JP2006161003A - Vinyl ether/maleic anhydride-based copolymer and method for controlling open-ring ratio thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid state (such as a granule state) of a ring-opened copolymer (especially, partially ring-opened copolymer) of a vinyl ether/maleic anhydride copolymer by an easy method. <P>SOLUTION: A vinyl ether/maleic anhydride copolymer (such as a methyl vinyl ether/maleic anhydride copolymer) of a solid state (for example, a granule state) is subjected to the ring-opening treatment by the heating under moistening. The ring-opening treatment or the heat treatment may be carried out under the condition, for example, at a humidity of 50-99% RH and a temperature of 50-100°C. Such method can control freely and good precisely an open-ring ratio in the above ring-opened copolymer by adjusting the ring-opening treatment condition (the humidity, temperature, time, etc.). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ring-opening copolymer (or hydrolyzate) obtained by ring-opening (or hydrolyzing) a maleic anhydride unit of a vinyl ether-maleic anhydride copolymer (such as methyl vinyl ether-maleic anhydride copolymer), And a method for controlling the ring-opening rate of the ring-opening copolymer.

  Alkyl vinyl ether-maleic anhydride copolymer (VEMA) is a linear water-soluble polyelectrolyte compound, which is recently non-toxic to the human body, stable for a long period of time, adhesiveness, cohesiveness, water retention, Wide range of industrial fields such as adhesives (pastes), adhesives (denture adhesives, etc.), anti-fixing agents for detergents, hair styling agents, spray-type hair fixatives, builders for synthetic detergents, etc. It is applied in. Further, modified copolymers obtained by reacting this copolymer with various alcohols to esterify the maleic anhydride moiety are also used for these applications.

  Such an alkyl vinyl ether-maleic anhydride copolymer can improve or improve the solubility in water by opening (or hydrolyzing) the maleic anhydride moiety. Moreover, the partially ring-opening copolymer in which the maleic anhydride unit of VEMA is partially opened has both maleic anhydride and maleic anhydride parts, and has high reactivity derived from maleic anhydride. And features such as excellent solubility in water. For this reason, such a partially ring-opening copolymer is useful as a derivative reacted with various reagents. VEMA is ring-opened by dissolving in water, and 100% of maleic anhydride units can be ring-opened in an aqueous solution state. However, in VEMA, the maleic anhydride portion, which is a component in the copolymer, is an acid anhydride. Therefore, in order to use it by dissolving it in water, it is a water-soluble polymer, but high-temperature water (hot water). In the extreme case, for example, it was necessary to dissolve by stirring for a long time of about several days. Accordingly, various proposals have been made for ring opening of the maleic anhydride unit of VEMA.

  As a method for ring-opening VEMA with water, a method has been proposed in which an alkyl vinyl ether-maleic anhydride copolymer is dissolved in an organic solvent, and water is added to the resulting solution. For example, in Japanese Patent Publication No. 2957944 (Patent Document 1), maleic anhydride and excess vinyl alkyl ether are radically copolymerized in acetone using a specific polymerization initiator, and then reacted with alkanol or water. When forming a metal salt, it reacts with a metal hydroxide or oxide or a mixture thereof and the acetone is removed by distillation before, during or after ester formation or hydrolysis, or a monoalkyl ester of maleic acid Or the manufacturing method of the copolymer of maleic acid and its salt, and vinyl alkyl ether is indicated. According to this document, a maleic anhydride / vinyl alkyl ether copolymer can be hydrolyzed at about 50-70 ° C. by adding a large excess of water of 1000 mol% or more to the acetone solution of the copolymer. Furthermore, it is described that the produced aqueous solution of a metal salt of maleic acid / vinyl ether copolymer can be dehydrated into a solid with a constant weight by a conventional method.

  Japanese Patent Application Laid-Open No. 11-240921 (Patent Document 2) discloses a method for producing a high molecular weight polymer by radical solution polymerization of maleic anhydride and alkyl vinyl ether, based on the total amount of newly polymerized monomers. A process for polymerizing in the presence of 5 to 100% by weight of a prepolymerized maleic anhydride / C1-8 alkyl vinyl ether copolymer having a molecular weight of 100,000 to 10,000,000 daltons is disclosed. In this document, the resulting maleic anhydride / alkyl vinyl ether copolymer is hydrolyzed by adding water to an acetone solution of the polymer anhydride at about 50-70 ° C., after which the acetone is distilled off. It is described.

