Bending-resistant polyvinyl chloride foaming co-extrusion composite material and preparation method thereof

Abstract

The invention provides a bending-resistant polyvinyl chloride foaming co-extrusion composite material and a preparation method thereof, and belongs to the technical field of polyvinyl chloride composite materials. The composite material is mainly obtained by co-extruding a co-extrusion surface layer and a core layer, wherein the surface layer is composed of ASA resin, chlorinated polyether and color masterbatch; the core layer is prepared from polyvinyl chloride resin, calcium carbonate, glass fiber gridding cloth, melamine-1, 3-bis (4 '-aminophenoxy) benzaldehyde resin powder, carboxyl polyester resin, a heat stabilizer, a foaming agent, a lubricating agent, a coupling agent and color masterbatch. The composite material has excellent wear resistance and high long-span bending strength, and is suitable for outdoor weather resistance, wear resistance and long span.

Description

Technical Field

[0001] The invention belongs to the technical field of polyvinyl chloride composite materials, and particularly relates to a long-span anti-bending polyvinyl chloride foamed co-extruded composite material and a preparation method thereof. Background Art

[0002] The current composite flooring market mainly includes wood-plastic composite flooring, pure wood materials such as wooden flooring, and ordinary wood particle laminate flooring. Among them, wooden flooring or ordinary wood particle laminate flooring cannot be used outdoors due to exposure to rain and other factors. Therefore, outdoor decoration mainly uses wood-plastic composite materials. However, because wood-plastic materials contain a large amount of wood powder, they are prone to mold, degradation, and rot when used outdoors. All-plastic composite materials that do not use wood powder can solve the defects of traditional wood-plastic composite materials such as mold and degradation. However, they are difficult to promote due to problems such as excessive density, heavy unit weight, and high cost. The purpose of reducing the density of all-plastic composite materials, reducing unit weight, and lowering the cost of plastic use can be achieved by using a foaming process. However, while the foaming process reduces weight, the presence of bubbles inside the plastic leads to a decrease in the product's flame retardancy and mechanical flexural strength.

[0003] Compared to plastics like polystyrene, PE, and PP, polyvinyl chloride (PVC) boasts a high chlorine content, reasonable cost, and flame retardancy. Research and market adoption of foamed PVC composites have been rapid in recent years. However, due to their insufficient flexural strength, foamed PVC composites are prone to intermediate deformation, particularly when used over long spans (e.g., spans of 350mm and above). This makes them unsuitable for load-bearing flooring applications with high bending resistance requirements, particularly for spans greater than 350mm. Furthermore, since foamed PVC composite flooring is primarily intended for outdoor use, it also has high requirements for flame retardancy, weather resistance, and surface wear resistance. Developing a product that meets these requirements through the integration of the surface and core layers presents a challenge. Summary of the Invention

[0004] In response to the above problems, the present invention provides a bending-resistant polyvinyl chloride foam co-extruded composite material and a preparation method. The composite material has excellent wear resistance and high long-span bending strength, and is suitable for outdoor weather resistance, wear resistance, and long-span requirements.

[0005] One of the purposes of the present invention is to provide a bending-resistant polyvinyl chloride foam co-extruded composite material.

[0006] A second object of the present invention is to provide a method for preparing the anti-bending polyvinyl chloride foam co-extruded composite material.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted: In a first aspect, the present invention provides a bending-resistant polyvinyl chloride foam co-extruded composite material, comprising a co-extruded surface layer and a core layer; the raw material mass ratio of the surface layer to the core layer is 0.5-0.8:10; and a reinforcement layer formed of a continuous glass fiber mesh cloth is further provided in the middle of the core layer; The raw materials for preparing the surface layer include the following components in parts by weight: 70-80 parts of ASA resin, 20-30 parts of chlorinated polyether, and 0.3-0.8 parts of ASA masterbatch; The raw materials for preparing the core layer include the following components in parts by weight: 65-80 parts of polyvinyl chloride resin, 20-25 parts of modified calcium carbonate, 3-5 parts of heat stabilizer, 0.4-0.6 parts of lubricant, 0.8-1.0 parts of coupling agent, 0.7-1.1 parts of foaming agent, 10-13 parts of modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin, 3-4 parts of carboxyl polyester resin, and 0.1-0.3 parts of PVC masterbatch; The glass fiber mesh is a glass fiber mesh treated with methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive; The modified calcium carbonate is calcium carbonate modified by methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive.

[0008] The following details are provided: Topping: Typical but non-limiting parts by weight of ASA resin are, for example, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 parts.

[0009] Chlorinated polyether can use the model 4023 product of American Liquid Nitrogen Processing Company, injection molding grade, particle size, 50-60 mesh; Typical but non-limiting amounts of the chlorinated polyether are, for example, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 parts by weight.

