JP2009073917A - Method for producing granular-powder resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stably producing a granular-powder resin excellent in blocking resistance property, especially the granular powder of an isobutylene-based block copolymer without spoiling qualities, especially transparency. <P>SOLUTION: The method comprises: a process of forming a granular-powder resin by adding water to a solution containing a polymer (a) having at least one of aromatic vinyl-based monomers and by heating and agitating the mixture; a process of, adding an aqueous emulsion containing particles of a copolymer (b) comprising an acrylic monomer and an aromatic vinyl-based monomer to the obtained aqueous dispersion containing the granular-powder resin; and a process of, recovering the granular-powder resin from the obtained mixture. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a resin particle, and more particularly to a method for producing a resin particle comprising an isobutylene block copolymer.

  As a method for separating and recovering the resin particles from the resin particle aqueous solution, in general, after removing most of the water using various filters and centrifugal dehydrators, fluid dryers, air dryers, etc. Many methods of evaporating moisture using a dryer are employed.

  When the resin is a rubber-like polymer, the obtained granular material is soft and irregular in shape. Therefore, in the conventional method as described above, a problem of blocking often occurs during recovery. Blocking is a phenomenon in which a granular material is consolidated by an action such as softening of the granular material itself, interaction between the surfaces of the granular material, or contact between the granular materials. Depending on the storage condition (load, filling amount, storage temperature, storage humidity) after filling the granular material into packaging materials such as flexible containers (flexible containers), such blocking may occur, and when blocking occurs, Troubles such as powder particles not being able to be removed from the packaging can occur. Further, when blocking occurs in the granular material handling step, troubles such as loss of quantitativeness at the time of supplying the granular material, clogging of the screen, and inability to transport by air are caused.

  Even when an isobutylene-based block copolymer is used as the resin, the problem relating to product blocking is one of the problems to be solved. In other words, if resin particles consisting of an isobutylene block copolymer are collected without adding any surface modifier, troubles such as clogging in the collection hopper or blocking in the flexible container may occur, resulting in problems such as being unable to be dispensed. There was a case. In addition, there is a problem in that the resin powder slurry is clogged in the process before it is dehydrated and dried, causing trouble.

  On the other hand, even when sufficient blocking resistance is maintained by the use of an additive, there is a risk of impairing the transparency of the isobutylene block copolymer product. That is, there is a demand for a method for improving both the blocking resistance of the granular material and the transparency of the product.

  As a measure for improving the blocking resistance of the granular material, the use of an additive is most commonly performed. For example, in Patent Document 1, the blocking resistance of a synthetic resin powder (rubber composition) is improved by copolymerizing methyl methacrylate and styrene in the presence of 1,3-butylene glycol dimethacrylate as a crosslinking agent. (Example 1). However, the synthetic resin powder of Patent Document 1 is an additive for a vinyl chloride resin, and a transparent vinyl chloride resin molded product (final molded product) is obtained by blending a small amount with a vinyl chloride resin. Therefore, Patent Document 1 has no description regarding the transparency of the synthetic resin powder itself. Further, in this method, even when a copolymer comprising 55% by weight of methyl methacrylate and 45% by weight of styrene produced by a polymerization system containing no crosslinking agent is used as an anti-blocking agent, the blocking resistance is hardly improved. It is shown. Furthermore, when this method is applied to isobutylene-based resin particles, a cross-linking agent is included, and fish eyes and strength may be reduced.

  Patent Document 2 discloses a method using a polystyrene emulsion polymer solution as an anti-blocking agent for isobutylene resins. However, with this method, although blocking resistance is improved, depending on the application, the transparency of the product sheet may not be at the level required by the market.

As described above, an effective additive in the resin granule composed of an isobutylene block copolymer has not yet been found, and satisfying two important characteristics improvements such as blocking resistance and transparency are not satisfied. Have difficulty.
Japanese Patent Laid-Open No. 7-3106 WO2007 / 007837

  In view of the above situation, the present invention provides a method capable of stably producing resin granules having excellent blocking resistance, in particular, isobutylene block copolymer resin granules, without impairing quality, particularly transparency. It is intended to provide.

The present invention includes adding water to a solution containing the polymer (a) containing at least one aromatic vinyl monomer component, and forming resin granules by heating and stirring;
Adding an aqueous emulsion containing particles of a copolymer (b) composed of an acrylic monomer and an aromatic vinyl monomer to the obtained resin particle-containing aqueous dispersion;
And a step of recovering the resin particles from the obtained mixture.

  Preferably, the copolymer (b) comprising an acrylic monomer and an aromatic vinyl monomer is 50 to 70% by weight of an acrylic monomer and 30 to 50% by weight of an aromatic vinyl monomer. It is related with the manufacturing method of the resin granular material characterized by comprising.

