JPH01135801A - Production of modified polymer - Google Patents

Abstract

PURPOSE:To obtain a modified polymer having excellent color tone, transparency, resistance to devitrification and heat discoloration, by adding a stabilizer to a solution of a terminal modified polymer, containing polar atomic groups bound to the polymer chain ends and prepared by a specified method and contacting gaseous carbon dioxide with the resultant polymer solution. CONSTITUTION:A conjugated diene (e.g., 1,3-butadiene or isoprene) or an aromatic vinyl hydrocarbon (e.g., styrene) or both are polymerized in a hydrocarbon solvent (e.g., butane, cyclopentane or benzene) in the presence of an organolithium compound (e.g., ethyllithium or n-propyllithium) as an initiator and the resultant polymer is reacted with a polar group-containing compound (e.g., compound having -COOH- or -CO). A stabilizer or further a terminator are added to the obtained solution of a terminal modified polymer having polar group-containing atomic groups bonded to one or more polymer chain terminals or hydrogenated polymer thereof and gaseous carbon dioxide in amount of >=0.01pt.wt. based on 100pts.wt. polymer is then brought into contact with the resultant polymer solution in the presence or absence of water in an amount of <=0.5pt.wt. based on 100pts.wt. polymer to provide a modified polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a modified polymer having excellent color tone, transparency, resistance to devitrification, and resistance to heat discoloration.

[Conventional technology]

Block copolymers consisting of conjugated dienes and vinyl aromatic hydrocarbons are transparent and have the same properties as vulcanized natural rubber or synthetic rubber without vulcanization when the vinyl aromatic hydrocarbon content is relatively low. Because it has elasticity at room temperature and has processability similar to thermoplastic resin at high temperatures, it is suitable for footwear,
It is widely used in the fields of plastic modification, asphalt, adhesives, etc. In addition, when the vinyl aromatic hydrocarbon content is relatively high, a thermoplastic resin that is transparent and has excellent impact resistance can be obtained, so its usage has increased in recent years, mainly in the food packaging container field, and its applications have also expanded. It is becoming more diverse.

However, such block copolymers have poor color tone and
The disadvantage is that the molded product exhibits a yellowish tinge. Therefore, several methods have been attempted to improve this drawback. For example, Japanese Patent Publication No. 54-2679 discloses that after adding water/carbon dioxide/phenolic antioxidant to a hydrocarbon solvent of an active block copolymer, the solvent is treated at a temperature in the range of 150 to 200°C. Direct desolvation method is described.
Japanese Patent Publication No. 55-7459 describes a method in which a hydrocarbon solution of a block copolymer is heated or mixed with heated water and brought into contact with an aqueous solution of an organic acid compound before stripping the solvent. Also, Japanese Patent Publication No. 58-16861
Publication No. 2 describes a method for recovering the polymer by adding boric acid to the polymer and then adding a stabilizer.

[Problems to be solved by the invention]

However, although these methods improve the color tone, they are still insufficient and have problems such as poor transparency, resistance to devitrification, and resistance to heat discoloration.

Under such current circumstances, the present inventors have been working on color tone, transparency,
As a result of studying methods to obtain polymers with excellent resistance to devitrification and heat discoloration, we found that by adding a stabilizer, or a stabilizer and a stopper to the polymer solution, no more than a certain amount of water can be extracted. It was discovered that the purpose could be achieved by bringing a specific amount of carbon dioxide gas into contact with the subject under certain conditions or in the absence of water, and filed an application in Japanese Patent Application No. 1984-284416. Thereafter, the present inventors reacted a polar group-containing compound to the active end of the polymer, and when using a terminal-modified polymer etc. in which a polar group-containing atomic group was bonded to at least one polymer chain end, The present inventors have discovered that such improved effects can also be achieved, and have completed the present invention.

[Means of problem solving]

That is, the present invention involves reacting a polar group-containing compound with a polymer obtained by polymerizing a conjugated diene and/or a vinyl aromatic hydrocarbon using an organolithium compound as an initiator in a hydrocarbon solvent, and initiating at least one polymer. a) Add a stabilizer, or a stabilizer and a terminator to a solution of a terminally modified polymer in which a polar group-containing atomic group is bonded to the end of the combined chain or a hydrogenated product of the polymer, and then add to 100 parts by weight of the polymer. b) A polymer characterized by contacting 0.01% by weight or more of carbon dioxide gas with respect to 100 parts by weight of the polymer in the presence of 0.5 parts by weight or less of water or in the absence of water. Concerning the manufacturing method.

