JPS6021641B2 - Production method of liquid polyisoprene rubber derivative with excellent storage stability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a liquid polyisoprene rubber derivative having excellent storage stability.

Recently, liquid polyisoprene rubber has attracted attention as a new material, and its liquid state, tackiness, and high plasticizing effect are used for plasticizer applications, and its double bond is used for sulfur-carrying, It is used as a solid rubber or semi-solid rubber by crosslinking it into a polymer by crosslinking means such as peroxide vulcanization or radiation crosslinking.

However, as another requirement, liquid polyisoprene rubber having a reactive trough group in its molecule is attracting attention because of its advantage in that it can undergo a crosslinking reaction using its polar groups. The present inventors investigated the possibility of reacting maleic anhydride as a method of introducing polar groups into liquid polyisoprene rubber, and succeeded in introducing maleic anhydride. It has been found that it cannot be used as a liquid rubber in practice because of the disadvantage that it cannot maintain its liquid rubber form. Therefore, the present inventors investigated various methods for producing liquid polysoprene rubber derivatives with excellent storage stability, and found that by reacting with maleic anhydride and then treating with a specific alcohol and/or amine compound. It was discovered that a liquid polyisoprene rubber derivative having excellent storage stability can be obtained, leading to the present invention.

That is, according to the method of the present invention, the above-mentioned purpose is achieved by reacting hydrothermal maleic acid with a liquid polyisoprene rubber having a viscosity average molecular weight of 8,000 to 77,000 and a cis-1,4 content of 75% or more. At least 0.03 to 10 mol % of the liquid polyisoprene rubber derivative is added to the isoprene monomer unit of the liquid polyisoprene rubber, and the general formula R,
Alcohols represented by 1OH (R represents an alkyl group having 1 to 10 carbon atoms, an aralkyl group, or an organic residue containing an ether bond or an amide/bond in the molecule), especially methyl alcohol or isopropyl Alcohol and/or an amino compound represented by the general formula (R2 and R3 represent hydrogen or an alkyl group having 1 to 10 carbon atoms, an allyl group, or an aralkyl group, and may be the same or different). I saw what could be achieved by letting it be processed, and I put it out there.

The liquid polyisoprene rubber used in the present invention has a viscosity average molecular weight of 8,000 to 77,000, preferably 15,000.
It is a high cis-1,4-polyisoprene low polymer with a cis-1,4 content of 75% or more and has fluidity at room temperature.

If the molecular weight is low, the physical properties will be poor even if crosslinked, and if the molecular weight is too high, the fluidity will be low and it will not have the characteristics of a liquid rubber. Furthermore, those with a low cis-1,4-content of less than 75% have poor physical properties after crosslinking and need to be at least 75%. Viscosity average molecular weight (M) is 30 in toluene
The intrinsic viscosity was determined by the following formula by measuring the intrinsic viscosity measured at 00.

[Ri]: 1.21XIO-4×Fude. 77cis1,4-
The content can also be determined by infrared spectroscopy.

If the reaction between liquid polyisoprene rubber and maleic anhydride is simply a reaction, a known method can be used, but in order to obtain a product in which the reaction product remains in a liquid state, It is important to suppress the gelation reaction that progresses as a side reaction during the reaction.

In other words, the most preferable conditions are 12 to 250 degrees Celsius, preferably 140 to 250 degrees Celsius, without using a radical generating catalyst.
The reaction is carried out by heating at 200 qo. Although it is possible to carry out the reaction using a radical-generating catalyst, it is important to use an appropriate amount so that the gelation reaction does not proceed so much and the maleic anhydride addition reaction proceeds sufficiently. For example, in the case of penzoyl peroxide, less than 0.1 ta per 100 parts of liquid polyisoprene rubber is used and the reaction is performed at 80 to 12 pi. Further, it is possible to use di-tertiary-butyl peroxide at 140 to 18 pi by using 0.1 ta or less per 100 of the liquid rubber. The term "radical generating catalyst" refers to a compound that is decomposed by heating or using a reducing agent to generate active radicals, and is used as a catalyst in normal radical polymerization and radical reactions.

