KR840000608B1 - Elastomer tire filling material - Google Patents

Abstract

Elastomer tire-filling material is prepd. by reacting prepolymer (A) contg. an isocyanate end gp., with a hardener (B) contg. hydroxy or amino end gp., where the ratio of the number of NCO in prepolymer (A) to the number of OH or NH2 in the hardner (B) is 0.7-1.3. (A) is obtd. by reacting the OH end gp. contg. dienpolymer (C) whose m.w. is less than 10000, with a diisocyanate compd. where the ratio of the number of NCO in diisocyanate to the number of OH in the polymer (C) is 1.6-3.0.

Description

Tire Filler Composition

TECHNICAL FIELD The present invention relates to a tire filler composition, and more particularly, to a urethane-based tire filler composition having excellent resilience and moderate hardness.

So-called elastic tires filled with elastic bodies are expected to be used as tires for general vehicles such as buses and subways because they have better load capacity and no risk of puncture compared to pneumatic tires. In particular, in the case of using a urethane-based polymer as a filler, a method of injecting a liquid prepolymer into a cavity of a preliminarily-rimmed tire and reacting the polymer with a suitable hardness in the tire is used. It has the advantage of easy tire processing.

As a urethane-based elastic body conventionally used, it was an elastic body obtained from the following) (referred to as "OH group") terminal polyether or OH group terminal polyester and diisocyanate, that is, polyurethane based on polyether or polyether at the time of a hydroxyl. For example, "TYRFIL" (Synair mapping table) is known as a reactant of a mixture of polyoxypropylene glycol and polyoxypropylene triol and tolylene diisocyanate (hereinafter abbreviated as TDI).

However, such a conventional urethane-based elastic body had the following drawbacks.

(1) Tire fillers require high rebound modulus and moderate hardness, but conventional urethane-based elastomers have excessively high hardness when the resilient elasticity is increased, and low resilience when the hardness is reduced.

(2) When the tire is filled and used repeatedly, the urethane elastic body generates heat in the tire and is unable to withstand stress, and is broken into pieces, deteriorated, melted, and prescribed. Impairs elasticity and spring constant.

As a method of resolving such a problem, for example, the reason why the urethane elastomer deteriorates is that the tire-containing amine-based antioxidant is shifted toward the urethane, and butyl halide or rubber containing the same is determined between the elastomer and the rubber. A method of forming a layer has been proposed but has not reached the essential solution.

In addition, there are cyanides that form isocyanurate rings generally known to have good heat resistance at the same time as the urethane elastic body is produced and cured. However, in the milder conditions as in the production of ordinary urethane elastomer, The formation of an anurate ring is suspicious, and even if a sisocyanurate ring is formed, its concentration is low, and thus improvement of heat resistance cannot be expected. On the contrary, in the case of increasing the amount of isocyanurate ring to contribute to improving heat resistance, The hardness, rebound elasticity, elasticity, etc. of a urethane elastic body do not correspond with a desired value.

The present invention is to solve the above-mentioned drawbacks to provide a tire filler composition having excellent resilience, moderate hardness, workability and low internal heat generation even after running the tire after filling the tire and does not inhibit the riding comfort The purpose.

That is, the present invention has a prepolymer having an isocyanate group at the terminal obtained by reacting a polymer (C) containing a diene polymer having a molecular weight of 1,000 or less and a diisocyanate compound at a ratio of the following range (II) at least at the terminal ( The elastic tire filler composition obtained by reacting A) and the hardening | curing agent (B) which consists of a compound which has a hydroxyl group or an amino group at the terminal in the ratio of the following range (I).

1.3(I): 0.7

1.3

3.0(II): 1.6

3.0

The diene polymer used in the present invention contains OH groups in the sock end of the side chain, and is, for example, a liquid or semi-solid polymer obtained by polymerizing a C ₄ -C ₅ conjugated diene monomer. The method described in the publication as Japanese Patent Publication Nos. 30103 and 30104, a method of polymerization using an organometallic catalyst such as alkyl Li as an initiator and ethylene oxide or the like as a terminator, or an initiator containing an OH group The method to be used or the method of oxidizing a normal diene polymer and adding an OH group to a cleavage side chain may be sufficient.

