JPH0331334A - Stabilized rubber-like diene-based polymer composition and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject composition, good in color tone, excellent in stability without coloring in preservation for a long period and useful as a raw material for styrene-based impact-resistant resins by adding a specific antioxidant and organic carboxylic acid in a specified proportion to a rubber-like polymer. CONSTITUTION:A composition obtained by adding (B) a terminator to (A) a solution of a rubber-like polymer prepared by polymerizing (ii) a conjugated diene or copolymerizing the component (ii) with (iii) a vinyl aromatic hydrocarbon in an inert bydrocarbon solvent using (i) an organolithium compound as an initiator, adding (C) a monophenolic type antioxidant having <=250 molecular weight, (D) a monophenolic type antioxidant having >=300 molecular weight and (E) an organic carboxylic acid having a value of 8-30 obtained by dividing the number of carbon atoms in the molecule by the number of carboxyl groups thereto and then recovering the resultant polymer. When the amount of the added component (C) is a pts.wt. and the amount of the added component (D) is b pts.wt. respectively based on 100 pts. wt. component (A), the ratios of the components are as follows. a:b=(10:1)-(1:2), [(1/2a)+b]=0.1-3 and a<2. Furthermore, the component (E) is added in an amount of 0.01-0.5 equiv. based on Li atoms in the component (i).

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a rubber-like conjugated diene polymer composition with excellent stability and good color tone, which is particularly suitable for raw material rubber of styrenic impact-resistant resin. and its manufacturing method.

[Prior Art] Conventionally, as a technique for producing a composition of a rubber-like conjugated diene polymer with excellent stability and good color tone, which is the object of the present invention, a terminator is added to a solution of a living polymer, A method of adding an acid as an anti-coloring agent, adding a stabilizer, and then recovering the polymer (JP-A-58-168812), and a composition containing a specific phenolic stabilizer and a fluorescent brightener. (Japanese Unexamined Patent Publication No. 62-153329) or a method in which carbon dioxide gas is brought into contact after adding a stabilizer and a stopper (Japanese Unexamined Patent Publication No. 62-153329).
-264802) and the like were known.

[Problems to be Solved by the Invention] However, although these techniques have relatively improved the color tone, a well-balanced rubber with sufficient stability has not yet been obtained.

The object of the present invention is to provide a rubber-like conjugated diene polymer composition that solves these problems and has excellent stability and color tone, and a method for producing the same.

[Means for Solving 3a] The present inventors have conducted intensive studies to solve the above problem 11, and found that a specific combination of stabilizers is used in a specific amount ratio in a rubber-like polymer, and A composition containing a specific amount of organic carboxylic acid has a desired color tone, does not become colored even after long-term storage, and has extremely excellent dynamic and static stability. The present inventors have discovered that a rubber-like conjugated diene polymer composition can be obtained, and have completed the present invention.

That is, the present invention provides a rubbery polymer obtained by polymerizing a conjugated diene or a conjugated diene and a vinyl aromatic hydrocarbon using an organolithium compound as an initiator, and (A) a monophenol type antioxidant having a molecular weight of 250 or less; (B) a monophenol type antioxidant with a molecular weight of 300 or more and (C) an organic carboxylic acid whose value obtained by dividing the number of carbon atoms in the molecule by the number of carboxyl groups is 8 to 30 per 100 parts by weight of the rubbery polymer. , (A) component is 8 parts by weight, (
B) When the component is a b-heavy part, a:b is 1O:1 to 1
:2 ratio, [(1/2)a+b] is 0.1 to 3,
and a is in a range of 2 or less, and a stabilized rubbery diene polymer containing component (C) in an amount of 0.01 to 0.5 equivalents relative to the lithium atom in the rubbery polymer. A composition and a method for producing the same.

The present invention will be explained in detail below.

