JPH07100331B2 - Vehicle window glass manufacturing method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 having an improved masking portion at the peripheral edge.

[Prior Art and Prior Art] Generally, the lower part of the windshield of an automobile has a structure in which a windshield 1 is fixed to an instrument panel 2 with a molding 3 as shown in FIG. Usually, the back surface 3a of the molding 3 is left with the scratches during molding and the dirt when the metal foil is attached, and the back surface 3a of the molding 3 is exposed to the driver or passenger in front through the transparent windshield 1. In the visible range, the appearance is bad, and the aesthetics of the front part of the car are significantly impaired.

In view of this, conventionally, masking 5 is applied to the peripheral portion of the windshield where the line of sight A of a person in the vehicle is transmitted and the back surface 3a of the molding 3 is in view so that the back surface 3a cannot be seen.

Conventionally, a smoke-colored coating is applied to an inorganic glass window glass as such masking. However, coloring the inorganic glass is technically extremely difficult and costly.

A hard-coated injection-molded article or a sheet-molded article having a deep bend or a sharp bend in the window glass made of organic glass is masked by the following steps (1) to (3).

Cover the non-painted area (glass alternative surface) with tape and paper, and expose the masking planned surface to create a boundary (partition) between the painted surface and the unpainted surface.

Make a scratch on the surface to be masked using a paper file or sandblast.

 Painting by spraying.

 Bake the paint in a drying oven.

After taking out the furnace and cooling, carefully peel off the tape and paper stuck to the glass substitute surface, taking care not to make the contour lines uneven.

Further, in the case of a shallow-bent or flat plate-shaped organic window glass as a sheet-formed product, the above steps are performed after coating by screen printing as in the case of general glass masking.

Among the above conventional masking coating methods, those that go through the steps of to have a large number of masking steps, resulting in very poor productivity, as well as being skilled in how to attach and paint the tape and how to remove the tape after painting. In short, it is extremely difficult to form a clean parting without unevenness due to poor adhesion between the hard coat surface and the masking agent, and workability is poor. Moreover, there is a problem of peeling of the masking coating film due to poor adhesion between the hard coat surface and the masking agent, resulting in poor production yield.

Although the screen-printing method has good productivity to some extent, the masking coating step still poses a major problem in terms of window glass productivity and cost.

As a solution to such a problem, the present applicant has
For example, as shown in FIGS. 2A to 2G, in a vehicle window glass made of organic glass, a vehicle window glass 10 in which a colored portion 12 is formed on the peripheral portion of a transparent glass portion 11 by a multicolor molding method. Regarding the application for utility model registration,
-150138, hereinafter referred to as the "first application". ).

In the vehicle window glass of the above-mentioned prior application, the colored portion (masking portion) is integrally formed at the same time as the transparent glass portion of the main body by the multicolor molding method, so that the coating process can be completely omitted and the productivity is improved. It can be remarkably increased and a large cost reduction can be achieved. Moreover, since the masking portion is not formed by painting, there is no problem such as peeling of the coating film and the durability is good.

[Problems to be Solved by the Invention] However, when a colored portion is formed on the peripheral portion of the transparent glass portion by a multicolor molding method, there is a problem that it is difficult to obtain a product having a shape as a mold due to the following reasons. is there.

That is, for example, in the case of two-color molding, the deformation at the time of mold release occurs due to the difference in shrinkage between different materials such as the primary molding material, the secondary molding material, and the shrinking time difference due to subsequent cooling of the secondary molding portion.

Since the residual internal stress is large, deformation occurs during post-treatment such as baking of the hard coat.

In particular, in the case of a design in which the thickness of the primary molding portion and the thickness of the secondary molding portion are desired to be different, warp or distortion occurs in the product due to the sink mark and the contraction difference due to the thickness difference, and the mold shape retention is poor. For example, a vehicle window glass as shown in FIG.
In the case of 10, deformation occurs as shown in FIG. 5 (a) or (b), and perspective distortion occurs due to the sink mark at the boundary V between the transparent glass portion 11 and the colored portion 12.

Furthermore, since a 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 coat process depending on the resin used and the hard coat agent. There is also a drawback that the coating conditions are limited.

[Means for Solving the Problems] In the method for manufacturing a vehicle window glass of the present invention, in manufacturing an organic glass vehicle window glass having a colored portion at a peripheral portion of a transparent glass portion by a multicolor molding method, A method of injection-molding a transparent glass part first and then a colored part, wherein at least the transparent glass part is injection-molded 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 basically complies with the conventional method, but the mold design structure and molding conditions for obtaining the quality as an organic glass window material for vehicles should be appropriately set. Is preferred. Further, in the present invention, when manufacturing a vehicle window glass by injection molding by a multicolor molding method,
The transparent glass part is molded first, and then the colored part is molded.