In addition to the diene monomers, vinyl compounds such as styrene, acrylonitrile, acrylic acid and acrylic acid esters may be used in a proportion of less than 30 parts with respect to 100 parts of diene monomer.

Such diene polymers of the present invention need to contain OH at both ends and have a molecular weight of 10,000 or less.

If the molecular weight is too high, it is reacted with diisocyanate to increase the viscosity at one time as a prepolymer, making the filling operation difficult.

The polymer backbone of the present invention may be a diene polymer alone, but also preferably contains a polyoxyalkylene polymer.

The polyoxyalkylene polymer used in the present invention is a compound containing two active hydrogens such as glycols such as ethylene glycol, propylene glycol, 1,4-butanediol or triols such as glycerin and trimethylol propane, and monoethanol. Compounds containing three active hydrogens, such as amino alcohols such as amines, or compounds containing four active hydrogens, such as gudroool and pentaerythritol ethylenediamine, are used as starting materials. It is obtained by ring-opening-polymerizing a seed, an organic sedan, tetrahydrofuran, etc.

Thus, the molecular weight of this polyoxyalkylene polymer should be 200-4,000 per active hydrogen described above, and the molecular weight as a whole should be 10,000 or less.

By adding polyoxyalkylene polymer to the diene polymer to obtain isocyanate prepolymer, the viscosity of the prepolymer is lower than that of the isocyanate prepolymer of diene polymer alone, so it is excellent in workability and contains polyoxyalkylene in the prepolymer skeleton. When using the thing containing a polyalkylene bond in frame | skeleton as a hardening | curing agent, favorable compatibility and uniform hardened | cured material are obtained, and the tire filler composition thus obtained is very stable.

Examples of the diisocyanate compound used in the present invention include hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate mixture (mixing ratio is 2,4-isomer) / 2,6-isomer = 80/20 or 65/35), xylene diisocyanate, tolidine diisocyanate, 4,4'-diphenylmethane diisocyanate, phenylene diisocyanate (including mp-form), methylene Bis (2-methyl-p-phenylene) diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate And 1 type or mixtures, such as a saturated cyclic diisocyanate compound and isohorone diisocyanate obtained by hydrogenating the said aromatic diisocyanate, are used.

When reacting such a diene polymer and a diisocyanate, it is necessary to make the stoichiometric ratio (NCO / OH) of the NCO in a diisocyanate group and the OH group in a diene polymer into 1.6-3.0.

Whether the diene polymer and the polyoxyalkylene polymer are respectively reacted with diisocyanate alone or the diisocyanate is reacted with a mixture of the diene polymer and the polyoxyalkylene polymer. The stoichiometry (NCO / OH) of OH groups and OH groups in polyoxyalkylene polymers needs to be in the range of 1.6-3.0.

When NCO / OH is 1.6 or less, since the molecular weight of the produced terminal isocyanate prepolymer becomes large and a viscosity rises, it becomes difficult to fill a tire.

When the NCO / OH exceeds 3.0, the viscosity decreases, but the reactivity of the NCO group in the diisocyanate that does not react with the OH group is high, making adjustment of the reaction difficult, and decreasing the mean molecular weight of the prepolomer in the final polymer. Urethane bond density becomes high and hardness increases.

Therefore, it is necessary to make NCO / OH 1.6-3.0 at the stage of a prepolymer.

In the present invention, the prepolymer of terminal NCO obtained as described above is injected into a tire together with a curing agent to cure. As a hardening | curing agent, although the compound contains an OH group or an amino group at the terminal, the following are used.

OH group terminal diene polymer used when preparing the above-mentioned prepolymer, ethylene oxide or propylene oxide addition polymerization of ethylene oxide or propylene oxide to the OH group terminal diene polymer within 10 moles, polyether polyol, 1, Fertilizer low molecular weight polyol OH group-containing vegetable oils such as 4-butanediol, trimetholpropane, 1,6-hexanediol, glycerin, castor oil, diethylene glycol, and polyalkylene oxides of terminal amino groups [for example, Jefferson Jefferson Chem. CO. Jane Zeperamine D-2,000], amine-terminated acrylonitrile butadiene copolymers (e.g., ATBN 1,300 × 16 from BF Goodrich Chemicals) 1 type, or a mixture thereof.

