A processing aid for wood-plastic composite materials and its preparation method

Abstract

This invention relates to the field of materials processing technology, and discloses a processing aid for wood-plastic composites and its preparation method, to solve the problems of lubrication and extrusion in the processing of high wood flour content. The aforementioned processing aid, by weight, comprises 5-95 parts modified polysiloxane, 5-95 parts hydrocarbon wax, 5-95 parts fatty acid, 5-95 parts carboxylic acid ester, 5-95 parts fatty amide, 5-95 parts fatty alcohol, 5-95 parts metal soap, and 1-5 parts other additives. The processing aid of this application is applied to the processing and extrusion of wood-plastic composites, utilizing the complementary advantages of the lubrication effect of small molecule lubricants and the excellent properties of modified polysiloxane to prepare a composite lubricant. Simultaneously, the structural advantage of the polar groups in the polysiloxane has a coating effect on wood flour particles that have adsorbed other polar small molecules, while the long-chain alkyl portion achieves good compatibility with the polyolefin resin through entanglement, preventing the precipitation of other polar small molecules. The composite lubricant offers high cost-effectiveness and excellent processing lubrication and defect-free product extrusion appearance.

Description

Technical Field

[0001] This invention relates to the field of materials processing technology, and more specifically, to a processing aid for wood-plastic composite materials and its preparation method. Background Technology

[0002] With economic development and increasing environmental awareness, wood-plastic composite materials (WPCs) are gaining more and more attention and are widely used in transportation, home decoration, and construction industries. WPCs are mainly composed of polyolefin thermoplastic resins mixed with wood flour, lignocellulose, or lignin, and are produced through extrusion molding. Wood flour, lignocellulose, and lignin are renewable resources, and their combination with polyolefin resins can be processed using thermoplastic processing methods, thus reducing the use of fossil fuels and meeting low-carbon and environmental protection requirements.

[0003] However, wood flour, lignocellulose, or lignin are natural polymers containing a large number of hydroxyl groups and other organic groups, resulting in poor compatibility with polyolefin resins. Furthermore, without lubricants, the entire system suffers from poor internal and external lubrication, making extrusion difficult. Currently, the industry commonly uses small-molecule waxes such as hydrocarbon waxes, fatty acids, fatty acid esters, metal soaps, and fatty amides as lubricants. These lubricants generally suffer from precipitation problems at high temperatures and do not enhance the hydrophobic and oleophobic properties of wood-plastic composites.

[0004] Wood-plastic composite lubricants have been reported in the literature, and most of them are small-molecule waxes such as hydrocarbon waxes, fatty acids, fatty acid esters, metal soaps, and fatty amides, as well as their complexes. For example, patent CN111448259A discloses a wax composition as a lubricant for the production of wood-plastic composites. It uses a mixture of wax hydrocarbons and oxidized wax hydrocarbons as a lubricant for wood-plastic composites. This combination has a general lubrication effect and is difficult to extrude when the wood flour content is high.

[0005] For example, patent CN102408552A discloses an internal lubricant for wood-plastic composite materials. It is prepared by reacting glycerol, terephthaloyl chloride, polyethylene glycol-200 and dodecyl stearic acid under the catalysis of stannous chloride. This lubricant lacks external lubrication effect and is prone to peeling during extrusion.

[0006] For example, patent CN104710674A discloses a special lubricant for polyolefin wood-plastic composites, which is prepared by melt complexing zinc stearate, ethylene bis-stearamide, glyceryl monostearate, polyethylene wax, polyether wax and stearic acid. The lubricating effect of this lubricant is generally poor, and there is a risk of precipitation under high temperature boiling water.

[0007] For example, patent CN102504098A discloses a lubricant for wood-plastic composites prepared using gutter oil. It first dissolves acrylic acid in dodecyl stearic acid to obtain an esterification product, and then adds gutter oil and polyethylene polyamine to the obtained esterification product to react and obtain the lubricant. This lubricant has a small molecular weight and is at risk of precipitation when boiled in high temperature water.