The present invention will be explained in detail below.

In the method of the present invention, first, a conjugated diene and/or a vinyl aromatic hydrocarbon is polymerized in a hydrocarbon solvent using an organolithium compound as an initiator to produce a polymer solution. Polymers of conjugated dienes or vinyl aromatic hydrocarbons can be produced by any known method, such as cyanionic polymerization of conjugated dienes or vinyl aromatic hydrocarbons with an organolithium compound in an inert hydrocarbon solvent. It can be manufactured by

When using conjugated diene and vinyl aromatic hydrocarbon monomers, the composition ratio of conjugated diene and vinyl aromatic hydrocarbon in the resulting polymer is not particularly limited, but is generally 99.9.
: 0.1-0.1 : 99.9, preferably 98
:2 to 5:95.

The polymer consisting of a conjugated diene and a vinyl aromatic hydrocarbon may be a random copolymer or a block copolymer, and can be prepared by any known method in an inert hydrocarbon solvent. It can be produced by cyanionic polymerization with a lithium compound.

For example, random copolymers can be made by feeding a mixture of a conjugated diene and a vinyl aromatic hydrocarbon to a polymerization vessel at a slower than normal polymerization rate, as described in U.S. Pat. No. 3,094,514. . Alternatively, as described in U.S. Pat. No. 3,451,988, a random copolymer is produced by copolymerizing a mixture of a conjugated diene and a vinyl aromatic hydrocarbon in the presence of a polar compound or a randomizing agent, which will be described later. be able to.

On the other hand, methods for producing block copolymers include, for example, Japanese Patent Publications No. 36-19286 and Japanese Patent Publication No. 43-17979.
Publication No. 46-32415, Special Publication No. 49-
Examples include the methods described in Japanese Patent Publication No. 36957, Japanese Patent Publication No. 48-2423, Japanese Patent Publication No. 48-4106, Japanese Patent Publication No. 28925-1982, Japanese Patent Publication No. 49567-1987, and the like. By these methods, block copolymers have the general formula: (A-B)n, A(-B-A)n, B-(-A-B)
n-(In the above formula, H is a polymer block mainly composed of vinyl aromatic hydrocarbons, and B is a polymer block mainly composed of conjugated dienes. The boundary between A block and B block is not necessarily clear. There is no need to distinguish between the two. Also, n is 1
is an integer greater than or equal to ) or the general formula, ((B-A-SeX, [(A-B)fliπX[(B-person-B+Trx, ((person-B)n It is obtained as a block copolymer represented by the same formula, X represents a residue of an initiator such as a polyfunctional organolithium compound, m and n are integers of 1 or more.

In the above formula, the polymer block mainly composed of vinyl aromatic hydrocarbons refers to a copolymer block of vinyl aromatic hydrocarbons and conjugated diene containing 50% by weight or more of vinyl aromatic hydrocarbons and/or vinyl It refers to an aromatic hydrocarbon homopolymer block, and a polymer block mainly composed of conjugated diene refers to a copolymer block of a conjugated diene and a vinyl aromatic hydrocarbon containing a conjugated diene in an amount exceeding 50% by weight. Or a conjugated diene homopolymer block.

The vinyl aromatic hydrocarbons in the copolymer block may be uniformly distributed or tapered. Further, the copolymer portion may include a plurality of portions in which vinyl aromatic hydrocarbons are uniformly distributed and/or a plurality of portions in which vinyl aromatic hydrocarbons are distributed in a tapered manner.

The block copolymer thus obtained exhibits properties as a thermoplastic elastomer when the content of vinyl aromatic hydrocarbon is 60% by weight or less, preferably 55% by weight or less,
When the vinyl aromatic hydrocarbon content exceeds 60% by weight, preferably 65% by weight or more, it exhibits properties as a thermoplastic resin.

The vinyl aromatic hydrocarbons used in the method of the present invention include styrene, O-methylstyrene, p-methylstyrene, p-methylstyrene,
Examples include -1art-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, and vinylanthracene, and styrene is particularly suitable for boat fishing.

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),
2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, etc., but especially -
1,3-butadiene and isoprene are listed as examples of those caught on a boat. These may be used not only alone, but also as a mixture of two or more.

Hydrocarbon solvents include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane, isooctane, etc., alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methyl 7-chlorohexane, ethylcyclohexane, etc. Aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene can be used. These may be used not only alone, but also as a mixture of two or more. Organolithium compounds are organic monolithium compounds in which one or more lithium atoms are bonded in the molecule, such as ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, 5
Examples include ec-butyllithium, tart-butyllithium, hexamethylene dilithium, butadienyldilithium, and isoprenyldilithium. These may be used not only alone, but also in combination of two or more.

