JP2910863B2 - Super durable laminate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a super-durable laminate, and more specifically, a powder paint layer and a fluororesin paint layer are sequentially laminated on a metal substrate, and the interlayer adhesion is remarkably improved. The present invention relates to a super-durable laminate which can exhibit characteristics based on a powder coating material and characteristics by a fluororesin overcoat layer sufficiently.

Prior art Fluorine resin-based topcoats provide coatings with excellent weather resistance and corrosion resistance, but due to poor adhesion to the ground or the base coating, epoxy resin with good adhesion to the base and good workability A multilayer coating film which is used as a primer and on which a fluororesin paint is applied is widely used as a color steel plate for roofing materials and the like. However, the conventional epoxy primer is used as a solvent type paint and its film thickness is about 5μm. Therefore, if it is damaged during transportation or construction of the coated product, the damage easily reaches the base material. It has often been a problem that the corrosion resistance is significantly impaired. It was difficult to apply a solvent-type epoxy primer paint thickly from the viewpoint of workability such as cracking and sagging.

On the other hand, powder coatings are generally capable of thick coating, but the adhesion between the fluororesin coating and the powder coating is poor. Not practical.

Under such circumstances, the present inventors have previously used a powder coating comprising a combination of a specific epoxy resin, ie, a bisphenol A type epoxy resin, and a specific curing agent, ie, a phenolic curing agent, to thereby form a fluororesin coating layer. It was found that the adhesiveness to the material was greatly improved, and a patent application was filed as Japanese Patent Application No. 62-196133 (Japanese Patent Application Laid-Open No. 40-40329). The invention according to the above application provides a thick primer layer of an epoxy resin having relatively good workability on a metal substrate, and a fluorine-based overcoat layer having excellent coating performance on the primer layer. Since it can be received even with excellent adhesion, it can be provided with a laminate coating plate that is extremely useful in roofing materials and fields requiring heavy anticorrosion function. However, this method has a problem that it is limited to a specific epoxy resin and a specific curing agent, and only a matte coating film can be obtained.

Problems to be Solved by the Invention Therefore, without using a specific powder coating, any powder coating having different characteristics can be selected and used according to the application, and the characteristics of the fluororesin coating can be sufficiently exhibited. Therefore, a fluorine-based coating layer is provided on the powder coating layer,
There is a demand for a super-durable laminate having a particularly improved interlayer adhesion, and it is an object of the present invention to meet such a problem. It is another object of the present invention to provide a super-durable laminate having particularly improved workability, corrosion resistance and weather resistance.

Means for Solving the Problems According to the present invention, the object of the invention has a primer layer for powder coating or has no metal substrate, a powder coating layer and a fluororesin coating layer are sequentially laminated. In the laminate, the powder coating layer, the base material powder particles are a room-temperature solid heat-fusible film-forming binder resin, the average particle diameter obtained as an essential component of methyl methacrylate monomer 0.001 ~ 10μm A resin powder obtained by adding a resin fine particle of the above to the composite powder coating in a solid content weight ratio of 0.05 to 40% by weight in the composite powder coating and baking the powder. This is achieved by a super-durable laminate characterized by being a body paint layer.

In the present invention, a steel plate, a galvanized steel plate, an aluminum / galvanized steel plate, an aluminum plate, a stainless steel plate or any other metal plate having a primer layer for powder coating in advance or a metal plate itself without a primer layer A substrate is used.

As a primer, any primer for powder coating such as polyester resin, epoxy resin, acrylic resin,
A urethane resin or the like is preferably used, but is not particularly limited.

The powder coating for coating on the metal substrate surface with or without the primer layer, the base material powder particles which are a room-temperature solid heat-fusible film-forming binder resin, methyl methacrylate as an essential component of the monomer A resin particle obtained by adding fine resin particles having a particle diameter of 0.001 to 10 μm is used. Here, the addition ratio of the resin fine particles is 0.05 to 40% by weight, preferably 0.1 to 20% by content in the composite powder coating.

