JPS642485B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a porous rubber sheet (screen) used for sieving crushed stone and ore, and in particular, during its manufacture, This invention relates to a method for producing a porous rubber sheet (screen) that leaves almost no burrs and requires almost no post-treatment such as buffing.

(Prior art) As a conventional technology, a raw raw rubber sheet is pressed between a die provided with a large number of hole-forming protrusions and a flat surface of a molding press pressure plate to produce a porous rubber sheet (porous rubber screen). By interposing a release sheet such as a cloth sheet or a vulcanized rubber sheet between the material raw rubber sheet and the pressure plate, and peeling off the cloth sheet or vulcanized rubber sheet after vulcanization, There is a method of obtaining a porous rubber screen without burrs (for example, the inventions described in Japanese Patent Publication No. 49-34474 and Japanese Patent Publication No. 52-10478).

(Problems to be Solved by the Invention) However, the above-mentioned prior art has the following problems. In other words, release sheets such as cloth sheets and vulcanized rubber sheets have too much elasticity, so wrinkles and unevenness easily occur on the surface of the final product screen, resulting in uneven thickness, which makes it difficult to use the product in actual use. Point contact occurs at the part that contacts the screen support frame, and this causes phenomena such as abnormal wear and cutting. In addition, if the thickness of the burr generated between the release sheet and the top surface of the hole-forming protrusion is thin (0.1 to 0.2 mm), the binding force between the release sheet and the burr exceeds the strength of the burr itself, so the peeling The burr is relatively easy to remove when peeling the sheet, but if the burr becomes partially thick due to the weight and shape of the product, it becomes difficult to remove the burr, and the burr may remain on the edge of the hole of the screen product. Many of them are troublesome to remove. These burrs are usually removed by buffing, but since rubber is an elastic material, depending on the direction of polishing, there will be parts where the burrs are removed and parts where they are not. In other words, the burr on the side where the burr becomes the main body is cut, but the burr cannot be cut in the direction from the main body to the burr.
Furthermore, if a rubber material that is easily buffed is used, the durability of the screen itself will be reduced. Furthermore, according to the method of punching out burrs using a punch, if the tip of the punch does not hit the burr surface at right angles and accurately, a small amount of burr will remain in the shape of a flange at the edge of the hole, and if there are many holes, the punch It is difficult to set the punch accurately in the hole, and if the punch itself is made smaller, it still has the disadvantage of leaving a flange-shaped burr on the edge of the hole. Removing these burrs was a very laborious and time-consuming task.

(Means for solving the above-mentioned problems) The present invention was invented in view of the above-mentioned problems, and it is possible to produce this kind of porous rubber screen without leaving almost any burrs attached to the product. The present invention aims to provide a method for manufacturing a porous rubber screen that hardly requires any buff removal means such as subsequent buffing.

The configuration of the present invention will be explained below.

That is, the gist of the present invention is as follows:
In a method of manufacturing a porous rubber sheet by sandwiching a raw raw rubber sheet between a frame provided with a large number of hole-forming projections and a flat surface of a pressurizing/heating plate, there is a gap between the raw raw rubber sheet and the pressurizing/heating plate. , production of a porous rubber sheet characterized by interposing a release sheet and cardboard, press-molding a raw rubber sheet, unloading the pressure heating plate, and peeling off the release sheet and cardboard. It's a method.

Next, one embodiment of the present invention will be described based on the accompanying drawings.

Figure 1 is a cross-sectional view of a porous rubber sheet immediately before production, where 1 is a press heating plate, and 2 is a press heating plate 1.
3 is a hole-forming projection provided on the frame 2, and 5 is a top 9 of the hole-forming projection 3,
This shows a pressurizing and heating plate that is movable up and down so as to approach or separate a flat surface parallel to the plate. and,
In these devices, the raw rubber sheet 4 is placed on the top 9 of the hole-forming projection 3 of the frame 2, and then,
A release sheet 6 and cardboard 7 are placed on top of this.
Note that 12 is a lower mold for fixing the hole-forming projection of the frame.

