JP2008239850A - Method for producing copolymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for taking out fine particles in slurry obtained by a precipitation polymerization by granulating them to a size of a good handling property by a simple method. <P>SOLUTION: This method for producing a copolymer comprising (I) a polymerization process and (II) a granulation process in producing (A) the copolymer containing (i) an acrylic monomer unit containing a carboxy group by copolymerizing a monomer mixture containing the carboxy group-containing acrylic monomer and another acrylic monomer copolymerizable with the above is characterized by, in the granulation process (II), adding (C) a solvent to the copolymer slurry solution obtained in the polymerization process (I) additionally, agitating at 50 to 120°C temperature and then solid-liquid separating to obtain the copolymer (A). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention produces a copolymer containing a carboxyl group-containing acrylic monomer unit having a precisely controlled copolymer composition and molecular weight distribution in a specific polymerization solvent, followed by addition of a specific solvent. Then, the present invention relates to a production method in which fine particles of the copolymer are agitated at a specific temperature and taken out as particles having a size excellent in handling properties.

  Polymethyl methacrylate (hereinafter also referred to as PMMA resin), (meth) acrylic acid ester monomer copolymer (also referred to as AC resin), polystyrene (hereinafter also referred to as PS resin), acrylonitrile-styrene copolymer (hereinafter referred to as AS) Resin), acrylonitrile-styrene-butadiene resin (hereinafter also referred to as ABS resin) and the like are generally produced by bulk polymerization, suspension polymerization, emulsion polymerization when industrially produced. A small portion is produced by solution polymerization.

  Bulk polymerization, suspension polymerization, and emulsion polymerization are convenient production methods for mass production, but it is difficult to control the copolymer composition and molecular weight distribution, as can be easily inferred from the polymerization mode. Many. Furthermore, in a polymerization method using water as a medium such as suspension polymerization and emulsion polymerization, an unsaturated monomer having a carboxyl group such as methacrylic acid, acrylic acid, maleic anhydride, and itaconic acid is copolymerized. It is difficult to impart functionality and compatibility with other polymers to the polymer, and it is difficult to improve the physical and chemical properties as a functional polymer and as a polymer alloy. I was trying. Furthermore, in bulk polymerization, suspension polymerization, and emulsion polymerization, it is very difficult to control the polymerization rate, and it is difficult to suppress the formation of a macromolecular polymer. For this reason, in the polymer, these macromolecular polymers are mixed as foreign matters, and when a film or a molded product is formed, there are cases where defects (such as fish and fish eyes) having the macromolecular polymer as a nucleus occur. Therefore, polymers produced by bulk polymerization, suspension polymerization, and emulsion polymerization have a problem that their use is limited in optical applications that require high transparency and uniformity.

  On the other hand, in solution polymerization, control of the copolymer composition and molecular weight distribution is relatively easy, and copolymerization of the unsaturated monomer having the water-soluble functional group is also possible. It was very difficult to separate and recover from the solution, and there was a problem that much labor and energy were required.

  As a method for solving such a problem, a monomer mixture containing a carboxyl group-containing acrylic monomer and another acrylic monomer copolymerizable therewith is copolymerized to obtain a carboxyl group-containing acrylic monomer. In the production of a copolymer containing a body unit, a technique is known in which a monomer mixture is mixed and copolymerized in an organic solvent having a copolymer solubility of 1/100 g or less to obtain a copolymer slurry. (See Patent Document 1). In addition, the technique disclosed in Patent Document 1 separates the slurry of the copolymer obtained in the polymerization step into solid and liquid, and adds water to the obtained cake of copolymer, Washing is performed at a temperature, and solid-liquid separation is performed again at 50 to 120 ° C. from the cleaning liquid. Through this polymerization process and washing process, the molecular weight distribution and composition distribution of the copolymer are controlled in the same way as in the solution polymerization method, and contamination with foreign substances (insoluble and infusible macromolecular polymers, homopolymers of raw material monomers) is minimized. Furthermore, the copolymer (A) obtained is excellent in handling properties and thermal stability.

In addition, the resin-containing solution is obtained by reacting one or a plurality of raw material compounds in the presence of an organic solvent, and the resin-containing solution is added in a solvent different from the organic solvent to precipitate the resin. A technique for heating the deposited slurry is also disclosed (see Patent Document 2).
JP 2006-265543 A JP 2002-201220 A

  As in Patent Document 1, water is added to the copolymer cake and washed at a temperature of 50 to 120 ° C., so that the particles are granulated to a size with good handling properties. It is necessary to solid-liquid separate the polymer slurry once and take out the copolymer as a cake, and the process is complicated. Further, since a large amount of water is added to the copolymer cake, there is a problem that a large amount of water containing an organic solvent is generated as waste water.

  In addition, the method of Patent Document 2 is a method in which a solution in which a resin is dissolved is added to a poor solvent to precipitate the resin, and then heated and stirred. Increase in size.

  Accordingly, an object of the present invention is to copolymerize a monomer mixture containing a carboxyl group-containing acrylic monomer and another acrylic monomer copolymerizable therewith, and to obtain a carboxyl group-containing acrylic monomer unit. In the polymerization process, the molecular weight distribution and the composition distribution are controlled in the polymerization process, and the copolymer particles are granulated into a size with good handling properties by a simple method. .

  As a result of intensive studies to solve the above problems, the present inventors have obtained a copolymer obtained by a reaction in a specific polymerization solvent when producing a copolymer containing a carboxyl group-containing acrylic unit. After adding a specific solvent to the slurry, it was found that the fine particles of the copolymer can be granulated into particles with good handling properties by stirring at a specific temperature, and the present invention has been reached. did.

