High cold-resistant PVC composite material, preparation method and application thereof

Abstract

The application discloses a kind of high cold-resistant PVC composite material and preparation method and application thereof, belong to PVC cold-resistant material technical field.The high cold-resistant PVC composite material is by weight fraction, including:100 portions of PVC resin, 5-90 portions of aconitic acid monoester, 1-10 portions of cold-resistant modifier, 0.5-10 portions of lubricant, 3-20 portions of stabilizer, the T g It is not more than 50 DEG C;R in the aconitic acid monoester is alkyl with carbon atom number not more than 5.The high cold-resistant PVC composite material uses aconitic acid monoester with alkyl substituent group with carbon atom number not more than 5 as plasticizer, effectively improves its compatibility with PVC, and makes the composite material have excellent toughness, stability, tensile property and lower glass transition temperature (T g ), endows composite material with excellent cold resistance.

Description

Technical Field

[0001] This application relates to a high cold-resistant PVC composite material, its preparation method and application, belonging to the technical field of PVC cold-resistant materials. Background Technology

[0002] PVC is a high-performance, widely used general-purpose plastic, but its plasticity is relatively poor, requiring the addition of plasticizers for modification. Currently, there are two main types of plasticizing modification for PVC: external plasticizing and internal plasticizing. External plasticizing refers to adding plasticizers to PVC through physical blending, while internal plasticizing involves grafting plasticizers onto the PVC molecular chain via a chemical reaction. Both methods require good compatibility between the plasticizer and PVC to improve PVC performance or enhance certain properties.

[0003] Plasticizers primarily increase the plasticity of polymers by weakening the van der Waals forces between polymer molecules, thereby increasing the mobility of polymer chains and reducing crystallinity. Phthalate plasticizers, such as dioctyl phthalate (DOP) and diisodecyl phthalate (DIDP), are traditional plasticizers. Their disadvantages include poor compatibility with PVC, poor cold resistance, and migration to the surface of plastic products after prolonged use, leading to a decline in the performance of plastic products. Furthermore, phthalate plasticizers pose hazards to the environment and human health.

[0004] Chinese patent CN102046694A discloses a bio-derived plasticizer for biopolymers, wherein the polyester plasticizing unit is formed from monomers containing polyfunctional alcohols and aliphatic anhydrides or their equivalents, dicarboxylic acids and ester derivatives. It can improve the flexibility of biopolymers without adversely affecting their modulus, but its glass transition temperature is high, resulting in poor cold resistance and stability.

[0005] Currently, some plasticizers have poor compatibility with PVC, which can lead to a decrease in the plasticity and flexibility of PVC, making it easier for plasticizers to leach out of PVC. Therefore, finding a highly compatible plasticizer is an important development direction for plasticizers today. However, some plasticizers with good compatibility are difficult to improve the cold resistance of PVC materials while improving their plasticity. Summary of the Invention

[0006] To address the aforementioned issues, a high-cold-resistant PVC composite material is provided. This composite material uses aconitic acid monoester with alkyl substituents having no more than 5 carbon atoms as a plasticizer, effectively improving its compatibility with PVC. Even with a large amount of plasticizer added, phase separation is not easily observed. Furthermore, this results in a composite material with excellent toughness, stability, tensile strength, and a low glass transition temperature (T0). g This gives the composite material excellent cold resistance.

[0007] According to one aspect of this application, a high cold-resistant PVC composite material is provided, comprising, by weight: 100 parts PVC resin, 5-90 parts aconitic acid monoester, 1-10 parts cold-resistant modifier, 0.5-10 parts lubricant, and 3-20 parts stabilizer, wherein the high cold-resistant PVC composite material has a T g No higher than 50℃;

[0008] The structural formula of the aconitic acid monoester is as follows:

[0009]

[0010] Where R is an alkyl group with no more than 5 carbon atoms.

