Calcium-zinc composite stabilizer for PVC and preparation process thereof

Abstract

The application belongs to the technical field of stabilizers, and particularly relates to a calcium-zinc composite stabilizer for PVC and a preparation process. The calcium-zinc composite stabilizer for PVC comprises the following raw materials in parts by weight: calcium salt 5-10 parts, zinc salt 15-20 parts, stabilizing auxiliary agent 2-5 parts, lubricant 20-25 parts, antioxidant 1-2 parts and silane coupling agent 2-4 parts. The calcium-zinc composite stabilizer has excellent thermal stability, is used for preparing a PVC foaming plate, has good foaming effect, and meanwhile, the PVC foaming plate has excellent mechanical properties.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of stabilizers, and particularly relates to a calcium-zinc composite stabilizer for PVC and a preparation process. BACKGROUND

[0002] PVC (polyvinyl chloride) is a widely used thermoplastic plastic, but due to its poor thermal stability during processing, it usually needs to add a stabilizer to prevent its decomposition. Calcium-zinc composite stabilizer is an environmentally friendly stabilizer, which is widely used to replace traditional lead salt, cadmium soap and barium-cadmium-zinc composite stabilizer.

[0003] PVC foamed board is a kind of board formed by introducing gas into polyvinyl chloride material to form a microporous structure. This material is widely used in building decoration, industrial packaging and other fields due to its unique performance. In the manufacture of PVC foamed board, high temperature conditions are required to completely melt and plasticize the material. At the same time, due to the design characteristics of the mold (wide cross section and long runner), and the additional heat released during the decomposition of the foaming agent, higher requirements are placed on the thermal stabilizer. Only when the thermal stabilizer has sufficient thermal stability, can it effectively cope with these high temperature conditions, so as to ensure that the produced board meets the expected quality standards.

[0004] The calcium-zinc stabilizer in the prior art is mainly used to solve the problem of thermal stability of PVC material, but after adding, the mechanical properties of the product are often not paid enough attention to. At the same time, higher foaming rate means that more gas is introduced into the material, thereby reducing the overall density of the material. Although higher foaming rate can reduce weight, too high foaming rate may affect the strength of the material. How to maintain good mechanical properties at high foaming rate is a problem to be solved at present.

[0005] Chinese patent CN 107778727 A discloses a PVC micro-foamed floor environmentally friendly calcium-zinc stabilizer and its preparation method, which is composed of the following raw materials in mass percentage: calcium salt main stabilizer 2-15%, zinc salt main stabilizer 5-25%, hydrotalcite 30-50%, antioxidant 1-5%, auxiliary stabilizer 3-10%, processing fluidity aid 5-20%, heterocyclic compound 5-10%, lubricant 10-30%, which has the advantages of good product stability, good product fluidity, uniform foaming, low price and the like.

[0006] Therefore, there is an urgent need for a calcium-zinc composite stabilizer and preparation process specially for PVC foamed board. SUMMARY

[0007] The purpose of the present application is to provide a calcium-zinc composite stabilizer for PVC and a preparation process.

[0008] In order to achieve the above object, the present application provides the following technical solutions.

[0009] A calcium-zinc composite stabilizer for PVC, comprising the following raw materials in parts by weight: calcium salt 5-10 parts, zinc salt 15-20 parts, stabilizing auxiliary agent 2-5 parts, lubricant 20-25 parts, antioxidant 1-2 parts, and silane coupling agent 2-4 parts.

[0010] Further, the calcium salt comprises at least one of calcium stearate, calcium palmitate, and calcium laurate.

[0011] Further, the calcium salt is calcium stearate.

[0012] Further, the zinc salt comprises at least one of zinc stearate, zinc palmitate, and zinc laurate.

[0013] Further, the zinc salt is zinc stearate.

[0014] Further, the weight ratio of the calcium stearate and the zinc stearate is 1:2 to 1:2.5.