That is, the present invention
[1] Copolymerizing a monomer mixture containing (i) a carboxyl group-containing acrylic monomer and another acrylic monomer copolymerizable therewith, and (i) a carboxyl group-containing acrylic monomer A method for producing a copolymer, which comprises the following polymerization step (I) and granulation step (II) when producing a copolymer (A) containing units.
(I) Polymerization Step An organic solvent containing no aromatic group, the monomer mixture containing a carboxyl group-containing acrylic monomer and other acrylic monomers copolymerizable therewith is dissolved, and (I) Polymerization step (II) in which a copolymer slurry containing a carboxyl group-containing acrylic monomer unit is copolymerized in an organic solvent (B) having a solubility of 1 g / 100 g or less to obtain a copolymer slurry. Granulation step A solvent (C) is added to the copolymer slurry solution, and the mixture is stirred at a temperature of 50 to 120 ° C, followed by solid-liquid separation to obtain particles of the copolymer (A) [2 The addition method of the said solvent (C) is 0.01 to 10 weight% of the said organic solvent (B), The manufacturing method of the copolymer as described in [1] characterized by the above-mentioned.
[3] The method for producing a copolymer according to [1] or [2], wherein the organic solvent (B) is at least one selected from aliphatic hydrocarbons, carboxylic acid esters, and ketones.
[4] The method for producing a copolymer according to any one of [1] to [3], wherein the organic solvent (B) is a mixture of an aliphatic hydrocarbon and a carboxylic acid ester.
[5] The copolymer according to [4], wherein the organic solvent (B) is a mixture of an aliphatic hydrocarbon and a carboxylic acid ester, and the weight ratio thereof is 5/95 to 70/30. Manufacturing method.
[6] The method for producing a copolymer according to any one of [1] to [5], wherein the solvent (C) is a carboxylic acid ester and / or water.
[7] The polymerization step (I) is performed under the condition that the absolute value (ΔSP) of the difference between the solubility parameter of the copolymer (A) and the solubility parameter of the organic solvent (B) is 1.0 or more. The method for producing a copolymer according to any one of [1] to [6].
[8] The copolymer (A) is (i) a carboxyl group-containing acrylic monomer unit represented by the following general formula (1) and (ii) an acrylic single unit represented by the following general formula (2). It is a copolymer containing a monomer unit, The manufacturing method of the copolymer in any one of [1]-[7] characterized by the above-mentioned.

(However, R ¹ is the same or different and represents any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms.)

(However, R ² represents any one selected from hydrogen and an alkyl group having 1 to 5 carbon atoms, and R ³ is an unsubstituted or substituted C 1-6 aliphatic hydrocarbon group and carbon having a hydroxyl group or halogen. Any one selected from alicyclic hydrocarbon groups of 3 to 6)
[9] The copolymer according to [8], wherein the copolymer (A) contains (i) 15 to 50% by weight of a carboxyl group-containing acrylic monomer unit represented by the general formula (1). Manufacturing method of coalescence.
[10] After producing the copolymer (A) by the method for producing a copolymer according to [8] or [9] (first step), the copolymer (A) is subsequently heat-treated, (Ii) A step of performing an intramolecular cyclization reaction by dehydration and / or (b) dealcoholization reaction (second step), (iii) a glutaric anhydride unit represented by the following general formula (3) and (ii) ) A method for producing a glutaric anhydride unit-containing thermoplastic copolymer, which comprises producing a thermoplastic copolymer (D) containing an unsaturated carboxylic acid alkyl ester unit.

(However, R ⁴ and R ⁵ are the same or different and represent any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms.)

According to the present invention, when producing a copolymer containing a carboxyl group-containing acrylic unit, a specific solvent is added to a copolymer slurry obtained by a reaction in a specific polymerization solvent, and a specific solvent is further added. By stirring at a temperature, the copolymer particles can be granulated to a size with good handleability and taken out.

  Hereinafter, the manufacturing method of the carboxyl group-containing acrylic copolymer (A) of the present invention will be specifically described.

  In the present invention, the carboxyl group-containing acrylic copolymer (A) is a polymerization step (I) for producing an organic solvent slurry containing the copolymer slurry, and a specific solvent is added to the slurry and stirred at a specific temperature. Then, it can manufacture by the granulation process (II) which carries out solid-liquid separation and obtains a copolymer (A).

  The carboxyl group-containing acrylic copolymer (A) produced in the present invention is not particularly limited as long as it is obtained by copolymerizing a carboxyl group-containing acrylic monomer, and the carboxyl group-containing acrylic monomer The body can use any carboxyl group-containing acrylic monomer that can be copolymerized with other acrylic monomers. As a preferable carboxyl group-containing acrylic monomer, the following general formula (4)

(However, R ⁶ represents any one selected from hydrogen and an alkyl group having 1 to 5 carbon atoms)
In particular, acrylic acid and methacrylic acid are preferred, and methacrylic acid is more preferred from the viewpoint of excellent thermal stability. These can be used alone or in combination.

  Other acrylic monomers copolymerizable with the carboxyl group-containing acrylic monomer used in the present invention include methyl acrylate, ethyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylic Benzyl acid, 2-ethylhexyl acrylate, lauryl acrylate, dodecyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, benzyl methacrylate, lauryl methacrylate, dodecyl methacrylate, tri Examples thereof include acrylic acid esters such as fluoroethyl methacrylate, methacrylic acid esters, and their (fluoro) alkyl ester monomers. Among these, from the viewpoint of excellent optical characteristics and thermal stability, alkyl methacrylates and alkyl acrylates are preferable, methyl methacrylate and ethyl methacrylate are more preferable, and methyl methacrylate is particularly preferable. These may be used alone or as a mixture of two or more.

