JPS6227469A - Fluororesin paint composition - Google Patents

Abstract

PURPOSE:To obtain a fluororesin paint compsn. which can be applied to metallic sheets and gives a coating film having improved physical properties, by adding a silane coupling agent or a titanate coupling agent to a fluororesin. CONSTITUTION:A paint compsn. is obtd. by using a fluororesin as main component and incorporating 0.01-10pts.wt. silane coupling agent and/or titanate coupling agent in 100pts.wt. epoxy resin. IF desired, thermoplastic resin such as acrylic resin, thermosetting acrylic resin, isocyanate compd., color pigment, extender pigment, plasticizer, org. solvent, surfactant, anti-foaming agent, etc. may be added. An example of the titanate coupling agent is isopropyltriisostearoyl titanate. An example of the silane coupling agent is vinyltrichlorosilane.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fluororesin coating composition, and particularly to a fluororesin coating composition coated on a metal plate with improved coating film properties.

Prior Art Various metal plates, such as galvanized steel plates, AI! -Zn
Alloy-plated mesh plates, stainless steel plates, aluminum plates, etc. are used in a variety of fields, but applying fluororesin paint to these metal plates improves their outdoor weather resistance, bending workability, chemical resistance, and solvent resistance. Metal plates coated with fluororesin coatings are used in various fields because of their improved physical properties such as abrasion resistance.

In particular, it is used as an ultra-durable protective film for colored steel plates used in the construction material field.

By the way, in order to paint, for example, a galvanized steel plate or a 7-metal steel plate with a fluororesin paint, the surface of the steel plate is first treated with phosphate or chromate and dried to remove rust etc. on the surface and to perform rust prevention treatment. Next, since fluororesin coatings do not have good adhesion to metals, an undercoat with an epoxy resin as the skeleton base resin is applied to the surface treated surface to a dry film thickness of 3 to 12 μm. Metal surface temperature is 1
Baking is dried at a temperature of 60°C to 220°C. Next, a fluororesin paint is applied so that the dry film thickness is 15 to 35 μm, and then baked and dried so that the metal surface temperature is 220 to 260°C. In this way, an undercoat and a fluororesin paint are used in combination, and these undercoat and topcoat are each applied, for example, by a roll coating method, and then baked to dry. Temporary is obtained.

However, during the baking process of this fluororesin coating, there are areas where the coating film is not formed on the edge of the steel plate in a width range of 0.1 to 51mm. , which causes the undercoat film to be exposed. If there are areas that are not covered with such a fluororesin coating, it will not only be unfavorable in terms of appearance as a metal-coated plate, but more importantly, rust will easily occur from the areas that are not covered with the fluororesin, and the undercoat will deteriorate. The paint film is prone to cracking, which shortens its useful life as a building material. Therefore, the parts that are not covered by the fluororesin coating are repaired by installing steel plates in designated parts of the building and then manually applying other paints such as thermoplastic acrylic lacquer. required a huge amount of expense.

This phenomenon occurs when the paint film applied at the paint application stage is baked and dried, and the undercoat film is exposed without being covered by the paint film. Because of its poor solubility in solvents, it is used as a so-called solvent-type dispersion organ nodule, in which fluororesin is dispersed in a solvent. This is thought to be due to the fact that the coating film shrinks during this process. The reason for this shrinkage is that the fluororesin is a crystalline thermoplastic resin, so it is thought that it melts to form a continuous film and crystallizes when it is cooled. It is thought that the stronger the force, the more likely the coating film will shrink.

This phenomenon in which the undercoat film is exposed due to shrinkage of the fluororesin paint film is not limited to the edges of the metal plate, but can also be caused by scratches on the roll surface, bubbles formed in the paint, or paint when applying the fluororesin paint by roll. Baking also occurs when a uniform coating film is not formed on the surface of the metal plate due to foreign matter mixed in with the metal plate, and when the uneven coating film cracks during drying.

This cracking is also caused by crystallization of the polymer during the film-forming process in which the applied fluororesin particles are melted to form a continuous film as described above. Generally, a high boiling point solvent with a slow evaporation rate is used as the organic solvent, or a large amount of plasticizer is added to the organic solvent. However, increasing the amount of high-boiling solvents or plasticizers may cause the paint to exhibit strong thixotropic behavior, impairing its suitability for painting, or the residual plasticizer may seep out of the paint film, causing dirt to form and stain the paint. (This has the drawback of causing paint film defects such as softening of the paint film and softening of the paint film.

Problems to be Solved by the Invention As mentioned above, with conventional fluororesin paints, the paint film on the metal plate exposes the undercoat film at the edges, and cracks occur in uneven paint film areas. There were some problems, and improvements were desired.

Means for Solving the Problems In order to solve the above problems, the present invention combines a fluororesin and one or more of each or both of a silane coupling agent and a titanate coupling agent into a fluororesin 100% The object of the present invention is to provide a fluororesin coating composition characterized in that it contains 0.01 to 10 parts by weight.

