JP7187726B1 - Detergent for resin processing machine, method for producing the same, and method for cleaning inside of resin processing machine - Google Patents

Abstract

Kind Code: A1 An object of the present invention is to provide a cleaning agent for resin processing machines which uses resin film/sheet offcuts as a raw material and is excellent in quality, workability and cleaning performance. The method includes a pulverized body obtained by subjecting a raw material including resin film/sheet offcuts to a process selected from the group consisting of crimping, semi-melting, and melt-kneading, and the processing temperature of the process is A detergent for resin processing machines, characterized by having a temperature of 280°C or less. [Selection figure] None

Description

TECHNICAL FIELD The present invention relates to a cleaning agent for resin processing machines, a method for producing the same, and a method for cleaning the inside of resin processing machines.

In recent years, due to the growing interest in environmental problems surrounding plastics and the shift to a circular economy, efforts to reduce the amount of plastic waste and to recycle have been promoted.
In the production process of resin film and sheet products, scraps (trimming selvages) generated by cutting, defective original fabrics, and scraps such as defective products are generated. It is required to take an appropriate disposal method in consideration of the load. On the other hand, material recycling is generally practiced as a means of effectively utilizing resin film and sheet offcuts. Various methods have been proposed, such as cascade recycling for purpose.

As the use of recycled resins for various plastic products progresses, the use of recycled resins as raw materials for detergents for resin processing machines, which use resin as the main raw material, is also under study. For example, Patent Literature 1 discloses an example in which pulverized crosslinked polyethylene film is used as a raw material for a purging agent.

JP-A-3-99822

In general, unlike bottle moldings and the like, when resin film or sheet offcuts are used as raw materials, there is a problem that they cannot be used as cleaning agents because they have a low bulk density if they are only finely pulverized.
In this regard, Patent Literature 1 describes a purge agent obtained by melt-kneading a pulverized crosslinked polyethylene film with other additive components at 300°C. However, due to the progress of thermal deterioration of the resin due to high temperature heating during processing, yellowing and black spots occur in the cleaning agent pellets, resulting in deterioration of quality and smoke during processing, which reduces workability. rice field. In addition, there is also the problem that the expected cleaning effect cannot be obtained due to the decrease in molecular weight and viscosity associated with thermal deterioration.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cleaning agent for resin processing machines which is excellent in quality, workability and cleaning performance and which uses resin film/sheet offcuts as raw materials.

As a result of intensive studies to solve the above problems, the present inventors have found that the processing temperature of these processing steps includes pulverized bodies obtained by crimping, semi-melting, or melt-kneading resin film/sheet offcuts. is 280° C. or lower, the above problems can be solved, and the present invention has been completed.

That is, the present invention is as shown below.
[1]
A weight average molecular weight of 50,000 or more,
A pulverized body obtained by performing processing selected from the group consisting of crimping, semi-melting, and melt-kneading on a raw material containing resin film/sheet scraps mainly composed of polyolefin resin or styrene resin. including
The processing is performed without heating or with heating within a temperature range of 280 ° C. or less in the case of crimping, and without heating or with heating within a temperature range of 280 ° C. or less in the case of semi-melting. In the case of melt kneading, it is performed by heating within the temperature range of 160 ° C. or higher and 280 ° C. or lower.
A detergent for resin processing machines characterized by:
[2]
The cleaning agent for resin processing machines according to [1], wherein the pulverized product has a bulk density of 0.10 g/cm ³ or more.
[3]
The cleaning agent for resin processing machines according to [1] or [2], wherein the pulverized body has a maximum length of 2 to 10 mm.
[4 ]
[1] to [ 3 ], wherein the processing is melt-kneading, including melt-kneading the raw material containing the resin film/sheet scraps in an extruder, and the L/D of the extruder is 45 or less. The cleaning agent for resin processing machines according to any one of .
[ 5 ]
The cleaning agent for resin processing machines according to any one of [1] to [ 4 ], which further contains other components and is obtained by melt-kneading or dry-blending the pulverized product and the other components .
[6 ]
The raw material according to any one of [1] to [ 5 ], further comprising at least one additive selected from the group consisting of antioxidants, lubricants, surfactants, plasticizers, and inorganic fillers. Detergent for resin processing machines.
[ 7 ]
A method for producing a cleaning agent for resin processing machines according to any one of [1] to [ 6 ],
Obtaining a pulverized body by performing processing selected from the group consisting of crimping, semi-melting, and melt-kneading on raw materials including resin film and sheet scraps,
The processing is performed without heating or with heating within a temperature range of 280 ° C. or less in the case of crimping, and without heating or with heating within a temperature range of 280 ° C. or less in the case of semi-melting. In the case of melt kneading, it is performed by heating within the temperature range of 160 ° C. or higher and 280 ° C. or lower.
A manufacturing method characterized by:
[ 8 ]
[1] A cleaning method characterized by using the cleaning agent for resin processing machines according to any one of [1] to [ 7 ].

According to the present invention, it is possible to provide a cleaning agent for resin processing machines that uses resin film/sheet offcuts as a raw material and is excellent in quality, workability and cleaning performance.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "this embodiment") for implementing this invention is demonstrated in detail. It should be noted 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.

<Cleaning agents for resin processing machines>
The cleaning agent for resin processing machines of the present embodiment (hereinafter also simply referred to as "cleaning agent") is selected from the group consisting of pressure bonding, semi-melting, and melt-kneading for raw materials including resin film and sheet scraps. It is characterized in that it includes a pulverized body obtained by performing the processing described above, and the processing temperature of the processing is 280° C. or less.