  Preferably, the copolymer (b) comprising the acrylic monomer and the aromatic vinyl monomer starts the polymerization of the aromatic vinyl monomer after starting the polymerization of the acrylic monomer. It is related with the manufacturing method of the resin granular material characterized by the above-mentioned.

  Preferably, 50% by weight or more of the portion derived from the acrylic monomer in the copolymer (b) comprising the acrylic monomer and the aromatic vinyl monomer is derived from methyl methacrylate. It is related with the manufacturing method of the resin granular material characterized.

  Preferably, the present invention relates to a method for producing a resin particle, wherein the polymer (a) has a block mainly composed of an aromatic vinyl monomer.

  Preferably, the polymer (a) is an isobutylene polymer obtained from at least one aromatic vinyl monomer and an isobutylene monomer. About.

Preferably, the polymer (a) is
(A) a polymer block composed mainly of isobutylene;
(B) a polymer block composed mainly of an aromatic vinyl monomer;
It is related with the manufacturing method of the resin granular material characterized by the above-mentioned.

  Preferably, the difference in refractive index between the resin particle comprising the polymer (a) and the copolymer (b) comprising an acrylic monomer and an aromatic vinyl monomer is within 0.1. It is related with the manufacturing method of the resin granular material characterized by having.

  Preferably, the average particle diameter of the said copolymer (b) which consists of an acryl-type monomer and an aromatic vinyl-type monomer is 0.1-0.3 micrometer, The manufacture of the resin granular material characterized by the above-mentioned. Regarding the method.

  Preferably, the amount of the particles of the copolymer (b) composed of an acrylic monomer and an aromatic vinyl monomer is 100 parts by weight of the polymer (a) constituting the resin particle. It is related with the manufacturing method of the resin granular material characterized by being 0.01-5 weight part by solid content.

  Preferably, the present invention relates to a method for producing a resin granule, comprising the step of further adding an inorganic salt after adding the aqueous emulsion.

  Preferably, the present invention relates to a method for producing a resin particle, wherein the inorganic salt to be added is sodium sulfate.

  Preferably, the present invention relates to a method for producing a resin particle, wherein the inorganic salt is added so that the ratio of (inorganic salt / water in the aqueous dispersion) is 20 mmol / L or more.

  Preferably, after adding the aqueous emulsion containing particles of the copolymer (b) consisting of an acrylic monomer and an aromatic vinyl monomer to the resin particle-containing aqueous dispersion, The present invention relates to a method for producing a resin granule, characterized by heat-treating a mixture at 70 ° C. or higher and lower than 180 ° C.

  The production method of the present invention can improve both two important characteristics such as blocking resistance and transparency of the resin particles. The production method of the present invention is particularly useful in that it can improve the blocking resistance and transparency of the resin particles of the isobutylene block copolymer.

  The method for producing a resin granular material according to the present invention includes adding water to a solution containing a polymer (a) containing at least one aromatic vinyl monomer component, and then heating and stirring the resin. Including a step of forming (powdering) a granular material. The polymer applicable as the polymer (a) is not particularly limited as long as it is a polymer containing at least one aromatic vinyl monomer component, and the present invention is not limited to cationic polymerization, anionic polymerization, and radical polymerization. The present invention can be applied to polymers obtained by various polymerization methods.

  The aromatic vinyl monomer constituting the polymer (a) 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.

  Examples of the polymer (a) include a block copolymer and a styrene-butadiene rubber (SBR) generally called a styrene thermoplastic elastomer. 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). Specific examples of the polymer (a) include an isobutylene polymer obtained by polymerizing a monomer component containing at least one aromatic vinyl monomer and an isobutylene monomer, a styrene-butadiene rubber ( SBR). In particular, because of its high elasticity, it can be used for isobutylene-based block copolymers in which it is difficult to obtain a powder having a good balance between blocking resistance and transparency by conventional methods.

For example, the isobutylene block copolymer is not particularly limited as long as it is a polymer containing isobutylene, but (A) a polymer block mainly composed of isobutylene, and (B) an aromatic vinyl monomer. An isobutylene copolymer composed of a polymer block composed mainly of is preferred. Specifically, a product obtained by cationic polymerization of a monomer such as isobutylene or an aromatic vinyl monomer together with an initiator in the presence of a Lewis acid catalyst has stable quality such as strength and elongation. This is preferable in that an isobutylene block copolymer can be produced.
The polymer block composed mainly of isobutylene of (A) is usually a polymer containing 60% by weight or more of isobutylene units, preferably 80% by weight or more from the viewpoint of maintaining gas barrier properties peculiar to the isobutylene system. It is a block. In addition, the polymer block composed mainly of the aromatic vinyl monomer (B) usually has an aromatic vinyl monomer unit of 60% by weight or more, strength, elongation, etc. as a styrene elastomer. From the viewpoint of maintaining physical properties, the polymer block is preferably contained in an amount of 80% by weight or more.