  If necessary, in addition to the acrylic monomer, other vinyl monomers that can be copolymerized, such as vinyl acetate, vinyl benzoate, styrene, α-methylstyrene, and acrylonitrile may be used. . These other unsaturated monomers may be used alone or as a mixture of two or more.

  Moreover, the copolymer (A) containing the carboxyl group-containing acrylic monomer unit of the present invention contains the aforementioned carboxyl group-containing acrylic monomer and other acrylic monomers copolymerizable therewith. (I) a carboxyl group-containing acrylic monomer unit represented by the following general formula (1) and (ii) an acrylic represented by the following general formula (2). It is a copolymer containing a monomer unit.

(However, R ¹ is the same or different and represents any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms.)

(However, R ² represents any one selected from hydrogen and an alkyl group having 1 to 5 carbon atoms, and R ³ is an unsubstituted or substituted C 1-6 aliphatic hydrocarbon group and carbon having a hydroxyl group or halogen. Any one selected from alicyclic hydrocarbon groups of 3 to 6)
The carboxyl group-containing acrylic copolymer (A) improves the pigment dispersibility of ordinary acrylic polymers and improves the compatibility with polymers such as nylon (hereinafter also referred to as NY) and polycarbonate (hereinafter also referred to as PC). This makes it possible to realize a functional polymer alloy. Furthermore, it functions as an effective functional group for imparting photosensitivity and developability to the acrylic polymer by a polymer reaction utilizing a carboxyl group. Further, the heat resistance can be improved and the refractive index can be adjusted by utilizing the intramolecular reaction of the acrylic polymer.

  The carboxyl group-containing acrylic monomer is copolymerized in such an amount that the acid value of the carboxyl group-containing acrylic copolymer (A) is preferably 5 to 300 mgKOH, more preferably 5 to 250 mgKOH. desirable. And it is desirable to contain 15 to 50 weight% of carboxyl group-containing acrylic monomer units in the copolymer (A).

  The polymerization step (I) in the production method of the present invention is an organic solvent that does not contain an aromatic group and includes a raw material, an unsaturated carboxylic acid alkyl ester monomer and an unsaturated carboxylic acid monomer. A body mixture melt | dissolves and the said monomer mixture is copolymerized in the organic solvent (B) whose solubility of a copolymer (A) is 1 g / 100 g or less, and obtains a copolymer slurry. In the polymerization step (I), a monomer mixture containing a carboxyl group-containing acrylic monomer as a raw material is dissolved, and (i) the solubility of the carboxyl group-containing acrylic copolymer (A) is 1 g / 100 g or less. It is characterized by using an organic solvent (B) characterized in that it is a so-called “precipitation polymerization method” in which the carboxyl group-containing acrylic copolymer (A) is precipitated. Here, the “solubility of the carboxyl group-containing acrylic copolymer (A)” means that after stirring for 24 hours at 23 ° C. with respect to 100 g of the organic solvent (B) of the carboxyl group-containing acrylic copolymer (A). This means the amount of dissolution.

  As the organic solvent (B) used in the present invention, it is necessary that the above-described precipitation polymerization method is possible and further no aromatics are contained. Specific examples include one or more selected from aliphatic hydrocarbons, carboxylic acid esters, ketones, ethers, and alcohols. Among these, one or more selected from aliphatic hydrocarbons, carboxylic acid esters, and ketones are preferable. In particular, one or more selected from aliphatic hydrocarbons and carboxylic acid esters are preferred.

  Examples of the aliphatic hydrocarbon used in the present invention include a linear hydrocarbon having 5 to 10 carbon atoms, an aliphatic hydrocarbon having a side chain, and an alicyclic hydrocarbon. Specific examples include n-pentane, n-hexane, cyclohexane, n-heptane, n-octane, n-nonane, n-decane and various isomers thereof.

  Examples of the carboxylic acid ester preferably used in the present invention include an ester composed of a saturated aliphatic carboxylic acid and a saturated alcohol. Specific examples of the saturated carboxylic acid include formic acid, acetic acid, propionic acid, butyric acid, Moreover, as a saturated alcohol, a C1-C10 linear and branched thing can be mentioned. Preferred carboxylic acid esters include formic acid-n-propyl, isopropyl formate, formic acid-n-butyl, formic acid isobutyl, formic acid-n-pentyl, formic acid-n-hexyl, acetic acid-n-propyl, isopropyl acetate, acetic acid-n- Butyl, isobutyl acetate, acetic acid-n-pentyl, acetic acid-n-hexyl, acetic acid-n-heptyl, acetic acid-n-octyl, acetic acid-n-nonyl, methyl propionate, ethyl propionate, propionate-n-propyl, Isopropyl propionate, n-butyl propionate, isobutyl propionate, n-pentyl propionate, n-hexyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butyl butyrate, Various different types such as isobutyl butyrate, n-pentyl butyrate, n-hexyl butyrate Mention may be made of the body.

  The ketone used in the present invention is a ketone having 1 to 10 carbon atoms and a linear and branched saturated aliphatic group. Specific examples include methyl-n-butyl ketone, methyl isobutyl ketone, and ethyl isobutyl. Examples include ketones.

  Among these, in the present invention, a mixture of an aliphatic hydrocarbon and a carboxylic acid ester can be preferably used. In this case, the preferred mixing ratio of the aliphatic hydrocarbon and the carboxylic acid ester is not particularly limited, but is preferably in the range of 5/95 to 70/30 by weight, and more preferably in the range of 10/90 to 50/50. In particular, the range of 20/80 to 40/60 is preferable. When the mixing ratio is less than 5/95, the copolymer formed during the polymerization tends to stick to the reaction vessel. Moreover, when the mixing ratio is greater than 70/30, it tends to be difficult to precisely control the copolymer composition.

