JPH02147605A - Preparation of unsaturated polymer containing partially hydrogenated nitrile groups - Google Patents

Abstract

PURPOSE:To obtain efficiently, easily and with low cost the title unsatd. polymer by hydrogenating partially a nitrile group-contg. unsatd. polymer wherein a conjugated diene and (meth)acrylonitrile are essential components in a hydrogen atmosphere with a homogeneous catalyst in a homogeneous liq. phase. CONSTITUTION:A nitrile group-contg. unsatd. polymer wherein a conjugated diene and (meth)acrylonitrile are essential components (e.g. acrylonitrile- butadiene copolymer or acrylonitrile-butadiene-N-4-anilinophenylmethacrylamide) is partially hydrogenated in a hydrogen atmosphere with a homogeneous catalyst (e.g. dichlorotristriphenylphosphine ruthenium) in a homogeneous liq. phase. Then by distilling out the solvent (e.g. acetone) from the obtd. reaction mixture, an unsatd. polymer contg. partially hydrogenated nitrile groups is obtd.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for producing a partially hydrogenated unsaturated polymer containing two or more IJ groups, and more specifically, it relates to a method for producing a partially hydrogenated unsaturated polymer containing only carbon-carbon double bonds. The present invention relates to a method for producing partially hydrogenated nitrile rubber with particularly improved processability by selectively partially hydrogenating nitrile rubber.

[Conventional technology]

As a method for hydrogenating the carbon-carbon double bond of a conjugated diene polymer, a method using a metal catalyst belonging to group 12 of the periodic table has been known. Catalysts are broadly divided into 1) supported heterogeneous catalysts in which metals are supported on carbon, silica, alumina, diatomaceous earth, etc., and 2) homogeneous catalysts such as metal complex catalysts and Ziegler type catalysts.

In particular, acrylonitrile-butadiene copolymer (hereinafter referred to as N
Abbreviated as BR. ), where oil resistance is significantly reduced when the nitrile group is reduced, only the carbon-carbon double bonds of the conjugated diene moieties in the polymer must be selectively hydrogenated; As a catalyst with selectivity, R
Expensive noble metals such as hXPt and Pd are often used. Moreover, in the case of the hydrogenation reaction of polymers such as NBR, the contact efficiency with the catalyst deteriorates due to the influence of steric hindrance caused by this or the decrease in stirring efficiency due to increased viscosity. Relatively large amounts of catalyst are required to carry out an effective reaction.

[Problem to be solved by the invention]

However, it is known that mixing a catalyst into a hydrogenated polymer has a negative effect on the properties of the polymer, and for economic reasons and physical properties of the polymer, it is not possible to separate the polymer and catalyst. desirable.

Methods for separating such polymers and catalysts include sedimentation, filtration, and centrifugation (Japanese Unexamined Patent Publication No. 17103/1983) for heterogeneous catalysts.
A method has been proposed. however,
In this conventional method, the viscosity of the hydrogenation reaction solution is high and the catalyst separation operation is generally complicated. Furthermore, when the particle size of the supported catalyst is increased with the intention of improving catalyst separation, the hydrogenation activity is greatly reduced. There was a problem that the value decreased.

On the other hand, the hydrogenation reaction of NBR using a homogeneous catalyst is known to use rhodium (JP-A-60-60106) and ruthenium (JP-A-61-78802) compounds; Regarding the separation and recovery of the polymer, there are no specific proposals, and in general, there are methods such as bringing the polymer solution into direct contact with water vapor without separating the catalyst, or adding a poor solvent to the polymer solution to separate the polymer. Hydrogenated polymers are simply recovered by methods such as sedimentation. However, according to JP-A-60-60106, for example, in such a method in which the catalyst is not separated, the amount of catalyst that can be effectively used for the hydrogenation reaction remains in the polymer, and the properties of the polymer,
In particular, cases have been shown in which the processability of hydrogenated rubber is not adversely affected, that is, cases in which the Mooney viscosity increases significantly depending on the amount of coexisting catalyst. And 1 of the hydrogenated polymer
, -2- The viscosity varies depending on the use or processing method, but is usually preferably ML, +4 (100°C)
= about 100 or less, more preferably ML, +4 (100
℃)=approximately 80 or less. Considering the above case, in order to obtain a hydrogenated product with a relatively low Mooney viscosity, the conventional method is to estimate the Mooney viscosity that will increase due to the hydrogenation reaction and produce NBR with a low Mooney viscosity in advance and hydrogen A choice had to be made between subjecting the hydrogenated polymer to the hydrogenation reaction, or recovering the hydrogenated polymer after achieving the desired hydrogenation rate with the smallest possible amount of catalyst.