[0008] For example, patent CN103265818A discloses a composite lubricant for wood-plastic composite materials. It is prepared by mixing ethylene bis-fatty acid amide, zinc stearate, stearic acid, maleic anhydride grafted polyethylene, polyethylene wax, oxidized polyethylene wax, monoglyceride, pentaerythritol stearate and a polymeric dispersant. This type of lubricant has the problem that the large number of mixed types can easily cause poor compatibility between waxes, leading to precipitation and extrusion problems.

[0009] For example, patent CN103589180A discloses a lubricant for wood-plastic composite materials. It first reacts dodecyl stearic acid and methacrylic acid to obtain an esterified product, and then reacts the esterified product with polyethylene polyamine and rapeseed oil to obtain a lubricant. This lubricant is a liquid oil-like lubricant and has the risk of precipitation.

[0010] For example, patent CN104788852A discloses a lubricant for wood-plastic composite materials, which is prepared by mixing high fatty alcohol, lubricant, maleic anhydride and / or maleic anhydride grafted polymer, inorganic filler and polymeric dispersant. The lubricant has relatively poor processing lubricity and may affect the appearance of the parts during extrusion.

[0011] For example, patent CN109206936A discloses a lubricant for wood-plastic extrusion, which is prepared by mixing stearate, diamine diamide, silicone powder, stearic acid monohydric anhydride, polypentyl tetraethylene stearate, fluorinated graphite, and antioxidant. This lubricant has a general lubrication effect and is prone to precipitation when boiled in water at high temperature.

[0012] For example, patent CN110628229A discloses a non-precipitating lubricant, which is obtained by mixing maleic anhydride-grafted polyethylene, maleic anhydride-grafted polypropylene, ethylene bis-stearamide, ethylene bis-oleamide, glyceryl monostearate, beeswax, polyethylene wax, oxidized polyethylene, and dimethyl silicone oil and then subjecting them to high-temperature oxidation. The dimethyl silicone oil used in this patent has poor compatibility with wood flour and resin and has almost no effect, which may cause a reduction in mechanical properties.

[0013] For example, patent CN102977455A discloses a lubricant for wood-plastic composites. The lubricant is prepared by catalytic reaction of 12-hydroxystearic acid, pentaerythritol, dibutyltin dilaurate, toluene diisocyanate, dimethylformamide and xylene. This lubricant contains highly polar urethane bonds that have a strong binding ability with wood flour, which makes the external lubrication effect of the lubricant weak and not conducive to the extrusion of wood-plastic composites. Summary of the Invention

[0014] The technical problem solved by this invention:

[0015] This invention addresses the problems of poor compatibility between wood flour particles and polyolefin resin, poor processing lubricity, and lubricant precipitation in wood-plastic composites. It also solves the problems of difficult extrusion and poor processing performance of wood-plastic composites.

[0016] The technical solution adopted in this invention is as follows:

[0017] To address the aforementioned technical problems, the present invention aims to provide a processing aid for wood-plastic composite materials and its preparation method. This application uses modified polysiloxane to compound with other wax-based lubricants to prepare a lubricant for wood-plastic composite materials. Small-molecule wax-based lubricants exhibit excellent lubrication effects during processing, but they pose a risk of precipitation. Compounding with modified polysiloxane prevents the precipitation of small-molecule lubricants, thus synergizing their advantages, resulting in a mixed lubricant with excellent performance. The processing aid provided by this invention enables wood powder to be fully dispersed in polyolefin resin, effectively increasing the mechanical properties of wood-plastic composite materials. Compounding modified polysiloxane with other waxes effectively combines the properties of modified polysiloxane with those of other waxes, resulting in a mixed lubricant that provides both internal and external lubrication while maintaining a low price, demonstrating excellent performance in the processing and extrusion of wood-plastic composite materials. Finally, compounding modified polysiloxane with other waxes in a specific ratio yields a low-cost, high-quality lubricant.

[0018] The details are as follows:

[0019] First, the present invention provides a processing aid for wood-plastic composite materials, wherein each component, by weight, includes 5-95 parts of modified polysiloxane, 5-95 parts of hydrocarbon wax, 5-95 parts of fatty acid, 5-95 parts of carboxylic acid ester, 5-95 parts of fatty amide, 5-95 parts of fatty alcohol, 5-95 parts of metallic soap, and 1-5 parts of other additives.