When the average particle size of the resin fine particles is small, the addition amount may be small, but the lower limit of the particles is about 0.
It is about 001 μm. With this particle size, about 0.05% by weight is required for the effect to be exhibited by addition. When the particle size exceeds 10 μm, the adhesion to the top coat will not be sufficient unless the addition amount is increased to a ratio exceeding 40% by weight. If the content exceeds% by weight, the appearance of the coating film is adversely affected. Here, as the binder resin constituting the base powder particles, an acrylic resin, a polyester resin, an epoxy resin, or the like which is solid at normal temperature and melts by heating to form a film can be used without any problem. These do not hinder the addition of commonly used pigments, curing agents and other additives. The average particle diameter of the base powder particles is
Although not particularly limited, those having a thickness of about 30 to 50 μm are suitable from the viewpoint of the coating work, the state of the coating film surface, and the like.

Next, the resin fine particles obtained by using methyl methacrylate as an essential component can be composed of any resin, but from the viewpoint of production or practical use, vinyl resin (including acrylic resin), epoxy resin, polyester resin, melamine It is preferably a resin or the like, and particularly preferably a vinyl resin in terms of ease of production and a large degree of freedom in design. That is, there may be mentioned those obtained by directly polymerizing a vinyl monomer by emulsion polymerization or suspension polymerization, and those obtained by pulverizing and classifying a resin by solution polymerization, bulk polymerization or the like.

The resin fine particles may be crosslinked or non-crosslinked, and the shape thereof may be any of particulate, fibrous, plate-like, and is not particularly limited. When preparing vinyl resin particles which are practically easy to produce, the vinyl monomers may be 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
-Hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, glycidyl (meth) acrylate, β- Methyl glycidyl (meth) acrylate, N-glycidyl acrylamide, glycidyl vinyl sulfonate, (methyl) glycidyl ether of allyl alcohol and the like are used alone or in combination of two or more. In addition to these, as monomers used in combination with these, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, (meth)
Cyclohexyl acrylate, (meth) acrylic acid-2-
Ethylhexyl, octyl (meth) acrylate, 2-ethyloctyl (meth) acrylate, dodecyl (meth) acrylate, benzyl (meth) acrylate, (meth)
Phenyl acrylate, dialkyl fumarate, dialkyl itaconate, styrene, (meth) acrylonitrile, vinyltoluene, α-methylstyrene,
(Meth) acrylamide, methylol (meth) acrylamide, vinyl acetate, vinyl propionate, lauryl vinyl ether, halogen-containing vinyl monomers and the like are also included.

The average particle size of the resin fine particles thus obtained is not required to be so strict as long as it is smaller than the particle size of the base powder particles used for the powder coating layer, but for the reasons described above, 0.001 to 10 μm Preferably, those having a range of 0.01 to 5 μm are used.

Although the resin fine particles obtained here were obtained using methyl methacrylate as an essential component of the monomer, there is no need to particularly limit the usage ratio to the total amount of all components, and the binder resin constituting the base powder particles The nature of the
It is good to consider the easiness of addition work, etc., but it is usually preferable to use the MMA in which the ratio of use to the total amount of all the components is 10 to 100% in the resin fine particles in terms of solid weight ratio. .

In the present invention, the above-mentioned resin fine particles are contained in such powder particles.However, as long as the resin fine particles are present on at least the surface of the base powder particles, the resin fine particles may be added in any step of the base powder particle manufacturing process. Can be. However, it is preferable to add the resin fine particles to the base powder particles in order to maintain the solid state of the resin fine particles and to assure that the resin fine particles are present on the surface of the base powder particles.

In order to add the resin fine particles to the base powder particles, for example, a resin as a raw material of the powder is mixed with a coloring agent and a curing agent which are added as needed, and then melt-kneaded. Mixing method using a mixer, Henschel mixer, etc., mixing powder obtained by wet dispersion from resin as powder raw material and resin fine particles with a hybridizer, a ball mill, etc., and mixing resin particles as powder raw material with resin There is a method of coating with fine particles and forming a continuous film. Therefore, in the present invention, "including" resin fine particles includes both of the above-mentioned embodiments.
However, the present invention is not limited at all by these production methods, for example, melting of the powder, using a relatively large amount of resin fine particles in the granulation step to allow the resin particles to be present at least on the surface of the powder particles, It is, of course, possible to use a combination of methods, and the form of mixing of the paint for the obtained powder coating layer changes depending on the method of addition, but the present invention is not limited thereby.

