JPS61118209A - Liquid resin mold - Google Patents

Abstract

PURPOSE:To prevent a glass template from breaking and to offer a platelike molded article whose thickness accuracy is high, by a method wherein the titled mold is so constituted that a rigid spacer made of a synthetic resin-laminated material having a constant thickness is used and sealing properties are obtained by an elastic spacer made of silicon rubber adjoining to the rigid spacer. CONSTITUTION:Silicon rubber spacer 3 is arranged within a spacer 2 made of a synthetic resin-laminated material with which a base material is mixed in a state touching internally to the spacer 2. Bonding between resin through which cast molding is performed and the spacer 2 is prevented by inscribing the silicon rubber spacer 3 to the spacer 2 made of the synthetic resin-laminated material with which the base material is mixed. As the spacer 2 is made of the synthetic resin-laminated material with which the base material is mixed, there is no fear of breaking a glass template at all through difference of expansion, contraction and heat capacity as compared with a spacer made of metal, moreover, the spacer 2 is easy to process and dimensional accuracy is quite easily obtainable. In addition to the above, as the silicon rubber spacer 3 is very little thicker than the spacer 2, the spacer 3 is smashed up to the thickness of the spacer 2 when the spacer 3 is clamped, and air tightness is kept on by adhering closely a top force 1 and bottom force 1' to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention is a mold for molding an optical disk substrate by cast molding of a liquid resin, using a rigid spacer made of a synthetic resin laminate having a certain thickness, Furthermore, the present invention relates to a liquid resin mold that provides sealing performance with an adjacent elastic spacer made of silicone rubber, improves the thickness accuracy of the optical disk substrate, and further prevents damage to the mold plate.

[Prior art] Conventionally, a liquid resin mold for molding a thick plate-shaped cast product typically has a structure as shown in Fig. 3, in which the mold is sandwiched between an upper mold 1 and a lower mold 1. The upper mold 1 and the lower mold 1' are fastened together by a screw 5 to form a cavity 4 for obtaining a plate-shaped cast product. A resin is injected and heat treatment (sometimes pressure treatment is also performed at the same time) is performed to obtain a plate-shaped cast product.

In the conventional method, as seen in Japanese Patent Application No. 59-82046 entitled "Liquid Resin Molding Mold," a partially inserted metal piece spacer is used as the rigid spacer.

When a mirror surface and high surface precision are required, such as an optical disk substrate, plastic plates are very often used as the upper and lower molds.

In addition, most of the spacers used are metal, and metal round bars are also often used because they are easy to process and achieve dimensional accuracy.In this case, the contact area between the upper and lower molds is Line contact.

In such a contact structure, when tightening the upper mold and the lower mold with the fastener 5 shown in Fig. 3, depending on the position, if the axes of the clamping jig 5 and the spacer 8 are misaligned, it may be necessary to tighten the lath plate. There is a risk of damage and it will not be possible to tighten uniformly.

Furthermore, a metal spacer with a rectangular cross section may be used, but in this case, differences in expansion, contraction, and heat capacity between the mold constituent members that occur during the process of injecting liquid resin into the mold 4 and performing heat curing treatment. This has the drawback that it causes damage to the glass template, and if scratches occur, the thickness accuracy of the plate-shaped molded product decreases.

When the above-mentioned resin is pressurized during heat curing, the above-mentioned drawbacks become even more noticeable.

However, damage to the positive mold plate and reduction in thickness accuracy will result in extremely poor productivity as well as the characteristics of the optical disc substrate.

OBJECTS OF THE INVENTION The present invention overcomes the drawbacks of the prior art. f? The present invention has been completed through various research aimed at providing a plate-shaped molded product with high thickness accuracy while preventing damage to the mold plate.

[Configuration 1 of the Invention An embodiment of the present invention will be described below with reference to the drawings.

Fig. 1 is a top view showing a schematic structure of a mold member of a mold for molding a liquid resin for molding a disc-shaped cast product, and Fig. 2 is a cross-sectional view taken along the line A-A' in Fig. 1. be.

The upper mold 1 and the lower mold 1 are glass plates with a thickness of 6 to 10 I++m, and since the surface condition is directly transferred to the surface of the molded product, the surface roughness must be less than o and oos μ- in Ra. is desirable.

Further, a base spacer 2 made of a synthetic resin laminate material mixed with a base material is provided between the upper mold 1 and the lower mold 1'.

