Resin components for cleaning casting equipment.

Abstract

Invention details;

Description

Resin composition for cleaning molding machines

[0001] The present invention relates to a resin composition for cleaning a molding machine.

[0002] Resin molding machines, such as extruders and injection molding machines, are commonly used for resin coloring, mixing, molding, and other operations. However, these machines often leave residues in the molding machine after a given operation, including the resin itself, additives such as dyes and pigments contained in the molding material, and degraded materials (e.g., pyrolysis products, char, and carbides) generated from the resin. If these residues are left unattended, they can be mixed into molded products during subsequent molding operations, resulting in poor product appearance. In particular, when molding transparent resins, even minute amounts of carbides and other contaminants are easily visible, resulting in poor product appearance and an increased incidence of defective molded products. Therefore, it is desirable to completely remove these residues from the molding machine.

[0003] Conventionally, methods for removing residues from molding machines have been adopted, including (1) manually disassembling and cleaning the molding machine; (2) filling the molding machine with the molding material to be used for the next molding without shutting down the molding machine, thereby gradually discharging the residues; and (3) using a cleaning agent. Method (1) is inefficient because it requires shutting down the molding machine, and the manual physical removal work is likely to damage the molding machine. Method (2) often requires a large amount of molding material to remove the residues, which takes time to complete and generates a large amount of waste. Therefore, in recent years, method (3) using a cleaning agent has become popular because of its excellent cleaning power for removing residues from molding machines. Method (3) using a cleaning agent also has the problem that the degree of cleaning is likely to vary depending on the experience and skill of the worker, and the cleaning work itself is a burden on the worker. Therefore, in recent years, molding machines have been equipped with a function called metering purge or auto-purge (hereinafter referred to as metering purge) that automatically repeats metered injection, and this function is often used in the cleaning process. The metering purge is becoming more popular because it promotes and uniforms the cleaning effect without relying on the experience or skill of the operator, and is an easy-to-use cleaning process.

[0004] Techniques for improving the cleaning power of cleaning agents have been proposed with the aim of enhancing their effectiveness. For example, Patent Document 1 describes a cleaning granule mixture containing at least two types of granules with different melt flow rates and a lubricant, and is described as a composition having excellent cleaning power and efficient substitution for a subsequent resin composition. Patent Document 2 describes a cleaning resin composition containing a thermoplastic resin, a polypropylene resin, and an inorganic filler, and is described as having excellent cleaning effect and workability. Patent Document 3 describes a cleaning resin composition containing a styrene-based resin, a polyalkylene oxide glycol, an alkyl sulfate, and an aliphatic metal salt, and is described as having excellent cleaning power for a previous material and excellent substitution for a subsequent material. Patent Document 4 describes a cleaning composition for molding machines consisting of a thermoplastic resin, an inorganic filler, and a lubricant, and is described as having excellent cleaning power. Patent Document 5 describes a cleaning agent for resin molding machines containing a polyolefin resin, an inorganic filler, a surfactant, a polar functional group-containing polyolefin wax, and a fatty acid metal salt, and describes that the cleaning agent has excellent cleaning properties for colorants such as dyes and pigments and also has excellent penetration into resin molding machines. Patent Document 6 describes a cleaning agent for molding machines containing a polypropylene resin and a surfactant, and describes that the cleaning agent has excellent cleaning properties for molding machines and excellent removability of compositions remaining after cleaning.

[0005] Japanese Patent Application Laid-Open No. 2007-246626 Japanese Patent Application Laid-Open No. 2017-218540 International Publication No. 00 / 056514 Japanese Patent Application Laid-Open No. 6-134770 Japanese Patent Application Laid-Open No. 59-124999 Japanese Patent Application Laid-Open No. 2018-69473 Japanese Patent Application Laid-Open No. 2010-95625

[0006] However, the inventors' investigations revealed that the cleaning performance of the cleaning agents described in Patent Documents 1 to 7 was insufficient, resulting in the problem of requiring a large amount of resin to replace the molding material used in the previous molding with the cleaning agent and to replace the cleaning agent with the molding material used in the next molding. Furthermore, when cleaning engineering plastics and other materials whose molding machine is set at a relatively high temperature, the cleaning resin composition cannot be supplied from the raw material hopper to the inside of the cylinder of the molding machine, resulting in poor material biting and long metering times, or metering failures that make metering purging impossible. Furthermore, when highly heat-resistant materials are cleaned at high temperatures, the cleaning performance is insufficient, resulting in the problem of requiring a large amount of resin and time to replace the molding material used in the previous molding with the cleaning agent and to replace the cleaning agent with the molding material used in the next molding. Furthermore, when the lubricants and surfactants described in Patent Documents 2, 4, 5, and 6 are incorporated, there are workability issues, such as the risk of burns and smoke due to the cleaning agent being ejected from the molding machine during the cleaning process.

[0007] Therefore, cleaning chemicals must have high cleaning power for materials that have been molded before cleaning, be easily replaceable with materials to be molded after cleaning, have stable material-biting properties regardless of the cleaning temperature, be compatible with metered purging, and be safe to use by reducing the risk of burns and smoke caused by spraying.

[0008] Therefore, an object of the present invention is to provide a resin composition for cleaning molding machines that combines high cleaning power for materials that have been molded before cleaning, regardless of the cleaning temperature, with easy replacement for materials that will be molded after cleaning, has stable raw material biting properties, is compatible with metered purging, and suppresses spraying and smoke from the molding machine during cleaning operations, thereby improving workability.

[0009] As a result of extensive research to solve the above problems, the inventors of the present invention have focused on the rheological properties of thermoplastic resins and synthetic waxes and have found that by using a specific resin composition, it is possible to achieve high cleaning power for materials that have been molded before cleaning, and that the cleaning resin composition does not remain in the molding machine, allowing it to easily replace the material to be molded after cleaning, and that it is possible to improve workability by suppressing spraying and smoke from the molding machine during cleaning.Furthermore, with regard to the ability to bite raw materials, the inventors have found that by blending a specific thermoplastic resin, it is possible to improve the ability of the raw materials to be bitten from the raw material hopper into the cylinder, leading to the development of the present invention.

[0010] That is, the present invention is as follows: [1] A composition comprising at least a thermoplastic resin (A), a synthetic wax (B), and a polyolefin resin (C), wherein the solubility parameter δ of the thermoplastic resin (A) is （Ａ） and the solubility parameter δ of the synthetic wax (B) （Ｂ） The absolute value of the difference is 2.0 (cal / cm ３ ) １／２ More than 7.0 (cal / cm ３ ) １／２ a resin composition for cleaning molding machines, the resin composition comprising: a blending amount of the polyolefin resin (C) being more than 0.1% by mass but less than 10% by mass; and a glass transition point of the polyolefin resin (C) being more than -150°C but less than 40°C; [2] The resin composition for cleaning molding machines according to [1], wherein the synthetic wax (A) is a polycarbonate resin; [3] The resin composition for cleaning molding machines according to [1] or [2], wherein the synthetic wax (B) is a homopolymer polyethylene wax or a homopolymer polypropylene wax; [4] The resin composition for cleaning molding machines according to any one of [1] to [3], wherein the weight-average molecular weight of the synthetic wax (B) is 1,000 to 50,000; [5] The resin composition for cleaning molding machines according to any one of [1] to [4], wherein the content of the synthetic wax (B) is 0.1 to 20% by mass; [6] The solubility parameter δ of the thermoplastic resin (A) is （Ａ） and the solubility parameter δ of the synthetic wax (B). （Ｂ） and the solubility parameter δ of the olefin-based resin (C). （Ｃ） The relationship between（Ａ） >δ （Ｃ） ≧δ （Ｂ） [7] The resin composition for cleaning a molding machine according to any one of [1] to [5], wherein the solubility parameter δ of the thermoplastic resin (A) is （Ａ） and the solubility parameter δ of the polyolefin resin (C) （ C ） The absolute value of the difference is 2.0 (cal / cm ３ ) １／２ Above, 7.0 (cal / cm ３ ) １／２ The resin composition for cleaning a molding machine according to any one of [1] to [6], wherein the sliding velocity V ｓ (mm / s) and true shear stress τ ｃｏｒｒｅｃｔ [9] The resin composition for cleaning molding machines according to any one of [1] to [8], wherein the slope α obtained from a linear approximation line of a scatter diagram in which the pressure (kPa) of the resin composition is plotted is 0.10 mm / (s·kPa) or more.

[10] The resin composition for cleaning molding machines according to any one of [1] to [9], wherein the water content measured by the Karl Fischer method is 5000 ppm or less.

[11] The resin composition for cleaning molding machines according to any one of [1] to [9], wherein the rate of weight loss on heating at 300°C is 3% by mass or less.

[0011] According to the present invention, it is possible to provide a resin composition for cleaning a molding machine which has both high cleaning power for materials that have been molded before cleaning, regardless of the cleaning temperature, and easy replacement for materials that will be molded after cleaning, and which suppresses spraying and smoke from the molding machine during cleaning, improving workability, and which is also suitable for raw material biting and metered purging.