The thus-obtained coating material for the powder coating layer is applied to the surface of the metal substrate by a commonly used method, and then the fluororesin is applied.

As described above, the adhesion between the fluororesin and the powder coating layer is not good. Particularly, in the case of the vinylidene fluoride type fluororesin, the adhesion between the fluororesin and the powder layer is extremely poor because the fluororesin does not have an adhesion functional group. However, when the powder coating of the present invention is used, the adhesion between the fluororesin and the powder coating layer is extremely good, so that a fluorine resin coating with high durability can be applied.

Hereinafter, the features of the present invention will be specifically described by describing Examples and Comparative Examples.

Reference Example 1 (Synthesis of Resin Fine Particles A) A reaction vessel equipped with a stirrer, a cooler and a temperature controller was charged with 380 parts of deionized water and 2 parts of nonionic surfactant MON2 (manufactured by Sanyo Chemical Co., Ltd.). Dissolve the mixture while maintaining the stirring temperature at 80 ° C., and add a solution obtained by dissolving 1 part of an initiator: ammonium persulfate in 10 parts of deionized water.

Then 61 parts of methyl methacrylate, 36 parts of styrene, n
-A mixed solution consisting of 3 parts of butyl methacrylate is added dropwise over 60 minutes. After the addition, stirring is continued at 80 ° C. for 60 minutes.

Thus, an emulsion having a nonvolatile content of 20% and a particle size of 0.03 to 0.05 μ is obtained. This emulsion was spray-dried to obtain resin fine particles A.

Reference Example 2 (Synthesis of Resin Fine Particles C) A reaction vessel equipped with a stirrer, a cooler, and a temperature controller was charged with 380 parts of deionized water and 2 parts of a nonionic surfactant MON2 (manufactured by Sanyo Chemical Co., Ltd.). Dissolve the mixture while maintaining the stirring temperature at 80 ° C., and add a solution obtained by dissolving 1 part of an initiator: ammonium persulfate in 10 parts of deionized water.

Then, methyl methacrylate 90 parts, styrene 33 parts, n
A mixed solution comprising 46 parts of -butyl methacrylate and 20 parts of 2-hydroxyethyl methacrylate is added dropwise over 60 minutes. After the addition, stirring is continued at 80 ° C. for 60 minutes.

Thus, an emulsion having a nonvolatile content of 20% and a particle size of 0.03 to 0.05 μm is obtained. The emulsion was spray-dried to obtain fine resin particles B.

Reference Example 3 (Synthesis of Resin Fine Particles B) A reaction vessel equipped with a stirrer, a cooler, and a temperature controller was charged with 380 parts of deionized water and 2 parts of a nonionic surfactant MON2 (manufactured by Sanyo Chemical Co., Ltd.). Dissolve the mixture while maintaining the stirring temperature at 80 ° C., and add a solution obtained by dissolving 1 part of an initiator: ammonium persulfate in 10 parts of deionized water.

Then, a mixed solution comprising 3 parts of lauryl methacrylate, 15 parts of methyl methacrylate and 82 parts of styrene is added dropwise over 60 minutes. After the addition, stirring is continued at 80 ° C. for 60 minutes.

Thus, an emulsion having a nonvolatile content of 20% and a particle size of 0.03 to 0.05 μm is obtained. The emulsion was spray-dried to obtain fine resin particles C.

Reference Example 4 (Preparation of ground resin particles D) A flask equipped with a dropping funnel, a stirring blade, and a thermometer was charged with 80 parts by weight of xylene and heated to 130 ° C. Using a dropping funnel, a solution of 36 parts of methyl methacrylate, 10 parts of styrene, 24 parts of glycidyl methacrylate, 30 parts of tert-butyl methacrylate, and 6 parts of initiator Kayaester O was dropped at a constant rate into the flask over 3 hours. After holding for 30 minutes after completion of the dropping, 20 parts of xylene and 1 part of Kayaester O were dropped at a constant speed for 1 hour using a dropping funnel. After completion of the dropwise addition, the mixture was kept at 130 ° C. for 2 hours, and then xylene was removed by distillation under reduced pressure to obtain an acrylic resin.