[0011] Aconitic acid monoester is used, where each R substituent in its molecular structure is identical. These identical substituents ensure uniform compatibility and dispersibility of the aconitic ester in different systems, and this uniform distribution allows the composite material to maintain long-term stability. At lower temperatures, if the R substituents have different molecular structures, they will exhibit a more uneven distribution at lower free volumes, leading to poorer localized low-temperature performance of the material.

[0012] Preferably, the T of the high cold-resistant PVC composite material g No higher than 30℃.

[0013] Furthermore, when R is an alkyl group with no more than 5 carbon atoms, its double bond structure, similar to that of a benzene ring, provides strong rigidity when added to the PVC material system as a plasticizer. Simultaneously, the three ester groups on the molecule, working in conjunction with the rigid matrix, enable the plasticizer to provide significant support between the PVC molecular chains. This strong supporting effect significantly increases the free volume of the PVC material, requiring it to shrink to the free volume required for glass transition at even lower temperatures. Therefore, the glass transition temperature is significantly reduced, improving the low-temperature performance of the PVC composite. Additionally, the inventors discovered that alkyl groups with no more than 5 carbon atoms form short-chain esters, which possess strong polarity, further enhancing compatibility with PVC molecular chains and cold-resistant modifiers. Good compatibility is a prerequisite for the supporting effect of aconitate ester structures. Only when aconitate ester molecules can enter the molecular chains of PVC and the cold-resistant modifiers can their supporting effect be realized. Therefore, good compatibility and excellent low-temperature performance are the result of the synergistic effect of the short-chain ester of aconitate and the rigid matrix structure; neither is dispensable. The aconitine monoester used in this application is a short-chain aconitine ester. Due to its good compatibility, it effectively increases the limit of plasticizer dosage, enabling the composite material to achieve higher plasticity. On the one hand, it can effectively reduce the processing difficulty of the material, and on the other hand, it expands the application field and scope of the material.

[0014] Optionally, the aconitine monoester has an acid value of <0.15 mg KOH / g, a water content of <0.2%, and a purity of >97%.

[0015] Optionally, the aconitine monoester has a solubility of 50 parts or more in 100 parts of PVC resin, the aconitine monoester is liquid at 25°C, and the aconitine monoester is colorless and transparent or pale yellow at 25°C.

[0016] Preferably, the purity of the aconitine monoester is not less than 99%, and the color is not higher than 50 Pt-Co.

[0017] The acid value of aconitic acid monoester ensures that a large amount of acidic substances will not corrode and age the material during processing, affecting its basic properties and internal structure. This stabilizes and improves compatibility and the cold resistance of the composite material. The low moisture content prevents insufficient effective components during processing, thus avoiding situations where the material fails to achieve the expected plasticizing effect at the required addition amount. Higher purity of aconitic acid monoester indicates lower impurity content. Excessive impurities result in a smaller actual addition amount of aconitic acid monoester and less contact with PVC resin, reducing its compatibility with PVC and increasing the TT of the composite material. g This reduces cold resistance. Therefore, the purity of the aforementioned aconitic acid monoester can further improve the compatibility, plasticizing effect, and cold resistance of the composite material in PVC. Furthermore, a color intensity of no more than 50 Pt-Co can reduce the influence of plasticizers on the coloring of PVC materials, thereby improving the controllability of the composite material's appearance.

[0018] Optionally, the PVC resin has a degree of polymerization of 650-1800, a polydispersity index of 3-5, and a K value of 55-77.

[0019] Preferably, the polydispersity index of the PVC resin is 3.5-4.5.

[0020] When using PVC resin with the above degree of polymerization, the resulting PVC material has better toughness. This is because the macromolecular chains are intertwined and react with aconitine monoester, lubricant and stabilizer components to form a stable cross-linked network structure, thus having better toughness, plasticity, tensile strength and cold resistance.