  In addition, when precipitation polymerization is performed in the production method of the present invention, if water is used in the polymerization reaction system, the copolymer composition may be difficult to precisely control, and water should be kept within the controllable range of the copolymer composition. Most preferably, water is not positively added unless the component used in the polymerization reaction system such as an organic solvent contains a very small amount of water as an impurity.

  The polymerization temperature can be arbitrarily set, but is preferably a temperature not higher than the boiling point of the organic solvent to be used. Among these, it is preferable to perform polymerization at a polymerization temperature of 100 ° C. or lower, and it is more preferable to perform polymerization at a polymerization temperature of 90 ° C. or lower. The lower limit of the polymerization temperature is not particularly limited as long as the polymerization proceeds, but is usually 50 ° C. or higher, preferably 60 ° C. or higher from the viewpoint of productivity considering the polymerization rate. The polymerization time is not particularly limited as long as it is a time sufficient to obtain a necessary polymerization rate, but is preferably in the range of 60 to 360 minutes, and particularly preferably in the range of 90 to 240 minutes from the viewpoint of production efficiency.

  Moreover, it is preferable to control the dissolved oxygen concentration in the polymerization liquid to 5 ppm or less from the viewpoint of improving the thermal stability of the carboxyl group-containing acrylic copolymer (A). A more preferable range of dissolved oxygen concentration is 0.01 to 3 ppm, and further preferably 0.01 to 1 ppm. Here, the dissolved oxygen concentration in the present invention is a value obtained by measuring dissolved oxygen in the polymerization solution using a dissolved oxygen meter (for example, DO meter B-505 manufactured by Iijima Electronics Co., Ltd., which is a galvanic oxygen sensor). is there. For the method of reducing the dissolved oxygen concentration to 5 ppm or less, a method of passing an inert gas such as nitrogen, argon or helium into the polymerization vessel, a method of bubbling an inert gas directly into the polymerization solution, or an inert gas before starting the polymerization A method of performing pressure relief once or twice after filling the polymerization vessel, a method of degassing the closed polymerization vessel before charging the monomer mixture, and then filling with an inert gas, A method of passing an inert gas through the polymerization vessel can be exemplified.

  A preferred ratio of the monomer mixture used in the production of the carboxyl group-containing acrylic copolymer (A) is such that the monomer mixture is 100% by weight and the carboxyl group-containing acrylic monomer is 15 to 50% by weight. %, More preferably 20 to 45% by weight. When the copolymerization amount of the carboxyl group-containing acrylic monomer is less than 15% by weight, modification by copolymerization and development to a polymer reaction or the like may be difficult. When the copolymerization amount of the carboxyl group-containing acrylic monomer exceeds 50% by weight, the control of the copolymer composition and the control of the molecular weight distribution tend to deviate from those desired. In addition, when a polymer reaction is performed and it is considered to be used as a photosensitive resin, the affinity or hydrogen bonding property with the pigment becomes too strong, and pigment seeding (aggregation) may occur easily. is there. In addition, the sensitivity difference between the exposed portion and the unexposed portion with respect to the developer tends to be small, and it is difficult to form a fine and clear development pattern.

  In addition, these monomer mixtures may be charged in an organic solvent at once and copolymerized, or may be copolymerized while being added in portions or sequentially. More preferably, for the purpose of reducing the composition distribution of the monomer units constituting the carboxyl group-containing acrylic copolymer (A) to be formed, the weight composition ratio in the monomer mixture is arbitrarily set, and divided additions are made. Or the method of adding sequentially is mentioned.

  Copolymerization can be carried out in the presence or absence of a polymerization initiator, but is preferably carried out in the presence of a polymerization initiator. As the polymerization initiator, it is preferable to use a radical polymerization initiator, and as the radical polymerization initiator, any commonly used initiator can be used, among which 2,2′-azobisisobutyronitrile, Azo such as 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis-2-methylbutyronitrile Compounds, lauroyl peroxide, benzoyl peroxide, t-butylperoxyneodecanate, t-butylperoxypivalate, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, dicumyl An organic peroxide such as peroxide can be preferably used.

  The amount of the polymerization initiator used is preferably 0.001 to 2.0 parts by weight, particularly 0.01 to 1.0 part by weight, based on 100 parts by weight of the monomer mixture used for copolymerization. .

  In the present invention, a chain transfer agent such as alkyl mercaptan, carbon tetrachloride, carbon tetrabromide, dimethylacetamide, dimethylformamide, and triethylamine can be added for the purpose of controlling the molecular weight.

  In the present invention, it is necessary to consider the balance of solubility in the carboxyl group-containing acrylic copolymer (A) and the organic solvent (B) in order to easily precipitate and deposit the carboxyl group-containing acrylic copolymer (A). . From this point of view, it is preferable to design polymerization conditions such as copolymer species, copolymer composition, and reaction solvent in consideration of solubility parameters of each component.

  The solubility parameter δp of the carboxyl group-containing acrylic copolymer (A) is preferably in the range of 7.0 to 12.0, and more preferably 7.5 to 10.5. When δp is less than 7.0, the gasoline resistance and oil resistance are inferior, and there are cases where many practical limitations are imposed. When δp exceeds 12.0, the cohesive force of the polymer becomes too strong, and when processed into a molded product or dissolved and used, the viscosity becomes too high and the handleability tends to deteriorate.