Therefore, in the method of the present invention, in the multicolor molding, at least the injection molding of the transparent glass portion is performed by the injection compression molding.

In practicing the present invention, for example, a compression step is added to multicolor molding using a reversing table which is generally performed in the past. In this case, the compression step is at least the transparent glass portion of all injection molding. It may be adopted for molding, but more than that, for example, the compression step may be adopted for all injection molding.

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

 Compression is applied to both the primary and secondary sides.

Any of these can be adopted.

Since the transparent portion of the window glass is normally on the primary molding side, at least the primary side is compressed. The injection compression method is not particularly limited, and is determined according to the size of the molded product and the like.

For example, in the case of a relatively small molded product, the thickness of the molded product is 5
A molding method in which a resin is filled up to the end of the mold while maintaining a compression margin of -10% is preferable. In this case, the compression method is
Either an oil block system or a machine block system may be used.
Alternatively, a so-called two-stage mold clamping method can be adopted in which the mold clamping pressure is reduced to a low level, the mold is clamped before injection, and the movable mold is retracted by the injection pressure to obtain the compression margin without providing a compression allowance in advance. .

On the other hand, in the case of a relatively large molded product, the resin is difficult to flow sufficiently in the mold, and therefore, as shown in FIG. 1 (a), the compression allowance d is increased in advance with respect to the thickness D of the molded product. It is preferable to adopt the method of leaving a gap.

In the case of the above-mentioned relatively small molded product, in which the resin is sufficiently flowable, the resin is filled up to the end of the mold when injection is completed, whereas in such a relatively large molded product, the resin is If the material cannot be sufficiently flowed in the mold, the mold 2 is usually used at the completion of injection as shown in FIG. 1 (a).
The resin 20 has not reached the ends of 1 and 22. However, even in this case, since the flow path is widened by the compression allowance d, the fluidity of the resin is improved. Therefore, the resin 20 injected from the nozzle 21a is released to the atmospheric pressure.
Since the resin can flow and reach the end of the mold until it cools and solidifies, by compressing the resin before it solidifies by cooling, as shown in FIG. 1 (b),
A molded product that is thin and has a uniform molding pressure can be obtained. Therefore, in the case of a large-sized molded product, it is advantageous to adopt such a method.

In addition, it is easier and more advantageous in terms of equipment to provide such an injection compression process on the primary injection side than the reverse side of the other color molding.

2 (a) to (g) are schematic cross-sectional views showing an example of a vehicle window glass manufactured by such a 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. 2A to 2G, the periphery of the transparent glass portion 11 is colored by a multicolor molding method. The part 12 is formed.

In the present invention, the colored portion 12 to be formed is the peripheral portion of the window glass 10, and the sectional shape of the colored portion is not particularly limited.

For example, as shown in FIGS. 2A to 2C, 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 surface side of the window glass. In the case of the structure shown in FIG. 2D, the colored portion 12 is covered with the transparent glass portion 11, so that the colored portion
A beautiful crystal feeling is added to 12. The colored portion 12 is not limited to the case where the colored portion 12 is provided flush with the transparent glass portion 11 as shown in FIGS. 2A to 2D, but is not limited to the case where the colored portion 12 is provided as shown in FIGS. 2E to 2G. It may be provided such that all or all of them are projected from the transparent glass part 11. The shape and the like of the colored portion 12 can be easily set by changing the mold design structure.

In the present invention, as the transparent glass material, a thermoplastic resin such as polycarbonate, acrylic resin, ABS (acrylonitrile / butadiene / styrene) resin, AS (acrylonitrile / styrene) resin is preferable because it is easy to mold, It may be a thermosetting resin.

As the material for the colored portion, various colored resins can be used, but those obtained by coloring the resin used as the transparent glass material with an appropriate pigment are compatible with the transparent portion (bondability or adhesiveness during molding or (Integration after molding, etc.) is good and suitable. Of course, other general-purpose resins colored with an appropriate pigment can also be used. As the resin of the colored portion, polyethylene resin, vinyl chloride resin, etc. are generally preferable because they are inexpensive.

The window glass for vehicles manufactured by the present invention is, in addition to the windshields of various vehicles such as cars such as passenger cars and freight cars, trains,
Of course, it can also be applied to rear side glass (triangular window), roof glass, and the like. Besides, it is also applicable to a tail lens and the like. Generally, the size is within 150 cm x 150 cm, but it may be larger than that.

The size of the colored portion to be formed differs depending on the shape and size of the window glass, the purpose of use, the purpose of forming the colored portion, and the like, and is appropriately determined. For example, the thickness of the cross section as shown in FIG. In the case of the windshield 10 having a thickness t = 2 to 8 mm, the size of the colored portion 12 to be formed is the value of a and b in FIG.
= 0.5 to 2 mm and b = 5 to 50 mm.