[0020] Second, the present invention provides a method for preparing the aforementioned processing aid for wood-plastic composite materials, comprising the following steps:

[0021] S1 modified polysiloxane, hydrocarbon wax, fatty acid, carboxylic ester, fatty amide, fatty alcohol, metal soap, and other additives are blended to obtain a mixture.

[0022] The S2 mixture is granulated by melt droplet granulation to obtain a processing aid for wood-plastic composite materials.

[0023] The technical mechanism employed in this invention is as follows:

[0024] The processing aid provided by this invention can significantly improve the processing performance of wood-plastic composites. A lubricant for wood-plastic composites is prepared by compounding modified polysiloxane with other wax-based lubricants. While small-molecule wax-based lubricants have excellent lubrication effects during processing, they pose a risk of precipitation. Compounding them with modified polysiloxane prevents the precipitation of small-molecule lubricants, resulting in a synergistic effect and superior performance of the mixed lubricant. The structural advantage of the polar groups in the modified polysiloxane provides good coating for wood flour particles that adsorb polar small-molecule lubricants, preventing some of these lubricants from migrating and precipitating. Furthermore, the polyolefin structure allows for entanglement with the polyolefin resin, achieving good compatibility. This ensures that the entire compounded lubricant system has no risk of precipitation. No precipitation occurs after high-temperature boiling, ensuring the dimensional integrity of the extruded parts and offering high cost-effectiveness.

[0025] The beneficial effects achieved by this invention are as follows:

[0026] Specifically, the processing aids used in this application have the following characteristics:

[0027] (1) It has excellent lubrication effect when used in wood-plastic composites;

[0028] (2) Composite lubricant can fully disperse wood powder in polyolefin resin, which can effectively increase the mechanical properties of wood-plastic composite materials;

[0029] (3) Small molecule wax lubricants have excellent lubrication effect during processing, but there is a risk of precipitation. When combined with modified polysiloxane, the small molecule lubricant does not precipitate, thus the advantages are superimposed and the mixed lubricant has excellent performance.

[0030] (4) The structural advantage of the polar groups in the modified polysiloxane has a good coating effect on the wood flour particles that adsorb polar small molecule lubricants, so that some polar small molecule lubricants will not migrate outward and precipitate. The structural part of the polyolefin can also achieve good compatibility with the polyolefin resin through entanglement. This makes the entire lubricant system after compounding free from the risk of precipitation.

[0031] (5) The composite lubricant provided in this application is simple to prepare, environmentally friendly, and low in cost. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0033] The purpose of this invention is to provide a processing aid for wood-plastic composite materials and a method for its preparation. Specifically,

[0034] First, the present invention provides a processing aid for wood-plastic composite materials, wherein each component, by weight, includes 5-95 parts of modified polysiloxane, 5-95 parts of hydrocarbon wax, 5-95 parts of fatty acid, 5-95 parts of carboxylic acid ester, 5-95 parts of fatty amide, 5-95 parts of fatty alcohol, 5-95 parts of metallic soap, and 1-5 parts of other additives.

[0035] Furthermore, each component, by weight, includes 10-95 parts modified polysiloxane, 10-95 parts hydrocarbon wax, 10-95 parts fatty acid, 10-95 parts carboxylic acid ester, 10-95 parts fatty amide, 10-95 parts fatty alcohol, 10-95 parts metallic soap, and 1-5 parts other additives.

[0036] Furthermore, the structural formula of the modified polysiloxane is shown in (I):

[0037]

[0038] R1, R2, R3, R4, R5, R6, R7, and R8 are independent monovalent organic groups or atoms; a, b, and c are integers greater than 4.

[0039] The structures of the monovalent organic groups R2 and R8 are one or more of the general formulas (I-1) or (I-2).

[0040] ——C r H (2r+1) (I-1)

[0041] ——CH2CH2CH2O(CH2CH2O) m [CH2CH(CH3)O] n R9 (I-2)

[0042] Where r, m, and n are integers greater than 1, and R9 is one of hydrogen atom, methoxy group, epoxy group, vinyl group, and hydroxyl group;

[0043] R1, R3, R5, and R7 are independent atoms or groups such as methyl, ethyl, propyl, phenyl, vinyl, hydroxyl, and hydrogen atoms.

