JP2009073931A - Method for manufacturing resin granular powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin granular powder having a particle diameter of 1 mm or less in a manufacturing method for the resin granular powder for performing particulation while efficiently removing a solvent. <P>SOLUTION: The above object can be accomplished by the manufacturing method for the resin granular powder characterized in that the resin granular powder is obtained by step (1) for removing the solvent from a solution containing an isobutylene-based polymer by heating while a water-soluble polymer and water are added to the solution and liquid-liquid dispersion is performed by stirring. As the water-soluble polymer, polyvinyl alcohol, methylcellulose or the like is preferably used. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

    The present invention relates to a method for producing a resin granule that is granulated while efficiently removing a solvent, and more particularly, to a method for producing a resin granule comprising a styrene block copolymer.

    Isobutylene block comprising a polymer block mainly composed of isobutylene and a polymer block mainly composed of aromatic vinyl monomer by cationic polymerization of isobutylene and aromatic vinyl monomer such as styrene. Regarding the method for producing the copolymer, for example, US Pat. No. 4,946,899 (Patent Document 1) discloses a production method in a mixed solvent in which methyl chloride and methylcyclohexane are combined.

    Japanese Patent Publication No. 7-59601 (Patent Document 2) also discloses a process for producing an isobutylene block copolymer comprising an isobutylene polymer block and a styrene polymer block in a mixed solvent comprising methylene chloride and hexane. ing.

    Generally, as a method for recovering a rubber-like polymer, there are many cases in which a method of pelletizing by an underwater cutting method after removing a solvent by a thin film evaporator or an extruder or a method of granulating by steam stripping is adopted.

    As a method for producing a granular material by steam stripping, a method of injecting a polymer solution into hot water containing a dispersant and volatilizing and recovering the solvent is generally used. Examples thereof include acid salts (Patent Document 3) and nonionic surfactants having a cloud point equal to or higher than the solvent removal temperature (Patent Document 4).

    However, the isobutylene block copolymer is an elastomer having the characteristics that the resin has high adhesiveness and low hardness, and therefore requires a device to prevent fusion of the resin during the hot water treatment. In addition, it was difficult to obtain particles having an average particle size of 1 mm or less even with a nonionic surfactant with less foaming.

In this way, it is hoped that development of a manufacturing process that stably produces granular products will be solved by solving various problems in the production of spherical resin particles having an average particle size of 1 mm or less from isobutylene block copolymers. It was rare.
U.S. Pat. No. 4,946,899 Japanese Patent Publication No. 7-59601 JP 49-53991 A JP 2004-155880 A

    In view of the above situation, the present invention provides a method capable of stably producing an isobutylene-based polymer excellent in blocking properties without deterioration in quality, particularly an isobutylene-based block copolymer resin powder. It is the purpose.

  The present invention is a method for producing a resin granule by removing a solvent from a polymer solution, and after adding a water-soluble polymer and water to a solution containing the polymer, liquid-liquid dispersion is performed by stirring. It is related with the manufacturing method of a resin granular material characterized by obtaining a resin granular material by the process (1) which removes a solvent by heating. In addition, the process (1) of this invention means the process of removing a solvent by heating, carrying out liquid-liquid dispersion by stirring.

    In a preferred embodiment, the water-soluble polymer is polyvinyl alcohol, methyl cellulose, or a mixture thereof.

    As a preferred embodiment, the present invention relates to a production method characterized in that the solvent removal temperature in step (1) is 70 ° C. or higher and lower than 130 ° C.

    As a preferred embodiment, the present invention relates to a production method characterized in that the polymer has a block mainly composed of an aromatic vinyl monomer.

    In a preferred embodiment, the polymer is an isobutylene polymer obtained by polymerizing a monomer component containing at least one aromatic vinyl monomer and an isobutylene monomer. It relates to a manufacturing method.

    In a preferred embodiment, the polymer is a block copolymer comprising (A) a polymer block mainly composed of isobutylene and (B) a polymer block mainly composed of an aromatic vinyl monomer. The present invention relates to a production method characterized by being a polymer.

    In a preferred embodiment, the solvent of the isobutylene polymer solution is a mixed solvent of a primary and / or secondary monohalogenated hydrocarbon having 3 to 8 carbon atoms and an aliphatic and / or aromatic hydrocarbon. The present invention relates to a manufacturing method.

    According to the present invention, the blocking property after drying of the resin particles obtained by removing the solvent from the isobutylene polymer can be improved without quality deterioration.

