JP2018103495A - Method of producing non-pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a non-pneumatic tire capable of suppressing generation of voids and improving durability.SOLUTION: A method for producing a non-pneumatic tire comprising a thermosetting resin, contains a step of preparing a raw material liquid of the thermosetting resin such that a liquid viscosity is 600 to 6000 mPa s, a step of agitating and defoaming the raw material liquid of the thermosetting resin prepared, and a step of injecting the defoamed raw material liquid of the thermosetting resin into a mold and curing the same.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a non-pneumatic tire made of a thermosetting resin.

  The pneumatic tire has a load supporting function, a shock absorbing ability from the ground contact surface, and a transmission ability (acceleration, stop, change of direction) such as power. For this reason, many vehicles, particularly bicycles, motorcycles, automobiles, It is used in trucks.

  In particular, these capabilities greatly contributed to the development of automobiles and other motor vehicles. Furthermore, the impact absorbing ability of pneumatic tires is useful for medical equipment and electronic equipment transport carts and other applications.

  Conventional non-pneumatic tires include, for example, solid tires, spring tires, cushion tires, and the like, but do not have the superior performance of pneumatic tires. For example, solid tires and cushion tires support the load by compressing the contact portion, but this type of tire is heavy and stiff, and does not have the ability to absorb shock like a pneumatic tire. Further, in the non-pneumatic tire, it is possible to improve the cushioning property by increasing the elasticity, but there is a problem that the load supporting ability or the durability as the pneumatic tire has is deteriorated.

  As a non-pneumatic tire, for example, Patent Document 1 below describes a non-pneumatic tire including an outer annular portion and a plurality of spokes that extend radially inward from the outer annular portion and are fixed to a wheel. . Spokes are formed by pouring polyurethane liquid into a rotating mold.

  Further, Patent Document 2 below describes a non-pneumatic tire using a composite cylinder having fibers embedded in a resin base material as a reinforcing element.

  Patent Document 3 below describes a non-pneumatic tire including an inner annular portion, an outer annular portion, and a support structure that connects the inner annular portion and the outer annular portion. This non-pneumatic tire is made of polyurethane or the like.

  The non-pneumatic tires of Patent Documents 1 to 3 are made of a resin material such as polyurethane, but Patent Documents 1 to 3 do not disclose details about the physical properties of the resin material. Depending on the physical properties and curing behavior of the resin material used, bubbles (voids) may remain in the resin material, which may adversely affect durability.

Special table 2014-507111 gazette JP 2010-535866 Gazette JP-T-2006-506318

  Therefore, an object of the present invention is to provide a method for manufacturing a non-pneumatic tire that can suppress the generation of voids and improve durability.

The above object can be achieved by the present invention as described below.
That is, the non-pneumatic tire manufacturing method of the present invention is a non-pneumatic tire manufacturing method composed of a thermosetting resin,
Adjusting the raw material liquid of the thermosetting resin so that the liquid viscosity is 600 to 6000 mPa · s;
A step of stirring and defoaming the adjusted raw material liquid of the thermosetting resin;
And a step of injecting and curing the defoamed raw material liquid of the thermosetting resin into a mold.

  By setting the liquid viscosity to 600 to 6000 mPa · s, it is difficult to chew bubbles and the bubbles are easily removed in the step of stirring and defoaming the raw material liquid of the thermosetting resin. Thereby, when the raw material liquid of the thermosetting resin is injected into the mold and cured, generation of voids is suppressed, and as a result, durability can be improved.

  In the non-pneumatic tire manufacturing method according to the present invention, in the step of stirring and defoaming the thermosetting resin raw material liquid, it is preferable to stir using a rotation / revolution mixer.

  By using a rotation / revolution mixer, the raw material liquid of the thermosetting resin can be stirred while effectively removing bubbles.