The material of the spacer spacer 2 is a phenolic resin laminate molded product mixed with a base material that provides rigidity that is less deformed by force when heated or tightened.The thickness accuracy is processed within the required thickness accuracy of the molded product, and the upper mold In order to increase the contact area between the mold 1 and the lower mold 1, a mold having a width of 5 to 30 mm is used.

The shape of the spacer is determined by taking into account the shape of the molded product, the specifications of the silicone rubber spacer 3 described later, the shape of the pressure 11t15, etc.

A silicone rubber spacer 3 is arranged inside a spacer 2 made of a synthetic resin laminate mixed with a base material so as to be inscribed in the spacer.

That is, by inscribing the silicone rubber spacer 3 into the spacer 2 of the synthetic resin laminate material mixed with the base material, adhesion between the resin to be cast molded and the spacer 2 is prevented.

Furthermore, the thickness of the silicone rubber spacer 3 is set to be, for example, o,
oos~0.5m - By increasing the thickness, the sealing performance of the mold can be improved and resin leakage can be prevented.

Next, as shown in FIG. 2, the upper mold 1 and the lower mold 1' are tightened with a clamping jig 14c5 until they come into contact with the spacer 2 made of the synthetic resin laminate material mixed with the base material.

When tightened in this manner, the upper mold 1 and the lower mold 1' and the spacer 2 are in plane contact with each other, so there is little variation in the gap between the upper mold 1 and the lower mold 1, and the tightening is performed so that the axis of the soldier 5 is aligned with the spacer 2. Upper mold 1 and lower mold 1° unless deviated from spacer 6.
There is little risk of damage.

In addition, since the spacer is a synthetic resin laminate mixed with a base material, there is no risk of damaging the glass template due to expansion, contraction, or differences in heat capacity compared to metal spacers, and it is also easier to process ( Dimensional accuracy is also very easy to achieve.

The silicone rubber spacer 3 is very slightly thicker than the spacer 2, so when it is tightened, it is crushed to the thickness of the spacer 2, and comes into close contact with the upper mold 1 and the lower mold 1° to maintain airtightness.

That is, a cast molding cavity 4 is formed inside the silicone rubber spacer 3 and sealed.

Liquid resin is injected into the cast molding cavity 4 formed as described above through a hole, that is, a date roller, previously formed in the upper mold 1.

Incidentally, the vent hole 6 is a hole previously formed in the upper mold 1, similar to the date troller, and is used to remove air from the cast molding hole 4 when injecting resin.

After injecting the resin, the entire casting mold is heated to harden the resin.

When the liquid resin was cast using the liquid resin casting mold thus obtained, a molded product could be obtained without damaging the plastic plate.

Furthermore, when the thickness of the obtained molded product was measured, it was found that the thickness accuracy was significantly improved compared to a molded product using partial metal piece spacers 8 used in the conventional method.

Although only one embodiment of the present invention has been described above, the present invention is not limited to this, and includes applied examples and modified examples of the pond unless the gist of the present invention is changed.

[Advantageous Effects of the Invention 1] As explained above, according to the present invention, a molded product can be obtained without damaging the glass plate, so that the cost of the molded product can be reduced.

Moreover, it was possible to provide a molded product with higher thickness accuracy than molded products using conventional cast molding molds.

[Brief explanation of the drawing]

FIG. 1 is a top view of a liquid resin molding mold of the present invention, and FIG. 2 is a sectional view taken along line AA' in FIG. FIG. 3 is a sectional view of a conventional liquid resin mold. In the figure: 1,1゛ Upper and lower molds made of gamma lath, 2 Laminated material spacer mixed with base material, 3 Silicone rubber spacer, 4 Cavity, 5 Compressor, 6
Ventro, 7 Dedro. 8 Metal rod spacer, 9 Elastic spacer. Patent applicant Sumitomo Bakelite Co., Ltd. Figure 1A Figure 2 Figure 3

Claims (1)

[Claims] In liquid resin casting molds for plate-shaped products consisting of an upper mold, a lower mold, and a spacer sandwiched between them, the mold is made of a synthetic resin laminate mixed with a base material and deforms due to heating, pressure, and fastening force. A mold for molding a liquid resin, which is characterized by comprising a rigid spacer with low rigidity and a silicone rubber spacer with large deformation under pressure and excellent airtightness.