  However, in the methods described in these documents, it is difficult to remove organic solvents and unreacted components (maleic anhydride, etc.) at a high level, and the solid alkyl vinyl ether-maleic anhydride copolymer cannot be opened. It is difficult to obtain a ring copolymer. In addition, a process for removing acetone and the like after the ring opening is necessary, which complicates the operation and contributes to an increase in cost. Furthermore, when an attempt is made to obtain a solid copolymer by distilling off the solvent, the ring-opened maleic acid unit is ring-closed, and the ring-opening rate cannot be accurately controlled.

  On the other hand, in order to improve the solubility of alkyl vinyl ether / maleic anhydride copolymer in water, a method of forming a metal salt of alkyl vinyl ether / maleic anhydride copolymer, a method of half esterification by adding alcohol, and an addition of amine Also known is a method of half-amidation by the above method.

However, even in these methods, since the maleic acid unit is salt-formed, half-esterified, or half-amidated, a solid hydrolyzed alkyl vinyl ether-maleic anhydride copolymer ring-opening copolymer is obtained. Is difficult.
Japanese Patent Publication No. 2957794 (claims, paragraph numbers [0023] [0027]) JP-A-11-240921 (Claims, paragraph number [0028])

  Accordingly, an object of the present invention is to provide a ring-opening copolymer of vinyl ether-maleic anhydride copolymer (particularly a partially ring-opening copolymer) that can be ring-opened by a simple method even in a solid state (powdered form etc.) And providing a manufacturing method thereof.

  Another object of the present invention is to provide a method capable of freely and accurately controlling the ring opening rate of maleic anhydride units of a vinyl ether-maleic anhydride copolymer.

  Accordingly, the present inventors have conducted extensive studies to achieve the above-mentioned problems, and as a result, solid (particularly powdered) vinyl ether-maleic anhydride copolymer (copolymer of vinyl ether and maleic anhydride) under humidification. When the heat treatment is performed, a ring-opening copolymer (particularly a partial ring-opening copolymer) in which the maleic anhydride unit of the copolymer is ring-opened (or hydrolyzed) can be obtained simply and efficiently, The inventors have found that the ring-opening rate of the ring-opening copolymer can be accurately controlled by adjusting the processing conditions (humidity, heating temperature, processing time, etc.) of the copolymer, and the present invention has been completed.

That is, the solid ring-opening copolymer of the present invention (vinyl ether-maleic anhydride copolymer ring-opening copolymer) is a ring-opening in which the maleic anhydride unit of the vinyl ether-maleic anhydride copolymer is opened. A copolymer, which is a solid vinyl ether-maleic anhydride copolymer, is obtained by heat treatment under humidification (or heat-opening treatment under humidification). The vinyl ether may be an alkyl vinyl ether (for example, a C _1-30 alkyl vinyl ether such as methyl vinyl ether). The solid vinyl ether-maleic anhydride copolymer may have a granular shape. In the heat treatment, for example, the heat treatment may be performed under conditions of a humidity of about 50 to 99% RH and a temperature of about 50 to 100 ° C. In addition, the heat treatment may be performed for about 10 minutes to 5 hours under humidification. Exemplary ring-opening copolymers include a granular C _1-4 alkyl vinyl ether-maleic anhydride copolymer under conditions of humidity 70-95% RH and temperature 55-90 ° C. for 20 minutes to Ring-opening copolymers obtained by treatment for 4 hours are included.

  The ring-opening copolymer may be a partially ring-opening copolymer in which maleic anhydride units of the copolymer are partially opened. In such a partially ring-opening copolymer, The ring opening rate of the maleic anhydride unit of the coalescence may be about 20 to 97%. Further, the water content of the ring-opening copolymer may be, for example, 15% by weight or less.

  The ring-opening copolymer of the present invention can be usually produced by heating a solid vinyl ether-maleic anhydride copolymer under humidification to perform a ring-opening treatment.

  The ring-opening rate of the ring-opening copolymer can be accurately controlled by adjusting the ring-opening treatment or heat treatment conditions. Therefore, in the present invention, a solid vinyl ether-maleic anhydride copolymer is heated under humidification to perform a ring-opening treatment to obtain the ring-opening copolymer (that is, the production method), A method of controlling the ring-opening rate of the ring-opening copolymer by adjusting the ring-opening treatment conditions (for example, at least one of humidity, temperature and time) is also included. In such a method, the ring-opening rate may be controlled to 20 to 97%.

