JPH01149802A - Hydrogenation of hydroxyl group-containing conjugated diene polymer - Google Patents

Abstract

PURPOSE:To carry out hydrogenation of a conjugated diene polymer essentially without causing the breakage and elimination of hydroxyl group at an extremely high hydrogenation ratio, by hydrogenating a hydroxyl group-containing conjugated diene polymer using reduced nickel as a catalyst and an ether solvent as a reaction solvent. CONSTITUTION:In the catalytic hydrogenation of a hydroxyl group-containing conjugated diene polymer (e.g., polyisoprene, polybutadiene or polychloroprene), a reduced nickel (preferably obtained by supporting 30-50wt.% of reduced nickel on a carrier such as carbon, alumina, silica or diatomaceous earth) as a catalyst and using an ether solvent (e.g., tetrahydrofuran or dioxane) or a mixture of an ether solvent and a hydrocarbon solvent as the reaction solvent. The process is especially suitable for the production of a polyurethane by reacting the hydroxyl group-containing polymer with a diisocyanate compound.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for hydrogenating a conjugated diene polymer containing a hydroxyl group, and more particularly, to a method for hydrogenating a diene polymer having a hydroxyl group at the end. The present invention relates to a method that has a high hydrogenation rate and can prevent cleavage or separation of hydroxyl groups.

The polymer degenerate product produced by this reaction system is particularly suitable for producing polyurethane by reacting the hydroxyl-functionalized polymer with a diisocyanate compound.

(Prior art and problems to be solved by the invention) Hydroxyl group-containing conjugated diene polymers, especially polyisoprene, polybutadiene, or polychloroprene, which have a hydroxyl group at the molecular end, have distinctive properties as raw materials for polyurethane, etc. There is. However, this polyurethane has poor weather resistance and heat resistance due to the unsaturated bonds present in the conjugated diene polymer. For the purpose of improving weather resistance and heat resistance, unsaturated bonds are generally hydrogenated in the presence of a catalyst.

As hydrogenation catalysts used in such hydrogenation reactions, catalysts in which di-, chelate, palladium, ruthenium or rhodium is supported on a carrier such as silica, alumina or diatomaceous material are known.

However, nickel and palladium catalysts have a low hydrogenation rate of polymers, while ruthenium and rhodium have the problem of causing hydroxyl group cleavage reactions in polymers.

An object of the present invention is to solve such conventional problems and provide a method capable of hydrogenating a hydroxyl group-containing conjugated diene copolymer at a high hydrogenation rate without cutting or eliminating hydroxyl groups. .

(Means for Solving the Problems) The present inventors have made efforts to develop a reaction method that has a high hydrogenation rate and does not cause hydroxyl group scission during hydrogenation as a hydrogenation method for a hydroxyl group-containing conjugated diene polymer. As a result of repeated research,
By using a so-called reduced nickel catalyst and using an ether organic solvent or a mixed solvent of an ether organic solvent and a hydrocarbon organic solvent as the solvent during hydrogenation,
The present invention was achieved based on the discovery that the hydrogenation rate is high, the hydrogenation rate is high, and hydroxyl group scission does not occur.

That is, the gist of the present invention is to hydrogenate a hydroxyl group-containing conjugated diene polymer, use a reduced nickel catalyst, and use an ether organic solvent or an ether organic solvent and carbonization as a solvent during hydrogenation. The purpose is to use a mixed solvent of water and organic solvent.

The "hydroxyl group-containing conjugated diene polymer" to which the hydrogenation method of the present invention is applied refers to a conjugated diene polymer having a hydroxyl group in the molecule, such as 1,3-butadiene, 1,3
- It is a polymer produced by a known method using monomers such as pentadiene, isoprene, 2,3-dimethylbutadiene, and phenylbutadiene as raw materials. In addition, in addition to the above-mentioned homopolymers of conjugated diene monomers, copolymers of two or more conjugated diene monomers and copolymers of conjugated diene monomers and vinyl monomers can also be used in this reaction. can. When two or more conjugated diene monomers are copolymerized, the ratio between each component is not particularly limited and may be arbitrary. The above vinyl comonomers include, for example, styrene, vinyltoluene, alphamethylstyrene, vinylnaphthalene, coumaronindene, vinylpyridine, vinylfuran, acrylonitrile, ethyl acrylate, methyl acrylate, methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylic acid. , methacrylic acid and the like. Such comonomers are used in an amount of not more than 95, preferably not more than 80, by weight of the total monomers.

Furthermore, as the number of hydroxyl groups contained in the "hydroxyl group-containing conjugated diene polymer" used here increases, the hydroxyl groups are more likely to be cut off by the hydrogenation reaction, and the hydrogenation catalyst is often deactivated. The preferred hydroxyl group content is 117 in one polymer molecule.
: 1 or more and 10 or less.

