Polyvinyl chloride alloy material and preparation method thereof

Abstract

The invention provides a polyvinyl chloride alloy material and a preparation method thereof. The polyvinyl chloride alloy material is prepared from the following raw materials in parts by weight: 30 to 65 parts of polyvinyl chloride resin, 5 to 15 parts of polyether type thermoplastic polyurethane elastomer, 20 to 50 parts of dioctyl terephthalate, 5 to 20 parts of surface modified nano calcium powder and 5 to 20 parts of phosphorus-nitrogen composite flame retardant. The polyvinyl chloride alloy material has relatively high elasticity, wear resistance and swing resistance, also has relatively good flame retardant property and tensile strength, and is applicable to materials for manufacturing high-resilience aircraft connectors and other products needing high elasticity and swing resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of polyvinyl chloride synthesis, and in particular to a polyvinyl chloride alloy material suitable for manufacturing high-rebound aircraft connector materials and other products requiring high elasticity and swing resistance, and a preparation method thereof. Background Art

[0002] Aircraft will experience various mechanical stresses and environmental changes during flight, so the industry has put forward strict requirements on the mechanical strength, elasticity and swing resistance of connector materials in aircraft. In the prior art, commonly used connector materials include silicone, nylon, PVC materials, etc. The mechanical strength of silicone materials is relatively low, and they are prone to fatigue after long-term use, so they are not suitable for use in areas with high intensity of use. Nylon materials are not easy to process, and the processing has strict requirements on the machine, and the cost of both is higher than that of PVC products. At present, most aircraft connector materials and other products that require high elasticity and swing resistance use PVC.

[0003] Although traditional PVC materials are low-cost and easy to process, the aircraft connectors made from them have the following problems in dynamic load scenarios: insufficient elasticity, permanent deformation ≥15% after high-frequency plugging and unplugging; poor swing resistance, cracks appear after 50,000 swings (customized standard). Therefore, in products such as the electrical field that require frequent plugging and unplugging or are used in a swinging environment, the elasticity and swing resistance of traditional PVC materials are limited, and they cannot provide sufficient stability and reliability in high-frequency vibration and swing environments.

[0004] In order to improve the elasticity and sway resistance of PVC materials, the industry has made improvements to PVC materials. For example, by selecting from PVC substrates, increasing the K value of PVC powder to improve mechanical properties, but the high K value of PVC powder will lead to difficulties in material processing and molding, especially for product structures with thicker glue positions, which are difficult to mold. There are also thermoplastic elastomers and plasticizers added to the traditional PVC substrate to improve elasticity and sway resistance, but the compatibility of PVC substrates, thermoplastic elastomers and plasticizers is poor. In addition, the mobility of plasticizers is high (≥12%), which causes PVC materials to lose their plasticizing effect during long-term use, and become hardened and brittle, thereby affecting their flexibility and durability. In addition, adding flame retardants to PVC materials can improve the flame retardant effect, but the use of flame retardants will reduce mechanical properties such as tensile strength. Therefore, how to balance the flame retardant properties and mechanical strength of PVC materials is also a major problem. Summary of the invention

[0005] Based on the above problems, the purpose of the present invention is to provide a polyvinyl chloride alloy material and a preparation method thereof. The polyvinyl chloride alloy material has high elasticity, wear resistance and swing resistance, and also has good flame retardancy and tensile strength, and can be used to manufacture materials for high-rebound aircraft connectors and other products requiring high elasticity and swing resistance.

[0006] To achieve the above-mentioned purpose, the present invention provides a polyvinyl chloride alloy material on the one hand. The raw materials for preparation include, by weight, 30 to 65 parts of polyvinyl chloride resin, 5 to 15 parts of polyether thermoplastic polyurethane elastomer, 20 to 50 parts of dioctyl terephthalate, 5 to 20 parts of surface-modified nano-calcium powder and 5 to 20 parts of phosphorus-nitrogen composite flame retardant.

[0007] The polyvinyl chloride alloy material of the present invention has at least the following technical effects.