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 dibutyl ether, diethylene glycol dibutyl ether. As aminos, in addition to tertiary amines such as trimethylamine, triethylamine, and tetramethylethylenediamine, cyclic tertiary amines can also be used. Phosphines and phosphoramides include triphenylphosphine and hexamethylphosphoramide. Randomizing agents include potassium or sodium alkylbenzene sulfonates, potassium or sodium butoxide.

The polymerization temperature for producing the polymer in the method of the invention is generally from -10°C to 150°C, preferably from 40°C to 120°C. Although the time required for polymerization varies depending on the conditions, it is usually within 48 hours, and particularly preferably 1 to 10 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 the external pressure is 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 s, ooo to 5,000,000, preferably io
, oo.

~1,000,000. Also, the amount of hydrocarbon in the polymer solution is generally 100! 50 per part
Parts by weight to 2000 parts by weight. 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.

The polymer obtained as described above is reacted with a polar group-containing compound at the active end of the polymer to produce a terminal-modified polymer in which a polar group-containing atomic group is bonded to at least one polymer chain terminal. Here, the polar group-containing atomic group refers to nitrogen, oxygen,
An atomic group containing at least one atom selected from silicon, phosphorus, sulfur, and tin. Specifically, carboxyl groups, carbonyl groups, thiocarbonyl groups, acid halogens (
t [F group, acid anhydride group, carboxylic acid group, thiocarboxylic acid group, aldehyde group, thioaldehyde group, carboxylic ester group, amide group, sulfonic acid group, sulfonic ester group, phosphoric acid group, phosphoric ester group , amine group, imino group, nitrile group, pyridyl group, quinoline group, epoxy group,
Examples include atomic groups containing at least one polar group selected from a thioepoxy group, a sulfide group, an incyanate group, an isothioneanate group, a silicon halide group, an alkoxy silicon group, a tin halide group, an alkyltin group, a phenyltin group, etc. It will be done. Specifically, the patent application 1986-
The terminal-modifying agent described in No. 129179 can be used, and the terminal-modifying agent described therein is within the scope of the present invention. The terminal modifying agent for imparting the polar group-containing atomic group is used in an amount of 0.5 to 2 moles, preferably 0.7 to 1 mole, per 1 atomic equivalent of lithium metal at the polymer terminal.
3 moles are used.

Further, in the present invention, the polymer obtained above can be partially or selectively hydrogenated by a hydrogenation reaction (hydrogenation reaction). 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, 75%
It is recommended to hydrogenate less than 80%, preferably 90% or more in order to improve heat deterioration resistance and weather resistance. In this case, the aromatic double bond based on the vinyl aromatic compound copolymerized into the polymer block B mainly consisting of a vinyl aromatic compound and, if necessary, the polymer block B mainly consisting of a conjugated diene compound. There is no particular limit on the addition rate, but the hydrogen addition rate is 20%.
% or less. The amount of unhydrogenated aliphatic double bonds contained in the hydrogenated block copolymer can be easily determined using an infrared spectrometer, nuclear magnetic resonance apparatus, or the like.

Catalysts used in the hydrogenation reaction include (1) Nl, Pt
, Pd, Ru and other metals to carbon, silica, alumina,
A so-called Ziegler type catalyst using a supported heterogeneous catalyst supported on a carrier such as diatomaceous material, (2) an organic acid salt such as Nl, Co, Fe, Or, or an acetylatonate salt, and a reducing agent such as organic Aλ. , or Ru, Rh
There are known homogeneous catalysts such as so-called organic complex catalysts such as organometallic compounds. The specific method is
No. 8704, Japanese Patent Publication No. 43-6636, or Japanese Patent Application Publication No. 59-133203, Japanese Patent Application Publication No. 60-22
According to the method described in Publication No. 0147, hydrogenation is performed in an inert solvent in the presence of a hydrogenation catalyst to obtain a hydrogenated product,
Hydrogenated block copolymers for use in the present invention can be synthesized. At that time, the hydrogenation rate of aliphatic double bonds based on the conjugated diene compound in the block copolymer can be controlled to any value by adjusting the reaction temperature, reaction time, hydrogen supply amount, catalyst amount, etc. It is.