The reaction ratio between the prepolymer and the curing agent described above needs to make NCO / OH or NH ₂ 0.7-1.3, and 0.8-1.15 is suitable. Since the prepolymer of the present invention has NCO groups at both ends, the amount of NCO is calculated by measuring the molecular weight of the prepolymer. When the ratio of NCO in the prepolymer and OH or NH _{2 in} the curing agent is less than 0.7, the curing becomes slow and the physical properties, particularly elongation, of the resulting cured product are poor. On the contrary, when it exceeds 1.3, the physical properties of the cured product change over time, resulting in poor elongation and tensile strength.

The polyurethane of the present invention thus obtained uses at least a diene-based polymer in its backbone, and thus has high resilience and moderate hardness compared to polyether or polyester-based polyurethanes used for tire filling in the related art. . The reason for this is that the diene-based polymer is considered to be due to less dynamic loss than polyether or polyester.

In the preparation of the isocyanate prepolymer, diisocyanates having good symmetry are reacted in advance, and then asymmetric diisocyanates such as doriren diisocyanate are reacted or added to control the reactivity and at the same time, a highly reactive agent as a curing agent. By using a primary OH group or NH ₂ , the reaction can be completed to obtain a tight cured product, thereby obtaining a tire filler that can withstand high loads or repeated fatigue.

It is preferable that the tire filler of the present invention has the following physical properties.

That is, it is necessary that the strength by JIS (Japanese Industrial Standard) is 15-45 degree | times (25 degreeC), and repulsive elasticity (Ryubou repulsive elasticity) is 50% or more at 25 degreeC, and 70% or more at 100 degreeC.

Hardness is related to tire curvature when a load is applied. For example, when the hardness is less than 15 degrees, the tire curvature tends to generate heat during melting and melt the filler. In addition, when the hardness exceeds 45 degrees, the buffering effect is lowered and the car stopper is poor, which is not suitable.

The higher the rebound elasticity is, the more rapid the reaction is against the dwarf force, and the less the heat accumulation due to the deformation and the dwarf force is suitable. However, it is sufficient to be more than 50% at 25 ° C and more than 70% at 100 ° C. .

In order to properly form the tire filler composition of the present invention in a tire, it is preferable to appropriately adjust the viscosity of the mixture of the prepolymer to be injected into the tire and the curing agent, and the viscosity at least 10-50 ° C. should be 100 poise or less. do. The reason is that if the viscosity is too high, it is difficult to press-fit into the tire, and if the temperature is raised to lower the viscosity, the reaction rate increases, which is not suitable.

For example, when injecting into a 1,000R-20 size tire, it usually takes about 40 minutes to 2 hours, so it is necessary to use a low viscosity prepolymer in advance in consideration of the increase in viscosity due to the reaction. .

Of course, this viscosity is a problem of the viscosity of the point to be injected into the tire, so even if the viscosity of the original polymer is high, it is possible to lower the viscosity by mixing Yir or by mixing a plasticizer described later, but the molecular weight of the diene polymer It is necessary to use less than 10,000.

As the plasticizer, it is necessary to select a good compatibility of the final polymer, aliphatic dicarboxylic acid esters, aromatic dicarboxylic acid esters, glycoester esters of monocarboxylic acids, rubber process oil, binder, polybutene, inert liquid polymer And the like, but in large quantities, the rebound elasticity is lowered, so it should be used in an amount of 100 parts or less, suitably 50 parts or less with respect to 100 parts of the polymer.

For the purpose of promptly curing the above-mentioned mixtures injected into tires, catalysts of urethane reactions, ie tertiary amines such as triethylenediamine, triethylenetetramine or amino alcohols, 1.8-diazabicyclo (5, 4, 0) Undecene-7 and its salts, imidazole or organic Sn compounds, organic Fe compounds and the like are used.

As these catalyst amounts, 0.1 part or less is suitable with respect to 100 parts of prepolymers.

