Cleaning agents for resin processing machinery

Abstract

This invention relates to a cleaning agent for resin processing machinery, characterized in that it is a cleaning agent used to remove processing residues containing the target resin (C) from resin processing machinery. It comprises a thermoplastic resin (A) and a nonionic additive (B) with a melting or softening point less than 150°C, as represented by the following formula (I), where R is a hydrophobic organic group, n is an integer greater than or equal to 1, and X is a polar group. The cleaning agent exhibits a melt flow rate (MFR) of less than 30 g / 10 minutes at 280°C and a load of 2.16 kg, and the difference (SP1-SP2) between the solubility parameter (SP1) of the thermoplastic resin (A) and the solubility parameter (SP2) of the target resin (C) is +1.6 to -1.6 (cal / cm³). 3 ) 1 / 2 The difference between the solubility parameter (SP3) and SP2 (SP3-SP2) of the nonionic additive (B) is +1.6 to -1.6 (cal / cm³). 3 ) 1 / 2 The difference (SP3-SP4) between the solubility parameters of SP3 and the hydrophobic organic group R is 0.7 (cal / cm³). 3 ) 1 / 2 That's all. Rn-X···(I).

Description

Technical Field

[0001] This invention relates to cleaning agents for resin processing machinery. Background Technology

[0002] Typically, resin processing machinery such as extruders and injection molding machines are used for coloring, mixing, and molding resins. When a molding operation is completed, resin, dyes / pigments, and other additives used in that operation, as well as byproducts generated from the resin (such as thermal decomposition products and carbides), remain inside the molding machine. If these residues are left unattended, they can become contaminated in subsequent operations, potentially causing defects in the appearance of the resulting product. This is especially true when molding transparent resins; even trace amounts of contaminants can reduce the transparency of the resulting product, potentially leading to poor appearance. Therefore, it is desirable to completely remove these residues from the molding machine. This is particularly problematic in molds with multiple cavities and complex hot runner structures, where resin-based contaminants tend to accumulate in the flow path, especially when molding multiple products simultaneously.

[0003] Previously, in order to remove the aforementioned residues from processing machinery, methods were employed such as manually disassembling and cleaning the machinery, or performing so-called replacement operations (or cleaning operations), which involved directly filling the processing machinery with the next molding material (hereinafter referred to as "subsequent material") without stopping the machinery, allowing the subsequent material to be discharged along with the residues, thereby cleaning the inside of the processing machinery. Other methods included adding cleaning agents to the processing machinery for cleaning.

[0004] Among these methods, the use of cleaning agents to remove residues from processing machinery has excellent cleaning power and has therefore been widely used in recent years. Cleaning agents contain various components, typically consisting mainly of resins, surfactants, and other additives, as well as inorganic abrasives.

[0005] For example, Patent Document 1 describes the use of a cleaning agent (masterbatch) containing a fatty amide compound as an active ingredient, in which the resin of the subsequent material is blended. Patent Document 2 describes a cleaning agent containing a styrene-acrylonitrile copolymer resin, an alkyl sulfonate, and an alkylene glycol fatty acid ester. Furthermore, Patent Document 3 proposes a cleaning resin composition made by blending sodium alkylbenzene sulfonate and hydrophobic compounds (higher fatty acid metal salts, waxes, liquid paraffin, synthetic waxes, etc.) into a thermoplastic resin, and Patent Document 4 proposes a cleaning resin composition made by blending a neutral salt of alkylbenzene sulfonic acid and an anti-sticking compound into polystyrene.

[0006] Existing technical documents

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 4954397

[0009] Patent Document 2: Japanese Patent No. 4376648

[0010] Patent Document 3: Japanese Patent Application Publication No. 62-195045

[0011] Patent Document 4: Japanese Patent Application Publication No. 2-206636 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] However, the cleaning agent in Patent Document 1 causes unevenness due to fatty amide compounds in the molding machine, leading to contamination near the feed hopper and poor feeding of the cleaning agent. Furthermore, when flowing through complex hot runners, the cleaning agent does not mix sufficiently with the resin of the subsequent materials, resulting in inadequate cleaning.

[0014] In the cleaning agents described in Patent Documents 2-4, the ionic surfactants may cause stickiness due to moisture absorption, or the excessive lubricant effect may cause slippage on the dirt surface, resulting in reduced cleaning performance and insufficient cleaning effect.

[0015] Even with the use of cleaning agents as described above, it is still very difficult to effectively clean the complex hot runners. Depending on the situation, measures such as disassembling the mold may be necessary.

[0016] Therefore, the object of the present invention is to provide a cleaning agent for resin processing machinery that can effectively clean the barrel and complex hot runners during molding.

[0017] Methods for solving problems

[0018] In order to solve the above problems, the inventors conducted in-depth research, focusing on solubility parameters and melt flow rate (MFR), and found that a cleaning agent for resin processing machinery that takes into account the flowability and compatibility of resin components and additive components can solve the above problems, thus completing the present invention.

[0019] That is, the present invention is as follows. [1]

[0021] A cleaning agent for resin processing machinery, characterized in that,

[0022] It is a cleaning agent used to remove processing residues containing the resin (C) being cleaned from resin processing machinery.

