JPH0364525B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for producing a polymer modified with an olefinically unsaturated compound, and the present invention relates to a method for producing a polymer modified with an olefinically unsaturated compound, and the present invention relates to a method for producing a polymer modified with an olefinically unsaturated compound. The present invention relates to a method for producing a modified polymer that provides a method for efficiently removing and recovering unreacted olefinic unsaturated compounds.

[Prior art]

It has long been known that the modification reaction of polymers with olefinic unsaturated compounds is carried out in solution or in the molten state, and in recent years, many technical proposals have been made regarding the modification of industrially useful polymer materials and their production methods. is being done.

For example, Japanese Patent Publication No. 55-22488 proposes reacting polymers such as polyamide resins, saturated polyester resins, polycarbonate resins, polyolefin resins, and elastomers with monomers in an extruder in the presence of a radical generator.
Furthermore, Japanese Patent Publication No. 58-445 proposes reacting an olefinic rubber in the molten state with an unsaturated dicarboxylic acid or its anhydride in the presence of an organic peroxide. This kind of proposal was further proposed in Japanese Unexamined Patent Application Publication No.
-27336 Publication, JP-A-55-38803, JP-A-Sho
Also found in JP-A No. 55-50007, JP-A-55-50008, JP-A-55-60511, and JP-A-56-118411, thermoplastic resin, vinyl aromatic compound-conjugated diene system A method for making modified polymers for compound block copolymer elastomers is disclosed.

[Problem that the invention seeks to solve]

However, although the methods for producing modified polymers that are carried out in the molten state disclosed in these proposals suggest the content of modification of the polymer, they are too incomplete in terms of process to be implemented industrially. Therefore, it was not a completed method for producing modified polymers.

That is, the following problems can be mentioned in the conventional method for producing a modified polymer.

When the olefinic unsaturated compound to be reacted with the polymer is provided as a solid at ambient temperature, it is reacted in a molten state, and the unreacted olefinic unsaturated compound that does not contribute to the reaction is removed by venting under reduced pressure. When attempting to recover the compound, which has vaporized in the kneading machine, is cooled and solidified in the vent piping and recovery trap, and is further cooled and solidified in the vacuum pump, resulting in blockage of these lines, leaving substantially less unreacted olefinic unsaturated compound. It is not possible to obtain modified polymers.

In order to improve the above problem, attempts have been made to prevent the vent piping from clogging by heating and insulating the vent piping. This may cause deterioration of the liquid, which may worsen the depressurization level of the vacuum pump and make it impossible to operate.Furthermore, if the sealing liquid is water, it may migrate into the drainage water, leak out of the system, or cause serious damage. At present, there are many problems in implementing this process as a manufacturing process for modified polymers.

[Means for solving problems]

The present invention has been made in order to solve the problems associated with the above-mentioned method for producing modified polymers in a molten state. By requiring equipment and specific conditions, it is possible to efficiently remove and recover unreacted olefinic unsaturated compounds that did not contribute to the polymer modification reaction that takes place in the melt-kneading machine, and to virtually eliminate any remaining olefinic unsaturated compounds. The present inventors have discovered that the present invention is a method for producing a modified polymer with a small amount of unreacted olefinic unsaturated compounds, and has further discovered that it is an industrially useful method for producing a modified polymer.

That is, the present invention provides a method for treating a thermoplastic resin and/or a thermoplastic elastomer with a styrene compound, a methacrylic acid ester compound, a cyanated olefin compound, an acrylic acid ester, or a fatty acid vinyl ester in the presence or absence of an organic peroxide. , hydroxyalkyl group-containing (meth)acrylic acid ester, N-alkylol (meth)acrylamide, ethylenically unsaturated carboxylic acid, aminoalkyl (meth)acrylamide, epoxyalkyl ester of ethylenically unsaturated carboxylic acid, carboxylic acid anhydride In a method for producing a modified polymer in which the unreacted olefinic unsaturated compound is reacted with at least one kind of olefinic unsaturated compound selected from the following in a heated melt-kneading machine, the unreacted olefinic unsaturated compound is removed from the molten mixture by venting under reduced pressure and recovered. (1) The unreacted olefinically unsaturated compound removed by the vent is liquefied by heat exchange with a liquid heat exchange medium adjusted to a liquefying temperature, and the liquefied liquid flows into the collection trap under its own weight. A heat exchanger (2) having a structure in which the olefinically unsaturated compound in the liquid exiting the heat exchanger is continuously descended from the heat exchanger inlet to the heat exchanger outlet. This method of producing a modified polymer is characterized in that the olefinic unsaturated compound is efficiently recovered in a liquid state by connecting a device comprising the above to the vent hole of the heating melt kneader.

