Molding machine cleaning resin composition

Abstract

To provide a molding machine cleaning resin composition capable of exhibiting cleaning performance equal to or superior to conventional compositions and having excellent operability.SOLUTION: A molding machine cleaning resin composition of the present invention comprises an acrylonitrile-styrene copolymer (AS) resin, a rubber component, and an aliphatic surfactant and / or an aromatic surfactant, wherein the content of the rubber component is 3 to 15 pts.mass per 100 pts.mass of the AS resin. It is preferable that the content of structural units derived from a cyanovinyl compound in the AS resin is 34 mass% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a resin composition for cleaning molding machines. [Background technology]

[0002] Injection molding machines and extrusion molding machines are primarily used for molding thermoplastic resins. After use, these molding machines leave behind the resin, additives, and resin degradation products generated during molding. If the next resin is molded while the residue remains, the residue will be mixed into the molded product, degrading the appearance of the molded product and reducing the expected physical properties of the resin. Therefore, pellet-shaped cleaning agents are generally used before the next molding process (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-201975 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional cleaning agents such as those described in Patent Document 1 have a problem in that resin powder is generated when pellets come into contact with each other during pellet production or transportation. The generated resin powder reduces workability, so there has been a demand for reducing the resin powder and improving workability. Note that in this disclosure, resin powder refers to powdery resin that is generated when pellets collide with each other during transportation, etc.

[0005] The present disclosure is intended to solve the above-mentioned problems, and an object of the present disclosure is to provide a resin composition for cleaning molding machines that exhibits cleaning properties equal to or better than conventional ones and has excellent workability. [Means for solving the problem]

[0006] The inventors of the present disclosure have discovered that a resin composition for cleaning molding machines, which contains an acrylonitrile-styrene copolymer (AS) resin, a rubber component, and an aliphatic surfactant and / or an aromatic surfactant, in which the content of the rubber component is within a specific range and in which the amount of resin powder generated during production or transportation is a certain amount or less, exhibits cleaning performance equal to or better than conventional compositions while also having excellent workability.

[0007] That is, the present disclosure provides a resin composition for cleaning molding machines, which comprises an acrylonitrile-styrene copolymer (AS) resin, a rubber component, and an aliphatic surfactant and / or an aromatic surfactant, and the content of the rubber component is 3 to 15 parts by mass per 100 parts by mass of the AS resin.

[0008] The content of structural units derived from vinyl cyanide compounds in the AS resin is preferably 34% by mass or less, which makes it easier to suppress discoloration while maintaining an appropriate viscosity of the resin composition for cleaning molding machines.

[0009] The content of the aliphatic surfactant and the aromatic surfactant is preferably 0.5 to 10 parts by mass per 100 parts by mass of the AS resin. By being within this range, it is possible to easily exhibit the cleaning properties and self-draining properties of the resin, while also making it easier to prevent metering errors during injection molding. [Effects of the Invention]

[0010] The resin composition for cleaning molding machines according to the present disclosure exhibits cleaning properties equal to or better than conventional ones and is also excellent in workability. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Resin composition for cleaning molding machines] The resin composition for cleaning molding machines of the present disclosure (hereinafter, sometimes referred to as the "resin composition of the present disclosure") contains an acrylonitrile-styrene copolymer (AS) resin, a rubber component, and an aliphatic surfactant and / or an aromatic surfactant. The content of the rubber component is 3 to 15 parts by mass per 100 parts by mass of the AS resin, which sufficiently reduces the amount of resin powder and results in excellent workability.

[0012] When 1000 g of the resin composition of the present disclosure is placed in an antistatic polyethylene bag and manually shaken up and down and left and right a total of 100 times while the bag contains air, the amount of resin powder generated is 1 g or less, more preferably 0.7 g or less, and even more preferably 0.5 g or less. By keeping the amount of resin powder at 1 g or less, excellent workability can be achieved.

[0013] The amount of the resin composition of the present disclosure required to clean a PC / ABS resin, as measured under the conditions of the examples described below, is preferably 700 g or less, more preferably 600 g or less. When the amount of the resin composition required to clean a PC / ABS resin is 700 g or less, the resin can be efficiently discharged from the molding machine, and sufficient cleanability can be achieved.

