JP7372533B2 - Release treatment method and system for tire curing bladder - Google Patents

Description

The present invention relates to a mold release treatment method and system for a tire curing bladder, and more particularly, to a method and system for mold release treatment of a tire curing bladder, and more particularly, to maintain the mold release properties of the outer surface of the tire curing bladder while making it possible to use this bladder for a longer period of time. The present invention relates to a mold release treatment method and system for a tire curing bladder.

A release agent is applied to the outer surface of the bladder in order to prevent the inner surface of the vulcanized tire from coming into close contact with the tire curing bladder and to smoothly take out the vulcanized tire. This mold release agent peels off when vulcanization is repeated. Therefore, in order to coat the outer surface of the bladder with a mold release agent with good adhesion, it has been proposed to perform plasma surface treatment on this outer surface and then apply the mold release agent (see Patent Document 1).

By modifying the outer surface of the bladder by plasma surface treatment, the applied mold release agent becomes difficult to peel off from this outer surface. However, simply performing plasma surface treatment causes variations in the degree of modification of the outer surface of the bladder, resulting in scattered areas on the outer surface of the bladder where the mold release agent is quickly peeled off. Therefore, there is room for improvement in order to use this bladder for a longer period of time while maintaining the mold releasability of the outer surface of the bladder.

Japanese Patent Application Publication No. 2009-83466

An object of the present invention is to provide a mold release treatment method and system for a tire vulcanizing bladder, which allows the bladder to be used for a longer period of time while maintaining the mold releasability of the outer surface of the tire vulcanizing bladder. There is a particular thing.

In order to achieve the above object, the mold release treatment method for a tire curing bladder of the present invention involves irradiating a target range of the outer surface of a tire curing bladder with plasma to modify the modified outer surface. In a mold release treatment method for a tire curing bladder in which the outside is coated with a mold release agent, the bladder is maintained in a predetermined inflated state that eliminates wrinkles on the outer surface caused by contraction of the bladder, and While maintaining the distance between the outer surface of the bladder in an expanded state and the nozzle tip that irradiates the plasma within a predetermined constant range, the target range of the outer surface is kept within a predetermined temperature range from the nozzle tip. The method is characterized in that the plasma is irradiated.

The mold release treatment system for a tire vulcanizing bladder of the present invention includes a plasma irradiation device that irradiates plasma onto a target range of the outer surface of a tire vulcanizing bladder, and a plasma irradiation device that releases plasma from the outside of the outer surface modified by the plasma. In a mold release treatment system for a tire vulcanizing bladder, which includes a release agent application device for coating with a mold agent, the bladder is brought into a predetermined inflated state to eliminate wrinkles on the outer surface caused by contraction of the bladder. an expansion maintaining mechanism for maintaining the distance between the outer surface of the bladder in the predetermined expanded state and the nozzle tip that irradiates the plasma within a predetermined constant range; It is characterized by having an outer surface temperature control mechanism that sets the target range of the outer surface to a predetermined temperature range when the target range of the outer surface is irradiated with the plasma.

According to the present invention, when the outer surface of the bladder is modified by plasma, the bladder is maintained in a predetermined expanded state to eliminate wrinkles on the outer surface caused by contraction of the bladder, and the predetermined expansion is Plasma is irradiated from the nozzle tip while maintaining the distance between the outer surface of the bladder and the nozzle tip that irradiates plasma within a predetermined constant range. This suppresses variations in the degree of modification of the outer surface of the bladder by the plasma, and makes it difficult to form regions on the outer surface of the bladder where the release agent peels off early. As a result, the bladder can be used for a longer period of time while maintaining the release properties of the outer surface of the bladder.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram illustrating a tire vulcanizing bladder, seen from the front, which has been subjected to mold release treatment according to the present invention. FIG. 2 is an explanatory diagram illustrating the tire curing bladder of FIG. 1 in a plan view. 3 is a sectional view taken along line AA in FIG. 2. FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram illustrating a part of an embodiment of a mold release treatment system for a tire curing bladder of the present invention in a front view. FIG. 5 is an explanatory diagram illustrating the mold release processing system of FIG. 4 in a plan view. FIG. 5 is a front view illustrating a state in which the outer surface of the bladder of FIG. 4 has wrinkles. 5 is an explanatory diagram showing a modification of the irradiation nozzle of FIG. 4. FIG. FIG. 3 is an explanatory diagram illustrating another embodiment of the mold release processing system in a front view.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method and system for releasing a tire curing bladder according to the present invention will be described based on an embodiment shown in the drawings.

