JP4567423B2 - Tire silencer - Google Patents

Description

The present invention relates to a tire noise control device that reduces road noise during traveling by being mounted in a tire lumen.

  One of the tire noises is so-called road noise that produces a “go” sound in the frequency range of 50 to 400 Hz when traveling on the road surface, and the main cause is resonance vibration of air that occurs in the tire lumen ( Cavity resonance) is known. Therefore, in recent years, a long band-shaped sound-damping tool made of sponge material and extending in the tire circumferential direction has been placed in the tire lumen, and cavity resonance has been achieved by relaxing and absorbing the resonance sound energy generated in the tire lumen. A technique for suppressing road noise and reducing road noise has been proposed (see, for example, Patent Document 1).

JP 2003-063208 A

  However, since the sponge material has high water absorption, there is a risk that the sponge material may get wet by rainwater or the like when storing the tire or assembling the rim. When the rim is assembled in this water absorption state, the absorbed water has an adverse effect on the weight balance, causing tire vibration, and the absorbed water penetrates into the rubber of the tire and induces internal damage. Invite. Therefore, when assembling the rim, it is necessary to remove water sufficiently. However, it is not easy to instantly dry the sponge material once wet, and the handling is troublesome.

  Therefore, the present invention is based on the use of a water-repellent polyurethane foam in which a polyol is specified and a water-repellent agent is blended as a sponge material, and can exhibit excellent water-repellent performance and has been exposed to water for a long time. Even in this case, the tire can be quickly dried by wiping, etc. without absorbing water, improving handleability and reliably preventing problems such as tire vibration and tire internal damage caused by water absorption. The purpose is to provide sound equipment.

In order to achieve the above object, the invention according to claim 1 of the present application is a tire sound control device mounted in a tire lumen formed by a rim and a pneumatic tire mounted on the rim,
A base material made of a sponge material having a specific gravity of 0.005 to 0.060, fixed to the inner rim surface or the inner luminal surface of the tire and extending in the tire circumferential direction;
The sponge material comprises a water-repellent polyurethane foam obtained by foam-curing a mixed composition containing a polyisocyanate, a polyol, a water repellent and a foaming agent, and the polyol is a polyester polyol and a polyester / polyether copolymer. Mixed with polyol,
Moreover, the polyol is composed of 3 to 60% by weight of polyester polyol and 97 to 40% by weight of polyester / polyether copolymer polyol, and the water repellent is 25 to 80% by weight based on 100 parts by weight of polyol. with parts being formulated,
The water repellent is an ester, and is characterized in that it is a conjugate of a monoalcohol having 14 to 36 carbon atoms and an aliphatic dicarboxylic acid or alicyclic dicarboxylic acid having 14 to 36 carbon atoms .

  The invention of claim 2 is characterized in that the foaming agent is water, and the blending amount thereof is 2.5 to 6.0 parts by weight with respect to 100 parts by weight of polyol.

In the invention of claim 3, the polyol comprises 15 to 35% by weight of polyester polyol and 85 to 65% by weight of polyester / polyether copolymer polyol, and the water repellent comprises 100 parts by weight of polyol. 30 to 50 parts by weight is blended with respect to.

  Since the present invention is configured as described above, it can exhibit excellent water repellency, can be quickly dried by wiping, etc. without absorbing water even when exposed to water for a long time, The handleability can be improved and problems such as tire vibration and tire internal damage caused by water absorption can be reliably prevented.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a meridional sectional view of an assembly of a pneumatic tire and a rim (hereinafter sometimes simply referred to as an “assembly”) in which the tire sound damping device of the present invention is mounted in the tire lumen, and FIG. The circumferential direction schematic sectional drawing along the solid tire equator surface is shown.

  In FIG. 1, the assembly 1 includes a pneumatic tire 2 (sometimes simply referred to as “tire 2”) and a rim 3, and the tire 2 and the rim 3 are mounted by attaching the tire 2 to the rim 3. And the tire lumen 4 is formed.