  In the methods described in Patent Documents 1 and 2 and the like, a partially ring-opening copolymer solution corresponding to the water concentration of the alkyl vinyl ether-maleic anhydride copolymer solution is obtained. And the ring-opening copolymer (partial ring-opening copolymer) of an alkyl vinyl ether-maleic anhydride copolymer can be obtained by applying the solution which added the water | moisture content obtained by these methods. For example, a ring-opening copolymer (partially opened) is obtained by distilling off a solvent such as acetone from an alkyl vinyl ether-maleic anhydride copolymer described in the above-mentioned patent document and the like and an organic solvent solution such as acetone containing water. Ring copolymer) can be obtained. However, such a method not only requires complicated operations for the production of the ring-opening copolymer, but also cannot remove organic solvents (such as acetone) at a high level. Is difficult to get. Furthermore, if the removal of the organic solvent or the like is attempted more completely, a ring-opening copolymer cannot be obtained with a desired ring-opening rate.

  According to the present invention, since a solid vinyl ether-maleic anhydride copolymer and heat treatment under humidification are combined, even if it is in a solid state (such as a granular form), a simple method can be used for vinyl ether-anhydride. A ring-opening copolymer of maleic acid copolymer (particularly a partial ring-opening copolymer) can be obtained. In the present invention, the ring-opening rate can be controlled freely and accurately by adjusting the heat treatment or ring-opening treatment conditions (humidity, temperature, treatment time, etc.).

  The ring-opening copolymer of the present invention is a solid ring-opening copolymer in which a maleic anhydride unit of a vinyl ether-maleic anhydride copolymer is opened, and the solid vinyl ether-maleic anhydride copolymer Can be obtained by heat treatment under humidification.

(Vinyl ether-maleic anhydride copolymer)
Examples of the vinyl ether include ethers of hydrocarbon groups and vinyl groups [eg, alkyl vinyl ethers, cycloalkyl vinyl ethers (C _5-10 cycloalkyl-vinyl ethers such as cyclohexyl vinyl ethers)], polyol monovinyl ethers, and the like. .

Examples of the alkyl vinyl ether include linear or branched C _1-30 alkyl-vinyl ethers (for example, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, t-butyl vinyl ether). , Sec-butyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether, etc., C _1-20 alkyl-vinyl ether, preferably C _1-10 alkyl-vinyl ether, more preferably C _1-6 alkyl -Vinyl ether).

In addition, the alkyl vinyl ether includes an alkyl vinyl ether having a substituent [for example, haloalkyl vinyl ether (halo C _1-20 alkyl-vinyl ether such as 2-chloroethyl vinyl ether, preferably halo C _1-10 alkyl-vinyl ether, more preferably halo C _1-6 alkyl-vinyl ether) and the like].

Monovinyl ethers of polyols include hydroxyalkyl vinyl ethers (eg, hydroxy C _1-20 alkyl-vinyl ethers such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, preferably hydroxy C _1-10 alkyl-vinyl ether, more preferably hydroxy C _1-6 alkyl-vinyl ether) and the like], polyalkylene glycol monovinyl ether (for example, poly C _2-4 alkylene glycol monovinyl ether such as diethylene glycol monovinyl ether and triethylene glycol vinyl ether) and the like.

Preferred vinyl ethers include alkyl vinyl ethers such as C _1-4 alkyl vinyl ethers (especially methyl vinyl ethers) which may have a substituent.

  In the vinyl ether-maleic anhydride copolymer (hereinafter sometimes referred to as VEMA, or simply a copolymer), the vinyl ethers may be used alone or in combination of two or more.

Among these vinyl ether-maleic anhydride copolymers, alkyl vinyl ether-maleic anhydride copolymers (for example, C _1-4 alkyl vinyl ether-maleic anhydride copolymers which may have a substituent, in particular, Methyl vinyl ether-maleic anhydride copolymer) is preferred.

  The vinyl ether-maleic anhydride copolymer may be a copolymer having at least monomer components of vinyl ether (vinyl ether monomer) and maleic anhydride, and may be other as long as the effects of the present invention are not impaired. A copolymer containing the copolymerizable monomer as a copolymerization component may be used.

  Moreover, as long as the said copolymer has a maleic anhydride unit, as needed, it may be partially esterified or amidated, and may form salts (metal salt etc.). Good.