The number average molecular weight (Mn) of the water rR group-containing conjugated diene polymer used in the present invention is preferably in the range of 500 to 50,000, preferably 700 to 30,000. molecular weight is 5
Oligo 97- having a hydrogenated oligomer of 0 or less has the disadvantage that the polyurethane obtained using the hydrogenated oligomer lacks flexibility. In addition, polyurethane made of a hydrogenated conjugated diene polymer containing hydroxyl groups with a molecular weight of 50,000 or more has poor compatibility between hard segments and soft segments, so it has the disadvantage that mechanical strength decreases due to large hard segments. have The number average molecular weight mentioned here is determined by Darnoyarm chromatography (GPC).
) It is the number average molecular weight in terms of polystyrene based on K.

The hydroxyl group-containing conjugated diene polymer used in the present invention can be obtained by various methods. For example, an azobis-based compound having a functional group (for example, β, β'-azobis(β-cyano)-n-prof-nol, δ, δ′-azobis(δ-cyano)-n-
pentanol, etc.], or peroxides (e.g. hydrogen peroxide,
Radical polymerization may be carried out using cyclohexane peroxide, methylcyclohexanone peroxide, etc.) as a catalyst. To specifically describe the experimental method using isoprene as the monomer, hexane 300/- as the solvent,
Isoprene 68y- as a monomer and cy(
= 10 mol of polymer) was placed in a 1 ton autoclave, heated to 80°C with stirring, and polymerized for 20 hours to obtain hydroxyl group-containing polyisoprene (yield: 65%, weight = 5,500, OH value: 2111- ) can be obtained.

The hydroxyl group-containing conjugated diene polymer of the present invention can also be produced by anionically polymerizing the above monomer using an alkali metal such as sodium or lithium as a catalyst, and then adding alkylene oxide, epichlorohydrin, etc. to impart a hydroxyl group.

A specific example using isogrene monomer is as follows: In a 1 ton autoclave, 15 wt% solution of n-butyl lithium was added in a 1 ton autoclave, with 400 hexane as the solvent and 1.3 yt of divinylbenzene as the catalyst raw material [l1lt] kept at -20°C.
After dropping 0/-, the reaction was allowed to proceed for 30 minutes to synthesize a dilithium catalyst. Thereafter, the temperature was raised to -10°C, and isogrene monomer 68) was added dropwise to carry out an anion living reaction. Cypolymer yield was 98 after 2 hours of reaction run-up.
%. After that, ethylene oxide was added to stop the reaction, and by adding drained water, polyethylene (Mn = 7,000, OHHI381'V) with hydroxyl groups added to both ends was added.
l-) can be obtained.

In addition to these methods, there is a method described in JP-A-57-16003, in which maleic anhydride is added to a conjugated diene polymer, and then -tubular H2NRA-O
A hydroxyl group-containing conjugated diene polymer obtained by reacting H (RA is an alkyl group, an aryl group, or an aralkyl group) and then obtaining a heated dehydrated diene polymer may be used.

When the hydroxyl group-containing conjugated diene polymer obtained by these methods is hydrogenated using reduced nickel as a catalyst and an ether solvent or a mixed solvent of an ether solvent and a hydrocarbon solvent as a solvent, it is difficult to hydrogenate. , can be easily hydrogenated at a high K without cutting the hydroxyl group.

The reduced nickel catalyst used in the present invention is supported on a carrier such as carene, alumina, silica, diatomaceous earth, or the like. Alternatively, the original nickel catalyst supported on the same carrier may be 2 to 30% by weight/two fingers with zirconium, an alkali metal, or an alkaline earth metal as a co-catalyst. In any case, the support of reduced nickel on the carrier [20~
It may be within a range of 60% by weight, and more preferably 30 to 50% by weight.

Ether-based organic solvents used in the present invention include chain ethers such as ethyl ether, n-butyl ether, inclovir ether, noisoamyl ether, phenol ethers such as phenyl ether, anisole, phenetol, amyl phenyl ether, tetrahydrofuran, Examples include cyclic ethers such as tetrahydrobilane, dioxane, and trioxane, with cyclic ethers being particularly preferred. Examples of the hydrocarbon organic solvent that can be used in combination with the above ether organic solvent include hexane, heptane, octane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, and the like.

The mixing ratio of the ether organic solvent and the hydrocarbon organic solvent depends on the type of organic solvent used and the target hydrogenation reaction rate. The amount of solvent is 1 to 100 times, preferably 1
0-100! f%.

In the present invention, the temperature during the hydrogenation reaction is usually from room temperature to 2.
Can be arbitrarily selected within the range of 00°C, but preferably 80°C
to 180°C. If the reaction temperature is lower than room temperature, the hydrogenation rate will be too low, and if it exceeds 200°C, the cleavage of hydroxyl groups will become noticeable, which is not preferable.

The hydrogenation rate of the polymer is varied depending on the purpose, but the hydrogenation rate is determined by measuring the iodine number of the polymer before and after hydrogenation to obtain a polymer with a predetermined hydrogenation rate.

The amount of reduced nickel used can be arbitrarily selected in the range of 0.1 to 100 parts by weight, but preferably 1 to 50 parts by weight, based on 100 parts by weight of the hydroxyl group-containing conjugated diene polymer as the raw material. is within the range of

In addition, hydrogen can be used in a flow system at normal pressure or in a
It may be used under a certain degree of pressure, and the hydrogenation reaction may be carried out in a fixed bed,
Any reaction method, such as a suspension method, can be employed.