    The polymer of the present invention is not particularly limited as long as it is a polymer obtained by solution polymerization, but (A) a polymer block mainly composed of isobutylene, and (B) an aromatic vinyl monomer. An isobutylene copolymer comprising a polymer block constituted as follows is preferred. Specifically, a monomer such as isobutylene and an aromatic vinyl monomer is cationically polymerized with an initiator in the presence of a Lewis acid catalyst. Can be suitably used.

    The polymer block composed mainly of isobutylene in (A) is usually a polymer block containing 60% by weight or more, preferably 80% by weight or more of isobutylene units. The polymer block mainly composed of the aromatic vinyl monomer (B) is usually a polymer containing 60% by weight or more, preferably 80% by weight or more of an aromatic vinyl monomer unit. It is a block.

    The aromatic vinyl monomer is not particularly limited, and examples thereof include styrene, o-, m- or p-methylstyrene, α-methylstyrene, and indene. These may be used alone or in combination of two or more. Of these, styrene, p-methylstyrene, α-methylstyrene or a mixture thereof is particularly preferable from the viewpoint of cost.

The Lewis acid catalyst in the present invention is not particularly limited as long as it can be used for cationic polymerization, and examples thereof include metal halides such as TiCl ₄ , BCl ₃ , BF ₃ , AlCl ₃ , SnCl ₄ , among others. Titanium tetrachloride (TiCl ₄ ) is preferred.

    The polymerization solvent used in the cationic polymerization is not particularly limited, and a solvent composed of a halogenated hydrocarbon, a non-halogen solvent, or a mixture thereof can be used. Preferably, it is a mixed solvent of primary and / or secondary monohalogenated hydrocarbons having 3 to 8 carbon atoms and aliphatic and / or aromatic hydrocarbons.

    The primary and / or secondary monohalogenated hydrocarbon having 3 to 8 carbon atoms is not particularly limited, and examples thereof include methyl chloride, methylene chloride, 1-chlorobutane and chlorobenzene. Among these, 1-chlorobutane is preferable from the standpoint of the solubility of the isobutylene block copolymer, the ease of detoxification by decomposition, the cost, and the like.

    The aliphatic and / or aromatic hydrocarbons are not particularly limited, and examples thereof include pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane, ethylcyclohexane, and toluene. One or more selected from the group consisting of methylcyclohexane, ethylcyclohexane and toluene are particularly preferred.

    In addition, as an initiator used in cationic polymerization, it is preferable to use a compound represented by the following formula (I).

(CR ¹ R ² X) _n R ³ (I)
[Wherein, X represents a halogen atom, an alkoxy group having 1 to 6 carbon atoms or an acyloxy group. R ¹ and R ² are the same or different and each represents a monovalent hydrocarbon group hydrogen atom or 1 to 6 carbon atoms, R ¹ and R ² may be different even in the same. R ³ represents a polyvalent aromatic hydrocarbon group or a polyvalent aliphatic hydrocarbon group. n shows the natural number of 1-6. ]
Specific examples of the compound of the general formula (I) include 1,4-bis (α-chloro-isopropyl) benzene [C ₆ H ₄ (C (CH ₃ ) ₂ Cl) ₂ ]. , 4-bis (α-chloro-isopropyl) benzene is also called dicumyl chloride].

    In the polymerization of the isobutylene block copolymer, an electron donor component can be further present if necessary. Examples of such compounds include pyridines, amines, amides, sulfoxides, esters, or metal compounds having an oxygen atom bonded to a metal atom.

    In carrying out the actual polymerization, each component is mixed at a temperature of, for example, −100 ° C. or more and less than 0 ° C. under cooling. In order to balance the energy cost and the stability of the polymerization, a particularly preferred temperature range is −80 ° C. to −30 ° C.

    The number average molecular weight of the isobutylene block copolymer is not particularly limited, but is preferably 30,000 to 500,000, particularly preferably 50,000 to 400,000 from the viewpoint of fluidity, workability, physical properties, and the like.

    After the polymerization, the polymer solution containing the isobutylene block copolymer is brought into contact with water or alkaline water to deactivate the catalyst to stop the reaction, followed by washing with water to remove catalyst residues and metal ions. Can be extracted and removed to obtain a purified dope.

    The deactivation and water washing temperatures are not particularly limited, but are preferably in the range of room temperature to 100 ° C. Moreover, the amount of water used for deactivation and washing is not particularly limited, but the volume ratio of water to the polymer solution is preferably in the range of 1/10 to 10.