[Pulverized body]
The pulverized body contained in the cleaning agent of the present embodiment is obtained by crimping, semi-melting, or melt-kneading raw materials including resin film/sheet scraps. The raw material containing the resin film/sheet offcuts may contain an additive, which will be described later, in addition to the resin film/sheet offcuts.

As a method of crimping raw materials containing resin film/sheet scraps, for example, a method of stacking a plurality of raw materials containing resin film/sheet scraps and applying pressure with a roll or the like to bond them together, or a method of bonding a single film/sheet. For example, a method of compressing raw materials including mill ends while collecting them can be used.
When crimping, in order to increase the binding property of the resin film/sheet scraps, heating by an external heat source may be performed during crimping as long as the processing temperature is within the range described later, but from the viewpoint of suppressing thermal deterioration of the resin. Therefore, non-heating is desirable.
A pulverized body can be obtained by cutting the obtained crimped product into a predetermined size with a rotating blade or the like.

As a method for semi-melting raw materials containing resin film/sheet scraps, for example, raw materials containing resin film/sheet scraps (premixed if additives are included) are put into an extruder having a screw. Alternatively, a semi-molten product can be obtained by semi-melting the resin by shearing heat generated by the resin due to friction caused by rotation of the screw.
When the resin is semi-melted, it may be heated by an external heat source as long as it is within the range of the processing temperature described later. Also, the processing temperature may be adjusted by a method of circulating a coolant inside the machine.
Note that semi-melting refers to making the resin gel at a temperature below its melting point.
A pulverized body can be obtained by cutting the obtained semi-molten material with a pelletizer or the like while extruding it. As a cutting method, a method such as strand cutting, hot cutting, or underwater cutting can be selected depending on the workability of the raw material including the resin film/sheet offcuts.

As a method for melt-kneading raw materials containing resin film/sheet scraps, the raw materials containing resin film/sheet scraps (premixed if additives are included) are kneaded while being heated using a melt-kneading device. methods and the like can be used.
The method of supplying raw materials including resin film/sheet scraps is not particularly limited. Examples include a method of supplying to a melt-kneading device with a feeder equipped with an agitator, a method of directly collecting and feeding raw materials including resin film/sheet offcuts, and using a device in which a offcut crushing unit and extrusion unit are integrated. .
The melt-kneading apparatus is not particularly limited, and known kneaders can be used, and examples thereof include extruders including single-screw extruders and twin-screw extruders, kneaders, co-kneaders, and Banbury mixers. At this time, the temperature of the heater is set within the processing temperature range described later. An extruder is particularly preferred from the viewpoint of being able to sufficiently knead the resin. In that case, the L/D of the extruder used is not particularly limited, but from the viewpoint of suppressing heat history, it is preferably 45 or less, more preferably 40 or less. Also, from the viewpoint of sufficiently melting the raw material, L/D is preferably 18 or more, more preferably 20 or more. Here, L/D is the ratio of screw length (L) to screw diameter (D).
A pulverized product can be obtained by cutting the obtained melt-kneaded product and molding it into a pellet shape. As a method for cutting the melt-kneaded product, a method such as strand cutting, hot cutting, or underwater cutting can be selected depending on the workability of the raw material including the resin film/sheet offcuts.
From the viewpoint of quality maintenance, during melt-kneading, open degassing to remove degassing from the open port (vent) at normal pressure, or reduce the pressure as necessary to remove degassing from the open port (vent). Degassing under reduced pressure is desirable. It is desirable to shorten the residence time of the molten resin in the melt-kneading apparatus as much as possible.

In crimping, semi-melting, and melt-kneading, resin film/sheet scraps and additives are mixed with commonly used equipment such as premixing equipment such as tumbler blenders, ribbon blenders, and super mixers. A feeder or the like can be used.

The processing temperature when processing raw materials including resin film/sheet scraps into pulverized bodies is 280° C. or lower, preferably 260° C. or lower, more preferably 240° C. in any of crimping, semi-melting, and melt-kneading. °C or less, more preferably 220°C or less. When the processing temperature is within the above range, the thermal deterioration of the resin film/sheet offcuts is suppressed, and the physical properties of the resin film/sheet such as molecular weight and viscosity can be maintained, so the quality and cleaning performance tend to be excellent. The lower limit of the processing temperature is not particularly limited, and as described above, it is desirable to carry out compression bonding and semi-melting without heating. In the melt-kneading, the temperature is preferably 160° C. or higher, more preferably 170° C. or higher, and still more preferably 180° C. or higher, from the viewpoint of sufficiently melting the raw materials.
The processing temperature can be controlled within the above range by adjusting various processing conditions (supply speed of resin film/sheet offcuts, shear rate, screw rotation speed, heating temperature setting, cooling) and the like.

[[Resin film and sheet offcuts]]
There are no particular restrictions on the resin film/sheet offcuts that are used as raw materials for the pulverized product. etc.
The resin film/sheet offcuts may be used singly or in combination of two or more.