  The vinyl ether-maleic anhydride copolymer may be a random copolymer or the like, but is usually an alternating copolymer of vinyl ether and maleic anhydride (completely alternating copolymer). That is, there are many random copolymers of maleic anhydride and other ethylene monomers, but the vinyl ether-maleic anhydride copolymer in the present invention usually does not include such a random copolymer. As described above, the alternating copolymer of vinyl ether and maleic anhydride is a water-soluble polymer that can be dissolved in water or a hydrophilic organic solvent. In addition, such a vinyl ether-maleic anhydride copolymer may usually be linear.

  In the copolymer, the ratio of maleic anhydride units is, for example, 0.8 to 1.2 mol, preferably 0.9 to 1.1 mol, more preferably 0.95, per 1 mol of vinyl ether unit. About 1.05 mol may be sufficient.

  The weight average molecular weight of the vinyl ether-maleic anhydride copolymer is not particularly limited, and is, for example, 50,000 or more (for example, about 50,000 to 3,000,000), preferably about 100,000 to 2,000,000, more preferably about 150,000 to 1,000,000 in terms of polystyrene. It may be.

  The shape of the copolymer may be solid, and may be usually granular (particle shape, fine particle shape, pellet shape, etc.). Such a solid or powdery copolymer may be spherical, ellipsoidal, columnar (such as prismatic), or amorphous. The average particle size of the powdery copolymer is, for example, 0.01 μm to 1 mm (for example, 0.03 to 800 μm), preferably 0.05 to 500 μm (for example, 0.08 to 300 μm), and more preferably. May be about 0.1 to 200 μm (for example, 0.2 to 100 μm), particularly about 0.3 to 80 μm (for example, 0.4 to 50 μm). In the present invention, the maleic anhydride unit of the copolymer can be ring-opened simply and efficiently by combining the solid (particularly powdered) copolymer and heat treatment under humidification.

  The vinyl ether-maleic anhydride copolymer as the raw material for the ring-opening copolymer may be a commercially available product or may be synthesized by a conventional method.

  Examples of the method for synthesizing the copolymer include precipitation by radical polymerization in a solvent (good solvent) capable of dissolving maleic anhydride and not dissolving vinyl ether-maleic anhydride copolymer (poor solvent). Examples thereof include a polymerization method and a solution polymerization method in which both maleic anhydride and maleic anhydride-vinyl ether copolymer are polymerized in a solvent (good solvent) in which both can be dissolved.

  Among these methods, from the viewpoint that a solid copolymer can be easily obtained, maleic anhydride and maleic anhydride in a solvent that is a good solvent for maleic anhydride and is a poor solvent for the copolymer. A vinyl ether-maleic anhydride copolymer obtained by the precipitation polymerization method in which vinyl ether is radically polymerized can be preferably used.

  The copolymer can be usually obtained by radical polymerization using an excess amount of vinyl ether relative to maleic anhydride.

  The solvent used for the synthesis of the copolymer can be appropriately selected according to the polymerization method. In the precipitation polymerization method, for example, hydrocarbons [for example, aromatic hydrocarbons (benzene, toluene, xylene, etc.), Aromatic hydrocarbons (eg, alkanes such as hexane, heptane, and octane), alicyclic hydrocarbons (eg, cycloalkanes such as cyclohexane), halogenated hydrocarbons (eg, dichloroethane, trichloroethane, tetrachloride) Carbon, haloalkanes such as 1,1,2-trichloro-1,2,2-trifluoroethane) and the like], ethers (such as allyl vinyl ether) and the like. In the solution polymerization method, esters (for example, acetate esters such as methyl acetate and ethyl acetate), ketones (for example, dialkyl ketones such as acetone and methyl ethyl ketone) and the like can be used. These solvents may be used alone or in combination of two or more.

  The polymerization initiator used for the polymerization is not particularly limited, and is a conventional initiator such as an organic peroxide (for example, acyl peroxides such as benzoyl peroxide and lauroyl peroxide, t-butyl peroxypivalate, etc. Peroxyesters), azo compounds (2,2′-azobisisobutyronitrile, etc.) and the like can be used. The polymerization initiators may be used alone or in combination of two or more.

  The polymerization may be performed at normal pressure or under pressure. Further, the polymerization may be carried out at room temperature or under heating (for example, about 40 to 120 ° C., preferably about 50 to 90 ° C.) depending on the type of the solvent and polymerization initiator, etc. Nitrogen, noble gas, etc.).

  The solid copolymer as the final product can be obtained by purifying the polymerization product obtained as described above by a method such as filtration and drying as appropriate according to the polymerization method. In addition, you may manufacture such a vinyl ether-maleic anhydride copolymer with reference to the method etc. which are described in Unexamined-Japanese-Patent No. 2003-40913, for example.

