JP2011241341A - Method for decreasing remaining volatile component of thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for continuously separating volatile components such as an un-reacted monomer, solvent, volatile byproducts or impurities from a thermoplastic resin composition obtained by a graft polymerization method by using a melt-kneader (hereinafter, an extruder).SOLUTION: By showering a cooling medium against the resin composition formed as strands from the tip end of the extruder (hereinafter, dies) after performing the melt-kneading polymerization, it is possible to decrease the volatile components contained in the resin composition and especially decrease the un-reacted monomer component effectively.

Description

  The present invention continuously removes volatile components such as unreacted monomers, solvents, volatility, by-products or impurities from a thermoplastic resin composition obtained by a graft polymerization method using a melt kneader (hereinafter referred to as an extruder). The present invention relates to a method for reducing volatile matter.

  The modification of the resin using an extruder is performed by kneading polymerization by adding a modifying monomer to a base resin melted and kneaded in an extruder using a raw material obtained by mixing a predetermined amount of a polymerization initiator with a resin as a base material. I do. In order to remove unreacted monomer volatile substances and moisture contained in the raw material, a volatile component outlet (hereinafter referred to as a vent) having an opening for communicating the inside and outside of the barrel downstream of the kneading part of the extruder Is provided. In addition, a vacuum device is connected to the vent, and unreacted monomers and moisture generated from the inside of the extruder are forcibly discharged.

  However, as the operation of the extruder (melt kneading polymerization of the thermoplastic resin composition) continues, the polymer composition may gradually adhere to the vent and harden, closing the opening. In such a case, the pressure difference between the inside and the outside of the barrel causes so-called vent-up in which the polymer composition attached to the vent opening is pushed up. In such a state, the operation of the extruder must be interrupted for maintenance, and the production efficiency is significantly hindered. Therefore, a proposal has been made to provide a dedicated apparatus for removing volatile components. For example, Patent Document 1 describes a screw-type degassing extruder in which the axial distance from the vent is 3D or more when the screw diameter is D. Yes. Patent Document 2 describes a thermoplastic composition melting and kneading apparatus in which a volatile component removing unit is equipped with a heating device.

  In the method of providing a dedicated degassing extruder, although the extruder for performing melt-kneading polymerization and the dedicated degassing extruder can be arranged in tandem, the equipment cost is high and an inexpensive manufacturing apparatus may not be obtained. In addition, the method of heating the vent is insufficient to prevent vent-up, and particularly when the thermoplastic resin composition is kneaded and polymerized by adding a large amount of the modifying monomer, the screw is low because the thermoplastic resin component is small. In some cases, the resin composition peeled off frequently, and the vent-up could not be completely suppressed.

JP-A-3-49925 JP 2007-290384 A

  In order to avoid the problem due to forced exhaustion of volatile components by venting as described above, the present invention does not rely on forced exhaustion of volatile components by venting, and the unreacted monomer, solvent, volatility from the extruded resin composition, The present invention provides a method that enables separation and reduction of volatile components such as by-products or impurities.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor, after performing melt-kneading polymerization, showers the cooling medium on the resin composition formed into a strand shape from the tip of the extruder (hereinafter referred to as a die). Thus, the volatile matter contained in the resin composition can be reduced, in particular, the unreacted monomer component can be effectively reduced, and the present invention has been completed.

  That is, the present invention is as follows.

  1) A method for reducing residual volatile components of a thermoplastic resin composition in which a strand-shaped thermoplastic resin composition is brought into contact with a cooling medium.

  2) The method for reducing residual volatile components of the thermoplastic resin composition according to 1), wherein the molten resin extruded in a strand shape by the extruder is stretched in the take-off direction, and then the cooling medium is dispersed by showering.

  3) The thermoplasticity according to either 1) or 2), wherein the showering cooling medium is water, and the amount of water is 50 L / min or less per 50 Kg / Hr of the extruded molten resin. A method for reducing residual volatile components of a resin composition.

  4) The method for reducing residual volatile components of the thermoplastic resin composition according to any one of 1) to 3), wherein a temperature of the showering water is 50 ° C. or less.

  5) The method for reducing residual volatile components of the thermoplastic resin composition according to any one of 1) to 4), wherein the thermoplastic resin polymerization composition is a modified polyolefin resin.

