JP2608560B2 - Method for producing porous rubber roll - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for producing a porous rubber roll, and more particularly to foaming and vulcanization of an unvulcanized rubber material containing a foaming agent, and compression and sintering of a thermoplastic powder. The present invention relates to a porous rubber roll obtained by the above method.

[Prior Art] Conventionally, a porous roll has been manufactured as shown in FIGS. Here, FIG. 5 is a sectional view taken along line XX of FIG.

First, a lower mold 2 in which the metal core 1 is set in the vertical direction is prepared. Subsequently, after the cylindrical body 3 is fitted to the peripheral end of the upper surface of the lower mold 2, thermoplastic powder is applied to the lower mold 2 in a region surrounded by the cylindrical body 3, the cored bar 1, and the lower mold 2. While filling. Next, an upper mold (lid) 4 is fitted from above the cylindrical body 3. Furthermore,
After performing a heat treatment to sinter the thermoplastic powder to form a sintered body 5, the cored metal 1, the sintered body 5 and the lid 4 are integrated to produce a drawn porous rubber roll.

[Problems to be Solved by the Invention] However, according to the prior art, when filling a region surrounded by the cylindrical body 3, the core bar 1, and the lower mold 2 with the thermoplastic powder, the lower mold 2 is vibrated. Since the powder is filled, it is difficult to uniformly fill the powder in the vertical direction due to the nature of the powder (for example, a powdery powder or a sticky powder). Therefore, the density difference between the upper and lower portions of the sintered body 5 becomes large, and a roll having a uniform density cannot be formed. Conventionally, the density of the sintered body is changed by changing the particle size of the thermoplastic powder and changing the filling amount of the powder, so there is a limit.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for producing a porous rubber roll having a sintered body having a uniform density and capable of freely changing the density of the sintered body. .

[Means for Solving the Problems] The present invention relates to a step of forming a tubular unvulcanized rubber material containing a foaming agent around a cored bar, and forming the tubular unvulcanized rubber material into a lower mold. And setting between a cylindrical unvulcanized rubber material and the cylindrical body, selected from a mixture of thermoplastic powder and either inorganic powder or organic powder and thermoplastic powder. Filling an upper mold into the cylindrical body, pressurizing and heating the cylindrical unvulcanized rubber material to foam and vulcanize the same, and the thermoplastic powder and the inorganic powder. Compressing and sintering one selected from a mixture of either a powder or an organic powder and a thermoplastic powder.

The cylindrical member according to the present invention only needs to have a cylindrical inside, and includes an integrated mold or a mold that can be divided into a plurality of molds.

According to the present invention, during the heat treatment, the unvulcanized rubber material containing the foaming agent foams to cause vulcanization, and the foaming pressure is uniformly transmitted in the cylinder direction (outer peripheral direction), The plastic powder is sintered to form a sintered body. As a result, it is possible to obtain a porous rubber roll having less variation in the density of the sintered body than in the related art. Further, for example, when increasing the density of the sintered body, it is only necessary to increase the foaming pressure by forming an unvulcanized rubber material in a thick core, and it is easy to adjust the hardness of the sintered body.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. However, the same members as those in the related art are denoted by the same reference numerals, and description thereof is omitted.

(1) First, unvulcanized rubber tube as described below
11 and thermoplastic powder are prepared.

Unvulcanized rubber tube NBR raw rubber 100 parts by weight Zinc flower No.1 5 parts by weight Sulfur 2 parts by weight Accelerator (trade name Axel DM, Kawaguchi Chemical Co., Ltd.) 1 part by weight Anti-aging agent (trade name Nocrack 224, Ouchi Shinko Chemical (product) 1
Parts by weight Stearic acid 1 part by weight Filler (trade name Carplex # 80, Shionogi Pharmaceutical Co., Ltd.) 20 parts by weight Plasticizer (trade name DOP, Mitsubishi Monsanto (trade name)) 10 parts by weight Foaming agent (trade name Neoservon P1000M, Eiwa Chemical Co., Ltd.)
5 parts by weight The above-mentioned compounding ingredients are mixed and kneaded by a roll mill, then separated, and further extruded into an unvulcanized rubber tube 10 having a predetermined size (note that the raw material rubber is NR, SBR, other synthetic rubbers). May be).

Thermoplastic powder First, a rubber compounding agent (the same compound as the unvulcanized rubber tube but excluding the foaming agent) is mixed and kneaded by a roll mill, fractionated by a calender roll, wound around an iron core, and subjected to a normal roll forming process. A vulcanized rubber was produced, and this was further polished with a glider to produce a vulcanized rubber powder. Next, a compounding agent consisting of 100 parts by weight of the vulcanized rubber powder, 30 parts by weight of vinyl chloride and 10 parts by weight of DOP was mixed and stirred for about 30 minutes by a super mixer, and then DOP (plasticizer) was added and mixed for about 10 minutes. The mixture was stirred to obtain a thermoplastic powder in which a vulcanized rubber powder, vinyl chloride and a plasticizer were uniformly mixed.

