JP6874236B2 - Resin composition for coating - Google Patents

Description

The present invention relates to a coating resin composition.

Conventionally, industrial products using a resin base material have been widely used, although there are differences in the shapes of, for example, the housing of a personal computer and various films. What is common to these manufacturing methods is that the production line consistently performs from painting to drying. When the process from painting to drying is performed consistently on the production line as described above, the time required for the process is directly linked to productivity. Therefore, it is necessary to complete the above steps in a short time in order to improve productivity.

Examples of the method of drying in a short time include a method of using a one-component acrylic resin-based paint. However, as already recognized as basic technical information, although one-component paints can be dried in a relatively short time, the physical characteristics of the coating film such as adhesion and chemical resistance are not always sufficient. .. As a method for improving this point, for example, a two-component paint in which an acrylic resin and an isocyanate resin are reacted is known. In this case, although the coating material has good physical properties, the acrylic resin and the isocyanate resin are used when dried. Because it is necessary to react, the drying time is relatively long, and there is a problem of storage stability such as gelation due to the reaction proceeding before the paint is prepared and painted. Actual use was limited.

As a method of drying the two-component paint in a short time, there are a method of raising the drying temperature to a high temperature and a method of combining resins having relatively high reactivity. However, due to the problem of heat resistance of the resin base material, although there are differences depending on the material of the resin base material and the drying time, it is generally difficult to treat the resin base material at a high temperature. Therefore, in reality, the solution is to select the resin type used for the paint. As a resin type, for example, a combination of an epoxy resin and a curing agent such as an amine compound is widely known, but there is a trade-off relationship between quick-drying property and storage stability, and it is generally difficult to achieve both. is there. As a method for solving this problem, for example, a method of improving storage stability by covering the surface of the curing agent with fine particles (for example, Patent Documents 1 and 2) has been reported, but in this method, the fine particles are contained in the coating film. There is a problem that remains in the, and its range of use is limited. As another method, a method of modifying a novolak resin with a compound having an aminotriazine ring structure as a curing agent (for example, Patent Document 3) has been reported, but the structure of the curing agent is complicated and compatible with a solvent or epoxy. Since the type of resin is limited, the range of use thereof is limited.

JP-A-2015-203033 Japanese Unexamined Patent Publication No. 9-87364 JP-A-2002-226556

The present invention provides a coating resin composition having storage stability and quick-drying properties that can withstand use on a production line, and excellent coating film physical properties such as adhesion and chemical resistance of the coating film. The purpose.

As a result of diligent studies to solve the above problems, the present inventor has made a polyfunctional reactive compound having a specific number of epoxy groups and / or halohydrin groups and an amino resin having a specific number average molecular weight as essential components. The two-component epoxy resin composition containing the resin base material has excellent storage stability and quick-drying properties, and also has excellent coating property properties such as coating adhesion and chemical resistance, which are the characteristics of two-component paints. The present invention has been completed by finding that it is suitably used as a coating composition for coating on.

That is, the coating resin composition of the present invention is a composition for coating on a resin base material.
(A) A polyfunctional reactive compound having 2 to 15 epoxy groups and / or halohydrin groups in one molecule, and
(B) It is characterized by containing an amino resin having a number average molecular weight of 250 to 10,000.

In the coating resin composition of the present invention, the amino resin (B) is preferably a melamine resin.

In the coating resin composition of the present invention, the content of the component (B) is preferably 10 to 10,000 parts by weight with respect to 100 parts by weight of the component (A).

In the coating resin composition of the present invention, it is preferable that the (A) polyfunctional reactive compound has 2 to 10 epoxy groups and / or halohydrin groups in one molecule.

The member of the present invention is characterized by having a resin base material and a coating film formed on the resin base material using the coating resin composition of the present invention.

In the member of the present invention, the material of the resin base material is preferably polyester.

The method for manufacturing the member of the present invention is a method for manufacturing the member of the present invention.
The step (1) of applying the coating resin composition of the present invention to at least one surface of the resin base material, and
Step (2) of heating the coating resin composition applied in the step (1) at 60 to 250 ° C. for 5 to 300 seconds to cure it.
It is characterized by including.

