JPS63287579A - Production of polycarbonate resin molded article with surface partially hardened - Google Patents

Abstract

PURPOSE:To facilitate the partial surface hardening of the title polycarbonate resin molded article by heat-curing a silicone-based hard-coat agent coated on the molded article surface having a partial releasable paint coated film, and then releasing the releasable paint coated film. CONSTITUTION:A masking tape 2 is stuck on the surface of a polycarbonate resin molded article 1, and a releasable paint is then coated thereon to form a releasable paint coated film 3. A silicone-based hard-coat agent 4 is coated on the surface of the molded article 1, the coated film is heated at a specified temp. for a specified time, and the film is heat-cured. The film is then cooled by natural cooling, etc., and the releasable paint coated film 3 is released. The silicon-based hard-coat agent 4 on the coated film 3 is also released along with the coated film 3, and a polycarbonate resin molded article 10 having a beautiful borderline 4a and with the surface partially hardened can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a partially surface-hardened polycarbonate resin molded product, which can be particularly well coated with a blackout coating as an automobile window material. A method for producing a partially surface-cured polycarbonate resin molded article is described.

[Prior Art] When polycarbonate resin molded products are used as automotive window materials, surface hardening treatment is essential in order to improve scratch resistance, weather resistance, and chemical resistance. A thermosetting method is one of such surface hardening treatment methods.

The thermosetting method is a method in which a hard coating agent is applied and then heated to cause a polycondensation reaction to form a cured film.The coating agents used include silicone, melamine, urethane, and fluorine-containing coatings. ing. Among these, silicone thermosetting hard coating agents are particularly effective in terms of scratch resistance, weather resistance, and chemical resistance, and are practical in terms of cost.

Incidentally, automobile window materials are often attached to the body with adhesive, and for this purpose blackout painting of the peripheral portions is required.

There are two possible procedures for applying blackout painting: one is to apply blackout painting after hard coat treatment, and the other is to apply hard coat treatment after blackout painting.In the latter method, blackout occurs when applying hard coat agent. This is impossible because the paint film will dissolve. On the other hand, in the case of the former, there are colored paints and adhesives that have good adhesion to hard coating agents for acrylic resin molded products (usually acrylate hard coating agents), but these are best suited as hard coating agents for polycarbonate resin molded products. Silicone-based hard coating agents generally have poor adhesion with paints and adhesives, and urethane-based black paints have particularly poor adhesion. Currently, there are no paints or adhesives that have good adhesion to silicone hard coat films, so it is difficult to apply paint with good adhesion to silicone hard coat films. Beforehand, physical surface treatments such as sandpapering and sandblasting are applied, and after removing the hard coat film from the area to be painted, blackout painting is performed.

[Problems to be Solved by the Invention] However, with physical surface processing methods such as sand vapor coating and sandblasting, it is technically extremely difficult to remove only the desired areas of the hard coat film, and it requires advanced skills and long periods of time. Processing time is required, and the high-precision processing generally makes it impossible to create clear paint separation lines.

For this reason, there has conventionally been a problem in that painting treatments such as blackout painting cannot be efficiently performed on polycarbonate resin molded articles that have been subjected to hard coat treatment and in a good finished state.

[Means for Solving the Problems] The present invention applies a silicone hard coating agent to the surface of a polycarbonate resin molded product that has a peelable paint film formed by applying a peelable paint to a part of the surface. The gist is a method for manufacturing a partially surface-hardened polycarbonate resin molded article, which comprises applying the hard coating agent, thermally curing the hard coating agent, cooling it, and then peeling off the peelable paint film. be.

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

FIGS. 1(a) to 1(f) are cross-sectional views illustrating a method of manufacturing a partially surface-hardened polycarbonate resin molded article according to the present invention.

In the present invention, first, a peelable paint is applied to a part of the surface of a polycarbonate resin molded article.

When applying the peelable paint, as shown in Figure 1(a), masking tape (paper tape with adhesive) 2 is pasted on the surface of the polycarbonate resin molded product 1, and then the peelable paint is applied. Forming a peelable paint film 3 (first
Figure (b)).

The peelable paint uses a solvent that does not attack the polycarbonate resin molded article 1, is not attacked by the silicone hard coating agent in the subsequent process, and is able to withstand the heat of the thermosetting process. Generally, water-soluble acrylic paints are preferred.

If the peelable paint film 3 is too thick or too thin, it will not be possible to form a good parting line. In general,
The thickness of the peelable paint film 3 is preferably about 20 to 40 μm.

