JP2007062038A - Manufacturing method of rubber film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a rubber film capable of easily molding the rubber film having various patterns using inexpensive and simple equipment. <P>SOLUTION: The ribbon-shaped unvulcanized rubber supplied from an extruder is wound around a mandrel and, at this time, one of the relative moving speed in the axial direction of the mandrel with respect to the nozzle position of the extruder and at least one of the rotary direction or rotational speed of the mandrel are controlled to mold a cylindrical unvulcanized rubber film different in thickness and the cylindrical unvulcanized rubber film is cut along the axis of the mandrel to obtain a flat molded product before vulcanized and molded. The rubber film varied in thickness can be molded by controlling a rubber by controlling only the forward and backward rotation of the mandrel and the movement in the axial direction of the mandrel and the rubber film having various patterns can be molded by the inexpensive and simple equipment. Further, the ribbon-shaped unvulcanized rubber is extruded and the extrudate is wound around the mandrel to mold the rubber film having high thickness precision over its whole length. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

    The present invention relates to a method for producing a rubber film such as a rubber film for pressing used in a filter press.

  As shown in FIG. 4, the filter press includes a rubber film 1 for squeezing, a rigid plate 2, and a filter cloth 3. The filter press pressurizes the slurry injected into the filter cloth 3 from the back surface of the rubber film 1 and presses it against the rigid plate 2 to form a cake. The cake is put into the filter cloth 3 and the filtered liquid is a rubber for pressing. The slurry is caused to flow downward along the pattern groove of the membrane 1 to separate the slurry into solid and liquid.

  The rubber film 1 for pressing increases the surface pressure with the filter cloth 3 and the liquid squeezed out from the filter cloth 3 flows down to the pattern groove, so that the pattern groove is usually formed on the contact surface with the filter cloth 3. The pattern groove is set in various groove shapes such as a vertical groove, an oblique groove, or a dimple type, but the formation range of the pattern groove is a central contact cloth portion excluding the peripheral frame portion (patent) Reference 1 and Patent Reference 2).

  Usually, the solid-liquid separation of the slurry becomes a large-sized rubber membrane because the capability increases as the wetted area of the rubber membrane 1 for pressing increases. The size is a square shape of about 600 mm to 2200 mm, and is generally set to 1200 mm to 1800 mm.

The rubber film for pressing 1 is manufactured by arranging unvulcanized rubber plates in amounts slightly larger than their capacities on a mold engraved with pattern grooves and pressing them with a large press to vulcanize and mold them. It is common.
JP-A-5-103914 Japanese Patent Laid-Open No. 8-24517

  However, since the unvulcanized rubber plate that has been extruded and cooled once is placed in a mold and vulcanized, it takes a long time to vulcanize and mold the rubber plate to the center. Moreover, since vulcanization is performed from the surface of the rubber film for pressing, the vulcanized state may change between the surface and the central portion. This phenomenon becomes more prominent as the rubber thickness increases.

  In addition, it is difficult to accurately arrange a plurality of rubber plates at predetermined positions on the mold, and the rubber thickness is likely to vary. Further, since the rubbers are bonded together by heating, flowing, and fusing the rubber, the rubber does not flow uniformly over the entire surface, and the adhesive force varies.

  The above-mentioned drawbacks can be improved by increasing the shape of the rubber plate to some extent. However, when a large rubber plate is formed, the equipment becomes large, and the variation in thickness accuracy of the rubber plate increases. Cause problems.

  In view of the above, an object of the present invention is to provide a method of manufacturing a rubber film that can easily and accurately form a rubber film having various patterns with inexpensive and simple equipment.

  In order to achieve the above-mentioned object, the rubber film manufacturing method according to the present invention wraps a ribbon-like unvulcanized rubber supplied from an extruder around a mandrel, and at this time, the axial direction of the mandrel with respect to the nozzle position of the extruder By controlling at least one of the relative moving speed, rotational direction and rotational speed to the cylinder, cylindrical unvulcanized rubber films having different thicknesses are formed, and the cylindrical unvulcanized rubber film is formed into a mandrel. This is characterized in that it is cut along the axial direction of, and developed to form a flat plate and then vulcanized.

  In the above configuration, it is possible to form a rubber film with varying thickness by controlling only the forward / reverse rotation of the mandrel and the axial movement of the mandrel, and various patterns of rubber films can be formed with inexpensive and simple equipment. Can be molded. Further, by extruding a ribbon-like unvulcanized rubber and winding it around a mandrel, a rubber film with high thickness accuracy can be formed over the entire length.

  In addition, since the extruded rubber is molded only by the process of winding or sticking it onto a mandrel, there is no need for a manufacturing process such as preparation of rubber plates, cutting to the required size, and arranging unvulcanized rubber plates. Time can be shortened. Furthermore, since the extruded rubber is high temperature and can be vulcanized while maintaining the high temperature even after the molding is completed, the vulcanization molding time can be shortened, and the rubber film surface and the central portion can be further vulcanized. It is possible to provide a rubber film excellent in durability by eliminating the difference in the sulfur state.

