JPH08268007A - Puncture-less tire, foaming body filler used for the tire and manufacture of the foaming body filler - Google Patents

Abstract

PURPOSE: To provide a foaming body filler usably inserted in a puncture-less tire and tire balanced between the rolling resistance and cushion property and a method for manufacturing the same. CONSTITUTION: A puncture-less tire 1 has a foaming body filler 7 inserted in the inner peripheral part 6 of a tire 2 consisting of a tread part 3, side wall part 4 and bead part 5. The foaming body filler 7 is obtained from polyol, poly isocyanate, catalyst, foaming agent, or the like and the polyol is at least one kind of polyetherpolyol containing at least 7,000 molecular weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a puncture tire, a foam filler used for the puncture tire, and a method for producing the foam filler. More specifically, the invention relates to a puncture tire having improved rolling resistance and drum running durability. The present invention relates to a foam filler to be used by inserting it into a tire and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, it is well known to fill a hollow portion in a tire with a urethane resin to manufacture a puncture-less tire. For example, Japanese Patent Publication No. 57-15002, Japanese Patent Publication No. 1-24641, Japanese Patent Publication No. 55-411.
JP-B, JP-B-58-18245, JP-A-52-
111996 and the like propose a method of manufacturing a puncture tire by pouring a liquid urethane undiluted solution into a space with the tire and the rim fitted, and a material formulation with high impact resilience. Since these are intended for vehicles with relatively high loads and low speeds such as truck tires, industrial tires, and agricultural tires, non-foamed urethane elastomers are usually used.

On the other hand, the filling material for light vehicles such as bicycles and wheelchairs is used in a low load and low speed range, so that it is considered that the weight and the physical properties are well balanced. Therefore, urethane foam is often used.
The manufacturing method includes, as described above, a method of pouring a liquid urethane undiluted solution into the space with the tire and the rim fitted, and a donut-shaped foam filler that is separately prepared later in the space of the tire and the rim. There is a way to fit.

The former method can be used when manufacturing standardized wheels on the factory side, but cannot repair or replace the wheel components on the terminal side. On the other hand, the latter has the advantage that it can easily replace the pneumatic filler and is used in some cases.

[0005]

However, it is not in a situation where foam fillers are a broad replacement for pneumatic fillers. This is because there is a problem in rolling resistance and cushioning property as compared with the pneumatic filler. Generally, there is a trade-off relationship between rolling resistance and cushioning. The rolling resistance is due to the compression hysteresis loss of the foam. Therefore, if it is hardened to reduce deformation, rolling resistance is improved,
The cushioning property is impaired. On the other hand, if it is softened to improve the cushioning property, the rolling resistance deteriorates due to hysteresis loss, and if it is extremely large, foam scratches break due to heat generation in the durability test.

Therefore, if a foam having a high impact resilience with less hysteresis loss can be obtained as a material, a foam filler having a well-balanced rolling resistance and cushioning property can be obtained.
The market for punctureless tires for light vehicles using this is expected to expand. The present invention is to improve such problems, a flat tire having a well-balanced rolling resistance and cushioning property, a foam filler to be used inserted into the tire, and a method for producing the foam filler. The purpose is to provide.

[0007]

That is, the features of the present invention are as follows:
A tread portion, a side wall portion, and a flat tire having a bead portion inserted in the inner peripheral portion of the tire, wherein the foam filler is obtained from a polyol, a polyisocyanate, a catalyst, a foaming agent, or the like. ,
A puncture-less tire in which the polyol is at least one polyether polyol containing a polyether polyol having a molecular weight of 7,000 or more. Further, the present invention is a flat tire in which a foam filler is inserted into a tire tread portion, a side wall portion, and a bead portion, and the foam filler is a polyol, a polyisocyanate, a catalyst, or a foaming agent. And the like, and also includes a puncture tire using a polyether polyol as the polyol, and a polyol selected from a polybutadiene polyol, a polytetramethylene ether glycol, and a polyester polyol that is liquid at room temperature.

