JPS5818245B2 - tire filling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tire filling material, and more particularly to a urethane-based tire filling material having excellent resilience and appropriate hardness.

So-called elastic tires, which are tires filled with an elastic material, have better load carrying capacity than pneumatic tires, and there is no risk of punctures, so they are expected to be used as tires for public vehicles such as buses and subways.

In particular, when using urethane-based polymer as a filler, a method is used in which liquid prepolymer is injected into the cavity of a tire with a rim assembled in advance and reacted with the polymer of appropriate hardness within the tire. It has the advantage of being easy to construct.

Conventionally used urethane-based elastomers include hydroxyl group (hereinafter referred to as OH group)-terminated polyether or OH group.
It was an elastic body obtained from a group-terminated polyester and a diisocyanate, that is, a polyurethane having a polyether or polyester skeleton.

For example, 'TYRFIL'' (trademark of 5ynair) is said to be a reaction product of a mixture of polyoxypropylene glycol and polyoxypropylene triol and tolylene diisocyanate (hereinafter abbreviated as TDI).

However, such conventional urethane-based elastic bodies have the following drawbacks.

(1) Tire fillings are required to have a high resilience modulus and appropriate hardness, but with conventional urethane-based elastomers, if the resilience is increased, the hardness becomes too high, and if the hardness is decreased, the resilience becomes low. Put it away.

(2) When filled into a tire and subjected to repeated strain under load, the urethane elastic body generates heat within the tire, becomes unable to withstand stress, crumbles, deteriorates, and melts. Impairing the given elasticity and spring constant.

As a way to improve these problems, for example, we determined that the reason for the deterioration of the urethane elastic body is that the amine-based anti-aging agent contained in tire rubber migrates to the urethane side, and we created a halogenated material between the elastic body and the rubber. A method of forming a layer of butyl or a rubber containing it has been proposed, but it has not been an essential solution.

As a result of intensive studies, the inventors of the present invention have developed the following invention in order to solve the above-mentioned drawbacks of the conventional technology, reduce heat generation of tires during driving, and improve ride comfort and driving durability of the vehicle. reached.

That is, the present invention has a hydroxyl group at the end and a molecular weight of 100.
A terminal isocyanate prepolymer (A) obtained by reacting a diene polymer of 00 or less and a diisocyanate compound at a ratio satisfying the following range, and a curing agent (B) having a hydroxyl group or an amino group at the terminal. This tire filling is characterized by being made of an elastomer obtained by reacting at a ratio that satisfies the above range.

The diene polymer used in the present invention has OH groups at both ends of the side chain. For example, it is a liquid or semisolid polymer obtained by polymerizing C4 to C5 conjugated diene monomers, and has OH groups at both ends of the side chain. The introduction method is Special Publick 50-3010
3. The method according to Publication No. 50-30104, the method of polymerizing using an organometallic catalyst such as alkyl Li as an initiator and ethylene oxide etc. as a stopper, the method using a cutting agent containing an OH group, or the method of oxidizing a normal diene polymer. Any method may be used, such as attaching an OH group to the cut side chain.

In addition to diene monomers, vinyl compounds such as styrene, acrylate, acrylic acid, and acrylic esters can also be used in a proportion of less than 30 parts per 100 parts of the diene monomer.

Such a diene polymer of the present invention needs to have OH at both ends, and has a molecular weight of 100.

Must be less than or equal to

If the molecular weight is too high, the viscosity of the prepolymer produced by reacting it with a diisocyanate will be high, making the filling operation difficult.

As the diisocyanate, hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,
472, 6-tolylene diisocyanate) (80/2
0 or 65/35), xylylene diisocyanate, tolidine diisocyanate, 4,4'-diphenylmethane diisocyanate, phenylene diisocyanate (
m+ p) methylenebis(2-methyl p-phenylene) diisocyanate, 3,3'-dimethoxy4
, 4'-biphenylene diisocyanate, 3,3'-dimethyl 4,4-diphenylmethane diisocyanate, inphorone diisocyanate, etc., or a mixture thereof can be used.

When reacting such a diene polymer and a diisocyanate, the stoichiometric ratio (NCOloH) between the NCO group in the diisocyanate and the OH group of the diene polymer is 1.6.
It is necessary to keep it in the range of ~3.0.

If NC010H is smaller than 1.6, the molecular weight of the obtained prepolymer will become too large and the viscosity will increase.
It is unsuitable for filling tires.

Furthermore, if NC010H exceeds 3.0, the viscosity decreases, but it is difficult to control the reaction, and since the molecular weight of the prepolymer decreases, the urethane bond density in the final polymer increases, resulting in an increase in hardness.

Therefore, at the stage of making prepolymer, NC010
It is necessary to set H to 1.6-3°0.

In the present invention, the NCO-terminated prepolymer obtained as described above is injected into a tire together with a curing agent and cured.