[0012] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the present invention is not limited to the present embodiment described below, and various modifications can be made within the scope of the gist of the present invention.

[0013] [Resin composition for cleaning molding machines] The resin composition for cleaning molding machines of the present embodiment (hereinafter also referred to as "cleaning resin composition") contains at least a thermoplastic resin (A), a synthetic wax (B), and a polyolefin resin (C), and the solubility parameter δ of the thermoplastic resin (A) is（Ａ） and the solubility parameter δ of the synthetic wax (B) （Ｂ） The absolute value of the difference is 2.0 (cal / cm ３ ) １／２ More than 7.0 (cal / cm ３ ) １／２ or less, and the blending amount of the polyolefin resin (C) is more than 0.1% by mass and less than 10% by mass.

[0014] (Thermoplastic resin (A)) The thermoplastic resin (A) used in this embodiment is a thermoplastic resin used in general injection molding, extrusion molding, etc., and the solubility parameter δ of the thermoplastic resin (A) is （Ａ） and the solubility parameter δ of the synthetic wax (B) described later. （Ｂ） The absolute value of the difference between （Ａ） -δ （Ｂ） |) is 2.0 (cal / cm ３ ) １／２ A wide range of resins can be used as long as they satisfy the above requirements, and two or more resins can also be used at the same time.

[0015] Specific examples of the thermoplastic resin (A) include styrene-based resins such as polystyrene, polyethylene-based resins such as polyethylene, polypropylene-based resins such as polypropylene, polyolefin-based resins such as polybutene-based resins such as polybutene, methacrylate-based resins such as polymethyl methacrylate, polyvinyl chloride, polyamide-based resins, polyester-based resins, polycarbonate-based resins, etc. Among these, styrene-based resins and polyester-based resins are preferred.

[0016] The styrene-based resin refers to polystyrene or a copolymer of styrene and one or more other monomers, with a styrene content of 50% by mass or more. Examples of other monomers to be copolymerized with styrene include acrylonitrile and butadiene. Specific examples of this styrene-based resin include polystyrene, styrene-acrylonitrile copolymer, and styrene-butadiene-acrylonitrile copolymer. Among these, styrene and styrene-acrylonitrile copolymer are preferred, and styrene-acrylonitrile copolymers with an acrylonitrile content of 5% by mass or more but less than 50% by mass are particularly preferred because of their excellent detergency for materials molded before washing and their ease of substitution for materials to be molded after washing.

[0017] Examples of the methacrylic acid ester resin include polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, and polybutyl methacrylate.

[0018] Examples of the polyamide resin include aliphatic polyamides such as polyamide 4 (poly-α-pyrrolidone), polyamide 6 (polycaproamide), polyamide 11 (polyundecaneamide), polyamide 12 (polydodecanamide), polyamide 46 (polytetramethylene adipamide), polyamide 66 (polyhexamethylene adipamide), polyamide 610, and polyamide 612; semi-aromatic polyamides such as polyamide 6T (polyhexamethylene terephthalamide), polyamide 9T (polynonamethylene terephthalamide), and polyamide 6I (polyhexamethylene isophthalamide); and copolymer polyamides containing these as constituent components. Examples of copolymerized polyamides include, but are not limited to, a copolymer of hexamethylene adipamide and hexamethylene terephthalamide, a copolymer of hexamethylene adipamide and hexamethylene isophthalamide, and a copolymer of hexamethylene terephthalamide and 2-methylpentanediamine terephthalamide.

[0019] The polyester resin is a copolymer having an ester bond in the repeating unit of the main chain, and polyethylene terephthalate obtained by polycondensation of terephthalic acid and ethylene glycol is preferably used. The polycarbonate resin is a copolymer having a carbonate bond in the repeating unit of the main chain, and examples thereof include copolymers obtained by a method of reacting an aromatic dihydroxy compound with a carbonate precursor, an interfacial polymerization method (e.g., the phosgene method) in which an aromatic dihydroxy compound is reacted with a carbonate precursor (e.g., phosgene) in the presence of an aqueous sodium hydroxide solution and methylene chloride solvent, an ester exchange method (melt method) in which an aromatic dihydroxy compound is reacted with a carbonate diester (e.g., diphenyl carbonate), or a method of solid-phase polymerization of a crystallized carbonate prepolymer obtained by the phosgene method or melt method. Polycarbonate resins are suitable because they exhibit high detergency when cleaning highly heat-resistant materials such as super engineering plastics at high temperatures (e.g., 300°C or higher).

[0020] The weight-average molecular weight of the thermoplastic resin (A) is not particularly limited, but is preferably 100,000 to 400,000, more preferably 110,000 to 350,000, and even more preferably 120,000 to 300,000. In this embodiment, the weight-average molecular weight is a value measured by gel permeation chromatography (GPC) or other methods. Specifically, the weight-average molecular weight can be measured, for example, by the qualitative and quantitative analysis methods described in the Examples below, or by other methods.

[0021] The melt flow rate (MFR) of the thermoplastic resin (A) is preferably 0.5 g / 10 min or more from the viewpoint of ease of use, more preferably 40 g / 10 min or less from the viewpoint of cleaning effect, and even more preferably 0.5 g / 10 min or more and 30 g / 10 min or less. The melt flow rate in this specification refers to a value measured in accordance with ASTM-D1238. Regarding the measurement conditions, when the thermoplastic resin (A) is an amorphous resin or a crystalline resin (e.g., AS resin) having a melting point of 220°C or less, the value is measured under the conditions of a measurement temperature of 220°C and a load of 10 kgf. When the melting point of the thermoplastic resin (A) exceeds 220°C, the value is measured under the standard measurement conditions for that resin. For example, polyamide 66 has a melting point of about 265°C, and is measured at a temperature of 275°C and a load of 5 kgf, while PET has a melting point of about 255°C, and is measured at a temperature of 285°C and a load of 2.16 kgf.

[0022] The content of the thermoplastic resin (A) is preferably in the range of 1 to 99% by mass, more preferably in the range of 5 to 98% by mass, and even more preferably in the range of 10 to 97% by mass, based on 100% by mass of the cleaning resin composition. The content of the thermoplastic resin (A) can be measured, for example, by GPC or other methods, specifically, by the qualitative and quantitative analysis methods described in the Examples below, or by other methods.

[0023] (Synthetic Wax (B)) Generally, wax is defined as a substance that is solid or semi-solid at room temperature, has a melting point of 40°C or higher, melts without decomposition when heated, and has low viscosity. Wax is also composed of various raw materials and is broadly classified into natural waxes, semi-synthetic waxes, and synthetic waxes. In this embodiment, synthetic wax is used from the viewpoint of cleaning workability, which can suppress the spraying and smoking of the cleaning resin composition from the molding machine. As the synthetic wax (B) in this embodiment, a wide variety of synthetic waxes used in general injection molding, extrusion molding, etc. can be used, and two or more synthetic waxes can also be used simultaneously.

[0024] Specific examples of the synthetic wax (B) include homopolymer polyethylene wax and polypropylene wax, copolymer ethylene vinyl acetate wax, ethylene acrylic acid wax, polar functional group-containing polyolefin wax, etc. From the viewpoint of suppressing the emission of smoke and spraying from the molding machine during cleaning work, homopolymer polyethylene wax or homopolymer polypropylene wax, which is non-hygroscopic and has good thermal stability, is preferred.

[0025] The molecular weight of the synthetic wax (B) is preferably 1,000 to 60,000 in weight average molecular weight, more preferably 3,000 to 55,000, and even more preferably 5,000 to 50,000. The melting point of the synthetic wax (B) is preferably 100 to 165°C, more preferably 102 to 163°C, and even more preferably 105 to 160°C. The type of synthetic wax (B) is not particularly limited, but a wax having a weight average molecular weight of 5,000 to 50,000 and a melting point of 105 to 160°C is most likely to provide a cleaning effect. The weight average molecular weight of the synthetic wax (B) can be measured, for example, by GPC or other methods. Specifically, it can be measured, for example, by the qualitative and quantitative analysis methods described in the Examples below, or by other methods.

[0026] The content of the synthetic wax (B) is 0.1% by mass or more and 20% by mass or less, preferably 0.3% by mass or more and 15% by mass or less, and more preferably 1.0% by mass or more and 10% by mass or less, based on 100% by mass of the cleaning resin composition. If the content of the synthetic wax (B) is less than 0.1% by mass, the synthetic wax (B) does not bleed out sufficiently, making it difficult to achieve cleaning effects. On the other hand, if the content of the synthetic wax (B) exceeds 20% by mass, excessive bleed-out occurs when the cleaning resin composition is introduced into the molding machine, causing poor screw engagement, which is unsuitable. The content of the synthetic wax (B) can be measured, for example, by GPC or other methods. Specifically, it can be measured, for example, by the qualitative and quantitative analysis methods described in the Examples below, or by other methods.