[0014] Similarly, the amount required to wash the ABS resin, measured under the conditions of the Examples described below, is preferably 700 g or less, more preferably 600 g or less, and even more preferably 500 g or less. When the amount of resin composition required to wash the ABS resin is 700 g or less, the resin can be efficiently discharged from the molding machine, and sufficient washability can be achieved.

[0015] Furthermore, when the self-discharging property is evaluated under the conditions of the examples described below, the amount discharged is preferably within 400 g, more preferably within 350 g, and even more preferably within 300 g.

[0016] The resin composition of the present disclosure preferably has an MFR (melt flow rate) of 3 to 40 g / 10 min, more preferably 5 to 35 g / 10 min, and even more preferably 8 to 25 g / 10 min, as measured at a temperature of 240°C and a nominal load of 5 kg. When the MFR is 3 g / 10 min or more, the resin composition is likely to exhibit fluidity. When the MFR is 40 g / 10 min or less, the resin composition is likely to exhibit heat resistance and mechanical strength.

[0017] (Acrylonitrile-styrene copolymer (AS) resin) The resin composition of the present disclosure contains an acrylonitrile-styrene copolymer (AS) resin, preferably as a main component. The AS resin is a thermoplastic copolymer resin obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound. Only one type of AS resin may be used, or two or more types may be used.

[0018] Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile, with acrylonitrile being particularly preferred.

[0019] Examples of the aromatic vinyl compound include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, and tribromostyrene, with styrene and α-methylstyrene being particularly preferred.

[0020] The AS resin may contain, as a constituent monomer, a vinyl compound other than the vinyl cyanide compound and the aromatic vinyl compound. Examples of the other vinyl compounds include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; (meth)acrylic acids such as acrylic acid and methacrylic acid, and α,β-unsaturated carboxylic acids such as maleic anhydride; maleimides such as N-phenylmaleimide, N-methylmaleimide, and N-cyclohexylmaleimide; and glycidyl group-containing monomers such as glycidyl (meth)acrylate.

[0021] Specifically, the AS resin is preferably a copolymer resin containing acrylonitrile-derived structural units and styrene-derived structural units, and more preferably a copolymer resin consisting of acrylonitrile-derived structural units and styrene-derived structural units. That is, the AS resin is preferably an AS resin.

[0022] The intrinsic viscosity of the AS resin when dissolved in CHCl3 is not particularly limited, but is preferably 0.61 to 1.21, and more preferably 0.82 to 1.07. When the intrinsic viscosity is 0.61 or more, cleaning properties can be exhibited, and when it is 1.07 or less, self-draining properties can be improved.

[0023] The content of the vinyl cyanide compound-derived structural units in the AS resin is preferably 34% by mass or less, more preferably 31% by mass or less, and even more preferably 29% by mass or less, based on the total amount (100% by mass) of the AS resin. By ensuring that the content of the vinyl cyanide compound-derived structural units is 34% by mass or less, the viscosity of the AS resin can be kept appropriate while discoloration can be easily suppressed. While there is no particular lower limit, the content is preferably 22% by mass or more, and more preferably 23% by mass or more.

[0024] The AS-based resin preferably has an MFR (melt flow rate) of 9 to 70 g / 10 min, more preferably 15 to 40 g / 10 min, measured at a temperature of 220°C and a nominal load of 10 kg. An MFR of 9 g / 10 min or more tends to exhibit fluidity. Furthermore, an MFR of 70 g / 10 min or less tends to exhibit heat resistance and mechanical strength.

[0025] The content of the aromatic vinyl compound-derived structural units in the AS resin is preferably 66 to 78 mass %, more preferably 69 to 77 mass %, relative to the total amount (100 mass %) of the AS resin. When the content of the aromatic vinyl compound-derived structural units is within the above range, the viscosity of the AS resin can be kept appropriate and discoloration can be easily suppressed.

[0026] When the AS resin contains structural units derived from other vinyl compounds, the content thereof is preferably 10% by mass or less, more preferably 1% by mass or less, based on the total amount (100% by mass) of the AS resin. By keeping the content of structural units derived from other vinyl compounds at 10% by mass or less, the AS resin can more easily exhibit its functions.

[0027] The content of the AS resin is preferably more than 50% by mass, more preferably at least 70% by mass, even more preferably at least 80% by mass, and particularly preferably at least 90% by mass, of the total amount (100% by mass) of the resin composition of the present disclosure. When the content of the AS resin is more than 50% by mass, it can function as the main component of the resin composition of the present disclosure. While not particularly limited, the upper limit is preferably 97% by mass or less, more preferably 95% by mass or less.