The type of resin film/sheet offcuts is not particularly limited, but examples thereof include films/sheets containing polyolefin-based resin as a main component. It may be a combination of species or more. Films and sheets containing polyolefin resin as a main component may also contain resins other than polyolefin resins, such as nylon and polyethylene terephthalate, as long as the performance of the present invention is not impaired.
In addition, a styrene resin (a polystyrene resin, or a copolymer of styrene and one or more other monomers with a styrene content of 50% by mass or more) is the main component. Films and sheets containing as
The term “main component” refers to a component contained at a rate of more than 50% by mass, preferably at least 60% by mass, more preferably at least 70% by mass of the resin film/sheet.

Examples of polyolefin-based resins include polyethylene-based resins and polypropylene-based resins.
A polyethylene resin is a homopolymer of ethylene, or a copolymer of ethylene and one or more other monomers, in which the content of structural units derived from ethylene is 50% by mass or more. indicates The polypropylene-based resin is a homopolymer of propylene, or a copolymer of propylene and one or more other monomers, in which the content of structural units derived from propylene is 50% by mass or more. of the

Examples of the polyethylene-based resin include polyethylene, ethylene-α-olefin copolymer, and the like. Specifically, high-density polyethylene, low-density polyethylene, linear low-density Polyethylene etc. are mentioned. Furthermore, ultra-high molecular weight polyethylene resins, crosslinked polyethylene resins, and the like are also included, and when these are used, the effect of improving the cleaning performance can be obtained by improving the viscosity of the cleaning composition.
Here, the ultra-high molecular weight polyethylene resin refers to a polyethylene resin having a viscosity average molecular weight of 300,000 or more. From the viewpoint of cleaning performance, the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is preferably 300,000 or more, more preferably 350,000 or more, and still more preferably 400,000 or more.
Examples of crosslinked polyethylene resins include crosslinked high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene/vinyl acetate copolymer, chlorinated polyethylene, ethylene/ethyl acrylate copolymer, and the like. The cross-linking method is not particularly limited, and examples thereof include peroxide cross-linking, electron beam cross-linking, and silane cross-linking.

Examples of the polypropylene-based resin include propylene homopolymers, random copolymers, block copolymers, and the like, and any of them can be suitably used.

The structure of the resin film/sheet offcuts is not particularly limited, and multi-layer film/sheet offcuts and the like can also be used.

Ingredients added to resin film and sheet scraps to improve moldability and add functionality include lubricants, anti-fogging agents, nucleating agents, antistatic agents, antioxidants, stabilizers, and surfactants. , a plasticizer, a cross-linking accelerator, an antiblocking agent, an inorganic filler, and other additives. When used as a resin raw material for cleaning agents, these additives may contribute to the improvement of the cleaning effect as active ingredients, which can be an advantage of using resin film/sheet scraps as raw materials.

The content of the resin film/sheet offcuts is not particularly limited, but from the viewpoint of environmental consideration and cost reduction effect, it is preferably 20% by mass or more, more preferably 30% by mass or more, based on 100% by mass of the cleaning agent. , more preferably 40% by mass or more.

[[Additive]]
The raw material of the pulverized body may contain additives in addition to the resin film/sheet offcuts.
Examples of additives include antioxidants, lubricants, surfactants, plasticizers, inorganic fillers, inorganic foaming agents, virgin thermoplastic resins that are not recycled, and ultrahigh molecular weight resins. Additives may be used singly or in combination of two or more. Among them, at least one selected from the group consisting of antioxidants, lubricants, surfactants, plasticizers and inorganic fillers is preferable.
By adding an additive, the cleaning agent can be made more suitable for the performance required for the cleaning purpose and application (processing machine to be cleaned, type of resin, etc.).

The total content of additives is not particularly limited, but is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, based on 100% by mass of the detergent.

(Antioxidant)
It is desirable to add an antioxidant to resin film/sheet offcuts because they are subjected to heat history more than virgin resin.
Antioxidants include general antioxidants such as phosphorus antioxidants, hindered phenol antioxidants, and hydroxylamine antioxidants, but are not particularly limited. Specific examples of phosphorus antioxidants include tris(2,4-di-t-butylphenyl) phosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, 2,2' -methylenebis(4,6-di-t-butyl-1-phenyloxy)(2-ethylhexyloxy)phosphite and the like. Specific examples of hindered phenol antioxidants include pentaerythritol tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3-(3,5-di-t -butyl-4-hydroxyphenyl)propionate, 4,4'-butylidenebis(6-t-butyl-m-cresol) and the like. Specific examples of hydroxylamine-based antioxidants include distearylhydroxylamine and the like.
Antioxidants may be used singly or in combination of two or more.

In order to exhibit a sufficient effect of the antioxidant, it is preferable to add 0.01% by mass or more, more preferably 0.05% by mass or more, and 0.1% by mass to 100% by mass of the detergent. % by mass or more is more preferable. Moreover, the content of the antioxidant is preferably less than 3% by mass, more preferably 1.5% by mass or less, and even more preferably 1% by mass or less. When the content of the antioxidant is within the above range, the effect of suppressing the deterioration of the resin in the detergent is obtained, and the decomposition product of the antioxidant itself inhibits other additives (lubricants, etc.). It tends to be less effective.

(Lubricant)
Examples of lubricants include organic acids, organic acid metal salts, organic acid amides, organic acid derivatives such as organic acid esters, various ester waxes, olefin waxes, fluorine-based resins, and mineral oils, but are particularly limited to these. not a thing

As the organic acid, saturated fatty acids having 9 to 28 carbon atoms, unsaturated fatty acids having 9 to 28 carbon atoms, and benzoic acid are preferable. A part of the chain may have a hydroxyl group. In particular, stearic acid, 12-hydroxystearic acid, palmitic acid, myristic acid, and lauric acid are more preferable from the viewpoint of availability and heat resistance. Mixed fatty acids having different alkyl chains may also be used. When the number of carbon atoms is within the above range, there is no problem of gas generation or odor, and the ease of availability and the properties as a lubricant at the interface tend to function well.

