JPH0346030B2 - - Google Patents

Description

[Detailed description of the invention]

OBJECT OF THE INVENTION (Field of Industrial Application) The present invention relates to a coating composition that is applied to the surfaces of various products such as vehicle interior parts and residential interior decoration parts. (Prior art) The surfaces of resin molded products such as vehicle interior parts, such as instrument panels, armrests, and pillar garnishes, are treated with flocking using pile or suede-like finish for the purpose of protecting and decorating the molded base material. Various decorative treatments have been applied, such as fabric-like synthetic leather, and paint containing fillers such as beads. Furthermore, various decorative treatments are applied to the surfaces of various interior decoration products for homes made of resin molded products for the same purpose as described above. (Problems to be Solved by the Invention) However, the above various decoration processes have the following problems. That is, although the flocked hair has a soft feel, it lacks a moist feel, and moreover, dust tends to adhere to it due to static electricity. In addition, in the case of applying suede-like or fabric-like synthetic leather, these synthetic leathers must be manufactured in a separate process, and since it is necessary to apply it to match the surface shape of the resin molded product, the winding of the terminal part must be The manufacturing process is complicated, and the cost of the product is high, as many processes such as molding are required, and if the surface shape of the resin molded product is complex, it takes a lot of time to paste. become. Furthermore, in the case of a process (rabby painting) in which a paint containing resin beads is applied to the surface of a resin molded product to give it a visually soft feel, the paint film itself is hard and feels soft to the touch. It has the disadvantage that it is not soft and can only provide a product that lacks a luxurious feel. In view of the above-mentioned problems, the present inventors have conducted extensive research on various decorative materials and paints for resin molded products, and have developed a means for imparting a firm, soft texture such as suede-like or backskin-like to the surfaces of these products. This is what led to the discovery of the present invention. Structure of the Invention (Means for Solving the Problems) That is, the present invention comprises a main ingredient consisting of a block type polyisocyanate prepolymer, (b) N ₂ ,
A coating composition is devised whose main components are a microcapsule-type blowing agent containing a gas such as CO ₂ or an alkane, (c) a chain extender, and (d) a filler consisting of cross-linked polystyrene beads. This is an attempt to solve the above problem. (Function) The coating composition of the present invention is applied to the surface of a resin molded product or a product that has been subjected to the above-mentioned known decoration treatment, and the block-type polyisocyanate prepolymer is heated after pre-drying. As the blocks come off and urethane bonds occur, fine bubbles are generated by the foaming agent and a coating film with a soft texture is formed. In addition, together with the action of the filler made of cross-linked polystyrene beads in the above coating composition, a firm and slimy feeling is imparted both in appearance and touch, and in particular, the above-mentioned effect is imparted to the flocked resin molded product. When a coating film is formed, a soft and luxurious decorated skin with a suede-like or backskin-like appearance is obtained. (Example) Hereinafter, the coating composition will be explained in detail using Examples. (a) First, what is a blocked polyisocyanate prepolymer? The terminal -NCO group is blocked with a blocking agent such as alcohols, phenols, ethyl acetoacetate, ε-caprolactam, diethyl malonate, acetylacetone, hydrocyanic acid, or acidic sodium sulfite. It is a polyisocyanate prepolymer that is inactive at room temperature. Examples of the polyisocyanate prepolymers include hexamethylene diisocyanate (HMDI), tolylene diisocyanate (TDI),
4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI)
Among them, non-yellowing HMDI prepolymers (molecular weight = 700 to 5000) are the most suitable isocyanate for forming a soft coating film. Furthermore, it is preferable to use the above block type polyisocyanate prepolymer by dispersing it in water using a nonionic, anionic or cationic surfactant. In this case, the block type polyisocyanate prepolymer and water The appropriate weight ratio is about 1:1. Further, polyester polyols such as polyethylene adipate (PEA), polybutylene adipate (PBA), polyhexamethylene adipate (PHA), polycaprolactone (PCL), and polyoxygen Polyether polyols such as propylene diol (PPG), paritetramethylene glycol ether (PTMG), and polyoxyethylene diol (PEG) can be used, but polyester polyols are suitable for forming soft coatings. However, in the case of polyether-based polyols, it is difficult to obtain coating film strength. (b) Foaming agents include chemical foaming agents that generate N ₂ , CO ₂ or alkanes by thermally decomposing rubber or synthetic resin at a predetermined temperature, and capsule foaming agents that encapsulate organic solvents in synthetic resin microcapsules. However, it is preferable to use a capsule blowing agent whose temperature can be easily controlled, and the amount thereof is 1 to 50 parts by weight per 100 parts by weight of the dispersion of the block type polyisocyanate prepolymer. If the amount of the blowing agent is less than 1 part by weight, the coating film will have a poor soft texture, and if it exceeds 50 parts by weight, the texture of the coating film will become rough. (c) As a chain extender, a cationic surfactant with a molecular weight of 400 or more obtained by reacting a higher fatty acid such as stearic acid or behenic acid with an amino group-containing compound such as aminoethylethanolamine, diethyltriamine, or polyethylene polyamine. is appropriate. In addition, the amount to be blended is 5 to 40 parts by weight per 100 parts by weight of the dispersion of the block type polyisocyanate prepolymer, and if it is less than 5 parts by weight, the soft feel of the coating film will be poor, and if it is less than 40 parts by weight. If it exceeds the limit, adhesive strength, abrasion resistance, and weather resistance will decrease. (d) Next, in order to reduce the tackiness of the paint film, obtain a firm and soft texture, reduce internal friction, and improve weather resistance, microspheres such as polystyrene, crosslinked polystyrene, and acrylic resin are used. It is effective to add a lubricant. The particle size of the lubricant is preferably from several microns to several hundred microns, and the amount added is 100 microns per dispersion of the block type polyisocyanate prepolymer.
The amount is 5 to 20 parts by weight, and if it is less than 5 parts by weight, there is no effect, and if it exceeds 20 parts by weight, the soft texture of the coating film will be poor and the coating composition will be expensive. Furthermore, the coating composition of the present invention containing the above (a) to (d) as main components contains an organic or inorganic pigment or dye. Furthermore, various additives that are usually added, such as anti-sag agents, anti-settling agents,
Leveling agents may also be added. Next, a method of using the coating composition constructed as above will be explained. First, the surface of a resin molded article or the like to be coated is prepared in advance, and then the coating composition is uniformly applied. Note that the coating method may be selected as appropriate, such as spray coating, dipping, brush coating, etc., but spray coating is preferable, and the film thickness varies depending on the type of resin molded product, but is usually several tens of microns to several hundred microns. μ. Next, after the coating film is pre-dried to the extent that it is dry to the touch, the surface thereof is heated to a predetermined temperature. The temperature at this time is the temperature necessary for the blocking agent of the block type polyisocyanate prepolymer to dissociate, and is usually 100°C or higher. When the blocking agent dissociates, the polyisocyanate prepolymer and chain extender react to form urethane bonds. Further, at this time, the foaming agent foams to form fine bubbles in the coating film, so it is necessary to select a foaming agent that foams at around the dissociation temperature of the blocking agent. Next, after the coating film is completely cured, its surface is subjected to post-processing by means such as brushing, buffing, shotplast, etc. Since the texture of the coating film surface changes slightly due to differences in the post-processing means, decorated molded products suitable for various uses can be obtained even when the same coating material is used. Example 1 A coating composition was prepared by blending the raw materials shown in Table-1. On the other hand, a vehicle instrument panel (hereinafter abbreviated as instrument panel) base material was manufactured by injection molding polypropylene resin. Next, a soft intermediate layer made of vinyl chloride resin is coated on the surface side of the same instrument panel base material, and a urethane adhesive is applied to the surface of the soft intermediate layer, and then polyamide staple fibers with a length of 0.4 mm and a fineness of 1 denier are coated. An instrument panel was manufactured by flocking colored pile.