(Heat treatment or ring-opening treatment)
In the ring-opening copolymer of the present invention, the copolymer is heat-treated under humidification. That is, the ring-opening copolymer of the present invention can be obtained by heating the copolymer under humidification to perform a ring-opening treatment. In the heat treatment or ring-opening treatment, the copolymers may be used alone or in combination of two or more.

  The humidification condition is, for example, a humidity of 50% RH or more (for example, 50 to 99% RH), preferably 60 to 98% RH, more preferably 70 to 95% RH (for example, 80 to 93% RH). Also good. If the humidity is too low, it takes a long time to open the ring, and if the humidity is too high, it is difficult to control the humidity, so that precise control of the ring-opening copolymer may be difficult.

  In the heat treatment (or ring-opening treatment), the heating conditions can be selected from the range of 40 ° C. or higher (eg, 40 to 100 ° C.), for example, 45 ° C. or higher (eg, 45 to 100 ° C.), preferably 50 It may be higher than or equal to ° C (for example, 50 to 100 ° C), more preferably about 55 to 90 ° C.

  Further, the heat treatment time can be selected from a range of 5 minutes or more (for example, about 10 minutes to 5 hours) according to temperature, humidity, ring-opening rate, molecular weight (or polymerization degree) of the copolymer, etc. For example, it may be 15 minutes or longer (for example, 20 minutes to 4 hours), preferably 25 minutes to 3 hours (for example, 30 minutes to 2 hours), more preferably about 40 to 90 minutes. In the present invention, since the copolymer is treated under humidification and heating, the ring can be efficiently opened even in such a relatively short time treatment.

  As will be described later, the ring-opening rate of the ring-opening copolymer can be accurately controlled by adjusting these ring-opening treatment or heat treatment conditions (humidity, heating temperature, time, etc.).

  The heat treatment may be performed by leaving (or standing) the copolymer under the above humidification and heating, and in order to increase the contact efficiency with moisture, the copolymer (particularly a powdery copolymer) ) May be carried out by humidification and heating while stirring or mixing. In the case of stirring, the stirring speed may be, for example, 10 to 10,000 rpm, preferably 50 to 5000 rpm, more preferably about 100 to 1000 rpm.

  Note that the heat treatment can be performed using a humidifier having a conventional heating function, and such a humidifier may have a stirring or mixing function.

  In addition, in the ring-opening copolymer after the ring-opening treatment (heat treatment under humidification), excess water often remains, and such excess water increases the ring-opening rate. There is a fear. Therefore, after the ring-opening treatment, the ring-opening copolymer (or the copolymer) is preferably further subjected to a drying treatment at an appropriate temperature.

  In the drying process, the drying temperature (heating temperature) may be, for example, 40 ° C. or higher (for example, 40 to 200 ° C.), preferably 50 to 150 ° C., and more preferably about 60 to 100 ° C. In the drying treatment, the drying time may be, for example, 5 minutes or more (for example, 10 minutes to 5 hours), preferably 20 to 4 hours, and more preferably about 30 minutes to 2 hours.

(Ring-opening copolymer)
In the ring-opening copolymer of the copolymer obtained as described above, the maleic anhydride unit of the copolymer is ring-opened by hydrolysis. In such a ring-opening copolymer, it is sufficient that at least a part of all maleic anhydride units is ring-opened, and all the rings may be ring-opened (that is, the ring-opening rate is 100%).

  In the present invention, since a solid copolymer is used, the ring-opening rate (or hydrolysis rate) of maleic anhydride units can be adjusted easily and efficiently. Therefore, in the present invention, a partially ring-opened copolymer in which the maleic anhydride unit of the copolymer is partially opened can be obtained efficiently. Such a partially ring-opening copolymer has a maleic anhydride unit having a relatively high reactivity and a maleic acid unit having a ring opened, so that it can be used for various reactions and is soluble in water. Are better. Therefore, the partially ring-opening copolymer is a derivative obtained by reacting the remaining maleic anhydride unit (and maleic acid unit) with various reagents (for example, alcohols, amines, compounds having an epoxy group, etc.) It can be suitably used as a functional polymer).