Since the coating resin composition of the present invention contains a polyfunctional reactive compound having a specific number of epoxy groups and / or halohydrin groups and an amino resin having a specific number average molecular weight, it has excellent storage stability and quick-drying property. In addition to being excellent, it is also excellent in adhesion and chemical resistance of the coating film, and is suitably used as a coating composition for coating on a resin base material.

<< Resin composition for coating >>
The coating resin composition of the present invention is a composition for coating on a resin base material.
(A) A polyfunctional reactive compound having 2 to 15 epoxy groups and / or halohydrin groups in one molecule, and
(B) It is characterized by containing an amino resin having a number average molecular weight of 250 to 10,000.

<(A) Polyfunctional reactive compound>
The polyfunctional reactive compound (A) (hereinafter, also simply referred to as the component (A)) is not particularly limited as long as it has 2 to 15 epoxy groups and / or halohydrin groups in one molecule, and is a compound having an epoxy group. For example, sorbitol polyglycidyl ether, bisphenol A diglycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether, resorcinol diglycidyl ether, isosorbido diglycidyl ether, isomanni. Examples thereof include dodiglycidyl ether, isoidit diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, and cresol novolac polyglycidyl ether. Examples of the halohydrin compound include a compound obtained by reacting halogen and water with a compound having a double bond, and a compound obtained by reacting epihalohydrins with an alcohol compound in the presence of a Lewis acid catalyst (halohydrin). Ether compound) can be mentioned. For example, sorbitol polyhalohydrin, glycerin polyhalohydrin, diglycerin polychlorohydrin, ethylene glycol dihalohydrin, propylene glycol dichlorohydrin and the like can be mentioned. These may be used alone or in combination of two or more.

The number of epoxy groups and / or halohydrin groups contained in one molecule of the component (A) is not particularly limited as long as it is 2 to 15, but it is preferably 2 to 10 and preferably 2 to 6. Is more preferable, and 2 to 4 are further preferable. If the number of epoxy groups and / or halohydrin groups contained in one molecule of the component (A) is less than 2, the cross-linking reaction necessary for curing the resin composition to form a coating film is impossible. , If the number exceeds 15, the storage stability may decrease.

When the component (A) is an epoxy compound, the epoxy equivalent is not particularly limited, but is preferably 100 to 1000, and more preferably 120 to 700. If the epoxy equivalent is less than 100, curing may be poor, and if it exceeds 1000, storage stability may be deteriorated. When the component (A) is a compound having a halohydrin group, the hydrolyzable chlorine is not particularly limited, but is usually 10% to 30%.

In the coating resin composition of the present invention, the content of the component (A) is not particularly limited, but is preferably 1 to 90% by weight, more preferably 1 to 50% by weight. If the content is less than 1% by weight, the component (A) may be insufficient and the cross-linking reaction may not proceed sufficiently, resulting in poor curing. If the content exceeds 90% by weight, the component (B) may be insufficient. As a result, the cross-linking reaction may not proceed sufficiently, resulting in poor curing.

<(B) Amino resin>
The amino resin (B) (hereinafter, also simply referred to as the component (B)) is blended as a curing agent for the component (A) in the coating resin composition of the present invention. The reason why the storage stability is improved by using the component (B) is that the number average molecular weight of the component (B) is relatively large, and the amino group involved in the reaction with the component (A) is the component (B) at room temperature. Since it is inside the three-dimensional structure of, it is considered that the reaction with the component (A) is unlikely to occur. Further, the reason why the quick-drying property when curing by heating is improved by using the component (B) is that the amino group has high reactivity with the component (A) in the first place, and the three-dimensional structure of the component (B) is improved by heating. It is considered that the reaction with the component (A) proceeds immediately when the amino group changes and appears on the surface.

The component (B) is not particularly limited as long as the number average molecular weight is 250 to 10,000, and examples thereof include a melamine resin containing a benzoguanamine resin, a urea resin, and a glyoxal resin. These may be used alone or in combination of two or more. Among these, a melamine resin is preferable from the viewpoint of the strength and adhesion of the coating film. The melamine resin is a polycondensate of melamine or a derivative thereof and an aldehyde compound. As the monomer constituting the melamine resin, for example, methylol melamine, benzoguanamine or the like can be used as the melamine or its derivative, and formaldehyde or the like can be used as the aldehyde compound. Can be used. Each of these monomers of melamine or a derivative thereof and an aldehyde compound may be used alone or in combination of two or more.

