JP5761269B2 - Rubber roll manufacturing method - Google Patents

Description

The present invention relates to a rubber Muroru manufacturing method.

  Patent Document 1 states that “the moving speed of the cored bar in the die nozzle is changed in the lengthwise direction of the cored bar depending on the part such as one end part, the central part, the other end part, and the like. A method for manufacturing a rubber roller that changes the outer diameter of the unvulcanized rubber material along the longitudinal direction is disclosed.

Japanese Patent Laid-Open No. 2003-300279

The subject of this invention is providing the manufacturing method of the rubber roll which has an elastic layer excellent in shape accuracy from the initial stage of manufacture start.

  The above problem is solved by the following means.

The invention according to claim 1
A first step of supplying the core metal in the center of the unvulcanized rubber material that is extruded into a cylindrical shape to cover the outer peripheral surface of the core metal in the rubber material from the extrusion die of the extrusion unit having an extrusion die,
A second step of vulcanizing the rubber material covering the outer peripheral surface of the core metal;
Have
The extrusion die has a pressure (P0) when only the rubber material is extruded from the extrusion die and a pressure (P1) when the rubber material is extruded from the extrusion die in a state where the core metal is supplied. A method for producing a rubber roll having a land portion having a length satisfying the following formula (1).
Formula (1): −0.10 ≦ (P0−P1) /P0≦0.10

The invention according to claim 2
In the first step, the rubber with respect to the supply speed of the cored bar when the rubber material is coated on both ends in the axial direction of the cored bar than when the rubber material is coated on the axially central part of the cored bar. The method for producing a rubber roll according to claim 1 , wherein the relative extrusion speed of the material is increased.

According to the first aspect of the present invention, compared with the case where the extrusion die has a land portion having a length that does not satisfy the formula (1), the rubber roll having an elastic layer having excellent shape accuracy from the initial stage of production is obtained. A manufacturing method is provided.

According to the invention which concerns on Claim 2 , compared with the case where an extrusion die has the land part of the length which does not satisfy | fill Formula (1), the relative extrusion speed of the unvulcanized rubber material with respect to the supply speed | rate of a metal core is made. Even if it fluctuates, a method for producing a rubber roll having an elastic layer with excellent shape accuracy is provided from the initial stage of production.

It is a figure which shows the structure of the rubber roll manufacturing apparatus which concerns on this embodiment. It is a figure which shows the extrusion die of FIG. It is a figure which shows a mode that only a rubber material is extruded from the extrusion die of FIG. It is a figure which shows a mode that a rubber material is extruded in the state in which the metal core was supplied from the extrusion die of FIG.

  Hereinafter, an example of an embodiment of a rubber roll manufacturing apparatus and a rubber roll manufacturing method according to the present embodiment which is an example of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a configuration of a rubber roll manufacturing apparatus 10 according to the present embodiment.

  The rubber roll manufacturing apparatus 10 according to the present embodiment includes an extruder 12 constituted by a so-called cross head die and a control unit 11 for controlling each part in the apparatus.

  The extruder 12 includes a rubber material supply unit 18 that supplies an unvulcanized rubber material, an extrusion unit 20 that extrudes the rubber material supplied from the rubber material supply unit 18 in a cylindrical shape, and is extruded from the extrusion unit 20 into a cylindrical shape. And a metal core supply unit 24 for supplying the metal core 22 to the center of the rubber material.

The rubber material supply unit 18 has a screw 28 inside a cylindrical main body 26. The screw 28 is rotationally driven by a drive motor 30. On the drive motor 30 side of the main body portion 26, an insertion port 32 for introducing a rubber material is provided. The rubber material introduced from the insertion port 32 is sent out toward the extrusion part 20 while being kneaded by the screw 28 inside the main body part 26. By adjusting the rotational speed of the screw 28, the speed at which the rubber material is fed out is adjusted.
A pressure gauge 33 is disposed on the inner wall on the distal end side of the screw 28 in the cylindrical main body 26.

  The extrusion unit 20 includes a cylindrical case 34 connected to the rubber material supply unit 18, a columnar mandrel 36 disposed in the center of the case 34, and an extrusion die 38 disposed below the mandrel 36. I have. The mandrel 36 is held by the case 34 by a holding member 40. The extrusion die 38 is held on the case 34 by a holding member 42. Between the outer peripheral surface of the mandrel 36 (in part, the outer peripheral surface of the holding member 40) and the inner peripheral surface of the holding member 42 (in part, the inner peripheral surface of the extrusion die 38), an annular flow in which the rubber material flows annularly A path 44 is formed.