The present invention will be described in detail below.

Any known thermoplastic resin can be used as the thermoplastic resin used in the present invention, such as polyolefin resin, polystyrene resin, vinyl aromatic compound/conjugated diene compound block copolymer resin, poly( meth)acrylate resin,
Examples include polyamide resins, saturated polyester resins, polyphenylene ether resins, and mixtures of these resins.More specifically, polyethylene and propylene polymers are useful, and propylene alone or propylene and ethylene or a combination of carbon atoms It is a polypropylene obtained by copolymerizing at most 8 α-olefins, or a copolymer of propylene-ethylene or α-olefin, and its polymer structure may be a random copolymer or a block copolymer. May be combined. More preferred resins include vinyl aromatic compound/conjugated diene compound block copolymer resins such as styrene/butadiene block copolymer resins containing more than 60% by weight of vinyl aromatic compounds, and hydrogenated products thereof. Can be used. These resins can be used alone or in mixtures as required.

Furthermore, any known thermoplastic elastomer can be used as the thermoplastic elastomer provided in the present invention, such as polyolefin rubber, vinyl aromatic compound/conjugated diene compound block copolymer elastomer, and hydrogenated products thereof. These elastomers can be used alone or in a mixture.
More specifically, ethylene/propylene copolymer, ethylene/butene-1 copolymer, ethylene/
Olefin elastomers such as propylene/non-conjugated diene copolymers; styrene/butadiene block copolymers and polystyrene-polyisoprene having block structures such as polystyrene-polybutadiene, polystyrene-polybutadiene-polystyrene, polybutadiene-polystyrene-polybutadiene-polystyrene; Vinyl aromatic compounds/conjugated diene compounds containing 60% by weight or less of vinyl aromatic compounds, such as styrene/isoprene block copolymers having a block structure such as polystyrene-polyisoprene-polystyrene, polyisoprene-polystyrene-polyisoprene-polystyrene, etc. Block copolymer elastomers are preferably provided;
Furthermore, hydrogenated products of these block copolymer elastomers can also be preferably provided. The above-mentioned elastomers may be used alone or in the form of a mixture.

In addition, the organic peroxide that can be provided in the present invention can be used as necessary to promote the reaction between the thermoplastic resin and/or thermoplastic elastomer described above and the olefinic unsaturated compound described below. Known peroxides can be used, such as benzoyl peroxide, lauroyl peroxide, dicumyl peroxide,
α,α'-bis(t-butylperoxydiisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t- butylperoxy) hexyne-3, di-t-butyl peroxide, cumene hydroperoxide, 1,1-bis(tertiary
(butylperoxy)3,3,5-trimethylcyclohexane, t-butylhydroperoxide, and the like. The amount of organic peroxide added is not particularly limited, but if necessary, it may be added to the thermoplastic resin and/or
Or normally per 100 parts by weight of thermoplastic elastomer
It is 0.001 to 5 parts by weight.

Next, the olefinically unsaturated compound provided in the present invention reacts with a thermoplastic resin and/or thermoplastic elastomer to impart useful properties of the olefinically unsaturated compound to the resin and/or elastomer. It is an essential component of
As the olefinic unsaturated compound, known compounds can be used, such as styrene, vinyltoluene,
Styrenic compounds such as α-methylstyrene and p-tert-butylstyrene, methyl methacrylate,
Methacrylate ester compounds such as ethyl methacrylate, n-propyl methacrylate, and isopropyl methacrylate; cyanide olefin compounds such as (meth)acrylonitrile; and acrylic compounds such as methyl acrylate and butyl acrylate. Acid esters, fatty acid vinyl esters such as vinyl acetate and vinyl propionate, (meth)acrylic esters containing hydroxyalkyl groups such as 2-hydroxyethyl group and 2-hydroxypropyl group, and N-methylol ( N-alkylol (meth)acrylamide such as meth)acrylamide, and carboxyl group-containing compounds such as (meth)acrylic acid, itaconic acid,
Ethylenically unsaturated carboxylic acids such as crotonic acid and cinnamic acid, aminoalkyl (meth)acrylamides such as (meth)acrylamide and aminomethyl (meth)acrylamide as amino group-containing compounds, and (meth)allyl as epoxy group-containing compounds. Glycidyl ether or (meth)
Examples of epoxyalkyl esters of ethylenically unsaturated carboxylic acids such as acrylic acid glycidyl esters, and carboxylic acid anhydrides include (meth)acrylic anhydride, itaconic anhydride, and maleic anhydride. These olefinically unsaturated compounds can be used not only alone but also in combination of two or more.