In the present invention, a solution of a rubbery polymer is produced by polymerizing a conjugated diene in an inert hydrocarbon solvent or copolymerizing a conjugated diene and a vinyl aromatic hydrocarbon using an organolithium compound as an initiator. do.

The organic lithium compounds used in this case include organic monolithium compounds, organic dilithium compounds, and organic polylithium compounds in which one or more lithium atoms are bonded in the molecule, such as ethyllithium, n-propyllithium,
Isopropyllithium, n-butyllithium, 5ee-
Examples include butyl lithium, tert-butyl lithium, hexamethylene dilithium, butadienyl dilithium, isoprenyl dilithium, and the like. These may be used not only alone, but also as a mixture of two or more. In addition, the inert hydrocarbon solvent is a solvent that does not substantially stop anionic polymerization, such as butane, pentane, hexane,
Aliphatic hydrocarbons such as isopentane, heptane, octane, and isooctane; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane; and aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene. etc. can be used. These may be used not only alone, but also as a mixture of two or more.

The conjugated diene used in the present invention is a diolefin having a pair of conjugated double bonds, such as 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene),
Examples include 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and particularly common ones include 1,3-butadiene and isoprene. These may be used not only alone, but also as a mixture of two or more.

Vinyl aromatic hydrocarbons used in the method of the present invention include styrene, 0-methylstyrene, p-methylstyrene, p-methylstyrene,
Examples include -tert-butylstyrene, 3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene, and particularly common ones include styrene, p-methylstyrene, and α-methylstyrene. These may be used not only alone, but also as a mixture of two or more.

In addition, polyvinyl compounds such as divinylbenzene, trivinylbenzene, divinylnaphthalene and other polyvinyl aromatic compounds, 3,6-
Hydrocarbon compounds having two independent conjugated diene groups, such as symethylene-1,7-octadiene, 3,11-dimethylene-1,12-tridecadiene, and L, 3,7,9-decatetraene, may also be used.

In the present invention, polar compounds and Randomizing agents can be used. Polar compounds and randomizing agents include ethers, amines, thioethers, phosphoramide,
Examples include alkylbenzene sulfonates, potassium or sodium alkoxides, and the like. Examples of suitable ethers are dimethyl ether, diethyl ether, diphenyl ether and tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, bis-oxolanylpropane, oxolanylpropane oligomers. Examples of amines include tertiary amines such as trimethylamine, triethylamine,
In addition to tetramethylethylenediamine, cyclic tertiary amines can also be used. Phosphines and phosphoramides include triphenylphosphine and hexamethylphosphoramide. Randomizing agents include potassium or sodium alkylbenzene sulfonate, potassium or sodium butoxide, and the like.

The polymerization temperature for producing the polymer in the present invention is generally -10°C to 150°C, preferably 40°C to 12°C.
It is 0°C. The time required for polymerization varies depending on the conditions, but is usually within 48 hours, particularly preferably 1 to 1
It is 0 hours. Further, it is desirable to replace the atmosphere of the polymerization system with an inert gas such as nitrogen gas. The polymerization pressure is not particularly limited as long as it is within a pressure range sufficient to maintain the monomer and solvent in a liquid phase within the above polymerization temperature range. Furthermore, care must be taken to avoid contamination of the polymerization system with impurities that would inactivate the catalyst and living polymer, such as water, oxygen, carbon dioxide, and the like.

The weight average molecular weight of the polymer thus obtained is generally 5.000 to 5,000.000, preferably io
,ooo~1.000.000. The amount of hydrocarbon in the polymer solution is generally from 50 parts by weight to 2000 parts by weight based on 100 parts by weight of the polymer. Depending on the properties of the polymer, the polymer may be insoluble in the hydrocarbon solvent and may be obtained in a suspended state; however, in the present invention, these will also be referred to as a polymer solution.

