A preparation method of PVC plasticizer paste

Abstract

The present invention relates to the technical field of polyvinyl chloride, and particularly relates to a preparation method of a PVC plasticizer paste. The preparation method is as follows: by weight, 5-20 parts of PVC paste resin, 3-15 parts of composite modified calcium carbonate, and 1-5 parts of plasticizer are mixed and stirred at a speed of 800-1200 rpm for 15-30 minutes to obtain a PVC plasticizer paste; in the present invention, polyethylene glycol methyl ether acrylate and octadecene are used as composite modifiers, and through a polymerization reaction, they are grafted onto the surface of vinyl silane modified calcium carbonate to obtain composite modified calcium carbonate. The PVC paste plasticizer paste prepared by the present invention has stable low-viscosity characteristics, and moreover, its products have high mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of polyvinyl chloride, and particularly to a preparation method of PVC plasticizer paste. Background Art

[0002] In the plastic industry, polyvinyl chloride (PVC) is widely used in fields such as construction, automotive, and medical due to its excellent physical and chemical properties, easy processability, and cost-effectiveness. Especially, PVC plasticizer paste has become an ideal material for producing coated, impregnated, sprayed, and molded products due to its unique rheological properties and processing adaptability.

[0003] Calcium carbonate, as a commonly used inorganic filler, is used in PVC plasticizer paste to improve mechanical properties, reduce costs, and improve thermal stability. However, due to the frequent agglomeration of calcium carbonate particles in the matrix, the dispersion is poor, which instead impairs the mechanical properties and processing properties of the polymer system. Therefore, how to solve the problem of calcium carbonate agglomeration in the matrix while improving the properties of PVC paste resin is a difficult problem that materials scientists urgently need to solve.

[0004] Patent technical literature CN201510946405.9 discloses a surface treatment method for nano-calcium carbonate filled in PVC plasticizer paste, using a compound mixture of saturated fatty acid and sodium ricinoleate sulfate to treat the nano-calcium carbonate. The treated nano-calcium carbonate can effectively improve the thixotropy, yield value, and rheological stability of the filled PVC plasticizer paste, etc. However, the saturated fatty acid and sodium ricinoleate sulfate are physically adsorbed on the surface of calcium carbonate and are easily detached, thus affecting the storage stability of the PVC plasticizer paste. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to propose a preparation method of PVC plasticizer paste to solve the problem that the stability of calcium carbonate in the calcium carbonate-filled modified PVC plasticizer paste is poor, and with the passage of time, the agglomeration is serious, resulting in poor storage stability of the PVC plasticizer paste.

[0006] Based on the above purpose, the present invention provides a preparation method of PVC plasticizer paste. By weight, 5 - 20 parts of PVC paste resin, 3 - 15 parts of compound modified calcium carbonate, and 1 - 5 parts of plasticizer are mixed and stirred at a speed of 800 - 1200 rpm for 15 - 30 min to obtain the PVC plasticizer paste.

[0007] Preferably, the PVC paste resin is prepared by the seed emulsion method, and the degree of polymerization is 1500 - 2100.

[0008] Preferably, the plasticizer is one or a mixture of dioctyl phthalate and tributyl acetylcitrate.

[0009] More preferably, the plasticizer is a mixture of dioctyl phthalate and tributyl acetylcitrate in a weight ratio of 3:1.

[0010] Furthermore, the preparation method of the composite modified calcium carbonate is as follows:

[0011] (1) Graft calcium carbonate with silane coupling agent KH-570 to obtain vinyl silane modified calcium carbonate;

[0012] (2) Use polyethylene glycol methyl ether acrylate and 1-octadecene as composite modifiers, and graft them onto the surface of vinyl silane modified calcium carbonate through a polymerization reaction to obtain composite modified calcium carbonate.

[0013] Preferably, the dosage of the silane coupling agent in step (1) is 1%-5% of the weight of calcium carbonate.