[0010] ASA masterbatch includes ASA masterbatch of conventional colors such as red, yellow, glaze color, etc. Typical but non-limiting weight amounts of ASA masterbatch are, for example, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8 parts.

[0011] Core layer: The methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive was prepared by the following method: (1) Add 37% (mass fraction) formaldehyde aqueous solution and methanol into the reactor, start stirring and stir evenly, then use 10-15% (mass fraction) sodium hydroxide aqueous solution to adjust the pH value of the system to 8.0-9.0, then add melamine and 1,3-bis(4'-aminophenoxy)benzene, and heat to 65-70°C for insulation polymerization reaction; the molar ratio of the raw materials is melamine: 1,3-bis(4'-aminophenoxy)benzene: formaldehyde (pure formaldehyde): methanol = 1: 0.3-0.4: 7.5-8.8: 2.5-3.0; (2) After the reaction system has no insoluble matter and becomes homogeneous, cool it to 40-50°C, add concentrated sulfuric acid to adjust the pH value to 3.0-4.0, and continue the polymerization reaction at this temperature; (3) Sampling and testing: when the viscosity of the system is 120-140 mPa.s, add 10-15% (mass fraction) sodium hydroxide aqueous solution to adjust the pH value of the system to 9.0-10.0, increase the temperature and perform reduced pressure distillation, with the vacuum degree controlled at -0.096 to -0.098 MPa and the distillation temperature at 90-95°C; (4) Sampling and testing the volatile content of the reactants in step (3). When the volatile content is 30-35%, a methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive is obtained.

[0012] The modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin was prepared by the following method: (1) Add 37% (mass fraction) formaldehyde aqueous solution and methanol into the reactor, start stirring and stir evenly, then use 10-15% (mass fraction) sodium hydroxide aqueous solution to adjust the pH value of the system to 8.0-9.0, then add melamine and 1,3-bis(4'-aminophenoxy)benzene, and heat to 65-70°C for heat preservation polymerization reaction; the molar ratio of raw materials is melamine: 1,3-bis(4'-aminophenoxy)benzene: formaldehyde: methanol = 1: 0.3-0.4: 7.5-8.8: 2.5-3.0; (2) After the reaction system has no insoluble matter and becomes homogeneous, cool it to 40-50°C, add concentrated sulfuric acid to adjust the pH value to 3.0-4.0, and continue the polymerization reaction at this temperature; (3) Sampling and testing: when the viscosity of the system is 120-140 mPa.s, add 10-15% (mass fraction) sodium hydroxide aqueous solution to adjust the pH value of the system to 9.0-10.0, increase the temperature and perform reduced pressure distillation, with the vacuum degree controlled at -0.096 to -0.098 MPa and the distillation temperature at 90-95°C; (4) Sampling and testing the volatile content of the reactants in step (3). When the volatile content is 7-10%, the vacuum system is released, and hexahydroxymethylmelamine powder is added. After stirring and mixing, the material is released and placed in a vacuum oven for drying. The oven temperature is 85-90°C and the vacuum degree is -0.098 to -0.099 MPa. When the volatile content is less than 2%, the material is taken out and crushed into 60-80 mesh powder to obtain modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder, wherein the molar amount of hexahydroxymethylmelamine is 0.1-0.12 times the molar amount of melamine.

[0013] The polyvinyl chloride resin can be selected from Wanhua Chemical Group Co., Ltd.'s WH900 product, with a K value of 64; Typical but non-limiting weight amounts of polyvinyl chloride resin are, for example, 65, 66, 68, 70, 72, 74, 75, 76, 77, and 80 parts by weight.

[0014] Calcium carbonate uses nano-active calcium carbonate specially used for plastics, with a particle size of 200-300nm; Typical but non-limiting weight amounts of modified calcium carbonate are, for example, 20, 21, 22, 23, 24, or 25 parts.

[0015] The heat stabilizer is a complex of calcium stearate and zinc stearate, with a mass ratio of 2:1-1.3; Typical but non-limiting weight amounts of the heat stabilizer are, for example, 3, 4, or 5 parts.

[0016] The lubricant is stearic acid or hexadecanoic acid; Typical but non-limiting weight amounts of lubricant are, for example, 0.4, 0.5, or 0.6 parts.

[0017] The coupling agent is silane coupling agent JH-M902 or silane coupling agent KH-540; Typical but non-limiting weight amounts of the coupling agent are, for example, 0.8, 0.9, or 1.0 parts.

[0018] The blowing agent is azodicarbonamide; Typical but non-limiting weight amounts of the blowing agent are, for example, 0.7, 0.8, 0.9, 1.0, or 1.1 parts.

[0019] Typical but non-limiting weight amounts of the modified melamine-1,3-bis(4′-aminophenoxy)benzaldehyde resin are, for example, 10, 11, 12, or 13 parts.

