A low temperature resistant PVC plastic and preparation method thereof

Abstract

The present application discloses a low-temperature resistant PVC plastic and a preparation method thereof, wherein the PVC plastic comprises the following raw materials in parts by weight: 100 parts of PVC resin, 30-40 parts of filler, 10-15 parts of low-temperature toughening agent, 3-6 parts of stabilizer, 10-20 parts of plasticizer, and 1-3 parts of lubricant; the low-temperature toughening agent is prepared by free radical copolymerization of comonomers, and the comonomers include styrene-butadiene latex, an organosilicon monomer with an olefin group, and an alkyl acrylate monomer in a mass ratio of 50-60:15-25:10-20; the carbon number of the alkyl group in the alkyl acrylate is 2-8; the styrene content in the styrene-butadiene latex is 15-30%. The PVC plastic of the present application has excellent low-temperature resistance, is not easy to crack in a low-temperature environment, and has good durability.

Description

Technical Field

[0001] The present application relates to the field of PVC materials, and in particular to a method for preparing low-temperature resistant PVC plastics. Background Art

[0002] As a widely used thermoplastic, polyvinyl chloride (PVC) plastic is widely used in many fields such as building materials, packaging materials, wires and cables, medical devices, automotive interiors and daily consumer goods due to its good processing performance, low cost, excellent insulation performance, chemical corrosion resistance and flame retardancy. It has strong plasticity and can produce products with specific properties through different additives and processing techniques to meet diverse market needs.

[0003] Although PVC plastic has many advantages mentioned above, its low temperature resistance is relatively poor, which has become a key factor limiting its widespread application in cold environments. Under low temperature conditions, PVC plastic is prone to embrittlement, which is manifested by a significant decrease in impact strength, loss of toughness, and even cracking, which greatly affects the service life and safety of the product. The lack of low temperature resistance has severely limited the application of PVC plastic in low temperature environments such as low temperature climates, cold chain logistics, and outdoor winter operations.

[0004] In order to improve the low temperature resistance of PVC plastics, the current technical path commonly used in the industry is to increase the amount of plasticizers. Plasticizers are additives that can increase the flexibility and plasticity of plastics. They reduce the interaction between PVC molecular chains and improve the low temperature toughness of the material. However, although this method can improve the low temperature resistance of PVC plastics to a certain extent, it also brings new problems.

[0005] Specifically, excessive addition of plasticizers will cause the solubility of the plasticizer in the PVC matrix to reach a saturated state, which will then cause migration or precipitation. This phenomenon will not only affect the appearance and feel of PVC plastics, but more importantly, the precipitated plasticizers may migrate to the environment in contact with PVC products, such as plasticizers in food packaging migrating into food, posing a potential threat to human health. In addition, the precipitation of plasticizers will also accelerate the aging process of PVC plastics, reduce their service life, increase the generation of waste, and have adverse effects on the environment. Summary of the invention

[0006] The present application provides a low-temperature resistant PVC plastic and a preparation method thereof, so as to alleviate the problem of poor low-temperature resistance of PVC plastic.

[0007] In a first aspect, the present application provides a low-temperature resistant PVC plastic, which includes the following raw materials in parts by weight:

[0008] 100 parts of PVC resin, 30-40 parts of filler, 10-15 parts of low-temperature toughening agent, 3-6 parts of stabilizer, 10-20 parts of plasticizer, 1-3 parts of lubricant;

[0009] The low-temperature toughening agent is prepared by free radical copolymerization of comonomers, wherein the comonomers include styrene-butadiene latex, an organic silicon monomer having an olefinic group, and an alkyl acrylate monomer in a mass ratio of 50-60:15-25:10-20; the carbon number of the alkyl group in the alkyl acrylate is 2-8; and the styrene content in the styrene-butadiene latex is 15-30%.

[0010] The filler in the present application is a conventional PVC filler. Exemplarily, the filler is selected from at least one of calcium carbonate, barium sulfate, carbon black, talcum powder, titanium dioxide, and PMMA.

[0011] The stabilizer in the present application is a conventional PVC heat stabilizer, such as a metal soap stabilizer, an organic tin stabilizer, an antimony stabilizer, a rare earth stabilizer, a hydrotalcite stabilizer, and the like.

[0012] Exemplarily, the metal soap stabilizer is at least one of zinc stearate, cadmium stearate, and calcium stearate.

[0013] Exemplarily, the organotin stabilizer is at least one of dibutyltin dilaurate and dibutyltin dimaleate.

[0014] Exemplarily, the antimony stabilizer is at least one of thiol antimony and carboxylate antimony.

[0015] The plasticizer in the present application is a conventional PVC plasticizer, such as an ester plasticizer, an aliphatic plasticizer, an epoxy ester plasticizer, and a phosphate ester plasticizer.

[0016] Exemplarily, the ester plasticizer is at least one of dioctyl phthalate (DOP), diisooctyl phthalate, dioctyl adipate (DOA), and dioctyl sebacate.

[0017] Exemplarily, the aliphatic plasticizer is at least one of epoxy fatty acid methyl ester (EFAME), epoxy fatty acid butyl ester (EBE), and triglyceride acetate.

[0018] Exemplarily, the epoxy ester plasticizer is at least one of epoxy soybean oil and epoxy fatty acid octyl ester.

[0019] Exemplarily, the phosphate plasticizer is at least one of triphenyl phosphate (TPP), trimethyl phosphate (TDP) and triisopropyl phosphate (TIPP).

[0020] The lubricant of the present application is a conventional PVC lubricant, including but not limited to monoglyceride, polyethylene wax, oxidized polyethylene wax, montan wax, polyester wax, and paraffin wax.