  The unvulcanized rubber films having different thicknesses are formed by winding a ribbon-shaped unvulcanized rubber spirally to form a cylindrical first laminated rubber, and successively laminating the next laminated rubber thereon. Can be formed. In addition to the lamination method, unvulcanized rubber films having different thicknesses perform combined movement of the mandrel in the axial direction relative to the nozzle position of the extruder, and control of the rotational direction and rotational speed. Thus, it can be formed by a series of operations.

  Furthermore, if the rubber film is applied to a rubber film for squeezing a filter press in which a pattern groove is formed on one side, a rubber film with high thickness accuracy can be provided.

  As described above, according to the present invention, rubber films having different thicknesses can be easily formed by controlling any one or more of the rotation direction of the mandrel, the rotation speed, and the movement of the mandrel in the axial direction. In this case, a rubber film having various pattern grooves can be formed with inexpensive and simple equipment.

  Hereinafter, the manufacturing method of the rubber film for pressing of a filter press is demonstrated as embodiment of this invention. FIG. 1 is a perspective view showing a manufacturing process of a rubber film according to the present invention. FIG. 1A shows a first step of forming a cylindrical rubber cylinder 11 by spirally winding a ribbon-shaped rubber. The cylindrical rubber cylinder 11 is referred to as an entire rubber portion. FIG. 1B shows a second manufacturing process in which an island-shaped pattern rubber portion is formed by extruding a ribbon-shaped rubber on the entire rubber portion.

  The equipment for producing such a rubber film 1 includes a rubber extruder 5 and a mandrel 6 (see FIG. 1A). The nozzle 5 a of the rubber extruder 5 is disposed to face the peripheral surface of the mandrel 6, and is disposed at a position fixed to the mandrel 6 in the present embodiment. From the rubber extruder 5, a ribbon-like rubber is pushed out to the mandrel 6 side.

  The mandrel 6 is formed in a cylindrical shape, and a ribbon-like rubber 11 can be wound around the outer peripheral portion thereof. The mandrel 6 can rotate forward and backward around the axis center and can move in the axial direction.

  Next, a method for manufacturing the rubber film 1 will be described. First, as shown in FIG. 1A, a ribbon-like rubber 11 extruded from a nozzle 5 a of a rubber extruder 5 at a constant speed is wound around the outer peripheral surface of a mandrel 6. At this time, the mandrel 6 is rotated around the axis at a peripheral speed that exceeds the extrusion speed of the rubber 11 so that the ribbon-like rubber 11 does not bend. Further, by moving the mandrel 6 in the axial direction while extruding the rubber 11, the side ends 11 a of the rubber 11 do not overlap each other and are wound spirally while being in butt contact. The rubber wound in this manner is cylindrical and constitutes the base of the rubber film.

  Next, the ribbon-shaped rubber from the extruder 5 is further laminated on the entire rubber 13 to form island-shaped laminated rubber portions 14 and 15. At this time, by controlling any one or more of the rotation direction, rotation speed, and axial movement of the mandrel 6, the island-shaped laminated rubber portions 14, 15 are placed at the center of the main body excluding the frame portion 16. paste.

  The lamination rubbers 14 and 15 can be attached only with soft rubber immediately after extrusion. In order to increase the attaching accuracy, first, the entire rubber 13 is firmly attached to the mandrel 6 so that the position fluctuation does not occur when the entire rubber 13 is pressed. However, since the rubber immediately after extrusion is easily deformed when the pressing force is increased too much, the magnitude of the adhesive strength of the rubber is actually decisive. Natural rubber (NR) has high adhesiveness, but EPDM and NBR often used for rubber films for pressing have poor adhesiveness even at high temperatures. Therefore, when using rubber with low adhesive strength such as EPDM or NBR, it is preferable to add auxiliary means such as a presser roll.

  When the ribbon-like rubber 11 is wound around the entire rubber 13, and then the winding is finished, the ribbon-like rubber is torn off and the process proceeds to the next step. At this time, it is necessary to have a rubber adhesive force that can withstand the tearing force.

  As a condition satisfying the above, the entire rubber is preferably wound around the mandrel 6 by applying a tensile force of 10% to 30% elongation when extruding the ribbon-like rubber. Further, if the whole rubber 13 is at least at a temperature lower than the temperature at the time of extrusion and is from room temperature to 60 ° C., preferably from 40 ° C. to 50 ° C., it is optimal for obtaining the necessary adhesive strength.

  In the above process, the ribbon-like rubber is laminated in an island shape in the circumferential direction or the axial direction of the mandrel. However, the ribbon-like rubber may be inclined.

Basically,
A) Adjustment of the forward and reverse rotation direction of the mandrel B) Adjustment of the rotation speed of the mandrel,
C) Adjustment of the moving speed of the mandrel in the axial direction,
D) A rubber film is formed by a combined operation combining two or more of A), B) and C) above.