[0020] The acid value of carboxyl polyester resin is 25-29 mgKOH / g, and the model GH-3305 product of Zhejiang Guanghua Technology Co., Ltd. can be selected; Typical but non-limiting weight amounts of the carboxyl polyester resin are, for example, 3, 3.5, or 4 parts.

[0021] PVC masterbatch includes PVC masterbatch in conventional colors such as red, yellow, glaze color, etc. Typical but non-limiting weight amounts of PVC masterbatch are, for example, 0.1, 0.2, or 0.3 parts.

[0022] Reinforcement layer: The specifications of the glass fiber mesh are 5mm×5mm and the weight is 130g / m 2 .

[0023] The methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive is the same as described above.

[0024] In a second aspect, the present invention provides a method for preparing the above-mentioned bending-resistant polyvinyl chloride foam co-extruded composite material, comprising the following steps: (1) ASA resin, chlorinated polyether and ASA masterbatch in the formula are fully mixed at room temperature, and then melt-extruded and granulated by a twin-screw extruder to obtain surface layer granules for standby use; (2) The formulated amount of polyvinyl chloride resin, calcium carbonate modified by methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive, heat stabilizer, lubricant, coupling agent, modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin, carboxyl polyester resin, foaming agent, and PVC masterbatch are first fully mixed at room temperature, and then crushed to a particle size of 70-100 mesh by a high-speed grinder to prepare a core layer premix for standby use; (3) Take the surface layer granular material and the core layer premix according to the mass ratio, melt the core layer premix and the surface layer granular material through different twin-screw extruders, and then enter the core layer cavity and the surface layer cavity of the co-extrusion mold respectively. A glass fiber mesh cloth treated with methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive is fixed in advance in the middle 1 / 2 of the core layer cavity. The core layer melt fills the core layer cavity and is fully combined with the glass fiber mesh cloth to complete the foaming and surface layer co-extrusion molding. After cooling molding, surface layer surface embossing treatment, and fixed length cutting, a bending-resistant polyvinyl chloride foam co-extruded composite material is obtained.

[0025] In some embodiments, in step (1), the barrel temperature of the twin-screw extruder is 240-250° C., and the screw speed is 150-200 rpm.

[0026] In some embodiments, in step (2), the method for preparing calcium carbonate modified with a methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive comprises: An automatic sprayer is used to spray a water-diluted methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive (solid content 30-35%) on the surface of calcium carbonate. The mass ratio of the adhesive (diluted with water) to calcium carbonate is 3-5:100. The calcium carbonate is continuously stirred during the spraying process to ensure uniform spraying. After the spraying is completed, it is fully mixed in a mixer for 10-15 minutes and then vacuum dried to obtain a modified calcium carbonate with a volatile matter of less than 1%.

[0027] In some embodiments, in step (3), the method for preparing the glass fiber mesh treated with a methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive comprises: Soak the glass fiber mesh in methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive for 20-30 seconds, hang it vertically at room temperature to dry until no liquid drops, hang it in an oven or drying room and use hot air for pre-curing treatment. The oven or drying room temperature is 80-85℃, the time is 10-15 minutes, and then cool to room temperature.

[0028] In some embodiments, in step (3), the conditions for extrusion molding of the core layer are: barrel temperature of 200 to 205°C, screw speed of 10 to 20 rpm; The conditions for the surface layer extrusion molding are: barrel temperature of 220-230°C and screw speed of 10-20 rpm.

[0029] Beneficial effects: The composite material of the invention is mainly obtained by co-extruding a surface layer and a core layer. The surface layer is composed of ASA resin, chlorinated polyether and masterbatch; the core layer is composed of polyvinyl chloride resin, calcium carbonate, glass fiber mesh cloth, melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder, carboxyl polyester resin, heat stabilizer, foaming agent, lubricant, coupling agent and masterbatch. The glass fiber mesh cloth with specific requirements is pre-dipped and sizing treated with methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzene copolymer formaldehyde resin adhesive. Then, during the polyvinyl chloride resin molding process, modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder and a specific carboxyl polyester resin are used to participate in the cross-linking and curing during the polyvinyl chloride resin foaming process. Hexafunctional hexahydroxymethyl melamine is introduced into the modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin, which not only greatly improves the cross-linking density, hardness and flexural strength of the foamed polyvinyl chloride composite material, but also improves the high-temperature deformation resistance of the core layer. The specific carboxyl polyester resin is used to adjust the mechanical properties of the composite material after foaming molding. At the same time, the simultaneous use of methylated melamine-1,3-bis(4'-aminophenoxy)benzene copolymer formaldehyde resin adhesive components and modified melamine-1,3-bis(4'-aminophenoxy)benzene copolymer formaldehyde resin achieves the co-curing of melamine-1,3-bis(4'-aminophenoxy)benzene copolymer formaldehyde resin, modified melamine-1,3-bis(4'-aminophenoxy)benzene copolymer formaldehyde resin, and carboxyl polyester resin on the surface of the glass fiber mesh cloth. This not only increases the bonding ability between the glass fiber mesh cloth and the polyvinyl chloride foam resin material layer, but also greatly enhances the bending resistance and flame retardancy brought about by the introduction of the glass fiber mesh cloth into the core layer. This can achieve a significant increase in bending strength with almost no significant weight gain, making it suitable for use in the field of long-span wood-plastic flooring. At the same time, the surface layer uses a composite material of chlorinated polyether and ASA resin. The introduction of specific dosage and type of chlorinated polyether improves the wear resistance, flame retardancy, and weather resistance of the surface material.