  For the ring-opening rate (average ring-opening rate) of the ring-opening copolymer, the treatment conditions (temperature, humidity, time, etc.) are appropriately selected according to the molecular weight (or degree of polymerization) of the copolymer. For example, it can be selected from a range of 15% or more (for example, about 15 to 100%), for example, 15 to 99.5% (for example, 16 to 99%), preferably 18 to 98%, Preferably, it may be about 20 to 97% (for example, 30 to 90%).

  In the present specification, “ring-opening ratio” means a maleic anhydride copolymer in a vinyl ether-maleic anhydride copolymer (of the maleic anhydride unit of the copolymer). It means the ratio of acid units (ring-opening ratio or hydrolysis ratio) and is represented by the following formula.

[(X−Y) / X] × 100 (%)
(In the formula, X represents a maleic anhydride unit (mol) before ring opening, and Y represents a maleic anhydride unit (mol) after ring opening.)
In addition, the said ring-opening rate is obtained as an average ring-opening rate of the said whole ring-opening copolymer. That is, since the ring-opening copolymer heat-treats (or ring-opening treatment) the solid (particularly powdered) copolymer under humidification, it may usually have a ring-opening rate distribution. .

  In addition, the ring-opening copolymer is substantially free of impurities such as an organic solvent and the maleic anhydride unit is ring-opened because the solid-state copolymer is subjected to a ring-opening treatment under humidification and heating. Even high purity. Examples of such an organic solvent include organic solvents used in the preparation of the copolymer [ketones (for example, dialkyl ketones such as acetone and methyl ethyl ketone), carboxylic acid esters (for example, methyl acetate, ethyl acetate, and the like). Good solvents for the copolymers such as acetates, formates corresponding to these acetates, propionates, butyrate, etc .; hydrocarbons (aromatic hydrocarbons such as benzene, toluene, xylene, hexane, A poor solvent for the copolymer such as aliphatic or alicyclic hydrocarbons such as heptane, cyclohexane, etc.]. In the ring-opening copolymer, the content of such an organic solvent is, for example, 1% by weight or less (for example, 0 to 0.7% by weight), preferably 0.5% by weight or less (for example, 0 to 0%). .3% by weight), more preferably 0.1% by weight or less (for example, 0 to 0.05% by weight), particularly 0.01% by weight or less (for example, 0 to 0.005% by weight).

  Furthermore, the water content of the ring-opening copolymer is, for example, 20% by weight or less (for example, about 0.05 to 18% by weight), preferably 15% by weight or less (for example, 0.1 to 15% by weight). More preferably, it is about 0.5 to 13% by weight (for example, 1 to 12% by weight), particularly about 1.5 to 10% by weight (for example, 2 to 8% by weight).

  The shape of the ring-opening copolymer is solid corresponding to the copolymer, and may usually be granular (particulate, particulate, pellet, etc.). Such a solid or powdery ring-opening copolymer may be spherical, ellipsoidal, columnar (such as prismatic), or amorphous. The average particle size of the granular ring-opening copolymer is, for example, 1 μm to 1 mm (for example, 5 to 900 μm), preferably 10 to 800 μm (for example, 20 to 600 μm), and more preferably about 30 to 500 μm. There may be.

  The ring-opening rate of the ring-opening copolymer can be accurately controlled by adjusting the ring-opening treatment or heat treatment conditions. Therefore, in the present invention, a solid vinyl ether-maleic anhydride copolymer is heated under humidification to perform a ring-opening treatment to obtain the ring-opening copolymer (that is, the production method), A method of controlling the ring-opening rate of the ring-opening copolymer by adjusting the ring-opening treatment conditions is also included.

  In such a control method, for example, the ring-opening treatment condition (or heat treatment condition) is adjusted by adjusting at least one of humidity (humidification), temperature (heating temperature), and time (ring-opening treatment time). May be.

  Specifically, a relationship (relational expression) between predetermined ring-opening treatment conditions (at least one condition selected from humidity, temperature, and time) and the ring-opening rate of the ring-opening copolymer is obtained in advance, The ring opening rate may be controlled using the relationship. Such a relational expression is obtained by, for example, sampling a part of the copolymer in advance and measuring the ring-opening rate when heat-treated under a predetermined condition, and from these measured values, the ring-opening rate and the ring-opening treatment It can be obtained by deriving a relationship (relational expression) with the condition. Note that the relational expression may be derived using a statistical method, and the ring opening rate is measured for a plurality of [at least 2 or more (for example, about 2 to 10)] sampling. You may derive using.

  In such a method, the ring-opening rate can be accurately controlled within the range (for example, 20 to 99%).