A stabilizer or a stabilizer and a terminator are added to the polymer solution obtained above (step (a)). Adding these at this stage is effective in preventing oxidative deterioration and thermal deterioration of the polymer when the solvent is removed in the next step. These may be added to the polymer solution as they are, or may be added after being dissolved in a hydrocarbon solvent. As a stabilizer,
Any of the known stabilizers that have been used conventionally may be used, and various known antioxidants such as phenol-based, organic phosphate-based, organic phosphite-based, amine-based, and sulfur-based antioxidants are used. The stabilizer is generally used in an amount of 0.001 to 10 parts by weight per 100 parts by weight of the polymer. Compounds having active hydrogen can be used as terminators, but suitable ones include water, alcohols (methanol, ethanol,
propatool, etc.), polyhydric alcohols (ethylene glycol, fluoropylene gellicol, glycerin, etc.), primary amines, secondary amines, and mixtures thereof. These are generally 0.01 to 10 parts by weight per 100 parts by weight of the polymer.
It is used in an amount of 0.05 to 5 parts by weight, preferably 0.05 to 5 parts by weight. The terminator may be added before adding the stabilizer, or may be added at the same time as the stabilizer. Note that it is not preferable to use a large amount of water as a quenching agent because it deteriorates transparency and devitrification resistance. Therefore, when water is used as a deactivator, the amount is 5 parts by weight or less, preferably 3 parts by weight or less, based on 100 parts by weight of the polymer. It is recommended that the amount be less than equimolar, preferably A mol or less, based on the organolithium compound used in the polymerization.

In the present invention, treatment with acid or alkali may be performed in step (,). Note that the treatment with acid or alkali may be performed after the terminal modification reaction, if necessary. Inorganic acids used in the present invention include chlorine, sulfur, nitrogen,
Acids formed by bonding nonmetal-containing acid groups such as linkers with hydrogen, such as hydrochloric acid, sulfuric acid, nitric acid, boric acid, phosphoric acid, and carbonic acid, can be cited. Further, the organic acid used in the present invention is an organic compound having acidity in a broad sense, and includes compounds such as carboxylic acid, sulfonic acid, sulfinic acid, and phenol, but preferably an organic compound containing a carboxyl group. The following are preferred.

(1) Fatty acid having 8 or more carbon atoms (2) Rosin acid (3) Oxycarboxylic acid (4) Aromatic carboxylic acid Specific examples of fatty acids preferably used in the present invention include octylic acid, capric acid, lauric acid, and myristic acid. Examples include palmitic acid, stearic acid, oleic acid, linoleic acid, linuric acid, ricinoleic acid, behenic acid, tallow fatty acid, or mixtures thereof. Rosin acid may also be a hydrogenated product thereof. Examples of oxycarboxylic acids include compounds having at least one hydroxyl group and at least one carboxyl group in the molecule, such as glycolic acid, lactic acid,
Examples include tartaric acid, citric acid, malic acid, oxyvaleric acid, 2-hydroxystearic acid, salicylic acid, O-oxycinnamic acid, and mixtures thereof. Examples of aromatic carboxylic acids include benzoic acid, chlorobenzoic acid, aminobenzoic acid, cinnamic acid, phenylacetic acid, and mixtures thereof. The amount of these acids added is generally 0.01 to 0.5 parts by weight, preferably 0.03 to 0.3 parts by weight, per 100 parts by weight of the polymer.

Next, after adding a stabilizer or a stabilizer and a terminator to the polymer solution, 0.5 parts by weight or less, preferably 0.3 parts by weight or less, more preferably 0. 1
Contact with carbon dioxide gas in the presence of water or in the absence of water, preferably less than 1 part by weight, preferably less than 1 mole of water, more preferably 1 mole or less, relative to the organolithium compound used for polymerization. (Step (b)). The presence of water exceeding 0.5 parts by weight is not preferable because it deteriorates transparency and devitrification resistance.

The amount of carbon dioxide used is 0 per 100 parts by weight of the polymer.
．． 01 parts by weight or more, preferably 0.03 to 10 parts by weight,
More preferably, it is 0.3 to 3 parts by weight. When the amount of carbon dioxide gas is less than 0.01 part by weight, color tone, heat discoloration resistance,
This is not preferable because the coloring property of the pigment is poor.

The carbon dioxide gas used may be in solid form as dry ice or in gaseous form.