[0030] The present invention has been described in detail above, but the above embodiments are merely illustrative in nature and are not intended to limit the present invention. In addition, the present invention is not limited by any theory described in the above prior art or invention summary or the following examples. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the examples. It should be noted that the following examples are provided for illustrative purposes only and do not constitute a limitation on the scope of protection claimed in the present invention.

[0032] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, and methods in the art.

[0033] The raw material models, manufacturers / suppliers used in the examples are as follows: ASA resin, model HM-957, injection molding grade, Qingdao Zhongxin Huamei Plastic Co., Ltd.; ASA masterbatch and PVC masterbatch are both from Qingdao Zhongxin Huamei Plastic Co., Ltd.; Chlorinated polyether, model 4023, injection molding grade, particle size, 50-60 mesh, American Liquid Nitrogen Processing Company; Glass fiber mesh cloth, mesh size 5mm×5mm, weight 130g / m 2 , Anhui Tianfu New Materials Co., Ltd.; Carboxyl polyester resin, model GH-3305, acid value 25-29 mgKOH / g, purchased from Zhejiang Guanghua Technology Co., Ltd. Calcium carbonate used is nano-active calcium carbonate for plastics, model SPSL-2, particle size 200-300nm, produced by Jiangxi Huaming Nano Calcium Carbonate Co., Ltd. Others are conventional raw materials.

[0034] Determination of volatile matter content and solid content: Take 10g of sample and put it into a beaker. Then put the beaker into a blast oven and dry it at 130℃ / 30min. Take it out and cool it to room temperature and weigh it again. The weight loss is the volatile matter. The volatile matter content is: . Solid content is 100% - volatile content. Preparation Example 1 Preparation of methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive: (1) Add 37% (mass fraction) formaldehyde aqueous solution (containing 8 mol of formaldehyde) and 3 mol of methanol into the reactor, start stirring and stir evenly, then use 12% (mass fraction) sodium hydroxide aqueous solution to adjust the pH value of the system to 8.5, then add 1 mol of melamine and 0.3 mol of 1,3-bis(4'-aminophenoxy)benzene, and heat to 70°C for heat preservation polymerization reaction; (2) After the reaction system has no insoluble matter and becomes homogeneous, cool it to 40°C, add concentrated sulfuric acid to adjust the pH to 3.5, and continue the polymerization reaction at this temperature; (3) Sampling and testing: when the viscosity of the system is 120-140 mPa.s, add 12% sodium hydroxide aqueous solution again to adjust the pH value of the system to 9.5, increase the temperature and perform reduced pressure distillation, with a vacuum degree of -0.098 MPa and a distillation temperature of 95°C; (4) Sampling and testing the volatile content of the reactants in step (3). When the volatile content is 32%, a methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive is obtained and set aside.

[0035] Preparation Example 2 Preparation of modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder: (1)-(3) are the same as those in Preparation Example 1; (4) Sampling and testing the volatile content of the reactants in step (3). When the volatile content is 9%, release the vacuum system, add 0.1 mol of hexahydroxymethyl melamine powder, stir and mix evenly, release the material, and place it in a vacuum oven for drying. The oven temperature is 90°C and the vacuum degree is -0.099 MPa. When the volatile content is less than 2%, take out the material and crush it into 60-80 mesh powder to obtain modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder.

[0036] Preparation Example 3 Preparation of calcium carbonate modified with methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive: An automatic sprayer is used to spray the methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive (solid content 30%) diluted with water on the surface of calcium carbonate. The mass ratio of the adhesive to calcium carbonate is 4:100. The calcium carbonate is continuously stirred during the spraying process to ensure uniform spraying. After the spraying is completed, it is fully mixed in a mixer for 10 minutes and then vacuum dried to obtain a modified calcium carbonate with a volatile matter of less than 1%.