[0014] Preferably, the average particle size of calcium carbonate in step (1) is 80-100nm.

[0015] Preferably, the specific preparation steps of vinyl silane modified calcium carbonate in step (1) are as follows: Add calcium carbonate to a mixed solution of deionized water and absolute ethanol, ultrasonically disperse for 5-20min, then add silane coupling agent KH-570, raise the temperature to 40-50°C, stir for 8-15h, after the reaction is completed, wash and dry to obtain vinyl silane modified calcium carbonate.

[0016] Preferably, the weight ratio of the composite modifier to vinyl silane modified calcium carbonate in step (2) is 2-5:1;

[0017] Preferably, the molar ratio of polyethylene glycol methyl ether acrylate to 1-octadecene in step (2) is 1:2-8.

[0018] Preferably, the weight average molecular weight of polyethylene glycol methyl ether acrylate in step (2) is 400-500.

[0019] Preferably, the initiator used in the polymerization reaction in step (2) is azobisisobutyronitrile.

[0020] Preferably, the temperature of the polymerization reaction in step (2) is 55-65°C and the time is 20-30h.

[0021] The beneficial effects of the present invention:

[0022] Through the composite modification of calcium carbonate, the present invention enables it to be uniformly dispersed in the PVC plasticizer paste, showing good compatibility. This characteristic effectively reduces the system viscosity and scratch particle size of the plasticizer paste, avoids problems such as sticking rollers during the production process, and thus improves production efficiency. At the same time, it has stable low-viscosity characteristics, excellent storage stability, and is convenient for transportation and long-term storage.

[0023] In the present invention, polyethylene glycol methyl ether acrylate is introduced onto the surface of calcium carbonate. Through the lubricating effect of its ether chain, not only the viscosity of the system is reduced, but also the good fluidity and dispersibility of calcium carbonate are promoted. Especially under the synergistic effect with plasticizers, the flexibility and mobility of polymer chains are increased, the entanglement between chains is reduced, and the processing performance of the material is further improved.

[0024] In the present invention, 1-octadecene is further introduced onto the surface of calcium carbonate. Due to its unique long-chain alkyl effect, the agglomeration phenomenon of calcium carbonate in PVC plasticized paste is reduced, not only the viscosity of the system is decreased, but also the mechanical properties of its products are improved.

[0025] The present invention shows a synergistic effect in improving the tensile strength and elongation at break of PVC plasticized paste products by using the composite modification of calcium carbonate. Especially, the significant improvement of the elongation at break by the ether chain is attributed to the strengthening effect of calcium carbonate and the toughening effect of its surface alkyl chain and ether chain.

[0026] The present invention further precisely controls the mechanical properties of PVC plasticized paste products by optimizing the dosages of polyethylene glycol methyl ether acrylate and 1-octadecene. Detailed implementation manners

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the following further details the present invention with specific embodiments.

[0028] In the examples and comparative examples of the present invention, the weight-average molecular weight of the polyethylene glycol methyl ether acrylate used is 480; the PVC paste resin is prepared by the seed emulsion method, and the degree of polymerization is 1500 - 2100; the calcium carbonate is cubic-like, and the average particle size is 90 nm.

[0029] Example 1: (1) Add 5 g of calcium carbonate to a mixed solution of 10 g of deionized water and 90 g of absolute ethanol, ultrasonically disperse for 10 min, then add 0.15 g of silane coupling agent KH-570, raise the temperature to 45 °C, stir for 12 h. After the reaction is completed, wash with deionized water and absolute ethanol three times respectively, and dry at 60 °C for 24 h to obtain vinyl silane-modified calcium carbonate;

[0030] (2) Add 4.6 g of polyethylene glycol methyl ether acrylate and 10 g of 1-octadecene to absolute ethanol, stir for 30 min, then add 5 g of vinyl silane-modified calcium carbonate, ultrasonically for 20 min, then add 0.15 g of azobisisobutyronitrile, raise the temperature to 60 °C, stir for 24 h, centrifuge, wash with absolute ethanol three times, and dry at 60 °C for 12 h to obtain composite-modified calcium carbonate;

[0031] (3) Mix 10 g of PVC paste resin, 7.5 g of compound modified calcium carbonate, and 2 g of dioctyl phthalate, and stir at a speed of 1000 rpm for 20 min to obtain PVC plasticized paste.