The Lewis acid catalyst 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 , and tetrachloride. Titanium (TiCl ₄ ) is preferable from the viewpoint of the reactivity of the isobutylene block copolymer, the ease of catalyst recovery, and the safety of the recovered catalyst.

  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. In view of the solubility of the isobutylene block copolymer, a mixed solvent of a primary and / or secondary monohalogenated hydrocarbon having 3 to 8 carbon atoms and an aliphatic and / or aromatic hydrocarbon should be used. Is preferred.

  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 (butyl chloride), 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. Among these, one or more selected from the group consisting of methylcyclohexane, ethylcyclohexane and toluene are particularly preferable.

  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 solution of the isobutylene block copolymer (a) obtained by polymerizing the monomer component by a predetermined method is brought into contact with water or alkaline water to deactivate the catalyst and stop the reaction, Subsequently, washing with water is performed to extract and remove catalyst residues and metal ions to obtain a purified dope.

  The liquid temperature during catalyst deactivation and water washing is not particularly limited, but a range of 20 ° C to 100 ° C is preferable. 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 of the polymer (a) containing at least one kind of aromatic vinyl monomer obtained by the method as described above is subsequently subjected to the granulation step (1) ( Also called crumb process). The solid content (resin content) concentration of the polymer (a) in the polymer solution at the time of granulation is adjusted to 10 to 60% by weight by adding the solvent used for the polymerization as necessary. It is desirable to make it. If it is less than 10% by weight, the productivity will be extremely reduced, and if it exceeds 60% by weight, it will be difficult to produce a granular material. When the polymer solution concentration is low, the concentration can be adjusted to a desired concentration by using one or more evaporators such as flash evaporation, thin film evaporation, stirring tank, and wet wall type. When the polymer solution concentration is high, it can be adjusted to a desired concentration by diluting the solvent.

  The purified polymer solution containing the polymer (a) 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, water, and if necessary The step of forming the resin granules by removing the solvent by heating while adding the surfactant and dispersing the liquid-liquid by stirring (powder granulation step (1)), the resin granules The aqueous dispersion containing can be obtained. The amount of water to be added is not particularly limited, but is preferably 0.5 to 4 times the volume of the solution containing the polymer (a) from the viewpoint of ease of liquid-liquid dispersion.

  As the surfactant, a nonionic surfactant is preferably used because of its low foaming. Specific examples of nonionic surfactants include glycerin fatty acid ester, sorbitan ester, propylene glycol fatty acid ester, sucrose fatty acid ester, citric acid mono (di or tri) stearate ester, pentaerythritol fatty acid ester, trimethylolpropane fatty acid ester , Polyglycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyester, polyoxyethylene sorbitan fatty acid ester, polyethylene glycol fatty acid ester, polypropylene glycol fatty acid ester, polyoxyethylene glycol fatty alcohol ether, polyoxyethylene alkylphenyl ether, N, N -Bis (2-hydroxyethylene) fatty amine, condensation product of fatty acid and diethanol, polyoxyethylene Block polymers of polyoxypropylene, polyethylene glycol, polypropylene glycol and. These may be used singly or in combination of two or more. The amount of the nonionic surfactant to be added is not particularly limited, but is preferably 0.05% by weight to 5% by weight with respect to 100% by weight of the polymer (a). If it is less than 0.05% by weight, the properties as a surfactant cannot be sufficiently exhibited, and particles may not be formed. On the other hand, if it exceeds 5% by weight, the physical properties of the weight body (a) may be deteriorated, and foaming problems may be noticeable at the time of granulation.

  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. These can be used for liquid-liquid dispersion operation and solvent removal operation 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 at the time of solvent evaporation 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 inside 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. If it is less than 70 ° C., the solvent removal rate may decrease, which may be undesirable in terms of production efficiency. On the other hand, when the temperature is 130 ° C. or higher, the function of the nonionic surfactant may be lost and a stable liquid-liquid dispersion may not be formed.

  Although it does not specifically limit as a heating method, The method of attaching an external jacket and an internal coil to the stirring tank used by process (1), heating, the method of throwing in vapor | steam directly inside a stirring tank, and an electric heater etc. are attached to a stirring tank. A method, a method of extracting a part of the liquid in the stirring tank, heating it with a heat exchanger or the like, and circulating it can be used. As a specific example, when water vapor is directly added, the water vapor temperature is preferably 110 ° C. or higher for ease of treatment, and lower than 130 ° C. in order to maintain the function of the nonionic surfactant.

  After passing through the step (1), the aqueous dispersion containing the resin particles thus obtained contains aqueous particles containing copolymer (b) particles composed of an acrylic monomer and an aromatic vinyl monomer. Add the emulsion.

