JPH021667B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) This invention relates to a coated fiber-reinforced urethane molded article, specifically, the adhesion between a urethane molded layer reinforced by mixing single fibers and a coating film provided on the surface of the molded layer. This invention relates to fiber-reinforced urethane products with improved properties. (Prior art) In order to reduce weight and reduce vibration and noise in automobiles, fiber-reinforced urethane molded products are used in areas where relatively low strength is required, such as the interior materials of the car body and the fenders on the outer panel of the car body. used. Conventionally, as shown in FIG. 5, this type of fiber-reinforced urethane molded product is made by coating and baking a urethane paint on the surface of a urethane molding layer 11 reinforced by mixing single fibers 10 to form a primer 12. It is known that after cooling, the surface of the primer 12 is coated with a different type of urethane paint to form a top coat 13. However, in this type of conventional urethane molded product, the primer 12 which is the base of the top coat 13 is
is soft, so when the urethane molded layer 11 is left to cool, the molded layer 11 heat-shrinks and the reinforcing fibers 1
0 protrudes from the surface of the molding layer 11, causing unevenness on the surface, which causes the surface of the primer 12 to also become uneven, causing the problem that the surface of the top coat 13 becomes rough. In addition, when comparing the finish quality of this type of conventional urethane molded product and painted steel parts, the finish quality of the steel parts was compared.
Expressed in PGD value, it is usually 0.7 to 0.8, which is good, but the PGD value of the conventional urethane molded product mentioned above is
0.3 to 0.5, and if they were placed adjacent to each other, there was a problem that the appearance would not be harmonious. In contrast, the present applicant has formed a hard urethane-based primer containing 5 to 15% by weight of flaky aluminum, which is dispersed and precipitated on the urethane molding layer side, on the surface of the urethane molding layer mixed with reinforcing fibers. ,
The flaky aluminum suppresses the protrusion of reinforcing fibers, and the primer has a specified hardness to prevent unevenness on the coating surface caused by heat shrinkage of the molding layer. has already been proposed (Japanese Unexamined Patent Publication No. 60-24947). This method of containing 5 to 15% by weight of flaky aluminum to prevent roughness in the top coat shows excellent effects when the reinforcing fiber content of the urethane molding layer is up to 10% by weight. If the reinforcing fiber content increases further than this, there is a possibility that it will not be able to cope with the problem sufficiently. In this case, it is conceivable to further increase the content of flaky aluminum, but if the flaky aluminum is simply increased, the flaky aluminum will overlap, making it difficult for the paint to spread, and the primer will The surface of the primer becomes microscopically uneven, causing rough skin.Furthermore, the solvent of the top coat is sucked into the microscopic unevenness of the primer, displacing the primer, and the solvent balance of the topcoat is disrupted, causing the topcoat to become blurry and cloudy. Problems arise. Therefore, the applicant has added non-leaf flaky aluminum to the surface of a urethane molding layer mixed with reinforcing fibers, which is dispersed and precipitated on the urethane molding layer side.
A hard urethane base coat containing 10 to 40% by weight is formed, a hard urethane intermediate coat is formed on top of this, and a top coat is formed on top of this to remove phosphorus from the base coat. A method has already been proposed in which the protrusion of the reinforcing fibers is suppressed by aluminum flakes, and the roughness on the surface of the coating film caused by the increase in flaky aluminum is eliminated by the above-mentioned intermediate coating film. (Japanese Patent Application Laid-open No. 60-94349). According to these proposals (JP-A-60-24947 and JP-A-60-94349, even when the reinforcing fiber content of the urethane molding layer is up to 10% by weight,
Even when the content is 10% by weight or more, the protrusion of the reinforcing fibers is effectively suppressed and the occurrence of unevenness on the surface of the coating film is prevented. It has the property of causing deterioration. Therefore, the adhesion of the hard urethane primer (undercoat film) containing flaky aluminum to the urethane molding layer is poor, resulting in the problem that the paint film peels off from the urethane molding layer. (Object of the Invention) The present invention has been made to solve the above problems, and includes a coating that can improve the adhesion between the urethane molding layer and the coating film provided on the surface of the urethane molding layer. The purpose of this invention is to provide fiber-reinforced urethane molded products. (Structure of the Invention) In order to achieve the above object, the present invention provides a soft urethane-based undercoat film on the surface of a urethane molded layer mixed with reinforcing fibers, and on top of this a hard urethane-based undercoat film containing non-leaf flaky aluminum. A urethane-based intermediate coat film is formed, and a urethane-based top coat film is formed on top of this.The base coat film improves the adhesion between the urethane molding layer and the paint film, and also improves the adhesion of the intermediate coat film. The flaky aluminum suppresses the protrusion of reinforcing fibers and eliminates roughness on the coating surface. (Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows a coated fiber-reinforced urethane molded product according to the present invention, in which 1 is R-
This is an R1M urethane-based molding layer, and the molding layer 1 contains at most 25% by weight of glass fiber (or mineral fiber) 2 having a length of 1/16 to 1/8 inches as reinforcing fibers. The surface of the molded layer 1 is undercoated with a soft urethane paint, that is, a urethane lacquer type forced drying paint to form a primer (undercoat film) 3, and the surface of the primer 3 is coated with a hard urethane paint. An intermediate coating is applied to form a sealer (intermediate coating film) 4,
The sealer 4 contains 5 to 40% by weight of flaky aluminum 5 which has good affinity with the paint and disperses and settles on the urethane molding layer 1 side. Further, a different type of urethane paint is applied and baked on the surface of the sealer 4 to form a top coat (top coat) 6. The above primer 3 and sealer 4 have an elongation rate of 10
% or less, it will not be able to follow the deformation of molding layer 1 due to heat shrinkage and cracks will occur, so the elongation rate of top coat 3 is 300 to 400%, and the elongation rate of sealer 4 is 10 to 140%. This is desirable. Also,
The top coat 3 and sealer 4 may be formed by either a spray method in which the urethane molding layer 1 is applied after molding, or a mold coat method in which the molding mold is spray coated and molded. Specific top coat 3 in spray method,
Table 1 shows the composition and coating specifications of Sealer 4 and Top Coat 6.