[0008] (1) Dioctyl terephthalate is used as a plasticizer. In addition to its plasticizing effect, it can also reduce the resistance of PVC chain segment movement. The polyether thermoplastic polyurethane elastomer provides elastic recovery force. Therefore, the balance between the hardness and resilience of the polyvinyl chloride alloy material can be achieved through the action of the polyether thermoplastic polyurethane elastomer and dioctyl terephthalate.

[0009] (2) Surface-modified nano-calcium powder, as a small particle material, can fill the pores of the matrix in the polyvinyl chloride alloy material and improve the density, thereby weakening the effect of adding flame retardants on the decrease in mechanical properties such as tensile strength of the polyvinyl chloride alloy material. In addition, phosphorus-nitrogen composite flame retardant is a halogen-free flame retardant that decomposes when heated to form an expanded carbon layer, while surface-modified nano-calcium powder catalyzes the formation of carbon. Therefore, the synergistic flame retardancy of surface-modified nano-calcium powder and phosphorus-nitrogen composite flame retardant can greatly improve the flame retardancy of polyvinyl chloride alloy materials.

[0010] (3) The ether bonds contained in polyether thermoplastic polyurethane elastomers can construct a dynamic hydrogen bond network structure. In addition to enhancing the elasticity of polyvinyl chloride alloy materials, the formed dynamic hydrogen bond network structure can also inhibit the mobility of dioctyl terephthalate, thereby improving the flexibility and durability of polyvinyl chloride alloy materials.

[0011] As a technical solution of the present invention, the K value of the polyvinyl chloride resin is 57-70.

[0012] As a technical solution of the present invention, the weight average molecular weight of the polyether thermoplastic polyurethane elastomer is 50,000-200,000, and the ether bond content is ≥40 mol%.

[0013] As a technical solution of the present invention, the surface of the surface-modified nano-calcium powder can be modified by stearic acid.

[0014] As a technical solution of the present invention, the particle size of the surface modified nano calcium powder is ≤100 nm.

[0015] As a technical solution of the present invention, the phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate, and the weight ratio of the ammonium polyphosphate to the melamine cyanurate is 1.8-2.5:1.

[0016] As a technical solution of the present invention, the weight ratio of the polyether thermoplastic polyurethane elastomer to dioctyl terephthalate is 1:3.5~5.0.

[0017] As a technical solution of the present invention, the weight ratio of the nano calcium powder to the phosphorus-nitrogen composite flame retardant is 1:1.5~2.0.

[0018] A second aspect of the present invention provides a method for preparing a polyvinyl chloride alloy material, comprising: (1) Premix The polyvinyl chloride resin and the dioctyl terephthalate are mixed to form a pre-plasticized matrix; (2) Blending Then, the polyether thermoplastic polyurethane elastomer, the surface-modified nano calcium powder and the phosphorus-nitrogen composite flame retardant are added in sequence, and stirred at a certain heating temperature for a certain time.

[0019] In this preparation method, polyvinyl chloride resin and dioctyl terephthalate are first mixed to form a pre-plasticized matrix, and then polyether thermoplastic polyurethane elastomer, surface modified nano calcium powder and phosphorus-nitrogen composite flame retardant are added to improve the compatibility of the components.

[0020] As a technical solution of the present invention, the premixing and the blending are carried out in a high-speed mixer, the premixing speed is 400~850rpm, the premixing time is 5~20min, the premixing temperature is 90~120°C, the blending speed is 950~1100rpm, the blending time is 6~15min, and the blending temperature is 120~150°C. DETAILED DESCRIPTION

[0021] The polyvinyl chloride alloy material of the present invention has a flame retardant property of UL94 up to V0, a ​​plasticizer migration rate of ≤5%, a hardness A of up to 90, an elastic recovery rate of ≥93%, a swing life of ≥100,000 times, and a tensile strength of >15MPa, so it can be used to manufacture materials for high-rebound aircraft connectors and other products that require high elasticity and swing resistance.