[0015] When the calcium-zinc composite stabilizer for PVC of the present application uses calcium stearate as the calcium salt, zinc stearate as the zinc salt, and simultaneously meets the specific addition ratio, the prepared calcium-zinc composite stabilizer for PVC has good thermal stability effect, and can also improve the tensile strength of the PVC plate. This is mainly because under this condition, the zinc content in the composite stabilizer can avoid the "zinc burning" phenomenon, and the appropriate amount of calcium can provide long-term stability; at the same time, the long-chain structure of calcium stearate and zinc stearate increases the compatibility of the composite stabilizer with the components in the PVC foaming agent, reduces the intermolecular force of PVC, and has better thermal stability effect. Calcium stearate and zinc stearate can form a bridge between the PVC molecular chains, enhance the interaction between the molecules, and a reasonable calcium-zinc ratio helps to uniformly disperse in the PVC matrix, avoids the performance inhomogeneity caused by local excessive aggregation, and thus improves the tensile strength of the PVC foaming plate.

[0016] Further, the stabilizing auxiliary agent comprises epoxy soybean oil, pentaerythritol, and polyethylene wax.

[0017] Still further, the stabilizing auxiliary agent comprises epoxy soybean oil, pentaerythritol, and polyethylene wax in a weight ratio of 1:(0.4-0.6):(1.2-1.5).

[0018] The system of the present application adds a specific proportion of a stabilizing auxiliary agent, which can not only improve the thermal stability of the calcium-zinc composite stabilizer for PVC, but also improve the bending strength of the PVC foam board. The main reason is that the specific proportion of the epoxy soybean oil, pentaerythritol and polyethylene wax produces a synergistic effect. The epoxy soybean oil has a long-chain structure. The pentaerythritol contains multiple hydroxyl functional groups, which can react with the chlorine atoms on the PVC molecular chain. The polyethylene wax can improve the flowability. Through the synergistic effect of multiple mechanisms, the internal structure and the interfacial bonding force of the material are enhanced, and the bending strength of the PVC foam board is improved.

[0019] Further, the lubricant is liquid paraffin.

[0020] Further, the antioxidant is selected from at least one of antioxidant 1010 and antioxidant 168.

[0021] Further, the silane coupling agent is selected from at least one of silane coupling agent KH792 and silane coupling agent KH602.

[0022] The present application can improve the thermal stability and foaming ratio of the calcium-zinc composite stabilizer for PVC by adding a specific type of silane coupling agent in the calcium-zinc composite stabilizer for PVC. The silane coupling agent used in the present application is a bis-amino silane coupling agent, which has two active amino groups that can react with chlorine atoms or hydroxyl groups in the PVC matrix to form chemical bonds. These chemical bonds can enhance the interfacial bonding force between the inorganic filler and the organic matrix. By enhancing the interfacial bonding force, the internal structure of the material becomes more uniform, thereby improving the overall thermal stability. The use of a specific type of silane coupling agent in the present application can promote the uniform dispersion of the foaming agent in the PVC matrix, making it easier for the bubble nuclei to be uniformly distributed, thereby improving the foaming ratio and the uniformity of the cells. In the PVC melt, a three-dimensional network structure is formed, increasing the viscosity and strength of the melt, which helps to maintain the shape of the cells and prevent cell coalescence or rupture, thereby improving the foaming ratio.

[0023] The present application also provides a preparation process of a calcium-zinc composite stabilizer for PVC, which comprises the following steps: stirring calcium salt, zinc salt and lubricant at 60-65 DEG C for 10-15 min; then adding the remaining raw materials and stirring at 60-65 DEG C for 15-20 min, and obtaining the calcium-zinc composite stabilizer for PVC after cooling.

[0024] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0025] 1. When the calcium-zinc composite stabilizer for PVC of the present application uses calcium stearate as the calcium salt, zinc stearate as the zinc salt, and simultaneously meets the specific addition ratio, the prepared calcium-zinc composite stabilizer for PVC has good thermal stability, and can also improve the tensile strength of the PVC board.

