JP6422633B2 - Raw tire molding method - Google Patents

Description

  The present invention relates to a green tire molding method in which a green tire is molded using a strip-shaped rubber member for a tire.

  In general, when forming a raw tire, a so-called strip wind method is used in which a strip-shaped rubber member for rubber (rubber strip) such as tread rubber, sidewall rubber, and inner liner rubber is spirally wound around a wound body such as a molding drum. Is used (for example, Patent Document 1).

  Specifically, the rubber strip extruded into a predetermined shape from the extruder is transported using a transport conveyor, and thereafter, a green tire is formed by spirally winding the wound strip around the body to be wound.

  At this time, if the adhesiveness of the rubber strip is low, the rubber strip may collapse at the time of winding, and it may not be possible to wind it in a predetermined shape. In particular, a member having a large number of profiles such as a tread is difficult to form a profile according to specifications unless a certain level of adhesiveness can be secured.

  In addition, when the wound rubber strip is stitched down or the like, if the adhesiveness of the rubber strip is low, the stitch pressure may cause collapse (separation).

  For this reason, when forming a green tire, it is important to give the rubber strip sufficient adhesiveness, and various proposals have been made.

JP 2002-120302 A

  On the other hand, in recent years, tires are also strongly required to have low fuel consumption in response to requests for low fuel consumption of vehicles, and accordingly, rubber strips with low fuel consumption are also required for rubber strips. However, since a rubber strip with a low fuel consumption generally has low adhesiveness, a technique that can further improve the adhesiveness and form a green tire is desired.

  For this reason, the present invention provides a raw tire for forming a raw tire while stably securing sufficient adhesiveness, even for a rubber strip (strip-shaped tire rubber member) containing low fuel consumption and having low adhesiveness. It is an object to provide a molding method.

The invention described in claim 1
A raw tire molding method in which a strip-shaped rubber member for a tire extruded from an extruder is transported to a wound body on a conveyor and then wound around the wound body in a spiral manner to form a raw tire. And
The tire rubber member is made of a low-fuel-consumption rubber composition,
Using the transport conveyor having a surface roughness Ra of 0.7 to 2.5,
The tire rubber member extruded from the extruder is brought into close contact with the transport conveyor in a state where the surface temperature is 60 ° C. or higher, and then the tire rubber member is pressed using a pressing roller. The surface state of the conveyor is transferred to the tire rubber member by being pressed and adhered to the conveyor, thereby reducing the surface roughness of the tire rubber member. It is a green tire molding method characterized by improving adhesiveness.

The invention described in claim 2
The raw tire molding method according to claim 1, wherein the tire rubber member extruded from the extruder has a width of 5 to 40 mm and a thickness of 2.5 mm or less.

The invention according to claim 3
The raw tire molding method according to claim 1 or 2 , wherein the low fuel-consumption blended rubber composition is a rubber composition having a silica blending ratio of 10 parts by mass or more.

The invention according to claim 4
Adhesive strength of the tire rubber member having improved adhesiveness by being conveyed in close contact with the conveyor has any one of claims 1 to 3, characterized in that at least 1.5N 3. A method for forming a green tire according to 1.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a rubber strip (strip-shaped rubber member for tires) of the low fuel consumption mix | blend with low adhesiveness, shaping | molding of a raw tire which ensures sufficient adhesiveness stably and shape | molds a raw tire A method can be provided.

It is a figure explaining the shaping | molding method of the green tire which concerns on one embodiment of this invention.

  Hereinafter, the present invention will be described with reference to the drawings based on embodiments.

  FIG. 1 is a diagram for explaining a green tire molding method according to the present embodiment. In addition, in FIG. 1, 1 is an extruder, 2 is a conveyance conveyor, 3 is a pressing roller. G denotes a strip-shaped rubber member for a tire (rubber strip).

  In this embodiment, the rubber composition for tire is extruded into a predetermined strip shape on the conveyor 2 using the extruder 1 to form the rubber strip G, and then the rubber strip is used using the pressing roller 3. G is pressed onto the conveyor 2. Thereafter, the rubber strip G is conveyed to a molding drum (not shown) on the conveyor 2 and spirally wound around the molding drum to form a green tire.