[0028] The AS resin can be produced by known or commonly used methods, such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization.

[0029] (rubber component) The resin composition of the present disclosure contains a rubber component. By including the rubber component in the resin composition of the present disclosure, when the resin composition of the present disclosure is molded into pellets, the cross section of the pellets can be made smooth, and the amount of resin powder produced when the pellets come into contact with each other can be reduced. Only one type of rubber component may be used, or two or more types may be used.

[0030] As the rubber component, a rubber component alone may be used, or a rubber-containing resin may be used. Among these, it is preferable to use a rubber-containing resin from the viewpoint of exhibiting compatibility with the AS-based resin, etc., and it is more preferable that the rubber-containing resin is a styrene-based resin containing a rubber component. In the present disclosure, even if the resin contains a rubber component in part, such as the rubber-containing resin, the entire resin is treated as the rubber component.

[0031] Examples of the rubber component include diene rubber, urethane rubber, silicone rubber, polysulfide rubber, etc. Among these, diene rubber is preferred, and examples of the diene rubber include natural rubber, polyisoprene rubber, polybutadiene rubber, butyl rubber, chloroprene rubber, and modified rubber (epoxidized natural rubber, hydrogenated natural rubber, hydrogenated butadiene-acrylonitrile copolymer rubber, etc.).

[0032] In addition, examples of the rubber component contained in the rubber-containing resin include diene copolymers such as polybutadiene, polyisoprene, and random copolymers and block copolymers of styrene-butadiene, acrylonitrile-butadiene copolymers, and copolymers of (meth)acrylic acid alkyl esters and butadiene; copolymers of ethylene and α-olefins such as ethylene-propylene random copolymers and block copolymers, and ethylene-butene random copolymers and block copolymers; copolymers of ethylene and unsaturated carboxylic acid esters such as ethylene-methacrylate copolymers and ethylene-butyl acrylate copolymers; Examples of suitable rubbers include copolymers with aliphatic vinyls, ethylene-propylene-hexadiene copolymers and other non-conjugated diene polymers of ethylene, propylene, and acrylic rubbers such as polybutyl acrylate, poly(2-ethylhexyl acrylate), and copolymers of butyl acrylate and 2-ethylhexyl acrylate, as well as silicone rubbers such as polyorganosiloxane rubbers, IPN rubbers consisting of a polyorganosiloxane rubber component and a polyalkyl(meth)acrylate rubber component (i.e., rubbers in which the two rubber components are inseparably intertwined), and IPN rubbers consisting of a polyorganosiloxane rubber component and a polyisobutylene rubber component. Among these, polybutadiene, polyisoprene, and diene copolymers are preferred, with polybutadiene being particularly preferred.

[0033] Examples of the styrene-based resin containing the rubber component include HIPS resin, MS resin, ABS resin, AES resin, ASA resin, MBS resin, MABS resin, MAS resin, SMA resin, and styrene-based thermoplastic elastomer (e.g., (hydrogenated) styrene-butadiene-styrene copolymer, (hydrogenated) styrene-isoprene-styrene copolymer, etc.). Among these, ABS resin is preferred from the viewpoint of compatibility with the AS-based resin.

[0034] When a rubber-containing resin is included as the rubber component, the content of the rubber component in the total amount (100% by mass) of the rubber-containing resin is preferably 18 to 80% by mass, more preferably 35 to 70% by mass, and even more preferably 40 to 60% by mass. A rubber component content of 18% by mass or more facilitates reducing the amount of resin powder. Furthermore, a rubber component content of 80% by mass or less facilitates compatibility with other resin components included in the resin composition of the present disclosure.

[0035] Furthermore, when ABS resin is contained as the rubber component, the content of acrylonitrile-derived structural units in the total amount (100% by mass) of the ABS resin is preferably 28% by mass or less, more preferably 27% by mass or less, and even more preferably 26% by mass or less. By having the content of acrylonitrile-derived structural units be 28% by mass or less, discoloration of the ABS resin can be easily suppressed while maintaining a suitable viscosity. Furthermore, although there is no particular limitation on the lower limit, it is preferably 18% by mass or more, more preferably 23% by mass or more.

