JPS59182724A - Mold formation of rubber product having solid-sponge two-layer structure - Google Patents

Abstract

PURPOSE:To easily obtain a rubber product having a solid-sponge two-layer structure by a method in which a partly unvulcanized rubber product is obtained by using molds with heat-insulating plates partly, and the unvulcanized portion is made into a spongy state and vulcanized. CONSTITUTION:A mold 2, for example, is made up of a top force 21 and a bottom force 22 which are formed of a heat-insulating plate, e.g., asbestos laminate plate, etc, and a square-cylindrical intermediate force 23 made of a metal. An unvulcanized rubber 1 is packed into the mold 2 and heated from the intermediate force 23 for the primary vulcanization to obtain a molding having a vulcanized portion 1a and an unvulcanized portion 1b. The molding is taken out of the mold 2, whereupon volatile components such as moisture and compounding agents present in the unvulcanized portion 1b are vaporized to make it a spongy state. The molding is put in the metal mold 3 and heated from its all metal surrounding for the secondary vulcanization to obtain a rubber product having a two-layer structure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the molding of a two-layer rubber product consisting of a solid part and a sponge part.

1- Integral molding of a two-layer rubber product has already been carried out by extrusion molding. )
There is a method of joining these together.

Accordingly, one object of the present invention is to provide a method for molding a solid sponge two-layer structure product.

That is, in the present invention, first, an unvulcanized rubber material is filled into a mold partially constituted by a heat insulating plate, and heated and pressurized to keep a portion of the rubber material close to the heat insulating plate unvulcanized, while leaving the other portions unvulcanized. The first vulcanization is carried out to vulcanize the rubber material.Next, the mold is opened and volatile components such as moisture and compounding agents in the unvulcanized rubber material are vaporized and the area is covered with a sponge-like coating. .Furthermore, the obtained molded body is heated as a whole with gold or hot air, and the sponge part is heated with Ito.
I&+16 second vulcanization is performed.

The present invention will be explained below with reference to illustrated embodiments.

Figures 1 to 5 show culms being manufactured according to the present invention.

First, as shown in FIG. 1, a mold 2 is filled with an unfilled rubber material 1.The mold consists of an upper mold 21 made of a heat insulating plate such as an assemblage plate, a lower mold 21, type 22 and rectangle ir',)
A fully bent medium mold 23 with a shape of J: is constructed. In addition, l'l
'J 21 A3 J, hi; ``122 rubber A diagonal 1 contacting surface IJ-\5 ya) is convex.Therefore, heat the medium sized 23 = rmu monthly interest 1. Perform the first vulcanization using the rubber.
The outer periphery of 'i+1 near the middle size 23 is vulcanized,
Upper mold 21 J: The part J3 in contact with the upper mold 22 and the center part are constrained to be unvulcanized or have only one eave. In Figure 2 a
3, 1d indicates a vulcanized portion, and 1b indicates an unvulcanized portion.

Next, when the mold is removed and the molded body is taken out, as shown in Figure 3, volatile components such as moisture and compounding agents contained in the unvulcanized portion 1b (Figure 2) are removed. The sponge portion 1C is formed by foaming. In this embodiment, as shown in FIG. 1, the contact surfaces of the upper mold 21d5 and the lower mold 23 with the rubber material 1 are convex, and the surface of the mold is concave.
Normally, during the foaming process, the two layers of the sponge portion 1C would swell a little, or in this case, it would swell only a little as shown in Figure 3.
Some people are in a state of swelling.

Next, the above rubber molded body is shown in FIG. 4. J: Sea urchin upper mold 31,
The filler 1 is placed in a mold 3 consisting of a lower mold 32, a middle mold 33, metals 32, 33, and 1, and the rubber molded body is heated from the entire circumference to perform secondary vulcanization. As a result, the unvulcanized sponge part I
C (Fig. 3) is vulcanized by Mf, and the vulcanized sponge part 1d becomes thin.The upper and lower parts of the vulcanized sponge part 1d are sweated by the lower molds 31 and 32, and the -C air bubbles are crushed, making it thin. A solid part is formed. .

In this way, as shown in Fig. 5, the diameter of the upper part of the sea urchin is concave along the axis of the vulcanized sponge part 1d, and the rubber consists of solid parts 1 to 1a on the outer periphery of the vulcanized sponge part 1d. The product △ is obtained.

Figure 6 shows the static spring characteristics (line a) when a cart in the direction of the arrow shown in Figure 5 is added to the above rubber product obtained by the present invention.
Figure 1 shows the static spring characteristics (line b) of a comparative paper made entirely of solid rubber.

In the product according to the present invention, the amount of deformation is large because the sponge portion is crushed in an area where the front vehicle is small, and once a certain deformation (2) is reached, it becomes difficult to deform further (21).

Rubber products with such characteristics are suitable for use in anti-vibration rubber, for example in engines and accommodations. On the other hand, the spring constant is high, so the damping effect is reduced.

The location, shape, and size of the sponge part in the rubber product are selected depending on the location of the heat insulating member in the mold, the heating temperature and time of the mold.

As explained above, according to the present invention, it is possible to form a solid rubber material extremely easily using one type of rubber material without having to use two types of rubber and sponge rubber to join them.
By integrally molding a rubber product with a two-layer sponge structure, and by combining both layers! Bad behavior can be selected in a timely manner.

4.Drawings (1) t>'J 'Ii 'J u2 Figures 1 to 5 show the manufacturing process for the rubber products of the present invention, and Figure 6 shows the products obtained by the present invention. It is a diagram that does not show the static spring characteristics of a product made only of solid rubber.

1... Mikasaki Rubber monthly fee 'Ia...Solid part 1C...Unvulcanized sponge part 1d... Vulcanized sponge part 2...Mold for primary vulcanization 21.22・・・・・・i Hot plate 3...Mold for secondary vulcanization Figure 1 Figure 2 Figure 5 Figure 6

Claims (1)

[Claims] The part of the mold that comes into contact with the rubber material is made up of a heat insulating plate, and the inside of the mold is filled with unvulcanized rubber material and heated under pressure.
A first vulcanization step in which a portion of ΔJ+1 close to the heat insulating plate is kept unvulcanized and the other portions are vulcanized; The volatile components contained in the part are evaporated. Secondary addition (Ibi ni culm and J: Mold forming method for rubber products with two-layer structure of solid sponge)