  At this time, using the conveyor 2 having a surface roughness Ra of 0.7 to 2.5, the rubber strip G is pressed against and closely adhered to the conveyor 2 and conveyed.

  Thereby, the surface state of the contact surface of the conveyor 2 is transferred to the surface of the rubber strip G, the surface roughness of the rubber strip G is reduced, and the adhesiveness of the rubber strip G is improved. As a result, the rubber strip G can be wound with sufficient adhesive strength.

  In this embodiment, in order to transfer the small surface roughness Ra of the conveyor 2 to the rubber strip G in this way, in the present embodiment, the surface roughness (arithmetic) of the surface on the side in contact with the rubber strip G is determined as the conveyor 2. A transport conveyor having an average roughness Ra of 0.7 to 2.5 is used. In addition, said Ra is the value measured based on JISB0601 (1994) and JISB0031 (1994).

  When the surface roughness Ra of the conveyor 2 is less than 0.7, the rubber strip G and the conveyor 2 are too close to each other, and the rubber strip G is conveyed when the roll is wound around the forming drum. It cannot be removed smoothly from the conveyor 2. On the other hand, when it exceeds 2.5, since the rubber strip G and the conveyor 2 are not in close contact with each other, the rubber strip G may fall off the conveyor 2 during the conveyance of the rubber strip G. It is more preferable that it is 0.7-1.8.

  The surface roughness Ra of the transferred rubber strip G is preferably 0.5 to 2.0, and the rubber strip having such a surface roughness Ra has high adhesiveness.

  For improving the adhesiveness of such a rubber strip, conventionally, the adhesiveness has generally been improved by changing the composition of the rubber composition. However, the tackiness changes sensitively with temperature, etc., so even if the rubber composition is changed, if a certain level of tackiness is not secured, sufficient tackiness is obtained due to fluctuations in temperature, etc. There was a risk of being unable to do so. And there existed problems, such as the difficulty of the inventory adjustment corresponding to the cost increase accompanying a mixing | blending change, the fluctuation | variation of temperature, etc.

  Also, paying attention to the property of rubber that is generally plasticized and easily exhibits adhesiveness at high temperatures, it was also used to form green tires by winding while the temperature of the rubber strip was high. When the tire molding line is stopped due to a trouble or the like, the temperature of the rubber strip is lowered, so that the adhesiveness may be lowered.

  However, in the present embodiment, sufficient adhesiveness can be ensured by an extremely simple means of transferring the state of the contact surface of the conveyor 2 to the rubber strip G. It is not necessary to wind the strip while the temperature of the strip is high, and it is not necessary to consider changes in adhesiveness due to temperature fluctuations, difficulty in inventory adjustment, and cost increases associated with blending changes.

  The temperature of the rubber strip G when transferring the state of the contact surface of the conveyor 2 is preferably 60 ° C. or higher. When the temperature of the rubber strip G is less than 60 ° C., the state of the contact surface of the conveyor 2 is difficult to be transferred, and the adhesive force is not sufficiently improved.

  Further, when the rubber strip G and the conveyor 2 are brought into contact with each other, the conveyance speed by the conveyor 2 is slightly higher than the extrusion speed by the extruder 1, and tension is applied to the rubber strip G so that the width and thickness do not change. It is preferable to multiply. Thereby, the bending of the rubber strip G is prevented, and when the rubber strip G is pressed by the pressing roller 3, the rubber strip G can be brought into close contact with the transport conveyor 2 without any gap. Further, deformation of the rubber strip G can be suppressed.

  Moreover, it is preferable that the adhesive force of the rubber strip which improved the adhesiveness by closely_contact | adhering to the conveyance conveyor 2 is 1.5N or more. As a result, it is possible to more reliably prevent the falling from the conveyer and the collapse caused by the winding at the time of winding.

  Each effect in the present embodiment is remarkably exhibited when the rubber strip G extruded from the extruder 1 has a width of 5 to 40 mm and a thickness of 2.5 mm or less.