The curing agent is a compound having an OH group or an amine group at the end, and the following compounds are used.

OH group-terminated diene polymer used in producing the prepolymer, preferably 10 moles or less of PH group-terminated diene type t' IJ mama-ethylene oxide or propylene oxide, polyether polyol, 1. 4-butanediol, trimethylolpropane, 1,6-hexanediol, glycerin, castor oil,
Relatively low molecular weight polyols such as diethylene glycol, OH group-containing vegetable oils, polyalkylene oxides with terminal amine groups (e.g. Jefferson Chem tc
Jefferamin D-2000 manufactured by
, amine-terminated acrylonide, IJ-lubutadiene copolymer (e.g. ATB manufactured by BFGoorich Chem)
N1300X16) or a mixture thereof.

The reaction ratio between the prepolymer and the above curing agent is NC010H
Alternatively, NH2 needs to be 0.7 to 1.3, preferably 0.8 to 1.15.

Since the prepolymer of the present invention has NCO groups at both ends, by measuring the molecular weight of the prepolymer,
The amount of O can be calculated.

NCO groups in the prepolymer and OH or NH in the curing agent
, O ratio of less than 0.7, curing is slow and the physical properties of the resulting cured product, especially elongation, are poor.

On the other hand, if it exceeds 1.3, the physical properties of the cured product will change over time, and both elongation and tensile strength will deteriorate.

Since the polyurethane of the present invention obtained in this way uses a diene polymer in its skeleton, it has extremely high rebound resilience compared to the polyether or polyester polyurethane used for conventional tire filling. Can maintain hardness.

The reason for this is believed to be that diene polymers have a smaller dynamic loss than polyethers or polyesters.

The tire filling material of the present invention preferably has the following physical properties.

That is, the hardness according to JIS is 15 to 45 degrees (25-4℃)
Big and rebound elasticity (Lübke rebound elasticity) is 25'C50%
As mentioned above, it is necessary that the coefficient is 70 or more at 100°C.

The hardness is related to the deflection of the tire under load. For example, if the hardness is less than 15 degrees, the amount of tire deflection is large, which tends to generate heat during running and cause the filling to melt.

Moreover, if the hardness exceeds 45 degrees, the cushioning effect will be reduced and the riding comfort of the vehicle will be deteriorated, which is not preferable.

The higher the value of rebound elasticity, the more rapid recovery from strain occurs, and the smaller the heat accumulation due to deformation and strain, which is preferable, but it is practically sufficient if it is 50% or more at 25°C and 70% or more at 100°C.

In order to preferably form the tire filling of the present invention in a tire, it is preferred that the mixture of prepolymer and curing agent to be injected into the tire has an appropriate viscosity1, at least a viscosity at 10'-50°C should be less than 100 poise.

This is because if the viscosity is too high, it will be difficult to press into the tire, and if the viscosity is lowered to the outer edge, the reaction speed will increase, which is not preferable.

For example, when injecting into a 1000R-20 size tire, it usually takes about 40 minutes to 2 hours, so it is necessary to use a prepolymer with a low viscosity in advance, taking into account the increase in viscosity caused by the reaction during this time.

Of course, this viscosity concerns the viscosity just before it is injected into the tire, and even if the viscosity of the original polymer is high,
Although it is possible to lower the viscosity by mixing these or by mixing a plasticizer described below, it is necessary to use a diene polymer with a molecular weight of 10,000 or less.

It is necessary to select a plasticizer that has good compatibility with the final polymer, such as aliphatic dicarboxylic acid esters, aromatic dicarboxylic acid esters, glycol esters of monocarboxylic acids, process oils for rubber, pine cool, polybutene, and inert liquids. Polymers and the like are preferred; however, if used in large quantities, the rebound properties will be reduced, so the amount should be 100 parts or less, preferably 50 parts or less, based on 100 parts of the polymer.

Injected into the tire for the purpose of quickly curing the above mixture, catalysts for the urethanization reaction, such as tertiary amines such as triethylenediamine, triethylenetetramine, or amino alcohols, 198-diazabicyclo(594
90) Undecene-7 and its salts, imidazoles, organic Sn compounds, organic Fe compounds, etc. can be used.

The amount of these catalysts is based on 100 parts of prepolymer.
It is preferably 0.1 part or less.

In addition, graphite, carbon blank, clay, tar, silica, etc. can be used as fillers, but if these are added in large quantities, the hardness will increase and the rebound resilience will decrease, so 100 parts of polymer The amount is preferably 10 parts or less.

It is thought that the effect of fillers is to suppress local heat generation, but in the case of graphite, for example, if the particle size is 150 parts or more, a foreign body effect will occur, and dynamic fatigue will be extremely poor. The diameter should be less than 150μ.

The present invention will be specifically explained below with reference to Examples.

Note that the physical properties described in Examples and Comparative Examples are based on the following test methods.