[0044] R4 and R6 are long-chain organic groups containing polar structures. Specifically, they can be long-chain polyether groups, long-chain polyester groups, long-chain polyamide groups, long-chain polyacrylic acid groups, long-chain polyacrylate groups, long-chain polymethyl methacrylate groups, long-chain polystyrene groups, long-chain polyurethane groups, long-chain polyacrylic acid-styrene groups, long-chain polyacrylate-styrene groups, long-chain polymethyl methacrylate-styrene groups, long-chain polyacrylamide groups, long-chain polyacrylol groups, long-chain polyacrylamide-styrene groups, long-chain polyacrylamide-methyl acrylate groups, long-chain polyacrylamide-methyl methacrylate groups, long-chain polyacrylamide-maleic anhydride groups, long-chain polystyrene-maleic anhydride groups, long-chain polymethyl methacrylate-maleic anhydride groups, or long-chain polymethyl methacrylate-maleic anhydride groups.

[0045] This patent utilizes modified polysiloxanes combined with other lubricants to prepare a high-performance, low-cost hybrid lubricant. The modified polysiloxanes contain both plastic-friendly and wood-powder-friendly components, exhibiting a certain compatibilizing effect. While small-molecule lubricants provide good lubrication in wood-plastic processing, they pose a risk of precipitation. Simultaneously, the polar groups in the modified polysiloxanes effectively coat the wood-powder particles adsorbing polar small-molecule lubricants, preventing some of these lubricants from migrating and precipitating. Furthermore, the polyolefin structure allows for entanglement with the polyolefin resin, achieving excellent compatibility. This ensures the entire lubricant system is free from the risk of precipitation. Moreover, the silicone-based molecular structure possesses the unique properties of silicone, and when combined with other lubricants, it achieves both internal and external lubrication, offering high cost-effectiveness, no precipitation, and excellent processing lubrication and a defect-free product extrusion appearance.

[0046] Furthermore, the modified polysiloxane is prepared by the following steps:

[0047] Step 1: First, prepare cyclosiloxanes containing different groups;

[0048] Step 2: Then, ring-opening polymerization is carried out on cyclosiloxanes containing different groups, octamethylcyclotetrasiloxane, end-capping agents and catalysts to obtain co-modified polysiloxanes with different groups.

[0049] In this invention, the structures of cyclosiloxanes containing different groups are shown in general formulas (II) and (III):

[0050]

[0051] The structures of R2 and R8 are one or both of the general formulas (1-1) or (1-2).

[0052] R4 and R6 are long-chain organic groups containing polar structures or groups. Specifically, they can be long-chain polyether groups, long-chain polyester groups, long-chain polyamide groups, long-chain polyacrylic acid groups, long-chain polyacrylate groups, long-chain polymethyl methacrylate groups, long-chain polystyrene groups, long-chain polyurethane groups, long-chain polyacrylic acid-styrene groups, long-chain polyacrylate-styrene groups, long-chain polymethyl methacrylate-styrene groups, long-chain polyacrylamide groups, long-chain polyacrylol groups, long-chain polyacrylamide-styrene groups, long-chain polyacrylamide-methyl acrylate groups, long-chain polyacrylamide-methyl methacrylate groups, long-chain polyacrylamide-maleic anhydride groups, long-chain polystyrene-maleic anhydride groups, long-chain polymethyl methacrylate-maleic anhydride groups, or long-chain polymethyl methacrylate-maleic anhydride groups.

[0053] In this invention, the capping agent is hexamethyldisiloxane;

[0054] In this invention, the catalyst for ring-opening polymerization is one or more of sodium hydroxide, potassium hydroxide, sodium hydride, potassium hydride, tetramethylammonium hydroxide, and tetrabutylammonium hydroxide;

[0055] In this invention, the temperature range for ring-opening polymerization is 100–200°C;

[0056] In this invention, the amount of catalyst used for ring-opening polymerization is 0.1% to 2% of the total mass of the reaction substances;

[0057] In this invention, the reaction molar ratio of cyclosiloxanes containing different groups, octamethylcyclotetrasiloxane, and end-capping agent is 10-99:10-99:1-40;

[0058] In this invention, cyclosiloxanes containing different groups are prepared by catalytic reaction of hydrogen-containing cyclosiloxanes with unsaturated groups; the catalyst used for the catalytic reaction is a platinum catalyst; the preparation temperature is 70-200℃; and the amount of catalyst used is 0.1-2% of the total mass of the reaction substances.