In the method of the present invention, at least 50% of the unsaturated portion of the hydroxyl group-containing conjugated diene polymer as a raw material, usually
0 or more is hydrogenated.

Further, the hydrogenation rate is fast, and the number of hydroxyl groups per molecule hardly changes from that of the raw material.

That is, since cleavage of hydroxyl groups does not occur, curing can be carried out extremely easily in subsequent steps using a conventionally known curing agent such as polyisocyanate. During curing, reinforcement or modification can be performed using fillers such as cargo plastic, phosphor, hydrated silica, clay, Merck, mica, organic fibers, and inorganic fibers.

EXAMPLES Hereinafter, the present invention will be explained in more detail according to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 Polyhydroxypolyisoprene (Mn=
2,600, OH value = 45.3 Jn9/if) 10
0g, reduced nickel 10g and nickel loading amount 40
% (carrier: Quaint earth) and 200 g of tetrahydro7ran as a reaction solvent, and after replacing the gold in the system with purified nitrogen gas, the temperature was raised to 150° C. over 30 minutes.

When the temperature reached a steady state of 150°C, high-purity hydrogen gas was supplied to the autoclave, and the hydrogenation reaction was carried out while maintaining the system internal pressure at 50 kg/6n2. The hydrogenated product was removed from the reaction for a predetermined period of time, the filtered catalyst was removed, and the solvent was distilled off to obtain a hydrogenated product.

The analytical values of the obtained hydrogenated product are shown in Table-1.

Example 2 Double-terminated hydroxy polyisoprene (Mn = 10
,000, OH value = 10.5X9? ) 50 grams, 40% nickel supported on 3 grams of reduced nickel), 1,4-
200 grams of dioxane was charged and a hydrogenation reaction was carried out in the same manner as in Example 1.

The analytical values of the obtained hydrogenated product are shown in Table-1.

Comparative Example 1 A hydrogenation reaction was carried out in the same manner as in Example 1 except that 200 grams of cyclohexane was used instead of tetrahydrofuran as the solvent to obtain a hydrogenated product. The analytical values of the obtained hydrogenated product are shown in Table 1.

From this result, it became clear that the achieved hydrogenation rate was low with cyclohexane solvent.

Comparative Example 2 A hydrogenation reaction was carried out in the same manner as in Example 1 except that 10 grams of Raney nickel was used as a catalyst instead of reduced nickel to obtain a hydrogenated product. Table 1 shows the analytical values of the obtained hydrogenated products.
It was shown to.

These results revealed that the Raney nickel catalyst achieved a low hydrogenation rate.

Example 3 A hydrogenation reaction was carried out in the same manner as in Example 1 except that a mixed solvent consisting of 70% by weight of ethyl ether and 30% by weight of cyclohexane was used as the solvent. The analytical values of the obtained hydrogenated product are shown in Table-1.

Comparative Example 3 A hydrogenation reaction was carried out in the same manner as in Example 1 except that Inflovir alcohol was used as the solvent. The analytical values of the obtained hydrogenated product are shown in Table-1.

The results revealed that the hydrogenation reaction using diimpropyl alcohol as a solvent caused a large amount of cleavage of hydroxyl groups.

Examples 4 to 7 A p1 hydrogenation reaction was carried out under the conditions shown in Table-IK, and the results are shown in Table-1.

Comparative Examples 4 to 6 Hydrogenation reactions were carried out under the conditions shown in Table IK, and the results are shown in Table I.

The following margin (effects of the invention) In the hydrogenation of a hydroxyl group-containing conjugated diene system according to the method of the present invention, reduced nickel is used as a catalyst and an ether solvent or a mixed solvent of an ether solvent and a hydrocarbon solvent is used as a solvent. When K is used, an extremely high hydrogenation rate can be achieved with almost no cleavage or elimination of hydroxyl groups. Therefore, the industrial value of the present invention in the field of producing raw materials for polyurethane, polyester, etc. is extremely high.

Claims (6)

[Claims] (1) A method for catalytic hydrogenation of a hydroxyl group-containing conjugated diene polymer, characterized in that reduced nickel is used as a catalyst, and an ether solvent or a mixed solvent of an ether solvent and a hydrocarbon solvent is used as a solvent. how to. (2) The conjugated diene polymer referred to in the hydroxyl group-containing conjugated diene polymer is a homopolymer of conjugated diene monomers, a copolymer of two or more conjugated diene monomers, or a conjugated diene monomer and a vinyl monomer. The method according to claim 1, which is a copolymer of. (3) The method according to claim 2, wherein the conjugated diene polymer is polyisoprene. (4) The method according to claim 1, wherein the hydroxyl group-containing conjugated diene polymer has hydroxyl groups at both ends of the molecule. (5) The method according to claim 1, wherein the solvent is a cyclic ether. (6) The method according to claim 1, wherein the cyclic ether is tetrahydrofuran or dioxane.