Among these, the present invention is effective for polymer modification reactions using olefinically unsaturated compounds that are solid at room temperature, specifically at 25°C. Examples of such olefinically unsaturated compounds include maleic anhydride,
Examples include acrylamide, methacrylamide, itaconic acid, and crotonic acid.

The amount of the olefinically unsaturated compound that can be provided in the present invention is not particularly limited as it varies depending on the degree of modification of the desired modified polymer, but is usually 100 parts by weight of the thermoplastic resin and/or thermoplastic elastomer. The amount is 0.005 to 30 parts by weight.
In addition to the materials for obtaining the modified polymer described above, the present invention may also contain inorganic fillers, glass fibers, colorants, oxidation stabilizers, ultraviolet absorbers, ultraviolet stabilizers, lubricants, nucleating agents, etc., as necessary. Modification of the polymer can be carried out in the presence of various additives.

The modified polymer of the present invention can be produced by using the above-mentioned thermoplastic resin and/or thermoplastic elastomer,
Using a heated melt kneader that can vent under reduced pressure, a mixture consisting of an olefinic unsaturated compound, an organic peroxide provided as necessary, and various additives is used.
This is achieved by melt-kneading the thermoplastic resin and/or the thermoplastic elastomer under temperature conditions where the thermoplastic resin and/or thermoplastic elastomer are in a molten state and can be kneaded, and by selecting a reaction time that allows the desired reaction rate of the olefinically unsaturated compound to be obtained. The usual melt-kneading temperature is 100°C to 300°C, and the reaction time is 0.5 minutes to 1 hour.

In addition, the heating melt kneading machine used in the present invention is
It is a heated melt kneading machine equipped with a vent hole that can be vented under reduced pressure using a vacuum pump, and a single screw extruder,
Those that can perform heat-melting and kneading continuously, such as co-rotating twin-screw extruders and counter-rotating twin-screw extruders, and those that can perform heat-melting and kneading in batches, such as pressure kneaders, Banbury mixers, Brabenders, etc. You can choose any one from among them. Therefore, the above-mentioned reaction for obtaining the modified polymer of the present invention can be carried out either continuously or batchwise depending on the type of heating melt kneader used, and the unreacted olefinic unsaturated The method of venting and recovering the compound under reduced pressure using a vacuum pump can be carried out either continuously or batchwise depending on the type of heating melt kneader used.

The present invention provides a method for producing the above-mentioned modified polymer,
Furthermore, (1) the unreacted olefinic unsaturated compound removed by the vent is liquefied by heat exchange with a liquid heat exchange medium adjusted to a liquefying temperature, and the liquefied liquid is recovered by its own weight into a recovery trap. (2) a heat exchanger having a structure in which the olefinic unsaturated compound in the liquid exiting the heat exchanger is stored in a liquid state from the heat exchanger inlet to the heat exchanger outlet so as to flow into the heat exchanger; This is a novel method for producing a modified polymer, characterized in that a recovery trap is attached to the vent hole of the heating melt kneader as an essential device.

The heat exchanger provided as an essential device in the present invention is used when venting under reduced pressure gaseous unreacted olefinic unsaturated compounds remaining in the polymer modification reaction carried out in the heated melt kneader. It has the function of converting the gaseous olefinic unsaturated compound into a liquid state with low vapor pressure by connecting directly to the vent hole and exchanging heat. It is a heat exchanger having a structure such as an exchanger or a coiled tube heat exchanger, and may have the same performance as the heat exchanger. Since it is possible to change the olefinic unsaturated compound into a liquid, it is possible to reduce the amount of the olefinic unsaturated compound transferred to the vacuum pump, and eliminate operational problems such as deterioration of the sealing liquid of the vacuum pump and deterioration of the degree of vacuum. , which has a beneficial effect on production on an industrial scale.

