JPH07195371A - Production of rubber molded article - Google Patents

Abstract

PURPOSE:To enhance productivity by enhancing the take-out workability of a rubber molded article obtained by molding a rubber compsn. by a mold having male and female molds. CONSTITUTION:A rubber compsn. is molded in an unvulcanized state, a semi- vulcanized state or a vulcanized state in a mold having male and female molds and the male mold 1a is held to 65-130 deg.C while the female mold 1b is held to 0-45 deg.C and the mold l is opened after 3-15min to selectively bond a rubber molded 2 article to the female mold 1b.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a rubber molded product. More specifically, the present invention is a rubber capable of selectively adhering a molded rubber molded product to a female mold of a molding mold, improving workability of taking out the rubber molded product from the mold, and enhancing productivity. The present invention relates to a method for manufacturing a molded product.

[0002]

2. Description of the Related Art In the case of molding a rubber composition with a molding die having a male mold and a female mold, rubber molding is considered in consideration of easiness and work efficiency of taking out the molded rubber product from the mold. It is desirable that the object always adheres to either the male type or the female type. Further, since the rubber molded product is attached to only one side in this way, the work of taking out the rubber molded product from the mold can be mechanized, and the productivity of the rubber molded product can be improved.

However, when the molding cycle is repeated tens of thousands of times, a part of the rubber molded product adheres to the male mold even though it is desired to adhere the rubber molded product only to the female mold, for example. , Lowers the workability and productivity of taking out the rubber molded product from the mold.

Therefore, although measures are taken such as coating the male mold with a fluorine-based resin or coating the male mold with a fluorine-based release agent, the fluorine-based resin is liable to cause partial peeling. However, there is a problem that the life is short and coating is time-consuming and costly, and the fluorine-based releasing agent remains attached to the rubber molded product, so that there is a problem that a post-treatment is required.

[0005]

As described above, in the conventional method for manufacturing a rubber molded product, the molded rubber molded product is attached only to one of the male mold and the female mold (for example, the female mold). However, there is a problem in that a part of the rubber molded product adheres to the other (for example, a male mold) to lower the workability of taking out the rubber molded product from the mold and the productivity.

Therefore, the present invention solves the above problems in the production of a conventional rubber molded product, and selectively adheres the molded rubber molded product only to the female mold to obtain a rubber molded product having a metal mold. The purpose is to improve the workability of taking out from the mold and improve the productivity of the rubber molded product.

[0007]

According to the present invention, after molding a rubber composition with a molding die having a male mold and a female mold, the male mold is
Keep at 5 to 130 ℃, and keep the female mold at 0 to 45 ℃, 3
After about 15 minutes, the mold is opened so that the rubber molded product selectively adheres only to the female mold, thereby achieving the above object.

That is, if the above-mentioned temperature difference is provided between the male mold and the female mold after molding the rubber composition as described above, the rubber molded product is selected only for the female mold having a low temperature. Will be adhered to.

In the present invention, the molded rubber product is selectively adhered only to the female mold having a low temperature.
It is considered that this is because the female mold and the rubber composition have different thermal conductivities, the female mold has a lower temperature and contracts faster, and the rubber molded product has a higher temperature and tends to expand.

The present invention will now be described with reference to the drawings. According to the present invention, when the mold is opened after molding.
As shown in FIG. 2, the rubber molding 2 selectively adheres only to the female mold 1b.

To explain this in detail, first,
Explaining from the drawings, FIG. 1 is a sectional view schematically showing a state of a rubber composition at the time of molding, and FIG. 2 is a sectional view schematically showing a state when a mold is opened by carrying out the present invention. Is.

In the figure, 1 is a mold and 2 is a rubber molding. The mold 1 is composed of a male mold 1a and a female mold 1b.
As shown in FIG. 2, the rubber molded product 2 is in contact with both the male mold 1a and the female mold 1b during molding, and when the mold 1 is opened, the rubber molded product 2 is either the male mold 1a or the female mold 1b. There is a possibility that it will also adhere to. However, in the present invention, after molding, the male mold 1a is kept at 65 to 130 ° C. and the female mold 1b is kept at 0 to 45 ° C.
Since the mold 1 is opened after 3 to 15 minutes while keeping the temperature at 0 ° C., the rubber molding 2 selectively adheres only to the female mold 1b as shown in FIG. As a result, the workability of taking out the rubber molded product 2 from the mold 1 is improved (that is, workability is improved because the rubber molded product 2 can be taken out at a fixed position), and the work of taking out the rubber molded product can be mechanized. Productivity can be increased.

On the other hand, FIG. 3 is a sectional view schematically showing a state in which the male die 1a and the female die 1b are continuously heated to the same temperature during molding and the die 1 is opened according to the conventional method. As shown in FIG. 3, the rubber molding 2 is attached not only to the female mold 1b but also to the male mold 1a. Therefore, when the rubber molded product 2 is taken out from the mold 1, it cannot be taken out at a fixed position, so that the workability is poor and, of course, mechanization of the taking out work is also impossible.

In the present invention, after molding, the male mold 1a is set to 65-1.
The temperature is kept at 30 ° C. This is for the purpose of selectively attaching the rubber molded product 2 only to the female mold 1 b by providing a temperature difference with the female mold 1 b when the temperature of the male mold 1 a is lower than 65 ° C. Can not be achieved sufficiently, and the temperature of the male mold 1a is 1
When the temperature is higher than 30 ° C., vulcanization is unfavorable for those which are molded in an unvulcanized state or semi-vulcanized state, and overvulcanization is unfavorable for those which are molded in a vulcanized state.