  An insertion hole 46 through which the core bar 22 is inserted is formed at the center of the mandrel 36. The lower part of the mandrel 36 has a tapered shape toward the end. A region below the tip of the mandrel 36 is a merge region 48 where the core metal 22 supplied from the insertion hole 46 and the rubber material supplied from the annular flow path 44 merge. That is, the rubber material is pushed out in a cylindrical shape toward the merging region 48, and the cored bar 22 is fed into the central portion of the rubber material pushed out in the cylindrical shape.

Here, as shown in FIG. 2, the extrusion die 38 has an inner peripheral surface that is inclined in the rubber material extrusion direction (the inner diameter is gradually narrowed toward the rubber material extrusion direction), and is in contact with the outer peripheral surface of the mandrel 36. A taper portion 38A in which an annular flow path 44 in which the rubber material flows annularly is formed, and is provided downstream of the taper portion 38A in the extrusion direction of the rubber material, and the inner peripheral surface is along the extrusion direction of the rubber material (inner diameter And a land portion 38B through which the cylindrical rubber material into which the cored bar 22 has been fed passes in the extrusion direction.
The land portion 38B may have a configuration in which the inner peripheral surface is inclined in the rubber material extrusion direction (the inner diameter is gradually narrowed toward the rubber material extrusion direction). However, in this case, the inner peripheral surface of the land portion 38B is an inner peripheral surface having an inclination angle smaller than the inclination angle of the inner peripheral surface of the tapered portion 38A with respect to the rubber material extrusion direction (supply direction of the core metal 22). .

  The cored bar supply unit 24 includes a roller pair 50 disposed above the mandrel 36. A plurality of pairs (for example, three pairs) of roller pairs 50 are provided, and one roller of each roller pair 50 is connected to a driving roller 54 via a belt 52. When the driving roller 54 is driven, the cored bar 22 held by each roller pair 50 is sent toward the insertion hole 46 of the mandrel 36. The core metal 22 has a predetermined length, and the rear core metal 22 fed by the roller pair 50 presses the front core metal 22 existing in the insertion hole 46 of the mandrel 36, whereby a plurality of core bars 22 are formed. Sequentially pass through the insertion hole 46. The driving of the driving roller 54 is temporarily stopped when the front end of the front cored bar 22 is positioned at the tip of the mandrel 36, and the cored bar 22 is moved in the junction area 48 below the mandrel 36. It is sent at intervals.

  As described above, in the extruder 12, the rubber material is extruded in a cylindrical shape in the merge area 48, and the cored bar 22 is sequentially fed to the central portion of the rubber material with an interval. Thereby, the rubber roll part 56 with which the outer peripheral surface of the metal core 22 is covered with a rubber material is pushed out from the extrusion die 38. In addition, a primer is applied in advance to the outer peripheral surface of the cored bar 22 in order to improve the adhesiveness with the rubber material.

  Then, the rubber roll which cut | disconnected by the boundary part of each metal core 22 of the rubber roll part 56 continuously extruded from the extrusion die 38 with the cutting machine which is not shown in figure, and coat | covered the outer peripheral surface of the metal core 22 with the unvulcanized rubber material. Get.

The control unit 11 is configured to control the operation of each unit of the rubber roll manufacturing apparatus 10.
Specifically, although not illustrated, the control unit 11 is configured as a computer, for example, a CPU (Central Processing Unit), various memories [for example, a RAM (Random Access Memory), a ROM (Read Only Memory), a nonvolatile memory] , And an input / output interface (I / O) are connected via a bus. Each part of the rubber roll manufacturing apparatus 10 such as a drive motor 30 that rotationally drives the screw 28, a drive motor (not shown) that rotationally drives the drive roller 54, and a pressure gauge 33 is connected to the I / O. .
The CPU executes, for example, a program (for example, a control program such as an extrusion molding program) stored in various memories, and controls the operation of each part of the rubber roll manufacturing apparatus 10. Note that the storage medium for storing the program executed by the CPU is not limited to various memories. For example, it may be a flexible disk, DVD disk, magneto-optical disk, USB memory (universal serial bus memory) or the like (not shown), or a storage device of another device connected to communication means (not shown). May be.

And when manufacturing a crown-shaped rubber roll, the control part 11 controls the supply speed | rate of the metal core 22, or the extrusion speed of a rubber material. Specifically, for example, when the cored bar 22 passes through the merging region 48, the supply speed of the cored bar 22 gradually decreases from the front end part to the central part of the cored bar 22, and the cored bar extends from the central part to the rear end part. A drive motor (not shown) that drives the drive roller 54 of the cored bar supply unit 24 is controlled so that the supply speed of 22 is gradually increased, and the rotational speed of the drive roller 254 is controlled. Alternatively, for example, when the cored bar 22 passes through the merge region 48, the rubber material extrusion speed gradually decreases from the front end part to the central part of the cored bar 22, and the rubber material extrusion speed increases from the central part to the rear end part. The drive motor 30 that drives the screw 28 of the rubber material supply unit 18 is controlled so as to gradually increase, and the rotational speed of the screw 28 is controlled.
By controlling the supply speed of the core metal 22 or the extrusion speed of the rubber material, the outer peripheral surface of the core metal 22 is covered with a rubber material so that the thickness of the central portion is larger than both end portions in the axial direction of the core metal 22. The rubber roll portion 56 is pushed out from the extrusion die 38.