[0021] The inventors discovered that the composite material exhibits optimal toughness and plasticity when the polydispersity index of the PVC resin used is 3-5. This is likely because when the polydispersity index of the PVC resin is 3-5, the material contains multiple PVC resins with different molecular weights. The mixing of resins with different molecular weights can better increase the free volume within the PVC, effectively increasing the solubility of aconitate plasticizer and enabling effective binding. This increases the interaction force between the plasticizer and the molecular chains, resulting in a PVC material with high toughness, high stability, and plasticity, as well as good stability and resistance to phase separation.

[0022] Optionally, the cold-resistant modifier is at least one of chlorinated polyethylene (CPE) and ethylene-vinyl acetate copolymer (EVA);

[0023] Preferably, the chlorine content in the chlorinated polyethylene is not less than 25%, and the VA content in the ethylene-vinyl acetate copolymer is 5-40%.

[0024] The inventors discovered that the cold-resistant modifier itself has a low T0. g Such as CPE's T g At around -25℃, EVA's T g At around -34℃, the chlorine content in chlorinated polyethylene must be no less than 25%, and the VA content in ethylene-vinyl acetate copolymer must be 5-40%. Only by adding these substances as cold-resistant modifiers to the composite material can the cold resistance of PVC be effectively improved. However, the compatibility between the aforementioned cold-resistant modifiers and PVC is generally poor. The aconitine monoester used in this application, however, has a strong solvent effect, effectively compatibility between the cold-resistant modifier and PVC, promoting uniform mixing of the three. Besides plasticizing PVC, the aconitine monoester also compatibilizes the cold-resistant modifier. Therefore, aconitine ester and the cold-resistant modifier have a synergistic effect, further improving the low-temperature performance of the PVC composite material.

[0025] Optionally, the lubricant is 2-4 parts;

[0026] The lubricant is at least one of oxidized polyethylene wax, glyceryl stearate, ethylene bis-stearamide synthetic wax, paraffin wax, and polyethylene wax, preferably ethylene bis-stearamide synthetic wax.

[0027] The aforementioned lubricant can lubricate PVC resin and aconitic acid monoester, helping aconitic acid monoester to quickly contact PVC resin and further improving the dispersion rate of aconitic acid monoester. Furthermore, the addition of this lubricant can lubricate the molecular chains of PVC resin, thereby increasing the mobility of the molecular chains and promoting the reduction of the To of the composite material by aconitic acid ester. g This improves the cold resistance of composite materials.

[0028] Optionally, the stabilizer is 4-7 parts;

[0029] The stabilizer is at least one of a heat stabilizer and a light stabilizer;

[0030] Preferably, the weight ratio of the heat stabilizer to the light stabilizer is 2-10:0.5-4, and more preferably 3-5:1-2.

[0031] The combination of the aforementioned light stabilizers and heat stabilizers can enhance the light and heat stability of the composite material, thereby improving its light and heat resistance and broadening its service temperature range.

[0032] Optionally, the heat stabilizer is selected from calcium stearate and zinc stearate in a weight ratio of 0.1-5:1.

[0033] When calcium stearate and zinc stearate are used as heat stabilizers in the above weight ratio, they can work synergistically with light stabilizers to further inhibit the deterioration of PVC resin and enhance the plasticizing effect. This is because calcium stearate and zinc stearate are easily dispersed and highly compatible in systems containing short-chain aconitic acid monoesters. When used in combination, they can be effectively dispersed in the system without excessive migration. Combined with this specific structure of aconitic acid monoester, the resulting PVC composite material possesses low hardness, high toughness, cold resistance, and plasticity.

[0034] Optionally, the light stabilizer is at least one of benzophenones, benzotriazoles, or triazines;

[0035] The benzophenones include at least one of UV-9, UV-531, UV-356, and UV-284;

[0036] The benzotriazoles include at least one of UV-327, UV-P, UV-320, UV-328, UV-350, UV-326, and UV-234.