  In the method for producing a non-pneumatic tire according to the present invention, in the step of stirring and defoaming the raw material liquid of the thermosetting resin, the rotation speed is 700 rpm or more and the rotation speed is 400 rpm or more using a rotation / revolution mixer. In addition, it is preferable that the stirring time is 1 minute or longer.

  By stirring the thermosetting resin using a rotating / revolving mixer under these conditions, the raw material liquid of the thermosetting resin can be stirred while effectively removing bubbles.

Flow chart showing an example of manufacturing process of non-pneumatic tire Front view showing an example of non-pneumatic tire (A) which shows the metal mold | die for shape | molding a support structure is a front view, (b) is a longitudinal cross-sectional view

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a flowchart showing an example of a manufacturing process of a method for manufacturing a non-pneumatic tire according to the present invention. FIG. 2 is a front view showing an example of the non-pneumatic tire T. FIG. FIG. 3 shows a mold for molding the support structure SS, and (a) is a front view and (b) is a longitudinal sectional view.

  The non-pneumatic tire T of the present embodiment includes a support structure SS that supports a load from the vehicle. The support structure SS includes an inner annular portion 1, an intermediate annular portion 2 provided concentrically on the outer side, an outer annular portion 3 provided concentrically on the outer side, the inner annular portion 1 and the intermediate annular portion. 2 and a plurality of inner connecting portions 4 that are independent in the circumferential direction, and a plurality of outer connecting portions 5 that are connected to the outer annular portion 3 and the intermediate annular portion 2 and are independent in the circumferential direction. In this embodiment, the support structure SS includes the intermediate annular portion 2, but the intermediate annular portion 2 is not always necessary, and the intermediate annular portion 2 is not provided, and the inner connecting portion 4 and the outer connecting portion 5 are continuous. Thus, one connecting portion may be configured. The non-pneumatic tire T may include a belt layer 6, a tread layer 7, and the like on the outer peripheral side of the support structure SS as shown in FIG.

  The support structure SS (the inner annular portion 1, the intermediate annular portion 2, the outer annular portion 3, the inner coupling portion 4, and the outer coupling portion 5) is basically integrated with the same thermosetting resin except for the reinforcing structure. To be molded.

  The method for producing a non-pneumatic tire according to the present invention is to produce a non-pneumatic tire composed of a thermosetting resin by injecting a thermosetting resin raw material liquid into a mold and curing it. Examples of the thermosetting resin include an epoxy resin, a phenol resin, a polyurethane resin, a silicon resin, a polyimide resin, and a melamine resin.

  Of the above thermosetting resins, a polyurethane resin is preferably used from the viewpoint of moldability / workability and cost. Among polyurethane resins, those using paraphenylene diisocyanate (PPDI) as the isocyanate component of the main raw material are particularly preferable. Polyurethane resins using PPDI have excellent bending fatigue resistance and hydrolysis resistance. Polyurethane resins using PPDI have lower exothermicity due to hysteresis (low exothermic properties) and better dynamic characteristics than polyurethane resins using toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI). . As the polyol component of the polyurethane resin, ester (adipate), caprolactone, carbonate, ether, and the like can be used. Of these, ester (adipate), caprolactone, and carbonate are better in bending fatigue resistance and other mechanical properties, while ether> carbonate> caprolactone in hydrolysis resistance. Although the order of the system> ester (adipate) system, the polyurethane resin using PPDI is higher in water resistance than the polyurethane resin using TDI, regardless of which polyol component is used. Degradable.