Then, as shown in FIG. 2, by lowering the pressure heating plate 5, the
A raw rubber sheet 4 is clamped and pressed between the frame body 2.
In this way, the raw rubber squeezed between the pressurizing and heating plate 5 and the frame 2 fills the void 8 existing between the hole-forming protrusions 3 of the frame 2.
burrs 10 are formed between the top 9 of the frame 2 and the release sheet 6, but the layer becomes thinner due to the pressing force of the cardboard, which has both appropriate rigidity and appropriate elasticity. Note that the cardboard does not have to be one piece;
It will be more effective to use two or more plates in consideration of various conditions such as the degree of pressure of the pressure plate, vulcanization conditions, and the thickness of the product to be manufactured. Next, as shown in FIG. 3, after unloading the pressure heating plate 5, the release sheet 6 and the cardboard 7 are peeled off as shown in the figure, thereby causing the burr 10 to adhere to the back surface of the release sheet 6. urge

In addition, if the release sheet has a slightly uneven surface 11 on the back side as shown in Fig. 4, the burrs will dig into the uneven surface well, increasing the bonding force with the release sheet and exceeding the strength of the burr itself. Becomes more powerful and especially optimal. The material for the release sheet is appropriately selected from materials with good release properties, such as polyester, Tetron, Teflon, and release paper.

(Example) In the method for manufacturing the porous rubber sheet of the present invention described above, cardboard with a thickness of 1 mm is used as the cardboard, a polyester sheet (0.1 mm) whose one side is sandblasted is used as the release sheet, and raw rubber is used as the material. Rubber with particularly good abrasion resistance was used as the material.

The surface pressure of the pressure heating plate is 30Kg/ ^cm2 , the hole size is 25mm square,
A porous rubber screen with a width of 1500 mm and a length of 600 mm was manufactured.

There were no burrs in the pores of the obtained porous rubber screen, and all burrs were attached to the back surface of the release sheet that had been peeled off.

(Effects) In the method for manufacturing the porous rubber screen of the present invention constructed as described above, cardboard and a release sheet are interposed between the pressure heating plate and the material raw rubber sheet, and in particular, since the cardboard is interposed, Due to the appropriate rigidity of the cardboard and the pressing force due to the appropriate elasticity, the area around the burr that occurs between the pressure heating plate and the top of the hole-forming protrusion of the frame becomes a thinner layer, and the release sheet and cardboard are separated. The binding force between the release sheet and the burr is much greater than the strength of the burr itself, and when the release sheet is removed, the burr can be completely attached to the back side of the release sheet and removed. It is possible.

In addition, thick paper such as cardboard has extremely low heat shrinkage and good dimensional stability compared to rubber etc., so it is not affected by the heat during pressure vulcanization and does not wrinkle. The surface of the porous rubber screen will not be uneven. In particular, due to fluctuations in the pressing force of the pressure heating plate and other manufacturing conditions, even if one sheet of cardboard is not sufficient to prevent wrinkles, two or three sheets of cardboard may be used.
By using a plurality of sheets, the occurrence of wrinkles can be completely prevented, which is more effective.

Furthermore, since the back side of the release sheet has minute irregularities formed, when the release sheet and cardboard are peeled off, the binding force between the burr and the release sheet is greater than the strength of the burr itself, making it easy to remove. The burr can be removed.

Furthermore, since almost no burrs remain in the pores of the resulting porous rubber screen, there is no need to remove burrs by buffing or punching, and there are no burrs left in the pores of the frame, improving work efficiency. Extremely good. In addition, the resulting product porous rubber screen has no burrs in the holes, improving sieving efficiency, and the product surface is flat without any unevenness or wrinkles, so it does not make point contact with the screen support frame. Since there is surface contact, troubles such as abnormal wear and cutting are avoided, and durability in use is improved.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram when the present invention is implemented (immediately before manufacturing a porous rubber sheet), Fig. 2 is an explanatory diagram when the present invention is also implemented and the pressure heating plate is pressurized, and Fig. 3 is an explanatory diagram when the present invention is applied. FIG. 4 is a partially enlarged sectional view of the release sheet used in the present invention. DESCRIPTION OF SYMBOLS 1... Press heating plate, 2... Frame body, 3... Hole forming protrusion, 4... Material raw rubber sheet, 5... Pressure heating plate, 6... Release sheet, 7... Cardboard, 8... void, 9... top, 10... burr, 11... uneven surface, 12... lower mold.

Claims (1)

[Claims] 1. In a method of producing a porous rubber sheet by sandwiching a raw rubber sheet between a frame provided with a large number of hole-forming projections and a flat surface of a pressurizing and heating plate, the gap between the raw raw rubber sheet and the pressurizing and heating plate is After interposing a release sheet and cardboard and press-molding the material raw rubber sheet,
A method for producing a porous rubber sheet, which comprises unloading a pressure heating plate and peeling off a release sheet and cardboard.