[0022] The raw materials for preparing the polyvinyl chloride alloy material of the invention include polyvinyl chloride resin, polyether thermoplastic polyurethane elastomer, dioctyl terephthalate, surface modified nano calcium powder and phosphorus-nitrogen composite flame retardant.

[0023] The weight percentage of the polyvinyl chloride resin is 30 to 65 parts, and as an example, it can be but not limited to 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, and 65 parts. The K value of the polyvinyl chloride resin is 57 to 70, and as an example, the K value can be but not limited to 57, 60, 63, 65, 68, and 70. The polyvinyl chloride resin is used as the base material of the polyvinyl chloride alloy material. Selecting a polyvinyl chloride resin with a certain K value, that is, selecting a PVC with a certain degree of polymerization, can adjust its strength.

[0024] The weight proportion of the polyether thermoplastic polyurethane elastomer is 5 to 15 parts, for example, it can be but not limited to 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts. The weight average molecular weight of the polyether thermoplastic polyurethane elastomer is 50000 to 200000, for example, the weight average molecular weight can be but not limited to 50000, 70000, 90000, 100000, 120000, 140000, 160000, 180000, 200000. The ether bond content is ≥40 mol%, for example, ≥45 mol%, or ≥50 mol%, or ≥55 mol%.

[0025] The weight proportion of dioctyl terephthalate is 20 to 50 parts, and as an example, it can be, but not limited to, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, and 50 parts. The weight ratio of polyether thermoplastic polyurethane elastomer to dioctyl terephthalate is 1:3.5 to 5.0, and as an example, the weight ratio can be, but not limited to, 1:3.5, 1:4.0, 1:4.5, and 1:5.0. The polyether thermoplastic polyurethane elastomer and dioctyl terephthalate are controlled to a certain weight ratio, which can not only give play to the elastic restoring force of the polyether thermoplastic polyurethane elastomer, but also better control the mobility of dioctyl terephthalate.

[0026] The weight proportion of the surface modified nano calcium powder is 5 to 20 parts, and as an example, it can be but not limited to 5 parts, 7 parts, 9 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, and 20 parts. The surface modified nano calcium powder can be modified by stearic acid on the surface of the nano calcium powder. The modification of the nano calcium powder by stearic acid can improve its surface lipophilicity so that it can be filled into the pores of the polyvinyl chloride alloy material matrix. The large specific surface area of ​​the nano calcium powder also helps the binding reliability between the calcium powder and the polyvinyl chloride to achieve a reinforcing effect. The surface modification of the nano calcium powder by stearic acid can be carried out in a conventional manner, such as first making a slurry of calcium powder and water, adding stearic acid at a heating temperature of 40 to 80°C and mixing for a certain period of time, filtering the filter cake, washing, and drying to obtain the surface modified nano calcium powder. The particle size of the surface-modified nano-calcium powder is ≤100 nm. As an example, the particle size may be, but is not limited to, ≤100 nm, ≤95 nm, ≤90 nm, ≤85 nm, or ≤80 nm.

[0027] The weight proportion of the phosphorus-nitrogen composite flame retardant is 5 to 20 parts, and as an example, it can be, but not limited to, 5 parts, 7 parts, 9 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, and 20 parts. The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate, and the weight ratio of ammonium polyphosphate to melamine cyanurate is 1.8 to 2.5:1. As an example, the weight ratio can be, but not limited to, 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, and 2.5:1. The weight ratio of nano calcium powder to the phosphorus-nitrogen composite flame retardant is 1:1.5 to 2.0. As an example, the weight ratio of the two can be, but not limited to, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, and 1:2.0. The nano calcium powder and phosphorus-nitrogen composite flame retardant are controlled at a certain weight ratio, so that the synergistic flame retardant effect of the two can be maximized.

[0028] In addition, the method for preparing the polyvinyl chloride alloy material of the present invention may include the following steps.

[0029] (1) Premix The polyvinyl chloride resin and dioctyl terephthalate are mixed to form a pre-plasticized matrix.