[0027] (Polyolefin Resin (C)) The polyolefin resin (C) used in this embodiment is preferably a polyethylene resin, a polypropylene resin, or a polybutene resin. Here, the polyethylene resin refers to a homopolymer of ethylene or a copolymer of ethylene and one or more other monomers, with an ethylene content of 50% by mass or more. The polypropylene resin refers to a homopolymer of propylene or a copolymer of propylene and one or more other monomers, with a propylene content of 50% by mass or more. The polybutene resin refers to a homopolymer of butene or a copolymer of butene and one or more other monomers, with a butene content of 50% by mass or more.

[0028] Examples of the polyethylene resin include polyethylene and ethylene-α-olefin copolymers, and specific examples thereof include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), linear very low-density polyethylene (VLDPE, ULDPE), and ultra-high molecular weight polyethylene (UHMWPE).

[0029] The ethylene-α-olefin copolymer is preferably a copolymer of ethylene and at least one selected from α-olefins having 3 to 20 carbon atoms, and more preferably a copolymer of ethylene and at least one selected from α-olefins having 3 to 12 carbon atoms. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosane, and these can be used alone or in combination of two or more.

[0030] Furthermore, as the ethylene-α-olefin copolymer, a copolymer of ethylene and at least one comonomer selected from a propylene comonomer, a butene comonomer, a hexene comonomer, and an octene comonomer is generally easily available and can be suitably used.

[0031] The polyethylene resin can be polymerized using a known catalyst such as a chromium catalyst, a Ziegler catalyst, or a metallocene catalyst, and from the viewpoint of cleaning performance, a chromium catalyst or a Ziegler catalyst having a wide molecular weight distribution is preferred, and a chromium catalyst or a metallocene catalyst having a long-chain branch of a molecular chain containing 6 or more carbon atoms is more preferred. Furthermore, from the viewpoint of cleaning performance, the polyethylene resin preferably has an MFR (measured in accordance with ASTM-D1238 under conditions of a measurement temperature of 190°C and a load of 2.16 kgf) of 0.01 to 30 g / 10 min, more preferably 0.05 to 25 g / 10 min, and even more preferably 0.1 to 20 g / 10 min.

[0032] The ultra-high molecular weight polyethylene may be an ethylene homopolymer or a copolymer of ethylene and one or more other monomers, each having a molecular weight of 1,000,000 or more. The copolymer refers to a copolymer containing 50% or more structural units derived from ethylene. The upper limit of the molecular weight is not particularly limited, but a molecular weight of 10,000,000 or less is practically preferred. Examples of the other monomer include, but are not limited to, α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosane; vinyl compounds such as vinyl acetate; aliphatic unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, and maleic acid; and aliphatic unsaturated carboxylic acid esters such as acrylic acid esters, methacrylic acid esters, fumaric acid esters, and maleic acid esters. Among the ultra-high molecular weight polyethylenes, ethylene homopolymers are preferred from the viewpoint of thermal stability.

[0033] The weight average molecular weight of the polyolefin resin (C) can be measured, for example, by GPC or other methods. Specifically, it can be measured, for example, by the qualitative and quantitative analysis methods described in the examples below or other methods.

[0034] The polyethylene resins may be used alone or in combination of two or more.

[0035] Examples of the polypropylene resin include polypropylene, propylene-α-olefin copolymer, and terpolymer of propylene, ethylene and α-olefin.

[0036] The propylene-α-olefin copolymer refers to a copolymer composed of propylene and at least one selected from α-olefins. The propylene-α-olefin copolymer is preferably a copolymer composed of propylene and at least one selected from ethylene and α-olefins having 4 to 20 carbon atoms, and more preferably a copolymer composed of propylene and at least one selected from ethylene and α-olefins having 4 to 8 carbon atoms. Examples of α-olefins having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosane, and these can be used alone or in combination of two or more. These copolymers may be in the form of block copolymers, random copolymers, or the like, and are preferably random copolymers of propylene and ethylene. As the propylene-α-olefin copolymer, a copolymer of propylene and at least one comonomer selected from ethylene comonomer, butene comonomer, hexene comonomer and octene comonomer is generally easily available and can be suitably used.

[0037] As the terpolymer of propylene, ethylene and an α-olefin, a terpolymer of propylene, ethylene and an α-olefin such as butene, hexene, octene, etc. can be suitably used. These terpolymers may be in the form of either a block copolymer or a random copolymer, and are preferably random copolymers of propylene, ethylene and butene.

[0038] The polypropylene resin may be not only a resin polymerized with a catalyst such as a Ziegler-Natta catalyst, but also a resin polymerized with a known catalyst such as a metallocene catalyst, and for example, syndiotactic polypropylene, isotactic polypropylene, etc. From the viewpoint of cleaning performance, the polypropylene resin preferably has an MFR (measured in accordance with ASTM-D1238 under conditions of a measurement temperature of 230°C and a load of 2.16 kgf) of 0.01 to 30.0 g / 10 min, more preferably 0.05 to 25 g / 10 min, and even more preferably 0.1 to 20 g / 10 min.

[0039] The polybutene resin has particularly excellent compatibility with polypropylene resins, and is therefore preferably used in combination with the polypropylene resins for the purpose of adjusting the melt viscosity.

[0040] As the polybutene-based resin, a crystalline copolymer of butene and at least one selected from ethylene, propylene and olefin-based compounds having 5 to 8 carbon atoms can be suitably used.

[0041] The glass transition temperature can be measured by DSC, specifically by the method described in the Examples below. The glass transition temperature is a value measured in accordance with ASTM-D-3418 and can be calculated by the midpoint method. When multiple glass transition temperatures exist in a copolymer or the like, the transition temperature with the largest baseline shift is taken as the glass transition temperature.

[0042] The content of the polyolefin resin (C) is preferably more than 0.1% by mass but less than 10% by mass, preferably 0.2% by mass or more but 9% by mass or less, and more preferably 0.3% by mass or more but 8% by mass or less, based on 100% by mass of the cleaning resin composition. A content of polyolefin resin (C) of less than 0.1% by mass is inappropriate because it is difficult to achieve the effect of improving raw material jamming. On the other hand, a content of polyolefin resin (C) of 10% by mass or more is inappropriate because, although the effect of improving raw material jamming is good, the polyolefin resin (C) itself tends to remain in the molding machine, which deteriorates its replaceability with the material to be molded after cleaning. The content of polyolefin resin (C) can be measured, for example, by GPC or other methods. Specifically, it can be measured, for example, by the qualitative and quantitative analysis methods described in the Examples below, or by other methods. From the viewpoint of workability and ease of raw material procurement, the polyolefin resin (C) preferably has a melting point of 80°C or higher and 260°C or lower, more preferably 90°C or higher and 250°C or lower, and even more preferably 100°C or higher and 240°C or lower. The reason for this effect is not entirely clear, but a melting point below 80°C results in increased stickiness and a tendency to adhere to metals such as cylinders and screws, making workability poor. A melting point above 260°C is unsuitable because it becomes difficult to obtain. The melting point can be measured by DSC, specifically by the method described in the Examples below. The melting point is the peak value measured in accordance with JIS-K-7210. When multiple melting points exist, such as in a copolymer, the highest peak value is taken as the melting point.

[0043] (Additives) Additives other than the synthetic wax (B), such as lubricants, surfactants, and antioxidants, may be added to the cleaning resin composition of this embodiment as long as they do not impair its inherent properties. The additives may be introduced into the resin by a known method so that the effects of each additive can be exerted. The additives may be used alone or in combination of two or more. From the viewpoint of production stability, the content of the additives is preferably 10% by mass or less relative to 100% by mass of the cleaning resin composition. The additives are described below.

[0044] (Lubricant) Examples of lubricants other than the synthetic wax (B) include, but are not limited to, organic acids, organic acid metal salts, organic acid amides, organic acid esters and other organic acid derivatives, various ester waxes, fluorine-based resins, mineral oils, etc. The lubricants may be used alone or in combination of two or more.

[0045] Examples of the organic acid include saturated fatty acids having 9 to 28 carbon atoms, unsaturated fatty acids having 9 to 28 carbon atoms, and benzoic acid.

[0046] The metal in the organic acid metal salt is not particularly limited, but examples thereof include sodium, potassium, lithium, cesium, magnesium, calcium, aluminum, zinc, iron, cobalt, barium, etc. As with the organic acids described above, examples of the hydrocarbon moiety in the organic acid metal salt include saturated fatty acids having 9 to 28 carbon atoms, unsaturated fatty acids having 9 to 28 carbon atoms, and benzoic acid.

[0047] Examples of the organic acid amide include saturated fatty acid amides, unsaturated fatty acid amides, saturated fatty acid bisamides, and unsaturated fatty acid bisamides having 9 to 28 carbon atoms.

[0048] Examples of the organic acid esters and ester waxes include saturated fatty acid esters having 9 to 28 carbon atoms, unsaturated fatty acid esters, medium-chain fatty acid triglycerides, polyol esters such as hardened oils, and the like.

[0049] Examples of the fluorine-based resin include PTFE, PFA, PVDF, PVDF-based copolymers, ETFE, and PFE.

[0050] The mineral oil is an oil obtained by refining petroleum, and examples thereof include saturated hydrocarbon oils including naphthene, also known as mineral oil, lubricating oil, and liquid paraffin, and isoparaffin.

