JPS5920742A - Polypropylene protector molding of automobile - Google Patents

Abstract

PURPOSE:To make it possible to bond a polypropylene resin molding to a car body firmly by an adhesive, by providing integrally the adhesive surface with a specific synthetic layer having a high affinity. CONSTITUTION:A protector molding 3 is made of the bandlike molding main body 5 of a polypropylene resin that has been molded by injection or has been extruded, and a synthetic resin layer 6 of a binary copolymer composed of denatured polyethylene containing glycidyl methacrylate. Since the synthetic resin layer 6 is high in affinity for the adhesive 4, the protector molding 3 can be bended firmly to the surface of the car body 2, and the bonding strength of the protector molding 3 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protecta mold that is adhered to the outer surface of an automobile body with an adhesive, and particularly to a protecta mold made of polypropylene resin.

Generally, in automobiles, shock-absorbing protector molding is adhered to the outer surface of the vehicle body using an adhesive in order to protect the outer panel of the vehicle body from light impacts and to improve the decorative design of the exterior. Conventionally, as such a protector mold, for example, JP-A-53-1213
As disclosed in Japanese Patent No. 21, etc., those made of polyvinyl chloride resin are widely used.

However, products made of polyvinyl chloride resin are heavy because the specific gravity of the polyvinyl chloride resin itself is high (approximately 1.3), which is especially noticeable when the formation is large. Ta. In addition, since the price of polyvinyl chloride resin is relatively high, there is also a tendency to increase the cost.

Therefore, in view of these points, the present inventors have developed a method for protecting protectamol by using a low-specific gravity (approximately 0.92) and low-cost polypropylene resin instead of the conventional polyvinyl chloride resin as the material for protectamol. loss 1
- Attempts were made to downsize and reduce weight.

However, this polypropylene resin has low compatibility with the adhesives (for example, -liquid or two-liquid urethane, RTV silicone, etc.) that are commonly used to bond Protectamol to the outside surface of the car body, and as a result, the adhesive strength is insufficient if used as is. It was found that this made it difficult to securely fix and hold Brotectamol on the outside of the vehicle body, and that it could not be put to practical use.

The present invention was made as a result of extensive experimental research in an attempt to solve this problem.The present invention integrates a special synthetic resin layer that has high affinity with both polypropylene resin and adhesive on the adhesive side of the polypropylene resin molding body. By providing this, the purpose is to enable the polypropylene resin molding body to be firmly adhered to the car body with an adhesive, thereby making it possible to put polypropylene resin protector molding into practical use.

To achieve this objective, the protecta mold of the present invention is composed of a mold body made of polypropylene resin and a synthetic resin layer made of modified polyethylene containing glycidyl methacrylate, which is integrally fixed to the adhesive side of the mold body. The synthetic resin layer is bonded to the outer surface of the car body using an adhesive.

The present invention will now be described in detail based on embodiments shown in the drawings.

In Figures 1 and 2, 1 is in automatic mode,
A series of protector molds 3 made of polypropylene according to the present invention are partially or adhered to the outer surfaces of the side panels and door panels of the vehicle body 2 of the automobile 1 with an adhesive 4 such as two-component urethane or RTV silicone (=I). I'm being kicked.

The protector molding 3 has a strip-shaped molding main body 5 made of polypropylene resin molded by extrusion or injection, and an adhesive surface of the molding main body 5 to the vehicle body 2, as shown in enlarged detail in FIG. A synthetic resin layer 6 of a binary copolymer made of modified polyethylene containing glycidyl methacrylate-1 is fixed to the side of the molding body 5 by coextrusion or thermocompression. Furthermore, the second
In the figure, 7 is a hot melt adhesive for temporarily adhering the protector molding 3 to the vehicle body 2 until the adhesive hardens and reaches practical strength.

Here, to explain the component ratio and layer thickness of the synthetic resin layer 6, if the content of the glycidyl methacrylate component is less than 5% by weight, the affinity of the resin layer 6 for the adhesive 4 will be insufficient, resulting in insufficient adhesion. Since strength cannot be obtained, the content is preferably 5% by weight or more.

Moreover, if the layer thickness of the synthetic resin layer 6 exceeds 2 mm, the resin@
Since the line No. 6 is significantly exposed to the outside and the appearance becomes unsightly, it is preferable to keep it below 2Tr+m.

In addition, when fixing the synthetic resin layer 6 to the molding body 5, a thermocompression bonding method can be used when the layer thickness of the resin layer 6 is relatively thin (approximately 20 μm to 1 mm);
(approximately 600 μm or more), a coextrusion method can be used, and the method may be selected as appropriate depending on the layer thickness.

Therefore, in the above embodiment, the synthetic resin layer 6 made of modified polyethylene containing glycidyl methacrylate 1 which is integrally fixed to the adhesive surface side of the mold body 5 of the protector mold 3 is replaced by the adhesive 4 (-liquid urethane). etc.), the protector mold 3 can be firmly adhered to the surface of the vehicle body 2, and the adhesive strength of the protector mold 3 can be maintained to be improved.

