JP2015166134A - Manufacturing method for sound absorption tyre - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tyre which can improve sound absorption performance.SOLUTION: A manufacturing method for a sound absorption tyre with a sound absorber bonded to the inner surface of the tyre comprises an adhesive applying process for applying a light-curable adhesive or a heat-curable adhesive to the inner surface of a tyre a light-curable adhesive or a heat-curable adhesive, an adhesive curing process for curing the light-curable adhesive or the heat-curable adhesive applied in the adhesive applying process with light or heat, and a sound absorber adhesion process for making the sound absorber adhere to the curable adhesive before, during, or after the adhesive curing process.

Description

  The present invention relates to a method for manufacturing a sound-absorbing tire in which a sound-absorbing body is bonded to an inner surface.

  There is known a tire in which a sound absorber is bonded to the inner surface of a tire for the purpose of reducing cavity resonance caused by the length of a circular pipe inside the tire. For example, Patent Document 1 proposes a tire in which a sound absorbing body (sound damping body) is fixed to the inner cavity surface of a tire via a double-sided adhesive tape.

JP 2007-112395 A

  Currently, there is a demand for tires with higher sound absorption performance. As a result of the inventor's earnest research, in the conventional tire described above, the double-sided adhesive tape is difficult to follow the inner surface shape of the tire, particularly at the side portion of the tire. Since the contact area with the body cannot be made sufficiently large, it has been found that the sound-absorbing body has poor adhesion to the inner surface of the tire and the sound-absorbing performance may not be fully exhibited.

  An object of the present invention is to provide a tire that can sufficiently improve the sound absorption performance.

The method for producing a sound-absorbing tire according to the present invention includes: applying a liquid photocurable adhesive or a thermosetting adhesive on the inner surface of the tire; and applying the light applied in the adhesive applying step. A curable pressure-sensitive adhesive or a thermosetting pressure-sensitive adhesive is cured with light or heat, and a sound absorber is attached to the curable pressure-sensitive adhesive before, during or after the pressure-sensitive adhesive curing step; A sound absorber adhering step.
According to this method for manufacturing a sound absorbing tire, the sound absorbing performance can be sufficiently improved.
Here, “applying a photocurable adhesive or a thermosetting adhesive” includes spraying a photocurable adhesive or a thermosetting adhesive.

Here, in the method for manufacturing a sound absorbing tire according to the present invention, it is preferable to perform the sound absorber adhering step after the pressure-sensitive adhesive curing step.
In this way, by performing the sound absorber adhering step in a state where the pressure-sensitive adhesive is cured and the adhesiveness is increased, the sound absorber adheres to the tire inner surface, and the sound absorption performance can be further improved.

In the method for producing a sound absorbing tire according to the present invention, it is preferable that the sound absorbing body is composed of short fibers.
In this case, the sound absorption performance can be further improved.

  According to the sound absorbing tire manufacturing method of the present invention, the sound absorbing performance can be sufficiently improved.

It is a tire width direction sectional view showing a tire manufactured by one embodiment of a manufacturing method of a sound absorption tire of this invention. It is a mimetic diagram shown in the state where the tread part neighborhood of the tire was expanded for explaining one embodiment of the manufacturing method of the sound-absorbing tire of this invention. The carcass and the like inside the tire are not shown. It is a figure which shows the sound pressure level of the cavity resonance sound of a comparative example tire and an Example tire.

FIG. 1 illustrates a tire 1 manufactured by one embodiment of a method for manufacturing a sound absorbing tire according to the present invention.
The tire 1 is disposed on the outer peripheral side of the carcass 2 formed by one or more carcass plies and the crown area of the carcass 2 by a cord disposed in the radial direction across the pair of bead portions 7. It is composed of a belt ply made of a metal cord extending incline with respect to the tire circumferential direction. Here, two layers of the inclined belt layer 3 and the outer circumferential side of the inclined belt layer 3 are arranged and directed toward the tire circumferential direction. Here, one belt reinforcing layer 4, a tread 5 which is disposed on the outer peripheral side of the belt reinforcing layer 4 to form a tread ground surface, and a bead portion 7 are formed of a reinforcing layer made of an organic fiber cord extending in the direction. And a pair of sidewall portions 6 extending outward in the tire radial direction.

As shown in FIG. 1, on the inner surface 8 of the tire, a large number of short fibers 11 constituting the sound absorbing body are light-curing pressure-sensitive adhesive or thermosetting pressure-sensitive adhesive (hereinafter collectively referred to as “curing-type pressure-sensitive adhesive”). Is also bonded over the entire circumference of the tire in the entire range in the tire width direction excluding the vicinity of the bead portion 7. However, this range is not limited to the above, and can be set as appropriate according to the purpose.
The short fiber 11 can absorb the cavity resonance sound generated in the tire 1.

