JPS6336626B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyamide resin laminate structure having a strongly adherent aminoalkyd resin coating layer on its surface. Polyamide resin is widely used as a material for various industrial parts, but until now it has been used for internal mechanical parts such as gears, cams, and bearings, so painting has rarely been necessary. However, recently, attention has been focused on its excellent heat resistance and mechanical properties, and polyamide resin has been used for automotive exterior parts such as air spoilers, louvers, cowl top grilles, air outlet grilles, wheel caps, bumpers, etc. are being used. By the way, as a paint for automobile exterior parts,
Amino alkyd resin paint is usually used because of its excellent gloss, texture, hardness, weather resistance, and solvent resistance, but this paint has poor adhesion to polyamide resin, so it cannot be applied directly. I can't. Therefore, until now, when applying aminoalkyd resin paint to polyamide resin, the method used was to soak the surface in a treatment liquid such as a phosphoric acid solution to improve the adhesion to the aminoalkyd resin paint. . However, such a method of immersing in a treatment liquid requires post-treatment such as washing with water and drying, which increases the number of steps and has the drawback of causing dimensional changes due to water absorption. The present inventor has conducted intensive research to overcome the drawbacks of the conventional technology and to develop a polyamide resin that can firmly adhere to the amino alkyd resin coating layer without any pretreatment. It was unexpectedly discovered that when a predetermined amount of a triazine derivative is contained in a polyamide resin, the adhesion between the polyamide resin and the amino alkyd resin paint is significantly improved, and based on this finding, the present invention was accomplished. That is, the present invention provides triazine derivatives of 1.5 to 10
90-98.5% by weight of polyamide resin or a mixture of polyamide resin and rubber and/or thermoplastic resin
The object of the present invention is to provide a laminated structure characterized in that an aminoalkyd resin coating layer is provided on a substrate made of a composition consisting of the following. Examples of the polyamide resin used as a substrate in the present invention include polymers such as ε-caprolactam, aminocaproic acid, ω-laurinlactam, 11-aminoundecanoic acid, hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, and dodecamethylenediamine. Diamines such as methylene diamine, adipic acid, azelaic acid, sebacic acid,
Examples include polycondensates with dicarboxylic acids such as dodecane-diacid and those based on copolymers of these monomers. This polyamide resin may contain rubbers, thermoplastic resins, and the like. Examples of these rubbers include ethylene propylene rubber, acrylonitrile butadiene rubber, styrene-butadiene block copolymer rubber and hydrogenated products thereof, styrene-isoprene block copolymer rubber and hydrogenated products thereof, and carboxylic acid modified products thereof. and mixtures thereof. Examples of thermoplastic resins include polyethylene, ethylene-vinyl acetate copolymer, polypropylene, carboxylic acid modified products thereof (including ionomer resin), acrylonitrile-butadiene-styrene copolymer, and mixtures thereof. be able to. These may be used alone or in combination of two or more. In the present invention, a triazine derivative is used as an adhesion improver, which has the general formula