  The solubility parameter mentioned here is calculated by the Small method with reference to “Introduction to Synthetic Resins for Paints”, Kyozo Kitaoka, p23-p31, Kobunshi Shuppankai (1986), Tables 2-8 and 2-9. It is a thing.

That is, the cohesive energy constant F (cal ^1/2 cc ^1/2 / mol) of a specific atom and atomic group given by the method of small, the density is s (g / cc), the basic molecular weight is M, and δ = Let the value calculated by (sΣF) / M be the solubility parameter δ. In the present invention, the value of small is used as the cohesive energy F.

(1) Monomer solubility parameter
As an example, a calculation example of methyl methacrylate (density 0.944 g / cc) is shown.

  F of each component constituting methyl methacrylate is

It becomes. Therefore, the solubility parameter δm of methyl methacrylate is
δm = 0.944 × 947 ÷ 100 = 8.94
It becomes.

  Typical monomer solubility parameters determined by this calculation method are:

It is.

(2) Solubility parameter δp of carboxyl group-containing acrylic copolymer (A)
In the present invention, the solubility parameter δp of the carboxyl group-containing acrylic copolymer (A) was calculated according to the following formula. That is, it is calculated by the following formula from the molar fraction Xi (%) of each monomer in the carboxyl group-containing acrylic copolymer (A) and the solubility parameter δi of each monomer.

δp = Σ (δi × Xi / 100)
Therefore, in order to bring the solubility parameter δp of the carboxyl group-containing acrylic copolymer (A) into the above range, the composition may be adjusted in consideration of the solubility parameter of the monomer used.

(3) Solubility parameter δs of organic solvent (B)
The solubility parameter δs of the organic solvent (B) is determined in the same manner as the method for calculating the solubility parameter δp of the carboxyl group-containing acrylic copolymer (A). Examples of n-heptane are shown below.

δs = 0.676 × 1093 ÷ 100 = 7.39
In addition, the solubility parameter δs when the organic solvent (B) is a mixture of two or more types is calculated from the following formula based on the molar fraction Xi (%) of each solvent component in the mixed organic solvent and the solubility parameter δi of each solvent component. Is calculated by

δp = Σ (δi × Xi / 100)
In the present invention, when copolymerizing the carboxyl group-containing acrylic monomer, the absolute value of the difference between the solubility parameter of the carboxyl group-containing acrylic copolymer (A) and the solubility parameter of the organic solvent (B) (ΔSP ) Is preferably selected so that the copolymer composition and solvent type are 1.0 or more. The polymerization is more preferably 1.1 or more, and in particular, the polymerization is carried out under the condition of 1.2 or more so that there is no adhesion to the wall of the polymerization tank during the polymerization, and the produced copolymer can be easily taken out as a powder. Is preferable. Further, by designing the polymerization conditions such that the above ΔSP is in the range of 1.0 to 1.9, more preferably in the range of 1.2 to 1.8, and even more preferably in the range of 1.5 to 1.7. , To perform precise control that does not cause a large shift between the composition of the charged monomer mixture before the start of polymerization and the copolymer composition of the copolymer to be generated, and to control molecular weight with a narrower molecular weight distribution and higher uniformity It is more desirable in that it can.

  In the granulation step (II) in the production method of the present invention, an organic solvent slurry (hereinafter referred to as co-polymerization) containing the carboxyl group-containing acrylic copolymer (A) polymerized with a specific polymerization solvent obtained in the polymerization step (I). Fine particles in the coalesced (A) slurry) are granulated. That is, after adding the solvent (C) to the copolymer (A) slurry obtained in the polymerization step (I), the mixture is stirred at a temperature of 50 to 120 ° C., and then solid-liquid separated. By passing through such a granulation step (II), the fine particles of the copolymer (A) can be granulated into particles having a good handleability.

  In the present invention, the solvent (C) is at least one selected from aliphatic hydrocarbons, carboxylic acid esters, ketones, and water. As the aliphatic hydrocarbon, carboxylic acid ester, and ketone, a solvent that can be used in the organic solvent (B) described above can be used. In particular, a solvent having a solubility parameter (δm) higher than the solubility parameter (δm) of the organic solvent (B) is preferable, and for example, a carboxylic acid ester and water are preferable. For example, the organic solvent (B) is preferably a mixture of a carboxylic acid ester and an aliphatic hydrocarbon, and the solvent (C) is preferably a carboxylic acid ester or water.

  Moreover, it is preferable that the addition amount of a solvent (C) is 0.01 to 10 weight% of an organic solvent (B). If it is less than 0.01% by mass, sufficient effects may not be obtained. Moreover, the effect of sufficient granulation is acquired by addition of 10 mass%.

  In this invention, after addition of a solvent (C), it stirs in 50-120 degreeC, Preferably it is 60-110 degreeC, More preferably, it is 70-100 degreeC. When the temperature is less than 50 ° C., the aggregation of the particles is insufficient, so that the resulting copolymer (A) is in a fine powder form and tends to be inferior in handling properties. Moreover, when exceeding 120 degreeC, since copolymer particle | grains will coalesce and it will become a lump shape, it will become difficult to take out as particle | grains and the objective of this invention cannot be achieved in any case.

  The apparatus for performing the granulation operation is not particularly limited as long as the temperature can be controlled within the above range, and an autoclave or the like equipped with a normal stirrer can be used. In the granulation operation, the copolymer (A) slurry and / or the solvent (B) can be preheated.

