Anti-aging plastic particle and preparation method thereof

Abstract

The invention relates to the technical field of PVC (polyvinyl chloride) plastic particles, and discloses an anti-aging plastic particle and a preparation method thereof. The plastic particle comprises the following raw materials in parts by weight: 100 parts of PVC resin, 0.5-1.5 parts of a PVC-based ultraviolet light absorber, 6-10 parts of a modified flexibilizer, 18-25 parts of a plasticizer, 3-6 parts of a heat stabilizer and 1-2 parts of a lubricant, pVC resin is used as matrix resin, a modified flexibilizer is added to improve the toughness and aging resistance of a matrix, a PVC-based ultraviolet light absorber is added to improve the aging resistance of the matrix, and poor aging resistance caused by poor compatibility of a traditional micromolecular ultraviolet light absorber is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of PVC plastic particles, and in particular to an anti-aging plastic particle and a preparation method thereof. Background Art

[0002] Polyvinyl chloride (PVC) is a thermoplastic polymer produced by free radical polymerization of vinyl chloride monomers. It is one of the earliest polymer materials to be industrialized in the world. PVC has the advantages of good acid and alkali resistance, wear resistance, electrical insulation, mechanical properties and low price. Its application range is very wide, and it is widely used in daily life, packaging, building materials, agriculture, electronic appliances, etc.

[0003] However, PVC plastics are mostly used outdoors or in environments with ultraviolet light, and PVC plastics are prone to photodegradation under ultraviolet light, which reduces their aging resistance, causes breakage, powdering, and reduced mechanical properties. Traditionally, the way to improve the aging resistance of PVC plastics is to add antioxidants, ultraviolet absorbers, light stabilizers, etc., but most of these additives are small molecules, which are easy to migrate in plastics and have limited aging resistance. Therefore, it is necessary to modify PVC plastics to improve their aging resistance. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an aging-resistant plastic particle and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] An anti-aging plastic pellet comprises the following raw materials in parts by weight: 100 parts of PVC resin, 0.5-1.5 parts of PVC-based ultraviolet absorber, 6-10 parts of modified toughening agent, 18-25 parts of plasticizer, 3-6 parts of heat stabilizer, and 1-2 parts of lubricant;

[0007] The plasticizer is dioctyl phthalate, the heat stabilizer is a calcium-zinc composite stabilizer, and the lubricant is polyethylene wax;

[0008] The PVC-based ultraviolet absorber is prepared by the following steps:

[0009] Step A1, uniformly dispersing PVC resin powder in a mixture of deionized water and N,N-dimethylformamide (DMF), adding thioglycolic acid, heating to 50-60° C., stirring and reacting for 24 hours, filtering, washing, and drying to obtain carboxylated PVC;

[0010] Further, in step A1, the usage ratio of PVC resin powder, deionized water, N,N-dimethylformamide and thioglycolic acid is 3-5 g: 40 mL: 100 mL: 0.92-1.84 g;

[0011] Step A2, adding tetrahydrofuran to the carboxylated PVC and mixing and stirring evenly, then adding 1-hydroxybenzotriazole and N,N-dimethylpyridine in sequence, transferring to an ice-water bath and stirring for 30 minutes, then slowly adding dicyclohexylcarbodiimide, and vigorously stirring at 30-40° C. for 12-18 hours, distilling under reduced pressure, collecting the product, then adding ethyl acetate to the product and stirring for 15 minutes, then removing the ethyl acetate under reduced pressure, purifying, and obtaining a PVC-based ultraviolet absorber;

[0012] Furthermore, in step A2, the usage ratio of carboxylated PVC, tetrahydrofuran, 1-hydroxybenzotriazole, N,N-dimethylpyridine, dicyclohexylcarbodiimide and ethyl acetate is 4-6 g: 50 mL: 2-4 g: 0.22-0.33 g: 2.45-3.7 g: 30 mL.