[0030] (2) Blending Then, polyether thermoplastic polyurethane elastomer, surface modified nano calcium powder and phosphorus-nitrogen composite flame retardant are added in sequence, and stirred at a certain heating temperature for a certain time.

[0031] Further premixing and blending are carried out in a high-speed mixer. And the speed of premixing is 400~850rpm, the time is 5~20min, and the temperature is 90~120°C. As an example, the speed can be but not limited to 400rpm, 450rpm, 500rpm, 550rpm, 600rpm, 650rpm, 700rpm, 750rpm, 800rpm, 850rpm. The time can be but not limited to 5min, 7min, 9min, 10min, 12min, 14min, 16min, 18min, 20min. The temperature can be but not limited to 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C. And the speed of blending is 950~1100rpm, the time is 6~15min, and the temperature is 120~150°C. As an example, the speed may be, but is not limited to, 950 rpm, 1000 rpm, 1050 rpm, 1100 rpm. The time may be, but is not limited to, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min. The temperature may be, but is not limited to, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C. Blend until the torque fluctuation of the high-speed mixer is ≤5%, stop mixing, and the components are fully dispersed. The blending temperature is low, and plasticization at low temperature can inhibit the migration of the plasticizer.

[0032] In order to better illustrate the purpose, technical scheme and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of the present invention and should not be used as a limitation of the present invention.

[0033] Example 1 This embodiment is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 50 parts of polyvinyl chloride resin (K value is 65), 10 parts of polyether thermoplastic polyurethane elastomer (weight average molecular weight is 100000, ether bond content is 42 mol%), 35 parts of dioctyl terephthalate, 10 parts of surface modified nano calcium powder (particle size is 90 nm) and 15 parts of phosphorus-nitrogen composite flame retardant.

[0034] The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate in a weight ratio of 2:1. The preparation of surface-modified nano-calcium powder includes: firstly preparing a slurry with a solid content of 50% by mixing nano-calcium powder and water into a water bath, adding stearic acid (accounting for 10% of the weight of the nano-calcium powder) at a heating temperature of 75°C and mixing for 0.5h, filtering and washing the filter cake, and drying to obtain stearic acid surface-modified nano-calcium powder.

[0035] Example 2 This embodiment is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 65 parts of polyvinyl chloride resin (K value is 60), 8 parts of polyether thermoplastic polyurethane elastomer (weight average molecular weight is 200000, ether bond content is 45 mol%), 35 parts of dioctyl terephthalate, 12 parts of surface modified nano calcium powder (particle size is 95 nm) and 20 parts of phosphorus-nitrogen composite flame retardant.

[0036] The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate in a weight ratio of 2.5:1. The preparation of surface-modified nano-calcium powder includes: firstly preparing a slurry with a solid content of 40% by mixing nano-calcium powder and water into a water bath, adding stearic acid (accounting for 8% of the weight of the nano-calcium powder) at a heating temperature of 85°C and mixing for 1.0h, filtering and washing the filter cake, and drying to obtain stearic acid surface-modified nano-calcium powder.

[0037] Example 3 This embodiment is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 45 parts of polyvinyl chloride resin (K value is 70), 15 parts of polyether thermoplastic polyurethane elastomer (weight average molecular weight is 150000, ether bond content is 42 mol%), 50 parts of dioctyl terephthalate, 8 parts of surface modified nano calcium powder (particle size is 90 nm) and 12 parts of phosphorus-nitrogen composite flame retardant.

[0038] The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate in a weight ratio of 2:1. The preparation of surface-modified nano-calcium powder includes: firstly preparing a slurry with a solid content of 50% by nano-calcium powder and water and placing it in a water bath, adding stearic acid (accounting for 15% of the weight of the nano-calcium powder) at a heating temperature of 75°C and mixing for 0.5h, filtering and washing the filter cake, and drying to obtain stearic acid surface-modified nano-calcium powder.