  6) The modified polyolefin resin melt kneaded a compound containing an ethylenic double bond and a polar group in the same molecule and an aromatic vinyl monomer in the presence of a radical polymerization initiator with respect to the polyolefin resin. Ethylene double bond and polarity in a total of 100% by weight of a polyolefin resin, a compound containing an ethylenic double bond and a polar group in the same molecule, an aromatic vinyl monomer and other vinyl monomers. Reduction of residual volatile components of the thermoplastic resin composition according to 5), wherein the proportion of the compound containing a group in the same molecule is a modified polyolefin resin in the range of 0.05 to 50% by weight Method.

  7) The compound containing the ethylenic double bond and the polar group in the same molecule is at least one selected from the group consisting of an unsaturated carboxylic acid, an anhydride, a derivative thereof, and an epoxy group-containing vinyl monomer. A method for reducing residual volatile components of a thermoplastic resin composition according to 6).

  8) The compound containing the ethylenic double bond and the polar group in the same molecule is at least one selected from the group consisting of (meth) acrylic acid, maleic anhydride, and glycidyl (meth) acrylate 7) The method for reducing residual volatile components as described in 1.

  The present invention is effective in separating volatile components such as unreacted monomers, solvents, volatility, by-products or impurities from a resin composition discharged from an extruder. By showering the cooling medium on the resin composition discharged from the extruder, the volatile components remaining in the obtained resin composition can be made very small.

  One embodiment of the present invention will be described by a method for separating a residual volatile component contained in a modified resin composition by melt kneading in an extruder.

  A polyolefin resin or the like (hereinafter referred to as a raw material) is supplied to the popper of the extrusion kneader. The raw material supplied to the popper is melted by an extrusion kneader and then guided to a die having pores to obtain a strand-like adhesive resin.

  When using an extrusion kneader to obtain a modified polyolefin resin, use a mixture of a predetermined amount of a polyolefin resin and a radical polymerization initiator as a raw material, melt it with an extrusion kneader, and supply the modifying monomer from the addition port. Kneading polymerization can be performed. In this case, a low molecular weight material generated by polymerization may be removed by opening a vent provided at the tip of the extrusion kneader. The position of the vent is 4D or more and 10D or less from the tip, and in the case of 4D or less, since it is close to the discharge port, there is a danger of venting up due to the temperature drop of the barrel. When it exceeds 10D, the reaction zone becomes short and the reaction rate may be lowered, which is not preferable.

  The molten resin guided to the die is formed into strands by the pores. The formed strand is dropped vertically by gravity, received by a conveyor, and conveyed while adjusting the line speed appropriately while showering the cooling medium. Next, it guide | induces in a cooling tank, a strand is cut | disconnected with a pelletizer, and a resin pellet is formed.

  Although there is no restriction | limiting in particular in the kind of cooling medium used for showering used by this invention, It is preferable to use water from the point of economical efficiency and handleability. Further, a solid or liquid self-adhesion preventing agent may be added to the cooling medium.

  Moreover, it is preferable to use water for the cooling medium of the cooling tank used in the present invention in terms of economy and handling.

  The number of resin strands extruded from the extruder die is not limited to one, and a plurality of resin strands may be extruded simultaneously. In particular, it is preferable to apply the present invention when a plurality of strands are extruded simultaneously.

    Although the amount of showering water is not particularly limited, it is preferably 50 L / min or less and 0.1 L / min or more per 50 kg / hr of extruded resin. If the water supply capacity exceeds 50 L / min, the equipment cost may not be low. When the amount of showering water is less than 0.1 L / min, the cooling of the strand may be insufficient.

  The showering water temperature is preferably 50 ° C. or lower. If it exceeds 50 ° C., although it depends on the line speed, the strand cannot be cooled and may break at the conveyor discharge port, causing trouble.

  By controlling the amount of cooling water per extruded resin and the cooling water temperature, residual volatile components of the melt-kneaded resin can be reduced.

  The resin composition to which the present invention is applied is not particularly limited as long as it is a melt-kneaded resin composition, but is particularly effective when it is an adhesive resin composition.

<< About adhesive resin >>
Resins that are soft and adhesive at room temperature, such as polyisobutylene, butyl rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, styrene-isoprene-styrene rubber, styrene-ethylene-butadiene-styrene rubber, acrylic rubber, acrylic acid Examples thereof include olefin rubbers such as ester-acrylonitrile copolymer rubber, chlorosulfonated polyethylene rubber and fluororubber, and vulcanized and unvulcanized elastomers. An example of an adhesive resin obtained by extrusion polymerization is a compound containing a certain amount of an ethylenic double bond and a polar group in the same molecule, aromatic vinyl in the presence of a radical polymerization initiator for a polyolefin resin. Examples thereof include modified polyolefin resins obtained by melt-kneading monomers and other vinyl monomers.