[0023] The cleaning agent contains a thermoplastic resin (A) and a nonionic additive (B) with a melting or softening point of less than 150°C, as indicated by formula (I).

[0024] Rn-X···(I)

[0025] (In formula (I), R is a hydrophobic organic group, n is an integer greater than or equal to 1, and X is a polar group.)

[0026] The melt flow rate (MFR) of this cleaning agent is less than 30 g / 10 minutes under conditions of 280°C and a load of 2.16 kg.

[0027] The difference (SP1 - SP2) between the solubility parameter (SP1) of the aforementioned thermoplastic resin (A) and the solubility parameter (SP2) of the aforementioned target resin (C) is +1.6 to -1.6 (cal / cm³). 3 ) 1 / 2 ,

[0028] The difference between the solubility parameter (SP3) of the aforementioned nonionic additive (B) and that of SP2 (SP3-SP2) is +1.6 to -1.6 (cal / cm³). 3 ) 1 / 2 ,

[0029] The difference (SP3-SP4) between the solubility parameter (SP3) of SP3 and the hydrophobic organic group R is 0.7 (cal / cm³). 3 ) 1 / 2 above. [2]

[0031] The cleaning agent for resin processing machinery as described in [1], wherein the thermoplastic resin (A) comprises at least one selected from the group consisting of styrene-based resins and polyester-based resins. [3]

[0033] The cleaning agent for resin processing machinery as described in [1] or [2], wherein the thermoplastic resin (A) comprises a styrene-based resin or a polyester-based resin, and the content of the styrene-based resin or the polyester-based resin in the cleaning agent for resin processing machinery is 40% by mass or more. [4]

[0035] The cleaning agent for resin processing machinery as described in any one of [1] to [3], wherein the nonionic additive (B) comprises a lubricant or a surfactant, and the content of the lubricant or surfactant in the cleaning agent for resin processing machinery is 10% by mass or less. [5]

[0037] The cleaning agent for resin processing machinery as described in any one of [1] to [4], wherein SP1 and SP3 have a concentration of 9 to 11 cal / cm³. 3 ) 1 / 2 . [6]

[0039] The cleaning agent for resin processing machinery as described in any one of [1] to [5], wherein the resin (C) to be cleaned is a styrene-based resin and / or a polyester-based resin. [7]

[0041] A cleaning method for a resin processing machine, characterized in that it uses a cleaning agent for resin processing machines as described in any one of [1] to [6]. [8]

[0043] The use of the cleaning agent for resin processing machinery as described in any one of [1] to [6] in the cleaning of resin processing machinery.

[0044] The effects of the invention

[0045] According to the present invention, a cleaning agent for resin processing machinery can be provided that can effectively clean the barrel and complex hot runners during molding. Detailed Implementation

[0046] The embodiments of the present invention (hereinafter referred to as "this embodiment") will be described in detail below. It should be noted that the following embodiments are illustrative of the present invention and are not intended to limit the present invention to these embodiments only. Furthermore, the present invention can be modified in various ways without departing from its essential points.

[0047] Cleaning agents for resin processing machinery

[0048] The cleaning agent for resin processing machinery of this embodiment (hereinafter also referred to as "cleaning agent") is a cleaning agent used to remove processing residues containing the resin (C) to be cleaned from resin processing machinery. It comprises a thermoplastic resin (A) and a nonionic additive (B) with a melting point or softening point of less than 150°C as represented by the following formula (I).

[0049] Rn-X···(I)

[0050] (In formula (I), R is a hydrophobic organic group, n is an integer greater than or equal to 1, and X is a polar group.)

[0051] Under conditions of 280°C and a load of 2.16 kg, the melt flow rate (MFR) is less than 30 g / 10 min, and the difference (SP1 - SP2) between the solubility parameter (SP1) of the above-mentioned thermoplastic resin (A) and the solubility parameter (SP2) of the above-mentioned target resin (C) is +1.6 to -1.6 (cal / cm³). 3 ) 1 / 2 The difference between the solubility parameter (SP3) of the aforementioned nonionic additive (B) and that of SP2 (SP3-SP2) is +1.6 to -1.6 (cal / cm³). 3 ) 1 / 2 The difference (SP3-SP4) between the solubility parameter (SP3) of SP3 and the hydrophobic organic group R is 0.7 (cal / cm³). 3 ) 1 / 2 above.

[0052] The cleaning agent for resin processing machinery of this embodiment can be used at the end of a molding operation of thermoplastic resin using processing machinery to remove processing residues containing the resin used in the operation (the resin to be cleaned (C)), additives such as dyes / pigments, and deteriorated products generated from the resin. In particular, in molding machines with multi-cavity hot runners that can be assembled into multiple parts, it can clean not only the inside of the barrel and the screw, but also the inside of the complex hot runners during the molding operation.

[0053] The inventors focused on the relationship between the polarity of the resin used in molding, a major cause of fouling in resin processing machinery, and the polarity of the resin and additives constituting the cleaning agent. They discovered that a solubility parameter, obtained through Fedoros's extrapolation method, serves as an indicator of this polarity. Specifically, they found that the solubility parameter can be used to limit the likelihood of fouling removal when the resin used in molding and the resin constituting the cleaning agent are more similar (higher compatibility). Furthermore, they discovered that the additives included in the cleaning agent are also important for promoting resin compatibility and need to be limited using the solubility parameter.