Therefore, the heat exchanger used in the present invention takes into consideration the amount and temperature of the high-temperature gaseous olefinic unsaturated compound discharged through the vent hole, and the temperature of the liquid is such that the vapor pressure of the compound is low as desired. The structure is designed to have an effective heat transfer area such that Tm≦T≦Tm＋50℃, especially for those whose olefinically unsaturated compound exhibits solid properties at 25℃, preferably
Tm+5℃≦T≦Tm+30℃ (here, Tm is the melting point of the olefinically unsaturated compound, and T is the adjusted temperature of the heat exchange medium provided to the heat exchanger and/or the temperature of the liquefied compound. It is preferable to use a heat exchanger whose structure is designed so that Any heat exchange medium may be used in this heat exchanger, but temperature-controlled water or oil can be easily used. By adopting these conditions, the olefinically unsaturated compound, which exhibits solid properties at 25°C, can be efficiently recovered in liquid form.

Furthermore, the heat exchanger provided in the present invention has a structure in which the high temperature gaseous olefinic unsaturated compound discharged from the vent hole is successively heat exchanged in the heat exchanger, liquefied, and flows into the recovery trap by its own weight. It is preferable that the heat exchanger has a unique structure in which the flow from the inlet of the heat exchange section to the outlet of the heat exchange section is continuously descended.

Next, the recovery trap provided as an essential device in the present invention has the function of storing in a liquid state the liquid olefinic unsaturated compound that has been heat exchanged to a low vapor pressure temperature in the above-mentioned heat exchanger, and has the function of storing the liquid olefinic unsaturated compound in a liquid state, and also has a vacuum pump and a vacuum pump. It has a structure that allows connection. In order to maintain the above-mentioned functions, this recovery trap has a structure in which the temperature can be adjusted from the outside, such as a jacket, and also has a structure that also has ancillary equipment such as a buffer and a heat exchanger inside the recovery trap. You can leave it there. Any medium can be passed through the jacket, but temperature-controlled water or oil is readily available, usually at the same temperature conditions as the heat exchanger described above, but lower if necessary. It is also possible to select the temperature.

The method of use of the recovery trap of the present invention is to use a high boiling point solvent in which the liquid olefinically unsaturated compound to be recovered can be dissolved and/or a high boiling point solvent capable of reacting with the compound and promoting a reduction in the vapor pressure of the compound. It is also possible to use it by placing it inside the collection trap in advance, which can reduce the amount of the olefinic unsaturated compound transferred to the vacuum pump, and prevent deterioration of the sealing liquid of the vacuum pump and deterioration of the degree of vacuum. It can eliminate operational troubles and has a beneficial effect on industrial scale production. The high boiling point solvent that can be used here can be arbitrarily selected from known ones, such as various oils, triphenyl phosphate,
Examples include glycol and its derivatives, glycerin and its derivatives, and the like. The method of dissolving the olefinically unsaturated compound using these high-boiling point solvents and collecting it in a liquid state in a collection trap efficiently converts the olefinically unsaturated compound, which is solid at 25°C, into a liquid. This is the most useful method for collecting the waste in its original state and extracting it from the collection trap as waste, and is also preferable in terms of the working environment.

The vacuum pump connected to the collection trap should provide a vacuum of at least 600 mm Hg gauge pressure, preferably 700 mm Hg.
It is preferable to select a vacuum pump that has a pressure equal to or higher than the Hg gauge pressure.

As mentioned above, the present invention modifies a polymer with an olefinic unsaturated compound using a series of production equipment consisting of a heated melt kneader with a vent hole, a heat exchanger with liquefaction ability, a liquid recovery trap, and a vacuum pump. Furthermore, it is a method for producing a modified polymer in which residual unreacted olefinic unsaturated compounds are removed and efficiently recovered in a liquid state.