    The purified polymer solution thus obtained is subsequently subjected to the granulation step (1) (also referred to as a crumbization step). As for the resin concentration in the polymer solution, it is desirable that the solvent used for the polymerization is added if necessary to make it 10 to 60% by weight to form granules. When the dope concentration is low, the concentration can be adjusted to a desired concentration by using one or a plurality of evaporators such as flash evaporation, thin film evaporation, stirring tank, and wet wall type. Moreover, when the polymer solution concentration is high, it can be adjusted to a desired concentration by diluting with a solvent.

    A water-soluble polymer (such as polyvinyl alcohol) and water are added to the purified polymer solution thus obtained, that is, the solution after completion of the polymerization containing the isobutylene block copolymer from which the catalyst has been deactivated and removed. The resin powder can be obtained by the step (1) in which the solvent is removed by heating while being liquid-liquid dispersed by stirring. The amount of water to be added is not particularly limited, but it is preferably added in a volume of 0.5 to 4 times the polymer solution from the viewpoint of ease of liquid-liquid dispersion.

    The water-soluble polymer is not particularly limited as long as it has an emulsifying action, a protective colloid action, and a dispersing action. For example, gum arabic, carrageenan, guar gum, locust bean gum, pectin, tragacanth, corn starch (corn starch), Polysaccharides such as xanthan gum and dextrin, proteins such as gelatin, casein and sodium chondroitin sulfate, celluloses such as ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, nitrocellulose and cationized cellulose, phosphorylated starch, etc. Starches, sodium alginate, alginic acids such as propylene glycol alginate, sodium polyacrylate, polycarbonate vinyl Acrylic acids such as mer, polyacrylamide, acrylamide / acrylate copolymer, vinyl polymers such as polyvinyl pyrrolidone, polyvinyl alcohol, PVP / VA (polyvinyl pyrrolidone / vinyl acetate) copolymer, other polyethylene glycols, cations Guar gum, sodium hyaluronate and the like. These may be used singly or in combination of two or more. Of these, methyl cellulose and polyvinyl alcohol are preferable from the viewpoint of cost. The amount of the water-soluble polymer to be added is not particularly limited, but is preferably 0.05 to 5 parts by weight with respect to the polymer. If it is 0.05 parts by weight or less, the properties as a dispersant cannot be sufficiently exhibited, and particles are not formed. On the other hand, when the amount exceeds 5 parts by weight, the problem of foaming in the deterioration of the physical properties of the polymer and the granulation becomes remarkable.

    Moreover, in order to further improve the blocking property in the step (1), a lubricant can be used in combination. Examples of the lubricant include a lubricant for imparting lubricity to the resin during resin processing, a release agent for facilitating removal of the molded body from a mold, and the like. Specific examples of the lubricant include calcium carbonate, fatty acid amide, fatty acid ester, metal soap, polyolefin, silica, fluororesin, talc and the like. Among these, one kind or two or more kinds may be combined. These may be used before removing the solvent in step (1), or may be used by a method of adding to the granular slurry after removing the solvent. The amount of lubricant to be added is not particularly limited, but is preferably 0 to 5 parts by weight based on the polymer. When the amount exceeds 5 parts by weight, the physical properties of the weight body are significantly deteriorated.

    Examples of calcium carbonate include light calcium carbonate and calcium bicarbonate having an average particle size of 0.5 to 15 microns, and those obtained by treatment with saturated fatty acids or surfactants, or magnesium or silicates. The thing which mix | blended etc. can be mentioned.

    Examples of fatty acid amides include stearic acid amide, ethylene bis stearic acid amide, erucic acid amide, ethylene biserucic acid amide, oleic acid amide, ethylene bisoleic acid amide, behenic acid amide, ethylene bislauric acid amide, etc. Can do.

    Examples of fatty acid esters include methyl laurate, methyl myristate, methyl palmitate, methyl stearate, methyl oleate, methyl erucate, methyl behenate, butyl laurate, butyl stearate, isopropyl myristate, isopropyl palmitate Octyl palmitate, octyl stearate and the like.

    Examples of the metal soap include metal soaps using potassium, sodium, aluminum, calcium, zinc, magnesium, barium and the like.

    Examples of polyolefins include powdered polyolefins such as polyethylene, polypropylene, polymethylpentene, and polybutene. At least one selected from these is used. Among these, polypropylene powder can be preferably used.

    Examples of silica include powdery dry silica and wet silica. Among these, hydrophobic anhydrous amorphous silica obtained by reacting the hydroxyl group on the silica surface with monomethyltrichlorosilane or dimethyldichlorosilane is preferable.