  Examples of the acrylic monomer in the copolymer (b) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, and n-butyl (meth) acrylate. , T-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, trimethylolpropane Examples include tri (meth) acrylate. These may be used alone or in combination of two or more. Of these, methyl methacrylate, n-butyl methacrylate or a mixture thereof is preferable from the viewpoint of cost, and methyl methacrylate is particularly preferable.

  The aromatic vinyl monomer in the copolymer (b) 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. Among these, styrene, p-methylstyrene, α-methylstyrene or a mixture thereof is preferable from the viewpoint of cost, and styrene is particularly preferable.

  As a ratio of the acrylic monomer and the aromatic vinyl monomer in the copolymer (b), the acrylic monomer is 50 to 70% by weight, and the aromatic vinyl monomer is 30 to 50%. It is preferable from a viewpoint of the transparency of a resin granular material to become weight%.

  The copolymer (b) comprising an acrylic monomer and an aromatic vinyl monomer is obtained by initiating polymerization of an aromatic vinyl monomer after initiating polymerization of the acrylic monomer. It is preferable that The polymerization of the aromatic vinyl monomer is more preferably started after 30% by weight or more of the total amount of the acrylic monomer has been polymerized, and more preferably started after 60% by weight or more has been polymerized. It is particularly preferred to start after 90% by weight or more has been polymerized.

  The method for preparing the aqueous emulsion is not particularly limited, but it can be obtained by emulsion polymerization of the polymerizable monomer in the presence of an aqueous solvent, a polymerization initiator, an emulsifier and the like. The obtained aqueous emulsion can be used as it is in the production method of the present invention.

  As the polymerization initiator, a known radical polymerization initiator can be used, and a water-soluble or oil-soluble polymerization initiator, a thermal decomposition type or a redox type polymerization initiator, or the like is used. For example, usual inorganic initiators such as persulfates, organic peroxides, azo compounds, etc. are used alone, or the above compounds and sulfites, hydrogen sulfites, thiosulfates, first metal salts, sodium formaldehyde sulfoxy You may combine a rate etc. and use it by a redox system. Preferred persulfates as the polymerization initiator include, for example, sodium persulfate, potassium persulfate, and ammonium persulfate. Preferred organic peroxides include, for example, t-butyl hydroperoxide, cumene hydroperoxide, peroxide. Examples include benzoyl oxide and lauroyl peroxide.

  Further, known emulsifiers are used as the above-mentioned emulsifiers, for example, anionic surface activity such as fatty acid salt, alkyl sulfate ester salt (such as sodium dodecyl sulfate), alkylbenzene sulfonate salt, alkyl phosphate ester salt, sulfosuccinic acid diester salt. And nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene fatty acid esters. Preferred anionic surfactants include sodium dodecylbenzenesulfonate. Furthermore, by using potassium persulfate as a polymerization initiator, an aqueous emulsion containing copolymer (b) particles composed of an acrylic monomer and an aromatic vinyl monomer is prepared by soap-free. Also good.

  There are no particular limitations on the temperature, time, and the like when polymerizing the copolymer (b), and the copolymer (b) may be appropriately adjusted so as to have a desired specific viscosity and particle size according to the purpose of use.

  The amount of the copolymer (b) added as an aqueous emulsion is 0.01 wt% to 5 wt% in solid content (polymer amount) with respect to 100 wt% of the polymer (a) in the resin granule. % Is preferred. If it is less than 0.01% by weight, the effect as an anti-blocking agent may not be sufficient. On the other hand, if it exceeds 5% by weight, the physical properties of the resin powder, particularly the mechanical properties such as the tensile strength, may be significantly deteriorated.

  The average particle size of the copolymer (b) particles comprising the acrylic monomer and the aromatic vinyl monomer is not particularly limited, but the average particle size is 0.1 to 0.3 μm. Is preferred. When the particle size is less than 0.1 μm, the transparency of the resin after drying is good, but the effect of improving the blocking resistance is insufficient because the adhesion of the copolymer (b) to the resin surface is not sufficient. There is a case. When the particle diameter exceeds 0.3 μm, the blocking prevention efficiency is lowered, so that a larger amount of addition is required, which may adversely affect mechanical properties such as strength.

In the present invention, the average particle diameter is measured as a volume average diameter (MV [μm]) using a general dynamic light scattering particle size distribution measuring device such as “Microtrack UPA” manufactured by Honeywell. . The volume average diameter (MV [μm]) refers to an average diameter weighted by volume, and is an average diameter generally defined by Equation (1).
MV = Σ (V _i · d _i ) / Σ (V _i ) Equation (1)
V _i [(μm) ³ ]: Volume of particle i (i = 1, 2,..., N)
d _i [μm]: diameter of the particle i (i = 1, 2,..., N)
The refractive index of the copolymer (b) particles composed of an acrylic monomer and an aromatic vinyl monomer is not particularly limited, but the resin granules composed of the polymer (a) and the above copolymer ( The difference in refractive index from b) is preferably within 0.1. If the difference in refractive index is 0.1 or more, the transparency of the product sheet produced using the resin powder may not reach the level required by the market depending on the application.