  FIG. 3 shows a mold for molding the support structure SS, and (a) is a front view and (b) is a longitudinal sectional view. The mold 10 has a cavity C corresponding to the support structure SS. Each of the cavities C1 to C5 corresponds to the inner annular portion 1, the intermediate annular portion 2, the outer annular portion 3, the inner coupling portion 4, and the outer coupling portion 5 of the support structure SS, respectively. Such a cavity C includes a cylindrical middle mold 11, a cylindrical outer mold 12, cross-sectional fan-shaped cores 13 and 14, and a disk-shaped upper mold 15 (not shown in FIG. 3A). And a disk-shaped lower mold 16. The middle die 11 is formed on the inner peripheral side of the inner annular portion 1, the outer die 12 is formed on the outer peripheral side of the outer annular portion 3, and the core 13 is formed between the outer peripheral side of the inner annular portion 1 and the intermediate annular portion 2. The inner peripheral side and the inner connecting part 4 are formed, and the core 14 is for forming the inner peripheral side of the outer annular part 3, the outer peripheral side of the intermediate annular part 2, and the outer connecting part 5. Moreover, the upper mold | type 15 and the lower mold | type 16 are for shape | molding the tire width direction both sides | surfaces of support structure SS. The upper mold 15 is provided with an injection port 15a. The middle mold 11, the outer mold 12, and the cores 13 and 14 can be fixed to the lower mold 16, and the upper mold 15 can be opened and closed with respect to the lower mold 16.

  The production method of the present invention is a production method capable of suitably producing the non-pneumatic tire T as described above, and a step of adjusting the raw material liquid of the thermosetting resin so that the liquid viscosity is 600 to 6000 mPa · s; And a step of stirring and adjusting the prepared thermosetting resin raw material liquid, and a step of injecting and curing the defoamed thermosetting resin raw material liquid into a mold.

  When the manufacturing process of the non-pneumatic tire T is started, the adjustment process of step S10 is first performed. In the adjusting step, the raw material liquid for the thermosetting resin is adjusted so that the liquid viscosity is 600 to 6000 mPa · s. By setting the liquid viscosity to 600 to 6000 mPa · s, it is difficult to chew the bubbles and the bubbles are easily removed in the stirring and defoaming step described later. In addition, the liquid viscosity of this invention is a liquid viscosity in 80 degreeC of the raw material liquid of a thermosetting resin.

  Next, the stirring / defoaming step of step S20 is performed. In the stirring and defoaming step, the raw material liquid of the thermosetting resin whose liquid viscosity is adjusted in the adjusting step of Step S10 is stirred and defoamed.

  In the stirring / defoaming step, it is preferable to stir the raw material liquid of the thermosetting resin using a rotation / revolution mixer. The reason why the rotation / revolution mixer is used is to stir the raw material liquid while suppressing the chewing of bubbles. In the case of only rotation, the raw material liquid can be stirred, but the bubbles are bitten simultaneously with the stirring. By revolving together with the rotation, the raw material liquid can be stirred while effectively removing bubbles.

  When the thermosetting resin raw material liquid is stirred using a rotation / revolution mixer, the rotation speed is preferably 700 rpm or more, the rotation speed is 400 rpm or more, and the stirring time is preferably 1 minute or more. Further, it is more preferable that the revolution speed is 1400 rpm or less, the rotation speed is 700 rpm or less, and the stirring time is 5 minutes or less. When the revolution speed is less than 700 rpm, the rotation speed is less than 400 rpm, or the stirring time is less than 1 minute, the bubbles cannot be sufficiently removed, and the raw liquid of the thermosetting resin is not sufficiently stirred, and after the curing Decreases in hardness. When the revolution speed exceeds 1400 rpm, the rotation speed exceeds 700 rpm, or the stirring time exceeds 5 minutes, a lot of bubbles are generated during stirring, voids increase, and durability deteriorates.

  Next, a casting process in step S30 is performed. In the casting process, the raw material liquid of the thermosetting resin defoamed in the stirring / defoaming process of step S20 is poured into the cavity C of the mold 10 from the injection port 15a. Examples of the raw material liquid for the thermosetting resin include those obtained by softening the above-described thermosetting resin at a high temperature, and liquid raw materials before reaction curing or before crosslinking.