[0054] It should be noted that in this disclosure, the solubility parameters (SP values) of the thermoplastic resin (A), the nonionic additive (B), and the resin to be cleaned (C) are calculated using the following formula based on Fedors's extrapolation method (RF Fedors, Polym. Eng. Sci., 14(2), 147-154 (1974), hereinafter referred to as "Fedors's paper").

[0055] Fedors formula: SP value [(cal / cm²)] 3 ) 1 / 2 ]=(E v / v) 1 / 2 =(ΣΔei / ΣΔv i ) 1 / 2

[0056] E v Evaporation energy [cal / mol]

[0057] v: Molar volume [cm] 3 / mol]

[0058] Δe i Evaporation energy of atoms or groups of atoms in each component [cal / mol]

[0059] Δv i Molar volume of each atom or group of atoms [cm] 3 / mol]

[0060] Here, the evaporation energy and molar volume used in the above formula are values ​​at 25°C in the aforementioned Fedors paper. The aforementioned Fedors paper states that the SP value of the resin is temperature-dependent, and the following relationship exists between the temperature at which the resin is used and the volume expansion rate α of the resin.

[0061] SP value at the temperature used [(cal / cm²)] 3 ) 1 / 2 SP value at 25℃ [(cal / cm²)] 3 ) 1 / 2 ]×[1+1.13×α×(T1-T2)]

[0062] α: Volume expansion rate (volume expansion coefficient) [1 / K]

[0063] T1: 298K (25℃)

[0064] T2: Actual operating temperature [K]

[0065] In this disclosure, the SP values ​​(SP1 and SP2) of the thermoplastic resin (A) and the resin to be cleaned (C) are values ​​calculated at the temperature at which they are used, and the SP value (SP3) of the nonionic additive (B) is a value calculated at 25°C.

[0066] For the reasons described above, the thermoplastic resin (A) and nonionic additive (B) in this embodiment are selected based on the type of resin (C) that is the target of cleaning processing residues (dirt) in the resin processing machinery. Furthermore, since the SP value can be calculated based on Fedors' algorithm, the combination of thermoplastic resin (A) and nonionic additive (B) can be determined based on the pre-calculated SP value.

[0067] The components of the cleaning agent for resin processing machinery according to this embodiment will be described in detail below.

[0068] <Thermoplastic Resin (A)>

[0069] The thermoplastic resin (A) contained in the cleaning agent for resin processing machinery in this embodiment is not particularly limited as long as the SP value (SP1) meets the specific conditions described later. Examples include styrene-based resins, polyester-based resins, polyolefin-based resins, polyamide-based resins, cellulose-based resins, polycarbonate, polymethyl methacrylate, etc.

[0070] The thermoplastic resin (A) can be a single type or a combination of two or more types.

[0071] The difference (SP1 - SP2) between the SP value (SP1) of thermoplastic resin (A) and the SP value (SP2) of the resin being cleaned (C) is +1.6 to -1.6 (cal / cm³). 3 ) 1 / 2 The preferred value is +1.2 to -1.2 (cal / cm³). 3 ) 1 / 2 More preferably, it is +1.0 to -1.0 (cal / cm³). 3 ) 1 / 2 When SP1-SP2 is within this range, the thermoplastic resin (A) and the resin (C) being cleaned have good compatibility and can achieve excellent cleaning results.

[0072] Furthermore, regarding the SP value (SP1) of the thermoplastic resin (A), there are no particular limitations as long as SP1-SP2 meet the above-mentioned range, and it is preferably 9-11 (cal / cm³), which is close to the solubility parameter of common engineering plastics. 3 ) 1 / 2 .

[0073] For example, when cleaning the multi-cavity hot runner of a preform for bottle ejection, since the resin (C) to be cleaned is mostly polyethylene terephthalate, the thermoplastic resin (A) is preferably polyethylene terephthalate, polybutylene terephthalate, styrene-based resin, and polycarbonate, especially those with SP values ​​close to those of polyethylene terephthalate.

[0074] Examples of styrene-based resins include polystyrene, or a copolymer of styrene with one or more other monomers, wherein the styrene content is 50% by mass or more. Examples of other monomers in the copolymer with styrene include acrylonitrile, butadiene, isoprene, methyl acrylate, and methyl methacrylate. Specific examples of styrene-based resins include polystyrene, styrene-acrylonitrile copolymers, styrene-butadiene-acrylonitrile copolymers, styrene-isoprene copolymers, and styrene-methyl methacrylate copolymers. Among these, styrene-acrylonitrile copolymers and styrene-butadiene-acrylonitrile copolymers are preferred.

[0075] The SP values ​​of representative thermoplastic resins are as follows (unit: cal / cm). 3 ) 1 / 2 As mentioned above, the SP value varies depending on the operating temperature. The values ​​described here are based on the above calculation formula, assuming an operating temperature of 280°C. Polystyrene: 9.3, Styrene-acrylonitrile copolymer (styrene:acrylonitrile ratio of 70:30): 9.9, Styrene-butadiene-acrylonitrile copolymer (styrene:butadiene:acrylonitrile ratio of 45:30:25): 9.8, Polycarbonate: 9.9, Polyethylene: 8.1, Polyamide (66): 11.1, Polyethylene terephthalate: 10.8, Polybutylene terephthalate: 10.6.