The metal in the metal salt of the organic acid is not particularly limited, but includes sodium, potassium, lithium, cesium, magnesium, calcium, aluminum, zinc, iron, cobalt, barium and the like. Among them, lithium, calcium, barium, zinc, and aluminum are preferable because they exhibit the most effective lubricating effect. Among them, metal salts of aluminum and zinc are more preferable because they have low polarity and tend to exhibit external lubricity by bleeding out from the thermoplastic resin. Zinc is particularly preferred.
The hydrocarbon moiety in the metal salt of the organic acid is preferably a saturated fatty acid having 9 to 28 carbon atoms, an unsaturated fatty acid having 9 to 28 carbon atoms, or benzoic acid, as in the organic acid described above. from the viewpoint of stearic acid, 12-hydroxystearic acid, palmitic acid, myristic acid, and lauric acid are more preferred.

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. Among them, fatty acids having 12 to 18 carbon atoms such as lauric acid, myristic acid, palmitic acid, and stearic acid, unsaturated fatty acid amides such as erucic acid, and saturated fatty acid bisamides such as ethylenebisstearic acid amide are readily available. , and more preferably saturated fatty acid bisamide such as ethylenebisstearic acid amide, from the viewpoint of its effect as a lubricant.

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, and polyol esters such as hardened oils. From the standpoints of availability and effectiveness as a lubricant, stearate stearate, glycerin fatty acid ester monoglyceride, and the like are preferred.

Examples of the olefin wax include low-molecular-weight polyolefins, and are not particularly limited, but general low-density or high-density polyethylene, polypropylene, and the like can be used. Those having a weight average molecular weight of about 1,000 to 20,000 and a dropping point of 80 to 180° C. are most likely to exhibit the effect.

Examples of the fluorine-based resin include PTFE, PFA, PVDF, PVDF-based copolymer, ETFE, and PFE, and are expected to have the effect of suppressing resin adhesion to metal surfaces. As for the shape, various shapes such as pellets and powders can be used, but powdery ones are particularly preferable in order to uniformly disperse them during processing. Although the average particle size is not particularly limited, it is preferably 1,000 μm or less.

The mineral oil is an oil obtained by refining petroleum, and is a saturated hydrocarbon oil containing naphthene, isoparaffin, etc., which is also called mineral oil, lubricating oil, liquid paraffin, and the like. Mineral oils with a wide range of viscosities can be used. For example, in the case of liquid paraffin, those with a kinematic viscosity of 50 to 500 mm ² /s as measured by JIS K2283, the Redwood method (Japan Oil Chemists' Association standard oil analysis test method) 2.2.10.4-1996) having a viscosity in the range of 30 to 2000 (seconds) may be used.

The lubricants described above may be used singly or in combination of two or more.

From the viewpoint of cleaning performance, the lubricant preferably has a melting point or softening point of 70°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher.

The lubricant content is preferably 0.1 to 10% by mass, more preferably 0.2 to 10% by mass, and still more preferably 0.5 to 8% by mass based on 100% by mass of the detergent. .

(Surfactant)
Surfactants include anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, and the like.
Examples of anionic active agents include higher fatty acid alkali salts (alpha sulfo fatty acid methyl ester sodium, etc.), alkyl sulfates, alkyl sulfonates, alkylaryl sulfonates, sulfosuccinate salts, and the like.
Examples of cationic activators include higher amine halides, alkylpyridinium halides, quaternary ammonium salts, and the like.
Examples of nonionic active agents include polyethylene glycol alkyl ethers, polyethylene glycol fatty acid esters, sorbitan fatty acid esters, pentaerythritol fatty acid esters (pentaerythritol tetrastearate, etc.), fatty acid monoglycerides, and the like.
An amino acid etc. can be illustrated as an amphoteric surfactant.
Surfactants may be used alone or in combination of two or more.

The content of the surfactant is preferably 0.1 to 10% by mass, more preferably 0.2 to 10% by mass, and still more preferably 0.5 to 8% by mass with respect to 100% by mass of the detergent. is.

(Plasticizer)
The plasticizer is not particularly limited, and includes general plasticizers such as phthalate, adipate, trimellitate, and citrate.
The content of the plasticizer is preferably 0.1 to 10% by mass, more preferably 0.2 to 10% by mass, and still more preferably 0.5 to 8% by mass with respect to 100% by mass of the detergent. be.

(Inorganic filler)
In this specification, the term "inorganic filler" means an inorganic compound other than the inorganic foaming agent described below, and includes both natural products and artificially synthesized products. Specific examples of 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, oxide zinc, alumina, silica, aluminum hydroxide, magnesium hydroxide, zeolite, diatomaceous earth, glass powder, glass spheres, glass fibers, shirasu balloons, and the like.
The content of the inorganic filler is preferably 1 to 70% by mass, more preferably 3 to 60% by mass, still more preferably 5 to 50% by mass, based on 100% by mass of the detergent.