Furthermore, the present invention provides a foam filler for a puncture tire, which is used by inserting it into the inner peripheral portion of the tire,
The foam filler is a polyol, polyisocyanate,
A foam filler for a puncture tire, which is obtained from a catalyst, a foaming agent or the like, and in which the above-mentioned polyol is at least one polyether polyol containing a polyether polyol having a molecular weight of 7,000 or more is also included. Further, the present invention, in a foam filler for a puncture-less tire to be used inserted into the inner peripheral portion of a tire, the foam filler is obtained from a polyol, polyisocyanate, a catalyst, a foaming agent, or the like. It also includes a foam filler for a puncture tire, in which the polyol contains a polyether polyol and, in addition, a polyol selected from polybutadiene polyol, polytetramethylene ether glycol, and a polyester polyol that is liquid at room temperature. The present invention also includes the case where the polyester polyol that is liquid at room temperature is a polyol selected from at least diethylene adipate, neopentyl adipate, and propylene adipate.

Furthermore, the present invention is a method for producing a foam filler for a puncture-less tire which is used by inserting it into the inner peripheral portion of a tire, in which two stock solutions consisting of a polyether polyol, a catalyst, a foaming agent, etc. and polyisocyanate are used. After mixing by collision and casting in a mold, the gate is closed and the mold is rotated, the unreacted mixture is pressed against the outer peripheral part of the mold, and foam molding for a puncture tire for foam molding toward the inner peripheral side Including manufacturing method. The present invention also includes a manufacturing method in which the mold has an air vent groove on the parting surface located on the inner peripheral side.

As shown in FIG. 1, the punctureless tire 1 of the present invention has a tire 2 comprising a tread portion 3, a side wall portion 4 and a bead portion 5, and a foam filler 7 inserted in the inner peripheral portion 6. It consists of a structure. This tire 2
Has no particular structural features, like the rubber-filled pneumatic tube. The foam filler 7 is shown in FIG.
The cross section is almost circular as shown in Fig.
have. The tongue portion 8 has a function of pressing the bead portion against the rim side to prevent the tire from coming off the rim. However, if it is too large, it will be difficult for the foam filler together with the tire to fit on the rim. The foam filler 7 is a polyol containing a long-chain polyol and a short-chain polyol,
It is a urethane foam synthesized from a polyisocyanate and a polyol blend in which a foaming agent, a catalyst and the like are uniformly blended. The present invention is characterized by the foam filler 7.

The long-chain polyols used for producing the foam filler 7 include polyether polyols, polybutadiene polyols, polytetramethylene ether glycols, and normal-temperature liquid polyester polyols. In particular, polyether polyols are widely used because they are inexpensive and have excellent hydrolysis resistance.

In the above polyether polyol, alkylene oxide such as propylene oxide or ethylene oxide is added to the initiator, and after ring-opening polymerization, the reaction is completed by neutralizing with an acid or the like. Various quality products can be obtained depending on the kind of the initiator, the propylene oxide / ethylene oxide ratio, the position of ethylene oxide block addition, the amount of propylene oxide or the amount of propylene oxide / ethylene oxide added, and the like.

When a bifunctional one such as ethylene glycol is used as the initiator, a long-chain diol is synthesized, and when a trifunctional one such as glycerin or triethanolamine is used, a long-chain triol is obtained, When a tetrafunctional diglycerin or the like is used, a long-chain tetraol is synthesized. In this way, the functional number of the long-chain polyol is determined by the functional number of the initiator, and those having a functionality of 6 or more are synthesized, but in the ordinary semi-rigid urethane foam, a long-chain polyol having a functional number of 2 to 4 is used. . The alkylene oxide is mainly propylene oxide, and an ethylene oxide block is often added to the terminal to increase the primary hydroxyl group ratio and the reaction activity. The obtained polyether polyol has a molecular weight of 1,000 to 7,000, but recently, there is one having a molecular weight of 7,000 or more.

In the present invention, it is possible to use at least one kind of polyether polyol including the above long-chain polyether polyol having a molecular weight of 7,000 or more. That is, a long-chain polyether polyol having a molecular weight of less than 7,000 can be added to a long-chain polyether polyol having a molecular weight of 7,000 or more. It has been found that the use of a long-chain polyether polyol of 7,000 or more has excellent rolling resistance and drum running durability of the obtained puncture tire. Of course, in the present invention, a long-chain polyether polyol having a molecular weight of 1,000 to 7,000 and a long-chain polyol selected from a polybutadiene polyol, a polytetramethylene ether glycol, and a polyester polyol which is liquid at room temperature are also used. It can be added and used.