[0059] In this invention, the hydrocarbon wax includes at least one of polyethylene wax, chlorinated polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, paraffin wax, Fischer-Tropsch wax, and montana wax.

[0060] In this invention, the fatty acids include at least one of stearic acid, oleic acid, erucic acid, nonanoic acid, palmitic acid, and myristic acid.

[0061] In this invention, the carboxylic acid ester includes at least one of glyceryl monostearate, glyceryl oleate, and glyceryl erucate.

[0062] In this invention, fatty amides include at least one of erucamide, oleamide, stearamide, ethylene bis-stearamide, ethylene bis-oleamide, and octadecyl erucamide.

[0063] In this invention, fatty alcohols include at least one selected from octadecyl alcohol, hexadecyl alcohol, polyethylene glycol, and polyethylene glycol derivatives. Specifically, polyethylene glycol derivatives include at least one selected from polyethylene glycol monolaurate and polyethylene glycol dimethacrylate.

[0064] In this invention, the metal soap includes at least one of lead stearate, zinc stearate, calcium stearate, magnesium stearate, aluminum stearate, sodium stearate, lithium stearate, lead oleate, zinc oleate, calcium oleate, sodium oleate, and lead erucic acid.

[0065] In this invention, other additives include at least one of antioxidants, antistatic agents, UV stabilizers, and antibacterial agents; wherein:

[0066] Antioxidants include at least one of the following: 3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylate, N-phenyl-α-naphthylamine, alkylphenthiazide, benzotriazole, mercaptobenzothiazide, 2,6-di-tert-butyl-p-cresol, N-cyclohexyl-N'-phenyl-p-phenylenediamine, triphenyl phosphite, diphenyl-isooctyl phosphite, and tributyl phosphite;

[0067] UV stabilizers include at least one of o-hydroxybenzoate, 2,2',4,4'-tetrahydroxybenzophenone, and 2-(2,hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorophenyltriazole;

[0068] Antibacterial agents include at least one of the following: silver ion antibacterial agents, zinc oxide, copper oxide, ammonium dihydrogen phosphate, lithium carbonate, sodium pentachlorophenate, p-nitrophenol, glutaraldehyde, and ethylene glycol methyl ether.

[0069] Antistatic agents include at least one of alkyl quaternary ammonium salts, sodium alkyl sulfonates, and ethoxy aliphatic alkylamines. Specifically, ethoxy aliphatic alkylamines can be ethoxylaurylamine or glyceryl stearate.

[0070] Second, the present invention provides a method for preparing the aforementioned processing aid for wood-plastic composite materials, comprising the following steps:

[0071] S1 modified polysiloxane, hydrocarbon wax, fatty acid, carboxylic ester, fatty amide, fatty alcohol, metal soap, and other additives are blended to obtain a mixture.

[0072] The S2 mixture is granulated by melt droplet granulation to obtain a processing aid for wood-plastic composite materials.

[0073] <Example>

[0074] Example 1

[0075] A processing aid for wood-plastic composite materials and its preparation method are disclosed. The components of the processing aid are as follows: by weight, modified polysiloxane 1:20 parts, paraffin wax: 30 parts, erucic acid: 10 parts, glyceryl monostearate: 10 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts; benzotriazole: 1 part, ammonium dihydrogen phosphate: 1 part.

[0076] Modified polysiloxane 1, paraffin wax, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then processed into wood-plastic composite material processing aid 1 by melt drop granulation.

[0077] The modified polysiloxane 1 has the following structure:

[0078]

[0079] The preparation method of modified polysiloxane 1 is as follows:

[0080] Raw material 1 or raw material 2 is reacted with tetramethylcyclotetrasiloxane (molar ratio of 4:1) at a certain temperature (reaction stage 1), and then a catalyst is added dropwise to continue the reaction (reaction stage 2) to obtain modified product 1-1 or modified product 1-2.