<< About modified polyolefin resin >>
Examples of the polyolefin resin used for the modified polyolefin resin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, random copolymer or block copolymer in any ratio of propylene and ethylene and / or 1-butene. Cyclic compounds such as copolymers, ethylene-propylene-diene terpolymers having a diene component of 50% by weight or less in all ratios of ethylene and propylene, and copolymers of polymethylpentene, cyclopentadiene and ethylene and / or propylene Examples thereof include random copolymers and block copolymers of polyolefin, ethylene or propylene and 50% by weight or less of a vinyl compound.

  Among these, polypropylene, polyethylene, and polyisobutylene are preferable from the viewpoint of balance of physical properties, availability, and price, and those having polyethylene and polypropylene as main components are particularly preferable. The thing which has a polypropylene as a main component means the polymer which contains a propylene unit 50weight% or more, and is the same also about the thing which has a polyethylene as a main component.

  In addition, a polyolefin resin into which a polar group is introduced can also be used because it is easily compatible with the unsaturated carboxylic acid monomer having a polar group used at the time of modification. Specific examples of polyolefin resins having polar groups introduced include acid-modified polypropylene such as maleic anhydride-modified polypropylene, maleic acid-modified polypropylene, and acrylic acid-modified polypropylene; ethylene / vinyl chloride copolymer, ethylene / vinylidene chloride copolymer , Ethylene / acrylonitrile copolymer, ethylene / methacrylonitrile copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylamide copolymer, ethylene / methacrylamide copolymer, ethylene / acrylic acid copolymer, ethylene / Methacrylic acid copolymer, ethylene / maleic acid copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / isopropyl acrylate copolymer, ethylene / butyl acrylate copolymer, Ethylene / A Isobutyl acrylate copolymer, ethylene / 2-ethylhexyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer, ethylene / isopropyl methacrylate copolymer, ethylene / butyl methacrylate Copolymer, ethylene / isobutyl methacrylate copolymer, ethylene / 2-ethylhexyl methacrylate copolymer, ethylene / maleic anhydride copolymer, ethylene / ethyl acrylate / maleic anhydride copolymer, ethylene / acrylic acid Metal salt copolymer, ethylene / methacrylic acid metal salt copolymer, ethylene / vinyl acetate copolymer or saponified product thereof, ethylene / vinyl propionate copolymer, ethylene / glycidyl methacrylate copolymer ethylene / acrylic acid Ethyl / glycidyl methacrylate copolymer , Ethylene or α- olefin / vinyl monomer copolymers such as ethylene / vinyl acetate / glycidyl methacrylate copolymer; and chlorinated polyolefins such as chlorinated polypropylene chlorinated polyethylene. These polar group-introduced polyolefins can be used even if mixed.

  You may add other resin or rubber | gum to the said raw material polyolefin resin as needed.

  Examples of the other resin or rubber include poly α-olefins such as polypentene-1 and polymethylpentene-1; ethylene or α-olefins such as a propylene / butene-1 copolymer having a propylene content of less than 75% by weight. / Α-olefin copolymer; ethylene or α-olefin / α-olefin / diene monomer copolymer such as ethylene / propylene / 5-ethylidene-2-norbornene copolymer having a propylene content of less than 75% by weight Polymer; Polydiene copolymer such as polybutadiene and polyisoprene; Vinyl monomer / diene monomer random copolymer such as styrene / butadiene random copolymer; Vinyl such as styrene / butadiene / styrene block copolymer Monomer / Diene monomer / Vinyl monomer block copolymer; Hydrogenation ( Hydrogenation such as styrene / butadiene random copolymer) (vinyl monomer / diene monomer random copolymer); Hydrogenation such as hydrogenation (styrene / butadiene / styrene block copolymer) (vinyl single unit) Monomer / diene monomer / vinyl monomer block copolymer); vinyl monomer / diene monomer such as acrylonitrile / butadiene / styrene graft copolymer, methyl methacrylate / butadiene / styrene graft copolymer / Vinyl monomer graft copolymer; vinyl polymers such as polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyvinyl acetate, polyethyl acrylate, polybutyl acrylate, polymethyl methacrylate, polystyrene, etc .; vinyl chloride / Acrylonitrile copolymer, vinyl chloride / vinyl acetate copolymer, acrylonite Le / styrene copolymers, such as vinyl copolymers such as methyl methacrylate / styrene copolymer.