In the present invention, the refractive index is obtained by estimating from the refractive index of each monomer according to an additivity rule generally defined by equation (2).
z = Σ (Ax + By) / Σ (A + B) Equation (2)
z: estimated refractive index of resin [-], A: monomer ratio [%], B: monomer ratio [%], x: A monomer refractive index [-], y: B monomer refractive index [-]
The refractive index of the monomer is POLYMER HANDBOOK THIRD EDITION Edited by J. BRANDRUP and E. H. It is a value described in IMMERGUT.

  Furthermore, after adding the aqueous emulsion containing the copolymer (b) particles composed of an acrylic monomer and an aromatic vinyl monomer to the resin particle-containing aqueous solution, an inorganic salt is further added. Is preferable in that the copolymer (b) in the resin particle-containing aqueous dispersion can be efficiently attached to the surface of the resin particle. The inorganic salt to be added is not particularly limited, but ammonium chloride, zinc chloride, aluminum chloride, tin chloride, nickel chloride, antimony chloride, ferrous chloride, ferric chloride, copper chloride, sodium chloride, magnesium chloride, chloride Inorganic chlorides such as lithium, barium chloride, calcium chloride, potassium bromide, sodium sulfite, sodium bisulfite, potassium sulfite, potassium bisulfite, ammonium sulfite, ammonium bisulfite, magnesium sulfite, magnesium bisulfite, calcium sulfite, bisulfite Calcium, potassium aluminum sulfate, ferrous sulfate, nickel sulfate, zinc sulfate, magnesium sulfate, sodium hydrogen sulfate, aluminum sulfate, sodium aluminum sulfate, titanium sulfate, nickel ammonium sulfate, manganese sulfate Chromium sodium sulfate, tin hydrogen sulfate, copper sulfate, iron sulfate, ammonium persulfate, potassium sulfate, sodium sulfate, ammonium sulfate and other sulfites or sulfates, potassium carbonate, ammonium carbonate, sodium carbonate, sodium hydrogen carbonate and other carbonates, ammonium nitrate And nitrates such as nickel nitrate and sodium nitrate. Among them, sodium chloride, sodium sulfate, sodium sulfite, and sodium nitrate are preferable from the viewpoint of the effect of improving the blocking resistance. Among them, sodium sulfate is the effect of improving the blocking resistance, low corrosiveness to the device, and safety. Is more preferable.

  The amount of the inorganic salt to be added is not particularly limited, but from the viewpoint of the effect of improving blocking resistance, low corrosiveness to the device, and safety, the solution containing the resin particles [inorganic salt (mmol) It is preferable to add such that the ratio of / water (liter (L)) in the aqueous dispersion is 20 mmol / L or more and not more than the saturated solubility in water.

  As above-mentioned, after adding an aqueous emulsion, a resin granular material is collect | recovered from the obtained mixture. At the time of collection, an aqueous emulsion containing particles of a copolymer (b) composed of an acrylic monomer and an aromatic vinyl monomer is added to an aqueous dispersion containing resin particles. Then, heat treatment may be performed with stirring (steam stripping step (2)). By passing through the steam stripping step, the remaining solvent can be further removed, and at the same time, the added copolymer (b) can be efficiently adhered to the surface of the resin powder. Thereby, it is possible to improve the blocking resistance of the resin particles after dehydration, and it is possible to perform a good dispensing without clogging with a recovery hopper or piping. In addition, the dehydrated resin granules are not blocked in the process before drying, and further, deterioration of the quality of the obtained product can be prevented, and in particular, it can be stably manufactured without impairing transparency. In the case of an isobutylene block copolymer, the heating temperature during the treatment is preferably 70 ° C. or more and less than 180 ° C. in order to effectively attach the copolymer (b) to the surface of the resin powder. . When it is less than 70 ° C., the copolymer (b) does not adhere to the resin efficiently, and the effect of blocking resistance may not be sufficient. On the other hand, when the temperature is 180 ° C. or higher, fusion between the resins becomes remarkable and coarse particles may be generated.

  The vessel used for the steam stripping step (2) 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 operation. 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 steam stripping is not particularly limited, but can be dehydrated and dried by the step (3) described below. For example, in order to recover the resin particles from an aqueous solution containing the resin particles, the resin particles can be recovered by performing a dehydration operation using various filters, centrifuges, and the like. The water content of the resin powder after dehydration by this operation is not particularly limited, but it is effective in terms of energy efficiency during drying 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.

  Further, although not particularly limited, the dehydrated water-containing resin particles or the dried product particles can be produced as resin pellets 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.

  According to the production method of the present invention, it is possible to improve the blocking resistance without deteriorating the quality of the obtained resin granules and particularly without impairing the transparency.