Further, in the present invention, a polymer solution obtained by partially or selectively hydrogenating the polymer obtained by double polymerization by a hydrogenation reaction (hydrogenation reaction) can be used. The hydrogenation rate can be selected arbitrarily, and when improving heat deterioration resistance etc. while maintaining the properties of the unhydrogenated polymer, the aliphatic double bond based on the conjugated diene is 3% or more and less than 80%. , preferably 5% or more and less than 75% hydrogenation, and in order to improve heat deterioration resistance and weather resistance, it is recommended to hydrogenate 80% or more, preferably 90% or more.

As the terminator, a known terminator capable of deactivating a living polymer produced by an organolithium compound, such as a compound having active hydrogen, can be used. Furthermore, it is also possible to terminate the reaction by introducing a functional group to the terminal end by utilizing the reaction with the active terminal group of the living polymer, or by coupling a plurality of polymers. Moreover, these can also be used together. The former terminator is preferably water, alcohol (methanol, ethanol, propatool, heptatool, etc.), polyhydric alcohol (ethylene glycol, propylene glycol, glycerin, etc.), primary amine, secondary amine, and It is a mixture of these.

In addition, as a terminator for the latter reaction, halogen compounds such as silicon tetrachloride, tin tetrachloride, methyl silicon trichloride, dibutyltin dichloride, triphenyltin chloride, etc.
Epoxy compounds, such as polyepoxy compounds such as tetraglycidyl metaxylene diamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, diglycidylaniline, ethylene oxide, propylene oxide, etc., and other carboxylic acid esters, Coupling agents include polybasic acid esters, polybasic acid anhydrides, polyfunctional isocyanates, polyfunctional aldehydes, polyfunctional ketones, and polyvinyl aromatic compounds.

Among these, particularly preferred are water and alcohol as the former terminator, and polyepoxy compounds as the latter terminator. In addition, these terminators must be used in sufficient amounts to substantially deactivate the living polymer, and the total amount of single or multiple compounds should be 1 equivalent or more, preferably 1 equivalent or more per active lithium atom. 1.1~to, ooo equivalent,
More preferably, 1.2 to 1.000 equivalents are used. If the latter reactive terminator is used, the latter should preferably be added first to allow the reaction to take place, and then the former terminator should be added.

If an effective terminator is not used, abnormal coloration and decreased stability will occur.

The monophenol type antioxidant (A) having a molecular weight of 250 or less used in the present invention is preferably di-t-butylphenol or the like.

The monophenolic antioxidant (B) with a molecular fit of 300 or more used in the present invention preferably has a general formula in which R-R5 is hydrogen, a hydrocarbon group, or a hydrocarbon containing ether, ester, thioether, or thioester. At least one of R1 and R5 has a substituent having 4 or more carbon atoms. Specifically, for example, alkyl, cycloalkyl, aryl, alkylaryl, arylalkyl, alkyloxy, aryloxy, alkylthio, arylthio, alkylthioalkyl, -
RCOOR', -ROCOR' (However, R, R'
is an alkyl or aryl group). Particularly preferred compounds include 2.6-di-t-butyl-4-methylphenol, 2.6-di but R1□ to R15 in the formula
is hydrogen, a hydrocarbon group, or a hydrocarbon group including ether, ester, thioether, thioester, and R1
At least one of □ and R15 has a substituent having 4 or more carbon atoms. Specifically, for example, alkyl, cycloalkyl, aryl, alkylaryl, arylalkyl, alkyloxy, aryloxy, alkylthio, arylthio, alkylthioalkyl, -RCO
OR'-ROCOR' (where R and R' are alkyl or aryl groups), and the like.

Among the above, preferred are monophenol type antioxidants with a molecular ff of 1350 or more, particularly preferred are:
n-octadecyl-5-(3°,5°-di-t-butyl-4'-hydroxyphenyl)propionate, 2-
t-butyl-6-(5'-t-butyl-2'-hydroxy-5'-methylbenzyl)-4-methylphenylacrylate, 2,4-bis[(octylthio)methyl]-〇-cresol, etc. .