[0037] Preparation Example 4 Preparation of glass fiber mesh treated with methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive: The glass fiber mesh was soaked in methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive for 30 seconds, hung vertically to dry at room temperature until no liquid dripped, and hung in an oven for pre-curing treatment at 85°C for 10 minutes, and then cooled to room temperature.

[0038] Example 1 A bending-resistant polyvinyl chloride foam co-extruded composite material, comprising a co-extruded surface layer and a core layer; the raw material mass ratio of the surface layer to the core layer is 0.65:10; a reinforcing layer formed by a glass fiber mesh cloth treated with a methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive is provided in the middle of the core layer; The raw materials for preparing the surface layer include the following components in parts by weight: ASA resin 70 parts, chlorinated polyether 30 parts, ASA masterbatch 0.3 parts; The raw materials for preparing the core layer include the following components in parts by weight: 75 parts of polyvinyl chloride resin, 20 parts of calcium carbonate modified with methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive, 4 parts of heat stabilizer (calcium stearate and zinc stearate in a mass ratio of 2:1), 0.5 parts of stearic acid as a lubricant, 1.0 parts of silane coupling agent JH-M902, 1 part of azodicarbonamide as a foaming agent, 10 parts of modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin, 3 parts of carboxyl polyester resin, and 0.1 parts of PVC masterbatch.

[0039] The method for preparing the composite material comprises the following steps: (1) ASA resin, chlorinated polyether and ASA masterbatch were fully mixed at room temperature, and then melt-extruded and granulated by a twin-screw extruder at a barrel temperature of 250°C and a screw speed of 200 rpm to obtain surface granular material for standby use; (2) The formulated amount of polyvinyl chloride resin, calcium carbonate modified by methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive, heat stabilizer, lubricant, coupling agent, modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin, carboxyl polyester resin, foaming agent, and PVC masterbatch are first fully mixed at room temperature, and then crushed to a particle size of 70-100 mesh by a high-speed grinder to prepare a core layer premix for standby use; (3) Take the surface layer granular material and the core layer premix according to the mass ratio, melt the core layer premix and the surface layer granular material through different twin-screw extruders, and then enter the core layer cavity and the surface layer cavity of the co-extrusion mold respectively. A glass fiber mesh cloth treated with methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive is fixed in advance in the middle 1 / 2 of the core layer cavity. The core layer melt fills the core layer cavity and is fully combined with the glass fiber mesh cloth to complete the foaming and surface layer co-extrusion molding. After cooling molding, surface layer surface embossing treatment, and fixed length cutting, a bending-resistant polyvinyl chloride foam co-extruded composite material is obtained; the conditions for the core layer extrusion molding are: barrel temperature of 200℃, screw speed of 10rpm; the conditions for the surface layer extrusion molding are: barrel temperature of 220℃, screw speed of 10rpm.

[0040] Example 2 A bending-resistant polyvinyl chloride foam co-extruded composite material, comprising a co-extruded surface layer and a core layer; the raw material mass ratio of the surface layer to the core layer is 0.6:10; a reinforcing layer formed by a glass fiber mesh cloth treated with a methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive is provided in the middle of the core layer; The raw materials for preparing the surface layer include the following components in parts by weight: ASA resin 80 parts, chlorinated polyether 20 parts, ASA masterbatch 0.8 parts; The raw materials for preparing the core layer include the following components in parts by weight: 70 parts of polyvinyl chloride resin, 23 parts of calcium carbonate modified with methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive, 5 parts of heat stabilizer (calcium stearate and zinc stearate in a mass ratio of 2:1), 0.4 parts of stearic acid as lubricant, 0.8 parts of silane coupling agent KH-540, 0.8 parts of azodicarbonamide as foaming agent, 12 parts of modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin, 4 parts of carboxyl polyester resin, and 0.3 parts of PVC masterbatch.

[0041] The preparation method is the same as that of Example 1.

[0042] Example 3 A bending-resistant polyvinyl chloride foam co-extruded composite material, comprising a co-extruded surface layer and a core layer; the raw material mass ratio of the surface layer to the core layer is 0.7:10; a reinforcing layer formed by a glass fiber mesh cloth treated with a methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive is provided in the middle of the core layer; The raw materials for preparing the surface layer include the following components in parts by weight: ASA resin 75 parts, chlorinated polyether 25 parts, ASA masterbatch 0.5 parts; The raw materials for preparing the core layer include the following components in parts by weight: 65 parts of polyvinyl chloride resin, 25 parts of calcium carbonate modified with methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive, 4 parts of heat stabilizer (calcium stearate and zinc stearate in a mass ratio of 2:1), 0.5 parts of lubricant hexadecanoic acid, 0.9 parts of silane coupling agent KH-540, 0.7 parts of foaming agent azodicarbonamide, 12 parts of modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin, 3 parts of carboxyl polyester resin, and 0.2 parts of PVC masterbatch.