However, the conventional method of hydrogenating pre-produced NBR with a low Mooney viscosity as a raw material leads to deterioration of hydrogenated rubber physical properties such as tensile strength, fatigue resistance, and compression set, so the Mooney viscosity of the raw material NBR is reduced. There is a limit to the conventional method of producing hydrogenated polymers by reducing the amount of catalyst used as much as possible. There was a problem in that the reaction conditions had to be made harsher.

The present invention solves the above-mentioned conventional problems by providing a partially hydrogenated rubber composition with improved processability, particularly a partially hydrogenated rubber composition with good processability as a vulcanizate. An object of the present invention is to provide a simple method for producing an unsaturated polymer containing -IJ groups.

[Means to solve the problem]

As a result of intensive studies to achieve this objective, the present inventors have discovered that using a homogeneous catalyst, the carbon-carbon double bonds of a nitrile group-containing unsaturated polymer are selectively hydrogenated in a homogeneous liquid phase. For the first time, we have discovered that when a specific means is used to separate and obtain the obtained partially hydrogenated product, the increase in Mooney viscosity of the partially hydrogenated product can be suppressed as much as possible, and the present invention was achieved based on this finding. That is, the present invention provides a nitrile group-containing unsaturated polymer comprising a conjugated diene and acrylonitrile or methacrylonitrile as essential components,
Partial hydrogenation is carried out in a homogeneous liquid phase using a homogeneous catalyst in a hydrogen atmosphere, and then the solvent is distilled off or evaporated from the resulting reaction mixture to obtain the partially hydrogenated polymer. The gist of this article is a method for producing an unsaturated polymer containing partially hydrogenated IJ groups.

The present invention will be explained in detail below.

The conjugated diene-based nitrile group-containing unsaturated polymer used in the present invention is a copolymer of acrylonitrile or methacrylonitrile and a conjugated diene monomer, or a copolymer of acrylonitrile or methacrylonitrile and the conjugated diene and It is a copolymer of acrylonitrile or methacrylonitrile and one or more other monomers copolymerizable with the conjugated diene.

Conjugated diene monomers include 1,3-butanene, 2
, 3-dimethylbutadiene, isoprene, 1.3-pentadiene, and 1.3-cyclopentadiene, and 1,3-butadiene is preferably used.

In addition, monomers that can be combined with acrylonitrile or methacrylonitrile and the above-mentioned conjugated dienes, alkenyl aromatic hydrocarbons such as styrene, α-methylstyrene, and divinylbenzene, itaconic acid, fumaric acid,
Maleic acid, acrylic acid, ethylene glycol dimeta-
An amino group or Examples include vinyl compounds containing at least one imino group.

OOH In the formula, R1 and R2 are a hydrogen atom, a chlorine atom, a bromine atom, or an alkyl group having 1 to 12 carbon atoms, R3 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R4 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
R5 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or a group of -0H, -(CH2)n, -0-0-, respectively.

However, n is an integer from 2 to 8.

Examples of general formula (1) include N-(4-anilinophenyl)acrylamide, N-(4-anilinophenyl)
Methacrylamide, N-(4-7=lJ nophenyl)cinnamamide, N-(4-anilinophenyl)crotonamide, N-(4-(4-methylanilino)phenylcoacrylamide, N-(4-( 4-methylanilino)phenyl]methacrylamide, 3-N-(4
-anilinophenyl, )amino-2hydroxypropyl-allyl ether or -metallyl ether, 9-hydroxydi-1O-n-octyl de/ruacrylate or -
Examples thereof include methacrylate, 5-N-(4-anilinophenyl)amino-2-hydroginebenzene acrylate or -methacrylate, and 2-N-(4-anilinophenyl)aminoethyl-acrylate or -methacrylate.

