JPS6132723A - Preparation of perforated rubber sheet having no burr - Google Patents

Abstract

PURPOSE:To obtain the titled sheet in good workability, by holding a base rubber sheet between a frame body provided wth perforation forming projections and a heated press platen through a release layer and a specific spacer under pressure to apply press molding thereto before releasing pressure and peeling off the release layer. CONSTITUTION:A base green rubber sheet 4 is placed on the top part 9 of a large number of perforation forming projections provided to a frame body 2 and a release sheet 6 and cardboard 7 are placed on said rubber sheet 4 as a release layer in a superposed state. Further, a spacer 10 provided with perforation at the positions corresponding to the top parts 9 of the aforementioned perforation forming projections by drilling is placed on said release layer and a heated press platen 5 is fallen onto said spacer to hold the green rubber sheet 4 under pressure. After the aforementioned rubber sheet 4 generates protruded lump breaking through the release layer, pressure is released and the release layer is peeled off to obtain the objective rubber sheet.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a porous rubber sheet (screen) used for sieving crushed stone or ore, and removing paris generated during the process from the surface of the product. The present invention also relates to a method for producing a porous rubber sheet (screen) that does not require any adhesion and hardly requires post-processing such as puffing.

(Prior art) As a conventional technology, a porous rubber sheet (porous rubber screen) is manufactured by pressing a raw raw rubber sheet between a gou provided with a large number of hole-forming protrusions and a flat surface of a molding press pressure plate. 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 is completed. There is a method to obtain a porous rubber screen without paris (for example,
(Inventions described in Japanese Patent Publication No. 9-34474 and Japanese Patent Publication No. 52-10478).

(Problem to be solved by this invention) However,
The above-mentioned conventional technology 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, and the thickness is uneven, making it difficult to use the screen when actually using the product. Point contact occurs at the part where it contacts the support frame, and phenomena such as abnormal wear and cutting occur due to this. In addition, if the thickness of the barrier generated between the release sheet and the top surface of the hole-forming protrusion is thin (0.1~
For 0.2mfi), the binding force between the release sheet and the Paris is -L greater than the strength of the Paris itself, so the Paris is relatively easy to peel off when the release sheet is peeled off, but depending on the weight and shape of the material, the firmness may be partially When the film becomes thicker, it becomes difficult to remove the paris, and the paris often remains on the edges of the holes in the screen product, making it troublesome to remove. These pars are usually removed by puffing, but since rubber is an elastic body, there are parts where the paris can be cut and parts where they cannot be cut, that is, the paris on the side that becomes the main body from the paris. This means that the edge will not cut in the direction from the main body to the edge. Furthermore, if a rubber material that is easily puffed is used, the durability of the screen itself will be reduced. Then use a punch to punch out the hole (according to the method, if the tip of the punch does not hit the hole surface at right angles and accurately, a small amount of hole will remain in the shape of a flange at the edge of the hole, and if there are many holes) It is difficult to set the punch accurately in the hole, and if the punch itself is made smaller, it also has the disadvantage of leaving a flange-like burr on the edge of the hole.Removing these burrs is extremely time-consuming. It was a time-consuming task.

(Means for solving the above-mentioned problems) The present invention was invented in view of the above-mentioned problems. The purpose of the present invention is to provide a method for producing a porous rubber screen that does not require any subsequent puffing or other means for removing paris.

The configuration of the present invention will be explained below.

That is, the gist of the present invention is to provide a method for manufacturing a porous rubber sheet by pressing a raw rubber sheet between a frame provided with a large number of hole-forming protrusions and a flat surface of a pressure heating plate. A release layer is interposed between the material raw rubber sheet and the pressure heating plate, and holes are provided between the release layer and the pressure heating plate at positions corresponding to the protrusion positions of the frame body. This method of manufacturing a porous rubber sheet is characterized in that a spacer is interposed to form a raised lump that breaks through the mold release layer during pressure molding of the rubber sheet, and then the pressure is removed and the mold release layer is peeled off.

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

Figure 1 is a cross-sectional view of the porous rubber sheet just before manufacturing.
1 is a press hot plate, 2 is a frame placed on the press hot plate 1,
Numeral 3 denotes a large number of hole-forming projections provided on the frame 2, and 5 is arranged movably up and down so as to approach or separate a flat surface parallel to the top 9 of the hole-forming projection 3. A pressurized heating plate is shown.

In these devices, the hole forming protrusion 3 of the frame body 2
A raw rubber sheet 4 is placed on the top 9 of the sheet, and then a release sheet 6 and a cardboard 7 are placed on top of each other as a release layer.

Further, a spacer 10 having a hole formed at a position corresponding to the top of the hole-forming projection 3 is interposed between the mold release layer and the pressurizing platen. In addition, 15 is a lower mold for fixing the hole-forming protrusion of the frame.

Then, as shown in FIG. 2, by lowering the pressure heating plate 5, the raw rubber sheet 4 is attached to the frame 2 via the spacer 10 and the release sheet 6 and cardboard 7, which are release layers. Pressure is applied in between and vulcanization molding is performed.

Thus, pressurized heat! The raw rubber squeezed between Ii 5 and the frame 2 bites into the gap 8 existing between the hole-forming protrusions 3 of the frame 2 and fills the gap 8 between the top 9 of the frame 2 and the release sheet 6. 11 is formed, but by increasing the pressure,
The pressure of the particles exceeds the strength of the release sheet and the cardboard, and eventually breaks through them, and the particles form a raised mass 14 within the hole 13 of the spacer 10, as shown in Figure 3 of the coffin. This results in
The thickness of the barrier formed between the top of the hole-forming protrusion and the release sheet becomes thinner.