When bringing the polymer into contact with carbon dioxide gas, the solvent may be removed from the polymer solution after adding carbon dioxide gas to a stabilizer or a polymer solution containing a stabilizer and a terminator. The recommended method is to remove the solvent from the sample and then contact it with carbon dioxide gas. At this time, the amount of solvent remaining is 10% of the polymer.
In order to obtain a polymer with excellent devitrification resistance, it is preferable to remove the amount to 30 parts by weight or less, preferably 10 parts by weight or less, based on 0 parts by weight. The solvent may be removed from the polymer solution by any known method, such as heating the solution to evaporate the solvent, dispersing the solution in water or hot water, and blowing water vapor to evaporate the solvent. stripping method), a method in which a large amount of a precipitant such as methanol is added to precipitate the polymer and separate it from the solvent, a method in which the solution is vacuum-dried, a method in which a part of the solvent is evaporated in a flash tower, etc., and then further A method such as removing the solvent using a vented extruder can be adopted.

Although the method of bringing the polymer obtained by removing the solvent from the polymer solution into contact with carbon dioxide gas in the presence of water or in the absence of water is not particularly limited, a preferred method is to contact carbon dioxide gas with the polymer obtained by removing the solvent from the polymer solution. Examples include a method of bringing the polymer into contact with the polymer in a gas or a carbon dioxide-containing gas (air, nitrogen, helium, argon, etc.), and a method of supplying carbon dioxide and the polymer into a conventionally known mixer and kneading them. As the mixer, an open roll, an inch mixer, an internal mixer, a co-kneader, a continuous kneader with a twin-screw rotor, a -shaft, twin-screw or multi-screw extruder, etc. are used. The recommended contact time between carbon dioxide gas and the polymer is 0.1 seconds to about 1 month, preferably 1 second to about 1 week. In addition, in the method of the present invention, if it is desired to further remove the solvent remaining in the polymer after contacting with carbon dioxide gas, it can be removed by adopting any of the solvent removal methods described above. good.

The most preferred embodiment of the method of the present invention is (1) to reduce the amount of residual solvent in the multipolymer by heating and evaporating the solvent from a polymer solution to which a stabilizer or a stabilizer and a terminator have been added, or by a steam stripping method. A method in which the amount is reduced to 5% by weight or less, preferably 1% by weight or less based on 100 parts by weight of the combined product, and then carbon dioxide is added and kneaded in an extruder (including a vented extruder); In this method, a part of the solvent is evaporated in a flash tower from a polymer solution to which an agent and a terminator have been added, and then the remaining solvent is further removed in a vented extruder to recover the polymer. The amount of polymer is 1
A method in which carbon dioxide is added in a step in which the amount is 5 parts by weight or less, preferably 1 part by weight or less, based on 00 parts by weight; ■Stabilizer;
Or, remove the solvent from a polymer solution containing a stabilizer and a terminator by heat evaporation, steam stripping, vent extrusion, etc. to reduce the amount of residual solvent in the multipolymer to 5 parts by weight per 100 parts by weight of the polymer. 1 part by weight or less, preferably 1 part by weight or less, and then allowed to stand in nitrogen gas or air containing a predetermined amount of carbon dioxide gas.

Various additives can be added to the polymer obtained by the method of the present invention depending on the purpose.

For example, softeners such as oil, plasticizers, antistatic agents, lubricants, ultraviolet absorbers, flame retardants, pigments, inorganic fillers, organic and inorganic fibers, reinforcing agents such as carbon black, and other thermoplastic resins. Can be used as an additive. The polymer obtained by the method of the present invention does not have problems such as color change due to the addition of additives, such as yellowing due to the addition of ultraviolet absorbers, abnormal color tone due to the addition of pigments, etc., and therefore cannot be used with various additives. By using a wide range of combinations with

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

The block copolymers used in the examples were produced as follows. The weight ratio of polymer to solvent in each of the obtained polymer solutions was 1:4.

[Block copolymer (4)] In a nitrogen gas atmosphere, n-hexane solution containing 15 parts by weight of 1,3-butadiene and 20 parts by weight of styrene was added.
- After adding 1 m part of butyllithium and polymerizing at 70°C for 2 hours, further adding an n-hexane solution containing 45 parts by weight of 1.3-butadiene and 20 parts by weight of styrene, and polymerizing at 70°C for 2 hours. Polymerized for hours. The obtained polymer was a block copolymer having a B-A-B-A structure with a styrene content of 40% by weight.

[Block copolymer (B)]

In a nitrogen gas atmosphere, 0.11 parts by weight of n-butyllithium was added to a cyclohexane solution containing 15 parts by weight of styrene, and after polymerization at 70°C for 1 hour, a cyclohexane solution containing 70 parts by weight of 1,3-butadiene was added. The mixture was added and polymerized at 70°C for 2 hours. Thereafter, a cyclohexane solution containing 15 parts by weight of styrene was further added, and polymerization was carried out at 70° C. for 1 hour. The obtained polymer was a block copolymer having a human-B-A structure with a styrene content of 30% by weight.

