JPH07306B2 - Curable resin molding manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a curable resin molded product such as an epoxy resin, and more specifically, a flat plate or a flat plate-shaped curable resin having irregularities or protrusions. The present invention relates to a manufacturing method particularly useful for manufacturing a molded article.

(Prior Art) Conventionally, a curable resin molded product such as an epoxy resin has been manufactured by a method such as press molding, transfer molding, injection molding, cast molding, and applied as an industrial member.

This type of curable resin can produce molded products with excellent properties such as transparency, weather resistance, and heat resistance if the resin and curing agent are selected properly. Since molding can be performed in a low-viscosity state, attention has been gained in the field of optoelectronics such as optical discs that require low optical distortion (birefringence).

However, when a molded product having the above characteristics is manufactured using a molding method such as press molding, transfer molding, or injection molding, in any molding method, molding is performed in a state in which the resin is stressed at least. The process of pressurizing the mold because what is to be done, the production capacity of the device is stopped until the injected resin gels, and it is necessary to make the mold follow this contraction as the resin contracts. There are various inconveniences in that Particularly in transfer molding, there is a constraint that the mold must be held under the condition that the plunger pressure is applied.

Furthermore, the casting method in which molding is carried out under normal pressure can produce a molded article having the best characteristics described above, but when air bubbles are mixed in at the time of injecting the resin, or when a thin molded article is produced, However, there is a drawback that it takes time to inject the resin.

(Problems to be solved) Therefore, according to the present invention, by using a curable resin, it is possible to greatly improve workability, obtain a molded product excellent in wall thickness accuracy and optical characteristics, and free from voids. The purpose is to provide a manufacturing method.

(Means for Solving the Problems) According to the present invention, a mold having an injection port at the center and a cavity inside and having an injection port at the center of the cavity is used, and the mold is rotated about the injection port. There is provided a method for producing a curable resin molded article, characterized by injecting a liquid curable resin from the injection port while rotating and curing the resin.

(Operation) In the present invention, since the mold is rotated around the injection port, even if bubbles are mixed during resin injection, the bubbles are concentrated in the injection port at the center of the mold, and as a result, the injection port Gas is degassed from the product, and a void-free molded product can be obtained.

Further, since the centrifugal force acts on the resin filled in the mold, the resin contraction until gelation is captured by the centrifugal force.

(Preferred Embodiment of the Invention) FIG. 1 shows a mold used in the production method of the present invention.

That is, this mold is composed of an upper mold 1 and a lower mold 2, and a cavity 3 is formed in these molds.

An injection port 4 is formed in the center of the upper mold 1,
The curable resin is injected through the injection port 4.

Further, the upper die 1 and the lower die 2 are positionally fixed on the rotary table 6 via the pins 5, and can rotate integrally with the rotary table 6 when the motor 7 is driven. In this case, the mold is fixed in position so that the injection port 4 is located on the rotary shaft 10 of the rotary table 6.

It should be noted that the cavity 3 does not have to have a flat shape as shown in FIG. 1 as long as the spout 4 is formed in the central portion, and may have, for example, an uneven shape.

Thus, according to the present invention, liquid curable resin is injected into the mold from the injection port 4 while rotating the mold.

As the curable resin used, a thermosetting resin known per se such as an epoxy resin, an unsaturated polyester resin, various amino resins, or a prepolymer such as an acrylic resin syrup is used, which is cured depending on the type of resin used. An agent, a curing accelerator, a polymerizable monomer and the like can be combined together.

Further, when the raw material resin has a high viscosity and is difficult to handle, a diluent may be added if necessary.

Further, a coloring agent, a lubricant, a
Of course, it is also possible to mix various known compounding agents such as a filler.

When injecting the cured resin, it is preferable to preheat the mold beforehand. For example, when a combination of an alicyclic epoxy resin and an alicyclic acid anhydride is used, it is usually
It is desirable to heat in the temperature range of 100 to 180 ° C.

The number of revolutions of the mold may be appropriately determined depending on the type of the curable resin as the raw material so that the gas can be effectively released and the resin can be effectively contracted.

According to the present invention, since the resin is injected while rotating the mold, the air bubbles mixed at the time of injection are concentrated in the vicinity of the injection port 4, and as a result, the removal of the air bubbles is promptly performed and the obtained molding is obtained. The product will be completely void free.

In the present invention, the rotation of the mold may be performed for a certain period of time after the injection of the resin, for example, until gelation proceeds to such an extent that the shrinkage of the resin has settled (it usually depends on the type of resin, but is usually about several minutes). It is not necessary to continue spinning until the cure is complete.

Thus, according to the present invention, it becomes possible to effectively prevent the distortion of the molded body due to the shrinkage of the resin.

When the above-mentioned production method of the present invention is applied to a combination of an alicyclic epoxy resin and an alicyclic acid anhydride, a molded product extremely useful for optics can be obtained.

(Example) A mold having a cavity with a clearance of 1.21 mm and 200φ and having an injection port in the center was preheated to 180 ° C., and this was set on a rotary table as shown in FIG.
While rotating at a speed of pm, a resin composition having the following composition was injected.

Formulation Example Alicyclic epoxy resin 1.0 equivalent (Delcel Chemical's Celoxide 2021) 4-methylhexahydrophthalic anhydride 0.8 equivalent (Nippon Rika's RIKACID MH-700) Triphanylphosphine 0.5% by weight per epoxy resin After pouring, continue rotating for 2 minutes, then remove the mold from the rotary table and continue for 5 minutes 18
It was heated to a temperature of 0 ° C. and demolded to obtain a disk-shaped molded product.

The obtained molded product was the most suitable molded product as an optical disc having no voids or optical distortion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an example of a mold for suitably carrying out the method of the present invention. 1 ... Upper mold, 2 ... Lower mold 3 ... Cavity, 4 ... Injection port 5 ... Pin, 6 ... Rotating table 7 ... Motor, 10 ... Rotating shaft

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29K 101: 10 B29L 11:00

Claims (2)

[Claims] 1. A mold having an injection port at the center and a cavity inside and having an injection port at the center of the cavity is used, and the liquid is cured from the injection port while rotating the mold around the injection port as a rotation center. A method for producing a curable resin molded product, which comprises injecting a mold resin and curing the resin. 2. The curable resin is an epoxy resin.
The manufacturing method described in.