[0036] The content of the rubber component is 3 to 15 parts by mass, preferably 4 to 14 parts by mass, and more preferably 5 to 10 parts by mass, per 100 parts by mass of the AS resin. By including 3 parts by mass or more of the rubber component, the amount of resin powder can be reduced. Furthermore, by including 15 parts by mass or less, cleanability can be maintained.

[0037] The content of the rubber component in the total amount (100% by mass) of the resin composition of the present disclosure is preferably 2 to 13% by mass, and more preferably 3 to 12% by mass. By including 2% or more by mass of the rubber component, the amount of resin powder can be reduced. By including 12% or less by mass, cleanability can be maintained.

[0038] Furthermore, when the rubber component contains an ABS resin, the reduced viscosity of the ABS resin is preferably 0.2 to 0.8%, more preferably 0.3 to 0.7%, and even more preferably 0.4 to 0.6%.

[0039] The reduced viscosity was measured at 30°C after dissolving the ABS resin in acetone, separating it into an acetone-soluble fraction and an acetone-insoluble fraction, volatilizing the acetone from the acetone-soluble fraction, and dissolving the resulting fraction in dimethylformamide to prepare a 0.4 g / 100 ml solution.

[0040] (Aliphatic surfactants and / or aromatic surfactants) The resin composition of the present disclosure contains an aliphatic surfactant and / or an aromatic surfactant. The surfactant is a component added to the resin composition of the present disclosure to enhance its cleaning properties and to exhibit self-draining properties. As the aliphatic surfactant and / or the aromatic surfactant, either one may be used alone, or two or more of each may be used. Furthermore, the aliphatic surfactant and the aromatic surfactant may each be used alone, or two or more of each may be used.

[0041] Examples of the aliphatic surfactant include nonionic aliphatic surfactants and anionic aliphatic surfactants.

[0042] Examples of the nonionic aliphatic surfactants include sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyalkylene alkyl ethers, and polyoxyalkylene fatty acid esters.

[0043] Examples of the sorbitan fatty acid esters include sorbitan monooleate, sorbitan monostearate, sorbitan monoisostearate, sorbitan monopalmitate, sorbitan monolaurate, sorbitan trioleate, sorbitan tristearate, sorbitan sesquistearate, sorbitan sesquioleate, sorbitan sesquiisostearate, and sorbitan coconut oil fatty acid. Examples of alkylene oxide adducts of sorbitan fatty acid esters include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monoisostearate, polyoxyethylene sorbitan monococonut oil fatty acid, polyoxyethylene sorbitan tristearate, and polyoxyethylene sorbitan trioleate.

[0044] The glycerin fatty acid esters include both monoglycerin fatty acid esters and polyglycerin fatty acid esters. Examples of monoglycerin fatty acid esters include glyceryl monocaprylate, glyceryl monocaprate, glyceryl monolaurate, glyceryl monomyristate, glyceryl monopalmitate, glyceryl monostearate, glyceryl monoisostearate, glyceryl monobehenate, glyceryl monooleate, glyceryl monoerucate, glyceryl sesquioleate, glyceryl distearate, glyceryl diisostearate, and glyceryl diarachate. Examples of the polyglycerol fatty acid esters include polyglycerol fatty acid esters of the above monoglycerol fatty acid esters having a degree of polymerization of 2 to 10, such as diglyceryl monocaprylate, decaglyceryl monocaprylate, hexaglyceryl monocaprate, tetraglyceryl monolaurate, hexaglyceryl monolaurate, decaglyceryl monolaurate, poly(4-10)glyceryl monolaurate, decaglyceryl monomyristate, decaglyceryl monostearate, decaglyceryl monoisostearate, poly(2-10)glyceryl monostearate, diglyceryl monooleate, hexaglyceryl monooleate, diglyceryl sesquioleate, poly(2-10)glyceryl diisostearate, poly(6-10)glyceryl distearate, diglyceryl triisostearate, and poly(10)glyceryl tristearate. Examples of alkylene oxide adducts of glycerin fatty acid esters include polyoxyethylene glyceryl monostearate and polyoxyethylene glyceryl monooleate.

[0045] The polyoxyalkylene alkyl ethers include both monooxyalkylene alkyl ethers and polyoxyalkylene alkyl ethers, such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene polyoxypropylene lauryl ether, polyoxypropylene cetyl ether, polyoxypropylene isocetyl ether, polyoxypropylene stearyl ether, and polyoxypropylene oleyl ether.