In the present invention, an organic carboxylic acid (C) in which the number of carbon atoms in the molecule divided by the number of carboxyl groups is 8 to 30 is used. If this value is lower than this range, the affinity between the organic carboxylic acid and the rubber-like conjugated diene polymer will decrease, resulting in cloudiness, easy separation, and decreased dynamic stability. On the other hand, when this value is high, the color tone deteriorates. More preferably this value is 10-20. Furthermore, saturated fatty acid carboxylic acids are more preferred. Specifically, caprylic acid, capric acid, lauric acid, myristic acid, pentadecylenic acid,
Palmitic acid, margaric acid, stearic acid, araxic acid, behenic acid, montanic acid, oleic acid, ε-phenylcaproic acid, nonylbenzoic acid, octadecane-1,
These include 18-dicarboxylic acid, octacosane-1,28-dicarboxylic acid, coconut oil fatty acid, and beef tallow fatty acid.

In the present invention, the monophenol type antioxidant (A) with a molecular weight of 250 or less and the monophenol type antioxidant (B) with a molecular weight of 300 or more are used in the amount of the antioxidant (A) added to 100 parts by weight of the polymer. When a is part by weight and the amount of antioxidant (B) added is 5 parts by weight, a:b is LO
: Used in a ratio of 1 to 1:2, (a + b) is 0.1 to 3, and a is 2 or less, and the number of carbon atoms in the molecule divided by the number of carboxyl groups is 8 to 30. The organic carboxylic acid (C) is used in an amount of 0.01 to 0.5 equivalents to the lithium atom of the organic lithium compound used as an initiator.

Outside the above range, the effect of the present invention is that the color tone is good,
It is not possible to obtain a rubbery diene polymer composition having extremely excellent dynamic stability and static stability. Note that dynamic stability refers to the rubber-like stability under conditions in which multiple radicals are generated in a relatively short period of time during kneading under high temperature conditions in Expeller, Expander 1, other processing machines, and extruders. Stability refers to the stability of diene polymers against gelation and cracking, and static stability refers to the stability of diene polymers against gelation and lysis.Static stability refers to the stability of diene polymers against gelation and lysis. Refers to stability against

When the a:b ratio deviates from 10:1 and b becomes relatively small, static stability decreases, and when the ratio a:b deviates from 1:2 and a becomes relatively small, dynamic stability decreases. a:b is preferably in the range of 5:1 to 1:1, more preferably 4
:1 to 1.2:1 [(1/2)a+b)
If it is less than 0.1, either the dynamic stability or the static stability will decrease, and if it is more than 3, the color tone will decrease. (a+b)
preferably ranges from 0.15 to 2, more preferably from 0.2 to 1. Further, a must be 2 or less; if a exceeds 2, not only the color tone will deteriorate, but also the antioxidant (A) will volatilize, causing problems such as causing a bad odor during finishing. More preferably, a is 1 or less. If the amount of the organic carboxylic acid is less than 0.01 equivalent relative to the lithium atom of the organolithium compound used as an initiator, the color tone will deteriorate, while if it exceeds 0.5 equivalent, the dynamic stability will decrease.

Preferably it is 0.02 to 0.4 equivalent, and 0.05 to 0
．． 3 equivalents is more preferred.

In the present invention, the order of adding the terminator, antioxidant (A), antioxidant (B), and organic carboxylic acid (C) may be either simultaneous or sequential. However, if the terminator is added after other additives, the color tone may deteriorate and unexpected reactions such as coupling may occur, which is not preferable. More preferably, these are added at the same time, or after the terminator is added first, the antioxidant (A), the antioxidant (B), and the organic carboxylic acid (C) are added simultaneously.

Various commonly used methods can be used to recover the polymer of the present invention.