Next, as shown in FIG. 1(C), a silicone hard coating agent 4 is applied to the entire surface of the polycarbonate resin molded product 1. As a method for applying the silicone hard coat agent 4, all commonly known methods such as dipping, flow coating, spin code, bar code, spray coating, etc. can be applied.

After applying the silicone hard coating agent 4, the coating film is heated at a predetermined temperature for a certain period of time to be thermally cured. The thickness of the coating film of this silicone hard coating agent 4 is determined depending on the purpose of use of the polycarbonate resin molded product, etc., but in general, the coating film thickness after curing is about 2 to 10 μm. preferable.

In addition, when applying the silicone hard coat agent 4, it is preferable to perform pretreatment such as degreasing and cleaning the surface of the polycarbonate resin molded product with isopropyl alcohol or the like. Film thickness of plastic acrylic resin paint, etc. is 2
After coating and drying to a thickness of about 8 μm, it is preferable to apply the silicone hard coat agent 4.

After the silicone hard coating agent 4 is applied and thermally cured, it is cooled (for example, naturally cooled), and then the peelable paint film 3 is peeled off. As a result, together with the peelable paint film 3,
The silicone hard coating agent 4 on the peelable paint film 3 is also removed, yielding a partially surface-hardened polycarbonate resin molded article 10 having a beautiful border line 4a.

When applying a colored paint to the non-surface hardened portion of the partially surface hardened polycarbonate resin molded article 1o obtained in this way, first, as shown in FIG.
Masking tape (paper tape with adhesive) 5 along a
, and then apply colored paint 6 by spraying or the like.

Finally, when the masking tape 5 is peeled off, as shown in Figure 1(f), the parting line 7 between the hardened surface area (section 4 in the figure) and the colored area (section 6 in the figure) is very beautiful. product is obtained.

In addition, in FIG. 1(e), instead of the masking tape 5, a mask plate matching the shape of the surface hardened portion (portion 4 in FIG. 1(e)) may be brought into contact.

[Function] In the method of the present invention, a polycarbonate resin molded product on which a peelable paint film is formed is hard coated in areas that do not require hard coat treatment, and then the peelable paint is peeled off. It is possible to easily and efficiently obtain hard-coated polycarbonate resin molded products.
The border line of the hard coat treated area is also extremely beautiful.

With such partially surface-hardened polycarbonate resin molded products, it is possible to directly apply colored coating to areas without a hard coat film, and use a paint with good adhesion to create a good colored coating. can be formed. Moreover,
The boundary line of the hard coat treated area is beautiful and the coating film forming properties such as the adhesion of the colored coating film are also good, so extremely beautiful parting lines can be formed by masking coating or the like.

[Examples] Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples, and Reference Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Example 1 An automobile window material was manufactured from a polycarbonate resin molded plate (a=600 mm, b=850 mm) whose planar shape is shown in FIG.

First, the second part is the part where the blackout coating is formed.
Apply 20 to 40 μm of water-soluble acrylic peelable paint (Toshiba Electric rJD-P5J or rJD-P4) to part A in the diagram.
Masking coating was applied to a thickness of m. Note that the widths Wl to w5 of each part of the portion A in FIG. 2 are as follows.

WI=W4-W5=50 mm w2w40mm w3z70mm Next, after degreasing and cleaning the surface of the forming plate with isopropyl alcohol, a primer for silicone hard coating agent (
After curing, apply a thermoplastic acrylic resin paint (thermoplastic acrylic resin paint) to a film thickness of 2 to 5 μm after curing.
After 5 minutes, it was dried with hot air at 120 tons for 30 minutes. Furthermore, a silicone hard coating agent (Toshiba Silicone Co., Ltd. "Toss Guard 510J") was applied by dipping to a film thickness of 5 to 8 μm after curing, and the coating was applied at a setting of 15 at a humidity of 48%.
After a few minutes, it was heated and cured at 120° C. for 60 minutes. After cooling naturally for about 15 minutes, the strippable paint film was peeled off. the result,
A molded plate was obtained in which only the portion B in FIG. 2 was surface hardened.

Furthermore, a black paint (Kansai paint group, 2-component urethane paint) was sprayed on the A part of this molded plate to a film thickness of 1 after curing.
Masking coating was applied so that the thickness was 0 to 15 μm, and the film was cured by heating at 80° C. for 30 minutes.

As a result, an automobile window material was obtained in which the part A in FIG. 2 had a blackout coating and the part B had been surface hardened, and the parting line of the blackout coating was extremely beautiful.