From here, an embodiment of a method for producing a sound-absorbing tire according to the present invention will be described.
First, a raw tire is vulcanized with a vulcanization mold to produce a vulcanized tire 1 as shown in FIG. Here, a release material such as silicone may be applied to the inner and outer surfaces of the tire before vulcanization so that the vulcanized tire can be easily removed from the mold. In this case, from the viewpoint of facilitating application of the curable pressure sensitive adhesive described later, it is preferable to wipe off the release material before applying the curable pressure sensitive adhesive.

Next, as a pressure-sensitive adhesive application step, as shown in FIG. 2 (b), on the inner surface 8 of the tire 1, the region where the short fibers 11 are bonded, that is, the entire range in the tire width direction excluding the bead portion 7, A liquid photocurable adhesive or thermosetting adhesive 12 is applied over the entire circumference of the tire. However, this range is not limited to the above, and can be set as appropriate according to the purpose. Application can be performed with a brush, spray, slit nozzle coater, slot die coater, or the like.
Thus, by making the curable pressure-sensitive adhesive 12 applied on the inner surface 8 of the tire 1 into a liquid state, the wettability of the pressure-sensitive adhesive 12 is increased, and the pressure-sensitive adhesive 12 is spread and impregnated throughout the tire inner surface. The contact area between the tire inner surface and the pressure-sensitive adhesive can be increased to increase the adhesive force. As will be described later, the sound-absorbing performance can be improved by increasing the adhesion of the sound absorber to the tire inner surface.

Here, when the sound absorbing body is bonded using the double-sided pressure-sensitive adhesive tape, an end portion may be formed at a position where the double-sided pressure-sensitive adhesive tape is started to be applied or a position where the double-sided adhesive tape is finished. In such a case, the double-sided pressure-sensitive adhesive tape may be peeled off from the end portion during running.
On the other hand, in order to eliminate the end of the double-sided pressure-sensitive adhesive tape, if the double-sided pressure-sensitive adhesive tape is pasted so that the sticking start position and the sticking end position overlap, the thickness of the double-sided pressure-sensitive adhesive tape cannot be made uniform, and the tire There was a risk of affecting the uniformity.
On the other hand, according to the present invention using a liquid curable pressure-sensitive adhesive, it is possible to eliminate the end portion as a starting point of peeling and make the thickness of the curable pressure-sensitive adhesive uniform.

  Furthermore, when a double-sided pressure-sensitive adhesive tape is used, air may be mixed between the tape and the tire inner surface. On the other hand, in this invention, air does not mix between a liquid adhesive and a tire inner surface. As a result, according to the present invention, separation between the tire inner surface and the pressure-sensitive adhesive can be effectively suppressed, and as a result, separation between the tire inner surface and the sound absorber can also be effectively suppressed.

Then, as the adhesive curing step, the curable adhesive applied as described above is cured with light or heat. In the example shown in FIG. 2C, the curable pressure-sensitive adhesive 12 contains a photo radical generator as a radical generator and is cured by irradiation with light 101. As the light 101, electromagnetic waves such as ultraviolet rays, visible rays, infrared rays, and X-rays, and particle beams such as α rays, γ rays, and electron beams can be used. From the viewpoint of improving the adhesive strength and reducing the cost, the irradiation of the ultraviolet ray 101 is performed by using an ultraviolet lamp with an ultraviolet ray centered at a wavelength of 365 nm at an irradiation intensity of 50 to 300 mW / cm ² for 1.5 to 2 seconds (75 to (Integrated light amount of 600 mJ / cm ² ) is preferable.
On the other hand, the curable pressure-sensitive adhesive 12 can be cured by heating by containing a thermal radical generator as a radical generator. In this case, it is preferable to heat at 100 to 130 ° C. for 5 to 20 minutes from the viewpoint of efficiently generating radicals in the thermal radical generator.
By this step, the pressure-sensitive adhesive that has been liquid can be made viscous and pasty. Moreover, the adhesive force after the said process can be 20 N / 25mm or more, for example.

Here, it is preferable to use a photocurable pressure-sensitive adhesive as the curable pressure-sensitive adhesive. Thereby, after apply | coating an adhesive, an adhesive can be hardened immediately, As a result, while being able to prevent an adhesive from dripping, the thickness of a curable adhesive can be made more uniform.
Note that this step may include a step of leaving the tire at room temperature before and after applying light or heat to the curable adhesive.