Note that the thickness of paper thins due to the pressing force due to the appropriate rigidity and elasticity of the cardboard, but the cardboard does not necessarily have to be a single sheet, and depends on the degree of pressure on the pressure plate, the vulcanization conditions, Considering various conditions such as the thickness of the product to be manufactured, using two or more sheets will be more effective.

Next, as shown in FIG. 4, after unloading the pressure heating plate 5,
By peeling off the release sheet 6 and the cardboard 7 as the release layer as shown in the figure, the Paris 11 is attached to the back side of the release sheet 6 and is completely removed from the surface of the porous rubber sheet that is the product. removed.

If the release sheet is textured on the back side with a minute uneven surface 12 as shown in Fig. 5, the particles will bite into the uneven surface well, increasing the bonding force with the release sheet and causing the particles to form on their own. This is preferable because it is greater than the strength. As the material for the release sheet, a material with good release properties such as polyester, Tetoron, Teflon, or release paper may be selected as appropriate, and as the cardboard, one that is usually commercially available as cardboard may be used.

In this way, the desired porous rubber screen is manufactured.

(Example) In the method for manufacturing the porous rubber sheet of the present invention described above, 1fi thick cardboard was used as the cardboard, a polyester sheet (0.1 m) with one side sandblasted as the release sheet, and the material As the raw rubber, rubber having particularly good abrasion resistance was used. The spacer used was a steel plate (same as a normal mold), about 10 mm thick, with a 5 tm f hole located at a position corresponding to the hole forming protrusion. The surface pressure of the pressure heating plate is 30~
35 kg / cJ or more, hole size 25 m square, 15
A porous rubber screen with a width of 0.00 mm and a length of 600 mm was manufactured.

The pores of the obtained porous rubber screen had no particles at all.
All of the particles were attached to the back side of the release sheet that had been peeled off.

(Function and Effect) The method for manufacturing the porous rubber screen of the present invention configured as described above involves interposing cardboard and a release sheet between the pressure heating plate and the raw rubber sheet, and using a spacer with holes. Moreover, since the holes of the spacer are inserted so as to correspond to the positions of the hole-forming protrusions of the frame, by applying pressure above a certain level when molding the porous rubber sheet, excess rubber material is removed as a mold release layer. The material breaks through and collects in the hole of the spare plate as a raised lump, and the raised lump plays the role of a hook to integrate the release layer and the Paris, so that the release layer is not left behind on the frame when the release layer is peeled off. , the mold release layer can be reliably adhered and deburring work can be performed.

Furthermore, by interposing the cardboard, the pressure generated by the appropriate rigidity and elasticity of the cardboard makes it possible to reduce the thickness of particles generated between the release sheet and the tops of the hole-forming protrusions on the frame using a thinner layer. becomes. As a result, when peeling off the release sheet and cardboard, the adhesive force between the release sheet and the paper is much greater than the strength of the paper itself, making the process of removing paper more reliable and easy. be able to.

In addition, thick paper such as cardboard has extremely low heat shrinkage and good dimensional stability compared to rubber etc., and is not affected by heat during pressure vulcanization, so there is no wrinkles etc. This does not cause unevenness to be reflected on the surface of the porous rubber screen that becomes the product. Also, 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 release sheet and the release sheet is greater than the strength of the release sheet itself. It makes the work easier.

Furthermore, since almost no debris remains in the pores of the resulting porous rubber screen, there is no need to remove debris using puffs or punches, and no debris remains in the holes of the frame, making work easier. is extremely good. In addition, the resulting product porous rubber screen has no particles in the pores, improving sieving efficiency, and the product surface is flat without unevenness or wrinkles, so it does not make point contact with the screen support frame. Since there is surface contact, there are no problems such as abnormal wear or cutting, and the durability of use can be improved.

[Brief explanation of the drawing]

Figure 1 is when the present invention is being carried out (immediately before manufacturing a porous rubber sheet)
FIG. 2 is an explanatory diagram of the present invention when the pressure heating plate is pressurized, FIG. 3 is an enlarged explanatory diagram of the main part of FIG. 2, and FIG. FIG. 5, which is an explanatory view when the pressure and heat plate is unloaded after molding, is a partially enlarged sectional view of the release sheet used in the present invention. ■...Press v3! Board, 2... Frame body, 3... Hole forming protrusion, 4... Raw rubber sheet as material, 5... Pressure heating plate, 6... Release sheet, 7... Cardboard, 8...・Void,
9...Top, 10...Spacer, 11...Paris,
12... Uneven surface, 13... Hole, 14... Raised mass, 15... Lower mold.

Claims (1)

[Claims] In a method of manufacturing a porous rubber sheet by pressing a raw 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, there is a gap between the raw raw rubber sheet and the pressurizing and heating plate. , a mold release layer is interposed, a spacer having a hole provided at a position corresponding to the protrusion position of the frame is interposed between the mold release layer and the pressure heating plate, and the rubber sheet is pressure molded. A method for producing a porous rubber sheet, which is characterized in that after generating a raised mass that sometimes breaks through a mold release layer, the pressure is removed and the mold release layer is peeled off.