The number average molecular weight of the component (B) is not particularly limited as long as it is 250 to 10,000, but is preferably 500 to 2,000, and more preferably 700 to 1,300. If the number average molecular weight is less than 250, the quick-drying property may be insufficient, and if it exceeds 10,000, the compatibility with the component (A) may be insufficient.

In the coating resin composition of the present invention, the content of the component (B) is not particularly limited, but is preferably 10 to 10,000 parts by weight, preferably 10 to 500 parts by weight, based on 100 parts by weight of the component (A). It is more preferably a part by weight. When the content of the component (B) is less than 10 parts by weight or exceeds 10,000 parts by weight, the quick-drying property may be insufficient.

The coating resin composition of the present invention may optionally contain other components in addition to the components (A) and (B) as long as the object of the present invention is not impaired. Other components are not particularly limited, but are, for example, solvents, curing accelerators, defoamers, leveling agents, organic thickeners, antioxidants, light stabilizers, adhesive improvers, mold release agents, reinforcing materials. , Softeners, colorants, flame retardants, antistatic agents, wet dispersants and the like.

<Solvent>
The solvent is not particularly limited, and either an aqueous solvent or an organic solvent solvent can be preferably used. For example, aromatic hydrocarbon solvents such as toluene, ethylbenzene, trimethylbenzene and xylene, and fats such as pentane, hexane and cyclohexane are used. Group hydrocarbon solvents, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, alcohol solvents such as methanol, ethanol, isopropanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, methyl cellosolve, ethyl cellosolve, Examples thereof include glycol ether solvents such as butyl cellosolve, methyl diglycol, ethyl diglycol, butyl diglycol and propylene glycol monomethyl ether, ester solvents such as ethyl acetate, butyl acetate and propylene glycol monomethyl ether acetate, and water. Examples of commercially available products that can be used as an aromatic hydrocarbon solvent include Solbesso 100, Solbesso 150, and Solbesso 200. These may be used alone or in combination of two or more.

When the coating resin composition of the present invention contains a solvent, the content thereof may be selected depending on the coating method and the desired film thickness of the cured coating film, and is not particularly limited, but is limited to 100 parts by weight of the component (A). On the other hand, it is preferably 10 to 5000 parts by weight, and more preferably 20 to 2000 parts by weight. If the content is less than 10 parts by weight, the viscosity becomes high and uniform coating may not be possible. If the content exceeds 5000 parts by weight, a coating film having a sufficient film thickness may not be obtained, and it is economical. It is not preferable from the viewpoint of reducing VOC and VOC.

<Curing accelerator>
The curing accelerator is not particularly limited, and is, for example, formic acid, acetic acid, lactic acid, glycolic acid, butyric acid, isobutyric acid, propionic acid, caproic acid, octanoic acid, heptanic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid and thioglycol. Polycarboxylic acids such as acids, malic acid, oxalic acid, succinic acid, malonic acid, fumaric acid, maleic acid, tartaric acid and polycarboxylic acids such as citric acid, benzoic acid, p-toluic acid, p-aminobenzoic acid, P-chlorobenzoic acid, benzoic acid derivatives such as 2,4-dichlorobenzoic acid, phthalic acid derivatives such as phthalic acid, isophthalic acid and terephthalic acid, aromatic carboxylic acids such as salicylic acid, phenol, m-cresol, p-chloro Phenols such as phenol, p-nitrophenol, 2,4-dichlorophenol, o-aminophenol, p-aminophenol and 2,4,5-trichlorophenol, polyphenols such as resorcinol, hydroquinone, catechol and fluoroglusinol , Phenolic resins such as Novorak, methanol, ethanol, propanol, isopropanol, butanol, isobutyl alcohol, aliphatic alcohols such as tert-butyl alcohol, glycols such as ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, glycerin, Examples thereof include glycerols such as polyglycerin, sulfonic acids such as toluene sulfonic acid and methane sulfonic acid, and the like. These may be used alone or in combination of two or more.