[0076] Assuming the cleaning agent for resin processing machinery is 100% by mass, the content of thermoplastic resin (A) is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more. When the content of thermoplastic resin (A) is within the above range, the resin component of the cleaning agent remaining in the machinery is easily replaced by the resin of subsequent materials.

[0077] In particular, when the thermoplastic resin (A) includes styrene-based resin or polyester-based resin, assuming the cleaning agent for resin processing machinery is 100% by mass, the content of styrene-based resin or polyester-based resin is preferably 20% by mass or more, more preferably 40% by mass or more, and even more preferably 60% by mass or more, respectively. When the content of styrene-based resin or polyester-based resin is within the above range, it is easier to achieve a cleaning effect on dirt adhering to the metal surface.

[0078] <Nonionic Additive (B)>

[0079] The nonionic additive (B) (hereinafter also referred to as "additive (B)") contained in the cleaning agent for resin processing machinery in this embodiment is not particularly limited as long as it has the structure shown in the following formula (I), a melting point or softening point of less than 150°C, and an SP value (SP3) that meets the specific conditions described later.

[0080] Rn-X···(I)

[0081] (In formula (I), R is a hydrophobic organic group, n is an integer greater than or equal to 1, and X is a polar group.)

[0082] Nonionic additive (B) can be a single type or a combination of two or more types.

[0083] The inventors have discovered that the nonionic additive (B) is also important for promoting the compatibility between the thermoplastic resin (A) and the resin (C) being cleaned, and this needs to be limited by solubility parameters. Furthermore, by including the nonionic additive (B), the residue of the cleaning agent itself in the processing machinery can be suppressed, resulting in superior cleaning performance compared to conventional methods. The cleaning agent can also flow effectively within complex hot runners, thus effectively removing accumulated processing residues (dirt). In this way, due to the good flow of the cleaning agent within the hot runners and the minimal residue, a cleaning method that can be performed simultaneously with molding can be achieved, further improving the efficiency of the cleaning operation.

[0084] The difference between the SP value (SP3) of the nonionic additive (B) and the SP value (SP2) of the resin being cleaned (C) (SP3-SP2) is +1.6 to -1.6 (cal / cm³). 3 ) 1 / 2 The preferred value is +1.2 to -1.2 (cal / cm³). 3 ) 1 / 2 More preferably, it is +1.0 to -1.0 (cal / cm³). 3 ) 1 / 2 When SP3-SP2 is within this range, the additive (B) effectively penetrates into the resin (C) being cleaned, which contains processing residues (dirt) from the resin processing machinery, causing it to float. However, when SP3-SP2 is outside this range, the compatibility between the thermoplastic resin (A) and the additive (B) deteriorates, and the additive (B) does not mix evenly with the thermoplastic resin (A), tending to result in uneven cleaning effects.

[0085] Furthermore, the difference between the SP value (SP3) of the nonionic additive (B) and the SP value (SP4) of the hydrophobic organic group R of the nonionic additive (B) (SP3-SP4) is 0.7 (cal / cm). 3 ) 1 / 2 The larger the SP3-SP4 value, the greater the polarity difference between the hydrophobic organic group R and the polar group X. This enhances the hydrophobic effect of the hydrophobic organic group R and increases the hydrophobicity of the cleaning agent surface. Therefore, it can inhibit metal adhesion of the cleaning agent, increase the discharge characteristics of the cleaning agent, and improve non-residue properties. If SP3-SP4 is less than 0.7 (cal / cm³),... 3 )1 / 2 If not, the non-residue property cannot be fully utilized. That is, by controlling the values ​​of SP3 and SP4, additive (B) can be uniformly introduced into thermoplastic resin (A), while achieving a balance between the compatibility of thermoplastic resin (A) and additive (B), the floating effect of processing residues (dirt) of additive (B), and the inhibition of metal adhesion.

[0086] Furthermore, regarding the SP value (SP3) of the nonionic additive (B), there are no particular limitations as long as SP3-SP2 and SP3-SP4 meet the above-mentioned ranges. Preferably, it is 9-11 (cal / cm³), which is similar to the solubility parameter of common engineering plastics. 3 ) 1 / 2 .

[0087] Examples of hydrophobic organic groups R include long-chain alkyl groups such as stearyl group and isostearyl group, amide group, long-chain fluorocarbon group, alkylphenyl group, 12-hydroxystearyl group, etc.

[0088] Examples of polar groups X include carboxyl, hydroxyl, thiol, ester, thioester, carbonyl, amino, amide, formyl, acetal, cyano, ether, and alkoxy groups.

[0089] When the polar group X is a carboxyl group, hydroxyl group, ester group, etc., common fatty acids, fatty acid esters, fatty acid amides and other lubricants and surfactants can be cited as candidates as additives (B).

[0090] Hydrophobic organic group R and polar group X can have an oligomer or polymer structure together as part of the structure. In this case, the SP value (SP4) of only hydrophobic organic group R can also be calculated.

