Molding machine cleaner

Abstract

To provide a molding machine detergent that can achieve both of high detergency and easy replacement.SOLUTION: A molding machine detergent in the present invention contains polyethylene (A), an inorganic filler (B), a modified polyethylene (C), a surfactant (D) and a metallic soap (E). The polyethylene (A) is an ethylene polymer composition that contains 5-75 mass% of a component (a-1) comprising an ultra-high-molecular-weight ethylenic polymer with an intrinsic viscosity [η] of 10-40 dl / g, and 95-25 mass% of a component (a-2) comprising a low-molecular-weight or high-molecular-weight ethylenic polymer with an intrinsic viscosity [η] of 0.1-5 dl / g (where the total amount of the component (a-1) and the component (a-2) is 100 mass%). The polyethylene (A) has a density of 930-980 kg / m3 and an intrinsic viscosity [η] of 1-35 dl / g.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a molding machine cleaner used to remove molding materials such as resin remaining inside a molding machine. [Background technology]

[0002] Generally, various molding machines such as extrusion molding machines and injection molding machines are used to mold resin products. In resin molding using such molding machines, molding materials such as resin and additives remain inside the molding machine after the molding operation is completed, so the inside of the molding machine may need to be cleaned.

[0003] Conventionally, cleaning of the inside of such a molding machine has been carried out by disassembling the molding machine, but disassembling the molding machine requires a great deal of time and effort and significantly reduces productivity. Therefore, in recent years, development has been underway of cleaning agents that can be introduced into the molding machine and used to clean the inside of the molding machine without disassembling the molding machine, simply by carrying out normal molding operations (see, for example, Patent Documents 1 to 3).

[0004] When cleaning the inside of a molding machine with a cleaner, typically, molding operations (cleaning work) using the cleaner are performed multiple times to remove residues from inside the molding machine, and then molding operations (replacement work) using the molding material, such as resin, to be used in the next molding are performed multiple times to remove the remaining cleaner. Therefore, the cleaner must have high cleanability to remove residues from inside the molding machine, and be easily replaceable so that it is removed by the next molding material and does not remain inside the molding machine. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2000 / 056514 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-348600 [Patent Document 3] International Publication No. 2019 / 039542 Summary of the Invention [Problem to be solved by the invention]

[0006] From the viewpoint of work efficiency and cost, there is a demand for cleaning agents that can further reduce the number of cleaning and replacement operations compared to conventional cleaning agents.

[0007] An object of the present invention is to provide a molding machine cleaner that can achieve both high cleaning properties and ease of replacement (low residue). [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by a molding machine cleaner containing a specific polyethylene, an inorganic filler, a modified polyethylene, a surfactant, and a metal soap, and have thus completed the present invention.

[0009] The molding machine cleaner of the present invention contains polyethylene (A), inorganic filler (B), modified polyethylene (C), surfactant (D), and metal soap (E), the polyethylene (A) is an ethylene polymer composition comprising 5 to 75% by mass of a component (a-1) consisting of an ultra-high molecular weight ethylene polymer having an intrinsic viscosity [η] measured in decalin solvent at 135°C in the range of 10 to 40 dL / g, and 95 to 25% by mass of a component (a-2) consisting of a low- to high-molecular weight ethylene polymer having an intrinsic viscosity [η] measured in decalin solvent at 135°C in the range of 0.1 to 5 dL / g (wherein the total amount of component (a-1) and component (a-2) is taken as 100% by mass); The density of the polyethylene (A) (in accordance with ASTM D1505) is 930 to 980 kg / m 3 and the intrinsic viscosity [η] measured in decalin solvent at 135° C. is 1 to 35 dl / g. [Effects of the Invention]

[0010] According to the molding machine cleaning agent of the present invention, both high detergency and easy replaceability (low residue) can be achieved.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described in detail. In this specification, the notation "X to Y" in the description of the numerical range represents X or more and Y or less when X < Y, and Y or more and X or less when X > Y, unless otherwise specified. For example, "0.1 to 5 dl / g" means "0.1 dl / g or more and 5 dl / g or less".