  The amount of these other resins or rubbers added to the polyolefin resin varies depending on the type of the resin or the type of rubber, and may be within the range not impairing the effects of the present invention as described above.

<< About monomers used for modification of polyolefin resin >>
The modification of the polyolefin-based resin is performed using a monomer such as a compound containing an ethylenic double bond and a polar group in the same molecule, an aromatic vinyl monomer, and other vinyl monomers.

  The amount of the compound containing an ethylenic double bond and a polar group in the same molecule is preferably 0.05 to 100 parts by weight, and 0.5 to 50 parts by weight with respect to 100 parts by weight of the polyolefin. Is more preferable. In a preferred amount of use, the adhesiveness of the polyolefin resin can be sufficiently improved, and the generation of polymer components that do not bind to the polyolefin resin can be suppressed.

  Further, the proportion of the compound containing an ethylenic double bond and a polar group in the same molecule is a polyolefin resin, a compound monomer containing an ethylenic double bond and a polar group in the same molecule, and an aromatic vinyl monomer. The total weight is preferably 0.05 to 50% by weight, more preferably 0.5 to 40% by weight, and particularly preferably 1 to 30% by weight.

  As the compound containing an ethylenic double bond and a polar group in the same molecule, it is preferable to use an α, β-unsaturated carboxylic acid or its anhydride monomer and / or an epoxy group-containing vinyl monomer.

  The α, β-unsaturated carboxylic acid or anhydride monomer thereof is an unsaturated mono- or dicarboxylic acid having an ethylenic double bond and a carboxylic acid group or carboxylic anhydride group in the same molecule and These acid anhydrides are acrylic acid, methacrylic acid, maleic acid, endo-bicyclo [2.2.1] -5-heptene-2,3-dicarboxylic acid (endic acid), fumaric acid, tetrahydrophthalic acid Itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadic acid, maleic anhydride, endic acid anhydride, citraconic anhydride, itaconic anhydride, nadic acid anhydride and the like can be exemplified. Among these monomers, acrylic acid, methacrylic acid and maleic anhydride are preferable, and maleic anhydride is more preferable. These may be used individually by 1 type, and may be used in combination of 2 or more types. Among these, maleic anhydride is preferable in terms of adhesion at a low temperature when adhering to a dissimilar material, particularly when adhering to a metal material.

  When an α, β-unsaturated carboxylic acid or its anhydride monomer is used as a compound containing an ethylenic double bond and a polar group in the same molecule, the amount used is 100 parts by weight of polyolefin resin. The amount is preferably 0.05 to 100 parts by weight, more preferably 0.1 to 50 parts by weight, and particularly preferably 0.5 to 20 parts by weight. In the preferred use amount, the adhesiveness of the polyolefin resin can be sufficiently improved, and the removal of the unreacted monomer is facilitated.

  Examples of the epoxy group-containing vinyl monomer include glycidyl methacrylate, glycidyl acrylate, monoglycidyl maleate, diglycidyl maleate, monoglycidyl itaconate, diglycidyl itaconate, monoglycidyl allyl succinate, diglycidyl allyl succinate, p-Styrenecarboxylic acid glycidyl, allyl glycidyl ether, methallyl glycidyl ether, styrene-p-glycidyl ether, p-glycidyl styrene, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1- One type or two or more types of epoxy olefins such as butene, vinylcyclohexene monoxide and the like can be mentioned. Of these, glycidyl methacrylate and glycidyl acrylate are preferable in that they are inexpensive.

  When an epoxy resin-containing vinyl monomer is used as a compound containing an ethylenic double bond and a polar group in the same molecule, the amount used is 0.2 to 100 parts by weight with respect to 100 parts by weight of polyolefin. Is preferable, and it is more preferable that it is 0.5-50 weight part. In a preferred amount of use, the adhesiveness of the polyolefin resin can be sufficiently improved, and the generation of polymer components that do not bind to the polyolefin resin can be suppressed.