〔Effect of the invention〕

The method for producing a modified polymer provided by the present invention can stably obtain a modified polymer with a small amount of residual unreacted olefinic unsaturated compounds, reducing troubles during production and discharging them from the system. Since the present invention provides a useful production method in which unreacted olefinic unsaturated compounds are extremely reduced and improved, it can be used as an easy and efficient production method for modified polymers in industrial production.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Styrene/butadiene block copolymerization with a styrene bond content of 35% by weight (Block SBR) 100 parts by weight Maleic anhydride 5 parts by weight Stabilizer 1 part by weight were mixed in a Henschel mixer,
The modification reaction was carried out using a mmφ biaxial extruder with counter-rotating vent holes at a set temperature of 260° C. and a vent vacuum degree of 740 mmHg gauge pressure. The heat exchanger directly connected to the extruder vent hole is a double-tube heat exchanger with a descending structure from the heat exchange section inlet to the heat exchange section outlet, and the outer tube has a 60 mm diameter.
I ran warm water adjusted to ℃. Furthermore, a recovery trap with a jacket is connected to the outlet of this heat exchanger.
Warm water adjusted to 60°C was also poured into the jacket.
A water ring type vacuum pump was used as the vacuum pump and connected to one end of the collection trap.

Analysis of the pellets obtained in the modification reaction revealed that 1.3 parts by weight of maleic anhydride was grafted per 100 parts by weight of block SBR, and 0.05 parts by weight of maleic anhydride remained unreacted. In addition, unreacted maleic anhydride collected in the collection trap is
The amount is 3.6 parts by weight per 100 parts by weight of SBR, and approximately 97% of unreacted maleic anhydride that does not contribute to the reaction can be recovered as a liquid.

Comparative Example 1 Using the same raw materials as in Example 1, without using the heat exchanger of Example 1, and instead using the exhaust heat of the air that cools the cylinder of the extruder, the vent piping between the vent hole and the recovery trap was constructed. Example 1 except that a device with a double pipe structure was used to heat the outer periphery with exhaust heat.
When block SBR was modified in the same manner as above, 1.3 parts by weight of maleic anhydride was grafted per 100 parts by weight of block SBR, and 0.06 parts by weight of maleic anhydride remained as an unreacted substance. The amount of unreacted maleic anhydride recovered in the recovery trap was 1.48 parts by weight per 100 parts by weight of block SBR.
of unreacted maleic anhydride that did not contribute to the reaction.
Only 40% could be recovered in liquid form. For this reason, it was found that most of the unreacted maleic anhydride leaked out of the system in a gasified state along with the wastewater from the water ring vacuum pump. In addition, a large amount of solidified maleic anhydride was found adhering to the gas suction part of the vacuum pump.

Comparative Example 2 Using the same raw materials and equipment as in Example 1, the temperature of the jacket part of the jacketed recovery trap was increased to 15%.
When the block SBR was denatured in the same manner as in Example 1 except that water adjusted to a temperature of but
The pressure worsened to 410mmHg gauge. Analysis of the obtained modified polymer pellet revealed that the block part was
1.3 parts by weight of maleic anhydride was grafted per 100 parts by weight of SBR, and 1.9 parts by weight of maleic anhydride remained as an unreacted substance, indicating that the modified polymer had a large amount of residual maleic anhydride.

Example 2 Styrene/ethylene butylene block copolymer obtained by hydrogenating a styrene/butadiene block copolymer with a styrene bond content of 30% by weight (hydrogenated block SBR) 100 parts by weight Maleic anhydride 3 parts by weight Stabilizer 0.1 part by weight Raw materials consisting of 0.3 parts by weight of di-t-butyl peroxide were mixed in a Henschel mixer, and 50
The modification reaction was carried out using an extruder with a mmφ biaxially rotating vent hole at a set temperature of 240° C. and a vent vacuum degree of 730 mmHg gauge pressure. The heat exchanger, recovery trap, and vacuum pump used were the same as in Example 1 under the same conditions, and dichlorobenzene was charged inside the recovery trap. As a result of the analysis, 98% of the unreacted maleic anhydride was solubilized in dichlorobenzene and could be collected in the recovery trap in a liquid state, and the recovered material had no pungent odor even though it contained maleic anhydride. It was found that this method was favorable in terms of working environment.