[0012] The molding machine cleaning agent according to the present invention contains polyethylene (A), an inorganic filler (B), modified polyethylene (C), a surfactant (D), and a metal soap (E). Hereinafter, each component will be described.

[0013] [Polyethylene (A)] The polyethylene (A) used in the present invention is an ethylene polymer composition containing a component (a-1) composed of an ultra-high molecular weight ethylene-based polymer having an intrinsic viscosity [η] measured in a decalin solvent at 135 °C in the range of 10 to 40 dl / g, and a component (a-2) composed of a low molecular weight to high molecular weight ethylene-based polymer having an intrinsic viscosity [η] measured in a decalin solvent at 135 °C in the range of 0.1 to 5 dl / g. Note that the polyethylene (A) is different from the modified polyolefin resin (C) described later.

[0014] When the total amount of the component (a-1) and the component (a-2) is 100% by mass, the content of the component (a-1) is 5 to 75% by mass, preferably 7 to 60% by mass, more preferably 10 to 45% by mass, and the content of the component (a-2) is 95 to 25% by mass, preferably 93 to 40% by mass, more preferably 90 to 55% by mass. By the content ratio of the component (a-1) and the component (a-2) being within the above range, the removability of the residue inside the molding machine can be improved.

[0015] The density of the polyethylene (A) (conforming to ASTM D1505) is 930 to 980 kg / m 3, preferably 940 to 978 kg / m 3 , more preferably 950 to 976 kg / m 3 When the density of the polyethylene (A) is within the above range, it is possible to improve the removability of residues inside the molding machine.

[0016] The polyethylene (A) has an intrinsic viscosity [η] of 1 to 35 dL / g, preferably 2 to 30 dL / g, and more preferably 3 to 25 dL / g, as measured in decalin solvent at 135° C. When the intrinsic viscosity [η] of the polyethylene (A) is within the above range, it is possible to improve the removability of residues inside the molding machine.

[0017] <Component (a-1)> Component (a-1) is an ultra-high molecular weight ethylene polymer having an intrinsic viscosity [η] in the range of 10 to 40 dL / g, preferably 15 to 38 dL / g, and more preferably 20 to 35 dL / g. By having the intrinsic viscosity [η] of component (a-1) in the above range, it is possible to improve the removability of residues inside the molding machine.

[0018] Component (a-1) is a homopolymer of ethylene or a copolymer of ethylene and an α-olefin such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, or 3-methyl-1-pentene. Of these, it is preferable to use a homopolymer of ethylene or a copolymer of ethylene and the above α-olefins, which is composed mainly of ethylene, and an ethylene homopolymer is particularly preferable.

[0019] <Component (a-2)> Component (a-2) is a low- to high-molecular-weight ethylene polymer having an intrinsic viscosity [η] of 0.1 to 5 dL / g, preferably 0.2 to 4 dL / g, and more preferably 0.3 to 3 dL / g. By having the intrinsic viscosity [η] of component (a-2) within this range, it is possible to improve the removability of residues inside the molding machine.

[0020] Component (a-2) is an ethylene homopolymer or a copolymer of ethylene and an α-olefin. The α-olefin constituting the copolymer is a linear or branched α-olefin having 3 to 20 carbon atoms, specifically propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 3,4-dimethyl-1-pentene, 4-methyl-1-hexene, 3-ethyl-1-pentene, 3-ethyl-4-methyl-1-pentene, 3,4-dimethyl-1-hexene, 4-methyl-1-heptene, 3,4-dimethyl-1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Of these, propylene and 1-butene are preferably used.

[0021] Component (a-2) is preferably an ethylene-α-olefin copolymer composed mainly of ethylene, more preferably having an ethylene content of 60 mol % or more, and even more preferably having an ethylene content of 80 mol % or more.