  As an example of the aromatic vinyl monomer, styrene; methyl styrene such as o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, β-methyl styrene, dimethyl styrene, and trimethyl styrene; -Chlorostyrene such as chlorostyrene, m-chlorostyrene, p-chlorostyrene, α-chlorostyrene, β-chlorostyrene, dichlorostyrene, trichlorostyrene; o-bromostyrene, m-bromostyrene, p-bromostyrene, dibromo Bromostyrene such as styrene and tribromostyrene; fluorostyrene such as o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, difluorostyrene, and trifluorostyrene; o-nitrostyrene, m-nitrostyrene, p-nitros Nitrostyrene such as len, dinitrostyrene and trinitrostyrene; vinylphenol such as o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene and trihydroxystyrene; o-divinylbenzene, m-divinylbenzene, p 1 type, or 2 or more types, such as-divinylbenzene, such as divinylbenzene; diisopropenylbenzene, such as o-diisopropenylbenzene, m-diisopropenylbenzene, p-diisopropenylbenzene; Of these, methylstyrene such as styrene, α-methylstyrene, p-methylstyrene, divinylbenzene monomer or divinylbenzene isomer mixture is preferable in that it is inexpensive.

  The amount of the aromatic vinyl monomer used is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 40 parts by weight, with respect to 100 parts by weight of the polyolefin resin. Part by weight is particularly preferred. Within a preferred range, polymerization (grafting) of α, β-unsaturated carboxylic acid or its anhydride monomer and / or epoxy resin-containing vinyl monomer to polyolefin can be carried out efficiently.

  Examples of other vinyl monomers include vinyl halides such as vinyl chloride and vinyl bromide, vinyl cyanides such as acrylonitrile and methacrylonitrile, vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, etc. Esters, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl isopropyl ether, vinyl n-butyl ether, vinyl tert-butyl ether and other vinyl ethers, vinylidene chloride, vinylidene fluoride and other halogenated vinylidene fluoride, methyl (meth) acrylate, Ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, benzyl (meth) acrylate, (meth ) Phenylethyl acrylic acid, (meth) naphthyl acrylate. These monomers may be used alone or in combination of two or more. Among these, a (meth) acrylic acid ester monomer is preferable, and more preferable than methyl (meth) acrylate.

<< About radical polymerization initiator >>
Examples of radical polymerization initiators generally include peroxides and azo compounds. Examples of the radical polymerization initiator include ketone peroxides such as methyl ethyl ketone peroxide and methyl acetoacetate peroxide; 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis Peroxyketals such as (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane; permethane hydroper Hydroperoxides such as oxide, 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide; dicumyl peroxide, 2,5-dimethyl-2,5-di ( t-Butylperoxy) hexane α, α′-bis (t-butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxide) Dialkyl peroxides such as oxy) hexyne-3; diacyl peroxides such as benzoyl peroxide; peroxys such as di (3-methyl-3-methoxybutyl) peroxydicarbonate and di-2-methoxybutylperoxydicarbonate Dicarbonate: t-butyl peroxyoctate, t-butyl peroxyisobutyrate, t-butyl peroxylaurate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxy Isopropyl carbonate, 2,5-dimethyl-2,5-di (benzoylpa Oxy) hexane, t- butyl peroxy acetate, t- butyl peroxybenzoate, one or more organic peroxides such as peroxy esters such as di -t- butyl peroxy isophthalate and the like.

  Of these, those having a particularly high hydrogen abstraction ability are preferred. Examples of such radical polymerization initiators include 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1. Peroxyketals such as bis (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane; dicumyl Peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, di Dialkyl peroxides such as t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3; Diacyl peroxides such as nzoyl peroxide; t-butyl peroxyoctate, t-butyl peroxyisobutyrate, t-butyl peroxylaurate, t-butylperoxy-3,5,5-trimethylhexano Ate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, t-butylperoxybenzoate, di-t-butylperoxyiso 1 type, or 2 or more types, such as peroxyesters, such as a phthalate, is mention | raise | lifted.

  The addition amount of the radical polymerization initiator is preferably in the range of 0.01 to 10 parts by weight and more preferably in the range of 0.05 to 5 parts by weight with respect to 100 parts by weight of the polyolefin resin. preferable. If it is less than 0.01 part by weight, the modification does not proceed sufficiently, and if it exceeds 10 parts by weight, fluidity and mechanical properties may be lowered.

The present invention will be described in more detail below based on examples, but the present invention is not limited thereto.
(Residual volatile components)
A calibration curve was drawn by gas chromatography (GC-17A Shimadzu Corporation) and measured. HP No190952Z-623 (made by HP) was used for the column, and the density | concentration of the glycidyl methacrylate and styrene in 1g of pellets was measured.