[0026] 2、The system of the present application adds a specific ratio of a stabilizing auxiliary agent, which can not only improve the thermal stability of the calcium-zinc composite stabilizer for PVC, but also improve the bending strength of the PVC foam board.

[0027] 3、The present application can improve the thermal stability of the composite stabilizer and the PVC foam board and the foaming ratio by adding a specific type of silane coupling agent to the calcium-zinc composite stabilizer for PVC. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] The raw materials used in the following embodiments of the present application are all commercially available:

[0030] Silane coupling agent KH792, Nanjing Chemical Reagent Co., Ltd.

[0031] Epoxidized soybean oil, Shandong Xirongxin Chemical Technology Co., Ltd., industrial grade.

[0032] Polyethylene wax, Shandong Baolile Plastic Additives Co., Ltd., molecular weight 1500-5000.

[0033] Liquid paraffin, Changde Hengtong Petrochemical Additives Co., Ltd.

[0034] Antioxidant 1010, Nantong Xinchang Chemical Co., Ltd.

[0035] Embodiment 1

[0036] The present embodiment provides a calcium-zinc composite stabilizer for PVC, which comprises the following raw materials in parts by weight: calcium salt 8 parts, zinc salt 16 parts, stabilizing auxiliary agent 4 parts, lubricant 22 parts, antioxidant 1.4 parts and silane coupling agent 3 parts.

[0037] The zinc salt is zinc stearate; the calcium salt is calcium stearate.

[0038] The stabilizing auxiliary agent comprises epoxidized soybean oil, pentaerythritol and polyethylene wax in a weight ratio of 1:0.5:1.3.

[0039] The lubricant is liquid paraffin; the antioxidant is antioxidant 1010.

[0040] The silane coupling agent is silane coupling agent KH792.

[0041] The preparation process of the calcium-zinc composite stabilizer for PVC comprises the following steps: stirring calcium salt, zinc salt and lubricant at 65 DEG C for 10 min; then adding the remaining raw materials, stirring at 65 DEG C for 20 min, and obtaining the calcium-zinc composite stabilizer for PVC after cooling.

[0042] Example 2

[0043] The calcium-zinc composite stabilizer for PVC comprises the following raw materials in parts by weight: calcium salt 9 parts, zinc salt 20 parts, stabilizing auxiliary 5 parts, lubricant 25 parts, antioxidant 1 part and silane coupling agent 4 parts.

[0044] The zinc salt is zinc stearate; the calcium salt is calcium stearate.

[0045] The stabilizing auxiliary comprises epoxy soybean oil, pentaerythritol and polyethylene wax in a weight ratio of 1:0.4:1.2.

[0046] The lubricant is liquid paraffin; the antioxidant is antioxidant 1010.

[0047] The silane coupling agent is silane coupling agent KH792.

[0048] The preparation process of the calcium-zinc composite stabilizer for PVC comprises the following steps: stirring calcium salt, zinc salt and lubricant at 65 DEG C for 10 min; then adding the remaining raw materials, stirring at 65 DEG C for 20 min, and obtaining the calcium-zinc composite stabilizer for PVC after cooling.

[0049] Example 3

[0050] The difference between the example and example 1 is that the parts of calcium salt and zinc salt are different.

[0051] The calcium-zinc composite stabilizer for PVC comprises the following raw materials in parts by weight: calcium salt 5 parts, zinc salt 19 parts, stabilizing auxiliary 4 parts, lubricant 22 parts, antioxidant 1.4 parts and silane coupling agent 3 parts.

[0052] The zinc salt is zinc stearate; the calcium salt is calcium stearate.

[0053] The stabilizing auxiliary comprises epoxy soybean oil, pentaerythritol and polyethylene wax in a weight ratio of 1:0.5:1.3.