That is, peroxides such as penzoyl peroxide, lauroyl peroxide, and cumene hydroperoxide, and hydroperoxides, 2,Z-azobisisobutyronitrile, 2,2-azobis(4-methoxy-2,
Azo type catalysts such as 4-divaleronitrile) and redox type catalysts such as cumene hydroperoxide amine type can be used, but peroxides are most suitable. Although the reaction can be carried out in the substantial absence of a solvent, a solvent can be used to reduce the viscosity of the reaction system and facilitate temperature control.

There are no limitations on the suitable solvent as long as it does not react with maleic anhydride and can dissolve or disperse the liquid polymer. For example, aliphatic hydrocarbons such as butane, bentane, hexane, and heptane, alicyclic hydrocarbons such as cyclohexane and decahydronaphthalene, aromatic hydrocarbons such as benzene, toluene, xylene, and naphthalene, and halogens such as chloroform and carbon tetrachloride. Hydrocarbons, etc. alone or in mixtures are suitable. The reaction temperature can be set depending on the presence or absence of a radical generating catalyst used and the decomposition temperature of the catalyst, but is preferably 60°C to 25°C.
0qo, preferably 100°C to 200°C.

A higher temperature is preferable because gelation during the reaction can be suppressed. However, at a high temperature of 25,000° C. or higher, coloration due to decomposition of the rubber during the reaction is significant and undesirable. The reaction time is appropriately determined depending on the reaction temperature, the type of catalyst, etc., but is usually 10 minutes to 1 hour, preferably 30 minutes to 5 hours.

A liquid polyisoprene rubber derivative obtained by adding 0.03 to 10 mol% of maleic anhydride to the isoprene monomer unit of the liquid polyisoprene rubber obtained by the above method. By subjecting the material to a catalytic reaction treatment with an alcohol and/or amine compound, storage stability is improved.

The preferred amount of maleic anhydride to be added is 0.03 to 10 mol %, more preferably 0.1 to 4 mol %, and if it deviates from this range, the original purpose of the present invention will not be achieved. Compounds represented by the general formula 1OH include methyl alcohol, ethyl alcohol, and OH. ○ Pyl alcohol, inpropyl alcohol, butyl alcohol, secondary butyl alcohol, tertiary butyl alcohol,
Aliphatic alkyl alcohols such as isoamyl alcohol, octyl alcohol, nonyl alcohol, or alicyclic alkyl alcohols such as cyclohexyl alcohol,
In addition to ararykyl alcohols such as penzyl alcohol, cellosolves such as 3-methyl-3'-methoxybutanol and butoxyethyl alcohol (butyl cellosolve), dimethylaminoethanol, and the like. Among these, primary or secondary alcohols such as lower aliphatic alkyl alcohols such as methyl alcohol and inpropyl alcohol are advantageous because they have high reactivity and can be easily removed by heating when removing the reaction alcohol in post-treatment. .
Examples of compounds represented by are alkylamines such as dimethylamine, dibutylamine and diisopropylamine, allylamines such as diphenylamine, aralylamines such as dibenzylamine, and ammonia.

Alcohol is more preferable because the liquid polyisoprene rubber derivative, which is the object of the present invention, has better storage stability and the chemicals used are less toxic.

The reaction between maleic anhydride-added liquid polyisoprene rubber and alcohol and/or amine compound is 50-200%
This is achieved by heating at qo.

In this reaction, there is no problem even if unreacted maleic anhydride coexists in the reaction system, and the presence of a reaction solvent is not necessarily required. If it is less than 50 qo, the treatment effect will be low, and if it exceeds 20 qo, the polymer will decompose, which is not preferable.