  The rim 3 has a well-known structure including an annular rim body 3a on which the tire 2 is mounted and a disk 3b that supports the rim body 3a and is fixed to the axle. In this example, the standard such as JATMA is used. The case where the regular rim which prescribes | regulates is employ | adopted is illustrated. The tire 2 is a radial tire for passenger cars, for example, which is assembled with the bead portion 2a in close contact with the flange of the rim body 3a. The cavity surface S1 is provided with a tubeless structure formed of an inner liner rubber made of low air permeable rubber. Thereby, the tire 2 forms an airtight tire lumen 4 with the rim body 3a.

  In the tire lumen 4 of the assembly 1, there is a base 6 made of a sponge material that is fixed to the tire-side lumen surface S1 or the rim-side lumen surface S2 and extends in the tire circumferential direction. A sound control tool 5 is attached. In this example, the case where the base body 6 has a long belt shape and both ends in the tire circumferential direction are spaced apart is illustrated.

  Here, as the sponge material, a polyurethane foam having a specific gravity of 0.005 to 0.060, preferably 0.010 to 0.045 obtained by foaming a polyurethane resin is used. Since such a sponge material has high vibration proofing and sound absorbing properties, the resonance sound energy generated in the tire lumen 4 can be effectively relaxed and absorbed. As a result, cavity resonance can be suppressed and road noise can be reduced. Further, the sponge material is easily deformed such as contraction and bending, so that the rim assembly property is not impaired, and the specific gravity is very small, so that the adverse effect on the tire weight balance can be kept low.

  As in the case described in Patent Document 1, it is preferable that the sound control tool 5 has a volume V2 set to 0.4 to 20% of the total volume V1 of the tire lumen 4, and is less than 0.4%. Then, the effect of suppressing cavity resonance is not sufficiently exhibited. On the other hand, if the ratio V2 / V1 exceeds 20%, the cavity resonance suppression effect will reach its peak, and an unnecessary increase in weight and cost will be caused.

  Further, in the above-described sound control device 5, the sound control device 5 itself is destroyed due to an excessive force acting on the sound control device 5 or a collision with a tire or a rim due to various accelerations received during high speed running. In order to suppress this, as described above, the sound control tool 5 is fixed to the tire cavity surface. In particular, in this example, a case where the bottom surface 5a of the sound control tool 5 is attached to the tread region J of the tire-side lumen surface S1 is illustrated. This is because the centrifugal force during high-speed traveling is directed outward in the radial direction, and by fixing the tread region J to the tread region J, the sound control tool 5 can be pressed against the lumen surface S1 by the centrifugal force, and the movement is effective. This is because it can be restrained. From this point of view, it is preferable to fix the noise control tool 5 at the center of the tread region J so that the width center line thereof is along the tire equator C. At this time, it is preferable that the noise damper 5 has a line-symmetric shape with the tire equator C as the center in the tire meridian cross section as in this example. This is because, in the case of a non-axisymmetric shape, the lateral rigidity is different between the left and right, so that it tends to fall down to the low rigidity side. The “tread region J” means a region between radial lines passing through both outer ends of the belt layer 7.

  The cross-sectional shape of the sound damper 5 is not particularly limited, and various shapes such as a rectangular shape, a trapezoidal shape, a triangular shape, a warhead shape, and a semicircular shape can be employed.

  However, as shown in FIGS. 5A and 5B, a flat and substantially trapezoidal shape having a greatly inclined side surface 5c is used as shown in FIGS. Is preferred. In detail, while setting the height T1 of the noise control tool 5 as low as 1.0 to 4.5 cm, both side surfaces of the sound control tool 5 extending from the both end portions of the bottom surface 5a to the tip surface 5b forming the height T1. 5c is positioned at least on the tip surface 5b side and has an angle α of 30 to 75 °, preferably 30 to 70 °, more preferably 30 to 60 ° with respect to the bottom surface 5a. An inclined surface portion 5c1 that is inclined to reduce the width is provided. By providing the inclined surface portion 5c1, when the bead portion 2a of the tire 2 is removed from the rim 3, a portion that easily interferes with the tip portion of the tire lever that tilts in the tire lumen 4 is removed. Therefore, damage to the sound control tool 5 due to contact with the tire lever can be effectively prevented. Even in the case of contact, the inclined surface portion 5c1 approximates the tangential direction of the arc-shaped locus drawn by the tip portion of the tire lever, so that the tip portion of the tire lever does not easily bite into the sound control tool 5, and The frictional force between the tire lever and the inclined surface portion 5c1 is reduced. Therefore, it is possible to effectively prevent the noise control device 5 from being peeled off from the tire 2 and the sound control device 5 itself from being damaged.