Further, as an example of general formula (II), N-(4-anilinophenyl)maleimide, N-(:4-(4-meI)
Examples include F-ruanilino) phenylcomaleimide.

As an example of general formula (1), N-7enyl-4-(3-
Examples of general formula (IV) such as vinylbenzyloxy)aniline include N-phenyl-4-(4-vinylbenzyloxy)aniline and the like.

The quantitative ratio of these is preferably about 52 to 85 wt% of the conjugated diene, about 15 to 4 wt% of acrylonitrile or methacrylate trile, and 0 to IQ wt% of other monomers.

These copolymers may be produced by any polymerization method such as emulsion polymerization, solution polymerization, or bulk polymerization, but in order to make more effective use of the advantages of the present invention, the number average molecular weight of the polymer is Preferably, the number is 5000 or more.

A good partial hydrogenation reaction can be carried out by dissolving the copolymer in an appropriate organic solvent.

The solvent for such partial hydrogenation reaction has 3 to 10 carbon atoms.
Low molecular weight ketones such as acetone, butanone, pentanone, Schiff-copentanone and cyclohegisanone are used.

The concentration of unsaturated copolymer relative to the total solution is from 1 to 20% by weight, preferably from 2.5 to 10% by weight, based on the abovementioned solvent.
It is.

As the catalyst in the process of the invention, a homogeneous catalyst of ruthenium and an organic bosphinic compound is used.

A method using a homogeneous rutinium catalyst is described, for example, in JP-A-6
It is disclosed in JP-A-1-78802, JP-A-62-42937, JP-A-62-125858, and the like.

Any form of ruthenium compound and organic phosphine compound other than those mentioned above may be used, but the degree of partial hydrogenation of the obtained polymer should be 80% or more, preferably 90%.
% or more.

2) In the present invention, the concentration of the catalyst (calculated as ruthenium) for the IJ group-containing unsaturated polymer is 10 to 101
000 ppm preferably 1 O to 600 ppm.

More preferably, it is in the range of 40 to 500 ppm.

To carry out the partial hydrogenation reaction, a reaction vessel is charged with a solution containing 1 to 20% by weight, preferably 2.5 to 10% by weight of the unsaturated copolymer, catalyst components, Hydrogen gas may be introduced into this.

After the partial hydrogenation reaction, a known antioxidant such as a hindered phenol or an organic disulfide compound may be added as a stabilizer, if necessary.

After that, the partially hydrogenated polymer is separated from the solution by distilling off the solvent under reduced pressure or by a drum drying method in which the polymer solution is dropped onto a heated rotating drum to evaporate the solvent, and then drained and heated with hot air. After undergoing a drying process such as drying, vacuum drying, or extrusion drying, it is recovered as a solid partially hydrogenated polymer.

The partially hydrogenated polymer of the present invention thus obtained has a relatively low Mooney viscosity and can be processed relatively easily. That is, Mooney viscosity is a measure of the processability of an elastomer (p, s, y 7 , Kau
tschuk und Gummi.

Kunststoffe, 33.725 (1980
)], products with a relatively low Mooney viscosity can be easily processed and can be carried out better and more economically with respect to energy consumption, for example by mixing, extrusion, injection molding, etc.

A vulcanizate with excellent properties can be obtained from the rubber partially hydrogenated according to the method of the present invention by sulfur vulcanization in a conventional manner.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these Examples unless it exceeds the gist thereof.

Note that Mooney viscosity is measured according to JIS K6300.

Example 1 In an autoclave of i117I, acrylonitrile-butadiene copolymer [acrylonitrile B4 owt%
, ML1+4 (100°C) = 53) 2 oyr to 500 rrB of acetone! dichlorotrist IJ
122m7 of phenylphosphine ruthenium and 0.18m7 of triethylamine! was added, and after replacing the inside of the autoclave with hydrogen gas, the temperature was raised to 145°C. When the temperature reached 145℃, hydrogen gas was injected to 50KG and heated at constant pressure for 4 hours.
A time partial hydrogenation reaction was carried out. Thereafter, acetone was distilled off from the partial hydrogenation reaction solution under reduced pressure in an oil bath at 50°C.

