JPH049648B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for producing a synthetic resin molded product having a hardened film layer on its surface, and in particular to a method for producing a synthetic resin molded product suitable for resin windows for vehicles. It is.

[Conventional technology]

2. Description of the Related Art Synthetic resin molded products that are hardened on both sides and have improved scratch resistance and abrasion resistance are used as synthetic resin molded products for resin windows for vehicles and the like. FIG. 5 is a system diagram showing a conventional manufacturing method for such synthetic resin molded products. The molded product material 1, in which polymethyl methacrylic resin is molded into a predetermined shape using a transparent synthetic resin such as polycarbonate resin, is degreased. It is immersed in tank 2, degreased and cleaned with a cleaning solvent such as normal hexane, and after drying, immersed in hardening treatment tank 3, that is, by depping, flow coating, spraying, etc.
After uniformly applying a treatment solution such as SiO ₂ solution,
A finished product 4 is obtained by drying (baking) and surface hardening. Examples of such methods include, for example, JP-A No. 48-81928, JP-A No. 52-138565, JP-A No. 53-
No. 138476 is known.

However, in all of these methods, the composition for forming the cured film is a solution, and the solution is applied to the molded article to form the film, so they have the following problems.

It requires different processing methods such as resin molding and surface treatment, resulting in poor production efficiency and long production lines.

A solvent cleaning process is required to remove dust, oil, etc. adhering to the surface of the molded product material.

When the molded product is a window, it is necessary to use transparent synthetic resin to allow light to pass through, and if flow marks or weld lines occur on the outer surface of the material, they cannot be covered up even in the finished product. Therefore, it is completely visible and cannot be put to practical use.

When using dipping or flow coating to attach the processing liquid, it takes time to enter and exit the tank smoothly so that no air bubbles remain.

There are restrictions on the shape of the molded product in order to prevent the liquid processing solution from dripping or clumping.

Poor mass production.

[Problem to be solved by the invention]

The object of the present invention is to solve the above-mentioned problems and to propose a method that can easily and efficiently produce a synthetic resin molded article having cured film layers on both sides.

[Means to solve the problem]

In the present invention, two transparent thermoplastic synthetic resin films 5, 5 having hardened film layers 5b, 5b formed on their surfaces are placed in a cavity 11 of an injection mold, respectively.
The bases 5 of the films 5, 5 are placed on both sides of the film 5, and the respective cured film layers 5b, 5b are set in a direction facing different mold surfaces.
After clamping the mold so that a cavity 11 is formed between surfaces a and 5a, heated and molten liquid synthetic resin is injected into the cavity 11 to fill it,
While molding the molded product main body 4a, films 5, 5 having cured film layers 5b, 5b are formed.
This is a method for manufacturing a resin molded product, which is characterized in that the resin molded product is laminated and integrated on both sides of the molded product main body 4a.

In the present invention, the term "film" includes sheets and other similar shapes.

[Effect]

In the method for manufacturing a resin molded product of the present invention, first, two transparent thermoplastic synthetic resin films 5, 5 having cured film layers 5b, 5b formed on their surfaces are placed on both sides of the cavity 11 of an injection mold, respectively. The cured film layers 5b, 5b are set in a direction facing different mold surfaces, and the molds are clamped so that a cavity 11 is formed between the bases 5a, 5a surfaces of the films 5, 5. Then, heated and molten liquid synthetic resin is injected into the cavity 11 to fill the cavity 11 to form the molded product body 4a, and the films 5, 5 having the cured film layers 5b are attached to the molded product body. Both sides of 4a are laminated and integrated to produce a resin molded product.

In this case, the films 5, 5 having the cured film layers 5b, 5b are placed on both sides of the cavity 11 and injection molding is performed, so the films 5, 5 are laminated together at the same time.
5b can be manufactured efficiently, and flow marks, silver, etc. are less likely to occur.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a front view showing a state in which a synthetic resin film with a hardened film layer formed on its surface is vacuum formed, Fig. 2 is an enlarged partial cross-sectional view of the synthetic resin film, and Fig. 3 is a cross-sectional view showing an injection molding state. 4 are cross-sectional views of the finished product. In this example, the finished product 4 of the vehicle window shown in FIG. 4 is manufactured. First, the synthetic resin film 5 shown in FIG. 2 is shaped into a shape that approximates the surface shape of the finished product 4 by the method shown in FIG. Shape. The synthetic resin film 5 has a base 5a made of a transparent thermoplastic synthetic resin such as polymethyl methacrylate resin or polycarbonate resin, and a hardened film layer 5b made of a silicone hard coat or the like is formed on preferably one surface of the base 5a. The method of forming the cured film layer 5b on the film 5 is to apply it directly or as a primer layer on a wide flat sheet of transparent film made of polymethyl methacrylic resin or polycarbonate resin formed to a thickness of about 0.05 to 1.0 mm. After forming, a cured film layer is formed by a known method. A molded product with a complex external shape may be thin, and a flat product may be long, and the actual thickness is about 0.125 to 0.5 mm. In this case, a cured film layer can be formed on the entire surface of a wide film base, and the film can be kept flat, so even if a liquid solution is used to form a cured film layer, local sag etc. will not occur. Without,
It can be formed to have a uniform thickness and smoothness over the entire surface.

The film 5 with the cured film layer 5b formed in this way
is placed above the vacuum forming mold 6 as shown in FIG. Vacuum forming is performed by adhering to the

In this case, two types of molded films 5 are formed: one vacuum-formed with the cured film layer 5b facing the heater 7 side, and one vacuum-formed with the cured film layer 5b facing the mold 6 side.