[0051] (Surfactants) Examples of the surfactants include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. Specific examples of anionic surfactants include higher fatty acid alkali salts, alkyl sulfates, alkyl sulfonates, alkylaryl sulfonates, and sulfosuccinate salts. Specific examples of cationic surfactants include higher amine halogen acid salts, alkylpyridinium halides, and quaternary ammonium salts. Specific examples of nonionic surfactants include polyethylene glycol alkyl ethers, polyethylene glycol fatty acid esters, sorbitan fatty acid esters, and fatty acid monoglycerides. Specific examples of amphoteric surfactants include amino acids. The surfactants may be used alone or in combination of two or more.

[0052] (Antioxidant) Examples of the antioxidant include phenol-based, sulfur-based, phosphorus-based, amine-based, hindered phenol-based, hindered amine-based, hydrazine-based, etc. The above-mentioned antioxidants may be used alone or in combination of two or more.

[0053] The cleaning resin composition of this embodiment may contain inorganic fillers, inorganic foaming agents, etc. to exhibit high cleaning power for materials molded before cleaning. The effect of inorganic fillers, etc. on cleaning power is not necessarily clear, but it is thought that they improve cleaning power by scraping off dirt as a scrubbing agent. From the viewpoint of the balance between cleaning power for materials molded before cleaning and replacement ability for materials molded after cleaning, the total content of the inorganic fillers and inorganic foaming agents is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, relative to 100% by mass of the cleaning resin composition. The inorganic fillers, etc. will be described below.

[0054] (Inorganic Filler) In the present embodiment, the inorganic filler refers to an inorganic compound other than the inorganic foaming agent described below, and indicates both natural and synthetic compounds. Specific examples of such inorganic compounds include talc, mica, wollastonite, xonotlite, kaolin clay, montmorillonite, bentonite, sepiolite, imogolite, sericite, lawsonite, smectite, calcium sulfate fiber, calcium carbonate, magnesium carbonate, titanium oxide, aluminum hydroxide, magnesium hydroxide, zeolite, diatomaceous earth, glass powder, glass spheres, glass fiber, and shirasu balloons.

[0055] From the viewpoint of ease of substitution with the material to be molded after cleaning, the content of the inorganic filler is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, relative to 100% by mass of the cleaning resin composition. There is no particular lower limit for the content of the inorganic filler.

[0056] (Inorganic Foaming Agent) In this embodiment, the inorganic foaming agent refers to an inorganic compound that decomposes upon heating to foam, i.e., generate gas. Specific examples of the inorganic foaming agent include inorganic physical foaming agents such as water, hydrogen carbonates such as sodium bicarbonate (hereinafter also referred to as "baking soda"), potassium bicarbonate, and ammonium bicarbonate, carbonates such as sodium carbonate and ammonium carbonate, nitrites such as ammonium nitrite, hydrides such as sodium borohydride, azide compounds such as calcium azide, light metals such as magnesium and aluminum, a combination of sodium bicarbonate and acid, a combination of hydrogen peroxide and yeast, and a combination of aluminum powder and acid, among other known inorganic chemical foaming agents.

[0057] The content of the inorganic foaming agent is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, based on 100% by mass of the cleaning resin composition. There is no particular lower limit for the content of the inorganic foaming agent.

[0058] The high detergency of the present invention for materials molded before cleaning and the ease of substitution for materials to be molded after cleaning can be achieved by using a combination of thermoplastic resin (A) and synthetic wax (B). Although the reason for this is unclear, it is presumed that when the polarity difference between the thermoplastic resin (A) and the synthetic wax (B) is large, the synthetic wax (B) bleeds out onto the surface of the cleaning resin composition, promoting the flow of the cleaning resin composition near the wall surface inside the molding machine cylinder, thereby achieving the cleaning effect. From the viewpoint of the above-mentioned bleed-out, the solubility parameter δ of the thermoplastic resin (A) （Ａ） and the solubility parameter δ of the synthetic wax (B) （Ｂ） The absolute value of the difference between （Ａ） -δ （Ｂ） |) is 2.0 (cal / cm ３ ) １／２ It is preferable that the calorie content is 2.2 (cal / cm ３ ) １／２ More preferably, it is 2.4 (cal / cm ３ ) １／２ The greater the difference in solubility parameters (polarity difference) between the thermoplastic resin (A) and the synthetic wax (B), the better the cleaning power and ease of substitution. On the other hand, if the absolute value of the difference in solubility parameters is 7.0 (cal / cm ３ ) １／２ If it exceeds 7.0 (cal / cm), the compatibility will be significantly deteriorated, making it difficult to produce the cleaning resin composition. ３ ) １／２ It is preferably 6.5 (cal / cm ３ ) １／２ More preferably, 6.0 (cal / cm ３ ) １／２ The solubility parameter δ of the thermoplastic resin (A) is as follows: （Ａ） , the solubility parameter δ of the synthetic wax (B) （Ｂ） , and the solubility parameter δ of the polyolefin resin (C) （Ｃ）is calculated from the structural formulas of the thermoplastic resin (A), the synthetic wax (B), and the polyolefin resin (C) using the following formula based on the Fedors' estimation method (R.F. Fedors, Polym. Eng. Sci., 14(2), 147-154 (1974), hereinafter simply referred to as "Fedors' paper"). Fedors' formula: solubility parameter δ [(cal / cm ３ ) １／２ ]=(E ｖ / v) １／２ = (ΣΔe ｉ / ΣΔv ｉ ) １／２ E ｖ : Evaporation energy [cal / mol] v: Molar volume [cm ３ / mol] Δe ｉ : Vaporization energy of each component atom or atomic group [cal / mol] Δv ｉ : Molar volume of each component atom or atomic group [cm ３ / mol] Here, the evaporation energy and molar volume used for the solubility parameter δ (SP value) calculated by the above formula are values ​​at 25°C in the above Fedors paper. Solubility parameter δ of thermoplastic resin (A) （Ａ） , the solubility parameter δ of the synthetic wax (B) （Ｂ） , and the solubility parameter δ of the polyolefin resin (C) （Ｃ） is a value calculated at 25° C. The structural formulas of the thermoplastic resin (A), the synthetic wax (B), and the polyolefin resin (C) can be determined using ordinary structural analysis techniques such as IR, NMR, and mass spectrometry.

[0059] When two or more synthetic waxes are used as the synthetic wax (B), the solubility parameter δ （Ａ） , δ （Ｂ） , and δ （Ｃ） It is sufficient that the above relationship is satisfied for at least one component contained in the synthetic wax (B), and it is sufficient that the relationship is satisfied for any component that accounts for preferably 50 mass % or more, more preferably 60 mass % or more, of the total amount of the synthetic wax (B), and it is particularly preferable that the relationship is satisfied for all components in the synthetic wax (B).

[0060] As mentioned above, the synthetic wax (B) is preferably a homopolymer polyethylene wax or homopolymer polypropylene wax, which is non-hygroscopic and has good thermal stability, from the viewpoint of suppressing spraying and smoke generation from the molding machine during cleaning. On the other hand, polar functional group-containing polyolefin waxes, such as polyethylene waxes containing carboxylic anhydride groups or carbonyl groups and polypropylene waxes containing maleic anhydride groups, are hygroscopic and therefore prone to spraying and smoke generation from the molding machine during cleaning. Methods for promoting the flow of cleaning resin compositions include blending a lubricant or surfactant in addition to the synthetic wax (B). However, organic acid metal salts and organic acid amides have poor thermal stability, and many surfactants are hygroscopic. For example, the addition of saturated fatty acid bisamide ethylene bisstearic acid amide, anionic surfactant alkyl sulfonates, or sodium stearate can easily cause spraying and smoke generation from the molding machine during cleaning.

[0061] On the other hand, the flow promotion achieved by the lubrication provided by the synthetic wax (B) is likely to cause poor meshing of the cleaning resin composition. This has been particularly problematic during the cleaning process known as metering purge, where poor meshing of the cleaning resin composition prevents it from being fed from the raw material hopper of the molding machine into the cylinder, resulting in extended metering times or even failure to perform metering. This is thought to be due to reduced friction between the bleed-out synthetic wax (B) and the screw or the metal inner wall of the molding machine cylinder, causing poor meshing of the raw material. The present invention has found that blending a polyolefin resin (C) into the cleaning resin composition improves the meshing of the raw material. While the reason for this is unclear, it is believed that the ambient temperature below the molding machine hopper, typically in the molding conditions for engineering plastics, is often 10 to 40°C. Therefore, when the cleaning resin composition meshes with the polyolefin resin (C), which has a glass transition temperature of less than 40°C, softens, increasing friction with the screw or the metal inner wall of the cylinder, improving the meshing of the raw material. The glass transition point of the polyolefin resin (C) is preferably higher than −150° C. from the viewpoint of ease of raw material procurement, and is preferably lower than 40° C., more preferably lower than 30° C., and even more preferably lower than 20° C. so that the resin can be softened at the ambient temperature below the hopper.