[0022] <Polyethylene (A) content> When the entire molding machine cleaner of the present invention is taken as 100% by mass, the content of polyethylene (A) is preferably 47.4 to 98.9% by mass, more preferably 48.0 to 90.0% by mass. When the total amount of polyethylene (A) and inorganic filler (B) is taken as 100% by mass, the content of polyethylene (A) is preferably 60 to 99.9% by mass, more preferably 62 to 90% by mass. When the content of polyethylene (A) satisfies the above conditions, a cleaner with high detergency can be obtained.

[0023] <Method for producing polyethylene (A)> The method for producing the polyethylene (A) is not particularly limited, and for example, the polyethylene (A) can be produced by mixing the previously obtained components (a-1) and (a-2) described above. Preferred embodiments include the following methods (M-1) and (M-2).

[0024] (M-1) A method of producing the component (a-1) and the component (a-2) in advance in the presence of a known olefin polymerization catalyst, and then mixing or kneading them. (M-2) A method for producing the compound by a multi-stage polymerization method comprising at least two steps: a first step of producing component (a-1) in the presence of a known olefin polymerization catalyst; and a second step of producing component (a-2).

[0025] In this case, the olefin such as ethylene used in the polymerization can be any of the various olefins described in the above items of component (a-1) and component (a-2) without any restrictions.

[0026] Any known olefin polymerization catalyst can be used without any particular limitation, as long as it can produce the above-mentioned components (a-1) and (a-2). Specific examples include Ziegler-Natta catalysts made of titanium tetrachloride or titanium trichloride, supported solid titanium catalysts in which titanium is supported on a support such as magnesium, metallocene catalysts, and post-metallocene catalysts.

[0027] Among the above-mentioned methods for producing the polyethylene (A), the method of multi-stage polymerization as shown in (M-2) is preferably used because it allows the component (a-1) to be finely dispersed in the component (a-2) to give a homogeneous ethylene polymer composition (A).

[0028] The multi-stage polymerization method can be carried out in the same manner as the polymerization method described in JP-A-1-129047, for example.

[0029] [Inorganic filler (B)] The inorganic filler (B) used in the present invention is not particularly limited as long as it does not impair the effects of the present invention, and known inorganic fillers can be used. Preferred examples include glass fiber, wollastonite, and calcium carbonate, which can improve the cleaning properties of the detergent as well as the heat resistance and rigidity of the detergent. These may be used alone or in combination of two or more.

[0030] When the entire molding machine cleaner of the present invention is taken as 100% by mass, the content of the inorganic filler (B) is preferably 0.09 to 31.6% by mass, more preferably 7.0 to 31.0% by mass. Furthermore, when the total amount of the polyethylene (A) and the inorganic filler (B) is taken as 100% by mass, the content of the inorganic filler (B) is preferably 0.1 to 40% by mass, more preferably 10 to 38% by mass. When the content of the inorganic filler (B) satisfies the above conditions, a cleaner with high detergency can be obtained.

[0031] [Modified polyethylene (C)] The modified polyethylene (C) used in the present invention functions as a compatibilizer for the polyethylene (A) and the inorganic filler (B). The modified polyethylene (C) is a polymer containing structural units derived from ethylene as the main component and structural units having functional groups containing heteroatoms (hereinafter simply referred to as "functional groups") in an amount of preferably 0.1 to 10 mass%, more preferably 0.5 to 5 mass%. This amount can be determined, for example, by the method described in paragraphs

[0067] to

[0071] of WO 2015 / 011935.

[0032] Examples of the functional group include a carboxylic acid group (including a carboxylic anhydride group), an ester group, an ether group, an aldehyde group, and a ketone group. A structural unit having a functional group can be introduced, for example, by subjecting an olefin polymer to a modification reaction.

[0033] The modified polyethylene (C) is preferably an ethylene polymer modified with an acid or an acid anhydride, more particularly an ethylene polymer modified with an unsaturated compound having at least one group selected from a carboxyl group and an acid anhydride group.