Furthermore, the specific gravity of the polypropylene resin that makes up the molding body 5 of the protector molding 3 is smaller than that of conventional polyvinyl chloride resin (polypropylene resin: 0.92.
Polyvinyl chloride resin: 1°3) and is inexpensive, so it is possible to reduce the weight and cost of the protectamol 3.

In the above embodiment, the protector molding 3 was temporarily attached to the vehicle body 2 using hot melt adhesive 7.7, but as shown in FIG. The protector molding 3' is formed by forming protrusions 6'a and 5'a that protrude from other parts, and by heating and melting the protrusions 6'a and 5'a and welding them to the surface of the vehicle body 2. It may be temporarily attached to the vehicle body 2 by adhesive.

Further, in the above embodiment, the synthetic resin layer 6 was made of a binary copolymer containing only glycidyl methacrylate in modified poly-1-ethylene, but in addition to glycidyl methacrylate, a small proportion of vinyl acetate (for example, 10 weight%
(below) may be added to form a terpolymer. In that case, the melting point of the synthetic resin layer 6 decreases, causing it to stick to the molding body 5 and forming protrusions 51a and 5L as shown in FIG.
Temporary attachment to the vehicle body 2 using method a has the advantage that adhesion can be performed even more easily.

Next, to explain a specific example, the length is 100mTrl.
There are three types of samples (Protector Mol): one in which a synthetic resin layer with a different composition is fixed to the adhesive side of the mold body made of polypropylene resin, and one in which the synthetic resin layer is not fixed and consists only of polypropylene resin. A total of 46 types were prepared, including one type and two types (conventional examples) made only of polyvinyl chloride resin, and some of these six types were primed with urethane coating 1. After (undercoating), it was adhered to the surface of a vertical fixed panel using an adhesive made of liquid urethane. Next, the ambient air humidity of these adhered samples was maintained at approximately 80°C, which corresponds to the temperature of the outer skin of a car body in the hot summer sun, and in this state, a load of 51 was applied to the upper end of the sample at a vertical downward angle. The adhesion of the molding was tested by measuring the distance until it slipped off or peeled off from the panel surface. The test results are shown in Table 1 below.
indicate vinyl acetate, respectively.

In addition, in the "Adhesion" column, "Excellent" means that the number of cases of slipping off during trial 1 is 24.
Things that didn't happen for more than an hour, good is 8 [l? ``Positive'' indicates that the condition occurred in 1 hour or more and less than 8 hours; ``Poor'' indicates that the condition occurred in 1 hour or more and less than 8 hours; ``Poor'' indicates that the defect occurred in less than 1 hour.

As is clear from Table 1, the molding of the present invention, in which a synthetic resin layer is fixed to a molding body made of Polyp P5] and a resin resin, has a greater adhesion force to the panel surface than a molding body made of polypropylene resin only. It can be seen that it adheres and has an adhesive force of approximately 10 J compared to that made of only polyvinyl chloride resin.

In addition, in parallel with the above test, six types of judicial samples were prepared by varying the proportions of each component in the synthetic resin layer, and each sample was primed with urethane paint. Adhesion was tested by contacting the vertical panel surface with an adhesive made of urethane and then applying the same load as above.

At that time, the melting point of each synthetic resin layer was set to 0 (0).

The results of these tests are shown in Table 2 below.

As is clear from Table 2, in order to obtain good adhesive strength, it is necessary to make the content of the glycidyl methacrylate component in the synthetic resin layer 5% by weight or more, and furthermore, When vinyl acetate is added to make the synthetic resin layer a terpolymer, the adhesive strength is further increased due to the synergistic effect of the affinity of glycidyl methacrylate and vinyl acetate for adhesives, and the melting point is also lowered. When temporarily attaching directly to the vehicle body (
It can be seen that this is advantageous in situations such as the state shown in FIG.

As explained above, according to the polypropylene protector mold for automobiles of the present invention, the mold body is made of a polypropylene resin, and the mold body is integrally fixed to the adhesive side of the mold body and is made of a modified polyethylene containing glycidyl methacrylate. The synthetic resin layer has a high affinity with the molding body made of polypropylene resin.The synthetic resin layer increases the affinity with adhesives, allowing the polypropylene protector molding to firmly adhere to the vehicle body. Adhesive strength can be ensured. This makes it possible to put the polypropylene protecta mold into practical use, and has excellent practical effects in that it is possible to reduce the weight and cost of the protecta mold.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and Fig. 1 is a side view of a car equipped with the present invention's tektamol. Fig. 2 is an enlarged sectional view taken along the line ■-■ of Fig. 1, and Fig. 3 is a modified version. FIG. 2 is a diagram corresponding to FIG. 2 showing an example. DESCRIPTION OF SYMBOLS 1... Automobile, 2... Car body, 3.3'... Protector molding, 4... Adhesive, 5... Molding body, 6
．． 6'...Synthetic resin layer.

Claims (1)

[Claims] (1) A protecta mold that is adhered to the outside surface of an automobile with an adhesive, and is composed of a mold body made of polypropylene resin and a modified polyethylene containing glycidyl methacrylate that is integrally fixed to the adhesive side of the mold body. An automatic polypropylene protecta mold consisting of a resin layer.