  In this invention, although the temperature in the case of filtration after heating stirring is not specifically limited, Preferably it is 30-50 degreeC, More preferably, it carries out in the range of 35-45 degreeC. When the temperature is lower than 30 ° C., the particles are likely to be in a gel state and may not be obtained as particles having good handling properties. If the temperature exceeds 50 ° C., the particles may coalesce and may not be obtained as particles with good handling properties.

  The solid-liquid separation method after the heating and stirring is not particularly limited as long as filtration is possible, and a normal centrifugal separator, a pressure filter, a suction filter, a belt filter, or the like is preferably used. it can.

  Further, if necessary, the carboxyl group-containing acrylic copolymer (A) cake containing the organic solvent (B) and the solvent (C) obtained by the above-described solid-liquid separation operation is subjected to a shelf dryer, a conical dryer, a centrifuge. It is also possible to produce a carboxyl group-containing acrylic copolymer (A) that does not contain an organic solvent (B) by drying with a formula dryer or the like.

  The number average particle size of the carboxyl group-containing acrylic copolymer (A) produced in the present invention thus obtained is 150 μm or more and 50,000 μm or less, and in a preferred embodiment, the number average particle size is 150 μm or more and 10 In a more preferred embodiment, the number average particle size is 250 μm or more and 10,000 μm or less. The carboxyl group-containing acrylic copolymer (A) particles having a number average particle diameter in the above range tend to be excellent in handling properties. In addition, the number average particle diameter mentioned here represents the number average particle diameter calculated by observing with a scanning electron microscope (SEM) at 150 times or 10,000 times and analyzing the primary particle diameter.

  The carboxyl group-containing acrylic copolymer (A) obtained in the present invention has a weight average molecular weight (hereinafter also referred to as Mw) in the range of 2,000 to 1,000,000 in the production method of the preferred embodiment. In a more preferred embodiment, it is possible to obtain those in the range of 5,000 to 500,000. When Mw is less than 2,000, the carboxyl group-containing acrylic copolymer (A) may not be precipitated or precipitated as a dispersoid in the organic solvent (B) and may not meet the purpose of the present invention. . In addition, the polymer is brittle and the mechanical properties tend to be poor. When Mw exceeds 1,000,000, high-molecular weight substances that are not sufficiently melted or dissolved in melt-molded or solution-coated products tend to remain as foreign matters, and fisheye and repellency defects are likely to occur. Tend to be. In addition, the weight average molecular weight as used in the field of this invention shows the weight average molecular weight in the absolute molecular weight measured by the multi-angle light scattering gel permeation chromatograph (GPC-MALLS). As described above, the method for controlling the molecular weight of the carboxyl-containing acrylic copolymer (A) of the present invention within the above-mentioned preferable range includes alkyl mercaptan, carbon tetrachloride, carbon tetrabromide, dimethylacetamide, dimethylformamide, triethylamine and the like. A method of adding a chain transfer agent can be preferably used. Among these chain transfer agents, alkyl mercaptans can be preferably used. Further, examples of alkyl mercaptans include n-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-tetradecyl mercaptan, and n-octadecyl mercaptan. Etc. In the most preferred embodiment, t-dodecyl mercaptan and n-dodecyl mercaptan are used. The amount of the alkyl mercaptan added is preferably 0.2 to 5.0 parts by weight, more preferably 0.3 to 4 parts by weight based on 100 parts by weight of the total amount of the monomer mixture in order to control the molecular weight to a preferable level. 0.0 part by weight, more preferably 0.4 to 3.0 parts by weight.

  In the present invention, a carboxyl group-containing acrylic copolymer having a homogeneous molecular weight distribution can be obtained by selecting a specific copolymer composition and solvent type. According to the manufacturing method of the said preferable aspect, the molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of a carboxyl group-containing acrylic copolymer (A) is obtained in the range of 1.5-5.0. In a more preferred embodiment, those in the range of 1.7 to 4.0 can be obtained, and in a particularly preferred embodiment, those in the range of 2.0 to 3.5 are obtained. It is possible. The carboxyl group-containing acrylic copolymer (A) having such a molecular weight distribution tends to be excellent in molding processability and can be preferably used.

  In the present invention, the carboxyl group-containing acrylic copolymer (A) is represented by (i) a carboxyl group-containing acrylic unit represented by the following general formula (1) and (ii) represented by the following general formula (2). In the case of the copolymer (A) containing an acrylic monomer unit, the copolymer (A) is subsequently heated in the presence or absence of a suitable catalyst (a) dehydration and / or Or (b) a glutaric anhydride unit-containing thermoplastic copolymer (D) that is excellent in colorless transparency and thermal stability by passing through a step (second step) of carrying out an intramolecular cyclization reaction by dealcoholization. It has been found that it is possible to produce.

(In the above formula, R ¹ is the same or different and represents any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms)

(However, R ² represents any one selected from hydrogen and an alkyl group having 1 to 5 carbon atoms, and R ³ is unsubstituted or substituted with a hydroxyl group or halogen with a C 1-6 aliphatic hydrocarbon group and carbon number. Any one selected from 3 to 6 alicyclic hydrocarbon groups).

  The (i) carboxyl group-containing acrylic unit represented by the general formula (1) is obtained by copolymerizing a carboxyl group-containing acrylic monomer represented by the following general formula (4).

(In the above formula, R ⁶ is the same or different and represents any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms).
The acrylic monomer unit represented by (2) can be obtained by copolymerizing an acrylic monomer represented by the following general formula (5).

(Wherein R ⁷ represents any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms, and R 8 is an unsubstituted or substituted C 1-6 aliphatic hydrocarbon group and carbon atom substituted with a hydroxyl group or halogen. Any one selected from alicyclic hydrocarbon groups of formula 3-6 is shown).
The glutaric anhydride unit-containing thermoplastic copolymer (C) in the present invention is (iii) a glutaric anhydride unit represented by the following general formula (3) and (ii) a general formula (2). These are thermoplastic copolymers containing acrylic monomer units, and these can be used alone or in combination of two or more.