    Examples of fluororesins include polytetrafluoroethylene (hereinafter referred to as PTFE), ethylene / tetrafluoroethylene copolymer, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / hexafluoropropylene / Examples thereof include a vinylidene fluoride copolymer, a tetrafluoroethylene / hexafluoropropylene / perfluoroalkyl vinyl ether copolymer, and polymonochlorotrifluoroethylene. At least one selected from these is used. Among these, PTFE powder is preferably used.

    In the present invention, the polymer solution and water are liquid-liquid dispersed in the presence of polyvinyl alcohol, and then the step (1) in which the solvent is removed by heating, powders are formed satisfactorily. As a device used for liquid-liquid dispersion by stirring and solvent removal, a container equipped with a stirrer is preferably used. The shape of the stirring blade is not particularly limited, and any blade such as a screw blade, a propeller blade, an anchor blade, a paddle blade, an inclined paddle blade, a turbine blade, and a large lattice blade can be used. In these, liquid-liquid dispersion operation and solvent removal operation can be performed using the same stirring tank, or after the liquid-liquid dispersion operation is performed in advance to form a dispersion liquid, the solvent removal is continuously performed for a plurality of stirring operations. It can also be performed using a tank.

    Although the liquid temperature of a process (1) is not specifically limited, It is preferable that it is more than the azeotropic point of a solvent and water. However, even if it is less than the azeotropic point, the solvent can be easily removed by reducing the pressure in the container. Specifically, it is preferably 70 ° C. or higher and lower than 130 ° C., more preferably 80 ° C. or higher and lower than 110 ° C. When it is 70 ° C. or lower, the solvent removal rate is lowered, which is not preferable in terms of production efficiency. On the other hand, when the temperature is 130 ° C. or higher, the function of the nonionic surfactant is lost and a stable liquid-liquid dispersion cannot be formed.

    The aqueous solution containing the obtained resin granular material can further remove the remaining solvent by passing through the process (2) by the steam stripping operation which continues aeration of steam. The vessel used for steam stripping only needs to be connected to a pipe for introducing steam, and a method of introducing steam into the stirring vessel is preferably used as in the suspension and solvent removal operations. Further, the steam stripping operation can be carried out by venting steam in the same tank following the solvent removal, or can be carried out continuously by providing a separate stripping tank. In addition, as a continuous method, stripping can be performed by connecting one or more aeration and stirring tanks or by bringing steam and resin slurry in contact with each other in a shelf system.

    The aqueous solution containing the resin particles after the steam stripping is dehydrated and dried by the step (3) described below. In order to recover the resin particles from the aqueous solution containing the resin particles, a dehydration operation using various filters, centrifuges, or the like can be used. The moisture content of the resin powder after dehydration by this operation is not particularly limited, but it is effective in terms of energy efficiency in drying or pelletization to be 10 to 50% by weight.

    The obtained water-containing resin granules are dried to produce product granules by using a conductive heat transfer dryer such as a grooved stir dryer or a hot air receiving dryer such as a fluid dryer. Can do. Although the water content in the product granule is not particularly limited, it is preferably less than 1%.

    Moreover, the water-containing resin granular material after dehydration mentioned above or the product granular material after drying can be commercialized as a resin pellet using an extruder having a devolatilization mechanism. As the extruder having a devolatilization mechanism, a single-screw or twin-screw extruder having a vent mechanism can be used. In particular, the twin-screw extruder is preferably used from the viewpoint of solvent removal and monomer removal efficiency. The resin discharged from the extruder can be made into a final product by strand cutting, underwater cutting, hot cutting, or the like.

    As described above, the polymer of the present invention is not particularly limited as long as it is a polymer obtained by solution polymerization, and a conventionally known polymer can be used. Examples of the polymer of the present invention include a block copolymer generally referred to as a styrene-based thermoplastic elastomer and styrene-butadiene rubber (SBR). Styrenic thermoplastic elastomers include styrene-ethylene butylene copolymer-styrene (S-EB-S), styrene-ethylene propylene copolymer-styrene (S-EP-S), styrene-butadiene-styrene (S- B-S), styrene-isoprene-styrene (S-I-S), and styrene-isobutylene-styrene (S-IB-S).

    EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited only to these examples.

    The molecular weight and tensile strength of the block copolymer shown in this example were measured by the following methods.

    Molecular weight: GPC system manufactured by Waters (column: Shodex K-804 (polystyrene gel) manufactured by Showa Denko KK, mobile phase: chloroform). The number average molecular weight is expressed in terms of polystyrene.

    The particle diameter of the obtained resin granules was confirmed visually.