The tire curing bladder 21 (hereinafter referred to as the bladder 21) illustrated in FIGS. 1 to 3 has been subjected to mold release treatment in which the outer surface 22a is coated with a mold release agent L using the present invention. The bladder 21 is a cylindrical body having a cylindrical main body 22 and opening edges 23 at both ends of the main body 22 . Each opening edge 23 is formed thicker than the main body 22.

The target range of the outer surface 22a has been modified (wettability has been improved) by the plasma Z, as will be described later, and the modified range is covered with the primer P. The coating layer made of the primer P (primer layer) is coated with a mold release agent L. A known liquid mold release agent L, such as a silicone liquid of a predetermined concentration diluted with water, is used.

The primer P is an adhesive that more firmly bonds the outer surface 22a and the mold release agent L, and specifications suitable for both are selected through preliminary tests and the like. Since the primer layer can be optionally provided, it is also possible to directly coat the outer surface 22a with the release agent L to form a coating layer (release layer) of the release layer L on the outer surface 22a. .

When the outer surface 22a of the bladder 21 is subjected to mold release treatment, the bladder 21 is held by the holding part 3. The holding part 3 has a central shaft 5 that passes through the bladder 21 in the axial direction, and two sets of a holding plate 4A and a holding ring 4B.

The central shaft 5 has both ends closed, a pressurizing line 7 to be described later can be connected to one end, and a through hole 5a is provided halfway in the axial direction. A dashed-dotted line CL in the figure indicates the axis of the central shaft 5. The sets of the holding plate 4A and the holding ring 4B are attached to the central shaft 5 at intervals in the axial direction. Each opening edge 23 is held between the holding plate 4A and the holding ring 4B.

The tire curing bladder mold release treatment system 1 (hereinafter referred to as treatment system 1) of the present invention illustrated in FIGS. 4 and 5 includes a plasma irradiation device 8, a release agent application device 11, and an expansion maintenance mechanism ( The control unit 20 controls the operations of the plasma irradiation device 8, the release agent application device 11, and the expansion maintenance mechanism (pressure line 7).

In this embodiment, since the outer surface 22 is coated with the primer P, it has a primer application device 14, and further has an outer surface temperature control mechanism 17 that adjusts the outer surface 22 to a desired temperature. The operations of the primer application device 14 and the outer surface temperature control mechanism 17 are controlled by the control section 20. Primer application device 14 and outer surface temperature control mechanism 17 can be provided as desired.

The holding part 3 holding the bladder 21 is attached to a beam part 2b extending horizontally from the support column 2a of the support frame 2. The central shaft 5 is rotatably held by the beam portion 2b. A rotary drive motor 6 is attached to another beam portion 2b. The central shaft 5 is rotationally driven by a rotational drive motor 6. Accordingly, the bladder 21 rotates around the central axis 5. The operation of the rotary drive motor 6 is controlled by a control section 20. Although the outer surface temperature control mechanism 17 is attached to the support column 2a, it can also be attached to another member or a different position.

As illustrated in FIG. 5, the holding part 3 holding the bladder 21 has a structure that allows it to rotate around the axial direction (extending direction) of the support column 2a. The operation of this rotational movement is also controlled by the control section 20. The plasma irradiation device 8, the primer application device 14, and the mold release agent application device 11 are arranged at intervals with the pillar 2a as the center in a plan view. Therefore, the bladder 21 can be sequentially moved to the steps performed by each of the plasma irradiation device 8, the primer application device 14, and the release agent application device 11.

In order to sequentially move the bladder 21 to the steps using the plasma irradiation device 8, the primer application device 14, and the mold release agent application device 11, various mechanisms other than the configuration illustrated in this embodiment can be used. For example, a robot arm or a moving device that moves along a guide can be used.

The plasma irradiation device 9 performs a modification step of irradiating a target range of the outer surface 22a with plasma Z to activate the outer surface 22a. The plasma irradiation device 9 includes a plasma generator 9a, an irradiation nozzle 9b that irradiates plasma Z, and a nozzle moving mechanism 10 that moves the irradiation nozzle 9b to a desired position. The nozzle moving mechanism 10 includes a plurality of arms 10a and a rotary joint 10b that rotatably connects the arms 10a. The nozzle moving mechanism 10 functions as a spacing maintenance mechanism as described later.