The above polybutadiene polyol is a polymer of butadiene having a hydroxyl group at the terminal, or a copolymer of butadiene and styrene or acrylonitrile. It has a higher viscosity than the polyether polyol.

The above-mentioned polytetramethylene ether glycol is obtained by cationic polymerization of tetrahydrofuran and has a molecular weight of about 500 to 2,000. Although it is a solid at room temperature, the modified product copolymerized with alkylene oxide is a liquid at room temperature.

The normal temperature liquid polyester polyol comprises diethylene adipate using diethylene glycol as a glycol, neopentyl adipate using neopentyl alcohol, propylene adipate using propylene glycol, and the like. It is inferior in hydrolysis resistance to the polyether polyol.

On the other hand, the short chain polyol is used as a chain extender, and the hardness is adjusted by the addition amount. Usually, ethylene glycol, 1.4-butanediol, triethanolamine, trimethylolpropane and the like are used, but not particularly limited.

As the foaming agent, a solvent such as CFC, CFC substitute, halogen-based organic solvent and other combustible organic solvent can be used, but water is preferable in view of environment and safety and hygiene.
However, it is not particularly limited to this. Changing the expansion ratio depending on the amount of the foaming agent added is one method of adjusting the hardness. The expansion ratio is usually 1.5 to 2.5 times.

As the catalyst, a tertiary amine such as triethylenediamine or organic tin is used. However, it is not particularly limited to this. In addition to the above, colorants, foam stabilizers, fillers, stabilizers and the like are added as necessary. However, puncture tires and foam fillers
Since it is preferable to use a closed-cell body that does not easily absorb water and has a low rolling resistance, when a foam stabilizer is used, it is necessary to select one having a small open-cell effect.

Polyisocyanate is hexamethylene diisocyanate, 2.4-toluene diisocyanate,
2.4 / 2.6-toluene diisocyanate, 1.5-
There are naphthalene diisocyanate, 4.4'-diphenylmethane diisocyanate (pure MDI), polymeric MDI (crude MDI), etc., usually 4,4'-
A liquid obtained by modifying diphenylmethane diisocyanate (MDI) is used. As a modification method, there are a method of reacting with a polyol to form a prepolymer and a method of dimerizing (carbodiimide).

As for the mixing of the above-mentioned compounds, a one-shot method is generally used in which an additive other than polyisocyanate is first prepared as a polyol compound, and this is mixed with polyisocyanate to carry out an injection reaction. However, a prepolymer method may be used in which a part of the polyol is reacted with the polyisocyanate in advance to form the prepolymer.

As a method for mixing the polyol blend and the polyisocyanate, for example, there is a method using a high pressure casting machine (RIM machine). In this, two liquids are metered and circulated at around 150 atm by a high-pressure pump, the discharge port is opened for a predetermined time, and the two liquids are mixed by collision. The opening and closing of the discharge port is performed by moving the piston backward or forward by the operation of hydraulic pressure. Since the so-called self-cleaning mechanism is provided in which the two-liquid mixture on the wall surface is scraped off when the piston advances, it is not necessary to wash the solvent for each discharge.

Another method is to use a low pressure casting machine. This is to measure and circulate the two liquids with a low pressure pump of several atmospheres, open the discharge valve for a predetermined time, introduce the two liquids into the mixing chamber, and discharge the liquid while stirring with a rotor. With this method, a foam with good stirring can be obtained, but it is necessary to wash the mixing chamber with an organic solvent such as methylene chloride after each discharge.

As a method for injecting the two liquids into the mold, an open casting mold in which a mold placed substantially horizontally is opened, a mixed liquid is injected into the lower mold cavity, and then the mold is closed and foam curing is carried out is also possible. It may be a closed casting mold that is press-fitted from the gate in a closed state. However, in both the above-mentioned open casting and closed casting, after injecting the mixed solution, the mold is rotated as quickly as possible, and the mixed solution before foaming is pressed by the centrifugal force to the outer peripheral side of the ring-shaped mold, Foam towards the side,
It is necessary to bleed air from the air bleed groove provided on the parting surface on the inner peripheral side.

