JP2002338620A - Production method for hydrogenated hydroxyl-group- containing conjugated diene polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for a hydrogenated hydroxyl-group- containing conjugated diene polymer whereby a hydroxyl-group-containing conjugated diene polymer can be hydrogenated to a high hydrogenation degree easily and conveniently at a low cost without causing the coloration of the resultant polymer and without causing the cutting or separation of hydroxyl groups. SOLUTION: In this method for producing a hydrogenated hydroxyl-group- containing conjugated diene polymer by hydrogenating a hydroxyl-group- containing conjugated diene polymer, Raney nickel and palladium carbon are used together as catalysts; and an alcohol solvent, an ether solvent, a hydrocarbon solvent, or a mixture of these solvents is used as a solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a hydrogenated conjugated diene polymer having a hydroxyl group, and more particularly to a method for producing a hydrogenated conjugated diene polymer having a terminal hydroxyl group. The present invention relates to a production method which has a high degree of hydrogenation, does not cause coloration in the resulting polymer product, and can prevent cleavage or elimination of hydroxyl groups. The polymer product obtained by this production method is useful, for example, as a raw material for producing a polyurethane by reacting with a diisocyanate compound.

[0002]

2. Description of the Related Art Hydroxy group-containing conjugated diene polymers, particularly polyisoprene, polybutadiene or polychloroprene having a hydroxyl group at a molecular terminal, have characteristic properties as raw materials for polyurethane and the like. However, this polyurethane is inferior in weather resistance and heat resistance because of the unsaturated bond present in the conjugated diene polymer. Therefore, for the purpose of improving weather resistance and heat resistance, it is common to hydrogenate unsaturated bonds in the presence of a catalyst. Examples of the hydrogenation catalyst used for such a hydrogenation reaction include nickel,
There are known palladium, ruthenium, and rhodium supported on a carrier such as carbon, silica, alumina, and diatomaceous earth, and Raney nickel and Raney cobalt without using a carrier. However, when the above catalysts are used individually, problems such as a low hydrogenation rate of the polymer, coloring of the obtained polymer product, and cleavage of the hydroxyl group occur.

On the other hand, as a method for hydrogenating a diene polymer having a hydroxyl group, there has been disclosed a method for hydrogenating in the presence of a catalyst comprising two kinds of Group VIII metals, including nickel, supported on a carrier. (Japanese Patent Laid-Open No. 62-13 / 1987)
No. 2902). In the above method, the step of preparing the catalyst, that is, the step of supporting two kinds of metals on the carrier becomes complicated, the catalyst becomes expensive, and the performance of the catalyst changes depending on the type of the carrier, or the same carrier is used. However, there is a problem in that the variation in the pore diameter affects the reaction rate, and it is not necessarily an industrially advantageous method.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the resulting polymer has no coloring, can prevent cleavage or elimination of hydroxyl groups, and can be produced at low cost. An object of the present invention is to provide a method for producing a hydrogenated hydroxyl-containing conjugated diene polymer which can easily hydrogenate a hydroxyl-containing conjugated diene polymer at a high hydrogenation rate.

[0005]

According to the present invention, the above object is achieved by hydrogenating a conjugated diene polymer having a hydroxyl group,
When producing a hydrogenated hydroxyl group-containing conjugated diene polymer, Raney nickel and palladium carbon are used in combination as a catalyst, and an alcohol solvent, an ether solvent or a hydrocarbon solvent or a mixed solvent thereof is used as a solvent. This is achieved by providing a method for producing a hydrogenated hydroxyl group-containing conjugated diene polymer characterized by the following.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The “hydroxyl-containing conjugated diene-based polymer” to which the production method of the present invention is applied is a conjugated diene-based polymer having a hydroxyl group in a molecule, for example, 1,3-butadiene, 1,3-pentadiene , Isoprene, 2.3-dimethylbutadiene, phenylbutadiene and the like, and is a polymer having a hydroxyl group in a molecule produced by a known method using a monomer as a raw material. Further, not only a homopolymer of the conjugated diene monomer but also a copolymer obtained from two or more conjugated diene monomers and a copolymer obtained from a conjugated diene monomer and a vinyl monomer. As long as the polymer has a hydroxyl group in the molecule, the polymer is also included in the “hydroxyl group-containing conjugated diene polymer”. When two or more conjugated diene-based monomers are copolymerized, the ratio between the components is not particularly limited and may be arbitrary. Examples of the vinyl monomer include styrene, vinyl toluene, α-methylstyrene, vinyl naphthalene,
Coumarone indene, vinyl pyridine, vinyl furan, acrylonitrile, ethyl acrylate, methyl acrylate, methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylic acid, methacrylic acid and the like. When such a vinyl monomer is used, the amount is preferably less than 80% by mass, more preferably less than 50% by mass of all monomers constituting the polymer.