[0034] Specific examples of the unsaturated compound include unsaturated carboxylic acids or unsaturated dicarboxylic acids such as acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, and endo-cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (Nadic Acid™), as well as derivatives thereof such as acid halides, amides, imides, acid anhydrides, and esters. Among these, unsaturated dicarboxylic acids or their acid anhydrides are preferred, with maleic acid, Nadic acid, and their acid anhydrides being more preferred, and maleic anhydride being particularly preferred. Maleic anhydride has a relatively high reactivity with the ethylene polymer before modification, is less likely to polymerize with itself, and tends to have a stable basic structure, offering various advantages such as the ability to obtain modified polyethylene of consistent quality.

[0035] An example of a method for producing the modified polyethylene (C) is a method in which an unmodified ethylene polymer is graft-modified with a modifying agent (for example, an unsaturated carboxylic acid and its derivatives).

[0036] The graft modification of polyethylene can be carried out by a known method, for example, by dissolving polyethylene in an organic solvent, adding an unsaturated carboxylic acid or a derivative thereof, a radical initiator, etc. to the resulting solution, and reacting the mixture at a temperature of preferably 60 to 350°C, more preferably 80 to 190°C, for preferably 0.5 to 15 hours, more preferably 1 to 10 hours.

[0037] Examples of organic solvents that dissolve polyethylene include aromatic hydrocarbon solvents such as benzene, toluene, and xylene, and aliphatic hydrocarbon solvents such as pentane, hexane, and heptane.

[0038] Another example of a method for graft-modifying polyethylene is to react polyethylene with a modifier (e.g., an unsaturated carboxylic acid or its derivative) using a radical initiator in the absence of a solvent in an extruder, etc. In this case, the reaction temperature is usually above the melting point of the polyolefin, e.g., 100 to 350°C, and the reaction time is usually 0.5 to 10 minutes.

[0039] Examples of the radical initiator include known radical initiators such as dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and 1,4-bis(t-butylperoxyisopropyl)benzene. The radical initiator is preferably used in an amount of 0.001 to 1 part by mass per 100 parts by mass of the polyolefin before modification.

[0040] When the entire molding machine cleaner of the present invention is taken as 100% by mass, the content of the modified polyethylene (C) is preferably 0.5 to 10% by mass, more preferably 1 to 8% by mass. When the content of the modified polyethylene (C) is within this range, the compatibility between the polyethylene (A) and the inorganic filler (B) is improved, and a cleaner with high detergency and ease of replacement can be obtained.

[0041] [Surfactant (D)] The surfactant (D) used in the present invention is not particularly limited, and cationic surfactants, anionic surfactants, zwitterionic surfactants, nonionic surfactants, etc. can be used.

[0042] Examples of cationic surfactants include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.

[0043] Examples of anionic surfactants include alkylbenzenesulfonates, alkylnaphthalenesulfonates, alkanesulfonates, alkyl phosphates, polyoxyethylene alkyl sulfates, and polyoxyethylene alkylphenyl ether sulfates.

[0044] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxysorbitan fatty acid esters, polyoxyethylene alkylamines, glycerin fatty acid esters, and oxyethylene-oxypropylene block polymers.

[0045] Examples of the zwitterionic surfactant include phosphate ester surfactants and lauryl dimethylamine oxide.

[0046] Among the above, nonionic surfactants are preferred from the viewpoint of further improving the ease of replacement of the detergent.

[0047] When the entire molding machine cleaner of the present invention is taken as 100% by mass, the content of surfactant (D) is preferably 0.5 to 10% by mass, more preferably 1 to 8% by mass. When the content of surfactant (D) is within the above range, a cleaner with excellent ease of replacement can be obtained.