(Inorganic foaming agent)
As used herein, an inorganic foaming agent refers to an inorganic compound that is decomposed by heating to foam, that is, generate gas. Specific examples of inorganic foaming agents include inorganic physical foaming agents such as water, hydrogen carbonates such as sodium hydrogen carbonate and ammonium hydrogen carbonate, carbonates such as sodium carbonate and ammonium carbonate, nitrites such as ammonium nitrite, and borohydrides. Hydrides such as sodium, azide compounds such as calcium azide, light metals such as magnesium and aluminum, combinations of sodium bicarbonate and acids, combinations of hydrogen peroxide and yeast, combinations of aluminum powder and acids, and the like. Inorganic chemical blowing agents are mentioned.
The content of the inorganic foaming agent is preferably 0.1 to 10% by mass, more preferably 0.2 to 10% by mass, and still more preferably 0.5 to 8% by mass with respect to 100% by mass of the detergent. is.

(virgin thermoplastic resin)
Virgin thermoplastic resins are not particularly limited, and include polyolefin resins, styrene resins (polystyrene resins, styrene-acrylonitrile copolymer resins, etc.), polycarbonate resins, polyamide resins, polyester resins, and the like.
The content of the virgin thermoplastic resin is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, still more preferably 30 to 50% by mass, based on 100% by mass of the detergent. The lower the blending ratio of the virgin thermoplastic resin, the greater the cost advantage of using the resin film/sheet offcuts, and the better the recyclability.

(ultra-high molecular weight resin)
In this specification, the ultra high molecular weight resin is a polymer having a molecular weight of 1,000,000 or more, and examples thereof include ethylene-based ultra-high polymers, styrene-acrylonitrile-based ultra-high polymers, and methyl methacrylate-based ultra-high polymers. Among them, ethylene-based ultra-high polymers are preferred. Although the upper limit of the molecular weight is not particularly limited, it is practically preferably 10,000,000 or less.
In addition, the ultrahigh molecular weight resin may be a homopolymer or a copolymer, and in the case of a copolymer, the content of the main component (eg, ethylene, styrene-acrylonitrile copolymer, methyl methacrylate, etc.) must be 50% by mass or more. .
The content of the ultrahigh molecular weight resin is preferably 1 to 30% by mass, more preferably 3 to 25% by mass, still more preferably 5 to 20% by mass, based on 100% by mass of the detergent.

The shape of the pulverized body is not particularly limited, but examples thereof include pellet-like (cylindrical, spherical, planar), flake-like, and powder-like shapes.

As for the size of the pulverized body, the maximum length is preferably 2 to 10 mm, more preferably 3 to 10 mm, still more preferably 3 to 8 mm. When the maximum length is 2 to 10 mm, when the cleaning agent consists of pulverized bodies (the pulverized bodies themselves are used as the cleaning agent), there is a tendency for the screw of the resin processing machine to be cleaned to have good biting properties. It is in. As will be described later, when the cleaning agent contains other components in addition to the pulverized particles and is obtained by dry-blending the pulverized particles and the other ingredients, classification due to differences in shape, etc. In addition to suppressing process defects, even when the cleaning agent is obtained by melt-kneading the pulverized product and other components, it has good biting property into the screw of the melt-kneading device during the melt-kneading. tends to be
The maximum length of the pulverized body is the average value of the maximum length of the distance between two points on the surface of the pulverized body of 50 or more pulverized bodies measured using a vernier caliper or the like. .

The pulverized body preferably has a bulk density of 0.10 g/cm ³ or more, more preferably 0.15 g/cm ³ or more, and still more preferably 0.20 g/cm ³ or more. When the bulk density is 0.10/cm ³ or more, when the pulverized bodies themselves are used as a cleaning agent (the cleaning agent consists of pulverized bodies), the feed to the resin processing machine to be cleaned tends to be stable. . Further, as will be described later, when the cleaning agent contains other components in addition to the pulverized particles and is obtained by dry-blending the pulverized particles and the other ingredients, the classification tends to be suppressed. In addition, when the cleaning agent is obtained by melt-kneading the pulverized product and other components, the feed to the melt-kneading apparatus during the melt-kneading tends to be stable.
The upper limit of the bulk density of the pulverized body is not particularly limited, but it is preferably 0.80 g/cm ³ or less, more preferably 0.75 g/cm ³ or less, and still more preferably 0.70 g/cm ³ or less. is.
The bulk density of the pulverized body shall be measured according to JIS K 7365.

The content of the pulverized body in the cleaning agent is not particularly limited, but from the viewpoint of environmental consideration and cost reduction effect, it is preferably 20 to 100% by mass, more preferably 30 to 90%, based on 100% by mass of the cleaning agent. % by mass, more preferably 50 to 80% by mass.

[Other ingredients]
The cleaning agent of the present embodiment may contain other components in addition to the pulverized bodies. It is possible to make a cleaning agent consisting only of pulverized bodies (use the pulverized bodies as they are as a cleaning agent), but by including other ingredients, the cleaning purpose and application (resin processing machine to be cleaned, resin type, etc.).
Other components include, for example, antioxidants, lubricants, surfactants, plasticizers, inorganic fillers, inorganic foaming agents, virgin thermoplastic resins that are not recycled, ultra-high molecular weight resins, etc. The same additives as those contained in Other components may be used singly or in combination of two or more.

The total content of other components is not particularly limited, but is preferably 80% by mass or less, more preferably 70% by mass or less, and still more preferably 60% by mass or less, based on 100% by mass of the detergent.