[Block copolymer (C)]

In a nitrogen gas atmosphere, 0.08 heavy chain parts of n-butyl lithium was added to a cyclohexane solution containing 30 heavy chain parts of styrene and 0.3 i bone parts of tetrahydro-7r).
After polymerizing for 1 hour at 0°C, 1,3-butadiene 20
A cyclohexane solution containing 50 parts by weight of styrene and 50 parts by weight was added and polymerized at 70°C for 2 hours. The obtained polymer was a block copolymer having an ABA structure with a styrene content of 80% by weight.

[Block copolymer (D)]

In a nitrogen gas atmosphere, n-hexane solution containing 15 parts by weight of 1,3-butadiene and 20 parts by weight of styrene was added with n.
- Add 0.07 parts by weight of butyllithium and
After polymerization for an hour, an n-hexane solution containing 15 parts by weight of 1.3-butadiene and 50 parts by weight of styrene and 0.02 part by weight of n-butyllithium were further added, followed by polymerization at 70° C. for 2 hours. The obtained polymer contains styrene! The resulting polymer solution was in the form of a suspension. .

[Block copolymer (E)]

In a nitrogen gas atmosphere, isoprenyldilithium having active lithium equivalent to 0.2 parts by weight of n-butyllithium was added to a cyclohexane solution containing 85 parts by weight of isoprene, and polymerized at 70°C for 2 hours. Then, a cyclohexane solution containing 15 parts by weight of styrene was added and the mixture was heated to 70°C.
Polymerization was carried out for 1 hour. The resulting polymer had a styrene content of 1
It was a block copolymer with 5% Human-B-A structure.

[Block copolymer (F)]

In a nitrogen gas atmosphere, n-hexane solution containing 80 parts by weight of 1,3-butadiene and 20 parts by weight of styrene was added
- Add 0.08 parts by weight of butyllithium and
Polymerized for hours. The obtained polymer was a block copolymer having a BA structure with a styrene content of 20% by weight.

Examples 1 to 4 and Comparative Examples 1 to 4 To the solution of the block copolymer (0) produced above, 4.4 molar equivalent to n-butyllithium used in the polymerization was added.
'-Dimethylaminobenzophenone was reacted to obtain a solution of a terminally modified block copolymer in which the reactive residue of the compound was bonded to the polymer terminal. To this solution, 0.5 parts by weight each of 4-methyl-2,6-tert-methylphenol and lysnonylphenyl phosphite were added as stabilizers per 100 parts by weight of the polymer. The solvent was removed by heating until the amount of residual solvent became 1 part by weight or less.

Thereafter, carbon dioxide gas was added according to the addition procedure shown in Table 1, and the mixture was extruded into pellets using a 30 mφ extruder. still,
In Example 4, carbon dioxide gas was added to a polymer solution to which a stabilizer had been added, and the mixture was thoroughly mixed, and then the solvent was similarly removed by heating to form pellets. The obtained pellet was press-molded at 180°C to create a sheet with a thickness of 2 m, and the color tone, transparency, resistance to devitrification, resistance to heat discoloration, and colorability with pigments were measured. The results are shown in Table 1. Indicated.

On the other hand, in Comparative Example 2, 1 part by weight of carbon dioxide gas and 1 part by weight of water were added to 100 parts of the block copolymer to form pellets. In addition, in Comparative Example 3, block copolymer (
Carbon dioxide gas and block copolymer 1 in an amount of 3 times the molar equivalent of lithium in n-butyllithium used in the polymerization of 0)
oo) After adding 10 parts by weight of water to the part of HR to the polymer solution, adding 0.5 part by weight of 4-methyl-2,6-tert-butylphenol to 100 parts by weight of the polymer; The solvent was removed by heating. Furthermore, in Comparative Example 4, water 2
It contains an aqueous solution in which parts by weight of tartaric acid o and oos are dissolved in 0 parts by weight, and 100 parts by weight of block copolymer (0). The stabilizer-containing polymer solution was left to stand for about 10 minutes, and then left to stand, and the separated polymer solution layer was dropped little by little onto heated water at 80 to 85°C to volatilize the solvent.

Table 1 (Note 1) Addition amount per 100 parts by weight of polymer (Note 2) Color tone was determined by measuring the b value using a comprehensive vision meter ND-V6B manufactured by Nippon Denshoku Industries Co., Ltd. The larger the b value, the greater the apparent yellowness.

b value is less than 5 ◎ b value is 5 to 100 b value is more than 10 × (Note 3) Chromaticity was measured in accordance with ASTM D-1003.