[0048] [Metal soap (E)] The metal soap (E) used in the present invention is not particularly limited, but examples thereof include metal salts of carboxylic acids having 12 to 30 carbon atoms, such as calcium stearate, zinc stearate, magnesium stearate, barium stearate, zinc 12-hydroxystearate, zinc stearylphosphate, calcium laurate, barium laurate, zinc laurate, calcium ricinoleate, barium ricinoleate, and zinc ricinoleate.

[0049] When the entire molding machine cleaner of the present invention is taken as 100% by mass, the content of the metal soap (E) is preferably 0.01 to 1.0% by mass, more preferably 0.05 to 0.9% by mass. When the content of the metal soap (E) is within the above range, it functions as a lubricant, thereby providing a cleaner with excellent ease of replacement.

[0050] [Other ingredients] The molding machine cleaner of the present invention may contain optional components other than the above-mentioned components (A) to (E) as long as the effects of the present invention are not impaired. Examples of such optional components include thermoplastic resins such as other polyolefin resins, and resin additives (e.g., stabilizers such as heat stabilizers and weather stabilizers, crosslinking agents, crosslinking aids, antistatic agents, slip agents, antiblocking agents, antifogging agents, lubricants, dyes, pigments, fillers, mineral oil-based softeners, petroleum resins, waxes, etc.).

[0051] [Manufacturing method of molding machine cleaner] The molding machine cleaner of the present invention can be produced by melt-kneading the above-mentioned components. Melt-kneading can be carried out by a known method.

[0052] The melt flow rate (MFR; conforming to JIS K7210-1:2014; measurement temperature 190°C; load 10 kgf) of the obtained molding machine detergent is preferably 0.1 to 20 g / 10 min, more preferably 1 to 10 g / 10 min. By having the MFR of the molding machine detergent within the above range, a detergent with high detergency can be obtained.

[0053] [How to use molding machine cleaner] The method of using the molding machine cleaner of the present invention is not particularly limited, and known methods can be used. For example, the cleaner is charged into a molding machine, and a normal molding operation (cleaning operation) is performed multiple times as necessary to remove residues from the inside of the molding machine. After such a cleaning operation, a molding operation (replacement work) using a molding material such as a resin to be used in the next molding operation is performed multiple times as necessary to discharge the cleaning agent remaining inside the molding machine.

[0054] There are no particular limitations on the molding machine that can be used, and a wide range of known injection molding machines, extrusion molding machines, etc. can be used. [Example]

[0055] The present invention will be explained in more detail below based on examples, but the present invention is not limited to these examples in any way.

[0056] [Method of measuring physical properties] The physical properties of the polymers and molding machine cleaners used in the following examples and comparative examples were determined by the following methods.

[0057] (1) Intrinsic viscosity [η] Measurements were taken at 135°C in decalin solvent. (2) Density Measurement was performed in accordance with ASTM D1505. (3) MFR Measurements were performed in accordance with JIS K7210-1:2014 at a temperature of 190°C and a load of 10 kgf.

[0058] [Each ingredient] The components used in the examples and comparative examples are as follows: <Polyethylene (A)> A-1: Polyethylene (A-1) obtained by the following method

[0059] (1) Preparation of catalyst A 10-liter reactor equipped with a stirrer and thoroughly purged with nitrogen was charged with 4.0 liters of purified hexane and 95 g of anhydrous magnesium chloride, and 350 ml of ethanol was added dropwise at room temperature over two hours with stirring, followed by mixing at room temperature for approximately one hour. Next, 330 ml of diethylaluminum chloride was added dropwise over two hours, and the mixture was mixed at room temperature for approximately one hour after the dropwise addition. Then, 1.3 liters of titanium tetrachloride was added dropwise over one hour, and the mixture was reacted at 80°C for one hour.

[0060] After the reaction was completed, the solid portion was separated using a filter and washed twice with purified hexane to obtain a solid titanium catalyst component. The titanium content of the titanium catalyst component was 6.8% by mass, the magnesium content was 15% by mass, and the chlorine content was 60% by mass. Furthermore, when this solid catalyst component was observed under an optical microscope at 390x magnification, it was observed to be an aggregate of multiple layers of fine solid particles of approximately 1 μm.