[0046] The polyoxyalkylene fatty acid esters include both monooxyalkylene fatty acid esters and polyoxyalkylene fatty acid esters, and specific examples of the polyoxyalkylene fatty acid esters include ethylene glycol mono- and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol mono- and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, and polypropylene glycol mono- and di-fatty acid esters.

[0047] Specific examples of the ethylene glycol mono- and di-fatty acid esters include ethylene glycol monolaurate, ethylene glycol monopalmitate, ethylene glycol monostearate, ethylene glycol dilaurate, ethylene glycol dipalmitate, ethylene glycol distearate, etc. Of these, ethylene glycol distearate is more preferred.

[0048] Examples of the anionic aliphatic surfactants include alkyl or alkenyl ether sulfates, alkyl or alkenyl sulfates, α-olefin sulfonates having 8 to 20 carbon atoms, alkanesulfonates, alkyl or alkenyl ether carboxylates, and alkali metal salts of saturated or unsaturated fatty acids having 12 to 20 carbon atoms. Among these, alkanesulfonates are preferred.

[0049] Examples of the alkanesulfonates include sodium octyl sulfonate, sodium ethylhexyl sulfonate, sodium undecyl sulfonate, sodium dodecyl sulfonate, sodium dodecyl sulfonate, sodium hexadecyl sulfonate, and sodium octadecyl sulfonate. The salt may be a potassium salt, an ammonium salt, or the like, in addition to a sodium salt. Among these, the alkanesulfonate is preferably a sodium alkanesulfonate, and more preferably a mixture of sodium alkanesulfonates having 10 to 18 carbon atoms.

[0050] The content of the aliphatic surfactant is preferably 50 to 90% by mass, more preferably 55 to 85% by mass, and even more preferably 60 to 70% by mass, relative to the total amount of surfactants used (100% by mass). When the content of the aliphatic surfactant relative to the total amount of surfactants is within the above range, it becomes easy to exhibit cleaning properties against various resins.

[0051] The content of the aliphatic surfactant is preferably 0.5 to 10 mass %, and more preferably 2 to 8 mass %, relative to the total amount (100 mass %) of the resin composition of the present disclosure.

[0052] Examples of the aromatic surfactant include nonionic aromatic surfactants and anionic aromatic surfactants.

[0053] Examples of the nonionic aromatic surfactants include polyoxyethylene bisphenol A ether, polyoxyethylene bisphenol F ether, polyoxypolycyclic phenyl ether, polyoxyethylene phenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene cumyl phenyl ether, polyoxyethylene tribenzyl phenyl ether, and polyoxyethylene benzyl ether.

[0054] Examples of the anionic aromatic surfactant include alkylbenzene sulfonates and aromatic condensed phosphate esters, and aromatic condensed phosphate esters are particularly preferred.

[0055] As the alkylbenzenesulfonate, for example, a linear alkylbenzenesulfonate having an alkyl group with 8 to 20 carbon atoms or less can be used, and specific examples thereof include sodium decylbenzenesulfonate, sodium undecylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium tridecylbenzenesulfonate, sodium tetradecylbenzenesulfonate, sodium pentadecylbenzenesulfonate, sodium hexadecylbenzenesulfonate, etc. The salt may be a potassium salt, an ammonium salt, or the like, in addition to a sodium salt.

[0056] Examples of the aromatic condensed phosphate ester include resorcinol bisdiphenyl phosphate, bisphenol A bis(diphenyl phosphate), and resorcinol bisdixylenyl phosphate, with resorcinol bisdixylenyl phosphate being preferred.

[0057] The content of the aromatic surfactant is preferably 10 to 50 mass % relative to the total amount (100 mass %) of the surfactants used, more preferably 15 to 45 mass %, and even more preferably 20 to 40 mass %. When the content of the aromatic surfactant relative to the total amount of surfactants is within the above range, it becomes easy to exhibit cleaning properties against various resins.

[0058] The content of the aromatic surfactant is preferably 0.5 to 5 mass %, and more preferably 1 to 4 mass %, relative to the total amount (100 mass %) of the resin composition of the present disclosure.

[0059] The total content of the aliphatic surfactant and the aromatic surfactant is preferably 0.5 to 10 mass %, more preferably 1 to 9 mass %, and even more preferably 3 to 8 mass %, relative to the total amount (100 mass %) of the resin composition of the present disclosure. When the content of the aliphatic surfactant and the aromatic surfactant is 0.5 mass % or more, the resin can be easily cleaned and self-draining. Furthermore, when the content is 10 mass % or less, metering errors during injection molding can be easily prevented. When the resin composition of the present disclosure contains only one of the aliphatic surfactant and the aromatic surfactant, the content thereof preferably satisfies the above range.