Comparative Example 3 The same raw materials and equipment as in Example 2 were used, except that oil adjusted to 120°C was poured into the outer tube of the heat exchanger connected to the vent hole to prevent clogging of the vent pipe. When the hydrogenated block SBR was modified using the method, unreacted maleic anhydride was
Only 29% could be recovered in liquid form, and the gas suction part of the water ring vacuum pump became clogged, making it impossible to operate.

Example 3 Isotactic polypropylene resin
Raw materials consisting of 100 parts by weight of maleic anhydride, 0.5 parts by weight of stabilizer, and 0.01 parts by weight were mixed in a Henschel mixer and denatured using the same equipment as in Example 2 and under the conditions that glycerin was placed in the recovery trap. 96% of the unreacted maleic anhydride was solubilized in the glycerin in the recovery trap and recovered in a liquid state.

Example 4 Ethylene-butene 1 copolymer elastomer
Raw materials consisting of 100 parts by weight of styrene, 10 parts by weight of stabilizer, 0.1 parts by weight of di-t-butyl peroxide and 0.7 parts by weight were heated and mixed in a Henschel mixer, and brought to the set temperature using a 50 mmφ co-rotating co-rotating extruder with vent holes. The modification reaction was carried out at 200° C. and a vent vacuum of 740 mmHg gauge pressure. The heat exchanger directly connected to the extruder vent hole was a double-tube heat exchanger having a structure in which the inlet of the heat exchanger section and the outlet of the heat exchanger section descended, and cooling water adjusted to 3° C. was flowed through the outer tube. Cooling water adjusted to 3°C was also flowed through the jacket of the recovery trap, oil for a vacuum pump was filled inside the recovery trap, and an oil rotary vacuum pump was used as the vacuum pump. Analysis after the modification reaction revealed that 97% of the unreacted styrene monomer was recovered in the recovery trap.

Example 5 A raw material consisting of 100 parts by weight of high-density polyethylene (powder), 1.5 parts by weight of acrylic acid, 0.01 parts by weight of stabilizer, 0.08 parts by weight of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, was Mix in a mixer, 30
mmφ biaxial extruder with counter-rotating vent holes.
The modification reaction was carried out at a set temperature of 190°C and a vent vacuum of 750 mmHg gauge pressure. The heat exchanger directly connected to the extruder vent hole is a double-tube heat exchanger with a structure in which the inlet of the heat exchanger section and the outlet of the heat exchanger section are descending.
Water adjusted to ℃ was run. Furthermore, a recovery trap with a jacket was connected to the outlet of this heat exchanger, and water adjusted to 20°C was also flowed through the jacket. The inside of the recovery trap was filled with naphthenic oil. A water ring vacuum pump was used as the vacuum pump. Analysis after the denaturation reaction revealed that unreacted acrylic acid
98% of the oil was recovered in liquid form in the naphthenic oil in the recovery trap.

Claims (1)

[Scope of Claims] 1 Thermoplastic resin and/or thermoplastic elastomer is treated with a styrene compound, a methacrylic acid ester compound, a cyanated olefin compound, an acrylic acid ester, or a fatty acid in the presence or absence of an organic peroxide. Vinyl ester, hydroxyalkyl group-containing (meth)acrylic ester, N-
Heat-melted with at least one olefinic unsaturated compound selected from alkylol (meth)acrylamide, ethylenically unsaturated carboxylic acid, aminoalkyl (meth)acrylamide, epoxyalkyl ester of ethylenically unsaturated carboxylic acid, and carboxylic acid anhydride. In a method for producing a modified polymer that is reacted in a kneader, when the unreacted olefinic unsaturated compound is removed from the molten mixture by venting under reduced pressure and recovered, (1) the vented unreacted olefinic unsaturated compound is recovered; The saturated compound is liquefied by heat exchange with a liquid heat exchange medium adjusted to a temperature that liquefies it, and the liquefied liquid flows continuously from the heat exchange section inlet to the heat exchange section outlet so that the liquefied liquid flows into the recovery trap by its own weight. A heat exchanger (2) having a structure in which the liquid olefinically unsaturated compound exiting the heat exchanger is collected in a liquid state, and a recovery trap is connected to the vent hole of the heating melt kneader, A method for producing a modified polymer, characterized in that the olefinically unsaturated compound is efficiently recovered in a liquid state.