[0091] The nonionic additive (B) has a melting point or softening point of less than 150°C. If the melting point or softening point is above 150°C, the additive (B) may not be uniformly mixed during melt compounding with the thermoplastic resin (A), or it may remain in the hot runner during cleaning. The melting point or softening point of the additive (B) is preferably 30–140°C, more preferably 60–130°C. Furthermore, if it is uniformly mixed in the resin during compounding, it is not a problem even if it is a liquid at room temperature.

[0092] It should be noted that ionic additives (surfactants, lubricants, etc.) have high melting points and can become sticky due to moisture absorption or slip on dirt surfaces due to excessive lubrication, which can easily reduce cleaning effectiveness. From the above perspectives, ionic additives (surfactants, lubricants, etc.) are not ideal as additives in cleaning agents.

[0093] The content of the nonionic additive (B) is not particularly limited. Assuming the cleaning agent for resin processing machinery is 100% by mass, the content of the nonionic additive (B) is preferably 0.1% by mass or more and less than 15% by mass, more preferably 0.2% to 10% by mass, and even more preferably 0.5% to 5% by mass. When the content of additive (B) is 10% by mass or more, the additive (B) may remain in the resin processing machinery or hot runner, the additive (B) itself may easily deteriorate, or there may be a tendency for poor feeding of the cleaning agent when it is added due to the strong external slipping effect of the cleaning agent itself.

[0094] Representative nonionic additives and their SP values ​​are as follows (unit: cal / cm³). 3 ) 1 / 2 The recorded values ​​are SP3 (SP4). Glyceryl stearate: 10.2 (8.3), stearamide: 9.8 (8.3), ethylene bis-stearamide: 9.6 (8.3), stearyl alcohol: 9.5 (8.3), stearic acid: 9.1 (8.3), isostearyl alcohol: 8.8 (7.7).

[0095] <Other Ingredients>

[0096] The cleaning agent for resin processing machinery of this embodiment may contain various other components depending on its cleaning purpose and the performance required for its application. Examples of such other components include common inorganic fillers, polyethylene glycol, and antioxidants.

[0097] To reduce the possibility of not being completely discharged if the cleaning agent for resin processing machinery remains in the hot runner with complex flow paths, the content of other components is preferably less than 10% by mass, more preferably less than 5% by mass, and even more preferably less than 1% by mass.

[0098] <Manufacturing Method of Cleaning Agent for Resin Processing Machinery>

[0099] The manufacturing method of the cleaning agent for resin processing machinery in this embodiment is not particularly limited. As a preferred method, a method comprising the following steps can be cited: a resin composition containing the above-mentioned thermoplastic resin (A), nonionic additive (B), and other components to be mixed as needed is melt-mixed using a melt-mixing apparatus such as a kneader, extruder, or Banbury mixer; the resulting melt-mixed material is extruded into a filament and then shaped into granules. As the melt-mixing apparatus used here, an extruder is preferred from the viewpoint of being able to fully mix the thermoplastic resin (A) and the additive (B), and a twin-screw extruder is more preferred. By using a twin-screw extruder in this way, the additive (B) is easily and uniformly dispersed in the thermoplastic resin (A), thus the extrudability is stable, and there is a tendency to suppress pulsation and the like in the filament discharged from the extruder.

[0100] If the mixing is insufficient, or if the additive (B) is dry-mixed and the thermoplastic resin (A) is not evenly dispersed or is only spread out, segregation or seepage may occur in the barrel or hot runner, the additive (B) may adhere to the feed hopper, unevenness may occur during molding and cleaning, and overfilling may occur. Not only will the cleaning performance not be fully obtained, but it may also lead to contamination or damage to the mold, including the hot runner.

[0101] When mixing and melt-blending various components, commonly used equipment can be used, such as drum mixers, ribbon mixers, premixing devices like Super Mixers, gravimetric feeders, single-screw extruders, twin-screw extruders, and worm gear kneaders. Furthermore, during melt-blending, it is preferable to perform open degassing by removing degassed components from the open vent (exhaust port) under normal pressure, and depressurized degassing by removing degassed components from the open vent (exhaust port) as needed.

[0102] It should be noted that the barrel temperature during melt mixing using an extruder is preferably set to below 320°C, and more preferably below 300°C. The residence time of the molten resin within the extruder should be as short as possible; therefore, the barrel temperature is set with the above considerations in mind.

[0103] The cleaning agent for resin processing machinery of this embodiment has a melt flow rate (MFR) of 30 g / 10 min or less, preferably 1 to 25 g / 10 min, and more preferably 3 to 20 g / 10 min, under conditions of 280°C and a load of 2.16 kg (according to ISO 1133). If the MFR is greater than 30 g / 10 min, the cleaning agent flows too much, and therefore, during cleaning performed simultaneously with molding, excessive flow of cleaning agent into the mold may cause overfilling, potentially leading to mechanical breakage. In addition, if the melt mixing is too strong, the thermoplastic resin (A) and additive (B) may deteriorate, which may also increase the MFR, thus potentially reducing the cleaning effect. When the MFR is less than 1 g / 10 min, there is a possibility of insufficient filling during cleaning performed simultaneously with molding, or a tendency for residues to easily form in the hot runner.