  The rubber roll molded using the rubber roll manufacturing apparatus 10 according to the present embodiment described above is put in a vulcanization furnace in the next step. As a result, the rubber material covering the outer peripheral surface of the cored bar 22 of the rubber roll portion 56 is vulcanized. The vulcanized rubber roll is processed in the next step. Specifically, the rubber material at both ends is cut so that the cored bar 22 is exposed for a certain length at both ends of the rubber roll.

Here, in the rubber roll manufacturing apparatus 10 according to the present embodiment, prior to extruding the rubber roll portion 56 in which the outer peripheral surface of the metal core 22 is covered with the rubber material from the extrusion die 38, first, only the rubber material is extruded, and the rubber When the material starts to be extruded, the cored bar 22 is supplied and the rubber roll portion 56 is extruded. On the other hand, even if the rubber material is extruded from the extrusion die 38d, the outer diameter and shape of the rubber roll portion 56 are not stable because the speed of extrusion of the rubber material (extrusion speed) is not stable for a while. Even if the metal core 22 is supplied, the rubber roll part 56 having the desired outer diameter and shape cannot be obtained. In order to reduce the loss during this period, it is effective to continuously extrude only the rubber material without supplying the cored bar 22, to supply the cored bar 22 after the extrusion speed is stabilized, and to push out the rubber roll portion 56. .
However, also in this method, since the extrusion speed of the rubber material fluctuates for a while from the start of supply of the core metal 22 and the rubber roll portion 56 having the desired outer diameter and shape is not pushed out, the core metal 22 from the beginning. Loss of rubber material occurs, although not as much as when supplying.

  This phenomenon occurs when only the rubber material is extruded from the extrusion die 38 (see FIG. 3) and when the rubber material is extruded from the extrusion die 38 with the core metal 22 supplied (see FIG. 4). This is thought to be caused by the difference in the extrusion rate of the rubber material.

Therefore, in the rubber roll manufacturing apparatus 10 according to the present embodiment, the rubber material from the extrusion die 38 is supplied with the pressure (P0) and the core metal 22 being supplied when only the rubber material is extruded from the extrusion die 38 (see FIG. 3). The land portion having a length Lt that satisfies the expression (1) [preferably the expression (1-2), more preferably the expression (1-3)] in relation to the pressure (P1) when the pressure is extruded (see FIG. 4) An extrusion die 38 having 38B is used (see FIG. 2). That is, an extrusion die 38 having a land portion 38B having a length Lt in which the ratio of the difference between P0 and P1 with respect to P0 is −0.10 or more and 0.10 or less is used.
Formula (1): −0.10 ≦ (P0−P1) /P0≦0.10
Formula (1-2): −0.07 ≦ (P0−P1) /P0≦0.07
Formula (1-3): −0.05 ≦ (P0−P1) /P0≦0.05

  By using the extrusion die 38 having the land portion 38B having the length Lt satisfying the above formula (1), the difference in the extrusion speed of the rubber material is reduced, so that the stabilization of the extrusion speed of the rubber material is accelerated, and the rubber roll The outer diameter and shape of the rubber roll part 56 are stabilized from the initial stage of the extrusion start of the part 56. As a result, in the rubber roll manufacturing apparatus 10 according to the present embodiment, a rubber roll having an elastic layer with excellent shape accuracy is manufactured from the initial stage of manufacturing.

  It should be noted that the relative extrusion of the rubber material relative to the supply speed of the cored bar 22 when the rubber material is coated on both ends in the axial direction of the cored bar 22 than when the rubber material is coated on the axially central part of the cored bar 22. When the speed is increased, a rubber roll portion 56 having a shape (crown shape) in which the thickness of the rubber material (elastic layer) at the center portion in the axial direction is larger than both end portions in the axial direction is obtained. As described above, when producing a crown-shaped rubber roll by varying the relative extrusion speed of the rubber material with respect to the conveying speed of the cored bar 22, if the difference in the extrusion speed of the rubber material is large, the extrusion of the rubber material is particularly important. It takes time until the speed is stabilized, and it is difficult to obtain a crown-shaped rubber roll having a target shape profile from the initial stage of production. However, in the rubber roll manufacturing apparatus 10 according to the present embodiment, even if the relative extrusion speed of the rubber material with respect to the supply speed of the core metal is varied, the elastic roll having excellent shape accuracy is obtained from the initial stage of the manufacture. A rubber roll is produced.