In addition, graphite, carbon black, clay, talc, silica, and the like may be added as fillers. However, when added in large amounts, 10 parts or less is suitable for 100 parts of polymer because hardness increases or repulsive elasticity decreases. It is believed that the effect of the filler is on the suppression of local fever, but for example, in the case of graphite, when the particle diameter is 150 μ or more, it exhibits a physical effect, and the dynamic fatigue is extremely poor. The particle diameter must be 150 μ or less.

The present invention will be described in detail with reference to the following Examples.

Example 1

Liquid polybutadiene containing OH at the end (1,4-trans 60%, 1,4-cis 20%, 1,2-vinyl 20% chemical structure with a number average molecular weight of 2,700-3,00.) 14.7 parts of 80/20 2,4- / 2,6-dorirene diisocyanate (hereinafter referred to as TDI) with 100 parts of ACO Chemical R45M) was attached with a stirring device in the presence of an inert gas (dry N ₂ ). It was added to the reaction vessel and reacted at 60 ° C for 8 hours.

NCO / OH was about 2.36 in this reaction. As a result, a prepolymer containing an NCO group at the sock end was obtained.

Next, 100 parts of the mixture of 111 parts of R45M described above as a curing agent, 20 parts of dioctylphthalate as a plasticizer and 0.046 parts of octyl acid as a catalyst were added to 100 parts of the prepolymer obtained, and the mixture was mechanically mixed well. This was used to fill a tire of a size of 1,000 R20. The ratio NCO / OH of the NCO group in the prepolymer at this time and the OH group in the curing agent was 1.13.

The semi-cured urethane resin thus obtained was cast in a mold mold for measuring the rebound elastic modulus, and the hardness and rebound elasticity of the cured product obtained by curing under the same curing conditions as those of the tire were measured. Shown in

Comparative Example 1

100 parts of polyoxypropylene triol (Mw 1,000) and 60 parts of 80/20, 2,4- / 2,6-TDI were made to react (NCO / OH = 2.3) and the terminal NCO prepolymer of molecular weight 1,510 was obtained. 230 parts of polyoxypropylene glycol (Mw 2,000) was mixed with 100 parts of this prepolymer (NCO / OH = 1.0) and filled in the tire in the same manner as in Example 1.

The tires of Example 1 and Comparative Example 1 were pressed against a drum of 1.6 m diameter with a smooth surface under a load of 3,000 kg, and subjected to an endurance test under the same driving conditions with an ambient temperature of 35 ° C. and a speed of 60 km / hr. The results are shown in Table 1.

TABLE 1

* Melting and driving

In Table 1, the hardness is the same, but the rebound modulus is excellent in the packing material of the present invention.

Comparative Example 2

1,000)을 121부 혼합한(NCO/OH=0.95) 것은 경도 48도, 반발탄성 60% (25℃), 85% (100℃)이었으나 타이어로서 사용할때 2,000㎞주행함으로서 충진물에 균열이 생겨 주행이 불가능하게 되었다.Polyoxypropylene glycol (as a curing agent) in 100 parts of the same prepolymer as in Comparative Example 1 (

(NCO / OH = 0.95) of 121 parts of 1,000) was 48 degrees of hardness, 60% of rebound elasticity (25 ℃) and 85% (100 ℃), but when it was used as a tire, it ran 2,000km, causing cracks in the filling. It became impossible.

Example 2

Liquid polybutadiene containing an OH group at the end (1,4-trans 60%, 1,4-cis 20%, 1,2-vinyl 20% chemical structure and has a hyphae molecular weight of 2,800.) 4,4-diphenylmethane diisocyanate (hereinafter referred to as MDI) by mixing 20 parts of polypropylene glycol (molecular weight: about 2,000) with 80 parts of manufactured R45HT). 20 parts by filling a reaction vessel equipped with a stirrer in an inert gas (dry N ₂₎ was allowed to react for 1 hour 60 ℃. Subsequently, this was also referred to as 80/20 2,4- / 2,6-dorirene diisocyanate (hereinafter referred to as TDI). 5 parts were further added and reacted for 2 hours.