[0054] The lubricant is liquid paraffin; the antioxidant is antioxidant 1010.

[0055] The silane coupling agent is silane coupling agent KH792.

[0056] The preparation process of the calcium-zinc composite stabilizer for PVC comprises the following steps: stirring calcium salt, zinc salt and lubricant at 65 DEG C for 10 min; then adding the remaining raw materials, stirring at 65 DEG C for 20 min, and obtaining the calcium-zinc composite stabilizer for PVC after cooling.

[0057] Example 4

[0058] The difference between the embodiment and example 1 is that the types of calcium salt and zinc salt are different.

[0059] The calcium-zinc composite stabilizer for PVC comprises the following raw materials in parts by weight: calcium salt 8 parts, zinc salt 16 parts, stabilizing auxiliary agent 4 parts, lubricant 22 parts, antioxidant 1.4 parts and silane coupling agent 3 parts.

[0060] The zinc salt is zinc laurate; the calcium salt is calcium laurate.

[0061] The stabilizing auxiliary agent comprises epoxy soybean oil, pentaerythritol and polyethylene wax in a weight ratio of 1:0.5:1.3.

[0062] The lubricant is liquid paraffin; the antioxidant is antioxidant 1010.

[0063] The silane coupling agent is silane coupling agent KH792.

[0064] The preparation process of the calcium-zinc composite stabilizer for PVC comprises the following steps: stirring calcium salt, zinc salt and lubricant at 65 DEG C for 10 min; then adding the remaining raw materials, stirring at 65 DEG C for 20 min, and obtaining the calcium-zinc composite stabilizer for PVC after cooling.

[0065] Example 5

[0066] The difference between the embodiment and example 1 is that the stabilizing auxiliary agent comprises epoxy soybean oil, pentaerythritol and polyethylene wax in a weight ratio of 0.5:1.3:1.

[0067] The calcium-zinc composite stabilizer for PVC comprises the following raw materials in parts by weight: calcium salt 8 parts, zinc salt 16 parts, stabilizing auxiliary agent 4 parts, lubricant 22 parts, antioxidant 1.4 parts and silane coupling agent 3 parts.

[0068] The zinc salt is zinc stearate; the calcium salt is calcium stearate.

[0069] The stabilizing auxiliary agent comprises epoxy soybean oil, pentaerythritol and polyethylene wax in a weight ratio of 0.5:1.3:1.

[0070] The lubricant is liquid paraffin; the antioxidant is antioxidant 1010.

[0071] The silane coupling agent is silane coupling agent KH792.

[0072] The preparation process of the calcium-zinc composite stabilizer for PVC includes the following steps: stirring calcium salt, zinc salt and lubricant at 65 DEG C for 10 min; then adding the remaining raw materials, stirring at 65 DEG C for 20 min, and obtaining the calcium-zinc composite stabilizer for PVC after cooling.

[0073] Comparative Example 1

[0074] The difference between the present comparative example and Example 1 is that the stabilizing auxiliary agent is epoxy soybean oil.

[0075] Comparative Example 2

[0076] The difference between the present comparative example and Example 1 is that the stabilizing auxiliary agent is pentaerythritol.

[0077] Comparative Example 3

[0078] The difference between the present comparative example and Example 1 is that the stabilizing auxiliary agent is polyethylene wax.

[0079] Comparative Example 4

[0080] The difference between the present comparative example and Example 1 is that no silane coupling agent is added.

[0081] Comparative Example 5

[0082] The difference between the present comparative example and Example 1 is that the silane coupling agent is replaced by silane coupling agent KH550.

[0083] Comparative Example 6

[0084] The difference between the present comparative example and Example 1 is that the calcium-zinc composite stabilizer for PVC is a commercially available product, specifically, PVC hard product environment-friendly composite stabilizer, model TF-720A, from Zhejiang Chuanhua Huayang Chemical Co., Ltd.