As the plasma Z to be used, thermal equilibrium plasma (thermal plasma) or non-thermal equilibrium plasma (low temperature plasma) can be used. In thermal equilibrium plasma, the mean free path of particles is short at atmospheric pressure and collisions are repeated, so there is a risk that the outer surface 22a may be damaged by heat, but the reforming effect is high. In a non-thermal equilibrium plasma, under low pressure (negative pressure) such as a vacuum, there is little interaction such as collision of particles, and there is no risk of damage to the outer surface 22a due to heat, but the apparatus becomes large-scale. For example, a dielectric is disposed on at least one of the parallel plate electrodes, and an alternating current or pulse voltage is applied between the electrodes to generate a dielectric barrier discharge. Dielectric barrier discharge is always a pulsed discharge, suppresses Joule heat, and can obtain a stable atmospheric pressure non-thermal parallel plasma, so it is preferable to use this plasma Z. The intensity of the plasma Z (the magnitude of the applied voltage) is set within the appropriate range after a preliminary test is conducted to determine the appropriate range.

The mold release agent applying device 11 performs a mold release agent coating step in which the outside of the outer surface 22a modified by the irradiated plasma Z is coated with the mold release agent L. In this embodiment, a release layer is formed on a primer layer formed of primer P. The mold release agent applying device 11 includes a supply source of the mold release agent L, a coating nozzle 12 that discharges the mold release agent L, and a nozzle moving mechanism 13 that moves the coating nozzle 12 to a desired position. The nozzle moving mechanism 13 includes a plurality of arms 13a and a rotary joint 13b that rotatably connects the arms 13a.

The primer application device 14 performs a primer coating step of coating the outer surface 22a modified by the irradiated plasma Z with a primer P. The primer applying device 14 includes a supply source of the primer P, a coating nozzle 15 that discharges the primer P, and a nozzle moving mechanism 16 that moves the coating nozzle 15 to a desired position. The nozzle moving mechanism 16 includes a plurality of arms 16a and a rotary joint 16b that rotatably connects the arms 16a.

The expansion maintaining mechanism includes a pressurizing line 7 , a pressurizing medium supply source connected to the pressurizing line 7 , and a regulating valve provided in the pressurizing line 7 . A pressurized medium such as air or nitrogen gas is supplied into the bladder 21 from a pressurized medium supply source through a pressurizing line 7 . By controlling the degree of opening of the regulating valve by the control unit 20, the degree of expansion of the bladder 21 is adjusted.

The outer surface temperature control mechanism 17 maintains the outer surface 22a within a temperature range where it is easy to activate (modify) the outer surface 22a. The temperature range in which it is easy to activate (modify) the outer surface 22a is known in advance by conducting a preliminary test or the like.

As illustrated in FIG. 6, when the bladder 21 contracts, wrinkles W are generated on the outer surface 22a. The expansion maintaining mechanism (pressure line 7, etc.) maintains the bladder 21 in a predetermined expanded state that eliminates wrinkles W on the outer surface 22a caused by contraction of the bladder 21. This predetermined degree of expansion is determined in advance by conducting a preliminary test or the like. That is, the bladder internal pressure that causes the bladder 21 to be inflated to a predetermined degree is known in advance. The bladder internal pressure is preferably 0.05 Pa or less, for example.

The distance maintaining mechanism 10 maintains the distance d between the outer surface 22a of the bladder 21 in a predetermined expanded state and the tip of the irradiation nozzle 9b within a predetermined constant range. In this embodiment, the nozzle moving mechanism 10 controlled by the control unit 20 functions as the spacing fiber mechanism 10. This predetermined constant distance is determined in advance by conducting a preliminary test or the like. This predetermined constant distance is, for example, about 0 mm to 30 mm. A distance sensor that sequentially detects the distance d between the outer surface 22a and the tip of the irradiation nozzle 9b may be used to maintain the distance d within a predetermined constant range. This predetermined fixed distance varies depending on the intensity of the plasma P, the moving speed of the irradiation nozzle 9b, etc., but is, for example, about 1 mm/s to 100 mm/s.

Next, a method of releasing the outer surface 22a of the bladder 21 will be described.

First, as illustrated in FIGS. 4 and 5, the holding part 3 holding the bladder 21 is attached to the support frame 2. A pressure line 7 is connected to the central shaft 5. A pressurized medium is supplied to the central shaft 5 through a pressurizing line 7. The supplied pressurized medium is discharged into the bladder 21 from the through hole 5a and applies internal pressure to the bladder 21. Thereby, the bladder 21 is maintained in a predetermined expanded state that eliminates the wrinkles W on the outer surface 22a caused by the contraction of the bladder 21. Further, the outer surface temperature control mechanism 17 is operated as necessary to heat the outer surface 22a to, for example, about 50 to 100°C.