  The side surface 5c can include a right-angled surface 5c2 having a small height (for example, 75% or less of the height T1) rising substantially vertically from the bottom surface 5a. However, even if the side surface 5c is formed only by the inclined surface portion 5c1. good. Further, the inclined surface portion 5c1 can be formed as a flat surface as shown in FIG. 5A or a curved surface such as an arc surface curved as a concave shape as shown in FIG. 5B. Further, as shown in FIG. 5A, a concave groove 10 can be formed in the distal end surface 5b. In such a case, the heat radiation effect can be enhanced by increasing the surface area due to the concave groove 10, and the thick portion 11 for storing heat can be divided into left and right. As a result, it is possible to reduce the temperature rise of the tire caused by the sound damper 5 that easily stores heat, and to improve the high-speed durability of the tire.

  As the attachment of the sound damper 5, for example, a synthetic rubber liquid adhesive such as a solution type in which a synthetic rubber is dissolved in an organic solvent and a latex type in which the rubber is dispersed in water, or a double-sided adhesive tape is preferably used. Can be adopted. In particular, the double-sided pressure-sensitive adhesive tape can be preferably used because it is easy to handle and has excellent adhesion work efficiency. In this example, the sound control tool 5 has a double-sided adhesive tape 8 (shown in FIG. 3) attached in advance to its bottom surface 5c.

  Further, as in this example, when the sound control tool 5 is attached with a gap between both ends in the tire circumferential direction, stress is applied to the tire circumferential outer end e and the vicinity of the adhesive surface due to acceleration during running. Tend to concentrate and crack from there. Therefore, in this example, as shown in a side view of the noise damper 5 before sticking in FIG. 3, the outer end e in the tire circumferential direction is at an acute angle θ with the outer end surface eS having an acute angle with respect to the bottom surface 5c. It is formed by intersecting inclined surface portions 5A. Thereby, the height and mass at the outer end e can be reduced, the stress acting on the adhesive surface itself can be reduced, and the occurrence of cracks can be suppressed. For this purpose, the angle θ is preferably suppressed to 70 ° or less, and if it exceeds 70 °, the effect of suppressing the occurrence of cracks is insufficient. When the angle θ is less than 15 °, the amount of sponge in the inclined surface portion 5A becomes too small, so that the road noise reduction effect at this portion 5A becomes too small, and the road noise reduction effect as a whole becomes insufficient. .

  The outer end surface eS is preferably a flat surface as in this example from the viewpoint of productivity. However, as shown in FIGS. 4A and 4B, for example, a convex arc shape or a curved arc surface shape, In this case, the angle θ formed by the straight line X connecting the upper and lower ends of the curved surface is set as the range, and the maximum separation distance h of the curved surface from the straight line X is set as the range θ. It is good to regulate to 10 mm or less.

  In addition, as the noise suppression tool 5, the annular body in which the tire circumferential direction both ends continue mutually may be sufficient. At this time, when the diameter of the outer peripheral surface of the noise control tool 5 is equal to or larger than the diameter of the inner cavity surface S1 in a free state where it is not mounted in the tire lumen 4, the diameter of the inner peripheral surface of the noise control tool 5 is When the diameter is equal to or smaller than the diameter of the lumen surface S2, it can be easily fixed to the lumen surfaces S1 and S2 without using an adhesive.

  Next, since sponge materials usually have high water absorption properties, they absorb rainwater when storing tires or assembling rims, causing weight balance to be lost and causing tire vibrations, and improving the durability of sponge materials themselves. There is a possibility that various problems such as reduction or water absorption may permeate into the rubber of the tire and induce internal damage.

  Therefore, in this embodiment, as the sponge material, a water-repellent polyurethane foam obtained by foam-curing a mixed composition containing polyisocyanate, polyol, water repellent, and foaming agent is used. As the polyol, polyester polyol and polyester are used. -Polyether copolymer polyol is mixed. Thereby, it is possible to exhibit excellent water repellency while sufficiently ensuring the strength and road noise reduction effect necessary for the sound control device 5, and prevent various problems such as tire vibration and tire internal damage caused by the water absorption. It becomes possible.