[0032] Example 2: (1) Add 5 g of calcium carbonate to a mixture of 10 g of deionized water and 90 g of absolute ethanol, ultrasonically disperse for 5 min, then add 0.05 g of silane coupling agent KH-570, raise the temperature to 40 °C, stir for 8 h. After the reaction is completed, wash three times with deionized water and absolute ethanol respectively, and dry at 60 °C for 24 h to obtain vinyl silane modified calcium carbonate;

[0033] (2) Add 5 g of poly(ethylene glycol) methyl ether acrylate and 5 g of 1-octadecene to absolute ethanol, stir for 20 min, then add 5 g of vinyl silane modified calcium carbonate, ultrasonically for 15 min, then add 0.1 g of azobisisobutyronitrile, raise the temperature to 55 °C, stir for 20 h, centrifuge, wash three times with absolute ethanol, and dry at 60 °C for 12 h to obtain compound modified calcium carbonate;

[0034] (3) Mix 5 g of PVC paste resin, 3 g of compound modified calcium carbonate, and 1 g of dioctyl phthalate, and stir at a speed of 800 rpm for 15 min to obtain PVC plasticized paste.

[0035] Example 3: (1) Add 5 g of calcium carbonate to a mixture of 10 g of deionized water and 90 g of absolute ethanol, ultrasonically disperse for 20 min, then add 0.25 g of silane coupling agent KH-570, raise the temperature to 50 °C, stir for 15 h. After the reaction is completed, wash three times with deionized water and absolute ethanol respectively, and dry at 60 °C for 24 h to obtain vinyl silane modified calcium carbonate;

[0036] (2) Add 5 g of poly(ethylene glycol) methyl ether acrylate and 20 g of 1-octadecene to absolute ethanol, stir for 40 min, then add 5 g of vinyl silane modified calcium carbonate, ultrasonically for 30 min, then add 0.25 g of azobisisobutyronitrile, raise the temperature to 65 °C, stir for 30 h, centrifuge, wash three times with absolute ethanol, and dry at 60 °C for 12 h to obtain compound modified calcium carbonate;

[0037] (3) Mix 20 g of PVC paste resin, 15 g of compound modified calcium carbonate, and 5 g of dioctyl phthalate, and stir at a speed of 1200 rpm for 30 min to obtain PVC plasticized paste.

[0038] Example 4: (1) Add 5 g of calcium carbonate to a mixture of 10 g of deionized water and 90 g of absolute ethanol, ultrasonically disperse for 10 min, then add 0.15 g of silane coupling agent KH-570, heat up to 45 °C, stir for 12 h. After the reaction is completed, wash with deionized water and absolute ethanol three times respectively, and dry at 60 °C for 24 h to obtain vinylsilane-modified calcium carbonate;

[0039] (2) Add 4.6 g of polyethylene glycol methyl ether acrylate and 10 g of octadecene to absolute ethanol, stir for 30 min, then add 5 g of vinylsilane-modified calcium carbonate, ultrasonically for 20 min, then add azobisisobutyronitrile, heat up to 60 °C, stir for 24 h, centrifuge, wash with absolute ethanol three times, and dry at 60 °C for 12 h to obtain composite-modified calcium carbonate;

[0040] (3) Mix 10 g of PVC paste resin, 7.5 g of composite-modified calcium carbonate, 1.5 g of dioctyl phthalate and 0.5 g of tributyl acetylcitrate, and stir at a speed of 1000 rpm for 20 min to obtain PVC plasticized paste.