[0039] Example 4 This embodiment is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 50 parts of polyvinyl chloride resin (K value is 65), 10 parts of polyether thermoplastic polyurethane elastomer (weight average molecular weight is 100000, ether bond content is 42 mol%), 35 parts of dioctyl terephthalate, 10 parts of surface modified nano calcium powder (particle size is 90 nm) and 15 parts of phosphorus-nitrogen composite flame retardant.

[0040] The phosphorus-nitrogen composite flame retardant includes bisphenol A bis(diphenyl phosphate) and melamine cyanurate in a weight ratio of 2:1. The preparation of surface-modified nano-calcium powder includes: firstly preparing a slurry with a solid content of 50% by mixing nano-calcium powder and water into a water bath, adding stearic acid (accounting for 10% of the weight of nano-calcium powder) at a heating temperature of 75°C and mixing for 0.5h, filtering and washing the filter cake, and drying to obtain stearic acid surface-modified nano-calcium powder.

[0041] Example 5 This embodiment is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 50 parts of polyvinyl chloride resin (K value is 65), 10 parts of polyether thermoplastic polyurethane elastomer (weight average molecular weight is 100000, ether bond content is 42 mol%), 20 parts of dioctyl terephthalate, 10 parts of surface modified nano calcium powder (particle size is 90 nm) and 15 parts of phosphorus-nitrogen composite flame retardant.

[0042] The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate in a weight ratio of 2:1. The preparation of surface-modified nano-calcium powder includes: firstly preparing a slurry with a solid content of 50% by mixing nano-calcium powder and water into a water bath, adding stearic acid (accounting for 10% of the weight of the nano-calcium powder) at a heating temperature of 75°C and mixing for 0.5h, filtering and washing the filter cake, and drying to obtain stearic acid surface-modified nano-calcium powder.

[0043] Example 6 This embodiment is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 50 parts of polyvinyl chloride resin (K value is 65), 8 parts of polyether thermoplastic polyurethane elastomer (weight average molecular weight is 100000, ether bond content is 42 mol%), 50 parts of dioctyl terephthalate, 10 parts of surface modified nano calcium powder (particle size is 90 nm) and 15 parts of phosphorus-nitrogen composite flame retardant.

[0044] The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate in a weight ratio of 2:1. The preparation of surface-modified nano-calcium powder includes: firstly preparing a slurry with a solid content of 50% by mixing nano-calcium powder and water into a water bath, adding stearic acid (accounting for 10% of the weight of the nano-calcium powder) at a heating temperature of 75°C and mixing for 0.5h, filtering and washing the filter cake, and drying to obtain stearic acid surface-modified nano-calcium powder.

[0045] Example 7 This embodiment is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 50 parts of polyvinyl chloride resin (K value is 65), 10 parts of polyether thermoplastic polyurethane elastomer (weight average molecular weight is 100000, ether bond content is 42 mol%), 35 parts of dioctyl terephthalate, 10 parts of surface modified nano calcium powder (particle size is 90 nm) and 10 parts of phosphorus-nitrogen composite flame retardant.

[0046] The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate in a weight ratio of 2:1. The preparation of surface-modified nano-calcium powder includes: firstly preparing a slurry with a solid content of 50% by mixing nano-calcium powder and water into a water bath, adding stearic acid (accounting for 10% of the weight of the nano-calcium powder) at a heating temperature of 75°C and mixing for 0.5h, filtering and washing the filter cake, and drying to obtain stearic acid surface-modified nano-calcium powder.

[0047] Example 8 This embodiment is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 50 parts of polyvinyl chloride resin (K value is 65), 10 parts of polyether thermoplastic polyurethane elastomer (weight average molecular weight is 100000, ether bond content is 42 mol%), 35 parts of dioctyl terephthalate, 8 parts of surface modified nano calcium powder (particle size is 90 nm) and 20 parts of phosphorus-nitrogen composite flame retardant.