  As is well known, a polyurethane foam is formed by foaming with a foaming agent when a polyisocyanate and a polyol react to form a urethane bond to form a crosslinked polyurethane.

  At this time, water is used as a foaming agent in this example. Water can react with the polyisocyanate in the mixed composition to generate carbon dioxide, thereby foaming the polyurethane crosslinked product. Normally, foaming agents such as methylene chloride (methylene chloride), pentane, etc., which have a low boiling point and are vaporized by the heat of reaction at the time of urethane bonding, are used. It causes unevenness in water-repellent performance such as non-uniform dispersion of the agent, and makes it difficult to obtain a high-quality foam having uniform cell diameter and cell density. Therefore, in this example, only water whose foaming is easily controlled is used as the foaming agent.

  The amount of water is preferably in the range of 2.5 to 6.0 parts by weight with respect to 100 parts by weight of the polyol. If it is less than 2.5 parts by weight, foaming becomes insufficient, and it is difficult to set the specific gravity of the sponge material to be in the above range, and if it exceeds 6.0 parts by weight, it is too foamed and the sponge material is hard. It tends to impair the sheath tear strength. In order to obtain sufficient durability, the sponge material preferably has a hardness of 30 N or more and a tear strength of 10 N / cm or more. However, even if the hardness exceeds 150 N, the elasticity tends to decrease and the durability tends to decrease. On the other hand, making the tear strength greater than 10 N / cm is an excessive quality, and disadvantages are caused in terms of cost and productivity. The “hardness” of the sponge material is measured in accordance with Method A (Section 6.3) of the “Hardness” measurement method in Section 6 defined in “Flexible Urethane Foam Test Method” of JIS K6400. It is the value. The “tear strength” is a value measured with respect to a No. 1 type test piece in accordance with the measurement method of “tear strength” in paragraph 11.

  Examples of the “polyisocyanate” include aromatic systems such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric MDI, naphthalene diisocyanate, paraphenylene diisocyanate, xylene diisocyanate (XDI), tetramethylxylene diisocyanate, and dimethyldiphenyl diisocyanate. Polyisocyanates such as polyisocyanate, hexamethylene diisocyanate, hydrogenated MDI, isophorone diisocyanate, lysine diisocyanate, hydrogenated XDI, cyclohexyl diisocyanate, and other aliphatic polyisocyanates, and modified products thereof can be used. Of these, TDI, MDI and their modified products are particularly suitable.

  In the present embodiment, a polyester polyol and a polyester / polyether copolymer polyol are mixed as the “polyol”. This is because by including the polyester / polyether copolymer polyol, the hydrolysis resistance can be enhanced while sufficiently securing the strength required for the noise control device 5. Further, by including the polyester polyol, the dispersibility of the water repellent can be improved, the viscosity of the mixed composition can be easily adjusted, and a foam having a low density (low specific gravity) can be obtained.

  However, if the proportion of the polyester polyol is too small, the compatibility between the water repellent and the polyester / polyether copolymer polyol is deteriorated, resulting in poor stirring, and a good foam in which the water repellent is uniformly dispersed is obtained. Disappear. On the other hand, if the proportion of the polyester polyol is too large, the ether chain is not contained in the polyurethane crosslinked body, so that the strength and hydrolysis resistance of the foam tend to be impaired. Therefore, the proportion of the polyester polyol is preferably 3 to 60% by weight, and the polyester / polyether copolymer polyol is preferably the remaining 97 to 40% by weight.

  At this time, the blending amount of the water repellent is preferably in the range of 25 to 80 parts by weight with respect to 100 parts by weight of the polyol. If the blending amount of the water repellent is less than 25 parts by weight, the water repellent performance is insufficient. Conversely, if it exceeds 80 parts by weight, the water repellent also acts as a plasticizer, making it difficult to form a foam. Become.

  In order to improve the strength, hydrolysis resistance, water repellency, and moldability in a well-balanced manner, the proportion of the polyester polyol in the total polyol is 15 to 35% by weight, and the polyester / polyether copolymer polyol The balance is preferably 85 to 65% by weight, and the amount of water repellent added to 100 parts by weight of polyol is preferably 30 to 50 parts by weight.