[0104] <Processing Residues>

[0105] The processing residues inside the resin processing machinery that can be cleaned using the cleaning agent for resin processing machinery of this embodiment include the resin to be cleaned (C) (the resin used in the processing operation), and may also include additives such as dyes / pigments, deterioration products generated from the resin to be cleaned (C) (e.g., thermal decomposition products, carbides, etc.).

[0106] <Resin (C) to be cleaned>

[0107] Regarding the resin (C) to be cleaned, there are no particular limitations as long as its SP value (SP2) meets the specific conditions mentioned above. Examples include common general-purpose resins such as styrene-based resins, polyester-based resins, polyolefin-based resins, polyamide-based resins, cellulose-based resins, polycarbonate, and polymethyl methacrylate, as well as thermoplastic resins such as engineering plastics and super engineering plastics.

[0108] Cleaning Method for Resin Processing Machinery Using Resin Processing Machinery Cleaning Agents

[0109] The resin processing machinery that can use the cleaning agent for resin processing machinery of this embodiment is not particularly limited as long as it is a resin processing machinery that processes thermoplastic resin, such as an injection molding machine or an extruder. The cleaning agent of this embodiment is characterized by its high cleaning effect even in cleaning hot runners with complex shapes.

[0110] Cleaning of the hot runner can be performed as follows: Heating the interior to the resin melting temperature is done under the same molding conditions as usual. The cleaning agent is then passed through the runner under the same molding conditions as the resin (C) being cleaned. The product is then removed as a molded part. It should be noted that if insufficient material is suspected during molding operations using the cleaning agent, the hot runner temperature can be increased by approximately 10–30°C.

[0111] If only the hot runner and cavity are cleaned, the cleaning agent can be circulated while the mold is open, thereby recovering the molten cleaning agent directly from the gate.

[0112] Furthermore, even when there is a slight residue of processing material (the resin being cleaned (C)) inside, even if it is not necessary to completely remove the dirt, the cleaning agent of this embodiment will slowly penetrate into the processing residue, thus achieving a sufficient cleaning effect.

[0113] Example

[0114] The present invention will be described in more detail below through examples and comparative examples. The present invention is not limited to the following examples, provided that its essential points are not departed from.

[0115] The components used in the examples and comparative examples are described below.

[0116] <Thermoplastic Resin (A)>

[0117] (A-1)PET (Polyethylene terephthalate)

[0118] (A-2)AS (Styrene-Acrylonitrile Copolymer) (Styrene:Acrylonitrile ratio is 70:30)

[0119] (A-3) PC (Polycarbonate)

[0120] (A-4) ABS (Styrene-Butadiene-Acrylonitrile Copolymer) (Styrene:Butadiene:Acrylonitrile ratio is 45:30:25)

[0121] (A-5), (A-6) PS (Polystyrene)

[0122] (A-7)LDPE (Low-density polyethylene)

[0123] The solubility parameters SP1 of (A-1) to (A-7) obtained by Fedors' extrapolation method, and the melt flow rate (MFR) (g / 10 min) measured at 280°C and with a load of 2.16 kg (according to ISO 1133) are shown in Table 1.

[0124] [Table 1]

[0125]

[0126] <Nonionic Additive (B)>

[0127] (B-1) Glyceryl stearate

[0128] (B-2) stearamide

[0129] (B-3) Ethylene bis-stearamide

[0130] (B-4) Stearyl alcohol

[0131] (B-5) Stearic acid

[0132] (B-6) Isostearol

[0133] <Other Nonionic Additives>

[0134] (B-7) Polyethylene glycol (molecular weight 10,000)

[0135] (B-8) Sodium dodecyl sulfate

[0136] The melting or softening points of (B-1) to (B-8), the solubility parameters SP3 of (B-1) to (B-8) obtained by Fedors' algorithm, and the solubility parameters SP4 of the hydrophobic organic groups R of (B-1) to (B-8) are shown in Table 2.

[0137] [Table 2]

[0138]

[0139] <Resin (C) to be cleaned>

[0140] (C-1)PA66 (Polyamide 66)

[0141] (C-2)PET (Polyethylene terephthalate)

[0142] (C-3)PBT (Polybutylene terephthalate)

[0143] (C-4) ABS (Styrene-Butadiene-Acrylonitrile Copolymer) (Styrene:Butadiene:Acrylonitrile ratio is 45:30:25)

[0144] (C-5)PC (Polycarbonate)

[0145] (C-6)PE (Polyethylene)

[0146] The solubility parameters SP2 of (C-1) to (C-6) obtained by Fedors' algorithm are shown in Table 3.

[0147] [Table 3]

[0148]

[0149] The methods for determining / evaluating the cleaning agents obtained in the examples and comparative examples are as follows.

[0150] [Performance Evaluation]

[0151] (Extrudability)

[0152] When preparing the resin compositions of the examples and comparative examples, the shape and granulation state of the filament from the extruder were observed and evaluated using the following evaluation criteria.

[0153] [Evaluation Criteria]

[0154] 〇 (Good): The wire is formed stably, so the particle size is uniform.