The content of each of the other components in 100% by mass of the cleaning agent may be the same as that of each additive contained in the pulverized body described above.
When the detergent contains the same compound as an additive and other components, the total content is preferably within the preferred range of the content of each additive described above. For example, when the antioxidant is contained in the pulverized product as an additive and is also contained in the cleaning agent as another component, the total content of the antioxidant as the additive and the antioxidant as the other component The amount is preferably 0.01% by mass or more and less than 3% by mass with respect to 100% by mass of the cleaning agent.

When the cleaning agent contains other components, the other components are preferably melt-kneaded or dry-blended with the pulverized body.

Examples of the method of melt-kneading the pulverized body and other components include a method of pre-mixing the pulverized body and other components and melt-kneading them using a melt-kneading apparatus.
The melt-kneading apparatus is not particularly limited, and known kneaders can be used, and examples thereof include extruders including single-screw extruders and twin-screw extruders, kneaders, co-kneaders, and Banbury mixers. In particular, an extruder is preferable, and a twin-screw extruder is more preferable, from the viewpoint of sufficiently kneading the resin. The use of a twin-screw extruder tends to stabilize the extrudability and suppress the pulsation of the strand extruded from the extruder.
A pulverized product can be obtained by cutting the obtained melt-kneaded product and molding it into a pellet shape. As a method for cutting the melt-kneaded product, a method such as strand cutting, hot cutting, or underwater cutting can be selected depending on the workability of the raw material including the resin film/sheet offcuts.
For mixing the pulverized material and other components, commonly used devices such as premixing devices such as tumbler blenders, ribbon blenders, and super mixers, gravimetric feeders, and the like may be used.
In addition, the melt-kneading temperature (for example, the set temperature of the cylinder when melt-kneading with an extruder) is preferably set to 280 ° C. or less, more preferably 260 ° C. or less, from the viewpoint of suppressing heat history. °C or less is more preferable. Although the lower limit of the melt-kneading temperature is not particularly limited, it is preferably set to 160° C. or higher, more preferably 170° C. or higher, and even more preferably 180° C. or higher, from the viewpoint of sufficiently melting the raw materials.
As a method for cutting the melt-kneaded product, a method such as strand cutting, hot cutting, or underwater cutting can be selected depending on the workability of the cleaning agent composed of the pulverized product.
From the viewpoint of quality maintenance, during melt-kneading, open degassing to remove degassing from the open port (vent) at normal pressure, or reduce the pressure as necessary to remove degassing from the open port (vent). Degassing under reduced pressure is desirable. It is desirable to shorten the residence time of the molten resin in the melt-kneading apparatus as much as possible.

On the other hand, as a method of dry-blending the pulverized body and other components, for example, there is a method of mixing the pulverized body and other components with a mixing device such as a tumbler blender, a ribbon blender, a super mixer, or the like for a certain period of time.
The other components to be added by dry blending are not particularly limited, but are preferably virgin thermoplastic resin pellets or a masterbatch in which components effective for washing are granulated in advance.

The weight average molecular weight of the detergent for resin processing machines is preferably 50,000 or more, more preferably 80,000 or more, and even more preferably 100,000 or more. When the weight-average molecular weight of the cleaning agent is within the above range, thermal deterioration of the resin film/sheet offcuts is suppressed, so that excellent cleaning performance tends to be exhibited. There are no particular restrictions on the upper limit of the weight average molecular weight of the detergent.
The weight-average molecular weight is a value measured using gel permeation chromatography (GPC), and specifically, it can be determined by the method described in Examples below. The eluent to be used is not particularly limited as long as it dissolves the target resin.

[Shape of detergent for resin processing machines]
The shape of the cleaning agent of the present embodiment is not particularly limited as long as it does not impair the effects of the present invention.

[Method for producing cleaning agent for resin processing machines]
As described above, the method for producing a cleaning agent of the present embodiment is such that a raw material including resin film/sheet scraps is subjected to a process selected from the group consisting of crimping, semi-melting, and melt-kneading to obtain a pulverized body. and the processing temperature of the processing is 280° C. or less.
Moreover, as described above, the method for producing the cleaning agent of the present embodiment may include melt-kneading or dry-blending the pulverized product and other components.

[Method for cleaning the inside of the resin processing machine]
The method for cleaning the interior of the resin processing machine of the present embodiment is characterized by using the cleaning agent for the resin processing machine of the present embodiment described above.
Examples of resin processing machines that can be cleaned using the cleaning agent for resin processing machines of the present embodiment include injection molding machines, extruders, and the like, and particularly resin processing machines that handle thermoplastic resins. It is not limited.

EXAMPLES 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 the gist thereof is not exceeded.

Components used in Examples and Comparative Examples are as follows.

<Resin film/sheet offcuts>
(A-1) Polyethylene film scraps (PE) (weight average molecular weight: 250,000)
(A-2) OPP packaging sheet offcuts (PP) (weight average molecular weight: 200,000)
(A-3) Ultra-high molecular weight polyethylene film scraps (UHMWPE) (weight average molecular weight: 500,000)
(A-4) Crosslinked polyethylene film scraps (crosslinked PE) (gel fraction: 25%)

<Additives and other components>
(B-1) High density polyethylene (HDPE) (virgin resin, "Suntech B161" manufactured by Asahi Kasei Corporation)
(B-2) Polypropylene (PP) (virgin resin, "SunAllomer PB270A" manufactured by SunAllomer Co., Ltd.)
(C-1) Antioxidant (manufactured by BASF "Irganox 1010")
(C-2) Lubricant ("ALFLOW H-50F" manufactured by NOF Corporation)
(D-1) Calcium carbonate (“KK3000” manufactured by Yabashi Industry Co., Ltd.)