Chromaticity is less than 5 ◎ Chromaticity is 5-10 0 Haze is greater than 1O × (Note 4) After leaving the test piece in a desiccator filled with water for 7 days without direct contact with water, The chromaticity of each test piece was measured in accordance with A8TM D-1003, and the difference between the chromaticity of the test piece of each polymer obtained by adding only the stabilizer and removing the solvent was determined, and the devitrification resistance was determined. judged. The larger this difference is, the worse the devitrification resistance is.

Difference in chromaticity is less than +5 ◎ Difference in chromaticity is +5 to +15 0 Difference in cloudiness is more than +15 × (Note 5) Color tone after each polymer is left standing in air heated to 180°C for 2 hours was determined visually.

◎; Colorless to very light yellow O: Slightly yellowish ×; Yellow to brown (Note 6) lpp of Solvent Violet 13 to the polymer
m was added, and the color after melt mixing in a 30 mφ extruder was visually judged.

O: Bright blue, expressing the original color tone of the pigment.

x; dull blue to bluish green color, and the original color tone of the pigment was not expressed.

Examples 5 to 8 and Comparative Examples 5 to 8 After reacting the block copolymer pasting polymer shown in Table 2 with an equivalent molar amount of terminal treatment agent to n-butyllithium used in the polymerization, termination was performed. Each of the agents was added in an amount of 0.3 parts by weight to the loop bone of the block copolymer.

After that, benzoic acid was added in imole to the n-butyllithium used in the polymerization, and then octadecyl-
0.5 parts by weight of each of a-(a', s'-di-tert-butyl-4-hydroxyphenyl)gropionate and trisnonylphenyl phosphite were added to 100 parts by weight of the polymer, and then the remaining amount in the polymer was added. The solvent was removed by heating until the amount of solvent became 1 part by weight or less.

Thereafter, 1 part by weight of carbon dioxide gas and the polymer were extruded using a 30 mm diameter extruder per 100 parts by weight of the polymer to form pellets. In addition, in the comparative example, extrusion was performed without adding carbon dioxide gas,
It was made into pellets.

Examples 9 and 10 and Comparative Examples 9 and 10 The block copolymers shown in Table 3 were added in equivalent moles (in terms of n-butyllithium) to the lithium catalyst used in the polymerization.
After reacting with the terminal treating agent, 0.05 parts by weight of water was added as a terminator per 100 parts by weight of the block copolymer. Then, 4-methyl-2,6 was used as a stabilizer.
-After adding 0.5 parts by weight of each of sheet-tcrt-butylphenol and trisnonylphenyl phosphite to 100 parts by weight of the polymer, the solvent is removed by heating until the amount of residual solvent in the polymer is 1 part by weight or less. did. Thereafter, it was extruded into pellets or crumbs using a 30 φ extruder. After that, 0.1 parts by weight per 100 parts by weight of the polymer.
The polymer was allowed to stand for one week at room temperature in sealed air containing parts by weight of carbon dioxide. On the other hand, in the comparative example, the sample was left standing at room temperature for one week in air substantially free of carbon dioxide gas.

Below is a blank space Table 3 Example 11 In a nitrogen gas atmosphere, 0.15 parts by weight of n-butyllithium was added to a cyclohexane solution containing 15 parts by weight of styrene and 0.08 parts by weight of tetramethylethylenediamine, and polymerization was carried out at 70°C for 1 hour. After that, a cyclohexane solution containing 70 parts by weight of butadiene was added and polymerized at 70° C. for 2 hours. Thereafter, a cyclohexane solution containing 15 parts by weight of styrene was further added, and polymerization was carried out at 70° C. for 1 hour. The resulting block copolymer was reacted with 4,4'-dimethylaminobenzophenone in an equimolar amount to the n-butyllithium used in the polymerization, resulting in terminal modification in which reactive residues of the compound were bonded to the polymer terminals. A block copolymer was obtained.

Next, the terminal-modified block copolymer obtained above was hydrogenated using a rhodium-based hydrogenation catalyst described in JP-A No. 52-41690, and the hydrogenated block copolymer with a hydrogenation rate of 98% in the butadiene moiety was produced. Obtained union. Thereafter, 1 part by weight of water and octadecyl-3-(3') were added to the solution of the polymer.