Hardness JIS (degree) JIS K6301
JIS K6301 Example 1 Liquid polybutadiene with OH at the end (1°4-trans 60%, 1,4-cis 20%, 1°2-vinyl 20%)
% chemical structure, number average molecular weight 2700-3000
) R45M (manufactured by Arco Chemical) 8 in 100 parts
0720 2.4-/2,6-1 lylene diisocyanate (hereinafter referred to as T
DI) was added into a reaction vessel equipped with a stirrer and filled with inert gas (dry N2).
The reaction was carried out at 60°C for 8 hours.

The NC010H in this reaction is approximately 2.36.

As a result, a prepolymer having NCO groups at both ends was obtained.

Next, to 100 parts of the obtained prepolymer, 111 parts of the above R45M as a curing agent, 20 parts of dioctyl phthalate as a plasticizer, and 0.046 parts of lead octylate as a catalyst.
After adding 100 parts of the mixture and mechanically mixing well, the mixture was filled into a 1000R20 tire using a pump.

At this time, the NCO group in the prepolymer and the OH in the curing agent
The group ratio NC010H is 1.13.

In addition, the semi-cured urethane resin obtained in the same manner was cast into the mold of a sample for measuring Lübcke's resilience modulus, and cured under the same curing conditions as tires, and the hardness and resilience of the resulting cured product were measured. The results are shown in Table 1.

Comparative Example 1 Polyoxypropylene triol (Mwlooo) 10
0 part and 2 of 80/20, 4-/2, 6-TDI60
(NC010H=2.3), molecular weight 15
Ten terminal NCO prepolymers were obtained.

230 parts of polyoxypropylene glycol (Mw 2000) was mixed with 100 parts of this prepolymer (NC010H=1.0), and the mixture was filled into a tire in the same manner as in the example.

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

* Melted and unable to drive From Table 1, it can be seen that although the hardness is the same, the filling of the present invention has a better rebound modulus, so the tire can run longer.

Comparative Example 2 100 parts of the same prepolymer as in Comparative Example 1 was mixed with 1 part of polyoxypropylene glycol (Mwlooo) as a curing agent.
The mixture of 21 parts (NC010H=0.95) has a hardness of 48 degrees, a resistance elasticity of 60% (at 25°C), and an 85 inch (100
℃), but when used as a tire, the temperature was 2000K.
After traveling for m, the filling cracked and the vehicle became unable to travel.

Example 2 In the same manner as in Example 1, R45M and TDI were reacted so that the ratio of NC010H as shown in Table 2 was obtained, and NCO
A terminal prepolymer was prepared.

The ratio of NC010H to this prepolymer was 1.0.
R45M was reacted to obtain a filled tire and a test sample for measuring impact resilience.

The results are shown in Table 2.

Table 2 shows that NC010H during prepolymer production greatly affects the properties of the obtained elastomer, especially the rebound elasticity.1.
It can be seen that the range needs to be 6≦NC010H43,0.

Example 3 Using the same prepolymer as that obtained in Example 1, and using R45M as a curing agent, NC010 was prepared as shown in Table 3.
The cutting edge sharpening and various properties were measured to achieve the ratio of H, and the results are shown in Table 3.

From Table 3, it can be seen that tires with higher values of rebound modulus generate less heat when subjected to repeated stress, and when tires are filled with them and run, the distance traveled becomes longer.

Example 4 A filler with the same composition as Experimental Shop 7 in Example 3 had a particle size distribution of 10.
When 5 parts by weight of ~20μ graphite was added and a prescribed test was conducted, the hardness was 31 degrees and the rebound modulus was 54 (2
5℃), 71 section (100℃) mileage 10010000
It became higher than k.

By incorporating graphite, although the rebound modulus decreased, the mileage as a tire was reduced to 11%.
The reason why the temperature exceeded 0000k is probably because local heat generation was suppressed by mixing graphite.

Example 5 Table 4 shows the properties of fillers obtained by combining various polymers.

The method for curing the polyurethane urea elastomer is the same as in Example 1.

In Table 4, prepolymer A is the same prepolymer as that used in Example 1, and prepolymer B is Mn
This prepolymer has an incyanate content of 6 and is obtained by reacting 2,4-TDI with a diene-ether type polymer obtained by adding ethylene oxide to both ends of liquid polybutadiene 2800.

Furthermore, all of the tires filled with the fillers of the examples shown in Table 4 showed no change even after running tests of 110,000 km or more.

Claims (1)

[Claims] 1. A terminal inocyanate prepolymer (A) obtained by reacting a diene polymer having a hydroxyl group at the terminal and having a molecular weight of 10,000 or less and a diisocyanate compound in a proportion satisfying the following range; 1. A tire filling material comprising an elastomer obtained by reacting a curing agent (B) consisting of a compound having a hydroxyl group or an amino group at a terminal in a proportion satisfying the following range.