The mold can be rotated so as to oscillate about a horizontal plane, a vertical plane, or a rotation axis, and at least 3 G, preferably 5 G, is added to the mixture before foaming on the outer periphery of the mold.
Adjust the rotation speed so that a centrifugal force of G or more is applied. 3G
Below, a foam having a uniform density distribution cannot be obtained,
Further, even if a centrifugal force of 10 G or more is applied, the capacity of the motor increases and the required power increases, but there is no advantage. It should be noted that when the mold is rotated, it is necessary to start it earlier than the reaction start of the mixed solution, and the time varies depending on the compounding, but it is within 5 seconds in the compounding formulation considering productivity. Therefore, closed casting is more common than open casting.

The mold used here is a donut type in which a ring-shaped upper mold and a lower mold are combined. The lower mold is connected to the rotary shaft of the rotating device, and the central part is connected to the mixing head of the casting machine. Have a gate to A plurality of spool runners diverge radially from the gate and connect to a cavity that molds the fill material around the perimeter. An air vent groove is provided on the parting surface on the inner peripheral side. The material of the mold may be any of resin, ZAS, aluminum, steel, etc., but a lightweight one is preferable because it is rotated.

[0028]

The present invention will be described in more detail with reference to the following examples. Examples 1 to 4 and Comparative Examples 1 to 3 Compounds shown in Table 1 and a high-pressure casting machine for testing (Battenfe)
A urethane foam filler was prepared by the following method. First, a mold release agent was applied to a horizontally installed mold, the mold was clamped, the mold temperature was maintained at 50 ° C., and then the mixing head of a high-pressure casting machine was connected to the mold. Approximately 1 second, 850 g of the polyol compounding agent and 2 liquids of polyisocyanate were collision-mixed and discharged into the mold for about 1 second after opening the discharge port. After about 5 seconds, the mixing head was released from the mold to close the gate, and the closed mold was rotated at 120 rpm for 1 minute and stopped. After 4 minutes, the safety cover was opened, the mold was opened, and the molded body was demolded. This was post-cured at 60 ° C. for 4 hours to obtain a foam filler. The product weight was 790 g.

However, only in Comparative Example 3, the mold was not rotated, the mold was tilted 30 ° from the horizontal plane, and the mold was poured from below.
Air was vented together with some raw materials from an air vent hole having a diameter of 3 mm provided at the top.

[0030]

[Table 1]

The urethane foam filler thus obtained was evaluated according to the following evaluation items. The results are shown in Table 2.

1. Internal void The urethane foam filler was slice-cut and visually checked for the presence of internal voids.

2. JIS C hardness The surface hardness of the urethane foam filler was measured with a JIS C hardness meter at 23 ° C.

3. Impact resilience Cut urethane foam filler, JIS K630
A test piece for impact resilience was prepared according to 1.
It was measured by K6301.

4. Hysteresis loss Bicycle tire 26 x 1/3/8 (manufactured by Mitsuboshi Belting,
A urethane foam filler was set on a MW258 pattern (all black tires) and fitted to an iron rim to fix the hub core. This is autographed with a compression speed of 100 mm
/ Min, compress up to 400N, unload at the same speed and draw a compression curve and unloading curve on the chart.
The area B of the portion surrounded by the two curves was divided by the area A of the compression curve to obtain the value by the following formula. Hysteresis loss (%) = B / A x 100

5. Deflection under load of 400 N As with the hysteresis loss, it was read from the chart obtained from the compression test.

6. Rolling resistance A urethane foam filler was set on the above bicycle tire, fitted into a rim for measuring rolling resistance, and rolling resistance was measured with a road surface characteristic tester at a load of 400 N and a running speed of 30 km / hour.

7. Drum running durability Set the urethane foam filler to the above bicycle tire and fit it on the rim for drum running durability measurement.
Based on K6302, load 70 with a drum running tester
The filler was sliced and cut at a traveling speed of 0 N and a traveling speed of 40 km / hour for 5,000 km, and the presence or absence of damage was visually confirmed.