[0037] According to another aspect of this application, a method for preparing the high cold-resistant PVC composite material described in any of the above claims is provided, comprising the following steps:

[0038] S1: The aconitic acid mixed ester, PVC resin, stabilizer and lubricant are mixed to obtain a premix;

[0039] S2: Add the premixed material to a high-speed mixer and mix at 30-80℃ for 10-60 minutes. Then add it to a two-roll open mill and mix at 130-190℃ for 5-20 minutes to obtain the compound.

[0040] S3: Place the mixture in a flat vulcanizing machine and vulcanize it at 140-190℃ and 10-15MPa for 5-15 minutes to obtain the final product.

[0041] According to another aspect of this application, applications of the high cold-resistant PVC composite material described in any of the above claims are provided, including PVC plastic film for winter greenhouses, refrigerator sealing strips, snow boot soles, skis, and blood bags. The operating temperatures in the above applications are all low, generally from -30°C to 0°C. The composite material prepared in this application still possesses sealing, heat insulation, anti-slip, and good flexibility properties at these operating temperatures, and can meet the requirements for long-term use.

[0042] The beneficial effects of this application include, but are not limited to:

[0043] 1. The high cold-resistant PVC composite material of this application uses aconitine monoester as a plasticizer. Aconitine in this plasticizer is a non-toxic and environmentally friendly bio-acid derived from microbial fermentation. As the main structure, it can improve the plasticizing efficiency of the plasticizer and effectively reduce the use of petrochemical raw materials. Furthermore, the substituents of aconitine monoester are alkyl groups with no more than 5 carbon atoms, which can give aconitine ester high compatibility, allowing it to mix better with the material matrix and provide better performance for subsequent products.

[0044] 2. The high cold-resistant PVC composite material of this application uses aconitine monoester as a plasticizer added to PVC. The macromolecular structure and benzene ring-like structure of aconitine monoester improve the compatibility with PVC, achieving the effect of highly efficient plasticizing of PVC.

[0045] 3. The aconitine monoester used in the high cold-resistant PVC composite material of this application contains a large number of short-chain esters, which have better compatibility with PVC molecular chains, effectively increasing the limit of plasticizer dosage, enabling the composite PVC material to achieve higher plasticity. On the one hand, it reduces the processing difficulty of the material, and on the other hand, it expands the application field and scope of the material.

[0046] 4. The high cold-resistant PVC composite material of this application adopts a specific aconitine monoester plasticizer, which has better compatibility with PVC materials compared with traditional plasticizers. By using it in combination with specific cold-resistant modifiers, stabilizers and lubricants, the scientific ratio of each component works synergistically to effectively enhance the stability, toughness, tensile properties and cold resistance of the composite material. Moreover, the composite material shows no obvious phase separation under scanning electron microscopy. Attached Figure Description

[0047] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0048] Figure 1 Here is a SEM image of the composite material from Example 1;

[0049] Figure 2 Here is a SEM image of the composite material from Example 2;

[0050] Figure 3 Here is a SEM image of the composite material from Example 3;

[0051] Figure 4 The image shows a SEM image of the composite material in Comparative Example 1.

[0052] Figure 5 The image shows a SEM image of the composite material in Comparative Example 2.

[0053] Figure 6 The image shows a SEM image of the composite material in Comparative Example 3.

[0054] Figure 7 The image shows a SEM image of the composite material in Comparative Example 4. Detailed Implementation

[0055] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0056] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0057] Example 1

[0058] This embodiment relates to a high cold-resistant PVC composite material and its preparation method. By weight, it comprises: 100 parts PVC resin, 50 parts triethyl aconitate, 5 parts CPE, 4 parts heat stabilizer, 1 part UV-327 light stabilizer, and 1 part ethylene bis-stearamide synthetic wax lubricant. The heat stabilizer is calcium stearate and zinc stearate in a weight ratio of 2:1. The triethyl aconitate has an acid value of 0.03 mg KOH / g, a water content of 0.05%, and a purity of 97.5%. The CPE has a chlorine content of 30%. The PVC has a degree of polymerization of 1251-1370, a polydispersity index of 4, and a K value of 71. The structural formula of triethyl aconitate is as follows:

[0059]

[0060] The preparation method of this composite material includes the following steps:

[0061] S1: A premix is ​​prepared by mixing triethyl aconitate, PVC resin, stabilizer and lubricant;

[0062] S2: Add the premix to a high-speed mixer and mix at 60°C for 40 minutes. Then add it to a two-roll open mill and mix at 155°C for 20 minutes to obtain the mixture.