[0013] The modified toughening agent is prepared by the following steps:

[0014] Step B1, 2,5-di-tert-butylhydroquinone and potassium carbonate are mixed and stirred evenly in a reactor containing acetone, and then 4-bromo-1-butene is added, and the mixture is refluxed and stirred for 12-16 hours, and the product is collected by suction filtration using a sand core funnel, and the product is then spin-dried to 10 mL, purified, and dried to obtain a functional monomer;

[0015] Further, in step B1, the usage ratio of 2,5-di-tert-butylhydroquinone, potassium carbonate, acetone and 4-bromo-1-butene is 2.22-4.45 g: 2.76-5.52 g: 30 mL: 0.9-1.8 mL;

[0016] Step B2, dispersing nano calcium carbonate evenly in a mixture of deionized water and ethanol, adding γ-methacryloxypropyltrimethoxysilane, heating to 40-50° C., stirring for 8-12 hours, filtering, washing and drying to obtain modified calcium carbonate;

[0017] Further, in step B2, the usage ratio of nano-calcium carbonate, deionized water, ethanol and γ-methacryloxypropyltrimethoxysilane is 5 g: 20 mL: 80 mL: 0.5-2 mL;

[0018] Step B3, trifluoroethyl methacrylate, functional monomer, methyl methacrylate, sodium dodecyl sulfate and deionized water are mixed and stirred for 10-20 minutes to form a pre-emulsion; then the modified calcium carbonate is dispersed in deionized water, the pH is adjusted to 7.8-8.2, potassium persulfate is added dropwise, and the temperature is raised to 80° C., the pre-emulsion is slowly added dropwise, and then an equal amount of potassium persulfate is added and stirred for reaction for 2.5-3.5 hours, filtered, washed and dried to obtain a modified toughening agent;

[0019] Further, in step B3, the usage ratio of modified calcium carbonate, deionized water, potassium persulfate and pre-emulsion is 5 g: 50 mL: 0.2-0.6 g: 23.1-30.2 g;

[0020] Furthermore, the dosage ratio of trifluoroethyl methacrylate, functional monomer, methyl methacrylate, sodium dodecyl sulfate and deionized water in the pre-emulsion of step B3 is 1-2g: 3-6g: 4-7g: 0.1-0.2g: 15mL.

[0021] A method for preparing aging-resistant plastic particles comprises the following steps:

[0022] The raw materials are weighed by weight, and the PVC resin, modified toughening agent, PVC-based ultraviolet absorber, plasticizer, heat stabilizer and lubricant are mixed and stirred evenly to form a mixture, and then the mixture is melt-extruded and granulated to obtain aging-resistant plastic particles.

[0023] Beneficial effects of the present invention:

[0024] The plastic particles in the present invention use PVC resin as the base resin, add a modified toughening agent to improve the toughness and aging resistance of the base, add a PVC-based ultraviolet absorber to improve the aging resistance of the base, and avoid the poor aging resistance caused by the poor compatibility of traditional small molecule ultraviolet absorbers.

[0025] PVC-based UV absorbers are prepared by first modifying the surface of PVC with thioglycolic acid to obtain carboxylated PVC, and then reacting carboxylated PVC with 1-hydroxybenzotriazole. PVC-based UV absorbers can significantly improve the aging resistance of the matrix because the introduced benzotriazole structure can absorb ultraviolet rays and release the absorbed ultraviolet light in the form of harmless heat energy, thereby inhibiting the photoaging process such as the de-HCl reaction in the PVC segment. At the same time, the benzotriazole structure is grafted onto the PVC molecular chain by chemical bonding to form a PVC-based UV absorber, which to a certain extent limits the migration of the benzotriazole structure in the matrix, allowing the anti-aging effect to play a long-term role. In addition, compared with traditional small molecule UV absorbers, PVC-based UV absorbers are obtained by modifying PVC as a substrate, and have better compatibility in the matrix, and thus better aging resistance.