The number of hydroxyl groups in the “hydroxyl-containing conjugated diene polymer” used herein is not particularly limited. However, as the number of hydroxyl groups in the hydroxyl-containing conjugated diene polymer increases, the number of hydroxyl groups increases. Since the hydroxyl group is likely to be cleaved and the hydrogenation catalyst is easily deactivated,
The number is preferably 1 to 10 in one molecule of the polymer, and 2 to 10
More preferably, the number is eight.

The number average molecular weight ( _Mn ) of the hydroxyl group-containing conjugated diene polymer used in the present invention is not particularly limited, but is 500 to 100,000, preferably 700.
Preferably it is in the range of ８０80,000. With an oligomer having a number average molecular weight of less than 500, the flexibility of a polyurethane obtained using the hydride tends to be insufficient. On the other hand, a polyurethane obtained by using a hydride of a hydroxyl group-containing conjugated diene polymer having a number average molecular weight of more than 100,000 has poor compatibility between a hard segment and a soft segment, and has a large hard segment and low mechanical strength. It tends to decrease. The number average molecular weight described here is determined by gel permeation chromatography (GP
It is a number average molecular weight in terms of polystyrene measured by C).

The conjugated diene polymer having a hydroxyl group used in the present invention can be obtained by various methods. For example, one or more conjugated diene-based monomers or a monomer composed of a conjugated diene-based monomer and a vinyl monomer is converted to an azobis-based compound having a hydroxyl group, for example, β, β′-azobis (β- Cyano)
Radical polymerization using -n-propanol, δ, δ'-azobis (β-cyano) -n-pentanol or the like, or an organic peroxide such as hydrogen peroxide, cyclohexane peroxide or methylcyclohexanone peroxide as an initiator. can get. By the above radical polymerization, a hydroxyl group-containing conjugated diene polymer having a hydroxyl group at at least one end can be obtained.

Alternatively, the above monomer may be an alkali metal such as sodium or lithium; an alkyllithium compound such as n-butyllithium, sec-butyllithium or t-butyllithium; or 1,3-phenylenebis (3-methyl-1 −
It can also be produced by anionic polymerization using a dilithium compound such as phenylpentylidene) dilithium as an initiator, and then adding an alkylene oxide such as ethylene oxide or epichlorohydrin to give a hydroxyl group. By the above-described anionic polymerization and hydroxyl group addition, a hydroxyl group-containing conjugated diene polymer having a hydroxyl group at at least one terminal (when an alkali metal or alkyllithium compound is used as a catalyst) or at least both terminals (when a dilithium compound is used as a catalyst) Can be obtained.

In the present invention, a hydroxyl group-containing conjugated diene polymer obtained by the above-described method, particularly a hydroxyl group-containing conjugated diene polymer having a hydroxyl group at least at a molecular terminal, is used in combination with Raney nickel and palladium carbon as a catalyst. And, by hydrogenating using an alcohol-based solvent, an ether-based solvent or a hydrocarbon-based solvent or a mixed solvent thereof as a solvent during the hydrogenation reaction, a hydrogenated hydroxyl-containing conjugated diene-based polymer is produced. . Raney nickel may be in any form, such as powder or granule, or may be commercially available, or may be prepared according to the method described in the literature. Palladium carbon also has different purity and moisture content, but commercially available ones can be used.

The amount and the mixing ratio of Raney nickel and palladium carbon used together as a catalyst in the present invention are not strictly limited, and are determined by the type of solvent used and the target degree of hydrogenation. In general, Raney nickel is used in an amount of 0.01 to 20% by mass, preferably 0.1% by mass, based on the hydroxyl group-containing conjugated diene polymer.
Palladium carbon is used in an amount of 0.01 to 100% by mass, preferably 0.1 to 50% by mass, based on Raney nickel. The method for adding the catalyst is not particularly limited, and Raney nickel and palladium carbon can be added at the same time at the start of the reaction, or the reaction can be started by adding less than a predetermined amount of Raney nickel and / or palladium carbon. Depending on the degree of progress of the reaction, Raney nickel and / or palladium carbon may be appropriately added during the reaction.