[0060] The resin composition of the present disclosure preferably contains an inorganic filler. By containing the inorganic filler, the viscosity of the resin composition of the present disclosure can be adjusted while the cleaning properties can be exhibited due to the polishing effect of the inorganic filler. Only one type of the inorganic filler may be used, or two or more types may be used.

[0061] The inorganic filler may be either a natural product or an artificially synthesized product, and examples of the inorganic filler include talc, mica, wollastonite, xonotlite, kaolin clay, montmorillonite, bentonite, sepiolite, imogolite, sericite, lawsonite, smectite, calcium carbonate, magnesium carbonate, titanium oxide, aluminum hydroxide, magnesium hydroxide, zeolite, diatomaceous earth, glass powder, glass spheres, and shirasu balloons.

[0062] The shape of the inorganic filler is not particularly limited and may be any shape (plate-like, needle-like, granular, fibrous, etc.). These inorganic fillers may also be fired or may have been subjected to a surface hydrophobic treatment using a silane coupling agent, titanate coupling agent, or the like. Furthermore, the volume-average particle size is preferably 0.1 to 50 μm, more preferably 1 to 30 μm. The volume-average particle size can be measured by a laser diffraction scattering method.

[0063] The content of the inorganic filler is preferably 0.1 to 10 mass% and more preferably 0.5 to 5 mass% relative to the total amount (100 mass%) of the resin composition of the present disclosure. By setting the content of the inorganic filler to 0.1 mass% or more, it becomes easy to improve the cleanability. Furthermore, by setting the content to 10 mass% or less, it becomes easy to adjust the viscosity of the resin composition of the present disclosure to an appropriate level.

[0064] Furthermore, it is preferable that the resin composition of the present disclosure further contains a phosphate and / or a condensed phosphate. By containing a phosphate and / or a condensed phosphate, the cleaning properties and replacement properties can be further improved. As the phosphate and / or the condensed phosphate, only one kind of either one may be used, or two or more kinds of either one may be used. Furthermore, the phosphate and the condensed phosphate may each be used alone, or two or more kinds may be used.

[0065] Examples of the phosphate salt include sodium phosphate and disodium hydrogen phosphate.

[0066] Examples of the condensed phosphate include sodium pyrophosphates such as disodium dihydrogen pyrophosphate and sodium dihydrogen pyrophosphate, sodium tripolyphosphate, sodium tetrapolyphosphate, sodium pentapolyphosphate, and sodium metaphosphate.

[0067] The content of the phosphate and the condensed phosphate is preferably 0.1 to 10 mass %, more preferably 0.5 to 5 mass %, relative to the total amount (100 mass %) of the resin composition of the present disclosure. When the content of the phosphate and the condensed phosphate is within the above range, cleaning properties and replacement properties can be easily exhibited.

[0068] The resin composition of the present disclosure may contain other components in addition to the above-mentioned components. Examples of the other components include flame retardants, anti-dripping agents, dyes and pigments, heat stabilizers, UV absorbers, fluorescent brighteners, lubricants, processing aids, dispersants, mold release agents, thickeners, antioxidants, antistatic agents, and foaming agents. Only one type of the other components may be used, or two or more types may be used.

[0069] The content of the other components is preferably 10% by mass or less, more preferably 5% by mass or less, and may be 0% by mass, relative to the total amount (100% by mass) of the resin composition of the present disclosure.

[0070] The method for producing the resin composition of the present disclosure is not particularly limited, but a preferred production method includes a process comprising melt-kneading the AS resin, the rubber component, the surfactant, and the phosphate, condensed phosphate, inorganic filler, and other components that are blended as needed using a melt-kneading device such as a kneader, extruder, or Banbury mixer, extruding the resulting melt-kneaded mixture into strands, and then molding them into pellets. The melt-kneading device is preferably an extruder, as it can sufficiently knead raw materials such as thermoplastic resins.

