 100 μm was formed by baking.
Finally, fluororesin (IV) was applied by electrostatic powder coating, and baked at 350 ° C. for 60 minutes to form a 50 μm top coat layer.

Corrosion resistance and adhesion test:
A test piece was obtained from the obtained three-layer coating and tested for corrosion resistance and adhesion. The results are shown in Table 4.

(Examples 7 to 10)
In Example 6, instead of the coating composition (7), a three-layer coating was prepared in the same manner except that the coating compositions (6) and (8) to (10) were used, respectively. A test was conducted. The results are shown in Table 4.

(Example 11)
Preparation of bilayer coating:
The substrate was shot blasted with # 60 alumina using SUS304. After spray-coating the coating composition (9) obtained in Preparation Example 2 on a substrate, the substrate was dried at 120 ° C. for 10 minutes and then baked at 250 ° C. for 60 minutes to form a primer layer having a thickness of 10 μm.
Next, fluororesin (IV) was finally applied by electrostatic powder coating, and baked at 350 ° C. for 60 minutes to form a 50 μm topcoat layer.

Corrosion resistance and adhesion test:
A test piece was obtained from the obtained two-layer coating and tested for corrosion resistance and adhesion. Corrosion resistance was evaluated in terms of the ratio of the defect occurrence area to the test area for the test piece (4) after 4 weeks of corrosion resistance in the above test method. The results are shown in Table 5.

(Examples 12 to 15)
In Example 11, (7) obtained in Preparation Example 2 was used instead of the coating composition (9), and the fluororesin (IV) used to form the topcoat layer was replaced with the fluororesin (V), respectively. Except for substituting (VIII), a two-layered film was obtained in the same manner, and corrosion resistance and adhesion tests were conducted. The results are shown in Table 5.

(Example 16)
In Example 11, a two-layer coating was obtained in the same manner except that the coating composition (7) obtained in Preparation Example 2 was used in place of the coating composition (9), and the corrosion resistance and adhesion were tested. It was. The results are shown in Table 5.

(Example 17)
In Example 11, a two-layer coating was obtained in the same manner except that the coating composition (6) obtained in Preparation Example 2 was used in place of the coating composition (9), and the corrosion resistance and adhesion strength were tested. It was. The results are shown in Table 5.

(Example 18)
Preparation of bilayer coating:
The substrate was shot blasted with # 60 alumina using SUS304. After spray-coating the coating composition (7) obtained in Preparation Example 2 on a substrate, the substrate was dried at 120 ° C. for 10 minutes and then baked at 250 ° C. for 60 minutes to form a primer layer having a thickness of 10 μm.
Next, the fluororesin (VII) is applied on the primer layer by electrostatic powder coating, baked at 350 ° C. for 60 minutes, and further coated with the fluororesin (VII) at 350 ° C. for 60 minutes. A top coat layer having a thickness of 50 μm was formed by baking.

Steam exposure test:
The obtained film body (two-layer film body) having a two-layer film was exposed to steam at 120 ° C. for 60 minutes in an autoclave, and the adhesion after the exposure was evaluated by a drawing test (JIS K6894). Evaluation was performed before exposure and after 1-5 exposures. Evaluation was carried out by a method of evaluation in five stages from 1 (bad) to 5 (good) as defined in JIS K6894. The results are shown in Table 6.

(Comparative Example 3)
In Example 18, a two-layer coating was prepared in the same manner except that the coating composition (5) obtained in Preparation Example 2 was used instead of the coating composition (7), and a steam exposure test was performed. . The results are shown in Table 6.

(Comparative Example 4)
In Example 18, instead of the coating composition (7), a primer 850-7799 (manufactured by DuPont) using a mixture of chromic acid and phosphoric acid was mixed with 850N-321 (manufactured by DuPont) at a ratio of 1: 3. A two-layer coating was prepared in the same manner except that the mixed composition was used as a primer composition, and a steam exposure test was conducted. The results are shown in Table 6.

  As described above, a primer composition comprising a fluororesin having an MFR of 30-40 g / 10 min as the primer composition (Example 1), and a fluororesin having an MFR of 30-40 g / 10 min and a functional group-containing fluororesin The product used as a product (Example 6) exhibited performance superior to that of a primer using a mixture of chromic acid and phosphoric acid (Comparative Example 2), and also in other Examples, chromic acid and phosphorus were used. It turns out that the performance comparable as the primer (comparative example 2) using the mixture of an acid is exhibited.