[Formula] or

These are compounds represented by the formula: (wherein R is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms which may be different from each other), melamines, and melamine cyanurate. Specific examples of compounds represented by the general formula () include cyanuric acid, trimethyl cyanurate, triethyl cyanurate, methyl cyanurate, diethyl cyanurate, tri(n-propyl) cyanurate, etc. Specific examples of the compounds shown include isocyanuric acid, trimethyl isocyanurate, triethyl isocyanurate, methyl isocyanurate, diethyl isocyanurate, tri(n-propyl) isocyanurate, and the like. Melamines are melamine, melamine derivative melamine condensates, and compounds having structures similar to melamine. Specific examples include melamine, ammelide, ammeline, formoguanamine, guanylmelamine, cyanomelamine, arylguanamine, melam, These include melem and melon. Melamine cyanurate is an equimolar reaction product of melamine and cyanuric acid or isocyanuric acid. Among these, melamine cyanurate is particularly preferred because it significantly improves adhesion. The triazine derivative is added to the polyamide resin composition in an amount of 1.5 to 10% by weight. If it is less than 1.5% by weight, the effect of improving the adhesion with the amino alkyd resin paint will be insufficient, and if it exceeds 10% by weight, it will adversely affect moldability and mechanical properties, which is not preferable. The method for preparing the triazine derivative-containing polyamide resin is not particularly limited, and any method may be used as long as the triazine derivative is uniformly dispersed in the polyamide resin. Specific methods include dry blending a polyamide resin and a triazine derivative, melt-mixing and extruding this dry blend to form pellets, and preparing master pellets kneaded with a predetermined amount or more of a triazine derivative. Examples include a method of dry blending the polyamide resin with a polyamide resin for dilution, or a method of adding a triazine derivative during polymerization of the polyamide resin. The final molded product may be formed by molding the triazine derivative-containing polyamide resin using a conventional molding machine (injection molding machine, extrusion molding machine, etc.) according to a conventional method. If desired, a cationic or nonionic surfactant may be added to the substrate of the present invention as a mold release agent. The amino alkyd resin coating layer provided on the substrate formed in this manner is formed using a coating material consisting of a mixture of an alkyd resin and an amino resin. The alkyd resin used in this case is, for example,
Condensates of polyhydric carboxylic acids such as maleic anhydride, phthalic anhydride, and isophthalic anhydride or their anhydrides and polyhydric alcohols such as glycerin and pentaerythritol, or the condensation of these with coconut oil, linseed oil, castor oil, or It is an oil-modified alkyd resin modified with fatty acids such as soybean oil and tall oil. On the other hand, amino resins include, for example, butoxymethylol urea and butoxymethylol melamine, which are made oil-soluble by etherifying a condensate of urea or melamine and formaldehyde with an alcohol such as butanol. In the present invention, to form the aminoalkyd resin coating layer on the substrate, commonly used coating methods such as brush coating, dip coating, spray coating, and electrostatic coating are used. The thus obtained laminated structure of the present invention has a polyamide resin base and an aminoalkyd resin coating layer firmly adhered to each other and does not easily peel off, so it can be used as an automobile exterior part or other material. It can be used suitably. Next, the present invention will be explained in more detail with reference to Examples. Note that the characteristic values in the examples were measured by the following method. (1) Adhesion (a) Normal state: In accordance with JIS K5400-1979, a 1 mm square grid test was conducted to determine the area percentage that would not peel off. (b) After thermal shock: Thermal shock test (-30℃ x 1hr~90
℃ × 1 hr), a grid test was performed to determine the area percentage that did not peel off. Examples 1 to 4, Comparative Example 1 An aqueous solution of hexamethylene diammonium adipate salt and an equimolar mixture powder of melamine and cyanuric acid were added to an autoclave equipped with a pressure gauge, a pressure control valve, and a stirrer, and the presence of water was Polymerization was carried out under standard polymerization conditions to obtain nylon 66 containing 5% by weight of melamine cyanurate. This material was injection molded to create a flat plate (length 120 mm, width 80 mm, thickness 3 mm). This flat plate was coated with amino alkyd resin paint (manufactured by Kansai Paint Co., Ltd., Amirac No.
1000, White No.531, diluted with special thinner (15
Second/FC#4) and used) was air sprayed.
After being left at room temperature for 30 minutes, it was heated and cured at 140°C for 30 minutes to obtain a coated product. The coating thickness of the painted object was approximately 40 μm. Table 1 shows the results of measuring the adhesion of this coated product. Table 1 also shows the results of varying the amount of melamine cyanurate. Example 5, Comparative Example 2 95 parts by weight of nylon 6 (CM 1017, manufactured by Toray Industries, Inc.) were added and mixed with 5 parts by weight of melamine cyanurate powder, and pellets were prepared using an extruder. Using this pellet, a coated article was prepared in the same manner as in Example 1, and the adhesion was measured. The results are shown in Table 1. For comparison, Table 1 also shows the results without the addition of melamine cyanurate. Examples 6-7 Instead of melamine cyanurate in Example 5,
A coated article was prepared in the same manner as in Example 5 except that melamine powder and cyanuric acid powder were used, and the adhesion was measured. The results are shown in Table 1.

【table】

[Table] Example 7, Comparative Example 3 Using nylon 66 containing 5% by weight of melamine cyanurate from Example 1 as a base polymer, ethylene propylene rubber (EP51 manufactured by Japan EP Rubber Co., Ltd.) and ionoma resin (Surlyn A1706 manufactured by DuPont)
Add and mix, using an extruder, melamine cyanurate content 5% by weight, ethylene propylene rubber content 10% by weight, ionomer resin content 20% by weight
pellets were prepared. Using this pellet, a coated article was prepared in the same manner as in Example 1, and the adhesion was measured. The results are shown in Table 2. Further, for comparison, the results of the sample not containing melamine cyanurate are also shown in Table 2.

[Table] Polyamide resin molded articles containing a specific amount of triazine derivatives, particularly melamine cyanurate, had excellent adhesion to aminoalkyd resins and were sufficiently usable for practical use.

Claims (1)

[Claims] 1. An aminoalkyd resin coating layer is provided on a substrate composed of a composition consisting of 1.5 to 10% by weight of a triazine derivative and 90 to 98.5% by weight of a polyamide resin or a mixture of polyamide resin and rubber and/or thermoplastic resin. A laminated structure characterized by: