JP2018044106A - Method for manufacturing polymer from which volatile component is removed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a purified polymer by removing a volatile component from the polymer stably without needs for large scale facility.SOLUTION: There is provided a method for manufacturing a purified polymer including a process for introducing a liquid article of a polymer containing a volatile component into a manufacturing container, a process for supplying over-heated moisture at 110°C or more into the manufacturing container, and a process for contacting the over-heated moisture with the liquid article and removing the volatile component under a condition that total pressure of the manufacturing container is in a pressure range of 700 to 800 torr.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a polymer from which volatile components have been removed.

  A display used for a thin-screen TV, a smartphone, a tablet terminal, or the like is a laminate of various materials, and an adhesive containing a polymer typified by a (meth) acrylic polymer is used for bonding. If the polymer used for the adhesive (for example, (meth) acrylic polymer) contains volatile components (for example, residual solvent, residual monomer, and other residual volatile components), the bleed out derived from these components If this occurs, the adhesive force may be further reduced. Therefore, it is desired that the volatile component contained in the polymer is extremely low.

  As a method for removing residual volatile components from an acrylic polymer, a method of adding water vapor as a devolatilization aid under a reduced pressure using a stirring vessel has been proposed (for example, see Patent Document 1). However, this method requires large-scale equipment such as a vacuum pump for reducing the pressure in the stirring vessel. Moreover, since the exhaust gas flow velocity becomes large by reducing the pressure, there is a problem that it is difficult to perform a stable continuous operation because the entrainment of the polymer is likely to block the piping and the condenser.

Japanese Patent No. 3722858

  An object of this invention is to provide the method of manufacturing the refined polymer by removing a volatile component from a polymer stably, without requiring a large-scale installation.

According to the invention, the object is
[1] A step of preparing a polymer liquid containing a volatile component in a production container,
A step of supplying superheated steam at 110 ° C. or higher into the production vessel, and a step of bringing the superheated steam into contact with the liquid material and removing volatile components under conditions where the total pressure of the production vessel is in the pressure range of 700 to 800 torr. A process for producing a purified polymer comprising:
[2] The method for producing a purified polymer according to [1], wherein the volatile component is at least one selected from a residual solvent, a residual monomer, a residual component of a polymerization initiator system, and a decomposition product thereof;
[3] A method for producing a purified polymer according to [1] or [2], wherein the boiling point of the volatile component exceeds 250 ° C .;
[4] A method for producing a purified polymer according to any one of [1] to [3], wherein the volatile component is 2,6-di-t-butyl-4-methylphenol;
[5] A method for producing a purified polymer according to any one of [1] to [4], wherein the temperature of the liquid when supplying superheated steam is 110 ° C. or higher;
[6] A method for producing a purified polymer according to any one of [1] to [5], wherein superheated steam is supplied in an amount of 20 to 3000 parts by mass with respect to 100 parts by mass of the liquid.
[7] A method for producing a purified polymer according to any one of [1] to [6], wherein the polymer is a (meth) acrylic block copolymer;
Is achieved by providing

  According to the present invention, a purified polymer can be produced by stably removing volatile components contained in a polymer without using a large facility.

Hereinafter, the present invention will be described in detail.
In the present specification, “(meth) acryl” means a generic name of “methacryl” and “acryl”, and “(meth) acryloyl” described later means a generic name of “methacryloyl” and “acryloyl”. The “(meth) acrylate” described later means a generic name of “methacrylate” and “acrylate”.

In the method for producing a purified polymer of the present invention, a process production vessel is prepared in which a liquid polymer containing a volatile component is first prepared in a production vessel.
The polymer used as the raw material of the present invention is not particularly limited, but the polymer of the present invention is usually a solid or semi-solid polymer at room temperature. It is difficult for such a polymer to remove volatile components without melting or dissolving-reprecipitation treatment. Although there is no restriction | limiting in particular about the kind of polymer, For example, (meth) acrylic-type polymer; Conjugated diene-type polymers, such as an isoprene-type polymer and a butadiene-type polymer, and its hydrogenated product; Styrene-type polymer block A block copolymer comprising a butadiene polymer block, a block copolymer comprising a styrene polymer block and an isoprene polymer block, and a block copolymer comprising a styrene polymer block and an isoprene / butadiene copolymer block. Examples thereof include a block copolymer containing an aromatic vinyl polymer block and a conjugated diene polymer block, such as a polymer, and a hydrogenated product thereof. Among them, the (meth) acrylic polymer whose transparency is one of its characteristics has a risk that the inherent properties such as transparency are impaired when the volatile component is removed by simple heating. Therefore, as a polymer used as a raw material, a (meth) acrylic polymer is an example of a suitable polymer. The (meth) acrylic polymer is a polymer mainly containing (typically 50 to 100% by mass) (meth) acrylic acid alkyl ester units. As the acrylic polymer, acrylic homopolymer, acrylic System random copolymer, (meth) acrylic block copolymer, and the like.

  The acrylic homopolymer is a homopolymer composed of one (meth) acrylic acid alkyl ester unit, and can be synthesized by homopolymerizing a (meth) acrylic acid alkyl ester.

  Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, ( Examples include (meth) acrylic acid alkyl esters having a C 1-20 alkyl group such as (meth) acrylic acid nonyl. Among these (meth) acrylic acid alkyl esters, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, (meth ) A (meth) acrylic acid alkyl ester having a C1-C9 alkyl group such as nonyl acrylate is preferred.

  As said acrylic random copolymer, the copolymer which combined 2 or more types of the said (meth) acrylic-acid alkylester is mentioned, For example, acrylic acid alkylesters, methacrylic acid alkylesters, acrylic acid alkylester, and methacrylic acid are mentioned. Combinations of acid alkyl esters and the like can be mentioned. Moreover, other monomer units other than the (meth) acrylic acid alkyl ester may be included. Examples of the other monomer units include vinyl aromatic monomers such as styrene; carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, and itaconic acid; acrylamide and vinyl acetate.

  The acrylic random copolymer that is one of the acrylic polymers preferably contains an alkyl acrylate unit as a main component. Here, containing as the main component means that the acrylic random copolymer contains the most alkyl acrylate units, and the acrylic alkyl ester unit content in the acrylic random copolymer is: Preferably it is 50-100 mass%, More preferably, it is 70-100 mass%, More preferably, it is 90-100 mass%.

  The weight average molecular weight (Mw) of the acrylic homopolymer and acrylic random copolymer is preferably 30,000 or more and 1,500,000 or less, more preferably 50,000 or more and 1,000,000 or less, Preferably they are 100,000 or more and 500,000 or less, Most preferably, they are 150,000 or more and 350,000 or less. When Mw is less than 30,000, the cohesive force of the hot melt adhesive is insufficient, and the performance required as an adhesive may not be exhibited.

  The above acrylic homopolymer and acrylic random copolymer may be used singly or in combination of two or more. Moreover, there is no restriction | limiting in particular in the manufacturing method of the said acrylic homopolymer and an acrylic random copolymer, According to the intended purpose, various polymers can be used. For example, the acrylic homopolymer and the acrylic random copolymer may be a polymer synthesized by an ordinary radical polymerization method or a polymer synthesized by a living radical polymerization method. Moreover, you may use the commercially available adhesive agent containing the said acrylic homopolymer or an acrylic random copolymer as it is.

  Among the above (meth) acrylic polymers, in the method for producing a purified polymer of the present invention, a (meth) acrylic block copolymer is used because a purified polymer can be produced without impairing the performance of the polymer. Preferably, a (meth) acrylic block copolymer (A) having at least one polymer block (a1) composed of an alkyl methacrylate unit and at least one polymer block (a2) composed of an alkyl acrylate unit. Is particularly preferred.

  Examples of the alkyl methacrylate that is a constituent unit of the polymer block (a1) include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, and n-hexyl methacrylate. Cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, isobornyl methacrylate, and the like. Among these, methyl methacrylate, ethyl methacrylate, and propyl methacrylate are preferable, and methyl methacrylate is preferred because it is economically easily available and the resulting polymer block (a1) has excellent durability and weather resistance. More preferred.

  The methacrylic acid alkyl ester unit, which is the constituent unit of the polymer block (a1), may be composed of one kind alone or may be composed of two or more kinds. The proportion of the alkyl methacrylate unit contained in the polymer block (a1) is preferably 60% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more in the polymer block (a1). The polymer block (a1) may be 100% by mass of methacrylic acid alkyl ester units.

  The polymer block (a1) may contain other monomer units as long as the effects of the present invention are not impaired. Examples of such other monomers include methacrylic acid esters having no functional groups other than methacrylic acid alkyl esters such as phenyl methacrylate and benzyl methacrylate; alkoxy methacrylates such as methoxyethyl methacrylate and ethoxyethyl methacrylate. 1,1-dimethylpropane-1 having a functional group such as alkyl ester, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2-aminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate; , 3-diol dimethacrylate, 1,1-dimethylbutane-1,4-diol dimethacrylate, 1,1-dimethylpentane-1,5-diol dimethacrylate, 1,1-dimethylhexane-1,6-dioe Dimethacrylate, 1,1-diethylpropane-1,3-diol dimethacrylate, 1,1-diethylbutane-1,4-diol dimethacrylate, 1,1-diethylpentane-1,5-diol dimethacrylate, 1, Bifunctional methacrylates such as 1-diethylhexane-1,6-diol dimethacrylate; alkyl acrylates described later; functional groups other than alkyl acrylates such as phenyl acrylate and benzyl acrylate Not acrylic acid ester; methoxyethyl acrylate, alkoxyalkyl acrylate such as ethoxyethyl acrylate, diethylaminoethyl acrylate, 2-hydroxyethyl acrylate, 2-aminoethyl acrylate, glycidyl acrylate, tetrahydride acrylate Acrylic acid ester having a functional group such as furfuryl; vinyl monomer having a carboxyl group such as (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, fumaric acid, (meth) acrylamide; Vinyl monomers having a functional group such as acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride; aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene; butadiene Conjugated diene monomers such as isoprene; olefin monomers such as ethylene, propylene, isobutene and octene; and lactone monomers such as ε-caprolactone and valerolactone. When these monomers are used, they are usually used in a small amount, but are preferably 40% by mass or less, more preferably 20% by mass with respect to the total mass of the monomers used for forming the polymer block (a1). % Or less, more preferably 10% by mass or less.

  Moreover, a polymer block (a1) may contain both the above-mentioned methacrylic acid alkylester unit and a bifunctional methacrylic acid ester unit. In this case, as the bifunctional methacrylate ester, 1,1-dimethylpropane-1,3-diol dimethacrylate, 1,1-dimethylbutane-1,4-diol dimethacrylate, 1,1-dimethylpentane-1 , 5-diol dimethacrylate, 1,1-dimethylhexane-1,6-diol dimethacrylate, 1,1-diethylpropane-1,3-diol dimethacrylate, 1,1-diethylbutane-1,4-diol di Preferred are methacrylate, 1,1-diethylpentane-1,5-diol dimethacrylate, and 1,1-diethylhexane-1,6-diol dimethacrylate, 1,1-dimethylpropane-1,3-diol dimethacrylate, 1,1-dimethylbutane-1,4-diol dimethacrylate, 1,1 Dimethyl-1,5-diol dimethacrylate, and 1,1-dimethyl hexane-1,6-diol dimethacrylate are more preferred. The content of the bifunctional methacrylic acid ester unit relative to all the monomer units of the polymer block (a1) is preferably in the range of 0.5 to 80% by mass, more preferably in the range of 2 to 65% by mass, 45 The range of ˜60% by mass is more preferable. Further, the total content of the methacrylic acid alkyl ester unit and the bifunctional methacrylic acid ester unit with respect to all the monomer units of the polymer block (a1) is preferably in the range of 80 to 100% by mass, and 90 to 100% by mass. % Range is more preferable, the range of 95-100 mass% is further more preferable, and 100 mass% may be sufficient.

The glass transition temperature of the polymer block (a1) is preferably 25 ° C. or higher, more preferably 50 ° C. or higher, and further preferably 60 ° C. or higher.
The (meth) acrylic block copolymer (A) may contain two or more polymer blocks (a1). In that case, the polymer blocks (a1) may be the same. May be different.

  The weight average molecular weight (Mw) of the polymer block (a1) is not particularly limited, but is preferably in the range of 1,000 to 50,000, and more preferably in the range of 1,000 to 25,000. More preferably, it is in the range of 4,000 to 25,000. In addition, in this specification, Mw means the weight average molecular weight of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

  Examples of the alkyl acrylate ester that is a structural unit of the polymer block (a2) include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, Examples include cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, lauryl acrylate, tridecyl acrylate, stearyl acrylate, and the like.

  When the alkyl group of the alkyl acrylate ester is a short chain alkyl group having 4 or less main chain carbon atoms (for example, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate) Etc.) tend to improve the fluidity of the (meth) acrylic block copolymer (A). When the alkyl group contained in the acrylic acid alkyl ester is a long chain alkyl group having 6 or more main chain carbon atoms (for example, acrylic acid alkyl ester includes n-hexyl acrylate, cyclohexyl acrylate, 2-acrylic acid 2- Ethylhexyl, n-octyl acrylate, lauryl acrylate, tridecyl acrylate, stearyl acrylate, etc.) tend to improve the low-temperature characteristics of the (meth) acrylic block copolymer (A).

  The acrylic acid alkyl ester unit, which is a constituent unit of the polymer block (a2), may be composed of one kind alone or may be composed of two or more kinds. The proportion of acrylic acid alkyl ester units contained in the polymer block (a2) is preferably 60% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more in the polymer block (a2). The polymer block (a2) may be 100% by mass of an acrylic acid alkyl ester unit.

  The polymer block (a2) may contain other monomer units as long as the effects of the present invention are not impaired. Examples of other monomers constituting such units include, for example, methacrylic acid alkyl esters and methacrylic acid alkyl esters other than methacrylic acid alkyl esters and methacrylic acid alkyl esters described in the polymer block (a1), functional groups. Other than methacrylic acid ester, bifunctional methacrylic acid ester, acrylic acid alkyl ester, acrylic acid ester having no functional group, acrylic acid ester having a functional group, vinyl monomer having a carboxyl group, functional group And vinyl monomers, aromatic vinyl monomers, conjugated diene monomers, olefin monomers, and lactone monomers. When these monomers are used, they are usually used in a small amount, but are preferably 40% by mass or less, more preferably 20% by mass with respect to the total mass of the monomers used for forming the polymer block (a1). % Or less, more preferably 10% by mass or less.

The glass transition temperature of the polymer block (a2) is preferably −20 ° C. or lower, and more preferably −30 ° C. or lower.
When the glass transition temperature of the polymer block (a2) is within the above range, a (meth) acrylic block copolymer excellent in properties such as flexibility can be obtained even in a low temperature region. Among the above acrylic esters, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, acrylic are preferable because the glass transition temperature of the polymer block (a2) is within the above preferred range and is easily available. The acid n-octyl is preferred.

  The (meth) acrylic block copolymer (A) may contain two or more polymer blocks (a2). In this case, the polymer blocks (a2) may be the same. May be different.

  Further, the difference in glass transition temperature between the polymer block (a1) and the polymer block (a2) in the (meth) acrylic block copolymer (A) is preferably 70 ° C. or higher, more preferably 100 ° C. or higher. .

The (meth) acrylic block copolymer (A) has the general formula: when the polymer block (a1) is “A”; and the polymer block (a2) is “B”;
(AB) n
(AB) n-A
B- (AB) n
(AB) nZ
(BA) n-Z
(Wherein n represents an integer of 1 to 30 and Z represents a coupling site (a coupling site after a coupling agent reacts with a polymer terminal to form a chemical bond)). Is preferred. The value of n is preferably 1 to 15, more preferably 1 to 8, and further preferably 1 to 4. Among the above structures, a linear block copolymer represented by (AB) n, (AB) n-A, or B- (AB) n is preferable, and is represented by AB. A diblock copolymer or a triblock copolymer represented by ABA is particularly preferable.

  In the (meth) acrylic block copolymer (A), the content of the polymer block (a1) is not particularly limited, but is preferably 2 to 55% by mass, and preferably 10 to 35% by mass. It is more preferable.

  The weight average molecular weight (Mw) of the (meth) acrylic block copolymer (A) is preferably 10,000 to 350,000, more preferably 20,000 to 200,000, 25 Is more preferably 30,000 to 170,000, still more preferably 30,000 to 150,000.

  In the (meth) acrylic block copolymer (A), the molecular weight distribution (Mw / Mn) is preferably 1.0 to 1.5, more preferably 1.0 to 1.4, More preferably, it is 1.0 to 1.3.

  The manufacturing method in particular of (meth) acrylic block copolymer (A) is not restrict | limited, It can manufacture by the manufacturing method according to a well-known method. In general, as a method for obtaining a block copolymer having a narrow molecular weight distribution, a method of living polymerizing monomers as constituent units is employed. Examples of such living polymerization methods include living polymerization using an organic rare earth metal complex as a polymerization initiator (see, for example, JP-A-6-93060), and alkali metal using an organic alkali metal compound as a polymerization initiator. Alternatively, a method of living anion polymerization in the presence of a mineral acid salt such as an alkaline earth metal salt (see, for example, JP-A-5-507737), an organic alkali metal compound as a polymerization initiator, and an organic aluminum compound. And a living anion polymerization method (see, for example, JP-A No. 11-335432 and International Publication No. 2013/141105), an atom transfer radical polymerization method (ATRP), and the like. Moreover, you may use a commercial item as a (meth) acrylic-type block copolymer (A). Examples of commercially available products include “Clarity (registered trademark) series” manufactured by Kuraray Co., Ltd.

  The polymer used as a raw material in the present invention contains a volatile component. In addition, the volatilization as used in the field of this invention means the component which can volatilize at 20 degreeC under atmospheric pressure. Examples of the volatile component include a residual monomer that is a raw material of the polymer, a residual solvent used in the polymerization reaction, a residual component of the polymerization initiator system, a decomposition product of the polymerization initiator system component generated by stopping the polymerization reaction, etc. Is mentioned.

  The boiling point of the volatile component is not particularly limited, but in the method for producing the purified polymer of the present invention, when the boiling point of the volatile component is high temperature, for example, when it exceeds 250 ° C., these volatile components are sufficiently reduced. It becomes possible to do.

  Specific examples of the volatile component include methyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 1,1-dimethylpropane-1,3-diol dimethacrylate, toluene, 1,1,4,7,10. , 10-hexamethyltriethylenetetramine, 2,6-di-t-butyl-4-methylphenol, and the like. In particular, when the volatile component is 2,6-di-t-butyl-4-methylphenol, it is difficult to remove because the polymer may be deteriorated only by normal heating. . In the present invention, such a volatile component that is difficult to remove can be sufficiently removed from the polymer under relatively short time and low temperature conditions to produce a purified polymer.

  The production container used for production of the purified polymer of the present invention is not particularly limited as long as it can remove volatile components from the polymer and the total pressure of the production container falls within a desired range. Examples of the production container include a container having a stirring blade, a twin-screw kneader, a twin-screw dryer, a single-screw extruder, and a twin-screw extruder. The production container may be provided with an inlet and an outlet for a polymer containing a volatile component, and an inlet and an outlet for superheated steam.

  In the present invention, a polymer liquid containing a volatile component is prepared in a production container. There is no particular limitation on the method for preparing the liquid polymer in the production container. For example, a polymer melt that is solid or semi-solid at room temperature may be produced outside the production container, and then introduced into the production container from an inlet provided in the production container, for example. In addition, a polymer containing a volatile component may be introduced into a production container as it is, for example, at room temperature, and the polymer may be heated in the production container as necessary to form a liquid. The heating temperature of the polymer can be appropriately set according to the melting temperature of the polymer as a raw material. The heating temperature of the polymer is usually 110 ° C. or higher, preferably 100 ° C. or higher and 275 ° C. or lower, more preferably 110 ° C. or higher and 220 ° C. or lower. When heated above the upper limit temperature, there is a risk that the polymer will deteriorate, and there is a risk that the original properties of the polymer will be impaired. When the temperature is lower than the lower limit temperature, the polymer may not be sufficiently heated, or moisture may be taken into the polymer as an impurity by contact with superheated steam.

  The atmosphere in the production container is not particularly limited. However, since the production container becomes relatively high in temperature, it is desirable that the atmosphere does not promote deterioration of the polymer. Among them, an inert gas such as nitrogen gas or argon gas is preferable, and nitrogen gas is preferable from the viewpoint of cost.

  The method for producing a purified polymer of the present invention includes a step of supplying superheated steam at 110 ° C. or higher into a production container in which a polymer liquid is prepared. When steam having a temperature of less than 110 ° C. is used, the effect of sufficiently removing volatile components, for example, volatile components having a boiling point exceeding 250 ° C., is insufficient, and condensation occurs when the steam comes into contact with the production vessel or polymer. In some cases, a separate dehydration step such as drying under reduced pressure may be required.

  The temperature of the superheated steam is preferably 110 ° C. or higher and 275 ° C. or lower, and more preferably 110 ° C. or higher and 220 ° C. or lower. When the temperature of superheated steam exceeds the upper limit, the polymer may be degraded due to decomposition or the like.

  The method for introducing superheated steam into the production vessel is not particularly limited. For example, water is sent to the heat exchanger by a pump, the superheated steam is produced by the heat exchanger, and the obtained superheated steam is introduced into the production vessel. This can be done. The amount of superheated steam introduced can be controlled by the pumping amount.

  The amount of superheated steam supplied to the production vessel can be appropriately set in consideration of the polymer, the size and form of the production vessel, etc., but usually 20 to 100 parts by mass of the polymer containing the volatile component as a raw material. 3000 parts by mass, preferably 50 to 2000 parts by mass, more preferably 100 to 1000 parts by mass. If the supply amount is less than or equal to the lower limit value, it may be difficult to efficiently remove volatile components. When the supply amount exceeds the above upper limit, the cost for purifying the polymer may increase excessively, or the amount of superheated steam contacting the polymer may be too large, and moisture may be taken into the polymer as an impurity.

  In the method for producing the purified polymer of the present invention, the superheated steam supplied in the production vessel is brought into contact with the polymer melt, and the volatile component is used under the condition that the total pressure in the production vessel is in the pressure range of 700 to 800 torr. The process of removing. By this contact, the superheated steam is once taken into the melt, and discharged to the outside of the polymer liquid along with the superheated steam in which the volatile component is taken in. In addition, by introducing superheated steam into the production container within this pressure range, it is possible to remove volatile components from the polymer without passing through special decompression conditions and pressurization conditions.

  Water vapor in contact with the polymer liquid must be in a superheated state. For example, when the water vapor in contact with the polymer liquid is saturated water vapor or the like, liquid water may be generated by the contact, and liquid water may be taken into the polymer. Therefore, it may be necessary to go through a dehydration process such as drying under reduced pressure. In addition, when liquid water has been generated, the liquid water is brought into contact with a sufficiently heated polymer, so that the water evaporates again. The corresponding amount of heat is taken away from the polymer. Therefore, the temperature of the polymer may be greatly reduced, and the volatile component may not be sufficiently reduced. Further, in order to cope with the temperature decrease of the polymer accompanying the evaporation of water, it is necessary to further heat the polymer, and the polymer may be locally exposed to a very high temperature. The physical properties inherent to the polymer may be impaired.

  In addition, in order to remove volatile components by using an inert gas such as nitrogen or an organic solvent vapor such as toluene instead of superheated steam, at least the same amount of gas and heating of the gas are required. It is disadvantageous in terms of cost compared to the case of using superheated steam. Further, when an organic solvent vapor is used, it may be likely to remain depending on the properties of the polymer, and there is a possibility that the environment may be adversely affected.

  There is no particular limitation on the method for contacting the polymer liquid with superheated steam. For example, superheated steam may be brought into the liquid by bringing the superheated steam into contact with the top surface of the liquid under stirring. Also, in order to more efficiently perform contact between the polymer liquid and superheated steam, an introduction path for superheated steam is provided in the production container, and an end of this introduction path is inserted into the liquid, Superheated steam may be discharged from the end of the introduction path so that the liquid material and superheated steam are brought into direct contact with each other.

  The contact time between the liquid polymer and the superheated steam can be appropriately set according to the type and amount of the volatile component contained in the polymer. The contact time between the polymer liquid and the superheated steam is preferably 1 minute to 20 hours, and more preferably 3 minutes to 10 hours.

  The gas containing superheated steam in contact with the liquid polymer is discharged from the production vessel. There is no particular limitation on the method of discharging from the production container, but it is desirable that the superheated steam be discharged under conditions that do not aggregate in the production container. For example, superheated steam discharged from the production container is placed in a water tank provided outside the production container and controlled to a sufficiently low temperature (for example, 10 to 30 ° C.) or a condenser through which cooling water is passed. A gas discharge path for introducing a gas to be contained is provided, and the gas containing superheated steam in contact with the liquid material can be discharged from the production container through the gas discharge path.

  It is desirable to have a step of removing the superheated steam contained in the liquid polymer after contacting with the superheated steam. The method for removing the superheated steam contained in the liquid material is not particularly limited.For example, after contacting the superheated steam, the inside of the production vessel is stirred at normal pressure or reduced pressure while maintaining the temperature of the polymer. The superheated steam contained in the polymer liquid can be removed.

The obtained purified polymer liquid may be taken out from the production container as a liquid in a heated state, or may be taken out from the production container after being cooled in the production container.
The purified polymer thus obtained has a sufficiently reduced amount of volatile components. For example, the ratio of the volatile component having a boiling point exceeding 250 ° C. contained in the purified polymer is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and still more preferably 0.00% by mass in the purified polymer. It can be reduced to 01% by mass or less. The amount of water contained in the purified polymer is preferably 1% by mass or less, more preferably 0.5% by mass or less in the purified polymer.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to this Example.
The (meth) acrylic block copolymer used in the examples described later was polymerized according to the following synthesis example. In the synthesis examples, the raw materials were dried and purified by a conventional method, deaerated with nitrogen, and transferred and supplied under a nitrogen atmosphere.

[Monomer consumption rate]
In the following synthesis examples, the consumption rate of each monomer after polymerization was determined by collecting 0.5 mL of the reaction solution, mixing it in 0.5 mL of methanol, mixing 0.1 mL from the mixture, ¹ H-NMR measurement was carried out under the following measurement conditions after dissolving in 0.5 mL of chloroform, and a peak derived from a proton directly connected to a carbon-carbon double bond of (meth) acrylic acid ester used as a monomer ( (Chemical shift value 5.79-6.37 ppm) and calculated from the change in the ratio of the integral value of the peak (chemical shift value 7.00-7.38 ppm) derived from the proton directly linked to the aromatic ring of toluene used as the solvent. .

⁽¹ H-NMR measurement conditions)
Apparatus: Nuclear magnetic resonance apparatus "JNM-ECX400" manufactured by JEOL Ltd.
Temperature: 25 ° C

[Number average molecular weight (Mn), weight average molecular weight (Mw), molecular weight distribution (Mw / Mn)]
The number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) of the (meth) acrylic block copolymer are measured under the following measurement conditions by GPC (gel permeation chromatography). The number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) in terms of standard polystyrene were calculated.

(GPC measurement conditions)
Equipment: GPC equipment “HLC-8220GPC” manufactured by Tosoh Corporation
Separation column: “TSKgel SuperMultipore HZ-M (column diameter = 4.6 mm, column length = 15 cm)” manufactured by Tosoh Corporation (used by connecting two in series)
Eluent: Tetrahydrofuran Eluent flow rate: 0.35 mL / min Column temperature: 40 ° C
Detection method: differential refractive index (RI)

[BHT content]
The BHT content in the (meth) acrylic block copolymer was measured by accurately weighing (meth) acrylic block copolymer and tetradecane or tridecane as an internal standard, and dissolving in tetrahydrofuran or chloroform. Using Shimadzu Corporation GC-2010Plus or GC-2014), the peak area ratio of BHT and internal standard was calculated, and a calibration curve (peak area ratio (BHT / internal standard) on the horizontal axis, vertical axis) The weight ratio (BHT / internal standard) was plotted in Fig. 5 and the calculation formula was calculated) to calculate the BHT weight.

[Moisture percentage]
The water content of the (meth) acrylic block copolymer was evaluated by dissolving the (meth) acrylic block copolymer in tetrahydrofuran and using a Karl Fischer moisture measuring device (KF-200 manufactured by Mitsubishi Chemical Analytic Co., Ltd.). Then, the moisture content of the solution and the solvent was calculated.

[UV curing rate]
The UV curing rate of the (meth) acrylic block copolymer was evaluated by mixing 0.01 part by weight of an initiator (Irgacure 184) with the (meth) acrylic block copolymer, and measuring the viscosity / viscoelasticity ( Eihiro Seiki Co., Ltd. HAAKE MARS III), measuring jig: P20 CS L ER (φ = 20 mm parallel plate), film thickness: 0.15 mm, measuring temperature: 25 ° C., measuring frequency: 5 Hz, UV irradiation intensity The storage elastic modulus (Pa) G ′ is measured under the condition of 150 mW / cm ² , the storage elastic modulus at the start of UV irradiation is G ′ _min , the storage elastic modulus at the end of UV irradiation is G ′ _max , and the UV irradiation amount UV irradiation such that (G ′ _S −G ′ _min ) / (G ′ _max −G ′ _min ) × 100 = 90 (%), where G ′ _S is the storage elastic modulus at time (seconds) The calculation was performed by calculating the quantity time T (G ′ 90%).

[Heat resistance test]
In the heat resistance test, the test piece obtained in the following [Test piece preparation] section was allowed to stand in an environment of 95 ° C., and the YI value of the test piece after the lapse of 500 hours was measured with a color meter (SD5000 manufactured by Nippon Denshoku Industries Co., Ltd.). ). At this time, the standard was the glass plate used for the test piece preparation.

[Light resistance test]
In the light resistance test, a test piece obtained in the following [Test piece preparation] section was used with a xenon weather meter (Atlas Weatherometer Ci4000, manufactured by Toyo Seiki Seisakusho Co., Ltd.). Illuminance (340 nm): 0.35 W / m ² Panel temperature: 63 ° C., chamber temperature: 40 ° C., humidity: 10%, and the YI value of the test piece after 500 hours passed is measured with a color meter (SD5000 manufactured by Nippon Denshoku Industries Co., Ltd.). It was carried out by measuring. At this time, the standard was the glass plate used for the test piece preparation.

[Test specimen preparation]
A (meth) acrylic block copolymer is mixed with 0.01 parts by weight of an initiator (Irgacure 184), sandwiched between two glass plates with a clearance of 100 μm, and integrated with a metal halide lamp. A test piece was prepared by irradiating with ultraviolet rays to be cured so that the irradiation amount was 1000 mJ / cm ² .

[Synthesis Example 1]
(Process (1))
After 1.36 kg of toluene was added to a 3 L flask that had been dried and purged with nitrogen, 1.58 g of 1,1,4,7,10,10-hexamethyltriethylenetetramine as a Lewis base was added while stirring. 6.87 mmol), and 21.4 g (10.8 mmol) of a toluene solution containing 26.4% by mass of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as an organoaluminum compound were sequentially added. And cooled to -20 ° C. To this was added 4.24 g (6.55 mmol) of a cyclohexane solution containing 9.90% by mass of sec-butyllithium as an organolithium compound, and then 2.62 g (26.2 mmol) of methyl methacrylate was added as a monomer. Anion polymerization was started. After sampling the reaction solution 15 minutes after the completion of the addition of methyl methacrylate and confirming that the consumption rate of methyl methacrylate is 100%, 1,1-dimethylpropane-1,3-diol dimethacrylate 7.75 g of a mixture of 23 g (17.6 mmol) and methyl methacrylate 3.52 g (35.2 mmol) was added all at once. After 150 minutes from the end of the addition of the mixture, the reaction solution changed from the original yellow color to colorless. After stirring for another 20 minutes, the reaction solution was sampled.

  The consumption rate of 1,1-dimethylpropane-1,3-diol dimethacrylate and methyl methacrylate in step (1) was 100%. Moreover, Mn of the obtained polymer was 1,700 and Mw / Mn was 1.14.

(Process (2))
Subsequently, while stirring the reaction solution at −20 ° C., 15.6 g (7%) of a toluene solution containing 26.4% by mass of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as an organoaluminum compound was obtained. Then, 426 g (2.31 mol) of 2-ethylhexyl acrylate was added as a monomer at a rate of 7 g / min. The reaction solution was sampled immediately after completion of the monomer addition.
The consumption rate of 2-ethylhexyl acrylate in the step (2) was 100%. Moreover, Mn of the obtained polymer was 85,900 and Mw / Mn was 1.15.

(Process (3))
Subsequently, while stirring the reaction solution at −20 ° C., 3.86 g (16.1 mmol) of 1,1-dimethylpropane-1,3-diol dimethacrylate and 3.22 g (3.22 mmol) of methyl methacrylate as monomers. 7.08 g of the mixture was added all at once and then the temperature was raised to 20 ° C. at a rate of 2 ° C./min. The reaction solution was sampled 60 minutes after the addition of the above mixture.
The consumption rate of 1,1-dimethylpropane-1,3-diol dimethacrylate and methyl methacrylate in step (3) was 100%.

(Process (4))
Subsequently, while stirring the reaction solution at 20 ° C., 37.8 g of 50% by mass aqueous acetic acid was added to stop the anionic polymerization, and the methacrylic polymer block (A)-(meth) acrylic polymer block (B). -The solution containing the (meth) acrylic-type block copolymer which is a triblock copolymer couple | bonded in order of the methacrylic-type polymer block (A) (ABA) was obtained. The Mn of the (meth) acrylic block polymer sampled from such a solution was 87,900, and Mw / Mn was 1.08.

(Process (5))
Next, the resulting solution was heated for 90 minutes while stirring at 90 ° C. under a nitrogen flow to form a catalyst metal acetate. The solution was cooled to 25 ° C., and then centrifuged for 30 minutes at a centrifugal force of 18,800 G using a centrifuge (manufactured by Hitachi Koki Co., Ltd., himacCR22GII) to precipitate acetate, and the supernatant was collected. . After removing the solvent from the collected supernatant liquid at 60 ° C. using an evaporator, the solution was further dried at 100 ° C. and 30 Pa to obtain 440 g of a (meth) acrylic block copolymer (hereinafter referred to as “(meth) acrylic block copolymer). Polymer (1) ") was obtained. The BHT content of the (meth) acrylic block copolymer (1) was 1.5 wt%.

[Synthesis Example 2]
(Process (1))
After 1.47 kg of toluene was added to a 3 L flask which had been dried and purged with nitrogen, 1.75 g of 1,1,4,7,10,10-hexamethyltriethylenetetramine as a Lewis base was added while stirring. 7.59 mmol), and 23.6 g (11.9 mmol) of a toluene solution containing 26.4% by mass of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as an organoaluminum compound. And cooled to -20 ° C. To this was added 4.93 g (7.23 mmol) of a cyclohexane solution containing 9.40% by mass of sec-butyllithium as an organolithium compound, and then 2.90 g (29.0 mmol) of methyl methacrylate was added as a monomer. Anion polymerization was started. After sampling the reaction solution 15 minutes after the completion of the addition of methyl methacrylate and confirming that the consumption rate of methyl methacrylate is 100%, 1,1-dimethylpropane-1,3-diol dimethacrylate 9.02 g of a mixture of 92 g (20.5 mmol) and methyl methacrylate 4.10 g (41.0 mmol) was added all at once. After 150 minutes from the end of the addition of the mixture, the reaction solution changed from the original yellow color to colorless. After stirring for another 20 minutes, the reaction solution was sampled.

  The consumption rate of 1,1-dimethylpropane-1,3-diol dimethacrylate and methyl methacrylate in step (1) was 100%. Moreover, Mn of the obtained polymer was 1,800 and Mw / Mn was 1.14.

(Process (2))
Subsequently, while stirring the reaction solution at −20 ° C., 17.2 g (8%) of a toluene solution containing 26.4% by mass of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as an organoaluminum compound was obtained. Then, 196 minutes later, 496 g of a mixture of 248 g (1.35 mol) of 2-ethylhexyl acrylate and 248 g (1.91 mol) of 2-methoxyethyl acrylate was added at a rate of 8 g / min. The reaction solution was sampled immediately after completion of the monomer addition.

  The consumption rate of 2-ethylhexyl acrylate and 2-methoxyethyl acrylate in step (2) was 100%. Moreover, Mn of the obtained polymer was 88,000 and Mw / Mn was 1.13.

(Process (3))
Then, while stirring the reaction solution at −20 ° C., 4.52 g (18.8 mmol) of 1,1-dimethylpropane-1,3-diol dimethacrylate and 3.76 g (37.6 mmol) of methyl methacrylate were used as monomers. After adding 8.28 g of the mixture in a lump, the temperature was raised to 20 ° C. at a rate of 2 ° C./min. The reaction solution was sampled 150 minutes after the addition of the above mixture.
The consumption rate of 1,1-dimethylpropane-1,3-diol dimethacrylate and methyl methacrylate in step (3) was 100%.

(Process (4))
Subsequently, while stirring the reaction solution at 20 ° C., 41.8 g of 50% by mass aqueous acetic acid was added to stop the anionic polymerization, and the methacrylic polymer block (A)-(meth) acrylic polymer block (B). -The solution containing the (meth) acrylic-type block copolymer which is a triblock copolymer couple | bonded in order of the methacrylic-type polymer block (A) (ABA) was obtained. The Mn of the (meth) acrylic block polymer sampled from such a solution was 94,800 and Mw / Mn was 1.10.

(Process (5))
Next, the resulting solution was heated for 90 minutes while stirring at 90 ° C. under a nitrogen flow to form a catalyst metal acetate. The solution was cooled to 25 ° C., and then centrifuged for 30 minutes at a centrifugal force of 18,800 G using a centrifuge (manufactured by Hitachi Koki Co., Ltd., himacCR22GII) to precipitate the acetate, and the supernatant was collected. . After removing the solvent from the collected supernatant using an evaporator at 60 ° C., the solvent was further dried at 100 ° C. and 30 Pa to obtain 510 g of a (meth) acrylic block copolymer (hereinafter referred to as “(meth) acrylic block copolymer). Polymer (2) ") was obtained. The BHT content of the (meth) acrylic block copolymer (2) was 1.7 wt%.

[Synthesis Example 3]
After replacing the interior of the 2 L three-necked flask with nitrogen, 870 g of toluene and 44.0 g of 1,2-dimethoxyethane were added at room temperature, followed by isobutylbis (2,6-di-t-butyl-4-methylphenoxy). 30.9 g of a toluene solution containing 20.7 mmol of aluminum was added, and further 2.99 g of a mixed solution of cyclohexane and n-hexane containing 5.17 mmol of sec-butyllithium was added. Next, 21.7 g of methyl methacrylate was added thereto. The reaction mixture was initially colored yellow, but became colorless after 60 minutes of stirring at room temperature. At this time, the polymerization conversion rate of methyl methacrylate was 99.9% or more. Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., and 288.4 g of n-butyl acrylate was added dropwise over 2 hours. After completion of the addition, the mixture was stirred at −30 ° C. for 5 minutes, and then 3.5 g of methanol was added. The polymerization reaction was stopped by adding. At this time, the polymerization conversion rate of n-butyl acrylate was 99.9% or more. The obtained reaction solution was poured into 15 kg of methanol to precipitate an oily precipitate. The oily precipitate was collected and dried to obtain 310.0 g of a diblock copolymer (hereinafter referred to as “(meth) acrylic block copolymer (3)”). Mn of the (meth) acrylic block copolymer (3) was 51,000, Mw / Mn was 1.33, and the BHT content was 1.5 wt%.

[Synthesis Example 4]
(Process (1))
After adding 1.39 kg of toluene to a 3 L flask that had been dried and purged with nitrogen, 1.53 g of 1,1,4,7,10,10-hexamethyltriethylenetetramine as a Lewis base was added while stirring. 6.62 mmol), and 20.6 g (10.4 mmol) of a toluene solution containing 26.4% by mass of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as an organoaluminum compound were sequentially added. And cooled to -20 ° C. To this was added 4.08 g (6.31 mmol) of a cyclohexane solution containing 9.90% by mass of sec-butyllithium as an organolithium compound, and then 2.53 g (25.2 mmol) of methyl methacrylate was added as a monomer. Anion polymerization was started. After sampling the reaction solution 15 minutes after the completion of the addition of methyl methacrylate and confirming that the consumption rate of methyl methacrylate is 100%, 1,1-dimethylpropane-1,3-diol dimethacrylate 27.23 g of a mixture of 33 g (18.0 mmol) and methyl methacrylate 22.9 g (22.9 mmol) was added in one batch. 260 minutes after completion of the addition of the mixture, the reaction solution changed from the original yellow color to colorless. After stirring for another 20 minutes, the reaction solution was sampled.

  The consumption rate of 1,1-dimethylpropane-1,3-diol dimethacrylate and methyl methacrylate in step (1) was 100%. Moreover, Mn of the obtained polymer was 4,800 and Mw / Mn was 1.10.

(Process (2))
Subsequently, while stirring the reaction solution at −20 ° C., 8.74 g (4 of toluene solution containing 26.4% by mass of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as an organoaluminum compound was obtained. .41 mmol), and 1 minute later, 430 g (2.34 mol) of 2-ethylhexyl acrylate was added as a monomer at a rate of 7 g / min. The reaction solution was sampled immediately after completion of the monomer addition.
The consumption rate of 2-ethylhexyl acrylate in the step (2) was 100%. Moreover, Mn of the obtained polymer was 76,000 and Mw / Mn was 1.10.

(Process (3))
Subsequently, while stirring the reaction solution at −20 ° C., 3.92 g (16.3 mmol) of 1,1-dimethylpropane-1,3-diol dimethacrylate and 20.7 g (20.7 mmol) of methyl methacrylate were used as monomers. 24.62 g of the mixture was added at once, and then the temperature was raised to 20 ° C. at a rate of 2 ° C./min. The reaction solution was sampled 90 minutes after the addition of the mixture.
The consumption rate of 1,1-dimethylpropane-1,3-diol dimethacrylate and methyl methacrylate in step (3) was 100%.

(Process (4))
Subsequently, while stirring the reaction solution at 20 ° C., 32.5 g of 50% by mass aqueous acetic acid was added to stop the anionic polymerization, and the methacrylic polymer block (A)-(meth) acrylic polymer block (B). -The solution containing the (meth) acrylic-type block copolymer which is a triblock copolymer couple | bonded in order of the methacrylic-type polymer block (A) (ABA) was obtained. The (meth) acrylic block polymer sampled from this solution had Mn of 81,700 and Mw / Mn of 1.19.

(Process (5))
Next, the resulting solution was heated for 90 minutes while stirring at 90 ° C. under a nitrogen flow to form a catalyst metal acetate. The solution was cooled to 25 ° C., and then centrifuged for 30 minutes at a centrifugal force of 18,800 G using a centrifuge (manufactured by Hitachi Koki Co., Ltd., himacCR22GII) to precipitate acetate, and the supernatant was collected. . The recovered supernatant is dropped into 5 times the amount of methanol, re-precipitated, and further dried at 80 ° C. and 30 Pa, followed by 480 g of a (meth) acrylic block copolymer (hereinafter referred to as “(meth) acrylic block copolymer”). Polymer (4) ") was obtained. The BHT content of the (meth) acrylic block copolymer (4) was 2.2 wt%.
Examples and comparative examples are described below.

[Example 1]
260 g of (meth) acrylic block copolymer (1) was charged into an autoclave (glass reactor TEM-U1000N type capacity: about 1 L manufactured by Heat Resistant Glass Industry Co., Ltd.). When this was heated to 160 ° C. with an autoclave heater, 160 ° C. superheated steam was directly added to the copolymer from the introduction tube inserted from the top of the autoclave, and the stirring blade was rotated at 400 rpm and stirred. Superheated steam was obtained by first sending pure water to a heat exchanger with a liquid feed pump and heating it. The introduction rate of superheated steam was controlled by a liquid feed pump and adjusted to 510 g / h. The gas discharged from the autoclave was condensed by blowing directly into 3 L of pure water cooled to 20 ° C. in a jacketed water tank. Superheated steam was introduced for 90 minutes, that is, 2.9 parts by weight of superheated steam was introduced with respect to the (meth) acrylic block copolymer (1). About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

[Example 2]
250 g of (meth) acrylic block copolymer (2) was charged into an autoclave (glass reactor TEM-U1000N type capacity: about 1 L manufactured by Heat Resistant Glass Industry Co., Ltd.). When this was heated to 160 ° C. with an autoclave heater, 160 ° C. superheated steam was directly added to the copolymer from the introduction tube inserted from the top of the autoclave, and the stirring blade was rotated at 400 rpm and stirred. Superheated steam was obtained by first sending pure water to a heat exchanger with a liquid feed pump and heating it. The introduction rate of superheated steam was controlled by a liquid feed pump and adjusted to 500 g / h. The gas discharged from the autoclave was condensed by blowing directly into 3 L of pure water cooled to 20 ° C. in a jacketed water tank. Superheated steam was introduced for 90 minutes, that is, 3 parts by weight of superheated steam was introduced with respect to the (meth) acrylic block copolymer (2). About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

[Example 3]
250 g of (meth) acrylic block copolymer (3) was charged into an autoclave (metal reactor TEM-D type capacity 1 L manufactured by Heat Resistant Glass Industry Co., Ltd.). When this was heated up to 200 ° C. with an autoclave heater, 200 ° C. superheated steam was directly added to the copolymer from the introduction tube inserted from the top of the autoclave, and the stirring blade was rotated at 400 rpm and stirred. Superheated steam was obtained by first sending pure water to a heat exchanger with a liquid feed pump and heating it. The introduction rate of superheated steam was controlled by a liquid feed pump and adjusted to 500 g / h. The gas discharged from the autoclave was condensed by blowing directly into 3 L of pure water cooled to 20 ° C. in a jacketed water tank. Superheated steam was introduced for 40 minutes, that is, 1.3 parts by weight of superheated steam was introduced with respect to the (meth) acrylic block copolymer (3). About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

[Example 4]
250 g of (meth) acrylic block copolymer (3) was charged into an autoclave (glass reactor TEM-U1000N type capacity approximately 1 L manufactured by Heat Resistant Glass Industry Co., Ltd.). When this was heated to 120 ° C. with an autoclave heater, 120 ° C. superheated steam was directly added to the copolymer from the introduction tube inserted from the top of the autoclave, and the stirring blade was rotated at 400 rpm and stirred. Superheated steam was obtained by first sending pure water to a heat exchanger with a liquid feed pump and heating it. The introduction rate of superheated steam was controlled by a liquid feed pump and adjusted to 500 g / h. The gas discharged from the autoclave was condensed by blowing directly into 3 L of pure water cooled to 20 ° C. in a jacketed water tank. Superheated steam was introduced for 570 minutes, that is, 18 parts by weight of superheated steam was introduced to the (meth) acrylic block copolymer (3). About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

[Example 5]
In a stirring vessel (capacity: about 1 kL), 153 kg of (meth) acrylic block copolymer (3) was charged. When the inside was heated from the stirring kettle jacket and the temperature was raised to 160 ° C., 160 ° C. superheated steam was directly introduced into the copolymer from the bottom of the stirring kettle, and the stirring blade was rotated at 100 rpm for stirring. The superheated steam was obtained by first reducing the saturated steam generated in the boiler with a needle valve and adjusting the flow rate, and then heating it through a heat exchanger. The introduction rate of superheated steam was confirmed by a flow meter connected to the pipe and adjusted to 340 kg / h. The gas discharged from the stirring vessel was condensed by a condenser. Superheated steam was introduced for 240 minutes, that is, 8.9 parts by weight of superheated steam was introduced to the (meth) acrylic block copolymer (3). About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

[Example 6]
The (meth) acrylic block copolymer (3) was fed at 10 kg / h using a gear pump and continuously charged into a twin-screw extruder (Krupp Werner & Pfleiderer ZSK-25) together with 160 ° C superheated steam. Further, superheated steam was added from the upper part of the cylinder of the twin screw extruder, kneaded at a cylinder heating temperature of 160 ° C. and a screw rotation speed of 300 rpm, and continuously discharged. Superheated steam was obtained by first reducing the saturated steam generated by the steam generator with a needle valve and adjusting the flow rate, and then heating the piping to 160 ° C. with an induction heating device. The introduction rate of superheated steam was confirmed by the amount of pure water in the connected flow meter and steam generator tank, and adjusted to a total of 50 kg / h. The same treatment was repeated once again on the discharged sample. The gas discharged from the twin screw extruder was condensed by a condenser. Through the above treatment, 10 parts by weight of superheated steam was introduced to the (meth) acrylic block copolymer (3). About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

[Example 7]
The (meth) acrylic block copolymer (3) was fed at 20 kg / h using a gear pump and continuously charged into a twin-screw extruder (ZSK-25 manufactured by Krupp Werner & Pfleiderer) together with 250 ° C. superheated steam. The mixture was kneaded at a cylinder heating temperature of 250 ° C. and a screw rotation speed of 300 rpm, and continuously discharged. The superheated steam was obtained by first reducing the saturated steam generated by the steam generator and adjusting the flow rate with a needle valve, and then heating the pipe to 250 ° C. with an induction heating device. The introduction rate of superheated steam was confirmed by a connected flow meter and adjusted to a total of 7 kg / h. The gas discharged from the twin screw extruder was condensed by a condenser. Through the above treatment, 0.4 part by weight of superheated steam was introduced to the (meth) acrylic block copolymer (3). About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

[Example 8]
The (meth) acrylic block copolymer (4) is continuously charged at 5 kg / h into a twin screw extruder (ZSK-25 manufactured by Krupp Werner & Pfleiderer), and further heated at 180 ° C. from the upper part of the cylinder of the twin screw extruder. Water vapor was added, the mixture was kneaded at a cylinder heating temperature of 180 ° C. and a screw rotation speed of 300 rpm, and continuously discharged. Superheated steam was obtained by first reducing the saturated steam generated by the steam generator with a needle valve and adjusting the flow rate, and then heating the piping to 180 ° C. with an induction heating device. The introduction rate of superheated steam was confirmed by the amount of deionized water in the steam generator tank and adjusted to a total of 10 kg / h. The gas discharged from the twin screw extruder was condensed by a condenser. Through the above treatment, 2 parts by weight of superheated steam was introduced to the (meth) acrylic block copolymer (4). About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

[Comparative Example 1]
500 g of (meth) acrylic block copolymer (3) was charged into an autoclave (glass reactor TEM-U1000N type capacity approximately 1 L manufactured by Heat Resistant Glass Industry Co., Ltd.). When this was heated up to 160 ° C. with an autoclave heater, saturated steam at 100 ° C. was directly introduced into the copolymer from the introduction tube inserted from the top of the autoclave, and the stirring blade was rotated at 400 rpm and stirred. Saturated water vapor was decompressed and its flow rate adjusted with water vapor generated by a boiler using a needle valve. The introduction rate of saturated water vapor was adjusted to 500 g / h in advance by condensing the generated water vapor and measuring the weight. The gas discharged from the autoclave was condensed by blowing directly into 3 L of pure water cooled to 20 ° C. in a jacketed water tank. Saturated water vapor was introduced for 180 minutes, that is, 3 parts by weight of saturated water vapor was introduced to the (meth) acrylic block copolymer (3). About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

[Comparative Example 2]
The (meth) acrylic block copolymer (3) heated to 80 ° C. was fed at 10 kg / h using a gear pump, and a twin-screw extruder (ZSK-25 L / D = 42 manufactured by Krupp Werner & Pfleiderer) Were continuously added, kneaded at a cylinder heating temperature of 160 ° C. and a screw rotation speed of 300 rpm, and continuously discharged. The gas discharged from the twin screw extruder was condensed by a condenser. About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

[Comparative Example 3]
The (meth) acrylic block copolymer (3) was fed at 30 kg / h using a gear pump and continuously with a twin-screw extruder (Krupp Werner & Pfleiderer ZSK-25 L / D = 42) with 300 ° C. superheated steam. The mixture was kneaded at a cylinder heating temperature of 300 ° C. and a screw rotation speed of 300 rpm, and continuously discharged. The superheated steam was obtained by first reducing the saturated steam generated by the steam generator with a needle valve and adjusting the flow rate, and then heating the piping to 300 ° C. with an induction heating device. The introduction rate of superheated steam was confirmed by a connected flow meter and adjusted to a total of 4 kg / h. The gas discharged from the twin screw extruder was condensed by a condenser. Through the above treatment, 0.1 part by weight of superheated steam was introduced to the (meth) acrylic block copolymer (3). About the obtained copolymer, BHT content rate, molecular weight, and a moisture content evaluation result are shown in Table 1.

（メタ）アクリル系ブロック共重合体（２）および実施例２で得た（メタ）アクリル系ブロック共重合体のＢＨＴ含有率およびＵＶ硬化速度、耐熱性試験、耐光性試験の評価結果を表２に示す。

Table 2 shows the evaluation results of the BHT content, UV curing rate, heat resistance test, and light resistance test of the (meth) acrylic block copolymer (2) and the (meth) acrylic block copolymer obtained in Example 2. Shown in

From the test results of Table 2, it can be seen that when the BHT in the (meth) acrylic block copolymer is reduced to 0.08 wt%, the heat resistance and light resistance are improved.
About the (meth) acrylic block copolymer obtained in Examples 1-8, it turns out that BHT which all contain from Table 1 has fully reduced to 0.08 wt% or less. Moreover, since there is almost no change in the number average molecular weight and molecular weight distribution before and after the treatment, it can be seen that the deterioration of the (meth) acrylic block copolymer is suppressed. Moreover, about the (meth) acrylic-type block copolymer obtained in Example 2, it turns out that there is almost no fall of UV hardening rate from Table 2, and the fall of UV hardening performance is also suppressed.

About the (meth) acrylic-type block copolymer obtained by the comparative example 1, it turns out that BHT to contain has not fully decreased to 0.08 wt% or less. Moreover, it turns out that much moisture is contained.
For the (meth) acrylic block copolymer obtained in Comparative Example 2, it can be seen that BHT is not decreased at all.
As for the (meth) acrylic block copolymer obtained in Comparative Example 3, it can be seen that the number average molecular weight is decreased, the molecular weight distribution is increased, and the deterioration is progressing.

Claims (7)

Preparing a liquid polymer containing a volatile component in a production container;
Supplying superheated steam at 110 ° C. or higher into the production container, and contacting the superheated steam with the liquid material to remove volatile components under conditions where the total pressure of the production container is in the pressure range of 700 to 800 torr. A process for producing a purified polymer comprising:   The method for producing a purified polymer according to claim 1, wherein the volatile component is at least one selected from a residual solvent, a residual monomer, a residual component of a polymerization initiator system, and a decomposition product thereof.   The method for producing a purified polymer according to claim 1 or 2, wherein the boiling point of the volatile component exceeds 250 ° C.   The method for producing a purified polymer according to any one of claims 1 to 3, wherein the volatile component is 2,6-di-t-butyl-4-methylphenol.   The method for producing a purified polymer according to any one of claims 1 to 4, wherein the temperature of the liquid when supplying superheated steam is 110 ° C or higher.   The method for producing a purified polymer according to any one of claims 1 to 5, wherein superheated steam is supplied in an amount of 20 to 3000 parts by mass with respect to 100 parts by mass of the liquid.   The method for producing a purified polymer according to any one of claims 1 to 6, wherein the polymer is a (meth) acrylic block copolymer.