In addition, when the organic titanate contained in the coating composition of the present invention is used as a water-soluble coating, it must be stable to some extent in water, or should not affect the adhesion even when decomposed. Even if the coating composition containing the organic titanate used in the examples of the present invention was used as a one-component coating, there was no problem in the adhesion and corrosion resistance performance even after refrigerated storage for 1 year and standing at room temperature for 3 months. Therefore, it can be sufficiently used as a one-component paint.

The coating composition provided by the present invention and the film body using the coating composition exhibit good adhesion to metals, ceramics, glass, heat-resistant plastics and the like despite containing a fluororesin.
Moreover, since the component which contributes to adhesiveness with base materials, such as a metal, contains organic titanate with a strong inorganic character, the problem that solvent resistance, high temperature resistance, and abrasion resistance are inferior does not arise.
Furthermore, a primer layer is formed by containing a polyphenylene sulfide resin in a film containing a fluororesin that is sequentially laminated on the coating film containing a fluororesin and an organic titanate formed on the substrate as a primer layer. The overall resistance can be greatly increased.
The coated body provided by the present invention does not cause a problem that it is inferior in solvent resistance or high temperature resistance as compared with a conventional method in which an organic resin having adhesion to a metal or glass is added to a fluororesin. . Moreover, compared with the conventional film body which contains the mixture of chromic acid and phosphoric acid in a fluororesin, it becomes possible to reduce the burden on an environment.

Claims (14)

  Containing a fluorine resin and an organic titanate having a melt flow rate (MFR) of 10 to 100 g / 10 min measured at 372 ° C. according to ASTM D1238, and containing titanium contained in the organic titanate with respect to the fluororesin A coating composition characterized in that the amount is from 1 to 40% by weight.   Alkoxy titanium, titanium acylate or titanium having a structure in which the organic titanate includes Ti—IV bond formed by Ti (IV) or Ti (III) and a compound having an alcoholic hydroxyl group, a phenolic hydroxyl group or a carboxyl group The coating composition according to claim 1, which is a chelate.   The coating composition according to claim 2, wherein the organic titanate is titanium diisopropoxybis (triethanolaminate).   The fluororesin is a polymer of a monomer selected from tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, fluoroalkoxytrifluoroethylene, vinylidene fluoride and vinyl fluoride, or a copolymer of these monomers and ethylene. Or the coating composition in any one of Claims 1-3 which is a copolymer of the compound which has a reactive functional group, and a fluorine-containing comonomer. The fluororesin is tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), ethylene / tetrafluoroethylene copolymer (ETFE), polychlorotri The coating composition according to claim 4, which is at least one selected from fluoroethylene (CTFE) and polyvinylidene fluoride (PVDF).   The composition further comprises a reactive functional group-containing fluororesin that is a tetrafluoroethylene / reactive functional group-containing compound / fluorine-containing comonomer copolymer in a proportion of 0 to 99% by weight with respect to the fluororesin. The coating composition according to any one of claims 1 to 5, which is contained.   The coating composition according to claim 6, wherein the compound having a reactive functional group is a trifluorovinyl ether group-containing phosphate compound. The coating composition according to claim 7, wherein the trifluorovinyl ether group-containing phosphate compound is a dihydrogen phosphate compound represented by the following formula (3).
CF ₂ = CF (OR) _m (CH ₂ ) OP (O) (OH) ₂ (3)
(In the formula, R represents a perfluoroalkyl group or a perfluoroalkoxy group having 1 to 20 carbon atoms, and m is an integer of 1 to 10. When m is 2 or more, each R is the same. Or different.)   The coating composition according to any one of claims 5 to 8, wherein the fluororesin-containing comonomer is perfluoro (alkyl vinyl ether) or perfluoro (alkyl vinyl).   The manufacturing method of the coating body which apply | coats the coating composition in any one of Claims 1-9 on a base material, removes a liquid solvent, and baked then and forms a film.   The average thickness of the film formed on the base material is 1 to 300 µm, The film body manufactured by the method according to claim 10.   A film body comprising a structure in which the film according to claim 11 is used as a primer layer, and a layer of fluororesin or a layer mainly composed of fluororesin is formed on the primer with an average thickness of 2 to 5000 μm.   The film body according to claim 12, comprising a layer containing a fluororesin and a polyphenylene sulfide resin as an intermediate layer between the primer layer and the outermost layer.   The coated body according to claim 11 or 12, wherein the substrate is any one of metal, ceramic, stainless steel, glass, heat resistant plastic, and the like.