  Here, as the “polyester polyol”, for example, ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 2,5-hexanediol, 3-methyl-1,5- Low molecular polyols such as pentanediol, neopentyl glycol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, diglycerin, sorbitol, sucrose, succinic acid, adipic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid Lactones such as ε-caprolactone ring-opening polymer and β-methyl-δ-valerolactone ring-opening polymer other than those obtained by condensation with carboxylic acids such as acid, succinic anhydride, maleic anhydride and phthalic anhydride Based polyols and the like.

  As the “polyester / polyether copolymer polyol”, known ones can be used. For example, esterification reaction or transesterification reaction using aliphatic dicarboxylic acid or its ester-forming derivative and low molecular diol, and further polycondensation reaction, or transesterification of polyester polyol and polytetramethylene glycol The thing obtained by making it react can be mentioned. In the present invention, the use of the polyester / polyether copolymer polyol increases the strength of the foam, improves the hydrolysis resistance, and exhibits good water repellency.

  As the “water repellent”, an ester which is a conjugate of a monoalcohol having 14 to 36 carbon atoms and an aliphatic dicarboxylic acid or alicyclic dicarboxylic acid having 14 to 36 carbon atoms can be preferably used. If the number of carbon atoms is 14 or more, the hydrophobicity of the long-chain alkyl group can effectively act on the water repellency of the foam. If the number of carbon atoms is too large, the carbon number tends to be solid at room temperature or low temperature and is difficult to handle. Therefore, the upper limit of the carbon number is preferably 36 or less.

As such esters, for example,
(A) isostearyl stearate,
(B) oleyl stearate,
(C) stearyl oleate,
(D) Dimer acid dioleyl,
(E) distearyl dimer acid,
(F) a diester of a dimer acid and a mixture of higher alcohols having 32 to 36 carbon atoms,
Etc.

  In addition, the catalyst normally used for formation of a polyurethane foam and a foam stabilizer can be added to the said mixed composition similarly to the past.

  The water-repellent polyurethane foam obtained by foaming and curing such a mixed composition can sufficiently secure the mechanical strength necessary for the sound control device 5 and can improve hydrolysis resistance and water resistance. As a result of containing a water repellent and its dispersibility being improved more uniformly, excellent water repellency can be exhibited, water absorption of the sponge material can be suppressed, and various factors such as tire vibration and tire internal damage caused by the water absorption. Problems can be prevented. In addition, a sponge material having a lower density (low specific gravity) can be obtained while ensuring such characteristics, and a high road noise reduction effect can be achieved.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  A sound control tool for a deep rim with a rim size of 15 × 6 was prototyped according to the specifications shown in Table 1 and tested for its physical properties (hardness, tensile strength, elongation, water repellency) and productivity when forming a sponge material. . In addition, a water absorption test was performed in a state where the above-mentioned sound control device was mounted on a tire (195 / 65R15), and road noise performance in a non-water absorption state of the sound control device was evaluated by an actual vehicle test.

In addition, each of the sound control devices of Examples 1 to 5, Tables 1 and 2, and Comparative Examples 1 to 5 shown in Table 1 are the same in shape and size except for the material of the sponge material. (3.0 cm), a width (7.0 cm), a length (185 cm) of a rectangular cross section, and a long belt-shaped body having both end portions inclined surface portions 5A having an angle θ (= 45 °) are used. At the same time, it was adhered to the tire-side lumen surface S1 (tread region J) using a double-sided adhesive tape (5000NS manufactured by Nitto Denko Corporation). In each example, the volume V2 of the sound control tool is (3822 cm ³ ), and the ratio V2 / V1 to the total volume V1 (30500 cm ³ ) of the tire lumen is 12.5%.

  Conventional Examples 1 and 2 use a conventional ether-based polyurethane foam (product number E16, Maruzumi Co., Ltd.) that does not contain a water repellent. In Conventional Example 2, the surface of the sound control device is a waterproof sheet ( In this example, it is covered with a polyethylene film).

  The third embodiment is different from the third embodiment only in the cross-sectional shape, and prototypes the sound control devices of the sixth and seventh embodiments in which the material, length, volume V2 and the like of the sponge material are substantially the same. The sound body's “damage to sound” was additionally tested together with Example 3, and the results are shown in Table 2. Example 6 has a cross-sectional shape shown in FIG. 5A, and Example 7 has a cross-sectional shape shown in FIG. The dimensions are shown in the figure.