  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.

Each physical property of the block copolymer shown in the present Example was measured by the method shown below.
(Molecular weight)
Waters GPC system (column: Shodex K-804 (polystyrene gel), Showa Denko KK, mobile phase: chloroform). The number average molecular weight is expressed in terms of polystyrene.
(Transparency of product sheet)
A 2 mm thick press sheet is prepared using the resin powder obtained by the production method of the present invention, and the Haze value (turbidity) and transparency of the sheet are measured by Nippon Denshoku Industries Co., Ltd. HazeMeter (turbidimeter) NDH2000. It was measured.
(Blocking resistance)
Regarding the blocking resistance of the obtained resin granules, 40 g of the resin granules were filled into a cylinder having an inner diameter of 5 cm, and the piston was subjected to a load of 0.03 MPa and stored in a 60 ° C. atmosphere for 15 hours. The mixture was allowed to stand at room temperature for 3 hours to prepare a block of resin particles. In order to determine the breaking strength of this block, the load applied to break the resin powder block was measured using a FUDOH RHEO METER (Rheometer) manufactured by Rheotech Co., Ltd., and the resin was expressed by the following equation (3). The adhesion of the powder was obtained and used as an index of blocking resistance.
σ = 2 × P / π × d × h × 10 × 0.098 Equation (3)
Here, σ: adhesion force [kPa], P: load [g], d = 5 cm: block inner diameter, h: block height [cm].
(Particle size)
The particle diameter of the copolymer (b) particles composed of an acrylic monomer and an aromatic vinyl monomer is determined using a general dynamic light scattering particle size distribution analyzer such as “Microtrack UPA” manufactured by Honeywell. The volume average diameter was measured.
(Refractive index)
The refractive index of the polymer powder (a) and the refractive index of the copolymer (b) composed of an acrylic monomer and an aromatic vinyl monomer are defined in advance from the refractive index of each monomer. It was obtained by estimating according to an additivity rule generally defined by equation (2).
(Production Example 1)
To a 20 L reaction vessel equipped with a stirrer, 1.70 kg of 1-chlorobutane (water removed with molecular sieves), 1.92 kg of hexane (water removed with molecular sieves), and 2.90 g of p-dicumyl 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. Further, 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 an isobutylene block copolymer (a) solution.

  The obtained polymer (a) 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. After washing the polymer solution phase twice with the same method, after confirming that the aqueous layer is neutral, the polymer solution phase is discharged and contains the isobutylene block copolymer (a) A solution was obtained.

As a result of GPC analysis, the polymer (a) had a number average molecular weight of 100,000 and a molecular weight distribution of 1.14.
(Production Example 2)
To an 8 L reactor equipped with a stirrer, 3910.3 g of pure water was charged, 53.3 g of sodium dodecylbenzenesulfonate and 320 g of methyl methacrylate monomer were added, nitrogen was bubbled at 2.0 L / min, and the temperature was raised for 30 minutes. Stir at 100 rpm. When the liquid temperature reached 68 ° C., 40 g of potassium persulfate was added, the nitrogen flow rate was lowered to 0.2 L / min, and the mixture was stirred at 210 rpm to initiate polymerization. The polymerization temperature is 70 ° C. After the start, 640 g of methyl methacrylate monomer was continuously injected with a pump over 2 hours and post-polymerized for 30 minutes after the injection. At this time, about 98% of the total amount of methyl methacrylate monomer added was consumed by polymerization. Thereafter, 640 g of styrene monomer was continuously injected with a pump over another 2 hours. After the injection, 16 g of sodium formaldehydesulfoxylate was added, and stirring was completed for 60 minutes. An aqueous emulsion containing particles of a copolymer consisting of methyl methacrylate and styrene obtained by the above method was obtained.