  The raw material liquid of the thermosetting resin injected into the mold 10 is heated and cured, and the support structure SS of the non-pneumatic tire T is molded. Thereafter, if necessary, the belt layer 6 and the tread layer 7 are wound around and joined to the outer peripheral side of the removed support structure SS via an adhesive to manufacture the non-pneumatic tire T.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, the evaluation item in an Example etc. measured as follows.

(1) Durability Using an indoor drum testing machine equipped with a drum with a diameter of 500 mm, setting the test speed to 12 km / h, starting the tire load from 85% of the JIS standard, and increasing the load every specified time, Finally it was run at 140%. The mileage until failure occurred was measured. When the travel distance until the failure occurred was 200 km or less, it was “X”, when it exceeded 200 km and 1000 km or less, it was “Δ”, and when it exceeded 1000 km, it was “◯”.

(2) Number of voids About the manufactured non-pneumatic tire, the number of voids visible from the outside was counted per 10 cm ² . Voids with a diameter of 100 μm or more were counted.

(3) Resin hardness (Shore A hardness)
The hardness of the manufactured non-pneumatic tire was measured. Hardness affects durability.

Comparative Examples and Examples Liquid viscosity, rotation speed, revolution speed, and stirring time were varied as shown in Table 1 and Table 2, and Comparative Examples 1 and 2 and Examples 1 to 10 were used, respectively. The evaluation results are shown in Tables 1 and 2.

  The following can be understood from the results of Tables 1 and 2. In Comparative Example 1, since the liquid viscosity is low, a large amount of foam biting occurs, resulting in a large number of voids and poor durability. On the other hand, in Comparative Example 2, since the liquid viscosity is high, generation of voids is suppressed, but weld due to poor casting and hardness reduction due to poor stirring occur, resulting in poor durability.

  In Examples 1 to 10, generation of voids was suppressed and durability was improved as compared with Comparative Examples 1 and 2.

  In Example 1, generation of voids was suppressed and durability was improved as compared with Comparative Example 1.

  In Example 2, compared with Example 1, since the liquid viscosity was high, bubbles were not easily removed, and the number of voids slightly increased. As a result, the durability was lower than that in Example 1.

  Since Example 3 had a lower revolution speed than Example 4, the hardness was lowered and the durability was lowered.

  In Example 5, compared with Example 4, since the revolution speed was faster, the balance with the rotation speed was lost, and it became easier to chew bubbles when stirring and voids increased. As a result, durability was lowered.

  Since Example 6 had a lower rotation speed than Example 4, the hardness was low and the durability was lowered.

  Since Example 7 had a higher rotation speed than Example 4, it became easier to chew bubbles when stirring and voids increased. As a result, durability was lowered.

  In Example 8, compared with Example 9, the stirring time was short, so the hardness was low and the durability was lowered.

  In Example 10, as compared with Example 9, the stirring time was longer, so it was easier to chew bubbles when stirring and voids increased. As a result, durability was lowered.

DESCRIPTION OF SYMBOLS 1 Inner ring part 2 Middle ring part 3 Outer ring part 4 Inner connection part 5 Outer connection part 10 Mold C cavity SS Support structure T Non-pneumatic tire

Claims (3)

A method for producing a non-pneumatic tire composed of a thermosetting resin,
Adjusting the raw material liquid of the thermosetting resin so that the liquid viscosity is 600 to 6000 mPa · s;
A step of stirring and defoaming the adjusted raw material liquid of the thermosetting resin;
And a step of injecting and curing the defoamed raw material liquid of the thermosetting resin into a mold.   The method for producing a non-pneumatic tire according to claim 1, wherein in the step of stirring and defoaming the raw material liquid of the thermosetting resin, stirring is performed using a rotation / revolution mixer. In the step of stirring and defoaming the thermosetting resin raw material liquid, using a rotation / revolution mixer, the rotation speed is 700 rpm or more, the rotation speed is 400 rpm or more, and the stirring time is stirred for 1 minute or more. The method for producing a non-pneumatic tire according to claim 1.

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