[Production of pulverized body]
Raw materials containing resin film/sheet offcuts and additives in the proportions shown in Table 1 were processed into pulverized bodies at processing temperatures shown in Table 1 using any of the methods shown below.

(Processing method a (semi-melting))
Resin film/sheet offcuts (if additives are included, resin film/sheet offcuts and additives are premixed for 5 minutes using a tumbler blender) are passed through an automatic granulator (Toyo Co., Ltd.). The resin was placed in a "Hypeletter HP-90" manufactured by Seiki Co., Ltd.), and the resin was semi-molten by heat generated by shearing the resin due to the rotation of the screw, and then processed into pellets with a built-in cutter. No external heat source heating was applied in the granulator.

(Processing method b (crimping))
Resin film/sheet offcuts are introduced into an inflation edge trim processing device ("REPRE H981-A" manufactured by HF), 4 to 10 offcuts are superimposed and crimped with a roll, and the built-in cutter cuts 5 mm. It was cut into squares and processed into pellets. No external heat source was applied during crimping.

(Processing method c-1 (melt kneading))
After pulverizing resin film/sheet offcuts into approximately 5 mm squares with a pulverizer, additives are added as necessary, premixed for 5 minutes using a tumbler blender, and fed to a feeder equipped with a push screw agitator. It was put into a twin-screw extruder (“TEM26SS” manufactured by Shibaura Machine Co., Ltd., L/D=48) and melt-kneaded. The maximum cylinder setting temperature was set to the processing temperature shown in Table 1. The resulting melt-kneaded product was extruded into a strand, cooled with water, cut with a strand cutter, and processed into pellets.
(Processing method c-2 (melt kneading))
Resin film/sheet offcuts (if additives are included, resin Film/sheet offcuts and additives were premixed using a tumbler blender for 5 minutes) was introduced and melt-kneaded. The maximum cylinder setting temperature was set to the processing temperature shown in Table 1. Granulation was performed by hot cutting with a built-in cutter.

(Processing method d (crushing))
The resin film/sheet offcuts were pulverized into pieces of about 5 mm square by a pulverizer.

The measurement and evaluation methods used in Examples and Comparative Examples are as follows.

[Measurement of maximum length of pulverized body]
For 50 pulverized bodies, the maximum length among the distances between two points on the surface of the pulverized bodies was measured with a vernier caliper, and the average value was determined to be the maximum length (mm).

[Measurement of Bulk Density of Pulverized Body]
The bulk density (g/cm ³ ) of the pulverized body was measured according to JIS K 7365.

[Smoke Emission During Production of Cleaning Agent]
Regarding the appearance of smoke in a series of cleaning agent manufacturing processes, a digital camera (Canon stock A photograph of the final stage portion of the processing equipment was taken using a company's "IXY650") and judged according to the following criteria.
・Evaluation criteria ◎ (excellent): No smoke is observed, and there is no hindrance to work ○ (good): Smoke is observed, but visibility is good up to 5 m ahead (photo taken above for all processing equipment (The final stage can be confirmed in the above photo), so it does not interfere with the work. × (Poor): Smoke is so intense that 5m ahead cannot be clearly seen (the final stage can be confirmed in the above photo. The work environment has deteriorated significantly because there is processing equipment that was not

[Coloring of detergent pellets]
A plate of detergent (dimensions: 90 mm × 50 mm × 2.5 mm) was molded using a screw injection molding machine (“EC100S” manufactured by Shibaura Kikai Co., Ltd.) (cylinder temperature: 220°C ± 10°C, mold temperature: : 60°C ± 5°C). A YI value was measured for one plate using a color difference meter.
・Evaluation criteria [in the case of a cleaning agent whose main component (more than 50% by mass) is PE]
◎ (excellent): compared to a similarly molded virgin PE plate, the increase in YI value is less than 30% ○ (good): compared to a similarly molded virgin PE plate, the YI value 30 to 100% increase
× (defective): YI value increased by more than 100% compared to a similarly molded virgin PE plate [in the case of a cleaning agent whose main component (more than 50% by mass) is PP]
◎ (excellent): compared to a similarly molded virgin PP plate, the increase in YI value is less than 30% ○ (good): compared to a similarly molded virgin PP plate, the YI value 30 to 100% increase
× (defective): YI value increased by more than 100% compared to similarly molded virgin PP plate

[Black spots in detergent pellets]
A plate of detergent (dimensions: 90 mm × 50 mm × 2.5 mm) was molded using a screw injection molding machine (“EC100S” manufactured by Shibaura Kikai Co., Ltd.) (cylinder temperature: 220°C ± 10°C, mold temperature: : 60°C ± 5°C). The number of black spots with a diameter of 0.1 mm or more was confirmed on the front and back of the four plates.
Evaluation criteria ◎ (excellent): 10 or less black spots ○ (good): 11 to 20 black spots × (defective): 21 or more black spots

[Measurement of weight average molecular weight]
The weight-average molecular weight of the detergent was measured using ultra-high temperature GPC (manufactured by Senshu Scientific Co., Ltd.) using 1-chloronaphthalene as an eluent and polystyrene as a calibration curve standard at a column temperature of 210°C. An RI (differential refraction) detector was used as a detector.