[0041] Comparative Example 1:

[0042] The difference between Comparative Example 1 and Example 1 is that the composite-modified calcium carbonate in step (3) is replaced by vinylsilane-modified calcium carbonate;

[0043] The specific preparation steps are as follows:

[0044] (1) Add 5 g of calcium carbonate to a mixture of 10 g of deionized water and 90 g of absolute ethanol, ultrasonically disperse for 10 min, then add 0.15 g of silane coupling agent KH-570, heat up to 45 °C, stir for 12 h. After the reaction is completed, wash with deionized water and absolute ethanol three times respectively, and dry at 60 °C for 24 h to obtain vinylsilane-modified calcium carbonate;

[0045] (2) Mix 10 g of PVC paste resin, 7.5 g of vinylsilane-modified calcium carbonate and 2 g of dioctyl phthalate, and stir at a speed of 1000 rpm for 20 min to obtain PVC plasticized paste.

[0046] Comparative Example 2:

[0047] The difference between Comparative Example 2 and Example 1 is that polyethylene glycol methyl ether acrylate was not added in step (2);

[0048] The specific preparation steps are as follows:

[0049] (1) Add 5 g of calcium carbonate to a mixture of 10 g of deionized water and 90 g of absolute ethanol, ultrasonically disperse for 10 min, then add 0.15 g of silane coupling agent KH-570, raise the temperature to 45 °C, stir for 12 h. After the reaction is completed, wash three times with deionized water and absolute ethanol respectively, and dry at 60 °C for 24 h to obtain vinylsilane-modified calcium carbonate;

[0050] (2) Add 14.6 g of 1-octadecene to absolute ethanol, stir for 30 min, then add 5 g of vinylsilane-modified calcium carbonate, ultrasonically for 20 min, then add 0.15 g of azobisisobutyronitrile, raise the temperature to 60 °C, stir for 24 h, centrifuge, wash three times with absolute ethanol, and dry at 60 °C for 12 h to obtain composite-modified calcium carbonate;

[0051] (3) Mix 10 g of PVC paste resin, 7.5 g of composite-modified calcium carbonate and 2 g of dioctyl phthalate, and stir at a speed of 1000 rpm for 20 min to obtain PVC plasticized paste.

[0052] Comparative Example 3:

[0053] The difference between Comparative Example 3 and Example 1 is that: 1-octadecene was not added in step (2);

[0054] The specific steps are as follows:

[0055] (1) Add 5 g of calcium carbonate to a mixture of 10 g of deionized water and 90 g of absolute ethanol, ultrasonically disperse for 10 min, then add 0.15 g of silane coupling agent KH-570, raise the temperature to 45 °C, stir for 12 h. After the reaction is completed, wash three times with deionized water and absolute ethanol respectively, and dry at 60 °C for 24 h to obtain vinylsilane-modified calcium carbonate;

[0056] (2) Add 14.6 g of poly(ethylene glycol) methyl ether acrylate to absolute ethanol, stir for 30 min, then add 5 g of vinylsilane-modified calcium carbonate, ultrasonically for 20 min, then add 0.15 g of azobisisobutyronitrile, raise the temperature to 60 °C, stir for 24 h, centrifuge, wash three times with absolute ethanol, and dry at 60 °C for 12 h to obtain composite-modified calcium carbonate;

[0057] (3) Mix 10 g of PVC paste resin, 7.5 g of composite-modified calcium carbonate and 2 g of dioctyl phthalate, and stir at a speed of 1000 rpm for 20 min to obtain PVC plasticized paste.

[0058] Comparative Example 4:

[0059] The difference between Comparative Example 4 and Example 1 is that: the molar ratio of poly(ethylene glycol) methyl ether acrylate to 1-octadecene in step (2) is 4:1.