(Production example)
To a 20 L reaction vessel equipped with a stirrer, 1.70 kg of 1-chlorobutane (dried with molecular sieves), 1.92 kg of hexane (dried with molecular sieves), and 2.90 g of p-dic milk chloride were added. After cooling the reaction vessel to −70 ° C., 2.18 g of N, N-dimethylacetamide and 844 g of isobutylene were added. Furthermore, 85 g of titanium tetrachloride was added to initiate polymerization, and the solution was reacted at −70 ° C. for 2 hours while stirring. Next, 408 g of styrene was added to the reaction solution, and the reaction was further continued for 30 minutes to obtain a polymer solution.

    The obtained polymer solution was poured into a large amount of water to stop the reaction. After the reaction was stopped, the polymer solution phase and the aqueous phase were separated with a separatory funnel. The polymer solution phase was washed twice with the same method, and after confirming that the aqueous layer was neutral, the polymer solution phase was discharged to obtain a polymer solution.

    When GPC analysis was performed, the number average molecular weight was 100,000 and the molecular weight distribution was 1.14.

Example 1
As shown in FIG. 1, 12.5 liters of pure water and 12.5 liters of the polymer solution obtained in the production example were charged into a pressure-resistant stirring apparatus having a tank volume of 50 liters and an inner diameter of 30 cm, and polyvinyl alcohol (Nippon Synthetic Chemical Industry ( 5.1 g of KH-17) manufactured by the company was added. The stirring blade was heated by introducing steam into the stirring tank while stirring at 400 rpm using a two-stage four-padded paddle with a blade diameter of 15 cm.

    When the stirring tank internal temperature reached 70 ° C., the solvent gas was volatilized and introduced into a capacitor attached to the pressure-resistant stirring device, and the solvent was sequentially recovered. The steam supply was stopped when the temperature inside the stirring tank reached 99 ° C. Stirring was stopped after waiting for internal temperature to fall to 50 degreeC, and the resin slurry produced | generated in the stirring tank was collect | recovered (process (1)). The granular material in the recovered resin slurry was particles having a particle size of about 500 μm. The recovered resin slurry was returned to the stirring tank again, sealed and subjected to steam stripping (step (2)). As the stripping conditions, a method of blowing from the lower part of the stirring tank while maintaining 120 ° C. for 60 minutes was adopted.

    This resin slurry was centrifugally dehydrated and dried in a box dryer at 100 ° C. for 2 hours to obtain resin powder particles.

    As shown in Table 1, the obtained resin granules were true spherical resin granules.

(Example 2)
It implemented like Example 1 except having added methylcellulose (Shin-Etsu Chemical Co., Ltd. product MS-400) instead of polyvinyl alcohol in a process (1).

    As shown in Table 1, the obtained resin particles were true spherical resin particles having a particle size of about 500 μm.

(Comparative Example 1)
It implemented like Example 1 except having added sodium palmitate (made by Wako Pure Chemical Industries Ltd.) instead of polyvinyl alcohol in a process (1).

    As shown in Table 1, foaming during evaporation of the solvent was intense, and no resin particles were obtained.

It is explanatory drawing of the pressure | voltage resistant stirring apparatus which performs the granulation and steam stripping of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure-resistant stirring tank 2 Raw material preparation line 3, 4 Jacket warm water line 5 Capacitor 6 Solvent recovery line 7 Steam blowing line

Claims (7)

    A resin, characterized in that a resin granule is obtained by the step (1) of adding a water-soluble polymer and water to a solution containing a polymer and then removing the solvent by heating while being liquid-liquid dispersed by stirring. A method for producing a granular material.     The method for producing a resin granular material according to claim 1, wherein the water-soluble polymer is polyvinyl alcohol, methyl cellulose, or a mixture thereof.     The method for producing a resin particle according to any one of claims 1 and 2, wherein the solvent removal temperature in the step (1) is 70 ° C or higher and lower than 130 ° C.     The method for producing a resin granular material according to any one of claims 1 to 3, wherein the polymer has a block mainly composed of an aromatic vinyl monomer.     The polymer is an isobutylene polymer obtained by polymerizing a monomer component containing at least one aromatic vinyl monomer and isobutylene monomer. The manufacturing method of the resin granular material of any one of these. The polymer is
(A) a polymer block composed mainly of isobutylene;
(B) a polymer block composed mainly of an aromatic vinyl monomer,
The method for producing a resin particle according to any one of claims 1 to 5, wherein the block is a block copolymer. The solvent of the solution containing the polymer is a mixed solvent of primary and / or secondary monohalogenated hydrocarbons having 3 to 8 carbon atoms and aliphatic and / or aromatic hydrocarbons. 6. The method for producing an isobutylene-based resin particle according to any one of 6 above.

Images