[0081] The first stage of the reaction was carried out at 60°C for 1 hour; the catalyst was 0.1% chloroplatinic acid by total mass; the second stage of the reaction was carried out by stirring for 8 hours.

[0082] That is, modified compound 1-1 is prepared using α-dodecene as raw material 1; and modified compound 1-2 is prepared using allyl polyoxyethylene polyoxypropylene ether as raw material 2.

[0083] Modified compound 1-1, octamethylcyclotetrasiloxane, modified compound 1-2, and hexamethyldisiloxane (molar ratio 4:4:4:1) were stirred at 100℃ for 1 h. After stirring until homogeneous, 0.5% of tetramethylammonium hydroxide was slowly added and stirred for 0.5 h. Then the temperature was raised to 150℃ and the reaction continued for 8 h. After the reaction was completed, the temperature was raised to 180℃ and the pressure was reduced for 2 h to obtain modified polysiloxane additive 1.

[0084] Example 2

[0085] A processing aid for wood-plastic composite materials and its preparation method are disclosed. The components of the processing aid are as follows: by weight, modified polysiloxane 1:30 parts, paraffin wax 20 parts, erucic acid 10 parts, glyceryl monostearate 10 parts, erucamide 10 parts, polyethylene glycol 10 parts, calcium stearate 8 parts, benzotriazole 1 part, and ammonium dihydrogen phosphate 1 part.

[0086] Modified polysiloxane 1, paraffin wax, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 2 for wood-plastic composite materials.

[0087] The structure and preparation method of the modified polysiloxane 1 are the same as those in Example 1.

[0088] Example 3

[0089] A processing aid for wood-plastic composite materials and its preparation method are disclosed. The components of the processing aid are as follows: by weight, modified polysiloxane 1:40 parts, paraffin wax: 10 parts, erucic acid: 10 parts, glyceryl monostearate: 10 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts, benzotriazole: 1 part, and ammonium dihydrogen phosphate: 1 part.

[0090] Modified polysiloxane 1, paraffin wax, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 3 for wood-plastic composite materials.

[0091] The structure and preparation method of the modified polysiloxane 1 are the same as those in Example 1.

[0092] Example 4

[0093] A processing aid for wood-plastic composite materials and its preparation method are disclosed. The components of the processing aid are as follows: by weight, modified polysiloxane 2: 20 parts, paraffin: 30 parts, erucic acid: 10 parts, glyceryl monostearate: 10 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts, benzotriazole: 1 part, and ammonium dihydrogen phosphate: 1 part.

[0094] Modified polysiloxane 2, paraffin, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 4 for wood-plastic composite materials.

[0095] The modified polysiloxane 2 has the following structure:

[0096]

[0097] The preparation method of modified polysiloxane 2 is as follows:

[0098] The difference between this and modified polysiloxane 1 is that the molar ratio of modified product 1-1, octamethylcyclotetrasiloxane, modified product 1-2, and hexamethyldisiloxane is 1:10:1:1.

[0099] Example 5

[0100] A processing aid for wood-plastic composite materials and its preparation method are disclosed. The components of the processing aid are as follows: by weight, modified polysiloxane 2: 30 parts, paraffin wax: 20 parts, erucic acid: 10 parts, glyceryl monostearate: 10 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts, benzotriazole: 1 part, and ammonium dihydrogen phosphate: 1 part.

[0101] Modified polysiloxane 2, paraffin, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 5 for wood-plastic composite materials.

[0102] The structure and preparation method of the modified polysiloxane 2 are the same as in Example 4.

[0103] Example 6

[0104] A processing aid for wood-plastic composite materials and its preparation method are disclosed. The components of the processing aid are as follows: by weight, modified polysiloxane 2: 40 parts, paraffin wax: 10 parts, erucic acid: 10 parts, glyceryl monostearate: 10 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts, benzotriazole: 1 part, and ammonium dihydrogen phosphate: 1 part.

[0105] Modified polysiloxane 2, paraffin, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 6 for wood-plastic composite materials.

[0106] The structure and preparation method of the modified polysiloxane 2 are the same as in Example 4.