[0061] (2) Polyethylene production After 12 L of purified n-decane was added to a 24 L autoclave that had been thoroughly purged with nitrogen, the autoclave was heated to 50°C, and 12 mmol of triethylaluminum and 0.12 mmol of the solid titanium catalyst component (calculated as titanium atoms) were added at the same temperature. The catalyst charging port was then closed, and the internal pressure of the autoclave was reduced to 3.8 kg / cm. 2 Ethylene was introduced to a pressure of 4.0 kg / cm 2 to carry out the first-stage polymerization. The polymerization temperature was maintained at 45-46°C. 45 minutes after the introduction of ethylene, the pressure was quickly released, and when atmospheric pressure was reached, hydrogen was introduced at 5.0 kg / cm 2 2 G was introduced, and ethylene was further introduced at 3.0 kg / cm 2 · G introduced and total pressure 8.0 kg / cm 2 The polymerization temperature was raised to 80°C and the second stage polymerization was carried out. The second stage polymerization time was 490 minutes. After the polymerization was completed, the temperature was lowered and a solid white polymer was separated and dried. The yield of the obtained polyethylene (A-1) was 3485 g, the intrinsic viscosity [η] was 5.73 dl / g and the density was 970 kg / m 3 It was.

[0062] On the other hand, when only the first stage polymerization was separately carried out under the same conditions, the yield of ultra-high molecular weight polyethylene (ethylene homopolymer) [(a-1)-1] obtained was 595 g, and the intrinsic viscosity [η] was 28.0 dL / g. From this, the content of ultra-high molecular weight polyethylene [(a-1)-1] was estimated to be 17.1 mass%. From this, the intrinsic viscosity [η] of the low- to high-molecular weight polyethylene [(a-2)-1] produced in the second stage was calculated to be 1.14 dL / g using the following formula:

[0063] [η]all=[η][(a-1)-1]×[(a-1)-1]mass%+[η][(a-2)-1]×[(a-2)-1]mass% [η]all: Intrinsic viscosity [η] (dl / g) of the entire polymer [polyethylene (A)] [η] [(a-1)-1]: Intrinsic viscosity [η] (dl / g) of [(a-1)-1] [(a-1)-1]: mass% [(a-1)-1] content (mass%) [η] [(a-2)-1]: Intrinsic viscosity of [(a-2)-1] (dl / g) [(a-2)-1] mass%: [(a-2)-1] content (mass%)

[0064] <Inorganic filler (B)> B-1: Glass fiber chopped strand (Nippon Electric Glass Co., Ltd. "ESC 03 T480H") B-2: Wollastonite (NYCO Minerals "NYGLOS 12")

[0065] <Modified polyethylene (C)> C-1: Modified polyethylene (C-1) obtained by the following method 100 parts by mass of ethylene homopolymer (Prime Polymer "2200J", MFR = 5.2 g / 10 min), 2.0 parts by mass of maleic anhydride, and 0.35 parts by mass of organic peroxide [NOF Corporation "Perhexyne-25B"] were mixed in a Hexchel mixer, and the resulting mixture was melt-grafted in a 100 mmφ twin-screw extruder set to 270°C for a kneading time of approximately 1 minute 30 seconds to obtain modified polyethylene (C). The maleic anhydride graft content of the resulting modified polyethylene (C) was measured by IR analysis to be 1.0% by mass.

[0066] <Surfactant (D)> D-1: Nonionic surfactant (Marubishi Oil Chemical Industry's "Denon 331-L")

[0067] <Metal soap (E)> E-1: Magnesium stearate ("Magnesium Stearate GP" manufactured by Nippon Oil & Fats)

[0068] [Examples 1 to 2 and Comparative Examples 1 to 5] <Manufacturing of molding machine cleaners> Polyethylene (A), modified polyethylene (C), surfactant (D), and metal soap (E) were dry-blended in the amounts shown in Table 1 below, and then charged into a twin-screw extruder (manufactured by Toshiba Corporation, φ=26 mm, L / D=64, cylinder temperature: 230°C), and inorganic filler (B) was added by side feeding from near cylinder C11, followed by melt-kneading to obtain a molding machine detergent. The MFR of the resulting molding machine detergent was measured.