(1) hardness, tear strength, elongation;
“Hardness” is measured in accordance with Method A (Section 6.3) of the “Hardness” measurement method specified in Section 6 of “Testing method for flexible urethane foam” of JIS K6400. In accordance with the measurement method of “tensile strength and elongation” in paragraph 10, the measurement was performed on a No. 1 dumbbell-shaped test piece, and “tear strength” is the “tear strength” in paragraph 11. This is a value measured with respect to a No. 1 type test piece in accordance with the measurement method.

(2) water repellency;
As shown in FIG. 6, a test piece k of sponge material of 300 mm (length) x 70 mm (width) x 30 mm (height) was submerged in a water tank with a water depth of 150 mm, and the weight increase after being left for 24 hours was measured. The initial weight (corresponding to the dry weight of the test piece k) was compared.
When the increased weight was less than 100% of the initial weight ---, and when it was 100% or more --- x.
Reference numeral n in the figure is a pressing plate made of punched metal (hole diameter 5 mm) bent in a U-shape, and the test piece k is submerged in water so that no load is applied to the test piece k. Reference numeral p denotes weights (about 500 g / piece) arranged at the four corners of the pressing plate n, and prevents the pressing plate n from being lifted by buoyancy.

(3) Productivity when forming sponge material;
The presence / absence of various problems that occur in the production process such as the stirring process of the mixed composition and the foam molding process when the sponge material is molded (the contents in the case of being present) is displayed.

(4) Water absorption test;
In a state where the sample tires (10 tires) each having a sound-proofing tool are put up, 3 liters of water is poured and left for 24 hours. Thereafter, water was thrown away, the water on the inner surface of the tire and the surface of the sound control tool was removed with a cloth, the increased weight was measured, and the average value was displayed. Even if there is no noise control, the inner surface of the tire is not completely dry.
A sample tire immediately after the water absorption test was mounted on the right front wheel of a vehicle (2000 cc, FF domestic car) with internal pressure (200 kPa) and rim (15 × 6JJ), and the peripheral circuit was run at a speed (100 km / h). The presence or absence of vibration was evaluated based on the driver's sensation. Of the 10 sample tires, the number of tires in which vehicle vibration occurred was displayed.

(5) Road noise performance;
A tire with a dry sound control device attached is mounted on all wheels of a vehicle (2000cc, FF domestic car) with internal pressure (200kPa) and rim (15x6JJ), road noise measurement path (asphalt rough road) The vehicle interior sound at the driver's seat side ear position when traveling at a speed of 60 km / h was measured, and the sound pressure level of the peak value of the air column resonance sound in the vicinity of the narrow band of 240 Hz was measured. Evaluation was shown by the reduction value on the basis of the case where a noise suppression tool is not mounted | worn. -(Minus) display means a reduction in road noise.

(6) Sound-damping property of the sound absorber when removing the tire;
Using a tire changer (manufacturer name: EIWA, model: WING320) and a tire lever, an operation of removing the tire of the assembly from the rim was performed. Each assembly was removed by 20 workers. The evaluation was performed by measuring the number of times n1 at which damage such as cuts and tears occurred in the noise suppression tool and the number of times n2 at which the noise suppression tool was peeled from the tire lumen surface S1. The smaller n1 and n2, the better.

* 1 to * 5 in the table are as follows.
* 1 Polyisocyanate (T-80: manufactured by Nippon Polyurethane Co., Ltd.)
* 2 Polyester polyol (AH-405: Sanyo Chemical Co., Ltd.),
* 3 Polyester / polyether copolymer polyol (L-50, manufactured by Mitsui Takeda Chemical Co., Ltd.)
* 4 Dimer acid distearyl * 5 Catalyst (Amine, N, N-dimethylaminoatanol (DMAE) ---- 0.3 parts by weight Metal catalyst (Organic acid metal tin salt, Stanas otoate) ---- 0.3 parts by weight Foam stabilizer (SH-193: Torre, manufactured by Silicone Co., Ltd.) ---- 1.0 parts by weight

  Since Conventional Example 1 has high water absorption, it is a major cause of vehicle vibration when exposed to water. In the case of Conventional Example 2, since it is covered with a waterproof sheet, there is no problem in a short time of about 1 hour. However, when exposed to water for a long time, water penetrates from the pinhole and causes vehicle vibration or the like. Tend to cause. In particular, when water enters from a pinhole, there is no method of drying the sponge material other than removing the waterproof sheet, and it is difficult to find the pinhole.

