JPS63214419A - Production of window glass for vehicle - Google Patents

Abstract

PURPOSE:To obtain a window glass for vehicle having excellent durability, high performance and pretty appearance in high productivity, efficiently and at a low cost, by carrying out at least one injection molding of multi-colored molding by utilizing an injection compression molding. CONSTITUTION:A molded item of a thin thickness and on which a molding pressure is uniformly applied can be obtained by applying compression on a resin 20 injected from a nozzle 21a in metal molds 21 and 22 before it is cooled and solidified. When the molded item is relatively small, a molding method where the resin is filled into the end corner of the mold while the compression allowance of 5-10% of the thickness of the molded item is kept as an allowance for compression, is preferable. On the other hand, when the molded item is relatively large, as it becomes hard that the resin will flow sufficiently in the mold, it is preferable that a method where a part for compression allowance d is taken largely in advance against the thickness D of the molded item is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a vehicle window glass, and more particularly to a method for manufacturing a vehicle window glass in which the peripheral edge masking portion is improved.

[Prior Art and Prior Art] Generally, the lower part of a windshield of an automobile is made of a steel plate, in which a windshield 1 is interposed on an instrument panel 2 with a molding 3, as shown in FIG. Normally, the back surface 3a of this molding 3 has scratches during molding and dirt from attaching the metal foil, and the back surface 3a of this molding 3 can be seen by the driver or passenger seat through the transparent windshield 1. When it enters the visible range, it looks bad and seriously spoils the aesthetics of the front of the car.

Therefore, conventionally, a masking 5 is applied to the peripheral edge of the windshield through which the line of sight A of a person inside the car passes through and the back surface 3a of the molding 3 is visible.
A is hidden from view.

Conventionally, as such masking, inorganic glass windows are coated with a smoke coloring. However, coloring inorganic glass is technically extremely difficult and costly.

Among window glasses made of organic glass, hard-coated injection molded products or sheet molded products with deep or sharp bends are masked by the following steps (1) to (2).

■ Cover the non-painted area (glass substitute surface) with tape and paper, exposing the surface to be masked, and create a boundary (partition) between the surface to be painted and the surface not to be painted.

■ Use sandpaper or sandblasting to make scratches on the surface to be masked.

■ Painting is done by spraying.

■ Bake the paint in a drying oven.

■ After being taken out of the oven and cooled down, slowly peel off the tape and paper attached to the glass substitute surface, being careful not to make the parting line uneven.

In addition, for shallowly bent or flat sheet-shaped organic window glass, the above processes (1) and (2) are applied after painting by screen printing, similar to general glass masking.

Among the conventional masking painting methods mentioned above, those that go through the steps from ■ to ■ require a large number of masking steps, resulting in very low productivity, as well as problems with how to apply the tape, how to paint, and how to remove the tape after painting. It requires skill, and due to poor adhesion between the hard coat surface and the masking agent, it is extremely difficult to form clean edges without unevenness, and the workability is poor. Moreover, there is also the problem of peeling of the masking paint film due to poor adhesion between the hard coat surface and the masking agent, resulting in poor manufacturing yields.

Although the screen printing method has good productivity to some extent, the masking painting process still poses a major problem in terms of window glass productivity, cost, etc.

In order to solve these problems, the applicant has:
For example, as shown in FIGS. 2(a) to 2(g), a vehicle window glass 10 made of organic glass has a colored portion 12 formed on the peripheral edge of a transparent glass portion 11 by a multicolor molding method. An application was previously filed for utility model registration (Utility Model Application No. 150138/1983, hereinafter referred to as the "earlier application").

The above-mentioned vehicle window glass of the earlier application uses a multicolor molding method to form the colored part (masking part) at the same time as the transparent glass part of the main body, so the painting process can be completely omitted, increasing productivity. In addition, since the masking part is not painted, there are no problems such as peeling of the paint film, and the durability is good.