Next, the present invention will be explained in detail.

The fluororesin coating composition of the present invention has a fluororesin as a main component, and one or more of each or both of a silane coupling agent and a titanate coupling agent is added to the fluororesin in an amount of 0% per 100 parts by weight of the fluororesin. .01 to 10 parts by weight is an essential component, but further components other than these include thermoplastic resins such as acrylic resins, thermosetting acrylic resins, melamine resins, urea resins, isocyanate compounds, coloring pigments, Additives commonly used in paints, such as extender pigments, plasticizers, organic solvents, surfactants, and antifoaming agents, can also be used alone or in combination of two or more.

In the present invention, examples of fluororesins include tetrafluoroethylene (CFz=CFz), chlorotrifluoroethylene (CI?2=CFCβ), hexafluoropropylene (CF:1-CF=CF2), and trifluoroethylene (CIIF=CF2). ), vinyl fluoride (C1lz=CH
F) All fluorine-containing polymers obtained by homopolymerization of fluorine-containing polymers such as hyphrovinylidene (CF, = CI + □) or copolymerization with other monomers are included. Examples include polyvinylidene fluoride and polyvinyl fluoride.

Examples of the thermoplastic acrylic resin include polymers of acrylic esters and methacrylic esters, and copolymers thereof. In this case, the ester groups include methyl, ethyl, propyl, butyl, isobutyl, n-
Examples include hexyl, lauryl, stearyl and the like. The copolymer may contain one or more of these ester groups.

Thermosetting acrylic resins contain functional groups (carboxyl groups, hydroxyl groups, amino groups,
methylol group, epoxy group, etc.), such as acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-methylol acrylamide, allyl glycidyl ether, glycidyl methacrylate;
Examples include, but are not limited to, polymers obtained by copolymerizing two or more monomers selected from two groups of styrene, acrylic esters, and methacrylic esters.

In the present invention, as the thicnate coupling agent, isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate,
Isopropyl tris (dioctyl pyrophosphate)
Titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite l-) titanate, tetra(2,2-diallyloxymethyl-1-butyl) bis(di-tridecyl) phosphite titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene natanate, isopropyl trioctanoyl titanate, isopropyl dimethacrylylisostearoyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl trictinate Milphenyl titanate, isopropyltri(N-aminoethyl-aminoethyl)titanate, dicumylphenyloxyacetate titanate, diisostearoylethylenenathanate, and the like.

In addition, as a silane coupling agent, vinyltrichlorosilane, vinyltris I-quinsilane, γ-chloropropyltrimethoxysilane, γ-chloropropylmethyldichlorosilane, T-chloropropylmethyldimethoxysilane, T-chloropropylmethyljethoxysilane ,
γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyl 1-rimethoxysilane, N-(β-aminoethyl-γ-aminopropylmethyldimethoxysilane, γ-mercap 1-propyltrimethoxy Silane, T-glycidoxypropyltrimethoxysilane, T-glycidoxypropylmethyldimethoxysilane, T-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, vinyltris(β-methoxyethoxy)silane ,
β-(3,4-Eboxycyclohexol)-ethyltrino! -Xysilane and the like.

The coating composition of the present invention contains, based on 100 parts by weight of fluororesin,
Although it contains 0.01 to 10 parts by weight of one or more titanate coupling agents or silane coupling agents, it is effective in improving (preventing) the shrinkage of the coating film during the melt coating process of fluororesin. It is preferably 0.1 parts by weight or more, and particularly preferably 0.3 to 2.0 parts by weight since there is no noticeable difference in effects when it is 5 parts by weight or more.

The coating composition of the present invention contains the above-mentioned fluororesin, titanate coupling agent, or silane coupling agent as essential components, but considering its coating suitability, when using polyvinylidene fluoride resin as the fluororesin, for example, It is preferable to add 10 to 60 parts by weight of thermoplastic resin or thermosetting acrylic resin per 100 parts by weight.

At this time, various plasticizers may be added to maintain appropriate fluidity of the paint.

Furthermore, when the composition of the present invention is supplied as a solvent-based dispersion organo-nodule paint, a solvent is added, and the composition of this solvent is determined by the dispersion of the fluororesin, the viscosity and flow characteristics of the paint, and the long-term properties of the paint. It has a large influence on the storage stability of the paint, which indicates storage stability (the property that resin particles are stably dispersed in a dispersion medium and does not aggregate), and the coating film-forming ability, which indicates film-forming performance. Generally, a solvent having a polar group such as a ketone or ester solvent and an aromatic hydrocarbon solvent are used in combination.

As for the colorant that can be added to the coating composition of the present invention, any pigment can be used, but in order to take advantage of the properties of fluororesin such as heat resistance, chemical resistance, outdoor weather resistance, etc. It is preferable to use a pigment having specific properties, and when using it, for example, 5 to 240 parts by weight can be added to 100 parts by weight of vinylidene borifuff.