[0063] S3: The compound is placed in a flat vulcanizing press with a gauge pressure of 10 MPa and vulcanized at 165°C for 15 minutes to obtain the composite material. The SEM image of this composite material is shown below. Figure 1 As shown.

[0064] Example 2

[0065] The difference between this embodiment and Embodiment 1 is that tripropyl aconitate is used. The structural formula of tripropyl aconitate is as follows:

[0066]

[0067] The aconitine tripropyl ester has an acid value of 0.07 mg KOH / g, a water content of 0.06%, and a purity of 98%. The remaining components and preparation method are the same as in Example 1. The SEM image of this composite material is shown below. Figure 2 As shown.

[0068] Example 3

[0069] The difference between this embodiment and Embodiment 1 is that aconitine tributyl aconitine is used. The structural formula of aconitine tributyl aconitine is as follows:

[0070]

[0071] The aconitine tributyl ester had an acid value of 0.005 mg KOH / g, a water content of 0.007%, and a purity of 99%. The remaining components and preparation method were the same as in Example 1. The SEM image of the composite material is shown below. Figure 3 As shown.

[0072] Example 4

[0073] The difference between this embodiment and Embodiment 1 is that trimethyl aconitate is used. The structural formula of trimethyl aconitate is as follows:

[0074]

[0075] The aconitine trimethyl ester has an acid value of 0.02 mg KOH / g, a water content of 0.03%, and a purity of 98%. The remaining components and preparation method are the same as in Example 1.

[0076] Example 5

[0077] The difference between this embodiment and Example 1 is that aconitine tripentyl aconitate is used. The structural formula of aconitine tripentyl aconitate is as follows:

[0078]

[0079] The aconitine tripentyl ester has an acid value of 0.07 mg KOH / g, a water content of 0.07%, and a purity of 97.5%. The remaining components and preparation method are the same as in Example 1.

[0080] Example 6

[0081] The difference between this embodiment and Example 1 is that aconitine triethyl ester and aconitine tributyl ester are used in a weight ratio of 1:1. The parameters of aconitine triethyl ester and aconitine tributyl ester are the same as those in Examples 1 and 3, and the remaining components and preparation methods are the same as those in Example 1.

[0082] Example 7

[0083] The difference between this embodiment and Example 1 is that the acid value of triethyl aconitate is 1.5 mg KOH / g, while the other components and preparation methods are the same as in Example 1.

[0084] Example 8

[0085] The difference between this embodiment and Example 1 is that the water content of triethyl aconitate is 2%, while the remaining components and preparation methods are the same as in Example 1.

[0086] Example 9

[0087] The difference between this embodiment and Example 1 is that the purity of triethyl aconitate is 90%, while the remaining components and preparation methods are the same as in Example 1.

[0088] Example 10

[0089] The difference between this embodiment and Example 1 is that the degree of polymerization of PVC is 1900-1950, while the other components and preparation methods are the same as in Example 1.

[0090] Example 11

[0091] The difference between this embodiment and Example 1 is that the degree of polymerization of PVC is 450-500, while the other components and preparation methods are the same as in Example 1.

[0092] Example 12

[0093] The difference between this embodiment and Example 1 is that the polydispersity index of PVC is 5.5, while the other components and preparation methods are the same as in Example 1.

[0094] Example 13

[0095] The difference between this embodiment and Example 1 is that the polydispersity index of PVC is 2.5, while the other components and preparation methods are the same as in Example 1.