Comparative Example 1 After degreasing and cleaning the surface of the polycarbonate resin molded plate used in Example 1 with isopropyl alcohol, a primer for the silicone hard coat side was applied in the same manner as in Example 1.
Next, a silicone hard coat agent was applied and cured by heating.

Thereafter, the black paint used in Example 1 was spray-masked onto the portion corresponding to A in FIG. 2, and the black paint was cured by heating at 80° C. to give a blackout coating.

As a result, the window material obtained had sawtooth-like parting lines of the blackout coating, and was not beautiful.

The reason for this is that the adhesion between the black paint and the silicone hard coating film is not good, so when the masking tape is removed after masking, the black paint adheres to the tape side, and the black paint adheres to the edge of the masking tape. This is because a good straight cut surface cannot be obtained.

Comparative Example 2 In the same manner as in Comparative Example 1, a silicone hard coat side primer and a silicone hard coat agent were applied and cured by heating.Then, the area corresponding to A in Figure 2 was sanded with sandpaper (#600). After cleaning this surface with isopropyl alcohol, blackout coating was applied in the same manner as in Comparative Example 1.

As a result, the parting line of the blackout coating was slightly serrated, and a beautiful parting line could not be obtained.

Reference Example 1 When the polycarbonate resin molded plate used in Example 1 was coated with rTBX-1200J manufactured by Three Pond in a masking manner in the area corresponding to A in Fig. 2, the surface of the polycarbonate resin molded plate was eroded and white turbidity occurred. Ta.

This is because although it is rTBX-120OJ&t7ri'), it is not water-soluble and uses something like a ketone as a solvent, and this solvent corrodes the polycarbonate. Therefore, such paints are not suitable as the peelable paints of the present invention.

Reference Example 2 An attempt was made to manufacture a window material in the same manner as in Example 1, except that Asahipen's "Clean Back" was used as the peelable paint.

As a result, the peelable paint film was dissolved in the solvent of the silicone-based hard coat side primer and could not be peeled off, making blackout coating impossible.

Although the "clean back" is made of acrylic,
This is presumed to be because it is not water-soluble, and is therefore not suitable as a peelable paint.

[Effects of the Invention] As detailed above, according to the method of manufacturing a partially surface-hardened polycarbonate resin molded product of the present invention, ■ a product whose surface is partially hardened easily in a short time without the need for sanding treatment; can be obtained, improving manufacturing efficiency.

■ Peelable paints can be reapplied any number of times and are easy to apply, so they can be suitably applied to molded products with complex shapes and products with complex surface hardened and non-surface hardened parts. can.

■ The boundary line between the surface hardened area and the non-surface hardened area is beautiful.

Effects such as these are produced.

The partially surface-hardened polycarbonate resin molded article produced by the method of the present invention can be coated with a colored paint such as black paint on the non-surface-hardened portion with good adhesion, and as described above, the surface-hardened portion and the non-surface-hardened portion can be coated with a colored paint with good adhesion. Since the border line is beautiful and the adhesion of the colored paint is good, it is possible to apply a colored coating with a beautiful parting line by masking painting or the like. The method of the present invention is extremely effective for manufacturing automobile window materials that require surface hardening treatment and blackout painting.

[Brief explanation of drawings]

FIG. 1 is a sectional view illustrating an example of the method of manufacturing a partially surface-hardened polycarbonate resin molded article of the present invention. FIG. 2 is a plan view showing an automobile window material manufactured in an example. DESCRIPTION OF SYMBOLS 1... Polycarbonate resin molded article, 3... Peelable paint film, 4... Silicone hard coating agent, 6... Colored paint, 7... Parting line.

Claims (5)

[Claims] (1) On the surface of a polycarbonate resin molded product, a part of the surface is coated with a peelable paint to form a peelable paint film.
A method for producing a partially surface-hardened polycarbonate resin molded article, which comprises applying a silicone hard coat agent, heat curing the hard coat agent, cooling it, and then peeling off the peelable paint film. . (2) The method according to claim 1, wherein the polycarbonate resin molded product is coated with a primer for a silicone hard coat agent, and then a silicone hard coat agent is applied. (3) The method according to claim 1 or 2, wherein the peelable paint is a water-soluble acrylic paint. (4) The method according to any one of claims 1 to 3, wherein after removing the peelable paint film, a paint is applied to the peeled surface. (5) The method according to claim 4, wherein the paint is a urethane black paint.