The coating composition of the present invention can be applied using a roll coating method, curtain=X
For the former two, paints using polyvinylidene fluoride or polyvinyl fluoride as the fluororesin are generally used, and for the spray painting method, paints using the above-mentioned tetrafluoroethylene, etc. alone or Copolymer paints are used.

The objects to be coated to which the paint of the present invention is applied are not limited to the above-mentioned metal plates on which fluororesin paints have conventionally been used, but also include other metals and other objects.

Example The present invention will be explained in detail below with reference to Examples.

Example 1 Thickness 0.6 ua, subjected to zinc phosphate chemical conversion treatment (surface treatment) on a two-coating, two-time baking type colored galvanized iron plate manufacturing line.
A coiled galvanized steel plate with a width of 9201 m was coated with No. 23 Primer (epoxy resin-based anti-rust undercoat paint: manufactured by Dainippon Ink & Chemicals) as an undercoat to a dry film thickness of 5 μm, and immediately the length was Baking drying was performed for 40 seconds in a 4010 undercoat drying oven so that the maximum metal surface temperature was 180°C. Next, polyvinylidene fluoride (Kaichi 500 = Benwall 14t!!
! 100 parts by weight, 0.5 parts by weight of titanium-based coupling agent (manufactured by Plen°7ct38S1 Ajinomoto C4@), P
Elbow A (acrylic resin manufactured by Dainippon Ink & Chemicals 0@) 16
Parts by weight, 70 parts by weight of titanium dioxide (Tie Bake CR-95, manufactured by Ishihara Sangyo 0'@), 40 parts by weight of isoboron, 25 parts by weight of methyl isobutyl ketone, 10 parts by weight of cellosolve acetate, and 30 parts by weight of toluene. The paint was roll coated to a dry film thickness of 20 μm, and immediately baked in a 50 m long top coat drying oven for 50 seconds at a maximum metal temperature of 260°C.

Example 2 In Example 1, titanate coupling agent 0.5
Silane coupling agent (TSL-83
A fluororesin paint was prepared in the same manner as in Example 1, except that 1.0 part by weight of 50 (manufactured by Toshiba Silicone Co., Ltd.) was used, and the coating was baked in the same manner as in Example 1.

Example 3 A fluororesin paint was prepared in the same manner as in Example 1 except that 1.0 parts by weight of a silane coupling agent (TSL-8350, manufactured by Toshiba Silicone Co., Ltd.) was further added to the fluororesin paint. Paint baking was performed in the same manner as in 1.

Comparative Example 1 In Example 1, 0.5 titanate camping agent
A fluororesin paint was prepared in the same manner except for the parts by weight, and the coating was baked in the same manner as in Example 1.

Evaluation tests were conducted on the coated steel plates obtained in Examples 1 to 3 and Comparative Example. The results are shown in the table.

In the table, the blistering evaluation of the paint film is based on ASTM D-714, and the bending workability (vise bendability) is based on the number of sheets that must be sandwiched in order to prevent the paint film from being scratched in the processed area. Indicated by (T is 0.6 thickness of one sheet) From the above test results, no exposed undercoat film was observed on the edges of the coated steel sheets using the paints of Examples 1 to 3. However, the painted steel plate of the comparative example had a coating of 0.5 on both edges.
Exposure of the undercoat film was observed in a continuous width of ~2.010 mm.

In addition, the coated steel plates using the paints of Examples 1 to 3 were found to have improved coating film blistering in the salt spray test, coating film blistering after boiling, and bending workability compared to those of the comparative examples. It is clear that these results not only indicate that exposure of the underlying layer due to cracking in non-uniform areas of conventional fluororesin coatings is less likely to occur, but also indicate further improvement in the physical properties of the coating.

In this way, the effects of titanate-based camping agents and silane coupling agents on fluororesins include effects related to dispersion stability in paints, which improves suitability for coating, and improvements in adhesion to the undercoat film.
It is thought that the effect on the physical properties of the coating film, such as a reinforcing effect on the fluororesin itself, is considered, but in any case, in addition to preventing shrinkage of the coating film, the physical properties of the metal coating coating film, such as salt spray resistance, boiling resistance, and bending resistance, are improved compared to fluororesin coating compositions.

As described in detail, according to the present invention, a fluororesin paint contains either a titanate coupling agent or a silane coupling agent, or both, and is applied to a metal plate and baked.・Even when drying is performed, the substrate will not be exposed at the edges of the metal plate due to shrinkage, and there will be no cracking that tends to occur in uneven areas of the coating, and it has excellent salt spray performance. Various physical properties of the coating film, such as boiling resistance and bending resistance, have been further improved, making full use of the characteristics of fluororesin, and providing coated panels with a long durable life. This can have a significant effect of reducing costs.

Claims (1)

[Claims] (1) A fluororesin and one or both of a silane coupling agent and a titanate coupling agent, or both.
0.01 to 1 or more seeds per 100 parts by weight of fluororesin
A fluororesin coating composition containing 0 parts by weight.