[0062] In order to achieve both the flow promoting effect of the synthetic wax (B) by providing lubricity and the friction increasing effect of the polyolefin resin (C) by providing a softening component, the solubility parameter of the synthetic wax (B) must be equal to or greater than the solubility parameter δ of the thermoplastic resin (A). （Ａ） >δ of polyolefin resin (C) （Ｃ） ≥δ of thermoplastic resin (B) （Ｂ） Preferably, δ （Ａ） >δ （Ｃ） >δ （Ｂ） It is more preferable that the solubility parameter δ （Ａ） , δ （Ｂ） , and δ （Ｃ） The relationship is |δ （Ａ） -δ （Ｂ） |>|δ （Ｃ） -δ （Ｂ） |δ （Ａ） -δ（Ｂ） |>|δ （Ｃ） -δ （Ｂ） It is more preferable that |>0.

[0063] Furthermore, from the viewpoint of achieving both cleaning performance and suitability for metered purging, it is preferable that the polyolefin resin (C) and the synthetic wax (B) are incompatible with each other, and the solubility parameter δ of the polyolefin resin (C) is （Ｃ） and the solubility parameter δ of the synthetic wax (B) （Ｂ） The absolute value of the difference between （Ｃ） -δ （Ｂ） |) is 0.3 (cal / cm ３ ) １／２ It is preferable that the value is 0.4 (cal / cm ３ ) １／２ More preferably, it is 0.5 (cal / cm ３ ) １／２ More preferably, it is equal to or greater than this.

[0064] From the viewpoint of raw material biting property, it is preferable that the thermoplastic resin (A) and the polyolefin-based resin (C) are incompatible with each other, and the solubility parameter δ of the thermoplastic resin (A) is （Ａ） and the solubility parameter δ of the polyolefin resin (C) （Ｃ） The absolute value of the difference between （Ａ） -δ （Ｃ） |) is 2.0 (cal / cm ３ ) １／２ It is preferable that the calorie content is 2.2 (cal / cm ３ ) １／２ More preferably, it is 2.4 (cal / cm ３ ) １／２ When the difference in solubility parameters (polarity difference) between the thermoplastic resin (A) and the polyolefin resin (C) is within the above range, the effect of the raw material biting property tends to be excellent. On the other hand, when the absolute value of the difference in solubility parameters is 7.0 (cal / cm ３ ) １／２ If it exceeds 7.0 (cal / cm), the compatibility will be significantly deteriorated, making it difficult to produce the cleaning resin composition. ３ ) １／２ It is preferably 6.5 (cal / cm ３ )１／２ More preferably, 6.0 (cal / cm ３ ) １／２ The following is the result.

[0065] The cleaning resin composition of the present embodiment has a wall sliding velocity V ｓ (mm / s) on the X axis and true shear stress τ ｃｏｒｒｅｃｔ When the slope α obtained from the linear approximation line of the scatter diagram graph plotting the pressure (kPa) of the cleaning resin composition is controlled to 0.10 mm / (s·kPa) or more, it becomes easier to achieve both high detergency for materials molded before cleaning and easy replacement for materials to be molded after cleaning. It is more preferable to control the slope α to 0.13 mm / (s·kPa) or more, and even more preferable to control it to 0.16 mm / (s·kPa) or more. The reason for this is unclear, but it is known that, according to Newton's law of viscosity, Newtonian fluids have a slower flow rate near the wall than inside a circular pipe. It is presumed that the cleaning resin composition of this embodiment promotes flow near the wall, where the flow rate is slow and replacement is considered difficult, thereby facilitating high detergency for materials molded before cleaning and easy replacement for materials to be molded after cleaning. The upper limit of the slope α is not particularly limited, but is preferably 2.00 mm / (s·kPa) or less, more preferably 1.95 mm / (s·kPa) or less, and even more preferably 1.90 mm / (s·kPa) or less. ｓ The pressure (mm / s) and the slope α (mm / (s·kPa)) can be measured by the method described in the examples below.

[0066] From the viewpoint of cleaning effect, the melt flow rate of the cleaning resin composition of this embodiment is preferably 0.5 g / 10 min or more, more preferably 100 g / 10 min or less, and even more preferably 1 to 80 g / 10 min. The melt flow rate in this specification refers to a value measured in accordance with ASTM-D1238. When the thermoplastic resin (A) is an amorphous resin or a crystalline resin (e.g., AS resin) with a melting point of 220°C or less, the measurement was performed at a temperature of 220°C and a load of 10 kgf. When the thermoplastic resin (A) has a melting point exceeding 220°C, the measurement was performed under the standard measurement conditions for that resin. For example, polyamide 66 has a melting point of approximately 265°C, and the measurement was performed at a temperature of 275°C and a load of 5 kgf. PET has a melting point of approximately 255°C, and the measurement was performed at a temperature of 285°C and a load of 2.16 kgf.

[0067] The cleaning resin composition of this embodiment preferably has a thermal weight loss rate at 300°C, measured using a thermogravimetric analyzer when heated from 30°C to 400°C at a rate of 10°C / min, of 3% by mass or less, more preferably 2.8% by mass or less, and even more preferably 2.5% by mass or less. Setting the thermal weight loss rate within this range is preferable because additives and the like are not decomposed even when heated, ensuring sufficient workability. Furthermore, there is no particular restriction on the lower limit of the thermal weight loss rate. The thermal weight loss rate can be measured by the method described in the Examples below.

[0068] The cleaning resin composition of this embodiment preferably has a water content of 5,000 ppm or less, more preferably 4,800 ppm or less, and even more preferably 4,500 ppm or less, as measured by the Karl Fischer method. Setting the water content within this range can prevent the composition from spraying out of the molding machine during cleaning, ensuring sufficient workability. The lower limit of the water content is not particularly limited, but is preferably 50 ppm or more, more preferably 80 ppm or more, and even more preferably 100 ppm or more. The water content can be measured by the method described in the Examples below.

[0069] (Method for Producing Cleaning Resin Composition) The method for producing the cleaning resin composition of this embodiment is not particularly limited. For example, the cleaning resin composition can be produced by premixing the above components in a mixer, kneading and extruding the mixture in an extruder, and pelletizing the mixture.

[0070] (Shape of Cleaning Resin Composition) The shape of the cleaning resin composition of the present embodiment is not particularly limited as long as it does not impair the effects of the present invention, and examples thereof include cylindrical, spherical, flake, and powder shapes.

[0071] (Method for Cleaning a Molding Machine) The method for cleaning a molding machine (resin molding processing machine) according to this embodiment uses the above-described resin composition for cleaning a molding machine. The method for cleaning a resin molding processing machine according to this embodiment may also include a step of retaining the above-described resin composition for cleaning inside the resin molding processing machine. Specific examples of the above-described resin molding processing machine include an injection molding machine, an extrusion molding machine, and the like. The method for cleaning a resin molding processing machine according to this embodiment not only efficiently discharges the material molded before cleaning, but also easily replaces it with the material to be molded after cleaning. Furthermore, when the resin molding processing machine is shut down after cleaning, by retaining the resin composition in a state where it is filled inside the resin molding processing machine, there is an advantage that even if the material molded before cleaning remains inside the resin molding processing machine due to insufficient cleaning, thermal degradation of the remaining material can be prevented.

[0072] When a cleaning agent with weak cleaning power is used, not only do materials molded before cleaning remain in the resin molding machine and become contaminated as foreign matter with the materials to be molded after cleaning, but the remaining molding material deteriorates when the molding machine is shut down and becomes contaminated as degraded material when the molding machine is started up again. Therefore, to avoid this problem, inorganic fillers or inorganic foaming agents are often blended into the thermoplastic resin base material to increase the cleaning power of the cleaning agent. However, these cleaning ingredients are not easily replaced by the materials to be molded after cleaning, so when they are used to clean the inside of a resin molding machine, it takes a long time for them to be replaced by the next molding material, and there is a problem that the loss of molding material is large and production efficiency is likely to decrease.

[0073] The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0074] The measuring and evaluation methods for the cleaning resin compositions of the Examples and Comparative Examples are as follows.