For example, methods for recovering the polymer by directly heating the polymer solution with a drum dryer, hot roll, thin film evaporator, etc. and evaporating the solvent under reduced pressure in some cases, or methods for recovering the polymer by steam stripping, etc. Disperse in water or hot water, evaporate the solvent by blowing in steam, then dehydrate and dry.Alternatively, after evaporating a part of the solvent in a flash tower etc., the remaining solvent is further removed in a vent extruder etc. There are ways to remove it. Particularly preferred among these is the steam stripping method. Note that in steam stripping, the pH of hot water may or may not be controlled. However, if hydrochloric acid ions, sulfate ions, phosphate ions, or sodium ions are added unnecessarily for pH control, problems such as decreased color tone, cloudy rubbery polymers, and corrosion of equipment may occur. So I don't like it. In the present invention, the desired rubbery polymer can be sufficiently obtained during steam stripping even under high pH conditions, for example, over pH 10.

The volatile content of the polymer recovered by these methods is usually preferably 1 wt% or less, more preferably o, svt.
% or less.

[Effects of the Invention] The rubber-like polymer obtained by the method of the present invention has a good color tone and does not become colored even when stored for a relatively long time in a dry or high-humidity condition such as in a high-temperature warehouse or ship hold. It has extremely excellent stability both in terms of dynamic stability and static stability. Therefore, the rubbery polymer composition of the present invention can be used as a toughening agent for impact-resistant resins, tires,
It is suitably used in vulcanized rubber applications such as footwear and industrial goods, and other rubber applications, and has characteristics that make it particularly suitable as a raw material for high-impact polystyrene resins.

[Example] EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Examples 1 to 3 1.3-Butadiene was continuously polymerized using butyl lithium in a hexane solvent, and a terminator was added to the obtained polybutadiene solution, and then an antioxidant (A), an oxidation Inhibitor (B) and organic carboxylic acid were added, the solvent was removed by steam stripping, and the obtained crumb was dried in a dehydrator and a hot air dryer to obtain a rubbery polymer. Table 1 shows the types and types of butyllithium, terminator, antioxidant, and organic carboxylic acid used.

Next, the Mooney viscosity and volatile content of the obtained polymer were measured, and the color tone was confirmed, followed by a discoloration acceleration test in dry and wet states, a dynamic stability test using a Brabender, and a static test in an oven. Conducted stability tests and
evaluated. The results are shown in Table 2.

(Left below) In Table 1, phm represents parts by weight of feed per 100 parts by weight of monomer, and phr represents parts by weight of feed per 100 parts by weight of rubber.

The antioxidants are as follows.

0BHPP: n-octadecyl-5-(3°, 5° di-t-butyl-4'-hydroxyphenyl)propionate.

BHBPA: 2-t-butyl-6-(5't-butyl~2'-hydroxy-5'-methylbenzyl)-
4-Methylphenyl acrylate.

BOTMC: 2.4-bis[(octylthio)methyl]
-o-cresol.

(Left below) In Table 2, Mooney viscosity is L rotor 2rpa+
, is the value under the condition of 100° C., and the rubber color tone is indicated by the b* value (Bestar) measured by a colorimetric colorimeter manufactured by Nippon Shinshoku Kogyo Co., Ltd. (a small value is preferable).

Dry discoloration is the color tone after 40 minutes in an oven at 150°C, and wet discoloration is the color tone after 60 minutes at 60°C and 70% humidity. Dynamic stability test at Brabender 150
The gelation time from the lowest torque to the point when the torque increases by 10% is shown under the conditions of 75 rpm (a long time is preferable). Static stability test in 150℃ oven for 40
It is expressed as the amount of gel produced after minutes (a small amount is preferred).

Comparative Examples 1 to 14 Polymers were obtained in the same manner as in Example 1 using the formulations shown in Table 3.

Table 4 shows the analytical values and evaluation results of the obtained polymer.