The particle diameter of the obtained copolymer (b) particles was 0.12 μm in terms of volume-based average diameter. The solid content concentration of the aqueous emulsion was 27.3%.
(Production Example 3)
In Production Example 2, 800 g of methyl methacrylate monomer was continuously injected by a pump over 2.5 hours after the start of polymerization, and post-polymerization was performed for 30 minutes after the injection. At this time, about 98% of the total amount of methyl methacrylate monomer added was consumed by polymerization. Then, it is the same method as Production Example 2 except that 480 g of styrene monomer is continuously injected with a pump over 1.5 hours. The particle diameter of the obtained copolymer (b) particles was 0.12 μm in terms of volume-based average diameter. The solid content concentration of the aqueous emulsion was 27.7%.
(Production Example 4)
In Production Example 2, 480 g of methyl methacrylate monomer was continuously injected with a pump over 1.5 hours after the start of polymerization, and post-polymerized for 30 minutes after the injection. At this time, about 98% of the total amount of methyl methacrylate monomer added was consumed by polymerization. Then, it is the same method as Production Example 2 except that 800 g of styrene monomer is continuously injected with a pump over 2.5 hours. The particle diameter of the obtained copolymer (b) particles was 0.12 μm in terms of volume-based average diameter. The solid content concentration of the aqueous emulsion was 27.4%.
(Production Example 5)
In Production Example 2, a mixed solution in which 320 g of methyl methacrylate monomer and 320 g of styrene monomer were preliminarily mixed over 2 hours after the start of polymerization was continuously injected by a pump, followed by post-polymerization for 30 minutes after injection, This is the same method as in Production Example 2 except that a mixed solution in which 320 g of methyl methacrylate monomer and 320 g of styrene monomer were mixed in advance for 2 hours was continuously injected by a pump. The particle diameter of the obtained copolymer (b) particles was 0.12 μm in terms of volume-based average diameter. The solid content concentration of the aqueous emulsion was 27.7%.
(Production Example 6)
In a 2 L reaction vessel equipped with a stirrer, 269 g of styrene monomer (extracted by removing the polymerization inhibitor with a caustic aqueous solution), 903 g of distilled water adjusted to pH 10 with caustic soda, and 1.5 g of sodium dodecyl sulfate were added. The mixture was stirred for 60 minutes while heating to 70 ° C. Thereafter, 0.75 g of potassium persulfate was added and reacted for 4 hours to obtain an aqueous emulsion containing polystyrene particles. The particle size of the obtained polystyrene particles was 0.13 μm in a volume-based average system. The solid content concentration of the aqueous emulsion was 27.3%.
Example 1
A pressure-resistant stirrer having a stirring tank volume of 50 L and an inner diameter of 30 cm is charged with 7.2 L of pure water and 11.3 L of a polymer solution containing the isobutylene block copolymer (a) obtained in Production Example 1 to obtain a nonionic surface activity. 9.73 g of an agent (polyethylene glycol monostearate) was added and sealed. As the stirring blade, a two-stage four-padded paddle with a blade diameter of 15 cm was used, and the temperature was raised by introducing steam from the lower part of the stirring tank while stirring at 600 rpm.

  When the internal temperature of the stirring tank reached 99 ° C., the introduction of steam was stopped, the stirring was stopped after the internal temperature became 60 ° C. or less, and the resin slurry (aqueous dispersion) produced in the stirring tank was recovered. (Step (1)). The resin particles in the recovered resin slurry had a particle size of 1 to 5 mm and were particles with an appropriate particle size.

  Next, 200 g of recovered resin particles, 500 g of a slurry solution (aqueous solution only), and a copolymer of methyl methacrylate and styrene obtained in Production Example 2 (b) are placed in a pressure-stirring device having a stirring tank volume of 3 L and an inner diameter of 12 cm. 4.39 g of an aqueous emulsion containing particles (in which the solid content (copolymer (b) particles) is equivalent to 1.2% by weight with respect to 100% by weight of the polymer (a)), 10% concentration 30 g of sodium sulfate (amount corresponding to 3% by weight with respect to 100% by weight of the polymer (a)) was added and sealed, and steam stripping was performed (step (2)). Stripping was performed by blowing steam from the lower part of the stirring tank while maintaining an atmospheric temperature of 135 ° C. for 30 minutes.

  The obtained resin slurry was centrifugally dehydrated to obtain resin powder particles. 40 g of the dehydrated resin powder is filled in a cylinder having an inner diameter of 5 cm, and is stored at 60 ° C. for 15 hours under a load of 0.03 MPa with a piston, and then left at room temperature for 3 hours. The powder particles were measured for blocking resistance with a rheometer.

  Furthermore, a 2 mm thick press sheet was prepared using the resin particles after dehydration, and the haze value (turbidity) and transparency of the sheet were measured with a turbidimeter.

Table 1 shows the measurement results of blocking resistance, haze value (turbidity) and transparency.
(Example 2)
In step (2), 4.33 g of the aqueous emulsion containing the copolymer (b) particles of methyl methacrylate and styrene obtained in Production Example 3 (solid content (100% by weight of polymer (a)) The same procedure as in Example 1 was conducted except that the amount of the copolymer (b) particles) was 1.2% by weight. Table 1 shows the measurement results of blocking resistance, haze value (turbidity) and transparency.
(Example 3)
In step (2), 4.39 g of the aqueous emulsion containing the copolymer (b) particles of methyl methacrylate and styrene obtained in Production Example 4 (solid content (100% by weight of polymer (a)) The same procedure as in Example 1 was conducted except that the amount of the copolymer (b) particles) was 1.2% by weight. Table 1 shows the measurement results of blocking resistance, haze value (turbidity) and transparency.
Example 4
In step (2), 4.33 g of the aqueous emulsion containing the copolymer (b) particles of methyl methacrylate and styrene obtained in Production Example 5 (solid content (100% by weight of polymer (a)) The same procedure as in Example 1 was conducted except that the amount of the copolymer (b) particles) was 1.2% by weight. Table 1 shows the measurement results of blocking resistance, haze value (turbidity) and transparency.
(Comparative Example 1)
In the step (2), an additive such as an anti-blocking agent was not used, and steam stripping was performed in the same manner as in Example 1 except that 200 g of recovered resin particles and 500 g of a slurry solution (aqueous solution only) were used. Carried out. Table 1 shows the measurement results of blocking resistance, haze value (turbidity) and transparency.
(Comparative Example 2)
In the step (2), 4.39 g of the aqueous emulsion containing the polystyrene particles obtained in Production Example 6 (solid content (copolymer (b) particles) is 1 with respect to 100% by weight of the polymer (a)). The amount was equivalent to 2% by weight). Table 1 shows the measurement results of blocking resistance, haze value (turbidity) and transparency.