[0096] Example 14

[0097] The difference between this embodiment and Embodiment 1 is that one part of CPE is used, the chlorine content of the CPE is 20%, and the remaining components and preparation methods are the same as in Embodiment 1.

[0098] Example 15

[0099] The difference between this embodiment and Example 1 is that 10 parts of EVA are used as the cold-resistant modifier, the VA content in the EVA is 30%, and the remaining components and preparation methods are the same as in Example 1.

[0100] Example 16

[0101] The difference between this embodiment and Embodiment 1 is that oxidized polyethylene wax is used as a lubricant, while the remaining components and preparation methods are the same as in Embodiment 1.

[0102] Example 17

[0103] The difference between this embodiment and Embodiment 1 is that 2 parts of heat stabilizer and 3 parts of UV-327 light stabilizer are used. The composition of the heat stabilizer, the remaining components and the preparation method are the same as in Embodiment 1.

[0104] Example 18

[0105] The difference between this embodiment and Embodiment 1 is that the heat stabilizer is calcium stearate and zinc stearate in a weight ratio of 8:1, while the remaining components and preparation methods are the same as in Embodiment 1.

[0106] Comparative Example 1

[0107] The difference between this comparative example and Example 1 is that dioctyl phthalate is used instead of triethyl aconitate; the remaining components and preparation method are the same as in Example 1. The SEM image of this composite material is shown below. Figure 4 As shown.

[0108] Comparative Example 2

[0109] The difference between this comparative example and Example 1 is that tributyl acetylacetic acid is used instead of triethyl aconitate; the remaining components and preparation methods are the same as in Example 1. The SEM image of this composite material is shown below. Figure 5 As shown.

[0110] Comparative Example 3

[0111] The difference between this comparative example and Example 1 is that dibutyl phthalate is used instead of triethyl aconitate; the remaining components and preparation methods are the same as in Example 1. The SEM image of this composite material is shown below. Figure 6 As shown.

[0112] Comparative Example 4

[0113] The difference between this comparative example and Example 1 is that dioctyl terephthalate is used instead of triethyl aconitate; the remaining components and preparation methods are the same as in Example 1. The SEM image of this composite material is shown below. Figure 7 As shown.

[0114] Comparative Example 5

[0115] The difference between this comparative example and Example 1 is that epoxidized soybean oil is used instead of triethyl aconitate, while the remaining components and preparation methods are the same as in Example 1.

[0116] Comparative Example 6

[0117] The difference between this comparative example and Example 1 is that aconitine trihexyl ester is used instead of aconitine triethyl ester. The structural formula of aconitine trihexyl ester is as follows:

[0118] The remaining components and preparation methods are the same as in Example 1.

[0119] Comparative Example 7

[0120] The difference between this comparative example and Example 1 is that aconitine dibutylisooctyl ester is used instead of triethyl aconitine. The structural formula of aconitine dibutylisooctyl ester is as follows:

[0121] The remaining components and preparation methods are the same as in Example 1.

[0122] Comparative Example 8

[0123] The difference between this comparative example and Example 1 is that it does not contain CPE, while the remaining components and preparation methods are the same as in Example 1.

[0124] Comparative Example 9

[0125] The difference between this comparative example and Example 1 is that the amount of triethyl aconitate is 4 parts, while the remaining components and preparation methods are the same as in Example 1.

[0126] Test case

[0127] The composite materials prepared in the above embodiments and comparative examples were subjected to performance tests, and the results are shown in Tables 1 and 2. The test methods are as follows:

[0128] 1. Hardness: Samples were prepared and tested according to GB / T531-2008 "Indentation Hardness Test Method, Shore Hardness Tester Method". Three points were selected for each sample group, and each point was tested once. The median value was taken. The hardness / Shore A in Table 1 is the result of the test at 25℃, which was conducted using a type A hardness tester. The hardness / Shore D in Table 2 is the result of the test at -5℃, which was conducted using a type D hardness tester. In order to facilitate the comparison of the hardness change of composite materials at low temperature, the actual measured Shore D hardness in Table 2 was converted to the hardness / Shore A value in Table 2 according to D=A-50.