[0075] <Measurement of solubility parameter δ> In the structural formulas of the thermoplastic resin (A), the synthetic wax (B), and the polyolefin resin (C), the solubility parameter δ of each was calculated from the following formula using the Fedors estimation method. （Ａ） , δ （Ｂ） , and δ （Ｃ） (value calculated at 25°C) was calculated. Fedors' formula: solubility parameter δ [(cal / cm ３ ) １／２ ]=(E ｖ / v) １／２ = (ΣΔe ｉ / ΣΔv ｉ ) １／２ E ｖ : Evaporation energy [cal / mol] v: Molar volume [cm ３ / mol] Δe ｉ : Vaporization energy of each component atom or atomic group [cal / mol] Δv ｉ : Molar volume of each component atom or atomic group [cm ３ The structural formulas of the thermoplastic resin (A) and the synthetic wax (B) were determined using conventional structural analysis techniques such as IR, NMR, and mass spectrometry. [Solubility parameter δ （Ａ） and δ （Ｂ） Absolute value evaluation standard of the difference between （Ａ） and δ （Ｂ） The absolute value of the difference is 2.4 (cal / cm ３ ) １／２ or more, and cleaning property is particularly good B: δ （Ａ） and δ （Ｂ） The absolute value of the difference is 2.2 (cal / cm ３ ) １／２ More than 2.4 (cal / cm ３ ) １／２ C: δ is less than 50% and has better cleaning properties （Ａ） and δ （Ｂ）The absolute value of the difference is 2.0 (cal / cm ３ ) １／２ More than 2.2 (cal / cm ３ ) １／２ Less than δ, and cleaning property is good （Ａ） and δ （Ｂ） The absolute value of the difference is 2.0 (cal / cm ３ ) １／２ The solubility parameter δ （Ｃ） and δ （Ｂ） Absolute value evaluation standard of the difference between （Ｃ） and δ （Ｂ） The absolute value of the difference is 0.5 (cal / cm ３ ) １／２ or more, and the biting property of the raw material is particularly good. A': δ （Ｃ） and δ （Ｂ） The absolute value of the difference is 0.4 (cal / cm ３ ) １／２ 0.5 (cal / cm) or more ３ ) １／２ B: δ is less than 100% and the raw material biting property is even better. （Ｃ） and δ （Ｂ） The absolute value of the difference is 0.3 (cal / cm ３ ) １／２ More than 0.4 (cal / cm ３ ) １／２ C: δ is less than 100% and the raw material biting property is better. （Ｃ） and δ （Ｂ） The absolute value of the difference is 0 (cal / cm ３ ) １／２ 0.3 (cal / cm) or more ３ ) １／２ less than 100%, which allows for good biting of raw materials.

[0076] <Glass transition point measurement> Measurements were performed in accordance with ASTM-D-3418 using a thermal analyzer (Diamond DSC, manufactured by Perkin Elmer) and calculated by the midpoint method. In addition, when multiple glass transition points exist in a copolymer or the like, the transition point with the largest baseline shift was taken as the glass transition point. <Melting point measurement> Measurements were performed in accordance with JIS-K-7210 using a thermal analyzer (Diamond DSC, manufactured by Perkin Elmer), and the melting point was calculated. In order to cancel the thermal history of the resin, the temperature was increased from 0°C to 300°C at a heating rate of 10°C / min, and then decreased from 300°C to 0°C at a heating rate of 10°C / min. The melting point was then measured and evaluated when the temperature was increased again from 0°C to 300°C at a heating rate of 10°C / min.

[0077] <Wall sliding velocity V ｓ and the true shear stress τ ｃｏｒｒｅｃｔ Measurement of the slope α of the shear stress vs. the shear stress using a twin capillary rheometer (RH10 manufactured by Malvern) at a temperature of 220°C, using three combinations of long dies (capillary dies) and short dies (orifice dies) shown in (i) to (iii) below, and using Burgley correction to measure the true shear stress τ ｃｏｒｒｅｃｔwas calculated. Note that Rabinowitsch correction was not used. Orifice die combinations and piston extrusion speed conditions (i) Long die (L / d = 20, diameter 0.5 mm, inlet angle 90°), and Short die (L / d = 0.5, diameter 0.5 mm, inlet angle 90°) Piston speeds (mm / min) were 0.05, 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 5, 7.5, 10, 15, 20, and 30. (ii) Long die (L / d = 16, diameter 1 mm, inlet angle 90°), and Short die (L / d = 0.25, diameter 1 mm, inlet angle 90°) Piston speeds (mm / min) were 0.5, 1, 2, 3, 5, 7.5, 10, 15, 20, 30, 50, 75, and 100. (iii) Long die (L / d = 16, diameter 2 mm, inlet angle 90°), and Short die (L / d = 0.125, diameter 2 mm, inlet angle 90°) Piston speed (mm / min) is 1, 3, 5, 7.5, 10, 15, 20, 30, 50, 75, 100, 150, 300. Inlet pressure loss P is calculated using the following formula (1). ０ Calculate the inflow pressure loss P ０ and the corrected true shear stress τ from equation (2) ｃｏｒｒｅｃｔ was sought. ０ = (P ｓ ・L Ｌ -P Ｌ ・L Ｓ ) / (L Ｌ -L Ｓ )...Formula (1) τ ｃｏｒｒｅｃｔ [kPa] = (P Ｌ -P ０ ) d / 4L Ｌ ...Formula (2) (wherein, P ０ : Inlet pressure loss of short die, or P Ｌ -P ｓ The pressure at L / D = 0 obtained by extrapolating from the value of (the calculated pressure value of the long die P Ｌ to the pressure measurement value P of the short die ｓ The line connecting these points is extended to the point of length 0, and the pressure at the point where it intersects with the pressure Y axis), P ｓ : Pressure loss occurring on the short die side, P Ｌ : Pressure loss occurring on the long die side, L Ｓ : Length of short die (mm), LＬ : length of long die (mm), d: diameter of die capillary (mm)) Sliding velocity V ｓ The analysis was performed using equation (3) based on the Moony method, assuming that y = ax + b. The analyzed shear stress τ ｃｏｒｒｅｃｔ Here, using Microsoft Excel, the X axis is 1 / R and the Y axis is γ ａ Create a scatter plot graph of the above, and multiply the slope obtained from the linear approximation by 1 / 4 to get V. ｓ , intercept is γ Ｔ γ ａ = γ Ｔ +4V ｓ / R...Formula (3) (where γ ａ : apparent shear rate (1 / s), γ Ｔ : true shear rate (1 / s), V ｓ : sliding speed (mm / s), R: die radius (mm)) Furthermore, using Microsoft Excel, the true shear stress τ corrected on the X axis was calculated. ｃｏｒｒｅｃｔ , the wall slip velocity V on the Y axis ｓ A scatter plot graph was created, and the slope α (mm / (s·kPa)) of the straight line obtained by linear approximation was calculated. ｃｏｒｒｅｃｔ The slope α was set to 3 levels or more, and the R-squared value of the approximation curve was set to 0.8 or more. [Slope α evaluation criteria] A: The slope α was 0.16 mm / (s·kPa) or more, the sliding speed effect was realized, and cleaning performance was particularly good B: The slope α was 0.13 mm / (s·kPa) or more and less than 0.16 mm / (s·kPa), the sliding speed effect was realized, and cleaning performance was even better C: The slope α was 0.10 mm / (s·kPa) or more and less than 0.13 mm / (s·kPa), the sliding speed effect was realized, and cleaning performance was good D: The slope α was less than 0.10 mm / (s·kPa), the sliding speed effect was insufficient, and cleaning was difficult

[0078] <Measurement of Heat Weight Loss Rate> Using a simultaneous thermogravimetry and differential thermal analyzer (TGA-DTA2000SR manufactured by Bruker), measurements were carried out under air from 30°C to 400°C at a temperature increase rate of 10°C / min, and the weight loss rate (mass%) at 300°C was measured. [Evaluation criteria for heat weight loss] A: The heat weight loss rate was 3% by mass or less, no smoke was emitted from the molding machine during cleaning, and workability was good. D: The heat weight loss rate was more than 3% by mass, and smoke was emitted from the molding machine during cleaning, and workability was poor.

[0079] <Moisture content measurement> Using a Karl Fischer moisture meter (MKC-510N manufactured by Kyoto Electronics Manufacturing Co., Ltd.), measurements were taken in accordance with JIS K7251-B method (moisture vaporization method) at a vaporization temperature of 185°C for 20 minutes, with nitrogen gas (200 mL / min±10 mL / min) as the carrier gas, and n=2 measurements, to obtain an average moisture content (ppm). [Moisture content evaluation criteria] A: Moisture content is 5000 ppm or less, no spraying from the molding machine during cleaning, and workability is good. D: Moisture content is more than 5000 ppm, there is a risk of spraying from the molding machine during cleaning, and workability is poor.