Next, by controlling the nozzle moving mechanism 10, plasma is discharged from the tip of the irradiation nozzle 9b while maintaining the distance d between the outer surface 22a of the bladder 21 in a predetermined expanded state and the tip of the irradiation nozzle 9b within a predetermined constant range. Irradiate Z. At this time, the bladder 21 is rotated around the central axis 5. Further, the irradiation nozzle 9b is moved up and down by the nozzle moving mechanism 10, and the plasma Z is irradiated under atmospheric pressure so as to cover the target range of the outer surface 22a.

The target range of the outer surface 22a irradiated with the plasma Z is activated (modified), and the water contact angle becomes small, making it easier to firmly adhere the primer P and the mold release agent L. Since the outer surface 22a is in a predetermined expanded state in which the wrinkles W mentioned above have disappeared, and the above-mentioned distance d is maintained within a predetermined constant range, the degree of modification of the outer surface 22a by the plasma Z can be controlled. Variations are suppressed, and the target range has a generally homogeneous modification state. Furthermore, by maintaining the outer surface 22a within a temperature range where it is easy to activate (modify) the outer surface 22a using the outer surface temperature control mechanism 17, it becomes possible to carry out the modification more quickly and stably.

After the modification step, the bladder 21 is moved to the primer coating step. In this step, while rotating the bladder 21 about the central axis 5, the coating nozzle 15 is moved up and down by the nozzle moving mechanism 16, and the primer P is applied so as to cover the target range of the modified outer surface 22a. Apply by spraying. The distance between the outer surface 22a of the bladder 21 in a predetermined inflated state and the tip of the coating nozzle 15 is preferably maintained within an appropriate predetermined constant range.

After the primer coating step, the bladder 21 is moved to the release agent coating step. In this step, while rotating the bladder 21 around the central axis 5, the coating nozzle 12 is moved up and down by the nozzle moving mechanism 13, and separated so as to cover the target range of the outer surface 22a coated with the primer P. Apply molding agent L by spraying. The distance between the outer surface 22a of the bladder 21 in a predetermined inflated state and the tip of the application nozzle 12 is preferably maintained within an appropriate predetermined constant range.

Through the above-described modification step, primer coating step, and release agent coating step, the release agent L firmly adheres to the modified outer surface 22a almost uniformly via the primer P. As a result, a region where the mold release agent L is quickly peeled off is less likely to occur on the outer surface 22a, and it becomes possible to use the bladder 21 for a longer period of time while maintaining the mold releasability of the outer surface 22a.

Even if the primer P is not used, if the mold release agent L can be firmly attached to the modified outer surface 22a, the primer P can be omitted. In this embodiment, a robot arm is used as the nozzle moving mechanism 10, but the present invention is not limited to this.

As illustrated in FIG. 7, it is also possible to use a nozzle moving mechanism 10 that includes a roller 10c that moves forward and backward using a biasing member such as a spring. On both sides of the irradiation nozzle 9b, rollers 10c that move forward and backward independently of each other with respect to the outer surface 22a are installed. Each roller 10c rolls against the outer surface 22a. Each roller 10c is tuned so that the distance d between the outer surface 22a and the tip of the irradiation nozzle 9b can be maintained within a predetermined constant range by moving back and forth along the contour of the outer surface 22a. Therefore, the distance d is maintained within a predetermined constant range also at the shoulder portion (vertical section curved portion) of the outer surface 22a. Accordingly, the degree of modification of the cylindrical curved outer surface 22a of the main body portion 22 and the dome-shaped curved outer surface 22a can be easily made equal.

In order to bring the bladder 21 into a predetermined expanded state, the processing system 1 may be provided with an expansion maintenance mechanism including a casing 18 and a vacuum pump 19, as in the embodiment illustrated in FIG. The operation of the vacuum pump 19 is controlled by a control section 20.

In this embodiment, a bladder 21 is housed internally in the casing 18. Then, the space outside the bladder 21 inside the casing 18 is made negative pressure by the vacuum pump 19. In this manner, the interior of the casing 18 is evacuated using the vacuum pump 19 to create a negative pressure, thereby maintaining the bladder 21 in a predetermined expanded state. The casing 18 and the vacuum pump 19 can be provided not only in place of the pressurizing line 7, but also in addition to the pressurizing line 7. For example, the bladder 21 can be maintained in a predetermined expanded state by operating the casing 18, the vacuum pump 19, and the pressurizing line 7, respectively.