  In addition, when the rubber strip G is a rubber strip G made of a low-fuel-consumption blended rubber composition containing 10 parts by mass or more of silica, the adhesiveness is low, but by applying the present embodiment, sufficient adhesive strength can be obtained. Can be improved.

  In addition, it does not specifically limit as a shape of the rubber strip G in this Embodiment, Even if it is any general shape, such as a rectangular shape, a trapezoid, and a crescent moon shape, it can apply preferably.

  Since these rubber strips are transported on the transport conveyor with sufficient adhesive force, they do not fall off the transport conveyor during transport, and the occurrence of small stops in the tire molding line due to the rubber strip dropping is suppressed. The Further, since the rubber strip wound around the molding drum has a sufficient adhesive force, smooth winding can be performed, and the occurrence of variations during winding is suppressed. In addition, the occurrence of variations at the time of stitching down is suppressed.

  Next, based on an Example, this invention is demonstrated more concretely.

1. Raw tire molding Rubber strip for molding pneumatic tires with low fuel consumption of size 235 / 50R18, extruding and transporting rubber strips with a width of 23 mm, a thickness of 1.0 mm, and a trapezoidal cross section using an extruder The surface roughness Ra of the conveyor and the temperature (surface temperature) of the rubber strip were brought into contact with each other under the conditions shown in Table 1, respectively, and then pressed with a pressing roller to cause adhesion.

  Next, the rubber strip adhered to the conveyor was supplied to the forming drum and wound.

  The surface roughness Ra of the used conveyor and the surface roughness Ra of the rubber strip after being adhered to the conveyor were measured with a general-purpose surface roughness measuring instrument.

2. Evaluation (1) Evaluation Method The adhesiveness of the rubber strip was evaluated by the following method.

a. Measurement of Adhesive Strength A rubber strip onto which the state of the contact surface of the conveyor was transferred was sampled, and the adhesive strength was measured using a general-purpose tack meter. The measurement conditions are a compression load of 500 g, a measurement speed of 10 mm / sec, and a pressure bonding time of 10 seconds.

b. Investigation of the occurrence of breakage We investigated whether breakage caused by breakage occurred when the drum was wound or stitched down. When winding the drum, if the adhesion was too strong to wind the drum, it was evaluated that collapse occurred. Also, at the time of stitching down, if the adhesive strength of the rubber strip was low and flaking occurred, it was evaluated that collapse occurred.

(2) Evaluation results Table 1 shows the evaluation results.

From Table 1, when the surface roughness Ra of the conveyor is in the range of 0.7 to 2.5 and the surface temperature of the rubber strip is 60 ° C. or higher, the adhesive strength is high, and the drum is wound and stitched. It was confirmed that no collapse occurred during the down.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above embodiments. Various modifications can be made to the above-described embodiments within the same and equivalent scope as the present invention.

1 Extruder 2 Conveyor 3 Pressing roller G Rubber strip

Claims (4)

A raw tire molding method in which a strip-shaped rubber member for a tire extruded from an extruder is transported to a wound body on a conveyor and then wound around the wound body in a spiral manner to form a raw tire. And
The tire rubber member is made of a low-fuel-consumption rubber composition,
Using the transport conveyor having a surface roughness Ra of 0.7 to 2.5,
The tire rubber member extruded from the extruder is brought into close contact with the transport conveyor in a state where the surface temperature is 60 ° C. or higher, and then the tire rubber member is pressed using a pressing roller. The surface state of the conveyor is transferred to the tire rubber member by being pressed and adhered to the conveyor, thereby reducing the surface roughness of the tire rubber member. A method for forming a green tire, characterized by improving adhesiveness. The method for forming a raw tire according to claim 1, wherein the tire rubber member extruded from the extruder has a width of 5 to 40 mm and a thickness of 2.5 mm or less. The raw tire molding method according to claim 1 or 2 , wherein the low fuel consumption blended rubber composition is a rubber composition having a silica blending ratio of 10 parts by mass or more. Adhesive strength of the tire rubber member having improved adhesiveness by being conveyed in close contact with the conveyor has any one of claims 1 to 3, characterized in that at least 1.5N 2. A method for forming a green tire according to 1.

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