[Problems to be Solved by the Invention] However, when forming a colored part on the peripheral edge of a transparent glass part using a multicolor molding method, there is a problem that it is difficult to obtain a product with the shape of the mold for the following reasons. be.

That is, for example, in the case of two-color molding, (1) Deformation occurs during mold release due to the difference in shrinkage between the different materials of the primary molding material and the secondary molding material, and the difference in shrinkage time due to the subsequent cooling of the secondary molding part. .

■ Due to large residual internal stress, deformation occurs during post-processing such as hard coat firing.

■ Especially in the case of a design that requires a difference in the thickness of the primary molded part and the thickness of the secondary molded part, the product may warp or distort due to sink marks and shrinkage differences due to the difference in thickness, resulting in poor mold shape retention. . For example, in the case of the vehicle window glass 10 as shown in FIG. 2(d), deformation as shown in FIG. 5(a) or (b) occurs, and the boundary between the transparent glass portion 11 and the colored portion 12 At V, perspective distortion occurs due to sink marks.

Furthermore, since large residual stress remains in the molded product, especially in the gate part during injection molding, cracks may occur near the gate part during the hard coating process, depending on the resin and hard coating agent used. Another drawback is that there are restrictions on the coating conditions.

[Means for Solving the Problems] The method for manufacturing a vehicle window glass of the present invention includes the steps of manufacturing an organic glass vehicle window glass having a colored portion on the peripheral edge of a transparent glass portion by a multicolor molding method. It is characterized in that at least one injection molding of the multicolor molding is performed by injection compression molding.

Hereinafter, the present invention will be described in detail with reference to the drawings.

In the present invention, the multicolor molding method is basically based on the conventional method, but the mold design structure and molding conditions are appropriately set in order to achieve quality as an organic glass window material for vehicles. is preferred.

In addition, in the present invention, when manufacturing vehicle window glass by injection molding using a multicolor molding method, normally the transparent glass part is molded first, and then the colored part is molded, but the shape of the window glass and the masking configuration In some cases, the colored part is molded first.

Therefore, in the method of the present invention, at least one injection molding for multicolor molding is performed by injection compression molding.

In carrying out the present invention, for example, a compression process is added to multi-color molding using an inversion table, which has been commonly performed in the past. For example, the compression process may be used for all injection molding.

For example, in the case of two-color molding, ■ Apply compression only to the primary side.

■ Apply compression only to the secondary side.

■ Apply compression to both primary and secondary.

Either of these can be adopted.

- It is effective to apply compression to at least the transparent part of the window glass (this part is usually considered to be the primary molding side).

The injection compression method is not particularly limited and is determined depending on the size of the molded product.

For example, in the case of a relatively small molded product, 5% of the molded product wall thickness.
A molding method in which the resin is filled to the end of the mold while maintaining a compression allowance of ~10% is suitable. In this case, the method for maintaining the compression allowance may be either an oil block method or a mechanical block method. Alternatively, it is also possible to adopt a so-called two-stage mold clamping method, in which the mold clamping pressure is lowered to a low level, the mold is clamped, and then the mold is injected, and the movable mold is moved back by the injection pressure to obtain the compression margin, without setting the compression margin in advance. .

On the other hand, in the case of relatively large molded products, it becomes difficult for the resin to flow sufficiently within the mold, so as shown in Figure 1 (a), the compression allowance d should be increased in advance to compensate for the wall thickness of the molded product. It is preferable to adopt the method of leaving it open.

In the case of the above-mentioned relatively small molded product where the resin is sufficiently flowable, the resin is filled to the end of the mold upon completion of injection, whereas in the case of a relatively large molded product like this, the resin is filled to the end of the mold. For materials that cannot flow sufficiently in the mold, when injection is completed, the mold 2 usually
The resin 20 has not reached the end of 1.22.However, even in this case, the flow path is widened by the compression margin d, so the fluidity of the resin is improved. However, nozzle 21
The resin 20 injected from a is released to atmospheric pressure. Until the resin itself cools and solidifies, it can flow and reach the end of the mold, so as shown in Figure 1 (b), by applying compression before the resin cools and solidifies, it is possible to form a thin wall. A molded product with uniform pressure can be obtained. Therefore, in the case of large molded products, it is advantageous to adopt such a method.