[Washing evaluation of polyethylene resin]
A blue-colored low-density polyethylene is used as a colored masterbatch, and 10% by mass of the colored masterbatch and 90% by mass of high-density polyethylene (hereinafter referred to as "PE") are mixed, and a small extruder (manufactured by Brabender " 500 g of the resin mixture was put into a plasticorder"), and the screw was rotated to discharge the resin mixture from the T-die to adhere pseudo-dirt to the inside of the molding machine.
After that, the cleaning agent obtained in Examples or Comparative Examples was put into the molding machine, and cleaning was performed by rotating the screw under conditions of a cylinder temperature of 200°C and a die temperature of 200°C. At this time, the amount of the cleaning agent required to switch from the blue color of PE to the color of the cleaning agent was measured from the purge waste discharged from the die, and was taken as the detergency value (g).
[Evaluation criteria]
◎ (excellent): The amount of purged waste is 250 g or less, and the washability is excellent. Yes, difficult to clean

[Washing evaluation of polypropylene resin]
500 g of a black molding material of polypropylene (hereinafter referred to as "PP") as a preceding resin was charged from a hopper at a cylinder temperature of 230° C. into an injection molding machine manufactured by Shibaura Kikai Co., Ltd. with a mold clamping force of 100 tons. The rotation of the screw was continued until the purge of the resin was completed, and after the rotation was stopped, the same temperature was retained for 15 minutes. After that, the cleaning agent obtained in Examples or Comparative Examples was poured from the hopper to clean the inside. At this time, the amount of the cleaning agent required to switch from the black color of PP to the color of the cleaning agent was measured from the purge debris discharged from the nozzle, and was taken as the detergency value (g).
[Evaluation criteria]
◎ (excellent): The amount of purged waste is 500 g or less, and the washability is excellent. Yes, difficult to clean

<Examples 1, 3 to 5, 8, 9, 11, 12>
The pulverized body obtained by processing the raw material containing resin film/sheet scraps and optional additives by any of the processing methods a to d described above, and other components, are processed by any of the following methods. and obtained a detergent. Table 1 shows the mixing ratio (% by mass) of the pulverized product and other components.
・Processing by melt-kneading (described as “melt-kneading” in Table 1)
The pulverized product and other components were premixed for 5 minutes using a tumbler blender, and melt-kneaded using a twin-screw extruder (TEM26SX manufactured by Shibaura Kikai Co., Ltd.). The extrusion conditions were a cylinder set temperature of 240° C. and a feed rate of 15 kg/hour. The melt-kneaded product thus obtained was extruded into a strand, cooled with water, and then cut with a strand cutter to obtain a detergent pellet.
・Processing by dry blending (described as “blending” in Table 1)
The grounds and other ingredients were dry blended for 5 minutes using a tumbler blender.

<Examples 2, 6, 7, 10, 13, 14, Comparative Examples 1, 2>
A pulverized body obtained by processing a raw material containing resin film/sheet offcuts and an additive was directly used as a cleaning agent.

Table 1 shows the measurement and evaluation results.

From the evaluation results, there was a significant difference between the examples of the present invention and the comparative examples obtained by the conventional processing method in that the examples had higher quality, workability and cleaning effect.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to obtain a cleaning agent for resin processing machines that exhibits excellent quality and cleaning effect while improving workability when resin film/sheet scraps generated in the production process are used as raw materials for the cleaning agent. can.

Claims (8)

A weight average molecular weight of 50,000 or more,
A pulverized body obtained by performing processing selected from the group consisting of crimping, semi-melting, and melt-kneading on a raw material containing resin film/sheet scraps mainly composed of polyolefin resin or styrene resin. including
The processing is performed without heating or with heating within a temperature range of 280 ° C. or less in the case of crimping, and without heating or with heating within a temperature range of 280 ° C. or less in the case of semi-melting. In the case of melt kneading, it is performed by heating within the temperature range of 160 ° C. or higher and 280 ° C. or lower.
A detergent for resin processing machines characterized by: The cleaning agent for resin processing machines according to claim 1, wherein the pulverized product has a bulk density of 0.10 g/cm3 ^or more. The cleaning agent for resin processing machines according to claim 1 or 2, wherein the maximum length of said pulverized body is 2 to 10 mm. 3. The process according to claim 1 or 2, wherein the processing is melt-kneading, including melt-kneading the raw material containing the resin film/sheet scraps in an extruder, and the L/D of the extruder is 45 or less. Detergent for resin processing machines. 3. The cleaning agent for resin processing machines according to claim 1, further comprising other components and obtained by melt-kneading or dry-blending said pulverized product and said other components. 3. The cleaning for resin processing machines according to claim 1, wherein the raw material further contains at least one additive selected from the group consisting of antioxidants, lubricants, surfactants, plasticizers, and inorganic fillers. agent. A method for producing the cleaning agent for resin processing machines according to claim 1 or 2,
Obtaining a pulverized body by performing processing selected from the group consisting of crimping, semi-melting, and melt-kneading on raw materials including resin film and sheet scraps,
The processing is performed without heating or with heating within a temperature range of 280 ° C. or less in the case of crimping, and without heating or with heating within a temperature range of 280 ° C. or less in the case of semi-melting. In the case of melt kneading, it is performed by heating within the temperature range of 160 ° C. or higher and 280 ° C. or lower.
A manufacturing method characterized by: A cleaning method comprising using the cleaning agent for resin processing machines according to claim 1 or 2.