[0071] When blending and melt-kneading the components, commonly used devices can be used, for example, premixers such as tumblers, ribbon blenders, and supermixers, and melt-kneading devices such as gravimetric feeders, single-screw extruders, twin-screw extruders, and co-kneaders. When melt-kneading, it is desirable to perform open devolatilization, in which devolatilized material is removed from an open port (vent) at normal pressure, and, if necessary, reduced-pressure devolatilization, in which devolatilized material is removed from an open port (vent) by reducing the pressure.

[0072] The temperature in the step of pelletizing the strands into pellets is preferably 40 to 150° C., more preferably 50 to 120° C. Even when the resin composition of the present disclosure is rapidly cooled, it can be molded to have a smooth cross section, thereby reducing resin powder generated by pellets rubbing against each other.

[0073] A method for cleaning a molding machine using the resin composition of the present disclosure includes charging the resin composition of the present disclosure into the cylinder of a resin molding machine, heating the resin composition of the present disclosure to plasticize (melt) and maintain it, and then discharging the plasticized resin composition of the present disclosure from the cylinder of the resin molding machine. In particular, the resin composition of the present disclosure has a reduced amount of resin powder, which makes it easier to charge into the cylinder.

[0074] Applicable resin molding machines include, for example, injection molding machines and extrusion molding machines, but are not particularly limited to these as long as they have a cylinder for heating, melting, and kneading the resin. That is, the resin composition of the present disclosure can be widely applied to known resin molding machines. When heating the resin composition of the present disclosure, the cylinder temperature of the resin molding machine is preferably 180°C or higher, more preferably 200°C or higher. The upper limit of the heating temperature is not particularly limited, but is usually about 400°C.

[0075] The resin composition of the present disclosure can efficiently clean and discharge residual resin materials contained in the resin itself or in molding materials such as dyes and pigments that remain in the molding machine after a predetermined operation in the extruder molding machine or injection molding machine, and therefore can be suitably used as a cleaning resin composition for cleaning the inside of a thermoplastic resin molding machine. That is, the resin composition of the present disclosure is preferably a cleaner for an extruder molding machine or an injection molding machine.

[0076] Furthermore, the resin composition of the present disclosure can be suitably used for resins to be cleaned, such as PA, PMMA, PLA, ABS, AS, PVC, PVDF, TPU, PC, PET, PBT, and POM, as well as resin compositions containing any of the above resins as a main component (preferably 50% by mass or more).

[0077] Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Each configuration and combination thereof in each embodiment is an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate within the scope of the present disclosure. Furthermore, each invention according to this disclosure is not limited by the embodiments or the following examples, but is limited only by the scope of the claims. [Example]

[0078] Hereinafter, one embodiment of the present disclosure will be described in more detail based on examples.

[0079] Examples 1 to 3, Comparative Examples 1 to 2 The components shown in Table 1 were mixed in a tumbler blender (product name "SFC-50", manufactured by Kawata Corporation) (mixing time: 120 seconds, mixing speed: 120 rpm), and then molded into pellets using an extruder (product name "TEX-30", manufactured by The Japan Steel Works, Ltd.) under the following conditions: nozzle diameter: 32 mm, cylinder temperatures C1: 210°C, C2 to C8: 230°C (C1: upstream, C8: downstream), die temperature: 240°C, screw rotation speed: 200 rpm, and discharge rate: 20 kg / h, to produce resin compositions for cleaning molding machines of Examples 1 to 3 and Comparative Examples 1 and 2. The MFRs of the resin compositions for cleaning molding machines in Example 1, Example 2, and Example 3, measured at a temperature of 240°C and a nominal load of 5 kg, were 13 g / 10 min, 15 g / 10 min, and 18 g / 10 min, respectively. The MFRs of the resin compositions for cleaning molding machines in Comparative Example 1 and Comparative Example 2 were 25 g / 10 min and 8.0 g / 10 min, respectively.

[0080] Each component used in Table 1 is described in detail below. Styrene-acrylonitrile copolymer: Content of structural units derived from vinyl cyanide compounds: 28% by mass, MFR (measurement temperature 220°C, nominal load 10 kg): 9.7 g / 10 min, intrinsic viscosity: 1.07 Styrene-acrylonitrile-butadiene copolymer: 45% by mass of structural units derived from aromatic vinyl compounds, 15% by mass of structural units derived from vinyl cyanide compounds, 40% by mass of structural units derived from rubber components, acetone solubles reduced viscosity 0.5%, intrinsic viscosity: 0.45 Sodium alkanesulfonate: (trade name "WeyClean SAS93", manufactured by Clariant Japan) Sodium dodecylbenzenesulfonate: (trade name "Neurex Soft 60-N", manufactured by NOF Corporation) Ethylene glycol distearate: (trade name "Emanon 3201M-V", manufactured by Kao Corporation) Aromatic condensed phosphate ester: (Product name "PX-200", manufactured by Daihachi Chemical Industry Co., Ltd.) Sodium phosphate: (trade name "disodium phosphate (anhydrous)", manufactured by Taihei Chemical Industry Co., Ltd.) Talc: (product name "Talc FU-51", manufactured by Hayashi Kasei Co., Ltd.)