When the coating resin composition of the present invention contains a curing accelerator, the content thereof is not particularly limited, but is preferably 0.01 to 2000 parts by weight with respect to 100 parts by weight of the component (A). More preferably, it is 0.1 to 2000 parts by weight. If the content is less than 0.01 parts by weight, the effect of adding the curing accelerator may not be sufficiently obtained, and if it exceeds 2000 parts by weight, the appearance of the coating film may be impaired, which is economical. It may not be preferable from the viewpoint.

<< Members >>
The member of the present invention is characterized by having a resin base material and a coating film formed on the resin base material using the coating resin composition of the present invention.

<Resin base material>
The material of the resin base material is not particularly limited, but polyester such as polyethylene terephthalate and polyethylene naphthalate, polyolefin such as polyethylene, polypropylene and polymethylpentene, polyamide such as nylon 6 and nylon 66, polycarbonate, polyvinyl acetate and polyimide. , ABS resin and the like. Among these, polyester is preferable from the viewpoint of economy and ease of processing.

The thickness of the resin base material is not particularly limited, and a film, a sheet, a plate, a laminate, or the like, which is molded into various molded products manufactured by molding or the like, can be used as the resin base material.

<Coating film>
The coating film is formed on a resin base material using the coating resin composition of the present invention. The method for forming a coating film on the resin base material using the coating resin composition of the present invention is not particularly limited, but the coating resin composition of the present invention is applied to at least one surface of the resin base material. After that, a method of heating and curing can be mentioned. The method of applying the coating resin composition of the present invention and the method of heating and curing the resin composition will be described later.

The thickness of the coating film is not particularly limited, but is preferably 0.1 to 30 μm, and more preferably 0.3 to 20 μm. If the thickness is less than 0.1 μm, the smoothness of the coating film may be insufficient, and if it exceeds 30 μm, the adhesion may be insufficient due to an increase in internal stress.

<< Manufacturing method of parts >>
The method for manufacturing the member of the present invention is a method for manufacturing the member of the present invention.
The step (1) of applying the coating resin composition of the present invention to at least one surface of the resin base material, and
Step (2) of heating the coating resin composition applied in the step (1) at 60 to 250 ° C. for 5 to 300 seconds to cure it.
It is characterized by including.

<Process (1)>
In this step, the coating resin composition of the present invention is applied to at least one surface of the resin base material. The method for applying the coating resin composition of the present invention is not particularly limited, and for example, a bar coating method, a spin coating method, a spray coating method, a dip coating method, a nozzle coating method, a gravure coating method, and a reverse roll coating method. , Die coat method, air doctor coat method, blade coat method, rod coat method, curtain coat method, knife coat method, transferor coat method, squeeze coat method, impregnation coat method, kiss coat method, calendar coat method, extrusion coat method, etc. Can be mentioned.

<Process (2)>
In this step, the coating resin composition applied in step (1) is heated and cured.

In the step (2), the heating temperature is not particularly limited, but is preferably 60 to 250 ° C, more preferably 60 to 150 ° C. If the heating temperature is less than 60 ° C., curing may be poor, and if it exceeds 250 ° C., the shape of the base material may be impaired depending on the material of the resin base material. The heating time is not particularly limited as long as it is 5 to 300 seconds, but is preferably 20 to 120 seconds. If the heating time is less than 5 seconds, curing may be poor, and if it exceeds 300 seconds, the shape of the base material may be impaired depending on the material of the resin base material, and the time required for the process is long. Therefore, it is not preferable from the viewpoint of productivity.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the following examples. Hereinafter, "parts" or "%" means "parts by weight" or "% by weight", respectively, unless otherwise specified.

(Synthesis Example 1)
50 g of sorbitol was dispersed in 20 g of toluene, 0.18 g of tin tetrachloride was added, and 62 g of epichlorohydrin was added over 2 hours in a temperature range of 95 ° C. or higher and 100 ° C. or lower with stirring for reaction. The disappearance of epichlorohydrin was confirmed by the titration method described in JIS K 7236, and toluene used as a solvent was removed by concentration under reduced pressure. The obtained concentrate was dissolved in 100 g of water to obtain an aqueous solution of a sorbitol polychlorohydrin compound (total solid content concentration: 52.5%).