Although the heating time can be arbitrarily changed depending on the reaction conditions, it is desirably 5 minutes or more, preferably 20 minutes or more. After the reaction, the liquid polymer is preferably extracted and removed with a solvent such as water or acetone that does not dissolve the liquid polymer and dissolves alcohol, amine, maleic anhydride, and its enigmatic conductor, and then dried. However, it is also possible to directly heat the reacted polymer to evaporate the alcohol, amine and unreacted maleic anhydride and its derivatives. The heating temperature during drying is quite important, and it is desirable to avoid increasing the temperature too high.

For example, room temperature to 180 OO, preferably 50 to 15 pi, is desirable; if the temperature is too high, the storage stability will decrease. The liquid polyisoprene rubber derivative with excellent storage stability obtained according to the present invention can be used as it is in combination with ordinary rubbers, plastics, etc. as plasticizers, softeners, thickeners, sealants and adhesives.

In addition, by cross-linking reaction using the introduced gutter functional group, by polymerizing by cross-linking reaction with the functional group and a suitable cross-linking agent, it is possible to use solid rubber, semi-solid rubber, etc. Used for rubber molded products, sealants, adhesive base polymers, etc. In addition, since the liquid polyisoprene rubber derivative obtained by the present invention has a large number of double bonds in its main chain, it cannot be used with vulcanizing agents, vulcanization accelerators, etc. normally used in the rubber industry. It is possible to add a crosslinking agent as well as ordinary rubber stabilizers such as ordinary anti-aging agents and ultraviolet absorbers.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples in any way.

In the examples, parts mean parts by weight unless otherwise specified. Example 1 10 anchor parts of liquid polyisoprene rubber with a viscosity average molecular weight of 30,000 obtained by polymerizing isoprene monomer using secondary butyl lithium as a catalyst were added with 5 parts of maleic anhydride under a nitrogen gas atmosphere. The mixture was heated and reacted at 160°C for 2 hours.

After cooling, the reaction product was thoroughly washed with acetone to remove unreacted maleic anhydride, and then vacuum-dried at 5,000 °C overnight. As a result of analysis using an infrared spectrophotometer, maleic anhydride groups were found to be 1.
It was found that 0 mol% was added. 10 parts of this maleic anhydride-added liquid isoprene rubber was dissolved in 10 parts of toluene, 2 parts of methanol was added, and the mixture was treated at 100 qo for 2 hours. This treated product was poured into a large amount of acetone, toluene and excess methanol were extracted and removed, and then 0.00% of the anti-aging agent 2,6-di (tertiary butyl) para-cresol was added.
A liquid polyisoprene rubber derivative (A) was obtained by adding Yuho and vacuum drying at 60°C overnight. On the other hand, for comparison, a liquid polyisoprene rubber derivative (B) was obtained which was treated under the same conditions except that it was not subjected to the reaction treatment with ethanol. Conductor (A
) showed almost no change in viscosity even after being left in air for 30 days, and was found to have fluidity at room temperature and good storage stability.

On the other hand, it was found that when the derivative (B) was left in the air for 30 days, it gelled and ceased to flow at room temperature.

From this, the maleic anhydride-added liquid polysophylamide resin having excellent storage stability can be obtained by methanol treatment according to the present invention. It is understood that the rubber derivatives can be obtained. Note that the derivative (A
) was mixed with zinc oxide at 120° C. for 2 minutes and molded. A solid rubber was obtained, and it was confirmed that metal crosslinking was possible by the carboxy group of the functional group. Example 2 4 parts of isopropanol instead of 2 parts of methanol in Example 1
The treatment was carried out under the same conditions as in Example 1, except that 10% of the sample was used.

The obtained liquid polyisoprene rubber derivative had good storage stability with almost no increase in viscosity observed even after being left in the atmosphere at room temperature for 50 days. Example 3 The same conditions as in Example 1 were carried out except that 1 part of pendyl alcohol was used instead of 2 parts of methanol in Example 1.