以下に表１の説明を示す。

The description of Table 1 is shown below.

  MMA is an abbreviation for methyl methacrylate and St is an abbreviation for styrene. The smaller the values of blocking resistance and haze value (turbidity), the better. The greater the value of transparency, the better. Furthermore, regarding the expression of the monomer composition, for example, MMA (60%) and St (40%) represent the monomer ratio charged in the preparation of the copolymer, MMA is 640 g + 320 g = 960 g, and St is 640 g. In the case of 960: 640 = 60: 40, it is expressed as MMA (60%) and St (40%).

Claims (14)

Adding water to a solution containing the polymer (a) containing at least one aromatic vinyl monomer component, and forming a resin granule by heating and stirring; and
Adding an aqueous emulsion containing particles of a copolymer (b) composed of an acrylic monomer and an aromatic vinyl monomer to the obtained resin particle-containing aqueous dispersion;
And a step of recovering the resin particles from the obtained mixture.   The copolymer (b) comprising an acrylic monomer and an aromatic vinyl monomer comprises 50 to 70% by weight of an acrylic monomer and 30 to 50% by weight of an aromatic vinyl monomer. The manufacturing method of the resin granular material of Claim 1 characterized by these.   The copolymer (b) comprising an acrylic monomer and an aromatic vinyl monomer is obtained by initiating polymerization of an aromatic vinyl monomer after initiating polymerization of the acrylic monomer. The method for producing a resin granule according to claim 1 or 2, wherein the resin granule is produced.   50% by weight or more of the portion derived from the acrylic monomer in the copolymer (b) comprising the acrylic monomer and the aromatic vinyl monomer is derived from methyl methacrylate. The manufacturing method of the resin granular material of any one of Claims 1-3.   The said polymer (a) has a block which has an aromatic vinyl monomer as a main component, The manufacturing method of the resin granular material of any one of Claims 1-4 characterized by the above-mentioned.   6. The polymer according to claim 1, wherein the polymer (a) is an isobutylene polymer obtained from at least one aromatic vinyl monomer and an isobutylene monomer. The manufacturing method of the resin granular material as described in 2 .. The polymer (a) is
(A) a polymer block composed mainly of isobutylene;
(B) a polymer block composed mainly of an aromatic vinyl monomer;
It is a block copolymer which consists of this, The manufacturing method of the resin granular material of any one of Claims 1-6 characterized by the above-mentioned.   The difference in refractive index between the resin particles comprising the polymer (a) and the copolymer (b) comprising an acrylic monomer and an aromatic vinyl monomer is within 0.1. The method for producing a resin particle according to any one of claims 1 to 7.   The average particle diameter of the said copolymer (b) which consists of an acryl-type monomer and an aromatic vinyl-type monomer is 0.1-0.3 micrometer, The any one of Claims 1-8 characterized by the above-mentioned. The manufacturing method of the resin granular material as described in a term.   The amount of particles of the copolymer (b) composed of an acrylic monomer and an aromatic vinyl monomer relative to 100 parts by weight of the polymer (a) constituting the resin particle is a solid content. It is 0.01-5 weight part by weight, The manufacturing method of the resin granular material of any one of Claims 1-9 characterized by the above-mentioned.   The method for producing a resin granular material according to any one of claims 1 to 10, further comprising a step of adding an inorganic salt after adding the aqueous emulsion.   The method for producing a resin granular material according to claim 11, wherein the inorganic salt to be added is sodium sulfate. The method for producing a resin granule according to claim 11 or 12, wherein the inorganic salt is added so that a ratio of (inorganic salt / water in the aqueous dispersion) is 20 mmol / L or more.   After adding the aqueous emulsion containing particles of the copolymer (b) composed of an acrylic monomer and an aromatic vinyl monomer to the resin particle-containing aqueous dispersion, 70 ° C. or higher The method for producing a resin granule according to any one of claims 1 to 13, wherein the mixture is heat-treated at less than 180 ° C.