The synthesized acrylic resin was pulverized by a pulverizer to an average particle size of about 30 μ to obtain non-crosslinked resin particles D.

Reference Example 5 (Preparation of epoxy paint E) Epotote YD-019 (Epoxy resin manufactured by Toto Kasei) 100
Parts by weight, 3 parts of dicyandiamide and 40 parts of titanium oxide CR50 are dry-mixed with a Henschel mixer (manufactured by Mitsui Miike Seisakusho), and then a co-kneader PR-46 (Switzerland: Buss).
After cooling, the mixture was cooled at a temperature of 100 ° C., cooled, pulverized with a hammer mill, and classified with a 150-mesh wire net to obtain powder particles E.

Reference Example 6 (Preparation of polyester paint F) ER6800 (Polyester resin manufactured by Nippon Polyester) 10
0 parts by weight, 36 parts of Cleran UI (block isocyanate manufactured by BASF) and 40 parts of titanium oxide CR50 are dry-mixed using a Henschel mixer (manufactured by Mitsui Miike Seisakusho), and then a co-kneader PR-46 (made by Buss, Switzerland). The mixture was cooled and melted at a temperature of 100 ° C., cooled, pulverized by a hammer mill, and classified by a 150-mesh wire net to obtain powder particles F.

Example 1 To 99.95 parts of the powder particles E of the base material obtained in Reference Example 5, 0.05 part of resin fine particles A was added and dry-mixed with a Henschel mixer for 30 seconds to obtain a composite powder coating.

After electrostatically applying the composite powder paint thus obtained, 180
Bake at 20 ° C. for 20 minutes to prepare a 80 micron (μm) coating.

Fluorine paint (Duraner C Nippon Paint Co., Ltd.) was applied on this with a bar coater, and baked at 270 ° C for 1 minute to obtain 20
A micron (μm) coating was prepared.

Table 1 shows the results of evaluation of the thus obtained appearance and the interlayer adhesion between the fluorine coating and the appearance (smoothness).
All have good results.

Examples 2 to 8 In accordance with the method of Example 1, preparation of a composite paint and preparation of a coating film thereof were carried out with the composition shown in Table 1, and the resulting appearance, interlayer adhesion and appearance (smoothness) of the fluorine coating film were obtained. ) Are shown in Table 1, and all good results have been obtained.

Comparative Example 1 A composite powder coating material was obtained in the same manner as in Example 1 except that the type of the resin fine particles was changed to A, with the composition shown in Table 1.

Table 1 shows the results of evaluation of the appearance thus formed and the interlayer adhesion between the fluorine coating film. The adhesion to the fluorine coating film was poor.

Comparative Examples 2 to 4 In accordance with the method of Comparative Example 1, preparation of a composite paint and preparation of a coating film thereof were carried out with the formulation shown in Table 1, and the resulting appearance, interlayer adhesion and appearance (smoothness) with a fluorine coating film were obtained. Table 1 shows the results of the evaluation of (1), however, the smoothness was poor.

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Claims (4)

(57) [Claims] 1. A laminate comprising a powder coating layer and a fluororesin coating layer sequentially laminated on a metal substrate having or not having a powder coating primer layer, wherein the powder coating layer is An average particle size obtained by using methyl methacrylate as an essential component of the monomer in the mother powder particles, which is a film-forming binder resin capable of being heated and melted at room temperature solid, is 0.001 to 10 μm.
m resin fine particles in the composite powder coating in a solid content weight ratio.
A super-durable laminate characterized by being a powder coating layer obtained by applying a composite powder coating obtained by adding so as to have a ratio of 0.05 to 40% by weight and baking. 2. The laminate according to claim 1, wherein the binder resin is selected from the group consisting of an acrylic resin, a polyester resin, and an epoxy resin. 3. The laminate according to claim 1, wherein the fluororesin is a vinylidene fluoride polymer. 4. The laminate according to claim 1, wherein the primer layer is a resin primer layer selected from the group consisting of polyester resin, epoxy resin, acrylic resin, and urethane resin.