It should be noted that it is generally easier and more advantageous in terms of equipment and equipment to provide such an injection compression step on the primary injection side than on the reverse side of molding for other colors.

FIGS. 2(a) to 2(g) are schematic cross-sectional views showing examples of vehicle window glasses manufactured by the method of the present invention.

The vehicle window glass 10 manufactured according to the present invention is made of organic glass, and as shown in FIGS. 2(a) to 2(g), the periphery of the transparent glass portion 11 is colored by a multicolor molding method. The portion 12 is formed.

In the present invention, the colored portion 12 to be formed is formed on the window glass 10.
There is no particular restriction on the cross-sectional shape of the colored portion of the peripheral portion of the coloring portion.

For example, as shown in FIGS. 2(a) to 2(c), various shapes such as a square, a triangle, and a U-shape can be used. Further, as shown in FIG. 2(d), it may be provided only on one side of the window glass. In the case of the configuration shown in FIG. 2(d), the colored part 12 is covered with the transparent glass part 11, so that the colored part 12 is given a beautiful and ristal look. Coloring section 12
is not limited to the case where it is provided flush with the transparent glass part 11 as shown in FIGS. 2(a) to (d), but also when it is provided flush with the transparent glass part 11 as shown in FIGS. 2(e) to (g). may be provided so as to protrude from the transparent glass portion 11. The shape etc. of this colored portion 12 can be easily set by changing the mold design structure.

In the present invention, as the transparent glass material, thermoplastic resins such as polycarbonate, acrylic resin, ABS (acrylonitrile/butadiene/styrene) resin, and AS (acrylonitrile/styrene) resin are preferred because they are easy to mold. It may also be a thermosetting resin.

Various colored resins can be used as the material for the colored part, but the resin used for the transparent glass material, colored with an appropriate pigment, has better compatibility with the transparent part (bondability or adhesion during molding). or integrity after molding, etc.) is preferable. Of course, other general purpose resins colored with suitable pigments can also be used. As the resin for the colored part, polyethylene resin, vinyl chloride resin, etc. are generally preferred because they are inexpensive.

The vehicle window glass manufactured by the present invention can be used for windshields of various vehicles such as automobiles such as passenger cars and freight cars, and trains.
Of course, it can also be applied to rear side glass (triangular window), roof glass, etc. In addition, it can also be used for tail lenses, etc. Generally its size is 150cm x 1
Although it is within 50 cm, it may be larger.

In addition, the dimensions of the colored part to be formed vary depending on the shape, size, use, and purpose of forming the colored part of the window glass, and are determined as appropriate. When the windshield 10 has a length t of 2 to 8 mm, the sizes of the colored portions 12 to be formed are the values of a and b in FIG. 4, such that a=0, 5 to 2 mm, and b=5. ~5
It should be approximately 0 mm.

The vehicle window glass manufactured by the present invention may be hard-coated according to a conventional method, but in that case, problems such as peeling due to poor adhesion between the hard-coated surface and the masking agent and cracks in the hard-coated surface may occur. It is possible to apply a hard coat extremely well.

In addition, in FIGS. 2(a) to (g) and FIG. 4, since the window glasses of the present invention are schematically shown, the window glasses are all in the shape of a flat plate, but the present invention has a curved shape. Needless to say, the present invention can also be applied to the manufacture of plate-shaped window glasses.

The multicolor molding method employed in the present invention can be applied not only to masking the periphery of a window glass but also to the formation of marks and decorative windows (garnishes). In this case, the marks and garnishes may be formed together with masking around the edge of the window glass,
Only the marks and garnishes may be formed using a multicolor molding method.