In the embodiment described above, the bladder 21 is rotated around the central axis 5 in each step, but the nozzle moving mechanisms 10, 13, 16 are rotated around the central axis 5 without rotating the bladder 21. Each process can also be performed by moving in the circumferential direction of 21. Alternatively, each process can be performed by rotating the bladder 21 around the central axis 5 and moving the nozzle moving mechanisms 10, 13, 16 in the circumferential direction of the bladder 21 around the central axis 5.

For general tire vulcanization, atmospheric pressure non-thermal parallel plasma is produced by placing a dielectric on at least one of the parallel plate electrodes and applying an alternating current voltage between the electrodes to generate a dielectric barrier discharge. After modifying the outer surface of the bladder, a mold release agent was applied, and the wettability after modification and the durability of the mold release layer due to the mold release agent (a prescribed rubbing test on the mold release layer) were evaluated. In the modification process, the outer surface of the bladder was It was maintained at a predetermined expanded state in which wrinkles caused by shrinkage disappeared. The elongation of the outer surface in this predetermined expanded state was about 100% to 150%.

As a result of the evaluation, when the distance d was about 5 mm to 10 mm and the moving speed was about 20 mm/s or less, the wettability was improved (the degree of modification was good) and the durability of the mold releasability was also good.

1 Processing system 2 Support frame 2a Support columns 2b, 2c Beam section 3 Holding section 4A Holding plate 4B Holding ring 5 Central shaft 5a Through hole 6 Rotary drive motor 7 Pressure line (expansion maintenance mechanism)
8 Plasma irradiation device 9a Plasma generator 9b Irradiation nozzle 10 Nozzle movement mechanism (interval maintenance mechanism)
10a Arm 10b Rotating joint 11 Release agent applying device 12 Coating nozzle 13 Nozzle moving mechanism 13a Arm 13b Rotating joint 14 Primer applying device 15 Coating nozzle 16 Nozzle moving mechanism 16a Arm 16b Rotating joint 17 Outer surface temperature control mechanism 18 Casing (expansion maintenance mechanism)
19 Vacuum pump (expansion maintenance mechanism)
20 Control part 21 Vulcanizing bladder 22 Main body part 22a Outer surface 23 Opening edge L Mold release agent P Primer W Wrinkle Z Plasma

Claims (6)

In a mold release treatment method for a tire vulcanizing bladder, the method comprises irradiating a target range of the outer surface of the tire vulcanizing bladder with plasma to modify it, and coating the outside of the modified outer surface with a mold release agent,
The bladder is maintained in a predetermined expanded state that eliminates wrinkles on the outer surface caused by contraction of the bladder, and the distance between the outer surface of the bladder in the predetermined expanded state and the tip of the nozzle that irradiates the plasma. A mold release treatment method for a tire curing bladder, characterized in that the plasma is irradiated from the nozzle tip while keeping the target range of the outer surface within a predetermined temperature range. . 2. The method for releasing a tire curing bladder according to claim 1, wherein the bladder is brought into the predetermined inflated state by applying internal pressure to the bladder. The tire vulcanization according to claim 1 or 2, wherein the bladder is placed in the predetermined inflated state by housing the bladder in a casing and creating a negative pressure in a space outside the bladder inside the casing. Mold release treatment method for plastic bladders. The mold release treatment method for a tire vulcanizing bladder according to any one of claims 1 to 3, wherein a mold release agent is applied to the outer surface after a primer is applied to the outer surface modified by irradiation with the plasma. . The release agent for a tire vulcanizing bladder according to any one of claims 1 to 4, wherein the outside of the outer surface is coated with the release agent after applying a primer to the outer surface modified by irradiating the plasma. Type handling method. A tire comprising a plasma irradiation device that irradiates plasma onto a target range of the outer surface of a tire curing bladder, and a release agent applying device that coats the outside of the outer surface modified by the plasma with a release agent. In the mold release treatment system for vulcanizing bladders,
an expansion maintenance mechanism that maintains the bladder in a predetermined expanded state that eliminates wrinkles on the outer surface caused by contraction of the bladder; and a nozzle that irradiates the outer surface of the bladder in the predetermined expanded state with the plasma. a distance maintenance mechanism that maintains a distance from the tip within a predetermined constant range; and a distance maintaining mechanism that maintains the target range of the outer surface in a predetermined temperature range when irradiating the plasma to the target range of the outer surface in the predetermined expanded state. 1. A mold release treatment system for a tire curing bladder, characterized by having an outer surface temperature control mechanism .

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