[0026] In the modified toughening agent, 2,5-di-tert-butylhydroquinone and 4-bromo-1-butene are first reacted to obtain a functional monomer containing a double bond structure; then, a silane coupling agent containing a double bond structure is used to treat the surface of nano calcium carbonate to obtain modified calcium carbonate; finally, a polyacrylate shell structure is synthesized on the surface of the modified calcium carbonate using the modified calcium carbonate as the core, trifluoroethyl methacrylate, functional monomer and methyl methacrylate as raw materials to obtain a modified toughening agent. The modified toughening agent has a structure with calcium carbonate as the core and polyacrylate as the shell. It has excellent toughening properties in the PVC matrix because it can induce shear yield deformation of the matrix when subjected to external stress, absorb a large amount of energy, disperse stress, and avoid stress concentration; at the same time, the shell also introduces hindered phenol structure and F element, which can synergize with the ultraviolet absorber to further improve the aging resistance of the matrix. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1: PVC-based UV absorber is prepared by the following steps:

[0029] Step A1, 3g of PVC resin powder is evenly dispersed in a mixture of 40mL of deionized water and 100mL of N,N-dimethylformamide, and then 0.92g of thioglycolic acid is added, and the temperature is raised to 50°C, stirred for reaction for 24h, filtered, washed, and dried to obtain carboxylated PVC;

[0030] Step A2, add 50 mL of tetrahydrofuran to 4 g of carboxylated PVC and mix and stir evenly, then add 2 g of 1-hydroxybenzotriazole and 0.22 g of N, N-dimethylpyridine in sequence, transfer to an ice water bath and stir for 30 min, then slowly add 2.45 g of dicyclohexylcarbodiimide, and vigorously stir for 12 h at 30 ° C., distill under reduced pressure, collect the product, then add 30 mL of ethyl acetate to the product and stir for 15 min, then remove the ethyl acetate under reduced pressure, purify, and obtain a PVC-based ultraviolet absorber.

[0031] The modified toughening agent is prepared by the following steps:

[0032] Step B1, 2.22 g of 2,5-di-tert-butylhydroquinone and 2.76 g of potassium carbonate were mixed and stirred in a reactor containing 30 mL of acetone, and then 0.9 mL of 4-bromo-1-butene was added, and the mixture was refluxed and stirred for 12 h. The product was collected by suction filtration using a sand core funnel, and the product was then spin-dried to 10 mL, purified, and dried to obtain a functional monomer;

[0033] Step B2, evenly dispersing 5 g of nano calcium carbonate in a mixture of 20 mL of deionized water and 80 mL of ethanol, adding 0.5 mL of γ-methacryloxypropyltrimethoxysilane, heating to 40° C., stirring for 8 h, filtering, washing, and drying to obtain modified calcium carbonate;

[0034] Step B3, 1g of trifluoroethyl methacrylate, 3g of functional monomer, 4g of methyl methacrylate, 0.1g of sodium dodecyl sulfate and 15mL of deionized water were mixed and stirred for 10min to form a pre-emulsion; then 5g of modified calcium carbonate was dispersed in 50mL of deionized water, the pH was adjusted to 7.8, 0.1g of potassium persulfate was added dropwise, and the temperature was raised to 80°C, and then 23.1g of the pre-emulsion was slowly added dropwise, and then 0.1g of potassium persulfate was added and stirred for 2.5h, filtered, washed and dried to obtain a modified toughening agent.

[0035] Example 2: PVC-based UV absorber is prepared by the following steps:

[0036] Step A1, 4 g of PVC resin powder is evenly dispersed in a mixture of 40 mL of deionized water and 100 mL of N,N-dimethylformamide, and then 1.38 g of thioglycolic acid is added, and the temperature is raised to 55° C., stirred for reaction for 24 hours, filtered, washed, and dried to obtain carboxylated PVC;

[0037] Step A2, add 50 mL of tetrahydrofuran to 5 g of carboxylated PVC and mix and stir evenly, then add 3 g of 1-hydroxybenzotriazole and 0.27 g of N, N-dimethylpyridine in sequence, transfer to an ice water bath and stir for 30 min, then slowly add 3 g of dicyclohexylcarbodiimide, and vigorously stir at 35 ° C. for 15 h, distill under reduced pressure, collect the product, then add 30 mL of ethyl acetate to the product and stir for 15 min, then remove the ethyl acetate under reduced pressure, purify, and obtain a PVC-based ultraviolet absorber.