[Operation] In the injection compression method, the molding material is filled with resin while the mold is opened in advance, so at the stage of injection and flow of the resin into the mold, the resin is made to flow more and reaches the end of the mold. can be done. After that, pressure is applied to compress the resin, making it possible to obtain thin-walled molded products that cannot be achieved with normal injection molding.Furthermore, uniform pressure is applied over the entire surface of the molded product, reducing internal residual strain. Fewer molded products can be obtained.

For this reason, ■ Shape retention of molded products is greatly improved.

■ Sink marks and shrinkage in each part of the molded product become uniform, improving the surface accuracy of the molded product.

■ Perspective distortion at the boundary between the transparent glass part and the colored part is reduced.

■ Cracks in the hard coat are prevented.

The following effects are achieved.

[Example] Examples will be described below.

Example 1 Injection compression molding as shown in FIGS. 1(a) and (b) was adopted for the transparent glass part molding side of the primary molding, and according to the method of the present invention, as shown in FIG. 2(d). manufactured window glass.

The molding material, molding conditions, and shape of the molded product are as follows.

Molding material Transparent glass part: Polycarbonate resin layer Color part: Polycarbonate resin (contains 0.5% by weight of black pigment carbon black) Molding conditions Injection compression molding allowance d: 0.2 cm Size of 15 cm Length: 42 cm Width: 23cm Thickness: 0.4cm Colored part (values of a and b shown in Figure 4) a: 0. 2 cm b: 3 cm As a result, the obtained window glass material had good shape retention and did not undergo deformation during mold release or post-processing. Furthermore, the perspective distortion at the boundary between the transparent glass part and the colored part was also good.

Next, the obtained window glass was subjected to hard coat treatment under the following conditions.

Hard coat agent: Silicone thermosetting type (with primer treatment) Processing conditions: 120℃, 60 minutes As a result, the window glass did not deform due to the hard coat treatment, and cracks were generated near the gate. There was no such thing.

[Effects of the Invention] As detailed above, the method of the present invention employs the multicolor molding method to produce an organic glass vehicle window glass having a colored portion on the peripheral edge of the transparent glass portion by the multicolor molding method. At least one injection molding is performed by injection compression molding, and the molding material resin is filled with the mold open.
The resin can be filled to the end of the mold with good fluidity.

For this reason, ■ It becomes possible to mold large molded products.

■High viscosity materials can be used.

■ Thin wall molding is possible.

■ Anisotropy in strength and contraction disappears.

■ Can be molded at low pressure.

■ Can be molded at low temperatures.

Effects such as these are produced.

In addition, uniform pressure is applied to the entire surface of the molded product, resulting in a molded product with less internal residual strain, so (1) the shape retention of the product is improved.

■ Sink marks and shrinkage are reduced, and perspective distortion is improved.

■ Solve the problem of cracks occurring during hard coating treatment.

[Phase] From ■ to ■, the degree of freedom in designing the masking part of the product is increased, and the design quality is improved.

Effects such as these are produced.

Therefore, according to the method of the present invention, a highly durable, high-performance, and beautiful vehicle window glass can be manufactured efficiently and at low cost with high productivity.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are partial sectional views of a mold for explaining the present invention in detail, and Figures 2 (Cts) to (g) show examples of vehicle window glass manufactured by the present invention. A schematic sectional view, FIG. 3 is a sectional view illustrating a windshield attachment part of an automobile, FIG. 4 is a schematic sectional view of a vehicle window glass manufactured by the present invention, and FIG. 5(a). (b) is a sectional view showing a strain-generating part of the window glass. 10... Vehicle window glass, 11... Transparent glass part, 12... Colored part. Agent Patent Attorney Tsuyoshi Shigeno Figure 1 (a) Figure 2 Figure 5

Claims (2)

[Claims] (1) In manufacturing an organic glass vehicle window glass having a colored portion on the peripheral edge of a transparent glass portion by a multicolor molding method, at least one injection molding of the multicolor molding is performed by injection compression molding. A method for manufacturing vehicle window glass. (2) The method according to claim 1, wherein at least the transparent glass portion is formed by injection compression molding.