[0043] The preparation method is the same as that of Example 1.

[0044] Example 4 A bending-resistant polyvinyl chloride foam co-extruded composite material, comprising a co-extruded surface layer and a core layer; the raw material mass ratio of the surface layer to the core layer is 0.55:10; the core layer is further provided with a reinforcement layer formed of a glass fiber mesh cloth treated with a methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive; The raw materials for preparing the surface layer include the following components in parts by weight: ASA resin 77 parts, chlorinated polyether 23 parts, ASA masterbatch 0.6 parts; The raw materials for preparing the core layer include the following components in parts by weight: 80 parts of polyvinyl chloride resin, 20 parts of calcium carbonate modified with methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive, 5 parts of heat stabilizer (calcium stearate and zinc stearate in a mass ratio of 2:1), 0.5 parts of hexadecanoic acid as lubricant, 1.0 parts of silane coupling agent JH-M902, 0.9 parts of azodicarbonamide as foaming agent, 10 parts of modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin, 4 parts of carboxyl polyester resin, and 0.1 parts of PVC masterbatch.

[0045] The preparation method is the same as that of Example 1.

[0046] Comparative Example 1 The other parts are the same as Example 1, except that the core layer does not use modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder, carboxyl polyester resin and glass fiber mesh cloth reinforcement layer, but only uses polyvinyl chloride resin and other auxiliary ingredients.

[0047] Comparative Example 2 Other aspects are the same as those of Example 1, except that the core layer does not use modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder.

[0048] Comparative Example 3 Other aspects are the same as in Example 1, except that there is no glass fiber mesh reinforcement layer in the core layer.

[0049] Comparative Example 4 Other aspects are the same as those of Example 1, except that the glass fiber mesh in the core layer is not treated with the methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive.

[0050] Comparative Example 5 Other aspects are the same as those of Example 1, except that the core layer uses ordinary heavy calcium carbonate with a particle size of 800 mesh, and the calcium carbonate used is not modified with the methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive.

[0051] Comparative Example 6 Other aspects are the same as in Example 1, except that the core layer does not use carboxyl polyester resin.

[0052] Comparative Example 7 The other parts are the same as those in Example 1, except that the surface layer does not use chlorinated polyether resin, but only uses ASA resin.

[0053] Performance testing: Long span bending strength and wear resistance are tested in accordance with GB / T 29418-2023. Bending strength is tested according to Section 5.3 (span length 400mm, three-point bending), and wear resistance is tested according to Section 5.13.1 (load weight: 1000g). The weathering performance test was conducted in accordance with GB / T 29365-2012. The exposure conditions adopted the parameters of Condition 1 in Section 6.2.2. The test was completed continuously for 10 cycles, totaling 120 hours.

[0054] The temperature difference resistance test is carried out according to the following method, that is, (40±2)℃, 3h→(-25±2)℃, 4h→(25±2)℃, 3h, 10h as one cycle. The above temperature difference cycle is performed continuously for 30 cycles, and then the appearance of cracks on the plate is observed.

[0055] The boiling water resistance test method is carried out in accordance with Section 4.52 of the GB / T-17657-2022 standard.

[0056] Table 1 Comparison of plate properties of the embodiment and the comparative examples

[0057] As shown in Table 1, the foamed polyvinyl chloride composite materials (Examples 1-4), prepared using a specific formulation and process, exhibit 400 mm long-span flexural strength exceeding 63 MPa, and surface abrasion resistance below 195 mg / 1000 r. In terms of weather resistance, after 10 cycles of weathering testing, neither the surface nor the core layer showed any changes. In particular, the surface layer showed no apparent changes when exposed to a xenon lamp, demonstrating excellent weather resistance. Regarding temperature differential resistance, after 30 cycles of repeated testing at different temperatures, no cracks were observed at the interfaces between the surface, core, and glass fiber cloth layers of the foamed polyvinyl chloride composite materials, demonstrating excellent bonding and adhesion. In terms of water resistance, even after boiling for 2 hours, neither the surface nor the core layer showed any changes.