The length Lt of the land portion 38B of the extrusion die 38 refers to the distance from the connecting portion with the taper portion 38A whose inner peripheral surface is inclined in the extrusion direction of the rubber material to the extrusion port end portion of the extrusion die 38 ( (See FIG. 2). If the length of the land portion 38B is too long, the pressure P0 of the rubber material tends to increase with respect to the pressure P1 of the rubber material. Conversely, if the length of the land portion 38B is too short, the pressure P1 of the rubber material The pressure P0 of the rubber material tends to decrease.
Specifically, the length Lt of the land portion 38B is preferably set in the range of 1 mm or more and 20 mm or less (preferably 4 mm or more and 10 mm or less) from the viewpoint of increasing the stabilization of the extrusion speed of the rubber material.

  The supply speed of the cored bar 22 is 100% or more and 120% or less (preferably 102% or more and 110% or less) with respect to the speed when the cored bar is not energized from the point of speeding up the stabilization of the extrusion speed of the rubber material. It is better to set the range.

The pressure (pressing force) P0 and P1 of each rubber material is preferably set in the range of 2 MPa or more and 30 MPa or less (preferably 5 MPa or more and 20 MPa or less) from the viewpoint of speeding up the stabilization of the extrusion speed of the rubber material.
The pressure (pressing force) P0 and P1 of each rubber material is the tip of the screw 28 in a cylindrical main body 26 (cylinder) in which a screw 28 for applying an extrusion pressure to the rubber material is disposed in the rubber roll manufacturing apparatus 10. It is a value measured by a pressure gauge 33 installed on the inner wall on the side.

  In addition, the Mooney viscosity ML1 + 4 (100 ° C .: JIS K 6300-1994) of the rubber material is set in the range of 5 or more and 100 or less (preferably 20 or more and 70 or less) in order to accelerate the stabilization of the extrusion speed of the rubber material. It is better.

Hereinafter, when the rubber roll manufacturing apparatus 10 equipped with the extrusion die 38 having the land portion 38B having the length Lt shown in Table 1 is used to supply the core metal, the rubber roll portion 56 is extruded, and a rubber roll is produced (P0− P1 / P0), the number of rubber rolls required from the start of production until the outer diameter and shape are stabilized. However, the other setting conditions of the rubber roll manufacturing apparatus 10 were as follows.
Note that it was determined that the outer diameter and shape of the rubber roll were stable from the start of production when the outer diameter was 2% or less of the average value of the outer diameters from the 100th to the 110th.

-Setting conditions-
Extrusion die 38: inner diameter of land portion 38B 12.5 mm
・ Core 22: Outer diameter 8mm, Length 354.5mm
Rubber material: Epichlorohydrin rubber (Mooney viscosity ML1 + 4 (100 ° C.) = 50)
-Supply speed of the core metal to the speed when the core metal is not energized = 105%

  From the above results, in the rubber roll manufacturing apparatus 10 according to the present embodiment, by using the extrusion die 38 having the land portion 38B having the length Lt that satisfies the above formula (1), the shape accuracy can be improved from the initial stage of manufacturing. It can be seen that a rubber roll having an excellent elastic layer is produced.

DESCRIPTION OF SYMBOLS 10 Rubber roll manufacturing apparatus, 11 Control part, 12 Extruder, 18 Rubber material supply part, 20 Extrusion part, 22 Core metal, 24 Core metal supply part, 33 Pressure gauge, 36 Mandrel, 38 Extrusion die, 38A Taper part, 38B Land Part, 56 Rubber roll part

Claims (2)

A first step of supplying the core metal in the center of the unvulcanized rubber material that is extruded into a cylindrical shape to cover the outer peripheral surface of the core metal in the rubber material from the extrusion die of the extrusion unit having an extrusion die,
A second step of vulcanizing the rubber material covering the outer peripheral surface of the core metal;
Have
The extrusion die has a pressure (P0) when only the rubber material is extruded from the extrusion die and a pressure (P1) when the rubber material is extruded from the extrusion die in a state where the core metal is supplied. A method for producing a rubber roll having a land portion having a length satisfying the following formula (1).
Formula (1): −0.10 ≦ (P0−P1) /P0≦0.10 In the first step, the rubber with respect to the supply speed of the cored bar when the rubber material is coated on both ends in the axial direction of the cored bar than when the rubber material is coated on the axially central part of the cored bar. The method for producing a rubber roll according to claim 1 , wherein the relative extrusion speed of the material is increased.

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