[0107] <Comparative Example>

[0108] Comparative Example 1

[0109] A processing aid for wood-plastic composites was prepared by replacing modified polysiloxane with dimethyl silicone oil with a polymer chain length of 40. The components of the processing aid are as follows: by weight, dimethyl silicone oil: 20 parts, paraffin wax: 30 parts, erucic acid: 10 parts, glyceryl monostearate: 10 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts, benzotriazole: 1 part, and ammonium dihydrogen phosphate: 1 part.

[0110] Dimethyl silicone oil, paraffin wax, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 7 for wood-plastic composite materials.

[0111] Comparative Example 2

[0112] A processing aid for wood-plastic composites was prepared by replacing modified polysiloxane with dimethyl silicone oil with a polymer chain length of 40. The components of the processing aid are as follows: by weight, dimethyl silicone oil: 30 parts, paraffin wax: 20 parts, erucic acid: 10 parts, glyceryl monostearate: 10 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts, benzotriazole: 1 part, and ammonium dihydrogen phosphate: 1 part.

[0113] Dimethyl silicone oil, paraffin wax, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 8 for wood-plastic composite materials.

[0114] Comparative Example 3

[0115] A processing aid for wood-plastic composites was prepared by replacing modified polysiloxane with dimethyl silicone oil with a polymer chain length of 40. The components of the processing aid are as follows: by weight, dimethyl silicone oil: 40 parts, paraffin wax: 10 parts, erucic acid: 10 parts, glyceryl monostearate: 10 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts, benzotriazole: 1 part, and ammonium dihydrogen phosphate: 1 part.

[0116] Dimethyl silicone oil, paraffin wax, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 9 for wood-plastic composite materials.

[0117] Comparative Example 4

[0118] Paraffin wax was used to replace modified polysiloxane in the preparation of a wood-plastic processing aid. The components of the processing aid are as follows: by weight, paraffin wax: 50 parts, erucic acid: 10 parts, glyceryl monostearate: 10 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts, benzotriazole: 1 part, and ammonium dihydrogen phosphate: 1 part.

[0119] Paraffin wax, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 10 for wood-plastic composite materials.

[0120] Comparative Example 5

[0121] Erucic acid was replaced with modified polysiloxane to prepare a processing aid for wood-plastic composites. The components of the processing aid are as follows: by weight, paraffin wax: 30 parts, erucic acid: 30 parts, glyceryl monostearate: 10 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts, benzotriazole: 1 part, and ammonium dihydrogen phosphate: 1 part.

[0122] Paraffin wax, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 11 for wood-plastic composite materials.

[0123] Comparative Example 6

[0124] The modified polysiloxane was replaced with glyceryl monostearate to prepare a processing aid for wood-plastic composites. The components of the processing aid are as follows: by weight, paraffin wax: 30 parts, erucic acid: 10 parts, glyceryl monostearate: 30 parts, erucamide: 10 parts, polyethylene glycol: 10 parts, calcium stearate: 8 parts, benzotriazole: 1 part, and ammonium dihydrogen phosphate: 1 part.

[0125] Paraffin wax, erucic acid, glyceryl monostearate, erucamide, polyethylene glycol, calcium stearate, benzotriazole, and ammonium dihydrogen phosphate were added to a reaction vessel in proportion, melted and mixed evenly, and then granulated by droplet to obtain processing aid 12 for wood-plastic composite materials.

[0126] <Experimental Example>

[0127] The processing aids 1-6 for wood-plastic composite materials prepared in Examples 1-6 and the processing aids 7-12 for wood-plastic composite materials prepared in Comparative Examples 1-6 were used as test samples for testing.

[0128] Tests on the processing and extrusion properties of wood-plastic composite materials

[0129] 1. The test sample was added to the wood-plastic composite material, granulated using a twin-screw extruder, the lubrication effect was tested using a torque rheometer, the extrusion performance was examined by extruding sheets using a single screw, and the water boiling precipitation test was conducted. The formulation is shown in Table 1.

[0130] Table 1 Raw material ratios for wood-plastic composite materials

[0131]

[0132] 2. The test results of wood-plastic composite materials are shown in Table 2.

[0133] Note: The lubrication effect of the torque rheometer was measured at 180℃ and 60rpm; the extrusion performance was measured at 180℃ and 80rpm; and the water resistance test was measured at 80℃ and 72h.