[0038] The modified toughening agent is prepared by the following steps:

[0039] Step B1, 3.33 g of 2,5-di-tert-butylhydroquinone and 4.14 g of potassium carbonate were mixed and stirred evenly in a reactor containing 30 mL of acetone, and then 1.35 mL of 4-bromo-1-butene was added, and the mixture was refluxed and stirred for 14 h. The product was collected by suction filtration using a sand core funnel, and the product was then spin-dried to 10 mL, purified, and dried to obtain a functional monomer;

[0040] Step B2, evenly dispersing 5 g of nano calcium carbonate in a mixture of 20 mL of deionized water and 80 mL of ethanol, adding 1 mL of γ-methacryloxypropyltrimethoxysilane, heating to 45° C., stirring for 10 h, filtering, washing, and drying to obtain modified calcium carbonate;

[0041] Step B3, 1.5g of trifluoroethyl methacrylate, 4.5g of functional monomer, 5.5g of methyl methacrylate, 0.15g of sodium dodecyl sulfate and 15mL of deionized water were mixed and stirred for 15min to form a pre-emulsion; then 5g of modified calcium carbonate was dispersed in 50mL of deionized water, the pH was adjusted to 8, 0.2g of potassium persulfate was added dropwise, and the temperature was raised to 80°C, and then 26.65g of the pre-emulsion was slowly added dropwise, and then 0.2g of potassium persulfate was added and stirred for 3h, filtered, washed and dried to obtain a modified toughening agent.

[0042] Example 3: PVC-based UV absorber is prepared by the following steps:

[0043] Step A1, evenly disperse 5g of PVC resin powder in a mixture of 40mL of deionized water and 100mL of N,N-dimethylformamide, add 1.84g of thioglycolic acid, heat to 60°C, stir to react for 24h, filter, wash and dry to obtain carboxylated PVC;

[0044] Step A2, add 50 mL of tetrahydrofuran to 6 g of carboxylated PVC and mix and stir evenly, then add 4 g of 1-hydroxybenzotriazole and 0.33 g of N, N-dimethylpyridine in sequence, transfer to an ice water bath and stir for 30 min, then slowly add 3.7 g of dicyclohexylcarbodiimide, and vigorously stir at 40 ° C for 18 h, distill under reduced pressure, collect the product, then add 30 mL of ethyl acetate to the product and stir for 15 min, then remove the ethyl acetate under reduced pressure, purify, and obtain a PVC-based ultraviolet absorber.

[0045] The modified toughening agent is prepared by the following steps:

[0046] Step B1, 4.45 g of 2,5-di-tert-butylhydroquinone and 5.52 g of potassium carbonate were mixed and stirred in a reactor containing 30 mL of acetone, and then 1.8 mL of 4-bromo-1-butene was added, and the mixture was refluxed and stirred for 16 h. The product was collected by suction filtration using a sand core funnel, and the product was then spin-dried to 10 mL, purified, and dried to obtain a functional monomer;

[0047] Step B2, evenly dispersing 5 g of nano calcium carbonate in a mixture of 20 mL of deionized water and 80 mL of ethanol, adding 2 mL of γ-methacryloxypropyltrimethoxysilane, heating to 50° C., stirring for 12 h, filtering, washing, and drying to obtain modified calcium carbonate;

[0048] Step B3, 2g of trifluoroethyl methacrylate, 6g of functional monomer, 7g of methyl methacrylate, 0.2g of sodium dodecyl sulfate and 15mL of deionized water were mixed and stirred for 20min to form a pre-emulsion; then 5g of modified calcium carbonate was dispersed in 50mL of deionized water, the pH was adjusted to 8.2, 0.1g of potassium persulfate was added dropwise, and the temperature was raised to 80°C, and then 30.2g of the pre-emulsion was slowly added dropwise, and then 0.1g of potassium persulfate was added and stirred for 3.5h, filtered, washed and dried to obtain a modified toughening agent.