【table】

[Table] Next, the above coating composition was spray applied to the surface of the instrument panel which had been subjected to the flocking process and preliminarily dried at room temperature to form a coating film on the pile. Thereafter, the surface of the coating film was heated for 40 seconds at a temperature of approximately 120° C. to 130° C. using a hot air dryer, thereby foaming the foaming agent and curing the coating film. Next, the surface of the cured coating film was brushed using a nylon brush to separate one to several flocked piles at a time. The instrument panels obtained in the above manner are
As shown in the figure. That is, the surface of a base material 1 made of polypropylene resin is coated with a soft intermediate layer 2 made of vinyl chloride resin and a urethane adhesive 3, and colored piles 4 made of short polyamide fibers are also flocked. In addition, each pile 4 or several piles have a coating film 5 having a large number of fine bubbles 6 inside.
is formed by coating. Due to the synergistic effect of the soft feel of the pile 4 itself and the soft coating film 4, the surface of the instrument panel has a suede-like appearance and feel with a firm and slimy feel, giving it an unprecedented sense of luxury. I was able to get a new instrument panel. Furthermore, since the surface of the instrument panel is coated with a coating film 5 of urethane resin, it also has the property of being less likely to generate static electricity. The coating composition of the present invention is not limited to the above examples, and by varying the blending ratio of each raw material in Table 1 above, the coating composition of the present invention can be applied to the surface of a resin molded article coated with the coating composition. The texture can be subtly changed. Furthermore, the above coating composition can be used not only for the above instrument panel but also for pillar garnish,
It can be applied to various products such as resin molded products, metal, and wood, such as vehicle interior parts such as armrests and home interior decoration products, and in all cases, it has an unprecedented smooth and slimy feel. It is possible to obtain decorative products that are full of luxury. Effects of the Invention As detailed above, the above coating composition can be applied to various products and then heated to foam the foaming agent, thereby creating a decorated skin with a firm, slimy feel and a luxurious feel. The effect is that it is possible to obtain a product that has In addition, it is possible to obtain a soft and luxurious decorative skin through the simple process of painting, without the need for pasting a decorative skin manufactured in a separate process according to the surface shape of the product as in the past. This is an excellent invention that also has the effect of reducing the manufacturing cost of the product.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged sectional view of the instrument panel of the example, and FIG. 2 is an enlarged sectional view of a coating film formed on the pile. 4... Pile, 5... Paint film, 6... Bubbles.

Claims (1)

[Scope of Claims] 1. (a) a main agent consisting of a block-type polyisocyanate prepolymer, (b) a microcapsule-type blowing agent in which a gas such as N ₂ , CO ₂ , or an alkane is sealed, and (c) a chain. A coating composition containing as main components an extender and (d) a filler consisting of cross-linked polystyrene beads. 2. The coating composition according to claim 1, wherein the main ingredient is of a dispersion type using water as a solvent. 3. The coating composition according to claim 1, wherein the blocking agent for the blocked polyisocyanate is ethyl acetoacetate. 4. The coating composition according to claim 1, wherein the chain extender is a cationic surfactant obtained by reacting an amino group-containing compound with a higher fatty acid.