The window glass for vehicles produced by the present invention may be hard-coated according to a conventional method, in which case there are also problems such as peeling due to poor adhesion between the hard-coat surface and the masking agent and cracks during hard coating. Without it, the hard coat can be applied very well.

2 (a) to (g) and FIG. 4, since the window glass of the present invention is schematically shown, the window glass has a flat plate shape. It goes without saying that it can also be applied to the production of flat window glass.

The multicolor molding method adopted in the present invention can be applied to the formation of marks and decorative windows (garnish) as well as the masking of the periphery of the window glass. In this case, the marks and garnish may be formed with masking around the window glass,
Only the marks and garnish may be formed by a multicolor molding method.

[Operation] In the injection compression method, the resin of the molding material is filled in a state where the mold is pre-opened. Therefore, at the stage of injection and inflow of the resin into the mold, the resin is made to flow more to reach the end of the mold. Can be made. Then, after that, pressure is applied to compress the resin, so that it is possible to obtain a thin-walled molded product that cannot be achieved by ordinary injection molding, and moreover, uniform pressure is applied to the entire surface of the molded product, so that internal residual strain A small number of molded products can be obtained.

Therefore, the shape retention of the molded product is significantly improved.

The sink marks and shrinkage of each part of the molded product become uniform, and the surface accuracy of the molded product improves.

The perspective distortion at the boundary between the transparent glass portion and the colored portion is reduced.

 Generation of cracks in the hard coat is prevented.

And the like.

[Examples] Examples will be described below.

Example 1 Injection compression molding as shown in FIGS. 1 (a) and 1 (b) was adopted on 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). Window glass manufactured.

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

Molding material Transparent glass part: Polycarbonate resin Colored part: Polycarbonate resin (black pigment 0.5% by weight carbon black mixed) Molding condition Injection compression molding allowance d: 0.2cm Molded product shape Vertical: 42cm Horizontal: 23cm Thickness: 0.4cm Colored part (values of a and b shown in FIG. 4) a: 0.2 cm b: 3 cm As a result, the obtained window glass material has good shape retention and is not deformed at the time of mold release or after treatment. It never happened. Further, the perspective distortion at the boundary between the transparent glass portion and the colored portion was also good.

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

Hard coating agent: Silicone thermosetting type (with primer treatment) Treatment condition: 120 ° C, 60 minutes As a result, window glass is not deformed by the hard coating treatment, and cracks may occur near the gate. There wasn't.

[Effects of the Invention] As described in detail above, the method of the present invention requires that the transparent glass portion is first formed when the organic glass vehicle window glass having the colored portion on the peripheral portion of the transparent glass portion is manufactured by the multicolor molding method. A method of injection molding a colored part after injection molding into
At least the transparent glass portion is injection-molded by injection compression molding, and the molding material resin is filled with the mold opened, so that the resin can be filled up to the end of the mold with good fluidity.

Therefore, it is possible to mold a large-sized molded product.

 High viscosity materials can be used.

 Thin wall molding is possible.

 Anisotropy in strength and shrinkage disappears.

 Can be molded at low pressure.

 Can be molded at low temperature.

And the like.

Further, a uniform pressure is applied to the entire surface of the molded product, and a molded product with less internal residual strain is obtained, so that the shape retention of the product is improved.

 Shrinkage and shrinkage are reduced, and perspective distortion is improved.

The problem of crack generation during hard coat treatment is solved.

From the above, the degree of freedom in designing the masking part of the product is increased and the design is improved. And the like.

Therefore, according to the method of the present invention, it is possible to manufacture a window glass for a vehicle which is highly productive, efficient, low cost, excellent in durability, high in performance and beautiful.

[Brief description of drawings]

1 (a) and 1 (b) are partial cross-sectional views of a mold for explaining the method of the present invention, and FIGS. 2 (a) to (g) are examples of vehicle window glass manufactured by the present invention. Schematic sectional view showing the third
The figure is a cross-sectional view explaining the windshield mounting part of the automobile,
FIG. 4 is a schematic cross-sectional view of a vehicle window glass manufactured by the present invention, and FIGS. 5 (a) and 5 (b) are cross-sectional views showing a distortion generating portion of the window glass. 10 ... Vehicle window glass, 11 ... Transparent glass part, 12 ... Colored part.

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Claims (1)

[Claims] 1. When manufacturing an organic glass window glass for vehicles having a colored portion on the periphery of a transparent glass portion by a multicolor molding method, the transparent glass portion is first injection-molded, and then the colored portion is injection-molded. A method for manufacturing a window glass for a vehicle, characterized in that at least the transparent glass portion is injection-molded by injection compression molding.