Example 1
<Extrusion modification>
100 parts of homopolypropylene (manufactured by Prime Polymer Co., Ltd., J105G, MFR = 9) and 1,3-di (t-butylperoxyisobrovir) benzene (Nippon Yushi Co., Ltd .: Perbutyll P)
1 part half-life of 175 ° C) 0.5 parts by weight was mixed and fed from the popper port of a twin screw extruder (TEX44: L / D = 38, manufactured by Nippon Steel) set to 200 ° C and melted Thereafter, 5 parts by weight of glycidyl methacrylate and 5 parts by weight of styrene were added and kneaded from the addition port, and a modified polyolefin resin molded into a strand shape from the die was obtained. The resin discharge rate at this time was 50 kg / hr.

<Residual volatile component removal>
Subsequently, the strand-like modified polyolefin resin continuously melted is introduced into a strand cooling net conveyor (L3000 × W500 × H900, manufactured by Tanaka Co., Ltd.) so that the strand is vertical from the die to the net conveyor. It set to 20 m / min, and after injecting tap water showering at 10 L / min, it cut | disconnected with the pelletizer (made by KM-150H limited company Katsu Seisakusho). The residual volatile component of the pellet was 1559 ppm. The water temperature of showering at this time was 10 ° C.

(Comparative Example 1)
<Extrusion modification>
Extrusion modification was performed in the same manner as in Example 1. The resin discharge rate at this time was 50 kg / hr.

<Residual volatile component removal>
Subsequently, the strand-shaped modified polyolefin resin continuously melted is submerged in a cooling water tank (L3000 × W300 × H400) while being drawn (linear speed 23 m / min) with a pelletizer (KM-150H, manufactured by Katsu Manufacturing Co., Ltd.) Disconnected. The residual volatile component of the pellet was 18776 ppm. The cooling water tank internal temperature at this time was 10 degreeC.

  In Example 1 of the present invention, the amount of residual volatile components in the obtained pellet was greatly reduced as compared with the comparative example in which the melted strand was directly submerged in the cooling water tank. The present invention can avoid various problems that occur during forced exhaust of volatile components from a generally used extruder vent, and can greatly reduce the residual volatile content in the resulting pellets.

Claims (8)

  A method for reducing residual volatile components of a thermoplastic resin composition, wherein a strand-shaped thermoplastic resin composition and a cooling medium are brought into contact with each other.   The method for reducing residual volatile components of a thermoplastic resin composition according to claim 1, wherein after the molten resin extruded in a strand shape by the extruder is stretched in the take-up direction, the cooling medium is dispersed by showering.   The thermoplastic resin composition according to claim 1 or 2, wherein the showering cooling medium is water, and the amount of water is 50 L / min or less per 50 Kg / Hr of the extruded molten resin. Method for reducing residual volatile components.   The method for reducing residual volatile components of the thermoplastic resin composition according to any one of claims 1 to 3, wherein a temperature of the showering water is 50 ° C or lower.   The method for reducing residual volatile components in a thermoplastic resin composition according to any one of claims 1 to 4, wherein the thermoplastic resin polymerization composition is a modified polyolefin resin.   The modified polyolefin resin is obtained by melting and kneading a compound containing an ethylenic double bond and a polar group in the same molecule and an aromatic vinyl monomer in the presence of a radical polymerization initiator with respect to the polyolefin resin. The ethylenic double bond and the polar group in a total of 100% by weight of the polyolefin resin, the compound containing the ethylenic double bond and the polar group in the same molecule, the aromatic vinyl monomer and the other vinyl monomer. 6. The method for reducing residual volatile components of a thermoplastic resin composition according to claim 5, wherein the proportion of the compound contained in the same molecule is a modified polyolefin resin in the range of 0.05 to 50% by weight. .   The compound containing an ethylenic double bond and a polar group in the same molecule is at least one selected from the group consisting of an unsaturated carboxylic acid, its anhydride, its derivative, and an epoxy group-containing vinyl monomer. Item 7. A method for reducing residual volatile components of a thermoplastic resin composition according to Item 6.   The compound containing the ethylenic double bond and the polar group in the same molecule is at least one selected from the group consisting of (meth) acrylic acid, maleic anhydride, and glycidyl (meth) acrylate. The method for reducing residual volatile components as described.