The film 5 thus formed into a shape approximating the surface shape of the finished product 4 is cut to an appropriate size and then injection molded. That is, in FIG. 3, the films 5, 5 are arranged on both sides of the cavity (gap) 11 formed between the cavity mold 8 and the core mold 9 of the injection mold, and the cured film layers 5b, Set so that 5b faces the cavity mold 8 and core mold 9 sides, respectively, and
The films 5, 5 are sandwiched between the cavity mold 8, the core mold 9 and the slide core mold 9a so that a cavity 11 is formed between the gates 10 and 5a. Insert injection molding is performed by injecting molten liquid transparent resin. The resin injected at this time is preferably a resin that is compatible with the base 5a of the film 5. In particular, if the resin is made of the same material, the surface of the base 5a on the cavity 11 side will melt due to the heat and pressure of the injected resin. This is preferable because they are firmly welded to each other. When the two are not compatible, the cured film layer 5 of the base 5a
It is preferable to form an adhesive layer in advance on the surface opposite to the surface to which b is applied.

The injected resin is filled into the cavity 11 to form the molded product body 4a, and thereby the film 5 having the cured film layers 5b, 5b.
5 is laminated and integrated on both sides of the molded product main body 4a to obtain a molded product.

In this embodiment, since the injected high-temperature molten resin does not directly contact the surface of the cavity mold 8 or the core mold 9, that is, the film 5 serves as a heat insulator, the surface of the cavity mold 8 or the core mold 9 is There is no rapid cooling and solidification on the side, and therefore flow marks and silver are less likely to occur. In addition, since the flow resistance of the resin within the cavity 11 is reduced, the resin can be easily spread to every corner of the cavity 11. Therefore, a low injection pressure is required, and the wall thickness is relatively thin and the area is small. Particularly suitable for manufacturing large windows. Furthermore, weld lines are less likely to occur.

In addition, even if the surface of the molded product is required to have a mirror-like smoothness, such as a window, if the film 5 with a smooth surface is used, the cavity mold 8
Alternatively, a molded product having a smooth outer surface close to a mirror surface can be obtained without mirror finishing the nine surfaces of the core mold.

That is, when heated and melted liquid resin is injected and filled into the cavity 11, the heat of the resin softens the film 5, but the hardened film layer 5b arranged on the side facing the mold surface of the film 5 maintains its rigidity. Therefore, even if there are microscopic irregularities on the mold surface, the irregularities are not transferred to the cured film layer 5b, and the cured film layer 5b maintains a mirror surface. Therefore, there is no need to mirror-finish the mold surface, and manufacturing costs are reduced.

The molded product thus formed is taken out by opening the cavity mold 8 and core mold 9 of the metal mold, and the necessary portions are trimmed to obtain the finished product 4. As shown in FIG. 4, the finished product 4 has a molded product body 4a made of transparent resin.
and the films 5, 5 are closely joined and integrated,
It has cured film layers 5b, 5b on both sides, and is completed as a molded product with improved scratch resistance and abrasion resistance.

In addition, when molding the film 5 by injection molding,
Directly using the cavity mold 8 and core mold 9, in other words, the film may be slightly softened by the heat of the injected resin and plastically deformed to conform to the mold surface. In particular, the molded product may have a stepped or uneven surface. If the amount of molded product is small, it is possible to omit vacuum forming and directly set the film in a mold to produce a predetermined molded product. In addition to vacuum forming, the film 5 can also be formed by hot pressing or other methods.

This invention is applicable not only to vehicle windows but also to synthetic resin molded products for other uses, such as windows and lenses for buildings, and transparent covers for office automation equipment.

〔Effect of the invention〕

As described above, the present invention provides the following effects.

Since a film with a hardened film formed on the surface is bonded, the process is shorter than the conventional direct processing of molded products.

No pre-treatment of the molded product material is required.

Great for mass production.

Quality improves.

Improved design freedom.

Partial processing is possible.

[Brief explanation of drawings]

Fig. 1 is a front view showing the state of vacuum forming the film, Fig. 2 is a sectional view of the film, Fig. 3 is a sectional view showing the injection molding state, Fig. 4 is a sectional view of the finished product, and Fig. 5 is a sectional view of the film. FIG. 2 is a system diagram showing a conventional manufacturing method. In each figure, the same reference numerals indicate the same or equivalent parts, 1 is the molded product material, 4 is the finished product, 4a is the molded product body, 5 is the film, 5a is the base, 5b is the cured film layer, and 6 is for vacuum forming. mold, 7 is a heater, 8 is a cavity mold, 9 is a core mold, 10 is a gate, 11
is the cavity.

Claims (1)

[Claims] 1. Two transparent thermoplastic synthetic resin films 5, 5 having cured film layers 5b, 5b formed on their surfaces,
They are placed on both sides of the cavity 11 of the injection molding mold, and the respective cured film layers 5b, 5b are set in a direction facing different mold surfaces, and the base 5 of the films 5, 5 is
After clamping the mold so that a cavity 11 is formed between surfaces a and 5a, heated and molten liquid synthetic resin is injected into the cavity 11 to fill it,
While molding the molded product main body 4a, films 5, 5 having cured film layers 5b, 5b are formed.
A method for producing a resin molded product, which comprises laminating and integrating on both sides of a molded product main body 4a.