[0060] The specific steps are as follows:

[0061] (1) Add 5 g of calcium carbonate to a mixture of 10 g of deionized water and 90 g of absolute ethanol, ultrasonically disperse for 10 min, then add 0.15 g of silane coupling agent KH-570, raise the temperature to 45 °C, stir for 12 h. After the reaction is completed, wash three times with deionized water and absolute ethanol respectively, and dry at 60 °C for 24 h to obtain vinyl silane modified calcium carbonate;

[0062] (2) Add 18.4 g of polyethylene glycol methyl ether acrylate and 2.5 g of 1-octadecene to absolute ethanol, stir for 30 min, then add 5 g of vinyl silane modified calcium carbonate, ultrasonically for 20 min, then add 0.15 g of azobisisobutyronitrile, raise the temperature to 60 °C, stir for 24 h, centrifuge, wash three times with absolute ethanol, and dry at 60 °C for 12 h to obtain composite modified calcium carbonate;

[0063] (3) Mix 10 g of PVC paste resin, 7.5 g of composite modified calcium carbonate and 2 g of dioctyl phthalate, and stir at a speed of 1000 rpm for 20 min to obtain PVC plasticized paste.

[0064] Performance test:

[0065] Test the viscosity and scratch particle size of the PVC plasticized paste prepared in the examples and comparative examples. The results are shown in Table 1. Make PVC test pieces according to the standard baking sheet method, and test the tensile strength and elongation at break. The results are shown in Table 2.

[0066] Table 1 Test results of viscosity and scratch particle size

[0067]

[0068] Data analysis:

[0069] From the data of Examples 1-4 in Table 1, it can be seen that the PVC plasticized paste provided by the present invention has a lower viscosity and a smaller scratch particle size, indicating that the composite modified calcium carbonate is uniformly dispersed in the PVC plasticized paste and has excellent compatibility with the PVC plasticized paste. The appropriate viscosity helps to avoid phenomena such as sticking rollers during the production process on the machine, improving production efficiency; moreover, the PVC plasticized paste prepared by the present invention has a stable viscosity within 0-12 hours, indicating its excellent stability and facilitating storage.

[0070] From Examples 1 and Comparative Example 1 in Table 1, it can be seen that the composite modification of calcium carbonate helps to reduce the system viscosity and scratch particle size of the PVC plasticized paste and improve the stability. The improvement of stability may be due to the lubricating effect of polyethylene glycol methyl ether acrylate and the synergistic dispersion effect of 1-octadecene.

[0071] As can be seen from Examples 1 and Comparative Example 2 in Table 1, the use of poly(ethylene glycol) methyl ether acrylate can effectively reduce the system viscosity of PVC plasticized paste. This is mainly because the ether chain of poly(ethylene glycol) methyl ether acrylate helps to promote the flow of calcium carbonate in the system, and, in cooperation with the plasticizer, increases the flexibility of the polymer chain and the mobility of the segments, reducing the entanglement between polymer chains.

[0072] As can be seen from Examples 1 and Comparative Example 3 in Table 1, the use of 1-octadecene can effectively reduce the system viscosity of PVC plasticized paste. This is mainly because the alkyl long chain of 1-octadecene can reduce the agglomeration of calcium carbonate in PVC plasticized paste.

[0073] As can be seen from Examples 1 and Comparative Example 4 in Table 1, the dosages of poly(ethylene glycol) methyl ether acrylate and 1-octadecene have a significant impact on the stability of PVC plasticized paste.

[0074] Table 2 Mechanical Properties of PVC Specimens

[0075] PVC Specimen Tensile Strength / MPa Elongation at Break / % Example 1 18.4 482 Example 2 17.2 512 Example 3 17.8 495 Example 4 19.3 489 Comparative Example 1 17.3 463 Comparative Example 2 19.2 454 Comparative Example 3 16.7 498 Comparative Example 4 16.9 491

[0076] Data Analysis:

[0077] As can be seen from the data of Examples 1-4 in Table 2, the PVC specimens prepared from the PVC plasticized paste provided by the present invention have excellent mechanical properties.