  Since the ring-opening copolymer of the vinyl ether-maleic anhydride copolymer of the present invention is solid and the maleic anhydride unit is ring-opened, it can be used in a wide range of applications. In addition to being water-soluble, it is excellent in non-toxicity to the human body, long-term stability, adhesiveness, cohesiveness, water retention, releasability and the like. In particular, the partially ring-opening copolymer of the present invention can impart various functions by utilizing the relatively high reactivity of the remaining maleic anhydride. Therefore, the ring-opening copolymer of the present invention includes, for example, a patch (a patch), an adhesive (such as a denture adhesive), a thickener, a binder such as an ink or a paint, a hair styling agent (a hair gel, a hair lotion, Can be used in a wide range of applications such as spray-type hair fixatives, detergent anti-sticking agents, and synthetic detergent builders.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

  In addition, the ring-opening rate and the water content (water content) of the ring-opening copolymer of the methyl vinyl ether-maleic anhydride copolymer obtained in Examples and Comparative Examples were measured as follows.

[Opening rate]
1 g of alkyl vinyl ether-maleic anhydride copolymer obtained in Examples and Comparative Examples was placed in a small flask, and 1.3 g of aniline was added dropwise thereto. Then, after stirring and heating at 50 ° C. for 90 minutes, alkyl vinyl ether-anhydrous maleic acid reacted with aniline using 50 ml of a mixed solution of ethylene glycol and 2-propanol (the former / the latter (weight ratio) = 1/1). The acid copolymer was quantitatively transferred to a beaker and subjected to potentiometric titration with 0.2N hydrochloric acid using an automatic potentiometric titrator (“AT-510”, manufactured by Kyoto Electronics Industry Co., Ltd.) Was measured.

[Moisture percentage]
The moisture content was measured using a halogen moisture meter (“HB-43”, manufactured by METTLER TOLEDO).

  The methyl vinyl ether-maleic anhydride copolymer (“VEMA A-103”, manufactured by Daicel Chemical Industries, Ltd.) used in Examples and Comparative Examples has a ring opening rate of 13% and a moisture content of 2. It was 1% by weight.

Example 1
20 kg of methyl vinyl ether-maleic anhydride copolymer (VEMA A-103, manufactured by Daicel Chemical Industries, Ltd.) with a heating / humidifying function (Laedige Mixer, “FKM-50D”, manufactured by Matsubo Corporation) And stirred for 60 minutes in an environment of 80 ° C. and 90% RH. Furthermore, it was dried without humidification at 80 ° C. for 1 hour. The resulting methyl vinyl ether-maleic anhydride copolymer (partial ring-opening copolymer) had a ring opening rate of 94% and a moisture content of 10.3% by weight.

(Example 2)
20 kg of a methyl vinyl ether-maleic anhydride copolymer (“VEMA A-103”, manufactured by Daicel Chemical Industries, Ltd.) with a heating / humidifying function (Reedige mixer, “FKM-50D”, Matsubo Co., Ltd.) And stirred for 60 minutes in an environment of 60 ° C. and 85% RH. Furthermore, it was dried without humidification at 80 ° C. for 1 hour. The resulting methyl vinyl ether-maleic anhydride copolymer had a ring opening rate of 61% and a moisture content of 9.1% by weight.

(Example 3)
20 kg of methyl vinyl ether-maleic anhydride copolymer (“VEMA A-103”, manufactured by Daicel Chemical Industries, Ltd.) And stirred for 60 minutes in an environment of 60 ° C. and 70% RH. Furthermore, it was dried without humidification at 80 ° C. for 1 hour. The resulting methyl vinyl ether-maleic anhydride copolymer had a ring-opening rate of 25% and a moisture content of 5.3% by weight.

(Comparative Example 1)
20 kg of methyl vinyl ether-maleic anhydride copolymer (“VEMA A-103”, manufactured by Daicel Chemical Industries, Ltd.) The mixture was stirred for 60 minutes at room temperature (20 ° C.) and 90% RH without heating. Furthermore, it was dried without humidification at 80 ° C. for 1 hour. The resulting methyl vinyl ether-maleic anhydride copolymer had a ring opening rate of 14% and a moisture content of 2.5% by weight.

(Comparative Example 2)
20 kg of methyl vinyl ether-maleic anhydride copolymer (“VEMA A-103”, manufactured by Daicel Chemical Industries, Ltd.) And stirred for 60 minutes without humidification in an environment of 80 ° C. Furthermore, it was dried without humidification at 80 ° C. for 1 hour. The resulting methyl vinyl ether-maleic anhydride copolymer had a ring opening rate of 12% and a moisture content of 1.4% by weight.