(In the above formula, R ⁴ and R ⁵ are the same or different and represent any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms)
In this case, typically, by heating the copolymer (A), the carboxyl groups of the two units (i) carboxyl group-containing acrylic monomer units are dehydrated, or adjacent (i) carboxyl groups. One unit of the glutaric anhydride unit is produced by elimination of alcohol from the acrylic monomer unit and (ii) the acrylic monomer unit.

  The thermoplastic copolymer (D) containing glutaric anhydride units produced according to the present invention makes use of its excellent heat resistance, colorless transparency and retention stability, and is used for electrical / electronic parts, automobile parts, mechanical mechanism parts. It can be used for various applications such as housings for OA equipment, home appliances, etc., their parts, and general goods.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Each measurement and evaluation was performed by the following method.

(1) Weight average molecular weight / molecular weight distribution The obtained copolymer was dissolved in tetrahydrofuran to prepare a measurement sample. Gel permeation chromatograph equipped with a DAWN-DSP type multi-angle light scattering photometer (manufactured by Wyatt Technology) using tetrahydrofuran as a solvent (pump: model 515, manufactured by Waters, column: TSK-gel-GMHXL, manufactured by Tosoh Corporation) ) Was used to measure the weight average molecular weight (absolute molecular weight) and the number average molecular weight (absolute molecular weight). The molecular weight distribution was calculated by weight average molecular weight (absolute molecular weight) / number average molecular weight (absolute molecular weight).

(2) Composition of each component In heavy dimethyl sulfoxide, ¹ H-NMR was measured at 30 ° C. to determine the composition of each copolymer unit.

(3) Solubility parameter difference (ΔSP value)
“Introduction to Synthetic Resins for Paints”, Kyozo Kitaoka, p23-p31, Kobunshi Kyokukai (1986), Tables 2-8 and 2-9, with the method of Small (a), (b ), The solubility parameter δp of the copolymer and the solubility parameter δs of the organic solvent were calculated, and the absolute value of the difference was determined as the difference in solubility parameter.

(A) Copolymer solubility parameter δp
From the molar fraction Xi of each monomer unit in the copolymer and the solubility parameter δi of each monomer, the calculation was performed according to the following formula.

δp = Σ (δi × Xi / 100)
(B) Solubility parameter δs of organic solvent
The calculation was performed in the same manner as the calculation method of the solubility parameter δp of the copolymer. In addition, the solubility parameter δs when the organic solvent is a mixture of two or more types was calculated by the following formula from the molar fraction Xi (%) of each solvent component in the mixed organic solvent and the solubility parameter δi of each solvent component. .

δp = Σ (δi × Xi / 100)
(4) Number average particle diameter The obtained copolymer cake was observed at 150 times or 10,000 times using a scanning electron microscope (hereinafter also referred to as SEM), and the primary particle diameter was analyzed (image used: Scion). The image analysis software “Scion Image” manufactured by Corporation was calculated.

Example 1
(A) Polymerization step:
A mixed material of the following (a) is supplied to a stainless steel autoclave having a capacity of 20 liters and equipped with a baffle and a foudra-type stirring blade, dissolved while stirring at 250 rpm, and the system is filled with nitrogen gas at 10 L / min. Bubbled for 15 minutes. Next, nitrogen gas was flowed at a flow rate of 5 L / min, and the temperature was raised to 95 ° C. while stirring the reaction system. The following mixed substances (b) were sequentially added over 40 minutes, and after maintaining for another 60 minutes, the polymerization was terminated to obtain a copolymer slurry (a). From the initial stage of the polymerization, the copolymer was dispersed in a slurry as a dispersoid, and the polymerization proceeded well without any adhesion to the wall of the polymerization tank.

Mixed substance (I):
20 parts by weight of methacrylic acid,
80 parts by weight of methyl methacrylate,
175 parts by weight of n-heptane,
525 parts by weight of butyl acetate,
Mixed substances (b):
25 parts by weight of n-heptane,
75 parts by weight of butyl acetate,
Lauryl peroxide 0.8 parts by weight.

  A small amount of the resulting slurry was added to the qualitative filter paper No. And suction filtration using No. 1, followed by drying at 80 ° C. for 12 hours to obtain a powdery copolymer cake (a ′). Mw was 120,000, and molecular weight distribution (Mw / Mn) was 3.03. The copolymer composition is MMA / MAA (weight ratio) = 72/28, and the absolute value ΔSP of the solubility parameter difference between the copolymer (A) (δp = 9.20) and the organic solvent (B) is 1. 65. The average particle size was 5.0 μm (calculated at 10,000 times).

(B) Granulation step:
1 part by weight of butyl acetate was added to the reaction solution after polymerization, the temperature was raised to 80 ° C. while stirring, and the temperature was maintained for 60 minutes, and then the heating and stirring was terminated to obtain a copolymer slurry.

  A small amount of the resulting slurry was added to the qualitative filter paper No. 1 was subjected to suction filtration and dried at 80 ° C. for 12 hours to obtain a copolymer cake of Example 1. The average particle size was 350 μm (calculated at 150 times).

Example 2:
In the granulation step, a copolymer cake of Example 2 was obtained in the same manner as in Example 1 except that the amount of butyl acetate added was changed from 1 part by weight to 10 parts by weight. The average particle size was 410 μm (calculated at 150 times).