The obtained partially hydrogenated polymer was vacuum dried at 50°C for 14 hours.

As a result, the hydrogenation rate was determined to be 92 H by the iodine value method, and the Mooney viscosity of the obtained solid partially hydrogenated polymer was ML, +4 (100°C) = 10.4.

Example 2 The same procedure as Example 1 was carried out, except that after the partial hydrogenation reaction in Example 1, 2 parts by weight of hindered phenol as an antioxidant was added as a stabilizer to 100 parts by weight of the raw material acrylonitrile-butadiene copolymer. A similar operation was performed.

As a result, the Mooney viscosity of the obtained solid partially hydrogenated polymer was ML1+4 (100° C.)=76.

Comparative Example 1 In an autoclave with a capacity of 1e, acrylonitrile-butadiene copolymer [acrylonitrile t 40 wt%,
Dissolve ML1+4(100°G)=sa)2oyr in 500 mJ of acetone, dichlorotristriphenylphosphine ruthenium xzzmy and U triethylamine 0
．． After adding 18m71 of the autoclave and purging the inside of the autoclave with hydrogen gas, the temperature was raised to 145°C. When the temperature reached 145° C., 50 kg of hydrogen gas was introduced under pressure, and a partial hydrogenation reaction was carried out at constant pressure for 4 hours. After that, a large amount of water was added to the hydrogenation reaction solution to recover the partially hydrogenated polymer, and after draining, 50' (
: vacuum drying for 14 hours.

As a result, the Mooney viscosity of the obtained solid partially hydrogenated polymer was ML1+4 (100°C) = 130, and compared to Example 1, the operation was exactly the same except for the recovery method of the partially hydrogenated polymer. Nevertheless, a significant increase in Mooney viscosity was observed.

Example 3 Acrylonitrile-butadiene-N-(4-anilinophenyl)- in an induction-stirred autoclave of 1 volume.
Methacrylamide copolymer [Bound acrylonitrile amount 4
twt%, N-4 anilinophene methacrylamide 1
wt%.

ML 1+4(1,00℃)=44)2orr was dissolved in 500ml of acetone, and 122ml of dichlorotristriphenylphosphineruthenium was added as a partial hydrogenation catalyst.
? and IJ ammonium hexafluorophosphate 10
After adding 4my and replacing the inside of the autoclave with hydrogen gas, the temperature was raised to 145°C. When the temperature reached 145°C, the pressure of hydrogen gas was increased by 50KG, and the reaction was carried out at constant pressure for 8 hours.

Thereafter, acetone was distilled off from the hydrogenation reaction solution under reduced pressure in an oil bath at 50°C. The partially hydrogenated polymer obtained was 50
It was vacuum dried at ℃ for 14 hours.

As a result, the hydrogenation rate was determined to be 95 by the iodine value method, and the Mooney viscosity of the obtained solid partially hydrogenated polymer was ML1+4 (100°C) = 94.

Example 4 After the partial hydrogenation reaction in Example 3, the same operation as in Example 3 was carried out, except that 2 parts by weight of hindered phenol, an antioxidant, was added as a stabilizer per 100 parts by weight of the raw material copolymer. went.

As a result, the Mooney viscosity of the obtained solid partially hydrogenated polymer was ML, +4 (100°C) = 90.

Comparative Example 2 Acrylonitrile-butadiene-N-(4-anilinophenyl) in induced stirred mate crepe with volume 4゛IE
-Methacrylamide copolymer [bonded acrylonitrile B
4iwt%, N-4 anilinophene methacrylamide 1wt%.

ML, +4(100℃)=44)2orr was dissolved in 500ml of acetone, and 122mv of dichlorotristriphenylphosphineruthenium was added as a partial hydrogenation catalyst.
and ammonium hexafluorophosphate 104m
After adding F and replacing the inside of the autoclave with hydrogen gas, 1
The temperature was raised to 45°C.