[0085] Comparative Example 7

[0086] The difference between the present comparative example and Example 1 is that Chinese patent CN 107778727 A discloses a PVC micro-foaming floor environment-friendly calcium-zinc stabilizer and a preparation method thereof, and the calcium-zinc stabilizer prepared in Example 1.

[0087] Performance test

[0088] The composition of the PVC foamed board comprises the following raw materials in parts by weight: PVC resin (Shandong Aokai Chemical Co., Ltd., SG-5) 80 parts, calcium carbonate 25 parts, AC foaming agent (azodicarbonamide) 1.5 parts, foaming stabilizing auxiliary agent (universal ACR-401, Hongming New Material Technology (Shandong) Co., Ltd.) 9 parts, lubricant (paraffin) parts, and the calcium-zinc composite stabilizer prepared in examples 1-5 and comparative examples 1-7 of the present application 2.5 parts.

[0089] The raw materials were accurately weighed and then uniformly mixed and mixed on a double-roller open mill at 185℃ for 5min to prepare a sample with a thickness of 1mm.

[0090] 1. Congo red experiment (PVC static thermal stability): according to GB / T 2917.1-2002, the oil bath temperature was controlled at 185℃, and the time taken for the Congo red test paper to turn blue was determined, which was the stability time.

[0091] 2. The sample was placed in a 200℃ heat aging oven for foaming, and the sample was taken at 120s, and the thickness of the sample was measured after cooling to calculate the foaming ratio, and the calculation formula was: thickness after foaming ÷ thickness before foaming.

[0092] 3. According to GB / T 1040.2-2022, the tensile strength and bending strength of the sample were determined.

[0093] The results are shown in Table 1.

[0094] Table 1 Performance test results

[0095] Test Congo red time min Foaming ratio Tensile strength MPa Flexural strength MPa Example 1 167 3.3 51.6 50.3 Example 2 161 3.2 50.7 49.2 Example 3 135 3.0 48.2 47.7 Example 4 137 3.1 48.5 47.1 Example 5 142 3.0 47.1 46.5 Comparative Example 1 128 2.8 42.8 40.2 Comparative Example 2 121 2.7 44.4 42.4 Comparative Example 3 125 2.8 43.6 41.8 Comparative Example 4 119 2.6 40.3 39.0 Comparative Example 5 138 2.9 46.9 45.3 Comparative Example 6 105 2.6 45.4 43.7 Comparative Example 7 114 2.4 48.7 47.4

[0096] As can be seen from Table 1, the calcium-zinc composite stabilizer for PVC prepared in examples 1-2 has excellent thermal stability, and the PVC foamed board prepared therewith has high foaming ratio and good mechanical properties, which can achieve a balance of the two and improve the performance of the calcium-zinc composite stabilizer for PVC as a whole.

[0097] In example 3, the parts of calcium salt and zinc salt are different, and in example 4, the types of calcium salt and zinc salt are different, and it can be found that the thermal stability is lower than that of example 1, and the tensile properties of the PVC foamed board are lower than those of example 1.

[0098] The epoxy soybean oil, pentaerythritol and polyethylene wax used in the stabilizing auxiliary in Example 5 have different proportions, compared with Example 1, the thermal stability of the calcium-zinc composite stabilizer for PVC decreases, and the bending strength of the PVC foamed board decreases, indicating that only the epoxy soybean oil, pentaerythritol and polyethylene wax in a specific proportion can better realize the synergistic effect. The specific proportion of epoxy soybean oil, pentaerythritol and polyethylene wax used in Example 1 produces a synergistic effect, the epoxy soybean oil has a long-chain structure; the pentaerythritol contains multiple hydroxyl functional groups, which can react with the chlorine atoms on the PVC molecular chain; the polyethylene wax can improve the flowability, and through the synergistic effect of multiple mechanisms, the internal structure and the interfacial bonding force of the material are enhanced, and the bending strength of the PVC foamed board is improved.