[0058] Comparative Example 1 does not use the modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder, carboxyl polyester resin and glass fiber mesh cloth as the reinforcement layer prepared by the present invention, but only uses polyvinyl chloride resin and other auxiliary ingredients. This is basically an ordinary polyvinyl chloride core layer foam composite material product. After co-extrusion with the surface layer, the bending strength is significantly reduced. Under a span of 400mm, the bending strength can only reach 35.7Mpa, which is much lower than the bending strength of the product of the present invention and cannot be used in the long span field. Comparative Example 2 does not use modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder, and the carboxyl polyester resin cannot cure itself, resulting in no curable component in the core layer. Not only does the bending strength decrease significantly, the bending strength decreases to 46.9Mpa under a 400mm long span, and the core layer lacks the high-temperature curing effect of the modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder, and its interface bonding strength with the reinforcing layer glass fiber mesh cloth is also slightly reduced. Comparative Example 3 does not use The glass fiber mesh cloth with a reinforced layer results in a certain degree of decrease in bending strength, indicating that the glass fiber mesh cloth treated with an adhesive used in the present invention is co-cured with the core layer resin, which brings about an improvement in bending strength; the glass fiber mesh cloth used in comparative example 4 is not treated with an adhesive, resulting in a slight decrease in strength due to the lack of resin on the surface of the glass fiber cloth to participate in the curing and cross-linking of the core layer resin, and in terms of temperature difference resistance, the interface bonding strength between the core layer and the glass fiber mesh cloth also decreases slightly, resulting in the appearance of very slight cracks; comparative example 5 uses Ordinary heavy calcium carbonate is available on the market and is not pre-treated with an adhesive. Its compatibility with the core layer system is general, the bending strength decreases, and the core layer becomes very slightly loose after being boiled in water for 2 hours; Comparative Example 6 does not use the specific carboxyl polyester resin of the present invention for adjusting the curing toughness and mechanical properties, resulting in excessive rigidity and cohesion of the cured core layer, and the core layer may have defects such as very slight cracks after the temperature difference resistance test; Comparative Example 7 only uses ASA resin as the surface layer, resulting in a decrease in wear resistance, and the wear value reaches 256.8 mg / 1000r.

[0059] In summary, the product of the present invention has excellent wear resistance and high long-span bending strength, and is suitable for use in polyvinyl chloride composite materials that require outdoor weather resistance, wear resistance, and long spans.

[0060] The above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced with equivalents, without departing from the spirit and substance of the claims of the present invention; and such modifications or replacements remain within the scope of the claims of the present invention.

Claims

1. A bending-resistant polyvinyl chloride foam co-extruded composite material, characterized in that: The composite material comprises a co-extruded surface layer and a core layer; the raw material mass ratio of the surface layer to the core layer is 0.5-0.8:10; a reinforcement layer formed by continuous glass fiber mesh cloth is further provided in the middle of the core layer; The raw materials for preparing the surface layer include the following components in parts by weight: 70-80 parts of ASA resin, 20-30 parts of chlorinated polyether, and 0.3-0.8 parts of ASA masterbatch; The raw materials for preparing the core layer include the following components in parts by weight: 65-80 parts of polyvinyl chloride resin, 20-25 parts of modified calcium carbonate, 3-5 parts of heat stabilizer, 0.4-0.6 parts of lubricant, 0.8-1.0 parts of coupling agent, 0.7-1.1 parts of foaming agent, 10-13 parts of modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin, 3-4 parts of carboxyl polyester resin, and 0.1-0.3 parts of PVC masterbatch; The glass fiber mesh is a glass fiber mesh treated with methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive; The modified calcium carbonate is calcium carbonate modified by methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive.

2. The bending-resistant polyvinyl chloride foam co-extruded composite material according to claim 1, characterized in that: The methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive was prepared by the following method: (1) Add 37% formaldehyde aqueous solution and methanol into the reactor, start stirring and stir evenly, then use 10-15% sodium hydroxide aqueous solution to adjust the pH value of the system to 8.0-9.0, then add melamine and 1,3-bis(4'-aminophenoxy)benzene, and heat to 65-70°C for heat preservation polymerization reaction; the molar ratio of raw materials is melamine: 1,3-bis(4'-aminophenoxy)benzene: formaldehyde: methanol = 1: 0.3-0.4: 7.5-8.8: 2.5-3.0; (2) After the reaction system has no insoluble matter and becomes homogeneous, cool it to 40-50°C, add concentrated sulfuric acid to adjust the pH value to 3.0-4.0, and continue the polymerization reaction at this temperature; (3) Sampling and testing: when the viscosity of the system is 120-140 mPa.s, add 10-15% sodium hydroxide aqueous solution again to adjust the pH value of the system to 9.0-10.0, increase the temperature and perform reduced pressure distillation, with the vacuum degree controlled at -0.096 to -0.098 MPa and the distillation temperature at 90-95°C; (4) Sampling and testing the volatile content of the reactants in step (3). When the volatile content is 30-35%, a methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive is obtained.