[0048] The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate in a weight ratio of 2:1. The preparation of surface-modified nano-calcium powder includes: firstly preparing a slurry with a solid content of 50% by mixing nano-calcium powder and water into a water bath, adding stearic acid (accounting for 10% of the weight of the nano-calcium powder) at a heating temperature of 75°C and mixing for 0.5h, filtering and washing the filter cake, and drying to obtain stearic acid surface-modified nano-calcium powder.

[0049] Comparative Example 1 This comparative example is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 50 parts of polyvinyl chloride resin (K value is 65), 10 parts of polyether thermoplastic polyurethane elastomer (weight average molecular weight is 100000, ether bond content is 42 mol%), 35 parts of dioctyl terephthalate, 10 parts of nano calcium powder (particle size is 90 nm) and 15 parts of phosphorus-nitrogen composite flame retardant.

[0050] The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate in a weight ratio of 2:1.

[0051] Comparative Example 2 This comparative example is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 50 parts of polyvinyl chloride resin (K value is 65), 35 parts of dioctyl terephthalate, 10 parts of surface modified nano calcium powder (particle size is 90nm) and 15 parts of phosphorus-nitrogen composite flame retardant.

[0052] The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate in a weight ratio of 2:1. The preparation of surface-modified nano-calcium powder includes: firstly preparing a slurry with a solid content of 50% by mixing nano-calcium powder and water into a water bath, adding stearic acid (accounting for 10% of the weight of the nano-calcium powder) at a heating temperature of 75°C and mixing for 0.5h, filtering and washing the filter cake, and drying to obtain stearic acid surface-modified nano-calcium powder.

[0053] Comparative Example 3 This comparative example is a polyvinyl chloride alloy material. In terms of weight, the raw materials for preparing the polyvinyl chloride alloy material include 50 parts of polyvinyl chloride resin (K value is 65), 10 parts of polyether thermoplastic polyurethane elastomer (weight average molecular weight is 100000, ether bond content is 42 mol%), 35 parts of dioctyl terephthalate and 15 parts of phosphorus-nitrogen composite flame retardant.

[0054] The phosphorus-nitrogen composite flame retardant includes ammonium polyphosphate and melamine cyanurate in a weight ratio of 2:1.

[0055] The preparation method of the polyvinyl chloride alloy material in Examples 1 to 8 and Comparative Examples 1 to 3 may include the following steps: If there is no corresponding substance in the comparative example, it is not added.

[0056] (1) Premix The polyvinyl chloride resin and dioctyl terephthalate were mixed in a high-speed mixer to form a pre-plasticized matrix, and the mixing speed was 600 rpm, the time was 15 minutes, and the temperature was 110°C.

[0057] (2) Blending Add polyether thermoplastic polyurethane elastomer, surface modified nano calcium powder and phosphorus-nitrogen composite flame retardant to the high-speed mixer in sequence, increase the speed to 1000 rpm, and stir at 130° C. for 10 min until the torque fluctuation is ≤5% to fully disperse the components, and stop mixing.

[0058] The polyvinyl chloride alloy materials of Examples 1 to 8 and Comparative Examples 1 to 3 were molded at 185° C. to obtain products. The products were tested for performance. The results are shown in Table 1. The test method is as follows.

[0059] Shore hardness test: Test hardness according to the standard "ASTM D2240-2015 Standard Test Method for Durometer Hardness".

[0060] Tensile strength / elongation at break test: Refer to the national standard "GB / T 1040.3-2006 Determination of tensile properties of plastics Part 3: Test conditions for thin plastics and sheets" to test the tensile strength before aging and the elongation at break before aging.

[0061] Flame retardant test: Flame retardant grades are classified according to UL94.

[0062] Plasticizer migration test: Plasticizer migration is tested according to the standard "BS EN ISO 177-2017 Plastics. Determination of plasticizer diffusion".

[0063] Swing test: Fasten the connector made of polyvinyl chloride alloy material vertically upward on the test fixture, hang a 1KG weight from the connector sheath to 300mm from the wire body, 30 times / min, load 1.5A, test angle 180° left and 180° right as one time. Follow the above method for a certain number of cycles to observe whether the connector breaks, record the number of times it breaks and stop the swing test.