[0134] Table 2. Test results of processing and extrusion performance of wood-plastic composite materials

[0135]

[0136] In summary, the processing aid provided by this invention can significantly improve the processing performance of wood-plastic composites when applied to wood-plastic composites, ensuring the integrity of the appearance of wood-plastic composite extruded parts; at the same time, it does not precipitate during high-temperature boiling.

[0137] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A processing aid for wood-plastic composite materials, characterized in that, The components, by weight, include 20-95 parts modified polysiloxane, 10-95 parts hydrocarbon wax, 5-10 parts fatty acid, 5-10 parts carboxylic acid ester, 5-10 parts fatty amide, 5-10 parts polyethylene glycol or polyethylene glycol derivative, 5-8 parts metal soap, and 1-5 parts other additives. The structural formula of the modified polysiloxane is shown in (I): （I） a, b, and c are integers greater than 4; R1, R2, R3, R5, R6, and R7 are methyl groups; R4 is ; The structure of R8 is as shown in general formula (I-1). （I-1） Where r is an integer greater than 1.

2. The processing aid for wood-plastic composite materials according to claim 1, characterized in that, Each component of the processing aid includes at least one of features (1) to (5): (1) Hydrocarbon waxes include at least one of polyethylene wax, chlorinated polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, paraffin wax, Fischer-Tropsch wax, and montana wax; (2) Fatty acids include at least one of stearic acid, oleic acid, erucic acid, nonanoic acid, palmitic acid, and myristic acid; (3) Carboxylic acid esters include at least one of glyceryl monostearate, glyceryl oleate, and glyceryl erucate; (4) Fatty amides include at least one of erucamide, oleamide, stearamide, ethylene bis-stearamide, ethylene bis-oleamide, and octadecyl erucamide; (5) Metal soaps include at least one of lead stearate, zinc stearate, calcium stearate, magnesium stearate, aluminum stearate, sodium stearate, lithium stearate, lead oleate, zinc oleate, calcium oleate, sodium oleate, and lead erucic acid.

3. The processing aid for wood-plastic composite materials according to claim 1, characterized in that, Other additives include at least one of antioxidants, antistatic agents, UV stabilizers, and antibacterial agents; other additives include at least one of features (1) to (4): (1) Antioxidants include at least one of the following: 3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylate, N-phenyl-α-naphthylamine, alkylphenthiazide, benzotriazole, mercaptobenzothiazide, 2,6-di-tert-butyl-p-cresol, N-cyclohexyl-N'-phenyl-p-phenylenediamine, triphenyl phosphite, diphenyl-isooctyl phosphite, and tributyl phosphite; (2) The UV stabilizer includes at least one of o-hydroxybenzoate, 2,2',4,4'-tetrahydroxybenzophenone, and 2-(2,hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorophenyltriazole; (3) The antibacterial agent includes at least one of the following: silver ion antibacterial agent, zinc oxide, copper oxide, ammonium dihydrogen phosphate, lithium carbonate, sodium pentachlorophenate, p-nitrophenol, glutaraldehyde, and ethylene glycol methyl ether; (4) The antistatic agent includes at least one of alkyl quaternary ammonium salt, sodium alkyl sulfonate, and ethoxy aliphatic alkylamine.

4. The processing aid for wood-plastic composite materials according to claim 1, characterized in that, The modified polysiloxane is prepared by introducing a modifying group into a cyclosiloxane to obtain a modified cyclosiloxane, which is then reacted with octamethylcyclotetrasiloxane, a capping agent and a catalyst to obtain the modified polysiloxane.

5. The processing aid for wood-plastic composite materials according to claim 4, characterized in that, The reaction molar ratio of modified cyclosiloxane, octamethylcyclotetrasiloxane and end-capping agent is 10~99:10~99:1~40.

6. A method for preparing a processing aid for wood-plastic composite materials as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1 modified polysiloxane, hydrocarbon wax, fatty acid, carboxylic ester, fatty amide, fatty alcohol, metal soap, and other additives are blended to obtain a mixture. The S2 mixture is granulated by melt droplet granulation to obtain a processing aid for wood-plastic composite materials.

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