When the temperature reached 145°C, the pressure of hydrogen gas was increased by 50KG, and the reaction was carried out at constant pressure for 8 hours. After that, a large amount of water is added to the hydrogenation reaction solution to recover the hydrogenated polymer, and after draining,
It was vacuum dried at 50°C for 14 hours.

As a result, the Mooney viscosity of the obtained solid partially hydrogenated polymer was ML, +4 (100°C) = 155.Compared to Example 3, the operation was exactly the same except for the method of recovering the partially hydrogenated polymer. Despite this, a large increase in l,-2-viscosity was observed.

Example 5 Acrylonitrile-butadiene copolymer [acrylonitrile amount 41
Wt, ML1+4 (100°C) = 3 & 9) 20Pr was dissolved in 500rM acetate, 122mF of dichlorotristriphenylphosphine ruthenium and 0.18m7I of triethylamine were added, and after purging the inside of the autoclave with hydrogen gas, the temperature was raised to 145°C. . When the temperature reached 145° C., hydrogen gas was introduced under pressure into 5 OKG, and the reaction was carried out at constant pressure for 7 hours. Thereafter, the partially hydrogenated polymer was recovered by the same treatment as in Example 2, and vacuum-dried at 50° C. for 14 hours.

As a result, the hydrogenation rate was determined to be 963 H by the iodine value method, and the Mooney viscosity of the obtained partially hydrogenated polymer was ML, +4 (100°C) = 72.

Example 6 Same as Example 5 except that the amount of acrylonitrile-butadiene used in Example 5 was changed to 40 liters, and hydrogen gas was pressurized at 26 kg and reacted at constant pressure for 11.5 hours. The partially hydrogenated polymer was recovered by the same treatment as in Example 2, and vacuum-dried at 50° C. for 14 hours.

As a result, the hydrogenation rate was determined to be 924 by the iodine value method, and the Mooney viscosity of the obtained solid partially hydrogenated polymer was %IL1+4 (100°C) = 47.

〔Effect of the invention〕

As is clear from the above results, in the method for producing a partially hydrogenated IJ group-containing unsaturated polymer of the present invention, partial hydrogenation is performed in a homogeneous liquid phase using a homogeneous catalyst, and By adopting a simple production method in which the hydrogenated polymer is separated by distilling or evaporating the solvent from the partial hydrogenation reaction mixture and obtained as a solid,
Partial hydrogenation is easily carried out, with a hydrogenation rate of at least 9
It reaches a coefficient of 0 or higher, preferably 95 or higher, and requires much less catalyst than conventional methods using heterogeneous catalysts. shows a Mooney viscosity ML1+4 (at 100°C) of at least about 100 or less, preferably about 80 or less, and has improved processability compared to conventional methods. This produces a remarkable effect of industrial value, in that a vulcanizate with improved properties can be obtained.

Special applicant Mitsubishi Kasei Corporation Agent: Patent Attorney Tsunebe Kogawa

Claims (4)

[Claims] (1) A nitrile group-containing unsaturated polymer containing a conjugated diene and acrylonitrile or methacrylonitrile as essential components is partially hydrogenated in a homogeneous liquid phase using a homogeneous catalyst in a hydrogen atmosphere, and the resulting reaction mixture is then obtained. 1. A method for producing a partially hydrogenated nitrile group-containing unsaturated polymer, which comprises distilling or evaporating the solvent to obtain the partially hydrogenated polymer. (2) The nitrile group-containing unsaturated polymer is a polymer consisting of a conjugated diene, acrylonitrile or methacrylonitrile, and another monomer copolymerizable with the conjugated diene and/or acrylonitrile or methacrylonitrile. The manufacturing method according to claim 1, wherein: (3) The production method according to claim 1, wherein the homogeneous catalyst is a compound consisting of ruthenium and phosphine. (4) As a solvent during partial hydrogenation, the number of carbon atoms is 3 to 10
2. The method according to claim 1, wherein the ketones are used.