(Leaving space below) Examples 4 to 5 1,3-Butadiene and styrene were continuously polymerized using butyllithium in a hexane solvent according to the formulation shown in Table 5, and in the same manner as in Example 1, butadiene-styrene random Copolymerization was obtained.

Table 6 shows the analytical values and evaluation results of the obtained polymer.

Example 6 1.3-bis(N,N-diglycidylaminomethyl)cyclohexane was added to a living polybutadiene solution obtained by continuous polymerization of 1.3-butadiene to add 0.0.0% glycidyl group per molecule of active lithium. After continuously adding and mixing an amount equivalent to 7 equivalents to perform coupling, 5 phr of water as a stopper, antioxidant (A), antioxidant (B)
Polybutadiene was obtained in the same manner as in Example 1 by simultaneously and continuously adding and mixing carboxylic acid and °H carboxylic acid to an in-line mixer and mixing the mixture as shown in Table 5.

Table 6 shows the analytical values and evaluation results of the obtained polymer.

Table 6 The color tone of the obtained HIPS is as shown below in Example 7.
was the best.

Indicates b* value.

(Left below) Example 7 and Comparative Examples 15 to 1B Using the polybutadiene obtained in Example 1, impact-resistant polystyrene was obtained under the composition and temperature conditions shown in Table 7 (Example 7). Next, impact-resistant polystyrene was similarly obtained using the polybutadiene obtained in Comparative Examples 1 and 3 (Comparative Example 1
5 and 16).

There was no difference in the polymerization rate of these polystyrenes, which was an excellent result with a score in Table 7. Furthermore, the impact-resistant polystyrene obtained using this rubbery polymer composition had extremely good color tone.

On the other hand, in comparative examples that did not use the method of the present invention, the color tone of the obtained rubbery polymer composition was inferior, but the coloring progressed in the coloring acceleration test or gelation in the dynamic stability test. The results of either test were poor due to short time (either poor dynamic stability or large gel formation in the static stability test).

Claims (1)

[Scope of Claims] 1. A rubber-like polymer obtained by polymerizing a conjugated diene or a conjugated diene and a vinyl aromatic hydrocarbon using an organolithium compound as an initiator, and (A) a monophenol type antioxidant with a molecular weight of 250 or less. (B) a monophenol type antioxidant having a molecular weight of 300 or more, and (C) an organic carboxylic acid having a value obtained by dividing the number of carbon atoms in the molecule by the number of carboxyl groups from 8 to 30, into a rubber-like polymer 10
When component (A) is a part by weight and component (B) is part by weight per 0 part by weight, a:b is a ratio of 10:1 to 1:2, and [(1/2)a+b] is 0.1 to 3, and a is 2
A stabilized rubbery diene polymer composition containing component (C) in an amount of 0.01 to 0.5 equivalents based on the lithium atoms in the rubbery polymer, which is in the following range. 2. To a solution of a rubbery polymer obtained by polymerizing a conjugated diene in an inert hydrocarbon solvent using an organolithium compound as an initiator or copolymerizing a conjugated diene and a vinyl aromatic hydrocarbon, 1) Termination. 2) A monophenol type antioxidant with a molecular weight of 250 or less (
A) and 3) a monophenol type antioxidant with a molecular weight of 300 or more (
B) and 4) an organic carboxylic acid (C) whose number of carbon atoms in the molecule is divided by the number of carboxyl groups is 8 to 30, and the amount of antioxidant (A) added to 100 parts by weight of the polymer is a weight. parts and the amount of antioxidant (B) added is b weight parts, a:b
is in the ratio of 10:1 to 1:2, [(1/2)a+b] is in the range of 0.1 to 3, and a is in the range of 2 or less, and the lithium atom of the organolithium compound used as an initiator is On the other hand,
A method for producing a stabilized rubbery diene polymer composition, which comprises adding the organic carboxylic acid (C) in an amount of 0.01 to 0.5 equivalents and then recovering the polymer.