JPS5816811A - Mold for molding and manufacture of resin molded article by using said mold - Google Patents

Abstract

PURPOSE:To obtain a mold for molding by which deflashing is unnecessary and the thin resin molded article of high precision is furnished, by providing the boundary part of a specified width and a groove around a cavity for molding provided on a metal plate. CONSTITUTION:A mold for molding is obtained by providing the boundary part 3 of a width less than 100mum around a cavity 2 for molding provided on a metal plate 1 and providing the groove 4 with a width larger than 300mum around said part 3. After the cavity 2 of the mold has been filled with powdery, granular or pellet like thermoplastic resin 5, the upper part of the mold is covered with a press plate 6 and it is heated to a melting temperature of the resin 5 under applicationof a pressure lower than 5kg/cm<2>. After the cavity 2 has been filled with the molten resin 5 and also it has been made to flow into the inside of the groove 4, passing a clearance between the press plate 6 and the boundary part 3, the press plate 6 is pressurized under a pressure higher than 30kg/cm<2>, the resin 5 is cooled and solidified in the state where the molten resin having flown into the groove 4 is separated at the boudnary part 3 and the resin molded article 7 free of a flash is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for manufacturing a molded article, and is particularly aimed at manufacturing a resin molded article that is thin and requires high precision through a simple process.

Conventionally, methods for producing five resin acids include (1) injection molding method, (2) cast molding method, (2) press molding, and (2) punching method. However, in these molding methods, there is a lower limit to the thickness of the molded product in method (2), and it is difficult to create a molded product with a thickness of 100 μm or less, and in method (2), the volume shrinkage rate of the molded product is It is unsuitable for producing mature products that require high precision. Method (■) leaves particles on the molded product after molding and requires a deburring process. Method (■) does not allow the material to be made into a thin elastomer film. There were drawbacks such as limited production and poor processing accuracy.

The inventors of the present invention have attempted to improve the various drawbacks of the conventional methods as described above, and as a result of various research and considerations, they have completed the present invention. That is, the present invention provides a molding die in which a molding recess 2 is provided in a metal plate 1, a boundary portion 5 with a width of 100 μm or less is provided around the recess 2, and a groove 4 with a width of 200 μm or more is further provided around the boundary portion 5, and After filling the molding recess 2 of the mold with thermoplastic resin 5 in the form of powder, granules, or pellets, the upper part of the mold is covered with a press plate 6 and a pressure of 5 kqA or less is applied. Heating at a temperature at which the plastic resin 5 melts,
This method of manufacturing a resin molded product is characterized in that the press plate 6t is then cooled while applying a pressure of 80 &vd or more to solidify the molten resin.

The present invention will be explained in more detail below based on the drawings.

First, the molding die according to the present invention will be explained (first
．． (See Figure 2). The metal plate 1 used in the mold is made of stainless steel, copper, etc., and its thickness is appropriately selected.

A molding recess 2 is provided in the metal plate l. The four molding parts 2 are for filling with lid fat to obtain a molded product. A boundary portion 3 is provided around the four molding portions 2, and a groove 4 is further provided around the boundary portion 3. The width of boundary part 3 is 100μm
It is preferably 50 μm or less. The width of the groove 4 is 200 μm or more.

Next, a method for manufacturing a resin molded article according to the present invention will be explained. First, the molding recess 2t of the molding die is filled with thermoplastic resin 5 in the form of powder, granules, or pellets, and then the upper part of the mold is covered with a press plate 6 (see FIG. 8).

Examples of the thermoplastic resin used include polyethylene terephthalate, polyether sulfone, polyphenylon oxide, polyurethane, nylon, fluororesin, polyvinyl chloride, polyethylene terephthalate elastomer, and polyurethane elastomer.

Next, the mold is heated while applying pressure to the press plate 6.

The pressure is below 5ktiM. Heating is performed at a temperature at which the thermoplastic resin 5 melts. In the case of the above example, heating may be performed within a temperature range of approximately 159° C. to 850° C. The thermoplastic resin 5 melted by this heating fills the molding recess 2 and further flows into the groove 4 through the gap between the press plate 6 and the boundary 6. After that, 80kl was added to press board 6.
A pressure of i/d preferably 50 mm or more is applied, and the molten resin is solidified by cooling in this pressurized state (see Fig. 4).

During solidification, since the resin is in the pressurized state, the solidified resin can be obtained in the molding recesses, and the resin molded product 7 can be obtained. That is, since the molten resin that has flowed into the groove 4 is separated and solidified at the boundary portion 3, only the solidified portion can be separated and obtained into the four molding portions 2. If a thermoplastic resin with high viscosity is used, the molding recess 2 and the groove 4 may connect and solidify, but since the width of the boundary 6 is narrow, the solidified resin in the groove 4 can be easily removed. (See Figure 5).

Since the present invention is a mold for molding and a method for manufacturing a resin molded product as described above, by applying the mold and the method for manufacturing a resin molded product according to the present invention, it is possible to eliminate the need for the process of removing lipari. A resin molded product can be obtained. Furthermore, since powdered resin is used and melted, it is suitable for producing thin molded products and resin molded products that require high precision. Therefore, the present invention is a molding mold suitable for producing molded products such as watch gaskets, precision filters for electronic parts, various thin gears, sealing materials, etc., and an iM manufacturing method for resin molded products, and has industrial value. It's expensive.

[Brief explanation of the drawing]

1 and 2 show a plan view and a sectional view, respectively, of an embodiment of a molding die according to the present invention. FIG. 3, FIG. 4, and FIG. 5 each show a schematic diagram of each step of the method for manufacturing a resin molded article according to the present invention. In the figure, 1...Metal plate 2...Molding recess 3.
... Boundary portion 4 ... Groove 5 ... Thermoplastic resin 6 ... Press plate 7 ... Resin molded product Patent applicant Nissha Printing Co., Ltd. Figure 1 Figure 2 Figure 4 Figure 69-

Claims (1)

[Claims] 1. A molding recess is provided in a metal plate, and a width of 100 mm is provided around the recess.
Provide a boundary of μm or less, and further have a width of 200 μm around it.
A molding die characterized by having a groove of m or more. 2. Provide four parts for molding on a metal plate, and make a width of 100mm around it.
Provide a border of 1m or less, and a width of 200μ around it.
Powder,
After filling the thermoplastic resin in the form of granules or pellets, the upper part of the mold is covered with a press plate and heated at a temperature at which the thermoplastic resin melts while applying a pressure of 6 kg/d or less, and then A method for manufacturing a resin molded product, characterized in that the press plate E is cooled while applying a pressure of 80 kQ/cd or more to solidify the molten resin.