Example 3:
In the granulation step, a copolymer cake of Example 3 was obtained in the same manner as in Example 1 except that the amount of butyl acetate added was changed from 1 part by weight to 50 parts by weight. The average particle size was 480 μm (calculated at 150 times).

Example 4:
In the granulation step, a copolymer cake of Example 4 was obtained in the same manner as in Example 2 except that the solvent to be added was changed from butyl acetate to water. The average particle size was 570 μm (calculated at 150 times).

Comparative Example 1:
A copolymer cake of Comparative Example 1 was obtained in the same manner as in Example 1 except that no solvent was added. The average particle size was 10 μm (calculated at 10,000 times).

Comparative Example 2:
In the polymerization step, the polymer substance of Comparative Example 2 was obtained in the same manner as in Example 1 except that the mixed substance (I) was changed to the following mixed substance (C) and the granulation process was not performed. The average particle size was 5.5 μm (calculated at 10,000 times).

Mixed substances (C):
20 parts by weight of methacrylic acid,
80 parts by weight of methyl methacrylate,
175 parts by weight of n-heptane,
535 parts by weight of butyl acetate,
From comparison between Examples 1 to 4 and Comparative Examples 1 and 2, it can be seen that particles can be granulated by adding a specific solvent to the slurry after polymerization and heating and stirring at a specific temperature.

  The polymerization rally obtained in Example 1 was transferred to a pressure filter and subjected to solid-liquid separation (second filtration), and further dried at 80 ° C. for 12 hours to obtain a polymer cake.

  Into 100 parts by weight of the copolymer cake, 0.2 parts by weight of lithium acetate as a catalyst was blended, and 38 mmφ biaxial / uniaxial composite continuous kneading extruder (HTM38 (manufactured by CTE, L / D = 47. 5. Vent part: 2 places) While purging nitrogen from the hopper part at an amount of 10 L / min, intramolecular cyclization reaction was performed at a screw rotation speed of 75 rpm, a raw material supply rate of 10 kg / h, and a cylinder temperature of 290 ° C. In this way, a pellet-like glutaric anhydride-containing thermoplastic copolymer was obtained, which had excellent heat resistance and thermal stability with a small amount of generated gas even during residence, and was particularly excellent in colorless transparency. A glutaric anhydride-containing thermoplastic copolymer could be produced.

Claims (10)

(I) copolymerizing a monomer mixture containing a carboxyl group-containing acrylic monomer and other acrylic monomers copolymerizable therewith, and (i) containing a carboxyl group-containing acrylic monomer unit A method for producing a copolymer, which comprises the following polymerization step (I) and granulation step (II) when producing the copolymer (A).
(I) Polymerization Step An organic solvent containing no aromatic group, the monomer mixture containing a carboxyl group-containing acrylic monomer and other acrylic monomers copolymerizable therewith is dissolved, and (I) Polymerization step (II) in which a copolymer slurry containing a carboxyl group-containing acrylic monomer unit is copolymerized in an organic solvent (B) having a solubility of 1 g / 100 g or less to obtain a copolymer slurry. Granulation step The solvent (C) is added to the copolymer slurry solution and stirred at a temperature of 50 to 120 ° C, followed by solid-liquid separation to obtain a copolymer (A).   The method for producing a copolymer according to claim 1, wherein the amount of the solvent (C) added is 0.01 to 10% by weight of the organic solvent (B).   The method for producing a copolymer according to claim 1 or 2, wherein the organic solvent (B) is at least one selected from aliphatic hydrocarbons, carboxylic acid esters, and ketones.   The method for producing a copolymer according to any one of claims 1 to 3, wherein the organic solvent (B) is a mixture of an aliphatic hydrocarbon and a carboxylic acid ester.   The method for producing a copolymer according to claim 4, wherein the organic solvent (B) is a mixture of an aliphatic hydrocarbon and a carboxylic acid ester, and the weight ratio thereof is 5/95 to 70/30. . The method for producing a copolymer according to any one of claims 1 to 5, wherein the solvent (C) is a carboxylic acid ester and / or water.
  The polymerization step (I) is performed under the condition that the absolute value (ΔSP) of the difference between the solubility parameter of the copolymer (A) and the solubility parameter of the organic solvent (B) is 1.0 or more. The method for producing a copolymer according to claim 1. The copolymer (A) is (i) a carboxyl group-containing acrylic monomer unit represented by the following general formula (1) and (ii) an acrylic monomer unit represented by the following general formula (2) The method for producing a copolymer according to claim 1, wherein the copolymer is a copolymer containing

(However, R ¹ is the same or different and represents any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms.)

(However, R ² represents any one selected from hydrogen and an alkyl group having 1 to 5 carbon atoms, and R ³ is an unsubstituted or substituted C 1-6 aliphatic hydrocarbon group and carbon having a hydroxyl group or halogen. Any one selected from alicyclic hydrocarbon groups of 3 to 6)   The copolymer according to claim 8, wherein the copolymer (A) contains (i) 15 to 50% by weight of a carboxyl group-containing acrylic monomer unit represented by the general formula (1). Method. A copolymer (A) is produced by the method for producing a copolymer according to claim 8 or 9 (first step), and subsequently, the copolymer (A) is subjected to heat treatment, and (a) dehydration and And / or (b) a step (second step) in which intramolecular cyclization is performed by dealcoholization reaction, (iii) a glutaric anhydride unit represented by the following general formula (3) and (ii) an unsaturated carboxylic acid A method for producing a thermoplastic copolymer containing glutaric anhydride units, which comprises producing a thermoplastic copolymer (D) containing an alkyl ester unit.

(However, R ⁴ and R ⁵ are the same or different and represent any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms.)