Further, the female die 1b is kept at 0 to 45 ° C. This is because when the temperature of the female die 1b becomes lower than 0 ° C., dew condensation or the like occurs and the female die 1b easily rusts (rusts). This is because if the temperature is higher than 45 ° C., it becomes difficult to selectively attach the rubber molded product 2 only to the female mold 1b.

In the present invention, the male die 1a and the female die 1b are
After setting the temperature of each as above, 3-1
After 5 minutes, the mold 1 is opened, but when the time until the mold 1 is opened is shorter than 3 minutes, heat transfer is insufficient and the rubber molded product 2 is selectively attached only to the female mold 1b. If it becomes difficult to open the mold 1 and the time until the mold 1 is opened becomes longer than 15 minutes, the temperature difference between the rubber molded product 2 and the female mold 1b becomes small, and the rubber molded product 2 is only transferred to the female mold 1b. This is because it becomes difficult to adhere selectively.

According to the present invention, the male mold 1 is formed after molding the rubber composition.
Since a and a female mold 1b are kept at the above temperatures and a temperature difference is provided between them, the temperature at the time of molding is not regulated. Therefore, the molding is carried out with the rubber composition in an unvulcanized state. It can be applied to both semi-vulcanized and vulcanized products.

Specific examples of molding in the unvulcanized state include, for example, molding of a half shell of a soft baseball, and specific examples of molding in a semi-vulcanized state include, for example, three layers. Examples include molding of the second and third half shells of a solid golf ball having a structure and the half shell for the outer layer of a two-piece solid golf ball.
Specific examples of molding in the vulcanized state include molding of a half shell for the inner core of a tennis ball. Of course, the present invention is not limited to these examples, but can be applied to the molding of other types.

In the present invention, the mold for molding the rubber composition is expressed as a mold, but the material of the mold does not necessarily have to be metal, and the molding mold is a single male mold. Not only is it made up of a mold and one female mold, but for example, a male mold is a type with protrusions on both sides called a core, and a female mold is arranged on both sides of it. It may be configured by a male type and two female types. The male type and female type may be further divided. Further, heating the rubber composition to impart elasticity to the rubber composition is referred to as vulcanization, but the vulcanization does not necessarily have to be due to sulfur (sulfur).

[0020]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only those examples.

Examples 1 and 2 and Comparative Examples 1 to 3 With respect to 100 parts by weight of cis-1,4-polybutadiene,
40 parts by weight of zinc acrylate, 4.5 parts by weight of zinc oxide and 1.0 part by weight of dicumyl peroxide were mixed and kneaded to prepare a rubber composition, and the rubber composition was a solid golf ball having a three-layer structure. Second layer (hereinafter referred to as "outer core")
After molding into a mold for half shell molding, which is made up of a male mold and a female mold and heated under pressure at 150 ° C. for 20 minutes under a semi-vulcanized state, the male mold and the female mold are respectively shown in Table 1. The temperature was set to that shown in Table 2 and the mold was opened after 10 minutes, and the state of adhesion of the rubber molded product to the male mold and the female mold was examined. The results are shown in Tables 1 and 2. Table 1 shows the temperature conditions and test results of the male and female molds of Examples 1 and 2, and Table 2 shows those of Comparative Examples 1 to 3.

In the test, 5 presses for molding were used.
This was repeated up to 00 times to form 50 half shells for the outer core by pressing once each. The numerical values showing the results in Table 1 and Table 2 indicate the number of the 50 outer shell half shells that were formed and attached to the male mold, which is, so to speak, the degree of failure.

[0023]

[Table 1]

[0024]

[Table 2]

As is clear from the results shown in Table 1, in Examples 1 and 2 of the present invention, there was no outer shell half shell attached to the male mold, and all 50 outer shell half shells were female. It was attached to the mold. This did not change after 500 press cycles.

On the other hand, as shown in Table 2, in Comparative Examples 1 and 2 in which the male and female temperatures were the same, a considerable number of outer shell half shells were used regardless of the temperature. Attached to the mold. Also in Comparative Example 3 in which the temperature of the female mold was higher than that of the male mold, the outer shell half shells were separated and attached to the male mold and the female mold.

[0027]

As described above, according to the present invention,
The rubber molding can be selectively attached only to the female mold.

Therefore, the workability of taking out the rubber molded product from the mold is improved, and since the work of taking out the rubber molded product can be mechanized, the productivity of the rubber molded product can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a state at the time of molding a rubber composition with a mold.

FIG. 2 is a cross-sectional view schematically showing a state when the present invention is carried out and a mold is opened.

FIG. 3 is a cross-sectional view that schematically shows the state when the mold is opened according to the conventional method.

[Explanation of symbols]

 1 mold 1a male 1b female 2 rubber molded product

Claims (1)

[Claims] 1. A rubber composition is molded in an unvulcanized state, a semi-vulcanized state or a vulcanized state using a molding die having a male die and a female die, and then the male die is kept at 65 to 130 ° C., and Female type 0-4
A method for producing a rubber molded product, which comprises maintaining the temperature at 5 ° C. and opening the mold after 3 to 15 minutes to adhere the rubber molded product to the female mold.