  Table 1 below shows the ring-opening conditions, the ring-opening rate, and the moisture content of the partially ring-opened copolymers of methyl vinyl ether-maleic anhydride copolymer obtained in Examples and Comparative Examples.

  As is clear from Table 1, in Examples 1 to 3, a high ring-opening rate was obtained by adjusting the temperature and humidity. On the other hand, in Comparative Example 1, since the humidity was high but the temperature was low, the ring could hardly be opened. In Comparative Example 2, although the temperature was high, the ring could hardly be opened similarly because of the low humidity.

Example 4
20 kg of a methyl vinyl ether-maleic anhydride copolymer (“VEMA A-103”, weight average molecular weight of about 500,000, manufactured by Daicel Chemical Industries, Ltd.) ”, Manufactured by Matsubo Co., Ltd.), and agitated in an environment of 80 ° C. and 90% RH for the predetermined ring-opening treatment time shown in Table 2. Furthermore, it was dried without humidification at 80 ° C. for 1 hour. And the ring-opening rate of the obtained methyl vinyl ether-maleic anhydride copolymer was measured in each time, and the relationship between ring-opening processing time and ring-opening rate was investigated. The results are shown in Table 2.

(Example 5)
20 kg of a methyl vinyl ether-maleic anhydride copolymer (“VEMA A-105H6”, weight average molecular weight of about 1,000,000, manufactured by Daicel Chemical Industries, Ltd.) with a heating / humidifying function mixer (Laedige mixer, “FKM-50D”) ”, Manufactured by Matsubo Co., Ltd.), and agitated in an environment of 80 ° C. and 90% RH for the predetermined ring-opening treatment time shown in Table 2. Furthermore, it was dried without humidification at 80 ° C. for 1 hour. And at each time, the ring-opening rate of the obtained methyl vinyl ether-maleic anhydride copolymer was measured, and the relationship between the ring-opening treatment time and the ring-opening rate was examined. The results are shown in Table 2.

  As is clear from Table 2, it was found that in the methyl vinyl ether-maleic anhydride copolymer used in Examples 4 and 5, the ring opening rate can be controlled by adjusting the ring opening treatment time. In addition, as is clear from the comparison between Example 4 and Example 5, the ring-opening rate differs due to the difference in molecular weight (or polymerization degree) even at the same ring-opening treatment time (and temperature / humidity). I understood it.

Claims (12)

  A ring-opening copolymer in which a maleic anhydride unit of a vinyl ether-maleic anhydride copolymer is ring-opened, which is obtained by heat-treating a solid vinyl ether-maleic anhydride copolymer under humidification Ring-opening copolymer.   The ring-opening copolymer according to claim 1, wherein the vinyl ether is an alkyl vinyl ether.   The ring-opening copolymer according to claim 1, wherein the solid vinyl ether-maleic anhydride copolymer is in the form of a powder.   The ring-opening copolymer according to claim 1, obtained by treatment under conditions of a humidity of 50 to 99% RH and a temperature of 50 to 100 ° C.   The ring-opening copolymer according to claim 1, obtained by heat treatment for 10 minutes to 5 hours under humidification. The powdered C _1-4 alkyl vinyl ether-maleic anhydride copolymer is obtained by treating for 20 minutes to 4 hours under conditions of a humidity of 70 to 95% RH and a temperature of 55 to 90 ° C. Ring-opening copolymer.   2. The ring-opening copolymer according to claim 1, which is a partially ring-opening copolymer in which the maleic anhydride unit of the copolymer is partially opened.   The ring-opening copolymer according to claim 1, wherein the ring-opening rate of maleic anhydride units of the copolymer is 20 to 97%.   The ring-opening copolymer according to claim 1, wherein the water content is 15% by weight or less.   The method for producing a ring-opening copolymer according to claim 1, wherein the solid vinyl ether-maleic anhydride copolymer is heated under humidification to perform a ring-opening treatment.   The method for obtaining a ring-opening copolymer according to claim 1, wherein the solid vinyl ether-maleic anhydride copolymer is heated under humidification to perform a ring-opening treatment, and by adjusting the ring-opening treatment conditions, A method for controlling the ring-opening rate of the ring-opening copolymer.   The method according to claim 11, wherein the ring opening rate is controlled to 20 to 97%.