In the above reaction, the NCO / OH was about 2.55.

As a result, a prepolymer containing NCO at both ends was obtained, and the concentration of NCO group was 4.33%.

Next, 100 parts by weight of ethylene oxide (molecular weight about 3,000, OH value 55.4) was reacted with 100 parts of the prepolymer obtained by polymerizing ethylene oxide at the terminal of the polyoxypropylene triol as a curing agent.

In this case, in order to improve the mixing efficiency or to meet the specifications of the commercially available injector, dioctylphthalate is added as a plasticizer to the prepolomer and the curing agent, and the mixing ratio is mixed at 1: 1 by volume ratio and stirred, and the pump is 1,300R-20. Filled into a tire of the size of. At this time, the ratio of the NCO group in the prepolymer to the OH group in the curing agent and the NCO / OH were 1.03.

After the filling was cured, the obtained tire was pressed into a drum having a smooth diameter of 1.6 m under a load of 300 kg and subjected to an endurance test under the same driving conditions with an ambient temperature of 35 ° C. and a speed of 60 km / hr. The results are shown in Table 2.

On the other hand, the filler was cured separately without filling the tire to measure hardness and resilience.

The results are shown in Table 2 together.

TABLE 2

Example 3

Liquid polyisopropene containing OH groups at the ends (1,4-trans 60%, 1,4-cis 20%, 1,2-, 3,4-bonds each have a 10% chemical structure and a number average molecular weight of 3,000 , 18.8 parts of diphenylmethane diisocyanate (MDI) was added to 100 parts of OH group content of 0.075 meq / g) and reacted at 60 ° C. for 1 hour in the same manner as in Example 2. Subsequently, 4.4 parts of reylene diisocyanate (TDI) were further added and reacted for 2 hours.

At this time, NCO / OH = 2.70 in the reaction.

As a result, a prepolymer containing NCO was obtained at the sock end, and the concentration of NCO group was 4.26%.

This prepolymer is referred to as X.

On the other hand, 17.5 parts of TDI was added to 100 parts of polyoxypropylene glycol (number average molecular weight 2,000, OH group content 0.1meq / g), and it was made to react at 70 degreeC for 3 hours, and the thing of 3.5% of NCO groups was obtained.

This prepolymer is referred to as Y.

The prepolymer X80 part thus obtained and the prepolymer Y20 part, and 10 parts of ethylene glycol dibenzoate as a plasticizer were added and mixed well in order to improve compatibility and improve workability.

On the other hand, 89 parts of 10 weight% addition polymerization (molecular weight about 3,000, OH group content 0.10meq / g) and 17 parts of the plasticizer mentioned above were added and mixed at the terminal of polyoxypropylene triol as a hardening | curing agent. Subsequently, the above two mixtures were mixed. The volume ratio of the curing agent to the prepolymer was almost 1: 1, and it was able to fill in a 1,300R-20 size tire while mixing with a commercially available pump.

At this time, the ratio NCO / OH of the NCO group in the prepolymer and the OH group of the curing agent is 1.10.

The filling was allowed to stand for 24 hours and cured, and then the obtained tire was pressed into a drum having a smooth diameter of 1.6 m under a load of 3,000 kg, and subjected to endurance test under the same conditions of an ambient temperature of 35 ° C. and a speed of 60 km / hr.

There was no abnormality at more than 10,000 km.

On the other hand, the cured at the same time at the time of injection was 56% at 25 ° C and 87% at 100 ° C, and the prepolymers were separately prepared and bolen, respectively, which were sufficient for this purpose.

Example 4

In the same manner as in Example 1, R45M and TDI were reacted at a ratio of NCO / OH as shown in Table 3 to prepare an NCO terminal prepolymer. R45M was reacted with this prepolymer so that the ratio of NCO / OH was 1.0, and the test tire for filling tire and resilience measurement was obtained.

The results are shown in Table 3.

TABLE 3

NCO/OH

3.0의 범위로 할 필요가 있는 것을 알 수 있다.In Table 3, NCO / OH in the preparation of the prepolymer is greatly affected by the properties of the elastomers obtained, in particular, the resilience.