[0078] As can be seen from the data of Examples 1 and Comparative Examples 1-3 in Table 2, the composite modification of calcium carbonate helps to simultaneously improve the tensile strength and elongation at break of PVC specimens. Among them, the ether chain has the most significant effect on the elongation at break of PVC specimens. This may be due to the strengthening effect of calcium carbonate itself and the toughening effect of the alkyl chain and ether chain on the surface of calcium carbonate.

[0079] As can be seen from the data of Examples 1 and Comparative Example 4 in Table 2, the dosages of poly(ethylene glycol) methyl ether acrylate and 1-octadecene are crucial for adjusting the tensile strength and elongation at break of PVC specimens. When the dosage of poly(ethylene glycol) methyl ether acrylate is too much, the tensile strength of PVC specimens will be greatly reduced.

[0080] Those of ordinary skill in the art should understand that: the discussion of any above embodiment is only exemplary, and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features between the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A preparation method of PVC plasticizer paste, characterized in that, By weight parts, 5 - 20 parts of PVC paste resin, 3 - 15 parts of composite modified calcium carbonate and 1 - 5 parts of plasticizer are mixed and stirred at a speed of 800 - 1200 rpm for 15 - 30 min to obtain PVC plasticized paste; The preparation method of the composite modified calcium carbonate is as follows: (1) Calcium carbonate is grafted with silane coupling agent KH - 570 to obtain vinyl silane modified calcium carbonate; (2) Polyethylene glycol methyl ether acrylate and octadecene are used as composite modifiers and grafted onto the surface of vinyl silane modified calcium carbonate through a polymerization reaction to obtain composite modified calcium carbonate; In the step (1), the dosage of the silane coupling agent is 1% - 5% of the weight of calcium carbonate; In the step (2), the weight ratio of the composite modifier to vinyl silane modified calcium carbonate is 2 - 5:1; In the step (2), the molar ratio of polyethylene glycol methyl ether acrylate to octadecene is 1:2 - 8.

2. The preparation method of the PVC plasticizer paste according to claim 1, characterized in that, The PVC paste resin is prepared by the seed emulsion method with a degree of polymerization of 1500 - 2100.

3. The preparation method of the PVC plasticized paste according to claim 1, characterized in that, The plasticizer is one or a mixture of dioctyl phthalate and tributyl acetylcitrate.

4. The preparation method of the PVC plasticizer paste according to claim 3, characterized in that, The plasticizer is a mixture of dioctyl phthalate and tributyl acetylcitrate in a weight ratio of 3:

1.

5. The preparation method of the PVC plasticized paste according to claim 1, characterized in that, In the step (1), the average particle size of calcium carbonate is 80 - 100 nm.

6. The preparation method of the PVC plasticized paste according to claim 1, characterized in that, The specific preparation steps of vinyl silane modified calcium carbonate in the step (1) are as follows: Calcium carbonate is added to a mixed solution of deionized water and absolute ethanol, ultrasonically dispersed for 5 - 20 min, then silane coupling agent KH - 570 is added, the temperature is raised to 40 - 50 °C, and stirred for 8 - 15 h. After the reaction is completed, it is washed and dried to obtain vinyl silane modified calcium carbonate.

7. The preparation method of the PVC plasticized paste according to claim 1, characterized in that, In the step (2), the weight - average molecular weight of polyethylene glycol methyl ether acrylate is 400 - 500.

8. The preparation method of the PVC plasticized paste according to claim 1, characterized in that, In the step (2), the initiator used in the polymerization reaction is azobisisobutyronitrile.

9. The preparation method of the PVC plasticizer paste according to claim 1, characterized in that, In the step (2), the temperature of the polymerization reaction is 55 - 65 °C and the time is 20 - 30 h.

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