[0064] Table 1 Properties of polyvinyl chloride alloy materials of Examples 1 to 8 and Comparative Examples 1 to 3

[0065] From the results in Table 1, it can be seen that the use of polyvinyl chloride resin, dioctyl terephthalate and phosphorus-nitrogen composite flame retardant as the raw materials of polyvinyl chloride alloy materials, combined with polyether thermoplastic polyurethane elastomer, can achieve a balance between the hardness and resilience of the polyvinyl chloride alloy material, and can also inhibit the migration rate of dioctyl terephthalate. Combined with surface modified nano-calcium powder, the flame retardant properties can be improved while the mechanical properties can be improved.

[0066] Combining Example 1 with Example 4, it can be seen that when the phosphorus-nitrogen composite flame retardant is a combination of ammonium polyphosphate and melamine cyanurate, the flame retardant performance of the material is better. Combining Example 1 with Examples 5-6, it can be seen that when the weight ratio of polyether thermoplastic polyurethane elastomer and dioctyl terephthalate is controlled within a certain range, the swing and resilience of the polyvinyl chloride alloy material are better, and the mobility of dioctyl terephthalate is lower. Combining Example 1 with Examples 7-8, it can be seen that when the weight ratio of nano calcium powder and phosphorus-nitrogen composite flame retardant is controlled within a certain range, the polyvinyl chloride alloy material not only has better flame retardant performance but also has higher strength.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A polyvinyl chloride alloy material, characterized in that: The raw materials include 30-65 parts of polyvinyl chloride resin, 5-15 parts of polyether thermoplastic polyurethane elastomer, 20-50 parts of dioctyl terephthalate, 5-20 parts of surface modified nano calcium powder and 5-20 parts of phosphorus-nitrogen composite flame retardant in parts by weight.

2. The polyvinyl chloride alloy material according to claim 1, characterized in that: The K value of the polyvinyl chloride resin is 57-70.

3. The polyvinyl chloride alloy material according to claim 1, characterized in that: The weight average molecular weight of the polyether thermoplastic polyurethane elastomer is 50,000-200,000, and the ether bond content is ≥40 mol%.

4. The polyvinyl chloride alloy material according to claim 1, characterized in that: The surface-modified nano-calcium powder can be prepared by modifying the surface of the nano-calcium powder using stearic acid.

5. The polyvinyl chloride alloy material according to claim 1, characterized in that: The particle size of the surface modified nano calcium powder is ≤100nm.

6. The polyvinyl chloride alloy material according to claim 1, characterized in that: The phosphorus-nitrogen composite flame retardant comprises ammonium polyphosphate and melamine cyanurate, and the weight ratio of the ammonium polyphosphate to the melamine cyanurate is 1.8-2.5:

1.

7. The polyvinyl chloride alloy material according to claim 1, characterized in that: The weight ratio of the polyether thermoplastic polyurethane elastomer to dioctyl terephthalate is 1:3.5-5.

0.

8. The polyvinyl chloride alloy material according to claim 1, characterized in that: The weight ratio of the nano calcium powder to the phosphorus-nitrogen composite flame retardant is 1:1.5-2.

0.

9. The method for preparing a polyvinyl chloride alloy material according to any one of claims 1 to 8, characterized in that: include: (1) Premix The polyvinyl chloride resin and the dioctyl terephthalate are mixed to form a pre-plasticized matrix; (2) Blending Then, the polyether thermoplastic polyurethane elastomer, the surface-modified nano calcium powder and the phosphorus-nitrogen composite flame retardant are added in sequence, and stirred at a certain heating temperature for a certain time.

10. The method for preparing a polyvinyl chloride alloy material according to claim 9, characterized in that: The premixing and the blending are carried out in a high-speed mixer, the premixing speed is 400-850 rpm, the premixing time is 5-20 min, the premixing temperature is 90-120° C., the blending speed is 950-1100 rpm, the blending time is 6-15 min, and the blending temperature is 120-150° C.

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