[0081] [evaluation] The resin compositions for cleaning molding machines prepared in the Examples and Comparative Examples were evaluated as follows, and the results are shown in Table 1.

[0082] (1) Amount of resin powder generated 1000 g of each of the resin compositions for cleaning molding machines of Examples 1 to 3 and Comparative Examples 1 and 2 was placed in an antistatic polyethylene bag, and the bag was stirred by manually shaking it up and down and left and right a total of 100 times while the bag contained air. After that, the entire contents of the antistatic polyethylene bag was passed through a 4.0 mm sieve, and the amount (g) of resin powder sieved out was measured.

[0083] (2)-1. Cleaning ability for PC / ABS First, 500 g of PC / ABS resin (trade name "Novalloy S1100", manufactured by Daicel Miraize Co., Ltd.) was placed into an injection molding machine (trade name "2000i-100B", manufactured by Fanuc Corporation, injection speed 100 mm / sec, rotation speed 100 rpm, nozzle temperature 260°C - cylinder front 270°C - cylinder middle 260°C - cylinder rear 250°C, back pressure 0.3 MPa, stroke 50 mm) and then ejected.

[0084] Next, the stroke was adjusted to 40 mm, and 100 g of each of the resin compositions for cleaning molding machines of Examples 1 to 3 and Comparative Examples 1 and 2 was added to the injection molding machine, up to a maximum of 1000 g, to replace the PC / ABS resin. The cleaning was considered complete when the color of the PC / ABS resin was no longer visible to the naked eye, and the mass (g) of the cleaning resin composition required to complete the cleaning was measured.

[0085] (2)-2. Cleanability for ABS The cleaning ability for ABS resin was measured in the same manner as in (2)-1, except that black ABS resin pellets (product name "Cevian V 500" manufactured by Daicel Miraize Co., Ltd.) were used instead of PC / ABS resin (product name "Novalloy S1100" manufactured by Daicel Miraize Co., Ltd.) and the nozzle temperature of the injection molding machine was set to 220°C, 230°C at the front of the cylinder, 220°C at the middle of the cylinder, and 210°C at the rear of the cylinder.

[0086] (3) Self-evacuation The resin compositions for cleaning molding machines of Examples 1 to 3 and Comparative Examples 1 and 2 were discharged under the same conditions as those used to evaluate the cleaning ability for ABS described above, and then injection molding was performed using a transparent AS resin (product name "Cevian 050SF", manufactured by Daicel Miraize Co., Ltd.) at a cylinder temperature of 230°C. If no residue was found within 400 g, the composition was evaluated as "Good," and if any residue remained even after using more than 400 g, the composition was evaluated as "Poor."

[0087] [Table 1]

[0088] The resin compositions for cleaning molding machines of Examples 1 to 3 have cleaning properties equal to or better than conventional products, It was confirmed that the amount of resin powder was reduced and workability was excellent. On the other hand, when no rubber component was contained, a large amount of resin powder was generated and workability was poor (Comparative Example 1). Furthermore, when the rubber component was contained in excess relative to the AS-based resin, it was confirmed that cleanability was poor (Comparative Example 2).

Claims

1. The composition comprises an acrylonitrile-styrene copolymer (AS) resin, a rubber component, and an aliphatic surfactant and / or an aromatic surfactant, The resin composition for cleaning molding machines has a rubber component content of 3 to 15 parts by mass per 100 parts by mass of the AS-based resin.

2. 2. The resin composition for cleaning molding machines according to claim 1, wherein the AS-based resin contains structural units derived from vinyl cyanide compounds in an amount of 34% by mass or less.

3. 3. The resin composition for cleaning molding machines according to claim 1, wherein the amount of the aliphatic surfactant and the aromatic surfactant is 0.5 to 10 parts by mass per 100 parts by mass of the AS-based resin.

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