NCO / OH

It can be seen that it is necessary to set the range to 3.0.

Example 5

Various properties were measured using the same prepolymer obtained in Example 1 and adding R45M as the curing agent to the ratio of NCO / OH shown in Table 4, and the results are shown in Table 4.

TABLE 4

In Table 4, the higher the value of the rebound modulus, the less heat is generated when the stress is repeatedly reduced, and the driving distance is increased when the tires are filled with them.

Example 6

Experiment No. of Example 5 5 parts by weight of graphite having a particle size distribution of 10-20 μ was added to the filler of the same formulation as in 7, and the predetermined test was carried out. The hardness was 31%, the elastic modulus of 54% (25 ° C), 71% (100 ° C), and running. The distance became more than 10,000 km. Although the resilience modulus decreases by mixing graphite, the fact that the traveling distance as a tire exceeds 10,000 km is thought to suppress local heat generation by incorporating graphite.

Example 7

Table 5 shows the properties of the packings obtained by the combination of various polymers using diene polymers.

In addition, the curing method of the polyurethaneurea elastomer was carried out in the same manner as in Example 1.

TABLE 5

1) Dissipation amount.

2) amino terminal butadiene-acrylonitrile copolymer.

3) OH group terminal polyfunctional Mw 2,800 OH group terminal polymer obtained by adding ethylene glycol to polybutadiene.

4) Units of numbers represent parts by weight.

In Table 5, prepolymer P is the same prepolymer as used in Example 1, and prepolymer Q is 2,4 to the diene-ether polymer obtained by adding ethylene oxide to both ends of the liquid polybutadiene of Mw 2,00. It is a prepolymer of 6% isocyanate content obtained by reacting -TDI.

In addition, the tire of the filling material of the Example shown in Table 5 was not changed even after the driving test of 10,000 km or more.

Example 8

The properties of the packing obtained by the combination of the diene polymer and the polymer using the polyoxyalkylene polymer are shown in Table 7.

In addition, the curing method of the polyurethane elastomer and the manufacturing method of the prepolymer were the same as in Example 2, but the amount of the liquid polybutadiene and polyoxypropylene glycol was changed.

Table 6 shows a compounding example at the time of preparing the prepolymer.

As is apparent from Table 6, Experiment No. 923 has a viscosity of 14,000 CPS at 30 ° C. when the prepolymer was prepared using TDI.

However, No. In 20-22, although MDI is used, polyalkylene polyol is added to form a prepolymer, so that the viscosity decreases and tire filling workability becomes easy, and stable quality is obtained. The amount of the polyalkylene polyol is preferably 100 parts to 5 parts based on 100 parts of the polyol having a diene structure.

TABLE 6

TABLE 7

Note 1) Polyoxypropylgen glycol with molecular weight of 1,000

2) amino group terminal butadiene-acrylonitrile copolymer ATBN 1,300 × 16 BFG

3) R-45HT

4) Addition polymerization of ethylene oxide to R-45HT, containing OH group 0.07meq / g

5) OH group content of polyisoprene Japanese Patent Publication No. 1075-30103 0.075 meq / g Number average molecular weight about 3,000.

In Table 7, prepolymer R is the experiment No. Prepolymer S obtained in 21 and Prepolymer S are 20 parts of a polyoxypropylene glycol (molecular weight 2,000) blended into a diene-ether polymer obtained by adding ethylene oxide to both ends of a liquid polybutadiene having a number average molecular weight of 2,800, and 24 -TDI is reacted to a prepolymer having an isocyanate content of 6.2%.

The tires filled with the fillers of the examples shown in Table 7 were not abnormal even after the driving test of 1,000 km or more.

Claims (1)

At least at the terminal is a prepolymer (A) having an isocyanate group at the terminal obtained by reacting a polymer (C) containing a diene polymer having a molecular weight of 10,000 or less and a diisocyanate compound at a ratio of the following range (II). The elastic tire filler composition obtained by reacting the hardening | curing agent (B) which consists of a compound which has a hydroxyl group or an amino group in the ratio of the following range (I). (I): 0.7

1.3 (II): 1.6

3.0