(Material used)
In the following examples and comparative examples, the following materials were used.
(A) Polyfunctional reactive compound sorbitol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, Denacol EX-614B, epoxy equivalent: 173, number of epoxy groups per molecule: 3 to 4)
Bisphenol A diglycidyl ether (manufactured by Mitsubishi Chemical Corporation, 828, epoxy equivalent: 188, number of epoxy groups per molecule: 2)
Sorbitol polychlorohydrin (Synthesis Example 1, number of halohydrin groups per molecule: 2-4)
(B) Amino resin Melamine resin (manufactured by DIC Corporation, Super Beccamin L-145-60, number average molecular weight: 1073, solid content concentration: 55%)
-Amine compound triethylenetetramine (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight: 146)
・ Curing accelerator toluene sulfonic acid ・ Solvent toluene (manufactured by Wako Pure Chemical Industries, Ltd.)
-Resin-based polyester (PET) film (manufactured by Toray Industries, Inc., Lumirror, film thickness 50 μm)

(Examples 1 to 3 and Comparative Examples 1 to 4)
Each component was mixed by the weight ratio shown in Table 1 below to obtain a coating resin composition. The storage stability was evaluated using the obtained coating resin composition by the method described later. Further, the obtained coating resin composition was applied onto a resin base material using a bar coater (No. 2), and cured by heating at 130 ° C. for 60 seconds using a hot air dryer to form a coating film. Was formed to obtain a member. Using a member cooled to room temperature as a test piece, quick-drying property, adhesion and chemical resistance were evaluated by the method described later. These results are shown in Table 1.

(Evaluation method)
-The resin composition for storage stability coating was allowed to stand under the condition of 23 ° C., and the time until turbidity occurred was confirmed. Confirmation was up to 12 hours.
-Quick-drying The coating film of the test piece immediately after preparation was touched with a finger to confirm the presence or absence of tack, and the evaluation was made in two stages according to the following criteria.
◯: No tack ×: With tack ・ Adhesion The coating film of the test piece immediately after preparation was rubbed with a finger 10 times to confirm the presence or absence of peeling of the coating film, and the evaluation was made in two stages according to the following criteria.
◯: No peeling ×: With peeling ・ Chemical resistance A chemical resistance test was conducted using a test piece immediately after preparation. Specifically, a gauze impregnated with methyl ethyl ketone using a rubbing tester was pressed against the surface of the coating film of the test piece under the condition of a load of 300 g and reciprocated 30 times to perform a rubbing test. Was confirmed and evaluated on a two-point scale according to the following criteria.
○: No peeling ×: With peeling

The coating resin composition of the present invention can be sufficiently dried even under low temperature of 130 ° C., 60 seconds, and short-time drying conditions, and the adhesion and chemical resistance of the coating film are also good. It was. On the other hand, in Comparative Examples 1 to 4, which are the prior arts, they could not be sufficiently dried under low temperature and short-time drying conditions, and as a result, the adhesion and chemical resistance were insufficient.

Claims (7)

A composition for coating on a resin base material.
(A) A polyfunctional reactive compound having 2 to 15 epoxy groups and / or halohydrin groups in one molecule, and
(B) A coating resin composition comprising an amino resin having a number average molecular weight of 250 to 10,000 .
Polyfunctional reactive compounds having an epoxy group are sorbitol polyglycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether, isosorbido diglycidyl ether, isomannide diglycidyl ether. , Isoidit diglycidyl ether, or hydrogenated bisphenol A diglycidyl ether for coating . (B) The coating resin composition according to claim 1, wherein the amino resin is a melamine resin. The coating resin composition according to claim 1 or 2, wherein the content of the component (B) is 10 to 10,000 parts by weight with respect to 100 parts by weight of the component (A). (A) The coating resin composition according to any one of claims 1 to 3, wherein the polyfunctional reactive compound has 2 to 10 epoxy groups and / or halohydrin groups in one molecule. A member having a resin base material and a coating film formed on the resin base material using the coating resin composition according to any one of claims 1 to 4. The member according to claim 5, wherein the material of the resin base material is polyester. A method for manufacturing the member according to claim 5 or 6.
The step (1) of applying the coating resin composition according to any one of claims 1 to 4 to at least one surface of the resin base material, and
Step (2) of heating the coating resin composition applied in the step (1) at 60 to 250 ° C. for 5 to 300 seconds to cure it.
A method for manufacturing a member, which comprises.