[0049] Embodiment 4: A method for preparing aging-resistant plastic particles comprises the following steps:

[0050] 100 parts of PVC resin, 0.5 parts of the PVC-based ultraviolet absorber prepared in Example 1, 6 parts of the modified toughening agent prepared in Example 1, 18 parts of dioctyl phthalate, 3 parts of calcium zinc composite stabilizer, and 1 part of polyethylene wax;

[0051] The raw materials are weighed by weight, and the PVC resin, the modified toughening agent prepared in Example 1, the PVC-based ultraviolet absorber prepared in Example 1, dioctyl phthalate, calcium zinc composite stabilizer and polyethylene wax are mixed and stirred to form a mixture, and then the mixture is melt-extruded and granulated to obtain aging-resistant plastic particles.

[0052] Embodiment 5: A method for preparing aging-resistant plastic particles comprises the following steps:

[0053] 100 parts of PVC resin, 1 part of the PVC-based ultraviolet absorber prepared in Example 2, 8 parts of the modified toughening agent prepared in Example 2, 21 parts of dioctyl phthalate, 4.5 parts of calcium zinc composite stabilizer, and 1.5 parts of polyethylene wax;

[0054] The raw materials are weighed by weight, and the PVC resin, the modified toughening agent prepared in Example 2, the PVC-based ultraviolet absorber prepared in Example 2, dioctyl phthalate, calcium zinc composite stabilizer and polyethylene wax are mixed and stirred to form a mixture, and then the mixture is melt-extruded and granulated to obtain aging-resistant plastic particles.

[0055] Embodiment 6: A method for preparing aging-resistant plastic particles comprises the following steps:

[0056] 100 parts of PVC resin, 1.5 parts of PVC-based ultraviolet absorber prepared in Example 3, 10 parts of modified toughening agent prepared in Example 3, 25 parts of dioctyl phthalate, 6 parts of calcium zinc composite stabilizer, and 2 parts of polyethylene wax;

[0057] The raw materials are weighed in parts by weight, and the PVC resin, the modified toughening agent prepared in Example 3, the PVC-based ultraviolet absorber prepared in Example 3, dioctyl phthalate, calcium zinc composite stabilizer and polyethylene wax are mixed and stirred to form a mixture, and then the mixture is melt-extruded and granulated to obtain aging-resistant plastic particles.

[0058] Comparative Example 1: This comparative example is a plastic pellet, which is different from Example 6 in that a commercially available ultraviolet absorber is used instead of the PVC-based ultraviolet absorber prepared in Example 3, and the rest is the same.

[0059] Comparative Example 2: This comparative example is a plastic pellet. The difference from Example 6 is that the modified toughening agent prepared in Example 3 is replaced by a commercially available ACR toughening agent, and the rest is the same.

[0060] The plastic pellets prepared in Examples 4-6 and Comparative Examples 1-2 were made into specimens with a length of 15 mm, a width of 5 mm and a height of 2 mm for performance testing:

[0061] Aging resistance test: The tensile strength and elongation at break of the test specimens were tested before and after 2500 hours of ultraviolet irradiation. The tensile strength and elongation at break were tested according to GB / T 1040.1-2006.

[0062] The test results are shown in Table 1:

[0063] Table 1: Performance test results

[0064]

[0065] As can be seen from Table 1, after the aging performance test, the tensile strength of the plastic pellets prepared by the present invention is still maintained in the range of (16.3-18.7) MPa, and the elongation at break is maintained in the range of (287-312)%, indicating that the plastic pellets of the present invention have excellent aging resistance.

[0066] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. An aging-resistant plastic pellet, characterized in that: The method comprises the following raw materials in parts by weight: 100 parts of PVC resin, 0.5-1.5 parts of PVC-based ultraviolet absorber, 6-10 parts of modified toughening agent, 18-25 parts of plasticizer, 3-6 parts of heat stabilizer, and 1-2 parts of lubricant; The PVC-based ultraviolet absorber is prepared by the following steps: Step A1, uniformly dispersing PVC resin powder in a mixture of deionized water and N,N-dimethylformamide (DMF), adding thioglycolic acid, heating to 50-60° C., stirring and reacting for 24 hours, filtering, washing, and drying to obtain carboxylated PVC; Step A2, tetrahydrofuran is added to the carboxylated PVC and mixed and stirred evenly, and then 1-hydroxybenzotriazole and N, N-dimethylpyridine are added in sequence, transferred to an ice water bath and stirred for 30 minutes, and then dicyclohexylcarbodiimide is slowly added, and vigorously stirred at 30-40° C. for 12-18 hours, and the product is distilled under reduced pressure to collect the product, and then ethyl acetate is added to the product and stirred for 15 minutes, and then the ethyl acetate is removed under reduced pressure and purified to obtain a PVC-based ultraviolet absorber.