【table】

【table】

[Table] In the above table, So stands for solid, Me stands for metallic, setting stands for the standing time to remove the solvent after painting, and 1Pu and 2Pu in the paint column indicate 1-component polyurethane and 2-component polyurethane, respectively. Indicates type polyurethane. Here, the reason why the content of flaky aluminum 5 and the film thicknesses of primer 3 and sealer 4 were set as shown in Table 1 is as follows. (i) Content of flaky aluminum If the content is less than 5% by weight, the effect of suppressing the protrusion of fibers in the molded product will be small, causing surface roughness on Top Coat 6, while if the content is more than 40% by weight, the coating film will deteriorate. This is because the flexibility of the coating decreases and cracks occur in the coating film. (ii) Film thickness of primer 3 In the spray method, the film thickness of primer 3 is
If the thickness is less than 20 μm, the coating film will become uneven, while if the thickness is 25 μm or more, the coating film will sag, making it impossible to obtain a uniform coating film, and the surface will become rough. (iii) Film thickness of sealer 4 In the spray method, the film thickness of sealer 4 is 30 μm.
Below, the effect of Primer 3 cannot be suppressed, the coating film becomes uneven, and the effect of suppressing fiber protrusion is small; on the other hand, the film thickness is
If it is more than 40 μm, the coating film will sag, making it impossible to obtain a uniform coating film, and the solvent will not drain easily and the surface will become rough. In the above structure, even when the amount of reinforcing fibers in the urethane molding layer 1 is large, the urethane molding layer 1 is
The protrusion of the fibers 2 on the surface is suppressed. Moreover, since the soft urethane-based primer 3 is provided, the adhesion of the primer 3 to the urethane molding layer 1 is improved, thereby preventing the coating film composed of the sealer 4 and the top coat 6 from peeling off. Furthermore, since the primer 3, sealer 4, and top coat 6 are coated in layers, the smoothness of the surface of the top coat 6 is guaranteed by this layered coating effect. Next, the present inventor has determined the adhesion and image clarity (finishability) of the molded product of this invention and the molded product of the prior invention.
A comparative test was conducted. The results are shown in Table 2.