In this embodiment, after the above-described pressure-sensitive adhesive curing step, as a sound absorber attaching step, as shown in FIG. 2D, a sound absorber (short fibers 11 in this embodiment) is attached to the curable pressure-sensitive adhesive 12 to absorb the sound. The body is adhered to the curable adhesive 12.
Here, the sound absorbing performance can be further improved by configuring the sound absorbing body with short fibers as in this embodiment. In general, short fibers have good compatibility with the above liquid curable pressure-sensitive adhesive, so that sound absorption performance can be improved from this point.
The short fibers 11 can be attached by various methods, for example, electrostatic flocking can be used. Electrostatic flocking is a technology in which short fibers are charged and the short fibers are vertically planted on the surface to be adhered by electrostatic force. By using this technology, a large number of short fibers are put on the inner surface of the tire. It is easy to stand up, and the short fibers can be reliably planted on the curved inner surface of the tire.
Here, the sound absorber attaching step can be performed before, during or after the pressure-sensitive adhesive curing step. When the sound absorber adhering step is performed before the adhesive curing step, for example, after applying the curable pressure-sensitive adhesive, it is allowed to stand at room temperature, and then the sound absorber is attached to the inner surface of the tire and light or heat is applied. In addition, the curable adhesive is cured.
However, as in the above-described embodiment, it is preferable to perform the sound absorber attaching step after the pressure-sensitive adhesive curing step. In this way, by performing the sound absorber adhering step in a state where the pressure-sensitive adhesive is cured and the adhesive property is increased, the adhesive property of the pressure-sensitive adhesive is expressed to the maximum, and the sound absorber adheres to the tire inner surface, Sound absorption performance can be further improved.

Generally, the curable adhesive 12 contains a curing agent. For this reason, the curable pressure-sensitive adhesive 12 is allowed to stand at room temperature, for example, and after a certain curing period (for example, 1 hour to 4 days), crosslinks are generated and become harder.
Therefore, in this embodiment, the tire is allowed to stand at room temperature, for example, for 1 hour to 4 days as a curing process after the sound absorber attaching process. As described above, in the sound absorber adhering step, the curable adhesive can be easily penetrated into the sound absorber. Thereafter, through the curing process, the curable pressure-sensitive adhesive 12 is tightened, the sound absorber becomes difficult to be detached, and a greater resistance against peeling can be exhibited. As a result, the sound absorption performance can be maintained over a long period.
In addition, you may further use metals, such as an amine and tin, as a catalyst. By using these, it becomes possible to control the time of the curing process.

In addition, in this invention, an acrylic adhesive can be used as a photocurable adhesive or a thermosetting adhesive, for example. The acrylic pressure-sensitive adhesive material is a general term for pressure-sensitive adhesives made from monomers (monomers) called acrylic acid esters and methacrylic acid esters. In addition, for example, epoxy-based, silicone-based, and urethane-based pressure-sensitive adhesives can be used.
And tackifying resin (tackifier), such as terpene resin, can also be mix | blended with said curable adhesive.
Furthermore, as a curing agent that can be included in the curable pressure-sensitive adhesive, for example, an isocyanate compound and an epoxy compound can be used.

As the sound absorber, in addition to short fibers, sponge, hard urethane foam, soft urethane foam, EPDM foam, polyethylene foam, and the like can be used.
As the short fibers, organic synthetic fibers, inorganic fibers, regenerated fibers, natural fibers, and the like can be used.
Examples of organic synthetic fibers include polyolefins such as polyethylene, polypropylene, and polybutylene, aliphatic polyamides, aromatic polyamides, polyethylene terephthalate, polyethylene naphthalate, polyethylene succinate, polyesters such as polymethyl methacrylate, and syndiotactic-1, 2. -Polybutadiene acrylonitrile butadiene styrene copolymer, polystyrene, and copolymers thereof can be used. Since these organic synthetic fibers are generally inexpensive, chemically stable, and have good compatibility with urethane adhesives, they are suitable for use in the method for producing a sound absorbing tire according to the present invention.
Examples of inorganic fibers include carbon fibers and glass fibers, examples of regenerated fibers include rayon and cupra, and examples of natural fibers include cotton, silk, and wool.