3. The anti-bending polyvinyl chloride foam co-extruded composite material according to claim 1, characterized in that: The modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin was prepared by the following method: (1) Add 37% formaldehyde aqueous solution and methanol into the reactor, start stirring and stir evenly, then use 10-15% sodium hydroxide aqueous solution to adjust the pH value of the system to 8.0-9.0, then add melamine and 1,3-bis(4'-aminophenoxy)benzene, and heat to 65-70°C for heat preservation polymerization reaction; the molar ratio of raw materials is melamine: 1,3-bis(4'-aminophenoxy)benzene: formaldehyde: methanol = 1: 0.3-0.4: 7.5-8.8: 2.5-3.0; (2) After the reaction system has no insoluble matter and becomes homogeneous, cool it to 40-50°C, add concentrated sulfuric acid to adjust the pH value to 3.0-4.0, and continue the polymerization reaction at this temperature; (3) Sampling and testing: when the viscosity of the system is 120-140 mPa.s, add 10-15% sodium hydroxide aqueous solution again to adjust the pH value of the system to 9.0-10.0, increase the temperature and perform reduced pressure distillation, with the vacuum degree controlled at -0.096 to -0.098 MPa and the distillation temperature at 90-95°C; (4) Sampling and testing the volatile content of the reactants in step (3). When the volatile content is 7-10%, the vacuum system is released, and hexahydroxymethylmelamine powder is added. After stirring and mixing, the material is released and placed in a vacuum oven for drying. The oven temperature is 85-90°C and the vacuum degree is -0.098 to -0.099 MPa. When the volatile content is less than 2%, the material is taken out and crushed into 60-80 mesh powder to obtain modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin powder, wherein the molar amount of hexahydroxymethylmelamine is 0.1-0.12 times the molar amount of melamine.

4. The bending-resistant polyvinyl chloride foam co-extruded composite material according to claim 1, characterized in that: The heat stabilizer is a complex of calcium stearate and zinc stearate, with a mass ratio of 2:1-1.3; The lubricant is stearic acid or hexadecanoic acid; The coupling agent is silane coupling agent JH-M902 or silane coupling agent KH-540; The blowing agent is azodicarbonamide.

5. The bending-resistant polyvinyl chloride foam co-extruded composite material according to claim 1, characterized in that: The acid value of the carboxyl polyester resin is 25-29 mgKOH / g.

6. A method for preparing the bending-resistant polyvinyl chloride foam co-extruded composite material according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) ASA resin, chlorinated polyether and ASA masterbatch in the formula are fully mixed at room temperature, and then melt-extruded and granulated by a twin-screw extruder to obtain surface layer granules for standby use; (2) The formulated amount of polyvinyl chloride resin, calcium carbonate modified by methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive, heat stabilizer, lubricant, coupling agent, modified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin, carboxyl polyester resin, foaming agent, and PVC masterbatch are first fully mixed at room temperature, and then crushed to a particle size of 70-100 mesh by a high-speed grinder to prepare a core layer premix for standby use; (3) Take the surface layer granular material and the core layer premix according to the mass ratio, melt the core layer premix and the surface layer granular material through different twin-screw extruders, and then enter the core layer cavity and the surface layer cavity of the co-extrusion mold respectively. A glass fiber mesh cloth treated with methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive is fixed in advance in the middle 1 / 2 of the core layer cavity. The core layer melt fills the core layer cavity and is fully combined with the glass fiber mesh cloth to complete the foaming and surface layer co-extrusion molding. After cooling molding, surface layer surface embossing treatment, and fixed length cutting, a bending-resistant polyvinyl chloride foam co-extruded composite material is obtained.

7. The preparation method according to claim 6, characterized in that The preparation method of calcium carbonate modified by methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive comprises: An automatic sprayer is used to spray the methylated melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive diluted with water on the surface of calcium carbonate. The mass ratio of the adhesive to calcium carbonate is 3-5:

100. The calcium carbonate is continuously stirred during the spraying process to ensure uniform spraying. After the spraying is completed, it is fully mixed in a mixer for 10-15 minutes and then vacuum dried to obtain a modified calcium carbonate with a volatile matter of less than 1%.

8. The preparation method according to claim 6, characterized in that The preparation method of the glass fiber mesh cloth treated with a methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive comprises: Soak the glass fiber mesh in methyl etherified melamine-1,3-bis(4'-aminophenoxy)benzaldehyde resin adhesive for 20-30 seconds, hang it vertically at room temperature to dry until no liquid drops, hang it in an oven or drying room and use hot air for pre-curing treatment. The oven or drying room temperature is 80-85℃, the time is 10-15 minutes, and then cool to room temperature.

9. The preparation method according to claim 6, characterized in that In step (1), the barrel temperature of the twin-screw extruder is 240-250° C., and the screw speed is 150-200 rpm.

10. The preparation method according to claim 6, characterized in that In step (3), the conditions for extrusion molding of the core layer are: barrel temperature of 200-205°C, screw speed of 10-20 rpm; The conditions for the surface layer extrusion molding are: barrel temperature of 220-230°C and screw speed of 10-20 rpm.

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