In a particularly preferred embodiment of the method for adding a catalyst in the production method of the present invention, Raney nickel is contained in an amount of 0.01 to 20% by mass relative to the hydroxyl group-containing conjugated diene polymer.
The reaction is started preferably by adding 0.1 to 10% by mass and palladium carbon in an amount of 10% by mass or less, preferably 5% by mass or less with respect to Raney nickel. In this method, only hydrogen is added in an amount of 10% by mass or less, preferably 5% by mass or less with respect to Raney nickel to carry out the hydrogenation reaction. When such an addition method is employed, the same degree of hydrogenation can be achieved with a smaller amount of palladium carbon used as compared with the case where the reaction is performed by adding Raney nickel and palladium carbon all at once. Palladium carbon has an activity of eliminating terminal hydroxyl groups of a hydroxyl group-containing conjugated diene polymer in addition to hydrogenation activity, and thus such an addition method is particularly preferable from the viewpoint of suppressing the removal of hydroxyl groups.

The alcohol solvent used in the present invention includes methanol, ethanol, isopropanol, n-
Propanol, i-butanol, n-butanol, ethylene glycol, propylene glycol and the like,
As ether solvents, diethyl ether, di-n-
Chain or cyclic ethers such as butyl ether, diisopropyl ether, diisoamyl ether, diphenyl ether, anisole, phenetole, amyl phenyl ether, tetrahydrofuran, tetrahydropyran, dioxane, trioxane and the like, and examples of the hydrocarbon solvent include hexane, heptane, octane , Cyclohexane, methylcyclohexane, benzene, toluene, xylene and the like. Each of these alcohol solvents, ether solvents and hydrocarbon solvents may be used alone or in combination of two or more. 2
When mixing more than one type, the mixing ratio is determined by the type of solvent used and the target hydrogenation rate and degree of hydrogenation reaction time. Is usually 1 to 100% by mass,
The content is preferably 10 to 90% by mass. The amount of the solvent used is not particularly limited, but is usually 5 to 200% by mass, preferably 10 to 10% by mass, based on the hydroxyl group-containing conjugated diene polymer.
The range is 0% by mass.

The temperature at the time of the hydrogenation reaction in the present invention can be arbitrarily selected in the range of room temperature to 200 ° C., but is preferably in the range of 80 to 180 ° C. If the reaction temperature is lower than room temperature, the rate of the hydrogenation reaction tends to be extremely slow. There is no particular limitation on the hydrogen pressure.
Usually, the pressure is in a range under normal pressure or a pressure of about 100 to 30,000 kPa, and the hydrogenation reaction can be carried out in a usual reaction form such as a fixed bed or a suspension method. In the present invention, at least 70%, usually 80% or more, of the olefinic double bonds of the hydroxyl group-containing conjugated diene polymer can be hydrogenated in a short reaction time of about 10 hours.

The hydrogenation rate of the obtained hydrogenated hydroxyl-containing conjugated diene polymer can be changed according to the purpose. The hydrogenation rate can be determined by measuring the iodine value of the polymer before and after the hydrogenation reaction, and a polymer having a predetermined hydrogenation rate can be obtained. Further, in the present invention, the number of hydroxyl groups per molecule of the obtained hydrogenated hydroxyl-containing conjugated diene polymer hardly changes as compared with that of the raw material. That is, the cleavage of the hydroxyl group hardly occurs. Therefore,
When reacting this product with a polyisocyanate or the like, the reaction can be easily carried out.

[0017]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited thereto. The hydrogenation rate of the hydrogenated hydroxyl-containing conjugated diene polymer was determined by performing an iodine value titration before and after the hydrogenation reaction. The hydroxyl value is determined by weighing a predetermined amount of a hydroxyl group-containing conjugated diene-based polymer or a hydrogenated hydroxyl group-containing conjugated diene-based polymer, acetylating the hydroxyl group with an excess amount of acetic anhydride / pyridine, and then acetylating the remaining anhydride. It was calculated by titrating acetic acid with an aqueous solution of potassium hydroxide.

Reference Example 1 300 g of hexane as a solvent, 68 g of isoprene as a monomer, and a 30% by mass aqueous hydrogen peroxide solution 1 as an initiator
25 g was charged in a 1 L autoclave, heated to 80 ° C. with stirring, and polymerized for 20 hours to obtain polyisoprene having a hydroxyl group (Mn = 2,600, hydroxyl value 53.6 mg / g).