[0080] <Qualitative and quantitative analysis of thermoplastic resin (A), synthetic wax (B), and polyolefin resin (C)> Qualitative and quantitative analysis of the thermoplastic resin (A), synthetic wax (B), and polyolefin resin (C) contained in the resin composition (qualitative analysis of resin type and molecular weight and quantitative analysis of component content ratio) was performed using a combination of solvent fractionation, FT-IR, high-temperature GPC-IR, Thermal Gradient Interaction Chromatography (hereinafter referred to as TGIC), Crystallization Elution Fractionation (hereinafter referred to as CEF), and cross-fractionation chromatography (hereinafter referred to as CFC). When the thermoplastic resin (A) was a styrene-acrylonitrile copolymer, qualitative and quantitative analysis was performed by solvent fractionation according to the following flow scheme. (1) The resin composition was separated into an acetone-insoluble fraction and a soluble fraction using acetone, and (2) the acetone-insoluble fraction was separated into a chloroform-insoluble fraction and a soluble fraction using chloroform. The resin composition, acetone-soluble fraction, acetone-insoluble fraction, chloroform-soluble fraction, and chloroform-insoluble fraction were analyzed using an FT / IR-4100 (manufactured by JASCO Corporation) with FR-IT / transmission method / resolution of 4 cm. －1 The pressed film was measured 16 times and qualitative analysis was performed. The pressed film was produced at a heat press temperature of 180°C for a press time of 180 seconds, or at a press temperature and press time at which the resin composition, each soluble component, and each insoluble component melted. Qualitative and quantitative analysis of the synthetic wax (B) and polyolefin resin (C) was performed using the chloroform-insoluble component and / or the acetone-insoluble component according to the following procedure. (3)-1: When the synthetic wax (B) and the polyolefin resin (C) are the same resin type, a GPC-IR type gel permeation chromatograph (manufactured by Polymer Char) equipped with a built-in IR6 MCT infrared detector (manufactured by Polymer Char) was used as the GPC-IR, and the mobile solvent was o-dichlorobenzene ODCB (with antioxidant BHT added). The columns were 2x TSKgel GMH6-HT + 2x TSKgel GMH6-HTL (manufactured by Tosoh Corporation, length 7.5 ID x 30 cm, detection wavelength 140°C). ２ 3.42μm (2920cm －１ ), Methyl Sensor CH ３3.38μm (2960cm －１ ), carbonyl sensor C═O 5.75 μm (1740 cm －１ The sample concentration was 8 mg / 8 mL, and the dissolution conditions were 150°C, 60 min, and N ２ The sample was filtered using a 10 μm inline filter. The injection volume was 0.4 mL, the column was calibrated using monodisperse polystyrene (TSKgel standard polystyrene, manufactured by Tosoh Corporation), and the molecular weight was converted using a standard conversion method (polystyrene conversion). However, the high-temperature GPC method is a relative method based on a structural curve and does not take into account the influence of molecular weight reduction due to decomposition of the standard substance. In addition, if the molecular weight falls outside the range of the monodisperse polystyrene standard data for the calibration curve (molecular weight 5.9 million to 20.6 million), the calibration curve was extrapolated to calculate the molecular weight. Quantitative analysis was performed using the obtained differential molecular weight distribution curve (Derivative) and the integrated intensity (% Cumulative). When the peaks of the synthetic wax (B) and the polyolefin resin (C) overlap, the position corresponding to the valley of the peak in the differential molecular weight distribution curve was calculated, or when no valley was observed, quantitative analysis was performed by vertical division at the point where the slope changed and became nearly flat, and the content ratio of each component in the resin composition was determined from the component content ratios calculated by the above solvent fractionation and FT-IR and GPC-IR. (3)-2: In the case of synthetic wax (B) and polyolefin resin (C), which are different resin types, a high-throughput composition distribution analyzer (manufactured by Polymer Char) equipped with a built-in IR5 MCT infrared detector (manufactured by Polymer Char) was used as the TGIC. The mobile solvent was o-dichlorobenzene ODCB (with antioxidant BHT added). The column was a porous graphite carbon column, Hypercarb high-temperature compatible type (manufactured by THERMO, inner diameter 4.6 mm, length 100 mm, particle size 5 μm). The detection wavelength was methylene sensor CH ２ 3.42μm (2920cm －１ ), Methyl Sensor CH ３ 3.38μm (2960cm －１ The sample concentration was 8 mg / 8 mL, and the dissolution conditions were 150°C, 60 min, and N ２The sample was filtered using a 10 μm inline filter under atmospheric pressure. The injection volume was 0.2 mL, the temperature was lowered from 140°C to -20°C at a rate of 2°C / min with a flow rate of 0.0 mL / min, and the temperature was raised from -20°C to 165°C at a rate of 2°C / min with a flow rate of 0.5 mL / min. The component content ratios in the resin composition were determined from the component content ratios calculated from the solvent fractionation, FT-IR, and TGIC.

[0081] <Measurement of Raw Material Biting Property> A black colored PPE resin molding material was used in an injection molding machine with the cylinder and nozzle temperatures raised to 280°C. 1 kg of the resin composition for molding machine cleaning shown in Tables 1 and 2 was added to the injection molding machine, and a metering purge operation (metering injection operation) was carried out under conditions of a metering stroke of 50 mm and a back pressure of 2 MPa. The average time required for metering one shot and the number of shots until cleaning was complete were measured. The results are shown in Tables 1 and 2. The shorter the metering time, the more stable the raw material biting property was, and the results were evaluated according to the following evaluation criteria. [Evaluation criteria for raw material biting property] A: The time required for metering one shot was 10 seconds or less, and the raw material biting property was particularly good. B: The time required for metering one shot was more than 10 seconds and not more than 20 seconds, and the raw material biting property was better. C: The time required for metering one shot was more than 20 seconds and not more than 30 seconds, and the raw material biting property was good. D: The time required for metering one shot was longer than 30 seconds, and the metering was poor, making cleaning difficult. [Evaluation criteria for metering purge suitability] A: The time required for cleaning completion (product of the average time required for one shot and the total number of shots) was less than 150 seconds, and the metering purge suitability was particularly good. B: The time required for cleaning completion (product of the average time required for one shot and the total number of shots) was less than 200 seconds, and the metering purge suitability was better. C: The time required for cleaning completion (product of the average time required for one shot and the total number of shots) was less than 250 seconds, and the metering purge suitability was better. D: The time required to complete cleaning (the product of the average time required for one shot and the total number of shots) was 250 seconds or more, and the suitability for metering purge was poor, making cleaning difficult.

[0082] <Evaluation of Detergency and Replacement> 1 kg of a black-colored ABS resin molding material was charged into an injection molding machine with the cylinder and nozzle heated to 220°C. After filling, the molding machine was emptied by ejection using an injection operation. Next, 1 kg of the molding machine cleaning resin composition shown in Tables 1 and 2 was charged into the injection molding machine, and an injection operation (cleaning injection operation) was performed. The amount of purged debris of the molding machine cleaning resin composition (required mass for cleaning in Tables 1 and 2) required until the effects of the black-colored ABS resin were eliminated was measured. Finally, to replace the molding machine cleaning resin composition, 2 kg of a GPPS transparent molding material was charged and an injection operation (replacement injection operation) was performed. The amount of purged debris of the GPPS transparent molding material used until the effects of residue (such as foreign matter or coloration that impairs transparency) were confirmed (required mass for replacement in Tables 1 and 2) was measured. The results are shown in Tables 1 and 2. The smaller the amount of purged debris of the resin composition for cleaning molding machines from the black-colored ABS product, the better the cleaning power, and the evaluation was based on the following criteria. [Cleaning Power Evaluation Criteria] A: The amount of purged debris was 0.3 kg or less, and cleaning properties were particularly good. B: The amount of purged debris was more than 0.3 kg and 0.4 kg or less, and cleaning properties were even better. C: The amount of purged debris was more than 0.4 kg and 0.5 kg or less, and cleaning properties were good. D: The amount of purged debris was more than 0.5 kg, and cleaning was difficult. Furthermore, the smaller the amount of purged debris of the GPPS transparent molding material from the resin composition for cleaning molding machines, the better the replacement ability, and the evaluation was based on the following criteria. [Replacement Evaluation Criteria] A: The amount of purged debris was 1.0 kg or less, and cleaning properties were particularly good. B: The amount of purged debris was more than 1.0 kg and 1.5 kg or less, and cleaning properties were good. D: The amount of purged debris was more than 1.5 kg, and replacement from the cleaning resin composition was difficult.

[0083] When the melting point of the thermoplastic resin (A) was 200°C or higher or the glass transition temperature was 130°C or higher, 1 kg of black-colored PPS raw material was charged into an injection molding machine with the cylinder and nozzle temperatures raised to 330°C for cleaning evaluation. After filling, the molding machine was emptied by ejecting the raw material through an injection operation. Next, 1 kg of the molding machine cleaning resin composition shown in Tables 1 and 2 was charged into the injection molding machine and an injection operation (cleaning injection operation) was performed. The amount of purged debris of the molding machine cleaning resin composition (required mass for cleaning in Tables 1 and 2) required until the effects of the black-colored PPS product disappeared was measured. Finally, to replace the molding machine cleaning resin composition, 2 kg of PC transparent molding material was charged and an injection operation (replacement injection operation) was performed. The amount of purged debris of the PC transparent molding material used until the effects of residues (such as foreign matter or coloration that impairs transparency) were confirmed (required mass for replacement in Tables 1 and 2) was measured. The results are shown in Tables 1 and 2. The smaller the amount of purged debris of the resin composition for cleaning a molding machine from the black-colored PPS product, the better the cleaning power, and the evaluation was based on the following criteria. [Cleaning Power Evaluation Criteria] A: The amount of purged debris was 0.5 kg or less, and cleaning properties were particularly good. B: The amount of purged debris was more than 0.5 kg and 0.6 kg or less, and cleaning properties were even better. C: The amount of purged debris was more than 0.6 kg and 0.7 kg or less, and cleaning properties were good. D: The amount of purged debris was more than 0.7 kg, and cleaning was difficult. Furthermore, the smaller the amount of purged debris of the PC transparent molding material from the resin composition for cleaning a molding machine, the better the replacement ability, and the evaluation was based on the following criteria. [Replacement Evaluation Criteria] A: The amount of purged debris was 1.5 kg or less, and cleaning properties were particularly good. B: The amount of purged debris was more than 1.5 kg and 2.0 kg or less, and cleaning properties were good. D: The amount of purged debris was more than 2.0 kg, and replacement from the cleaning resin composition was difficult.