[0039]

[Table 2]

As a result, in Example 1, since a high-molecular-weight polyol was used as the polyether polyol, the rolling resistance was small as compared with Comparative Example 2, although the rolling resistance was small. In Comparative Example 1, an ordinary general-purpose polyether polyol is used for softening,
It can be seen that rolling resistance and drum running durability are poor. Further, in Examples 2, 3 and 4, polybutadiene polyol, polytetramethylene ether glycol, and polydiethylene adipate are substituted for some of the general-purpose polyether polyols of Comparative Example 1, respectively, but the softness is almost the same and the rolling resistance is almost the same. And the improvement of drum running durability is recognized. Further, in Comparative Example 3, a filler having a good appearance was obtained, but since the mold was not rotated, voids remained inside, and the rolling resistance was worse than in Example 1.

[0041]

As described above, in the present invention, at least one polyether polyol containing a polyether polyol having a molecular weight of 7,000 or more is used as the polyol, and the molecular weight of the polyol is 1,000 to 7.0.
00 Polyol polyol and other polyols selected from polybutadiene polyol, polytetramethylene ether glycol, and polyester polyol that is liquid at room temperature are used, so rolling resistance, drum running durability, and cushioning properties are improved. Excellent puncture-less tire and foam filler can be obtained, and after the two undiluted solutions are impinged and mixed into the mold, the gate is closed and the mold is rotated, so there is no void inside and uniform. There is an effect that it is possible to manufacture a foam filler having a wide density distribution.

[Brief description of drawings]

FIG. 1 shows a cross-sectional view of a flat tire according to the present invention.

FIG. 2 shows a cross-sectional view of a foam filler according to the present invention.

[Explanation of symbols]

 1 Punkless Tire 2 Tire 3 Tread Part 4 Sidewall Part 5 Bead Part 6 Inner Perimeter 7 Foam Filler 8 Tongue

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09J 175/08 JFB C09J 175/08 JFB (72) Inventor Hirohide Enami 4 Hamamazodori, Nagata-ku, Kobe 1-21 Mitsuboshi Belting Co., Ltd.

Claims (8)

[Claims] 1. A flat tire in which a foam filler is inserted into an inner peripheral portion of a tire composed of a tread portion, a sidewall portion, and a bead portion, wherein the foam filler is a polyol, a polyisocyanate, a catalyst, a foaming agent, or the like. A puncture-less tire, characterized in that the polyol is at least one polyether polyol containing a polyether polyol having a molecular weight of 7,000 or more. 2. A flat tire in which a foam filler is inserted into an inner peripheral portion of a tire including a tread portion, a sidewall portion, and a bead portion, wherein the foam filler is a polyol, polyisocyanate, catalyst, foaming agent, or the like. A puncture-less tire characterized by using a polyether polyol as the polyol, and a polyol selected from a polybutadiene polyol, a polytetramethylene ether glycol, and a polyester polyol which is liquid at room temperature as the polyol. 3. The puncture-less tire according to claim 2, wherein the polyester polyol which is liquid at room temperature is a polyol selected from at least diethylene adipate, neopentyl adipate and propylene adipate. 4. A foam filler for a flat tire, which is used by inserting it into the inner peripheral portion of a tire, wherein the foam filler is obtained from a polyol, a polyisocyanate, a catalyst, a foaming agent or the like. Has a molecular weight of 7,
A foam filler for a puncture tire, which is at least one polyether polyol containing 000 or more polyether polyols. 5. A foam filler for a puncture tire, which is used by inserting it into an inner peripheral portion of a tire, wherein the foam filler is obtained from a polyol, a polyisocyanate, a catalyst, a foaming agent or the like. Is a polyether polyol, and other is a polybutadiene polyol,
A foam filler for a puncture-less tire, which contains polytetramethylene ether glycol and a polyol selected from polyester polyols which are liquid at room temperature. 6. The foam filler for a puncture-less tire according to claim 5, wherein the polyester polyol which is liquid at room temperature is a polyol selected from at least diethylene adipate, neopentyl adipate and propylene adipate. 7. A method for producing a foam filler for a puncture-less tire which is used by inserting it into an inner peripheral portion of a tire, wherein two undiluted solutions consisting of a polyether polyol, a catalyst, a foaming agent and the like and a polyisocyanate are mixed by collision. After filling the mold, the gate is closed, the mold is rotated, the unreacted mixture is pressed against the outer peripheral portion of the mold, and foam molding is performed toward the inner peripheral side. Manufacturing method. 8. The method for producing a foam filling material for a puncture-less tire according to claim 7, wherein the mold has an air vent groove on a parting surface located on the inner peripheral side.