[0129] 2.100% constant tensile stress, elongation at break, and modulus of elasticity: According to GB / T1040–2006 "Test for tensile properties of plastics", the tensile speed was 50 mm / min and the temperature was 25℃. The results are shown in Table 1. The modulus of elasticity of the material was tested at -5℃ using the same method. The results are shown in Table 2.

[0130] 3. Compatibility: The water valence method was used for testing. Since water molecules are polar, the compatibility of plasticizers with water can characterize their compatibility with polar materials (PVC, PLA, and nitrile rubber). When a plasticizer has good compatibility with water, it has good compatibility with PVC, and vice versa. In the experiment, 2.5g of plasticizer and 25g of acetone were added to a beaker and titrated with a burette containing deionized water while stirring until turbidity appeared. The volume of deionized water consumed was recorded.

[0131] 4. Glass transition temperature (T) g Glass transition temperature was tested using a dynamic mechanical analyzer. Test conditions: nitrogen as carrier gas, test temperature range of -40 to 80℃, heating rate of 3℃ / min, and frequency of 1Hz.

[0132] Table 1

[0133]

[0134]

[0135] Table 2

[0136]

[0137]

[0138] As shown in Tables 1 and 2, aconitine short-chain esters exhibit good compatibility with the material and maintain good plasticizing effects at low temperatures. However, when the aconitine content fails to meet patent requirements, its plasticizing performance, especially at low temperatures, significantly decreases. Furthermore, compared to composite materials plasticized with other commonly used commercial plasticizers, the PVC material formed by the aconitine ester composite used in this invention has significant advantages in compatibility and low-temperature performance.

[0139] A comparison of Example 7 and Example 1 shows that the higher the acid value of aconitine monoester, the more acidic substances will be generated in the composite material during processing, which will corrode and age the composite material, resulting in an increase in the hardness, 100% tensile stress and elastic modulus of the composite material, and a decrease in elongation at break, compatibility and cold resistance.

[0140] According to the comparison between Example 8 and Example 1, the increase in the water content of aconitine monoester will reduce the plasticizing effect of aconitine monoester on PVC resin and the synergistic effect with the cold-resistant modifier, resulting in an increase in the hardness, 100% tensile stress and elastic modulus of the composite material, but a decrease in elongation at break and cold resistance.

[0141] A comparison of Example 9 and Example 1 shows that the purity of aconitine monoester decreases, and the impurity content introduced into the composite material increases. As a result, the contact between aconitine monoester and PVC and cold-resistant modifier decreases, reducing the plasticizing performance of the composite material and decreasing its cold resistance.

[0142] A comparison of Examples 10-11 and Example 1 shows that the higher the degree of polymerization of PVC, the higher the hardness, 100% tensile stress, and elastic modulus of the composite material, while the elongation at break and cold resistance decrease. The higher the degree of polymerization, the more entangled the molecular chains become, and the less the plasticizer and cold-resistant modifier modify the PVC material. However, the compatibility with aconitine monoester remains unchanged. Therefore, PVC with a degree of polymerization in the range of 650-1800 can react and crosslink with aconitine monoester, cold-resistant modifier, lubricant, and stabilizer components to form a stable crosslinked network structure, thereby giving the composite material better toughness, plasticity, tensile strength, and cold resistance.

[0143] A comparison of Examples 13-14 and Example 1 shows that a polydispersity index of PVC resin in the range of 3-5 allows PVC resin materials of different molecular weights to come into contact with aconitine monoester, and improves the synergistic effect of aconitine monoester and cold-resistant modifier, effectively improving the toughness and cold resistance of composite materials.