[0155] × (Defect): The wire material did not form stably, resulting in uneven particle size.

[0156] The instability of the wire material is believed to be due to the deterioration or segregation of additive (B), which can lead to fluctuations in quality and uneven performance, and is therefore generally not preferred.

[0157] (MFR)

[0158] Regarding the granules of the cleaning agents obtained in the examples and comparative examples, the melt flow rate (MFR) (g / 10 min) was determined according to ISO 1133 at 280°C and a load of 2.16 kg.

[0159] (Cleanability)

[0160] The cleaning properties of the cleaning agents obtained in the examples and comparative examples were evaluated using an injection molding machine with a multi-cavity hot runner system having 96 preform combinations. The mold closing time was set to 350t, and the cycle time for one injection was 20 seconds.

[0161] Regarding the cleaning target resin (C) used as a dirt material, in order to clearly switch cleaning methods, 5% by mass of phthalocyanine blue coloring masterbatch is mixed with 100% by mass of the cleaning target resin (C) and used to color it blue.

[0162] To ensure full adhesion to the inner wall of the injection molding machine, the colored cleaning resin (C) is allowed to flow thoroughly through the barrel until the discharged resin is completely replaced with blue. This process is then repeated in the same manner as the molding operation, ensuring that the hot runner and cavity are also filled with the colored cleaning resin (C).

[0163] The cleaning agent obtained in the examples and comparative examples was then used to clean the inside of the barrel. At this time, in order to confirm the cleaning performance inside the barrel, the nozzle tip on the barrel side was separated from the mold, and only the colored resin (C) (dirt) inside the barrel was discharged for visual inspection.

[0164] Next, after the barrel cleaning is completed, the nozzle is brought into contact with the mold, and the cleaning agent is allowed to flow into the hot runner under the same conditions as normal molding, so that cleaning is carried out while molding.

[0165] Since the amount of cleaning agent varies depending on the type of resin (C) being cleaned, the amount of natural product required when distributing uncolored resin (C) (natural product) will be used as a standard, and the evaluation will be conducted by comparing it with that amount.

[0166] [Evaluation Criteria]

[0167] ◎(Excellent): The colored resin (C) being cleaned is completely removed, and compared to the case of commercial natural products, it can be cleaned with less than 1 / 3 of the amount.

[0168] 〇 (Good): The colored resin (C) being cleaned is completely removed, and compared to the case of circulating natural products, it is possible to clean in an amount greater than 1 / 3 and less than 1 / 2.

[0169] △(Qualified): The colored resin (C) being cleaned is completely discharged, and compared with the case of circulating natural products, it can be cleaned in a quantity greater than 1 / 2 and less than 1 / 1.

[0170] × (Defective): Compared to the case of commercially available natural products, even when cleaning with a quantity greater than 1 / 1, the colored resin (C) being cleaned was not completely removed and remained.

[0171] (Non-residual)

[0172] The non-residual properties of the cleaning agent itself in the barrel and hot runner were evaluated using an injection molding machine with a multi-cavity hot runner having 96 preform combinations. A cleaning operation was performed until the cleaning agent was discharged. Then, uncolored resin (C) (natural product) was circulated through the molding machine in the same order as the cleaning performance evaluation described above, first in the barrel, then in the hot runner, and the replacement of the cleaning agent was visually evaluated.

[0173] [Evaluation Criteria]

[0174] ◎(Excellent): No cleaning agent residue remains. When cleaning the target resin (C) (natural product), it can be replaced with natural product within 10 injections.

[0175] 〇 (Good): The cleaning agent leaves almost no residue. When cleaning the target resin (C) (natural product), it can be replaced with natural product within 11 to 20 injections.

[0176] △(Qualified): There is residue of cleaning agent, but when the resin (C) (natural product) to be cleaned is in circulation, it can be replaced with natural product within 21 to 40 injections.

[0177] × (Defective): There is residue of cleaning agent, which makes it difficult to replace even the resin (C) (natural product) being cleaned, or requires more than 41 injections.

[0178] (Examples 1-12, Comparative Examples 1-6)

[0179] The resin composition containing each component in the proportions (mass%) shown in Table 4 was premixed for 5 minutes using a drum mixer and then melt-blended directly using a twin-screw extruder (Shibaura Machine Manufacturing, TEM58SS). The extrusion conditions were set at a barrel temperature of 280°C (Comparative Example 5, using A-7 resin alone, was only 200°C) and a feed rate of 10 kg / hour. The resulting melt blend was extruded into filaments, water-cooled, and then cut into granules using a filament pelletizer to obtain granular cleaning agent.

[0180] (Comparative Example 7)

[0181] Using a drum mixer, mix and disperse B-2 and B-3 in A-2 at the mixing ratios shown in Table 4 for 5 minutes, and use the mixture directly as a cleaning agent.

[0182] The obtained cleaning agent was measured and evaluated, and the results are shown in Table 4.

[0183]

[0184] The evaluation results show that the cleaning agent containing thermoplastic resin (A) and nonionic additive (B) with solubility parameters similar to the resin (C) being cleaned exhibits superior cleaning performance and residue-free properties. Furthermore, by controlling the solubility parameters of thermoplastic resin (A) and nonionic additive (B), the nonionic additive (B) can be uniformly dispersed during extrusion, preventing a decrease in cleaning performance caused by extreme exudation or viscosity reduction.