  Next, the cylindrical unvulcanized rubber film laminated as described above is cut along the axial direction of the mandrel 6 and developed to form the flat unvulcanized rubber film 1. The molded body of the unvulcanized rubber film is inserted into a vulcanization mold and vulcanized to complete the rubber film 1 for pressing.

  2 and 3 show an example of a flat rubber film. In the figure, L = 1000 mm, A = 100 mm, B = 600 mm, C = 80 mm, D = 700 mm, the thickness of the entire rubber portion as the first laminated rubber is 5 mm, the thickness of the second laminated rubber 14 is 3 mm, The laminated rubber 15 has a thickness of 6 mm, and a ribbon-like natural rubber (hardness JIS A 55 degrees) is extruded from the extruder 5. The extruded rubber has a width of 20 mm and a thickness of 2 mm, and is extruded and wound spirally to form the entire rubber portion 13. The entire rubber portion 13 is formed by winding a ribbon-like rubber 11 around the mandrel 6 in a spiral manner at a rotation speed of the mandrel 6 of 20 rpm and a moving speed of 2.5 mm / sec.

  The second laminated rubber 14 is laminated by adhering rubber by rotating the mandrel 6 twice every 120 sec at a moving speed of the mandrel 6 of 5 mm / sec.

  The third laminated rubber 15 switches the forward and reverse rotation of the mandrel 6 every 12 sec at a rotation speed of 4 rpm of the mandrel 6 and moves the mandrel 6 in the axial direction by 10 mm to wind and laminate the rubber.

  Next, the molding time, vulcanization time, adhesiveness, and thickness accuracy at the time of molding in the above embodiment were compared with a conventional method in which a rubber plate is placed in a mold and vulcanized. As a result, the molding time required 30 minutes (excluding the rubber plate extrusion time) for the rubber plate arrangement in the conventional method, whereas in the present invention, the ribbon-like rubber is spiraled around the mandrel by controlling the mandrel behavior. Since only the second laminated rubber 14 and the third laminated rubber 15 were laminated, the required time was 20 minutes.

  The vulcanization time required 60 minutes in the conventional method, whereas in the present invention, the high-temperature rubber immediately after extrusion was vulcanized as it was, and the process was completed in 30 minutes. Furthermore, the thickness accuracy at the time of molding was ± 1 mm in the conventional method, whereas in the present invention, since the island-like portions having different thicknesses are extruded by almost continuous rubber, the thickness accuracy is also good at ± 0.2 mm. Met.

  In addition, with respect to tackiness, in the conventional method, poor adhesion was observed between the rubber plates arranged, whereas in the present invention, poor adhesion can also be prevented, and air can be caught between the rubbers. Could also be prevented.

  Thus, in the present invention, the number of manufacturing steps can be reduced and the molding time can be shortened. Further, according to the present invention, there are excellent effects that the vulcanization time can be shortened and the dimensional accuracy of the molded product can be improved.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that many modifications and changes can be made within the scope of the present invention. For example, in the above embodiment, the nozzle position of the extruder is fixed and the mandrel is moved in the axial direction. However, the present invention is not limited thereto, and the nozzle of the extruder may be moved in the axial direction of the mandrel. Good. In the above embodiment, an example in which the entire rubber portion 13 is formed first, and then the second laminated rubber 14 and then the third laminated rubber 15 are sequentially laminated has been described. By controlling the extrusion speed and mandrel behavior (one or more of rotation direction, rotation speed, and axial movement), two or more parts with different thicknesses can be formed in a series of operations. You can also.

(A) is the perspective view which shows the 1st manufacturing process of the rubber film which concerns on this invention, and the same figure (b) respectively shows a 2nd manufacturing process. Conceptual diagram of a rubber membrane formed by cutting a cylindrical body into a flat plate shape Front sectional view of FIG. Principle of filter press

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rubber film for pressing 2 Rigid board 3 Filter cloth 5 Extruder 5a Nozzle 6 Mandrel 11 Ribbon rubber 13 Overall rubber (first laminated rubber)
14 Second laminated rubber 15 Third laminated rubber

Claims (4)

The ribbon-like unvulcanized rubber supplied from the extruder is wound around the mandrel, and at this time, at least one of the relative movement speed, rotation direction and rotation speed of the mandrel in the axial direction with respect to the nozzle position of the extruder is set. By controlling, to form a cylindrical unvulcanized rubber film having a different thickness, and cutting the cylindrical unvulcanized rubber film along the axial direction of the mandrel to obtain a flat molded body, A method for producing a rubber film, which is obtained by vulcanization molding. The unvulcanized rubber films having different thicknesses are formed by winding a ribbon-like unvulcanized rubber in a spiral shape to form a cylindrical first laminated rubber, and laminating the next laminated rubber thereon. The method for producing a rubber film according to claim 1. The unvulcanized rubber films having different thicknesses are formed by a series of operations by controlling the relative movement in the axial direction of the mandrel with respect to the nozzle position of the extruder, the rotation direction, and the rotation speed. The method for producing a rubber film according to claim 1. The method for producing a rubber film according to claim 1, wherein the rubber film is a rubber film for squeezing a filter press.

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