(2) Next, the cored bar 1 was inserted into the unvulcanized rubber tube 11 so that the upper and lower ends were exposed, and the cored bar 1 was set in the lower mold 2 in the vertical direction. Subsequently, after the cylindrical body 3 is fitted to the peripheral end of the upper surface of the lower mold 2, the thermoplastic powder is filled in a region surrounded by the cylindrical body 3, the unvulcanized rubber tube 11, and the lower mold 2. . Next, from above the cylindrical body 3, an upper mold (lid)
4 is fitted. Further, a sintered body 12 is formed by sintering a thermoplastic powder while performing a heat treatment in a heating furnace (not shown) to foam the unvulcanized rubber tube 11, and after cooling, the core metal 1, the unvulcanized A rubber foam formed by vulcanizing and foaming the rubber tube 11, the sintered body 1 and the lid 4 were integrated to produce a drawn porous rubber roll.

Thus, according to the present invention, during the heat treatment, the unvulcanized rubber tube 11 containing the foaming agent foams to cause vulcanization, and the foaming pressure is uniformly transmitted in the cylinder direction (outer peripheral direction).
The thermoplastic powder is sintered to form a sintered body 12. As a result, it is possible to obtain a porous rubber roll in which the density of the sintered body 12 does not vary as compared with the related art. When the density of the sintered body 12 is to be increased, for example, it is only necessary to wind a thick unvulcanized rubber tube around the cored bar 1 to increase the foaming pressure, and the hardness of the sintered body 12 can be easily adjusted.

(Experimental example 1) Outer diameter of cored bar 8 mm Outer diameter of rubber tube with cored bar inserted 16.5 mm Inner diameter of tube 28 mm Heating furnace temperature 170 ° C Heating time 30 minutes A porous rubber roll was manufactured under the above conditions. However, the porosity of the sintered body 12 was 42%.

(Experimental Example 2) When the outer diameter of the rubber tube in which the metal core was inserted was set to 14 mm, and other conditions were the same as in Experimental Example 1, the foaming pressure was lower than in the experimental example, and the porosity of the sintered body was lower. 55%.

From the above, it is apparent that the porosity (density) of the sintered body 12 is changed by changing the thickness of the rubber tube.
In fact, the porous rubber roll (sponge roll) produced in this manner has uniform open cells without variation in the sintered body 12, has very small cells, and absorbs water and the like by capillary action. Therefore, when the film was used as a draining roll of a washing machine such as an automatic developing machine, water of the film could be uniformly and completely sucked. Also, since the unvulcanized rubber tube 11 is vulcanized and foamed to form a sponge, it has a good cushioning property, gives a soft touch to the film, and has a large nip width to improve water suction, thereby improving the production effect. The performance effect was also improved.

In the above embodiment, the case where the core metal is directly fitted into the unvulcanized rubber tube has been described, but the present invention is not limited to this. For example, the core metal may be fitted into an unvulcanized rubber tube with an insulating material such as a resin formed on the surface. Also,
The unvulcanized rubber material is not limited to the tube state, and may be wound around a core bar in a belt-like state to join the ends of the unvulcanized rubber material.

[Effects of the Invention] As described in detail above, according to the present invention, a sintered body having a uniform density and sufficient hardness as compared with the conventional one can be obtained, and the density of the sintered body can be freely changed, thereby automatically A method for producing a porous rubber roll useful as a draining roll after washing with a developing machine or the like can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a method for manufacturing a porous rubber roll according to one embodiment of the present invention, and FIG. 2 is a YY line in FIG.
FIG. 3 is a development view before the heat treatment of FIG. 1, FIG. 4 is a cross-sectional view for explaining a conventional method of manufacturing a porous rubber roll, and FIG. 5 is a cross-sectional view of FIG. It is sectional drawing which follows the X-ray. 1 ... core metal, 2 ... lower mold, 3 ... cylindrical body, 4 ... upper mold (lid), 11 ... unvulcanized rubber tube, 12 ... sintered body.

Continuation of front page (56) Reference JP-A-57-179415 (JP, A) JP-A-58-118325 (JP, A) JP-A-59-175618 (JP, A) JP-A-63-82710 (JP , A) JP 64-16618 (JP, A) Actual development 56-173425 (JP, U) Actual public 43-23462 (JP, Y1) Actual public 49-17728 (JP, Y1)

Claims (1)

(57) [Claims] 1. A step of forming a cylindrical unvulcanized rubber material containing a foaming agent around a cored bar, and a step of setting the cylindrical unvulcanized rubber material to a cylindrical body having a lower mold. And, between the tubular unvulcanized rubber material and the tubular body, a step of filling one selected from a mixture of a thermoplastic powder and a thermoplastic powder and either an inorganic powder or an organic powder, An upper mold is fitted to the cylindrical body, and the cylindrical unvulcanized rubber material is pressurized and heated to foam and vulcanize, and the thermoplastic powder and any one of inorganic powder or organic powder are mixed with thermoplastic resin. A step of compressing and sintering one selected from a mixture with a powder.