[0185] Industrial applicability

[0186] According to the present invention, the combination of resin and additives constituting the cleaning agent for resin processing machinery can be easily designed according to the solubility parameters, and it can also effectively perform cleaning in very complex hot runners. The cleaning agent can be manufactured in such a customized form according to the type of resin to be cleaned.

Claims

1. A cleaning agent for resin processing machinery, characterized in that, It is a cleaning agent used to remove processing residues containing the resin (C) being cleaned from resin processing machinery. This cleaning agent contains a thermoplastic resin (A) and a nonionic additive (B) with a melting or softening point of less than 150°C, as indicated by formula (I), but does not contain ionic surfactants. In formula (I), R represents a hydrophobic organic group, n is an integer greater than or equal to 1, and X represents a polar group. Rn-X···(I) The melt flow rate (MFR) of this cleaning agent is less than 30 g / 10 minutes under conditions of 280°C and a load of 2.16 kg. The difference (SP1 - SP2) between the solubility parameter SP1 of the thermoplastic resin (A) and the solubility parameter SP2 of the resin (C) to be cleaned is +1.6 to -1.6 (cal / cm³). 3 ) 1 / 2 , The difference between the solubility parameters SP3 and SP2 of the nonionic additive (B) (SP3 - SP2) is +1.6 to -1.6 (cal / cm³). 3 ) 1 / 2 , The difference (SP3 - SP4) between the solubility parameter SP3 and the hydrophobic organic group R is 0.7 (cal / cm³). 3 ) 1 / 2 above, The solubility parameter, i.e., the SP value, is calculated using the following Fedors formula. Fedors formula: SP value [(cal / cm²)] 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 Evaporation energy of atoms or groups of atoms in each component [cal / mol] Δv i Molar volume of each atom or group of atoms [cm] 3 / mol] Here, the evaporation energy and molar volume used in the above formula are values ​​at 25°C; it should be noted that in the case of thermoplastic resin (A) and the resin to be cleaned (C), the SP value at the operating temperature is used, calculated by the following formula. SP value at the temperature used [(cal / cm²)] 3 ) 1 / 2 SP value at 25℃ [(cal / cm²)] 3 ) 1 / 2 ]×[1+1.13×α×(T1-T2)] α: Volume expansion rate (volume expansion coefficient) [1 / K] T1: 298K (25℃) T2: Temperature during actual use [K].

2. The cleaning agent for resin processing machinery as described in claim 1, wherein, The thermoplastic resin (A) comprises at least one selected from the group consisting of styrene-based resins and polyester-based resins.

3. The cleaning agent for resin processing machinery as described in claim 1 or 2, wherein, a... The cleaning agent for the resin processing machinery is 100% by mass, and the content of the thermoplastic resin (A) is 70% by mass or more.

4. The cleaning agent for resin processing machinery as described in claim 1 or 2, wherein, a... The cleaning agent for resin processing machinery is 100% by mass, and the content of the nonionic additive (B) is 0.2% to 10% by mass.

5. The cleaning agent for resin processing machinery as described in claim 1 or 2, wherein, The thermoplastic resin (A) comprises a styrene-based resin or a polyester-based resin, and the content of the styrene-based resin or the polyester-based resin in the cleaning agent for resin processing machinery is 40% by mass or more.

6. The cleaning agent for resin processing machinery as described in claim 1 or 2, wherein, The nonionic additive (B) contains a lubricant or a surfactant, and the content of the lubricant or the surfactant in the cleaning agent for resin processing machinery is less than 10% by mass.

7. The cleaning agent for resin processing machinery as described in claim 1 or 2, wherein, The SP1 and SP3 have a concentration of 9–11 (cal / cm³). 3 ) 1 / 2 .

8. The cleaning agent for resin processing machinery as described in claim 1 or 2, wherein, The resin (C) to be cleaned is a styrene-based resin and / or a polyester-based resin.

9. The cleaning agent for resin processing machinery as described in claim 1 or 2, wherein, The difference (SP1 - SP2) between the solubility parameter SP1 of the thermoplastic resin (A) and the solubility parameter SP2 of the resin (C) to be cleaned is +1.0 to -1.6 (cal / cm³). 3 ) 1 / 2 .

10. The cleaning agent for resin processing machinery as described in claim 1 or 2, wherein, The difference (SP3 - SP2) between the solubility parameter SP3 of the nonionic additive (B) and the solubility parameter SP2 of the resin being cleaned (C) is +1.0 to -1.6 (cal / cm³). 3 ) 1 / 2 .

11. The cleaning agent for resin processing machinery as described in claim 1 or 2, wherein, The melt flow rate (MFR) of this cleaning agent is 3 g / 10 min to 30 g / 10 min under conditions of 280°C and 2.16 kg load.

12. A cleaning method for a resin processing machine, characterized in that, It uses the cleaning agent for resin processing machinery as described in any one of claims 1 to 11.

13. The use of the cleaning agent for resin processing machinery according to any one of claims 1 to 11 in the cleaning of resin processing machinery.

Images