The short fibers are preferably short fibers having an average diameter D of 1 μm to 500 μm and an average length L of 0.5 mm to 10 mm. Further, the ratio (L / D) between the average length L and the average diameter D of the short fibers is preferably 5 or more and 2000 or less. That is, when L is less than 0.5 mm or L / D is less than 5, the effect of reducing the cavity resonance sound may be reduced. When L exceeds 10 mm or L / D exceeds 2000, , The short fibers are entangled with each other to form lumps, and the short fibers may not sufficiently exhibit the sound absorbing effect. If D is less than 1 μm, yarn breakage frequently occurs in the short fiber manufacturing process, and productivity may decrease. On the other hand, when D exceeds 500 μm, rolling resistance increases due to an increase in the weight of the tire, and the fuel consumption of the vehicle equipped with the tire may be deteriorated.
Further, from the viewpoint of enhancing the sound absorption effect, it is preferable to provide the short fibers with an average density of 100 or more per square centimeter in the portion where the short fibers 11 of the inner surface 8 of the tire are provided.

  Example tires and comparative tires were prototyped under the specifications shown below, and the cavity resonance sound was evaluated for each prototype tire, which will be described below.

  Example tire 1 is coated with a liquid acrylic photo-curing adhesive on the inner surface of a pneumatic tire having a size of 205 / 55R16 over the entire circumference of the tire in the tire width direction excluding the bead portion. Then, after curing the photocurable pressure-sensitive adhesive by ultraviolet irradiation, about 20 g of nylon short fibers having a thickness of 15 denier (φ45 μm) and a length of 2.5 mm were put into the tire by electrostatic flocking. It was made to adhere to the surface.

  Example tire 2 is that a liquid acrylic thermosetting adhesive is applied instead of a liquid acrylic photocurable adhesive, and then the photocurable adhesive is cured by heating. Except for this, the tire was manufactured in the same manner as in Example tire 1.

  Example tire 3 is an example tire except that nylon short fibers are attached to the inner surface of the tire using electrostatic flocking before the photocurable adhesive is cured by irradiation with ultraviolet rays. 1 in the same manner.

  Example tire 4 was carried out except that the nylon short fibers were adhered to the tire inner surface using electrostatic flocking while the photocurable adhesive was cured by irradiation with ultraviolet rays. The tire was manufactured in the same manner as Example Tire 1.

  Example tire 5 is not a nylon short fiber, but a sponge having a thickness of 2.5 mm, which is attached to the entire tire width direction on the inner surface of the tire except for the bead over the entire circumference of the tire. The tire was manufactured in the same manner as in Example tire 1.

  On the other hand, the comparative tire 1 is not processed on the inner surface of a pneumatic tire having a size of 205 / 55R16.

<Cavity resonance sound evaluation>
The above-described Example tire and Comparative Example tire were mounted on an applicable rim (6.5JJ-16) defined in JATMA standard and mounted on a 2000 cc class passenger vehicle. A microphone in which the above vehicle is driven at 50 km / hr under conditions of internal pressure of 220 kPa and one passenger on an asphalt-paved rough road surface, and a cavity resonance sound of a pneumatic tire is installed at the driver's ear And the sound pressure level (dB (A)) was evaluated. The evaluation results are shown in FIG. FIG. 3 shows a comparison between the comparative example tire 1 and the example tire 1.

  The sound absorption effect shown in Table 1 shows the reduction amount (dB (A)) of the sound pressure level at the peak near 235 Hz where the difference in the in-vehicle noise appears most prominently. It shows that the effect of reducing a cavity resonance sound is so high that the reduction amount of a sound pressure level is large.

  From Table 1, it became clear that the Example tires 1 to 5 have a higher sound absorbing effect than the comparative example tire 1.

1: pneumatic tire, 2: carcass, 3: inclined belt layer, 4: belt reinforcing layer,
5: tread, 6: sidewall portion, 7: bead portion, 8: inner surface of tire,
11: short fiber (sound absorber), 12: photo-curing adhesive or thermosetting adhesive,
101: UV

Claims (3)

A method for producing a sound-absorbing tire in which a sound-absorbing body is bonded to the inner surface of the tire,
Applying a liquid photocurable adhesive or thermosetting adhesive on the inner surface of the tire, an adhesive application step,
An adhesive curing step of curing the photocurable adhesive or thermosetting adhesive applied in the adhesive application step with light or heat;
Before, during or after the pressure-sensitive adhesive curing step, a sound absorber is attached to the curable pressure-sensitive adhesive, and
A method for producing a sound-absorbing tire, comprising:   The method for manufacturing a sound absorbing tire according to claim 1, wherein the sound absorber adhering step is performed after the pressure sensitive adhesive curing step. The method for manufacturing a sound-absorbing tire according to claim 1 or 2, wherein the sound-absorbing body is composed of short fibers.

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