[Table] In the above table, the adhesion strength is the value measured using a tensile tester as the force with which a 1 cm wide coating film is peeled off from the molded layer. As is clear from Table 2, the molded product of this invention is
The adhesion strength has been improved, and the finish is 0.7~08.
This value is almost the same as the paint finish level of a normal steel body, and is a good finish, ensuring a harmonious appearance. In addition, the inventor has also discovered that 3
type of aluminum, namely a (average particle size 1μ
The primer, sealer, and top (So) in Table 1 above are used. The relationship between aluminum content and finish quality was investigated. The results are shown in FIG. According to this Figure 2, regardless of the type of aluminum, the aluminum content of Sealer 4 is 5 to 5.
It can be seen that a good finish with a PGD value of 0.7 to 0.8 can be obtained in the range of 15% by weight. Furthermore, the same three types of aluminum as in the case of Figure 2 were contained, and the relationship between aluminum content and finish was investigated using the primer, sealer, sealer, and top (So) in Table 1 above, and the test results were as follows. It is shown in Figure 3. According to FIG. 3, regardless of the type of aluminum, if the aluminum content of the sealer 4 is 10% by weight or more, a good finish with a PGD value of 0.7 to 0.8 can be obtained. Next, the inventor investigated the relationship between the aluminum content in Sealer 4 and the low-temperature flexibility (-30°C) of the coating film. The test in this case was conducted as follows. In other words, 20μ of Primer 3 from Table 1 above was applied to a test piece with a width of 20mm and a length of 250mm.
Form 30μ of sealer, 30μ of sealer, and 30μ of top coat (So), and make this test piece with a diameter of
The film was wrapped around 50 mm, 100 mm, and 200 mm cylinders, and the flexibility was determined based on the presence or absence of cracks on the coating surface. The test results are shown in FIG. According to FIG. 4, it can be seen that when the aluminum content of the sealer 4 becomes 40% by weight or more, the low-temperature flexibility is greatly reduced. Therefore, from the viewpoint of finishability, the aluminum content should be 5% by weight or more, but when low-temperature flexibility is taken into consideration, the appropriate aluminum content is 5 to 40% by weight. (Effects of the Invention) As explained above, according to the present invention, the adhesion of the coating film to the urethane molding layer is improved, and the finish quality is guaranteed.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a coated fiber-reinforced urethane molded product according to an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between aluminum content and finish quality of an embodiment of the present invention, and FIG. Figure 3 is a diagram showing the relationship between aluminum content and finish quality in other embodiments of the present invention, Figure 4 is a diagram showing the relationship between aluminum content and low temperature flexibility, and Figure 5 is a diagram showing the relationship between aluminum content and low temperature flexibility in another embodiment of the present invention. FIG. 2 is a cross-sectional view of a fiber-reinforced urethane molded product. 1... Urethane molding layer, 2... Single fiber, 3...
Undercoat film, 4: Intermediate coat film, 5: Scale-like aluminum, 6: Top coat film.

Claims (1)

[Claims] 1. A soft urethane-based undercoat film is provided on the surface of the urethane molding layer reinforced by mixing single fibers, and a hard urethane-based primer film containing scale-like aluminum that is dispersed and precipitated toward the urethane molding layer is applied on top of this. A coated fiber-reinforced urethane molded product characterized by providing an intermediate coating film and further providing a urethane-based top coating film on the intermediate coating film.