2. The aging-resistant plastic pellet according to claim 1, characterized in that: In step A1, the usage ratio of PVC resin powder, deionized water, N,N-dimethylformamide and thioglycolic acid is 3-5 g: 40 mL: 100 mL: 0.92-1.84 g.

3. The aging-resistant plastic pellet according to claim 1, characterized in that: In step A2, the usage ratio of carboxylated PVC, tetrahydrofuran, 1-hydroxybenzotriazole, N,N-dimethylpyridine, dicyclohexylcarbodiimide and ethyl acetate is 4-6 g:50 mL:2-4 g:0.22-0.33 g:2.45-3.7 g:30 mL.

4. The aging-resistant plastic pellet according to claim 1, characterized in that: The modified toughening agent is prepared by the following steps: Step B1, 2,5-di-tert-butylhydroquinone and potassium carbonate are mixed and stirred evenly in a reactor containing acetone, and then 4-bromo-1-butene is added, and the mixture is refluxed and stirred for 12-16 hours, and the product is collected by suction filtration using a sand core funnel, and the product is then spin-dried to 10 mL, purified, and dried to obtain a functional monomer; Step B2, dispersing nano calcium carbonate evenly in a mixture of deionized water and ethanol, adding γ-methacryloxypropyltrimethoxysilane, heating to 40-50° C., stirring for 8-12 hours, filtering, washing and drying to obtain modified calcium carbonate; Step B3, trifluoroethyl methacrylate, functional monomer, methyl methacrylate, sodium dodecyl sulfate and deionized water are mixed and stirred for 10-20 minutes to form a pre-emulsion; then the modified calcium carbonate is dispersed in deionized water, the pH is adjusted to 7.8-8.2, potassium persulfate is added dropwise, and the temperature is raised to 80°C, and then the pre-emulsion is slowly added dropwise, and then an equal amount of potassium persulfate is added and stirred for reaction for 2.5-3.5 hours, filtered, washed and dried to obtain a modified toughening agent.

5. The aging-resistant plastic pellet according to claim 4, characterized in that: In step B1, the usage ratio of 2,5-di-tert-butylhydroquinone, potassium carbonate, acetone and 4-bromo-1-butene is 2.22-4.45 g: 2.76-5.52 g: 30 mL: 0.9-1.8 mL.

6. The aging-resistant plastic pellet according to claim 4, characterized in that: In step B2, the usage ratio of nano-calcium carbonate, deionized water, ethanol and γ-methacryloxypropyltrimethoxysilane is 5g:20mL:80mL:0.5-2mL.

7. The aging-resistant plastic pellet according to claim 4, characterized in that: In step B3, the usage ratio of modified calcium carbonate, deionized water, potassium persulfate and pre-emulsion is 5 g:50 mL:0.2-0.6 g:23.1-30.2 g.

8. The aging-resistant plastic pellet according to claim 7, characterized in that: The dosage ratio of trifluoroethyl methacrylate, functional monomer, methyl methacrylate, sodium dodecyl sulfate and deionized water in the pre-emulsion of step B3 is 1-2g: 3-6g: 4-7g: 0.1-0.2g: 15mL.

9. The aging-resistant plastic pellet according to claim 1, characterized in that: The plasticizer is dioctyl phthalate, the heat stabilizer is a calcium-zinc composite stabilizer, and the lubricant is polyethylene wax.

10. A method for preparing the aging-resistant plastic particles according to any one of claims 1 to 9, characterized in that: The following steps are involved: The raw materials are weighed by weight, and the PVC resin, modified toughening agent, PVC-based ultraviolet absorber, plasticizer, heat stabilizer and lubricant are mixed and stirred evenly to form a mixture, and then the mixture is melt-extruded and granulated to obtain aging-resistant plastic particles.

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