[0069] [Table 1]

[0070] The resulting molding machine cleaners were evaluated for cleaning ability and residue (ease of replacement) using the methods described below. The results are shown in Table 2. The molding machine used to evaluate cleaning ability and residue was an injection molding machine "J110-AD" manufactured by The Japan Steel Works, Ltd., and the operating conditions were as follows: (Operating conditions) Cylinder temperature (℃): 50 / 220 / 280 / 280 / 280 / 280 / 280 Injection pressure (kg / cm 2 ):600 Screw rotation speed (rpm): 80 Mold temperature (℃): Water cooling (60℃)

[0071] <Cleaning ability> After filling a molding machine with black-colored polyethylene (HDPE) molding material, the injection molding machine was emptied by ejecting it using an injection operation. Next, the resulting molding machine cleaner was added to the molding machine, and a purging operation (cleaning injection operation) was performed. The number of purgings and the amount of molding machine cleaner used were measured until the absence of residual residue (black stains) was visually confirmed.

[0072] <Residuality> After measuring the cleanability, the molding machine was emptied by ejecting all residues through an injection operation, and then polycarbonate was filled into the molding machine to prepare dumbbell-shaped tensile test specimens. The number of shots and the amount of polycarbonate (PC) used were measured until the absence of residues (white spots of the molding machine cleaner) was visually confirmed.

[0073] [Table 2]

Claims

1. A molding machine cleaner, comprising: The molding machine cleaner contains polyethylene (A), an inorganic filler (B), a modified polyethylene (C), a surfactant (D), and a metal soap (E), the polyethylene (A) is an ethylene polymer composition comprising: 5 to 75% by mass of a component (a-1) consisting of an ultra-high molecular weight ethylene polymer having an intrinsic viscosity [η] measured in decalin at 135°C in the range of 10 to 40 dl / g; and 95 to 25% by mass of a component (a-2) consisting of a low- to high-molecular weight ethylene polymer having an intrinsic viscosity [η] measured in decalin at 135°C in the range of 0.1 to 5 dl / g (wherein the total amount of component (a-1) and component (a-2) is taken as 100% by mass); The density of the polyethylene (A) (in accordance with ASTM D1505) is 930 to 980 kg / m 3 and the intrinsic viscosity [η] measured in decalin solvent at 135°C is 1 to 35 dl / g; When the entire molding machine detergent is taken as 100% by mass, the content of the polyethylene (A) is 47.4 to 98.9% by mass, The content of the inorganic filler (B) is 0.09 to 31.6 mass %, the content of the modified polyethylene (C) is 0.5 to 10% by mass, The content of the surfactant (D) is 0.5 to 10 mass %, The molding machine cleaner, wherein the content of the metal soap (E) is 0.01 to 1.0 mass%.

2. 2. The molding machine cleaning agent according to claim 1, wherein the content of the polyethylene (A) is 60 to 99.9 mass% and the content of the inorganic filler (B) is 0.1 to 40 mass%, where the total amount of the polyethylene (A) and the inorganic filler (B) is 100 mass%.

3. 3. The molding machine cleaner according to claim 1, wherein the inorganic filler (B) is at least one selected from the group consisting of glass fiber, wollastonite, and calcium carbonate.

4. The molding machine cleaning agent according to any one of claims 1 to 3, wherein the modified polyethylene (C) is an ethylene polymer modified with an acid or an acid anhydride.

5. The molding machine cleaning agent according to any one of claims 1 to 4, wherein the surfactant (D) is a nonionic surfactant.

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