0.5 part by weight of 5-tart-7'thyl-4-hydroxyphenyl)/II globionate was added, and the solvent was removed by heating until the amount of residual solvent in the polymer became 1 part by weight or less. Water content in the polymer after solvent removal is approximately 0.07% by weight
Met. Thereafter, 1 part by weight of carbon dioxide gas and the polymer were extruded using a 30 mm diameter extruder to form pellets based on 100 parts by weight of the polymer. The obtained polymer was excellent in color tone, resistance to heat discoloration, and color property of the pigment layer.

Example 12 In a nitrogen gas atmosphere, 0.07 parts by weight of n-butyllithium and 0.4 parts by weight of tetramethylethylenediamine were added to n-hexane containing 75 parts by weight of 1,3-butadiene and 25 parts by weight of styrene, Polymerization was carried out at 50°C for 6 hours. The obtained polymer was added with an equimolar amount of N based on the n-butyllithium used in the polymerization.

After reacting the N'-dimethylpropylene urea, 0.2 parts by weight of myristic acid was added. Then 4-methyl-
2,6-G-ts! After adding 1 part by weight each of rt-butylphenol and water, the polymer solution was heated to about 120°C, and the remaining solution was 20 parts by weight or less and the residual water was 0.1 part by weight or less (polymer 100 parts by weight or less). % of weight). Thereafter, 0.2 parts by weight of carbon dioxide gas was added to this polymer, and the polymer was extruded using a pent extruder, and at the same time, residual solvent and the like were removed from the pent part.

The thus obtained polymer had good color tone, transparency, and heat discoloration resistance.

Example 13 0.0.0 of n-butyllithium was added to n-hexane containing 100 parts by weight of 1.3-butadiene in a nitrogen gas atmosphere.
5 parts by weight were added and polymerized at 70°C for 4 hours.

After reacting the obtained polymer with N-methyl-ε-caprolactam in an equimolar amount relative to n-butyllithium used in the polymerization, 0.1 part by weight of benzoic acid was added. Thereafter, 1 part by weight of 4-methyl-2,6-tert-butylphenol was added, and the solvent was removed by heating until the remaining solvent became about 1 part by weight.

0.2 parts by weight of carbon dioxide gas was added to 100 parts by weight of this polybutadiene, and the mixture was kneaded for 10 minutes using an 8φ inch roll at 60° C. As a result, polybutadiene with good color tone was obtained.

Example 14 In a nitrogen gas atmosphere, n-butyllithium was added to a cyclohexane solution containing styrene and polymerized at 70° C. for 2 hours to obtain polystyrene having a weight average molecular weight of about 200,000. The obtained polymer was reacted with ethylene oxide in an amount of 1.5 times the mole of n-butyllithium used in the polymerization. Then, after adding 0.5 parts by weight of octadecyl-a-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate to 100 parts by weight of the polymer, the remaining solvent was reduced to about 1 part by weight or less. The solvent was removed by heating. 0.5 parts by weight of carbon dioxide gas was added to 100 parts by weight of this polystyrene, and the mixture was pelletized using an extruder.

The obtained pellets were extremely superior in color tone, heat discoloration resistance, and colorability with pigments compared to pellets that did not use carbon dioxide gas.

〔effect〕

The modified polymer obtained by the method of the present invention is transparent and has excellent color tone, resistance to heat discoloration, and coloring property by adding pigments, so it can be used to produce sheets, films, injection molded products of various shapes, and blow molding. It can be used for a wide variety of molded products such as molded products, pressure-formed products, and vacuum-formed products. In addition to the modified block copolymer of a conjugated diene and a vinyl aromatic hydrocarbon, the method of the present invention can also be applied to a modified block copolymer of a conjugated diene and a vinyl aromatic hydrocarbon, a modified product of a conjugated diene polymer, a vinyl aromatic hydrocarbon polymer, a conjugated diene, and a vinyl aromatic It can also be used as a modified random copolymer with hydrogen.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] 1. A polar group-containing compound is reacted with a polymer obtained by polymerizing a conjugated diene and/or a vinyl aromatic hydrocarbon in a hydrocarbon solvent using an organolithium compound as an initiator,
a) Adding a stabilizer or a stabilizer and a terminator to a solution of a terminally modified polymer in which a polar group-containing atomic group is bonded to at least one polymer chain end or a hydrogenated product of the polymer, and then In the presence of 0.5 parts by weight or less of water per 100 parts by weight or in the absence of water, b) Contacting 0.01 parts by weight or more of carbon dioxide per 100 parts by weight of the polymer. Method for producing a modified polymer