Example 1 In a 1 L autoclave, 480 g of the hydroxyl group-containing polyisoprene obtained by the method of Reference Example 1 (M _n = 2,600, hydroxyl value 53.6 mg / g), Raney nickel (water content 50%) With respect to the hydroxyl group-containing polyisoprene.
0 mass%, 5% palladium carbon (water content: 50%) was charged with 5 mass% with respect to Raney nickel, and 120 g of isopropanol was charged as a solvent, and the inside of the system was replaced with purified nitrogen gas. The temperature rose. 1
When the steady state at 20 ° C. was reached, high-purity hydrogen gas was supplied into the autoclave, and a hydrogenation reaction was performed while maintaining the internal pressure of the system at 1,000 kPa. After the reaction for 8 hours, the catalyst was removed by filtration, and the solvent was distilled off to obtain a hydrogenated product. Table 1 shows the analysis values of the obtained hydrogenated products. A polymer having a high degree of hydrogenation was obtained with almost no hydroxyl group cleavage.

Example 2 In Example 1, Raney nickel (50% water content) was used as a catalyst for the hydroxyl group-containing polyisoprene.
0 mass%, 5% palladium carbon (water content: 50%) was added to 1 mass% with respect to Raney nickel, and the reaction was carried out for 7 hours in the same manner as in Example 1. Thereafter, 1.75 mass% of Raney nickel with 5.75 mass% was added. % Palladium carbon (water content 5
0%) together with a small amount of isopropanol by pumping into the autoclave, and further added at 120 ° C. and a hydrogen pressure of 10%.
The reaction was performed at 00 kPa for 3 hours. Table 1 shows the analysis values of the obtained hydrogenated products.

Example 3 In Example 1, Raney nickel (water content: 50%) was used as a catalyst for the hydroxyl group-containing polyisoprene.
Example 1 0 mass%, 5% palladium carbon (water content: 50%) was added to Raney nickel at 0.5 mass% to 0.5 mass%.
The reaction was carried out for 6 hours in the same manner as described above, and thereafter, 5% palladium carbon (water content: 50%) of 0.75% by mass with respect to Raney nickel was added to the autoclave by pumping together with a small amount of isopropanol, and further added at 120 ° C. The reaction was performed at a hydrogen pressure of 1000 kPa for 6 hours. Table 1 shows the analysis values of the obtained hydrogenated products.

Comparative Example 1 In Example 1, Raney nickel (water content: 50%) was used as a catalyst for the hydroxyl group-containing polyisoprene.
A hydrogenation reaction was carried out for 16 hours in the same manner as in Example 1 except that 0% by mass was used. Table 1 shows the analysis values of the obtained hydrogenated products. It can be seen that the achieved hydrogenation rate is low despite the large amount of Raney nickel used compared to Examples 1-3. Comparative Example 2 In Example 1, 5% palladium carbon (water content: 50%) was used as a catalyst with respect to hydroxyl group-containing polyisoprene.
%) Was used, and the hydrogenation reaction was carried out for 16 hours in the same manner as in Example 1. Table 1 shows the analysis values of the obtained hydrogenated products. It can be seen that the attainable hydrogenation rate is low and the hydroxyl group is frequently cleaved.

[0023]

[Table 1]

[0024]

According to the present invention, the obtained polymer is not colored, the cleavage or elimination of the hydroxyl group can be prevented, and the conjugated diene containing a hydroxyl group which is inexpensively, easily and hydrogenated at a high hydrogenation rate can be obtained. A polymer can be obtained.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsutomu Yamada 36 Kamisu-cho, Kasumi-gun, Ibaraki Pref.Kuraray Co., Ltd. 72) Inventor Masao Ishii 1-12-39 Umeda, Kita-ku, Osaka City, Osaka Prefecture F-term in Kuraray Co., Ltd. CA04 HA04 HB02 HE41

Claims (2)

[Claims] When producing a hydrogenated conjugated diene-based polymer by hydrogenating a conjugated diene-based polymer having a hydroxyl group, Raney nickel and palladium carbon are used in combination as a catalyst, and an alcohol-based solvent is used as a solvent.
A method for producing a hydrogenated hydroxyl group-containing conjugated diene polymer, comprising using an ether solvent, a hydrocarbon solvent or a mixed solvent thereof. 2. The method according to claim 1, wherein the hydroxyl group-containing conjugated diene polymer is hydroxyl group-containing polyisoprene.