  On the other hand, Examples 1 to 5 can exhibit water-repellent performance while sufficiently securing physical properties such as hardness, tensile strength, and elongation, and can reduce vehicle water absorption and prevent vehicle vibration and the like. It can be confirmed that excellent road noise performance can be demonstrated.

  In Comparative Example 1, since the blending amount of the polyester polyol is less than the range of 3 to 60% by weight, the compatibility between the water repellent and the polyester / polyether copolymer polyol is deteriorated, resulting in poor stirring and repelling. The liquid medicine is not uniformly dispersed. As a result, it can be confirmed that even when the water repellent is properly blended, the water repellent performance cannot be effectively exhibited. However, as in Comparative Example 2, even if the blending amount of the polyester polyol exceeds the range of 3 to 60%, a stirring failure occurs, and the water repellency cannot be effectively exhibited. It becomes difficult to secure the strength as a sound control tool, such as strength and elongation decrease.

  Further, as in Comparative Example 3, when the blending amount of the water repellent exceeds the range of 25 to 80 parts by weight, the water repellent acts as a plasticizer, so that the foam cannot be molded. However, when the blending amount of the water repellent is less than the range of 25 to 80 parts by weight, the water repellent performance is not effectively exhibited as in Comparative Example 4.

  If there is too little water as a foaming agent, as in Comparative Example 5, sufficient foaming is not obtained and the specific gravity of the sponge material becomes excessive, reducing road noise performance and increasing tire weight and weight balance. This is disadvantageous for tires.

  In addition, as compared with Example 3 and Examples 6 and 7, the cross-sectional noise control device (Examples 6 and 7) of FIGS. 5A and 5B is damaged when the tire is removed from the rim. It can be confirmed that it can be used for a long period of time by repeatedly attaching to and removing from the rim.

It is sectional drawing which illustrates one form with which the noise suppression tool of this invention was attached to the assembly of a tire and a rim | limb. It is sectional drawing of the circumferential direction along the tire equator. It is sectional drawing which shows the free state of a noise suppression tool. It is a side view which shows an example of the inclined surface part in the circumferential direction outer end part of a noise suppression tool. (A), (B) is sectional drawing which illustrates other embodiment of a noise suppression tool. It is a perspective view of the apparatus explaining a water repellency test.

Explanation of symbols

2 Pneumatic tire 3 Rim 4 Tire lumen 5 Damping tool 6 Base S1, S2 Lumen surface

Claims (3)

A tire noise control device installed in a tire lumen formed by a rim and a pneumatic tire mounted on the rim,
A base material made of a sponge material having a specific gravity of 0.005 to 0.060, fixed to the inner rim surface or the inner luminal surface of the tire and extending in the tire circumferential direction;
The sponge material comprises a water-repellent polyurethane foam obtained by foam-curing a mixed composition containing a polyisocyanate, a polyol, a water repellent and a foaming agent, and the polyol is a polyester polyol and a polyester / polyether copolymer. Mixed with polyol,
Moreover, the polyol is composed of 3 to 60% by weight of polyester polyol and 97 to 40% by weight of polyester / polyether copolymer polyol, and the water repellent is 25 to 80% by weight based on 100 parts by weight of polyol. with parts being formulated,
The water repellent is an ester, and is a conjugate of a monoalcohol having 14 to 36 carbon atoms and an aliphatic dicarboxylic acid or alicyclic dicarboxylic acid having 14 to 36 carbon atoms. Sound tool.   2. The tire noise control device according to claim 1, wherein the foaming agent is water, and the blending amount thereof is 2.5 to 6.0 parts by weight with respect to 100 parts by weight of polyol. The polyol comprises 15 to 35% by weight of polyester polyol and 85 to 65% by weight of polyester / polyether copolymer polyol,
3. The tire sound control device according to claim 1 , wherein the water repellent is blended in an amount of 30 to 50 parts by weight based on 100 parts by weight of polyol .

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