[0099] In Comparative Examples 1-3, a single type of stabilizing auxiliary is used, compared with Example 1, the thermal stability of the calcium-zinc composite stabilizer for PVC decreases, and the bending strength of the PVC foamed board decreases, indicating that the use of a single type of stabilizing auxiliary in the present application does not achieve satisfactory improvement in the bending strength of the PVC foamed board. The chain length of calcium stearate and zinc stearate in Example 1 is longer than that of zinc laurate and calcium laurate used in Example 4, and calcium stearate and zinc stearate increase the compatibility of the composite stabilizer with the components in the PVC foaming agent, reduce the intermolecular force of PVC, and have better thermal stability. Calcium stearate and zinc stearate can form a bridge between PVC molecular chains, enhance the intermolecular interaction, and a reasonable calcium-zinc ratio helps to uniformly disperse in the PVC matrix, avoiding performance inhomogeneity caused by local excessive aggregation, thereby improving the tensile strength of the PVC foamed board.

[0100] In Comparative Example 4, no silane coupling agent is added, and the thermal stability of the composite stabilizer and the foaming ratio of the PVC foamed board decrease.

[0101] In Comparative Example 5, a silane coupling agent with one amino group is used, and the improvement effect on the thermal stability of the composite stabilizer and the PVC foamed board and the foaming ratio is lower than that of Example 1, indicating that the double amino silane coupling agent has better compatibility improvement effect on the system of the present application, and also has better improvement effect on the foaming effect. The silane coupling agent used in Example 1 is a double amino silane coupling agent, which has two active amino groups that can react with chlorine atoms or hydroxyl groups in the PVC matrix to form chemical bonds. This chemical bond can enhance the interfacial bonding force between inorganic fillers and organic matrix, and by enhancing the interfacial bonding force, the internal structure of the material is more uniform, thereby improving the overall thermal stability. The use of a specific type of silane coupling agent in Example 1 can promote the uniform dispersion of the foaming agent in the PVC matrix, making the bubble nucleus more easily and uniformly distributed, thereby improving the foaming ratio and the uniformity of the cells, forming a three-dimensional network structure in the PVC melt, increasing the viscosity and strength of the melt, and helping to maintain the shape of the cells, preventing cell coalescence or rupture, thereby improving the foaming ratio.

[0102] Comparative Example 6 uses a commercially available composite stabilizer, and the foaming ratio is lower than that of Example 1, and the mechanical properties are not ideal.

[0103] Comparative Example 7 uses a composite stabilizer prepared according to the prior art, and the thermal stability is lower than that of Example 1.

[0104] The above describes the preferred embodiments of the present application. It should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A calcium-zinc composite stabilizer for PVC, characterized in that, The raw materials include the following components by weight: calcium salt 5-10 parts, zinc salt 15-20 parts, stabilizing auxiliary 2-5 parts, lubricant 20-25 parts, antioxidant 1-2 parts, and silane coupling agent 2-4 parts; The zinc salt is zinc stearate; the calcium salt is calcium stearate; the weight ratio of calcium stearate to zinc stearate is 1:2-1:2.5; The stabilizing auxiliary is a mixture of epoxidized soybean oil, pentaerythritol and polyethylene wax in a weight ratio of 1:(0.4-0.6):(1.2-1.5); The silane coupling agent is at least one of silane coupling agent KH792 and silane coupling agent KH602.

2. The calcium-zinc complex stabilizer for PVC according to claim 1, characterized in that, The lubricant is liquid paraffin; the antioxidant is at least one of antioxidant 1010 and antioxidant 168.

3. A process for the preparation of the calcium-zinc complex stabilizer for PVC according to any one of claims 1-2, characterized in that, The method comprises the following steps: stirring the calcium salt, zinc salt and lubricant at 60-65°C for 10-15 min; then adding the remaining raw materials and stirring at 60-65°C for 15-20 min; and obtaining the calcium-zinc composite stabilizer for PVC after cooling.