[0084] The raw materials used in the examples and comparative examples are as follows.

[0085] [Thermoplastic resin (A)] AS1: styrene-acrylonitrile resin (Stylac manufactured by Asahi Kasei, weight average molecular weight: 130,000, MFR = 13 g / 10 min; 220 ° C, 10 kgf) AS2: styrene-acrylonitrile resin (LURAN manufactured by INEOS, weight average molecular weight: 180,000, MFR = 12 g / 10 min; 220 ° C, 10 kgf) PA: nylon 66 resin (Leona manufactured by Asahi Kasei, MFR = 7 g / 10 min; 275 ° C, 5 kgf) PC: polycarbonate resin (Wonderlite manufactured by Asahi Kasei Taiwan Co., Ltd., 10 g / 10 min; 220 ° C, 10 kgf) PET: polyester resin (Remapet manufactured by Mitsubishi Engineering Plastics, 30 g / 10 min; 285 ° C, 2.16 kgf) HD: High-density polyethylene resin (Suntec manufactured by Asahi Kasei, 4g / 10min; 220°C, 10kgf) PP: Polypropylene resin (Homo PP manufactured by Sunallomer, 6g / 10min; 220°C, 10kgf) PS: Polystyrene resin (GPPS manufactured by PS Japan, 16g / 10min; 220°C, 10kgf) EEA: Ethylene ethyl acrylate resin (Elbaloy AC manufactured by Mitsui DuPont Polychemicals, 20g / 10min; 220°C, 10kgf) EMMA: Ethylene methyl methacrylate resin (Acryft 1 manufactured by Mitsui DuPont Polychemicals, 18g / 10min; 220°C, 10kgf) Acid-modified polyethylene (Nucrel manufactured by Mitsui DuPont Polychemicals, 14g / 10min; 220°C, 10kgf) Acid-modified polypropylene (Modic manufactured by Mitsubishi Chemical Corporation, 16 g / 10 min; 220°C, 10 kgf)

[0086] [Synthetic Waxes (B)] PP wax: homopolymer polypropylene wax (weight average molecular weight: 40,000, melting point: 145°C) PE wax 1: homopolymer polyethylene wax (weight average molecular weight: 13,000, melting point: 127°C) PE wax 2: homopolymer polyethylene wax (weight average molecular weight: 4,300, melting point: 122°C) PE wax 3: homopolymer polyethylene wax (weight average molecular weight: 1,100, melting point: 116°C) MAH-PE wax: maleic anhydride modified PE wax (Hiwax manufactured by Mitsui Chemicals, weight average molecular weight: 24,000, melting point: 142°C) MAH-PP wax: maleic anhydride modified PP wax (UMEX manufactured by Sanyo Chemical Industries, weight average molecular weight: 30,000, melting point: 135°C) The weight average molecular weight of the synthetic wax (B) was measured using an ultra-high temperature GPC (manufactured by Senshu Scientific Co., Ltd.) with 1-chloronaphthalene as an eluent and polystyrene as a standard substance at a column temperature of 210° C. A differential refractive index (RI) detector was used as the detector.

[0087] [Polyolefin resin (C)] PE1: Ultra-high molecular weight polyethylene resin (Sunfine UH950 manufactured by Asahi Kasei), glass transition point -120°C PE2: Low-density polyethylene resin (Suntec M2102 manufactured by Asahi Kasei), glass transition point -120°C PE3: High-density polyethylene resin (Suntec B770 manufactured by Asahi Kasei), glass transition point -119°C PP1: Polypropylene resin (PB170A manufactured by Sunallomer), glass transition point 0°C PP2: Polypropylene resin (PL500A manufactured by Sunallomer), glass transition point 2°C ABS: Acrylonitrile-butadiene-styrene copolymer resin (Toyolac manufactured by Toray), glass transition point 104°C

[0088] [Inorganic filler] Glass fiber (chopped strand manufactured by Nippon Electric Glass Co., Ltd.) Wollastonite (NYGLOS manufactured by NYCO Minerals Inc.) Talc (MICRO ACE manufactured by Nippon Talc Co., Ltd.) [Other additives] PEO: polyethylene oxide (ALKOX manufactured by Meisei Chemical Industry Co., Ltd.) Liquid paraffin (Moresco White manufactured by MORESCO Corporation) Non-ionic surfactant: polyoxyethylene and diisodecyl adipate Anionic surfactant: sodium dodecylbenzenesulfonate, zinc stearate EBS: ethylene bisstearamide

[0089] [Example 1] The components shown in Table 1 were mixed and melt-kneaded using an extruder. The melt-kneaded mixture was extruded into strands, cooled with water, and then cut with a strand cutter to obtain pellets of a resin composition for cleaning molding machines. The kneading conditions were a cylinder temperature of 270°C and an extrusion rate of 200 kg / hour. The evaluation results of the obtained resin composition for cleaning molding machines are shown in Table 1.

[0090] [Examples 2 to 28] Pellet-shaped resin compositions for cleaning molding machines were obtained in the same manner as in Example 1, except that the compositions were changed as shown in Table 1. Table 1 shows the evaluation results of the obtained resin compositions for cleaning molding machines.

[0091] [Examples 29 to 31] When the melting point of the thermoplastic resin (A) was 200°C or higher or the glass transition temperature was 130°C or higher, the kneading conditions were a cylinder temperature of 330°C and an extrusion rate of 200 kg / hour. The evaluation results of the obtained resin compositions for cleaning molding machines are shown in Table 1.

[0092] Comparative Examples 1 to 21 Pellet-shaped resin compositions for cleaning molding machines were obtained in the same manner as in Example 1, except that the compositions were changed as shown in Table 2. Table 2 shows the evaluation results of the obtained resin compositions for cleaning molding machines.

[0093]

[0094]

[0095] The above results show that the resin compositions for cleaning molding machines obtained in Examples 1 to 31 have good cleaning properties and easy replacement, and are also excellent in metered purging suitability and workability. On the other hand, the above results show that the resin compositions for cleaning molding machines obtained in Comparative Examples 1 to 21 have insufficient cleaning power and / or replacement ability, or are inadequate in raw material biting ability and / or metered purging suitability and workability.

[0096] The resin composition for cleaning molding machines of the present invention not only exhibits excellent cleaning performance and displacement ability, but also has excellent suitability for metered purging and workability, and is useful for cleaning thermoplastic resins, particularly as a cleaning agent composition for injection molding machines and extrusion molding machines.

Claims

DEPCT681. Resin composition for cleaning casting machines which consists of at least thermoplastic resin (A), synthetic wax (B) and a polyolefin-based resin (C) where the absolute value of the difference between the melting condition parameter delta (A) of thermoplastic resin (A) and the melting condition parameter delta (B) of synthetic wax (B) is 2.0 (kcal / cm³) 1 / 2 or more and 7.0 (kcal / cm³) 1 / 2 or less, the mixing volume of the polyolefin-based resin component is 1. Main component (C) greater than 0.1% by mass and less than 10% by mass and glass transition temperature of polyolefin-based resins (C) above -150°C and below 40°C.

2. Resin composition for cleaning casting machines according to claim 1, where thermoplastic resin (A) is a polycarbonate-based resin.

3. Resin composition for cleaning casting machines according to claim 1 or 2, where synthetic wax (B) is a polyethylene wax homopolymer or polypropylene wax homopolymer. 4.Resin composition for cleaning casting machines according to claim 1 or 2 where the average molecular weight by weight of synthetic wax (B) is 1000 to 50,000.

5. Resin composition for cleaning casting machines according to claim 1 or 2 where the amount of synthetic wax (B) is 0.1 to 20% by mass.

6. Resin composition for cleaning casting machines according to claim 1 or 2 where the relationship among the delta solubility parameters (A) of the first thermoplastic resin (A), delta solubility parameters (B), of the synthetic wax (B) is 0.1 to 20% by mass.

7. Resin composition for cleaning the casting machine according to claim 1 or 2 where the absolute value of the difference between the melting parameter delta (A) of thermoplastic resin (A) and the melting parameter delta (C) of the polyolefin-based resin (C) is 2.0 (cal / cm³) 1 / 2 or more and 7.0 (cal / cm³) 1 / 2 or less. 8.Resin composition for cleaning casting machines according to claim 1 or 2, where the slope determined from the linear approximation line in the scatter plot graph plotting the fading velocity Vs (mm / s) and the actual shear stress / correct torque (kPa) is 0.10 mm / (s•kPa) or more; 9. Resin composition for cleaning casting machines according to claim 1 or 2, where the water content measured by the Karl Fischer method is 5000 parts per million or less; 10. Resin composition for cleaning casting machines according to claim 1 or 2, where the weight loss rate upon heating at 300°C is 3% by mass or less.