[0144] According to the comparison of Examples 14-15, Comparative Examples 8-9 and Example 1, when no cold-resistant modifier is added, the relative proportion of plasticizer increases. Although the plasticizing performance increases, the cold resistance of the composite material decreases. The type, parameters and amount of cold-resistant modifier can affect the plasticizing effect of aconitine monoester on the composite material and change the cold resistance of the composite material. The addition amount of cold-resistant modifier and aconitine monoester can synergistically achieve a technical effect of 1+1>2.

[0145] A comparison of Examples 16-18 and Example 1 shows that the type and ratio of lubricant and heat stabilizer affect the plasticizing effect of aconitine monoester on the composite material, and also affect the synergistic effect of cold-resistant modifier and aconitine monoester in improving the cold resistance of the composite material.

[0146] Based on the comparison of Comparative Examples 1-7 and Example 1, it can be seen that the synergistic effect of other types of plasticizers and cold-resistant modifiers is poor. The increase in the number of carbon atoms of R in aconitine monoester will reduce the synergistic effect of aconitine monoester and cold-resistant modifier, and reduce the compatibility of aconitine monoester with PVC and the plasticizing effect on composite materials.

[0147] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A high cold-resistant PVC composite material, characterized in that, By weight, the composition includes: 100 parts PVC resin, 1-10 parts cold-resistant modifier, 5-90 parts aconitine monoester, 0.5-10 parts lubricant, and 3-20 parts stabilizer. The high cold-resistant PVC composite material... T g No higher than 30℃; The structural formula of the aconitic acid monoester is as follows: ， Where R is an alkyl group having no more than 5 carbon atoms; The aconitic acid monoester has an acid value of <0.15 mgKOH / g, a water content of <0.2%, and a purity of >97%. The degree of polymerization of the PVC resin is 650-1800, the polydispersity index is 3-5, and the K value is 55-77. The cold-resistant modifier is at least one of chlorinated polyethylene and ethylene-vinyl acetate copolymer.

2. The high cold-resistant PVC composite material according to claim 1, characterized in that, The polydispersity index of the PVC resin is 3.5-4.

5.

3. The high cold-resistant PVC composite material according to claim 1, characterized in that, The lubricant is 2-4 parts; The lubricant is at least one of oxidized polyethylene wax, glyceryl stearate, ethylene bis-stearamide synthetic wax, paraffin wax, and polyethylene wax.

4. The high cold-resistant PVC composite material according to claim 3, characterized in that, The lubricant is a synthetic wax made of ethylene bis-stearamide.

5. The high cold-resistant PVC composite material according to claim 1, characterized in that, The stabilizer is 4-7 parts; The stabilizer is at least one of a heat stabilizer and a light stabilizer.

6. The high cold-resistant PVC composite material according to claim 5, characterized in that, The weight ratio of the heat stabilizer to the light stabilizer is 2-10:0.5-4.

7. The high cold-resistant PVC composite material according to claim 6, characterized in that, The weight ratio of the heat stabilizer to the light stabilizer is 3-5:1-2.

8. The high cold-resistant PVC composite material according to claim 5, characterized in that, The heat stabilizer is selected from calcium stearate and zinc stearate in a weight ratio of 0.1-5:

1.

9. The high cold-resistant PVC composite material according to claim 5, characterized in that, The light stabilizer is at least one of benzophenones, benzotriazoles, or triazines; The benzophenones include at least one of UV-9, UV-531, UV-356, and UV-284; The benzotriazoles include at least one of UV-327, UV-P, UV-320, UV-328, UV-350, UV-326, and UV-234.

10. The high cold-resistant PVC composite material according to claim 1, characterized in that, The chlorine content in the chlorinated polyethylene is not less than 25%, and the VA content in the ethylene-vinyl acetate copolymer is 5-40%.

11. The application of the high cold-resistant PVC composite material according to any one of claims 1-10, characterized in that, This includes PVC plastic film used in winter greenhouses, refrigerator sealing strips, snow boot soles, skis, and blood bags.

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