The obtained liquid polyisoprene rubber derivative was left in the atmosphere at room temperature for 30 days, but almost no thickening was observed and it had excellent storage stability. Example 4 10 liquid polyisoprene rubber having a viscosity average molecular weight of 45,000 obtained by low-polymerizing isoprene monomer using a lithium catalyst was prepared by adding 3 parts of maleic anhydride to it under a nitrogen atmosphere.
The reaction was carried out by heating at 80 qo for 1 hour.

After the reaction solution was cooled to 12,000 ℃, 3 parts of ethanol was added thereto, and the mixture was heated for another 1 hour. After cooling the reaction solution, 100 parts of water was added thereto, left to stand for 30 minutes, and the aqueous layer was separated and removed three times to remove the reactant by washing and extracting with water. The anti-aging agent 2,2'-methylenebis(4-methyl-
After adding and mixing 0.05 part of 6-tert-butylphenol as a hexane solution, the mixture was heated and dried under reduced pressure at 100 qo for 3 hours. The liquid polyisoprene rubber conductor thus obtained remained liquid with almost no increase in viscosity even after being left in air at room temperature for 50 days. Example 5 High-cis synthetic polyisoprene rubber (viscosity average molecular weight = 75
Viscosity average molecular weight 5 obtained by thermally decomposing 1,400,000 psi (total amount 97%) in a nitrogen stream at 300 pm for 1 hour.
100 parts of liquid polyisoprene rubber of 0.000% was mixed and dissolved with 20% of xylene.

1.5 parts of maleic anhydride and 0.03 parts of di-tert-butyl peroxide were added to this solution, and
The mixture was heated and reacted at 0 for 1 hour. After the reaction is completed, the reaction solution is heated to 100o
3 parts of methanol was added and the mixture was reacted for 1 hour. After cooling, the reaction solution was washed with a large amount of methanol, and the anti-aging agent 61 (4-hydroxy-3,5-di-tarsialbutylanilino)1, 2,4-bis-octylthiol1,
After adding 0.05 part of 3,5 triazine (Irganox 565, manufactured by Ciba Geigy), the liquid polyisoprene rubber conductor was vacuum dried at 60 DEG C. overnight. The obtained liquid polyisoprene rubber derivative was left in the atmosphere for 30 days, but there was almost no thickening and the storage stability was good. On the other hand, for comparison, a maleic anhydride-treated liquid polyisoprene rubber derivative obtained under the same conditions as in the example except that methanol was not added and the heating reaction was not carried out was cured when left in the atmosphere for 30 days, and ceased to be a liquid rubber. Stability was poor.

From this fact, it was confirmed that the storage stability is improved by subjecting the maleic anhydride-added liquid polyisoprene rubber to a heating reaction with methanol.

Example 6 The same conditions as in Example 1 were used except that 2.5 parts of diisoptylamine was used instead of methanol.

The obtained liquid polyisoprene rubber derivative was left in the air for 20 days, but it remained liquid and did not harden.
Example 7. The treatment was carried out under the same conditions as in Example 1 except that 0.5 part of ammonia was used instead of methanol.

Claims (1)

[Scope of Claims] 1 A liquid polyisoprene rubber having a viscosity average molecular weight of 8,000 to 77,000 and a cis-1,4 content of 75% or more is reacted with maleic anhydride to form the liquid polyisoprene rubber. An alcohol represented by the following general formula (1) and/or an amine compound represented by the general formula (2) is added to a liquid polyisoprene rubber derivative in an amount of 0.03 to 10 mol% based on the isoprene monomer unit of the isoprene rubber. 1. A method for producing a liquid polyisoprene rubber derivative with excellent storage stability, characterized by subjecting it to a reaction treatment. (1) R_1-OH (R_1 represents an alkyl group having 1 to 10 carbon atoms, an ararykyl group, or an organic residue containing an ether bond or an amino bond in the molecule) ▲ Formula,
There are chemical formulas, tables, etc. ▼ (R_2 and R_3 represent hydrogen or an alkyl group having 1 to 10 carbon atoms, an allyl group, or an alkyl group, and may be the same or different)