[0021] In addition, other functional additives may be added to the raw materials of the PVC plastic of the present application, including but not limited to ultraviolet absorbers, flame retardants, antioxidants, impact resistant agents, antibacterial agents, and mildewproof agents.

[0022] Preferably, the alkenyl-containing organosilicon monomer is selected from one or more of vinyltrimethoxysilane, vinyltriethoxysilane, acryloxypropyltrimethoxysilane, acryloxypropyltriethoxysilane, acryloxypropylmethyldimethoxysilane, acryloxypropylmethyldiethoxysilane and acryloxytrimethylsilane.

[0023] Preferably, the acrylic alkyl ester monomer is selected from one or more of ethyl acrylate, propyl acrylate, butyl acrylate, isooctyl acrylate and heptyl acrylate.

[0024] Preferably, the styrene content in the styrene-butadiene latex is not higher than 30%, wherein the styrene content refers to the percentage of styrene in the total amount of butadiene and styrene (comonomer raw materials).

[0025] Preferably, the solid content of the styrene-butadiene latex is 45-60%.

[0026] Preferably, the preparation method of the low-temperature toughening agent is as follows:

[0027] Stir and dissolve deionized water, emulsifier, alkyl acrylate, hydroxy acrylate, neutralizer and styrene-butadiene latex to mix uniformly to obtain a water phase material for later use;

[0028] The organosilicon monomer having alkenyl group and the molecular weight regulator are mixed evenly to obtain the oil phase material for use;

[0029] Under the condition of vacuum degree lower than -0.09MPa, add water phase material and 5-10wt% of oil phase material, heat up to 45-55°C, add 20-30wt% of redox initiator, continue to heat up, control the reaction temperature to 60-65°C, react for 10-30min, then drop the remaining oil phase material and redox initiator; keep warm at 65-70°C for 1-2h after the addition is completed, adjust the pH to 5-6 with ammonia water after the insulation, and degassing; then cool to below 45°C, adjust the pH to 6.5-7.5 with ammonia water, filter the material, condense, wash and dry to obtain the product.

[0030] Preferably, the redox initiator comprises an oxidizing agent and a reducing agent in a molar ratio of 1:1.

[0031] Exemplarily, the oxidant is selected from at least one of benzoyl peroxide, dibenzoyl peroxide, azobisisobutyronitrile, azobisisoheptylnitrile, dicumyl peroxide, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, sodium persulfate, potassium persulfate or ammonium persulfate.

[0032] Exemplarily, the reducing agent is selected from one or more of ferrous sulfate, ascorbic acid, triethylenetetramine, and tetraethylenepentamine.

[0033] Preferably, the amount of the redox initiator used is 1 to 5% of the total mass of the comonomers.

[0034] Preferably, the emulsifier is selected from anionic emulsifiers, nonionic emulsifiers or zwitterionic emulsifiers.

[0035] Exemplarily, the emulsifier is selected from sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, fatty alcohol polyoxyethylene ether or fatty acid polyoxyethylene ester.

[0036] Exemplarily, the neutralizing agent is aqueous ammonia.

[0037] Exemplarily, the molecular weight regulator is selected from one or more of tert-dodecyl mercaptan, isooctyl 3-mercaptopropionate, and ethyl 3-mercaptobutyrate.

[0038] The low-temperature toughening agent of the present application is used to improve the toughness and impact resistance of PVC resin in low-temperature environment and reduce the phenomenon of low-temperature brittle cracking. Specifically, the introduction of alkyl acrylate in the comonomer can reduce the glass transition temperature of the copolymer product, improve its rubber properties, and improve the toughness and low-temperature impact resistance of PVC resin. Styrene-butadiene latex is obtained by copolymerization of butadiene and styrene. Its participation in the reaction can enhance the rubber properties of the copolymer product, improve its molecular chain flexibility, reduce the glass transition temperature, improve toughness and low-temperature performance; at the same time, it can improve the compatibility of the copolymer product with PVC resin. In addition, the participation of organosilicon monomers with alkenyl groups in the reaction can make the product have the effect of reducing the intermolecular forces of PVC, improve its toughness and low-temperature resistance, and the introduction of organosilicon segments helps to improve the weather resistance of the polymer. It can be seen that both alkyl acrylate and organosilicon monomers achieve synergistic toughening of PVC resin through different modes of action.

[0039] It should be noted that the increase of styrene content in styrene-butadiene latex will increase the rigidity and glass transition temperature of the low-temperature toughening agent, and reduce the toughening effect.

[0040] Preferably, a benzophenone compound is grafted onto the surface of the filler.

[0041] Preferably, the preparation method of the filler is: adding an organic tin catalyst and a diisocyanate compound to a solvent, stirring evenly to obtain a mixed solution; adding the ball-milled and screened calcium carbonate to the mixed solution, stirring to react, then adding a hydroxyxylbenzene ketone compound, continuing to stir to react, filtering, washing, and drying in sequence to obtain the filler.

[0042] Preferably, the diisocyanate compound is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate and hexamethylene diisocyanate.

[0043] Preferably, the hydroxybenzophenone compound is at least one selected from 2,4-dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, and 2-hydroxy-4-n-octyloxybenzophenone.

[0044] Exemplarily, the solvent is selected from toluene, xylene or acetone.

[0045] Exemplarily, the organotin catalyst is selected from dibutyltin dilaurate or dioctyltin dilaurate.

[0046] Preferably, the mass ratio of the calcium carbonate, the diisocyanate compound, the hydroxyxylbenzene compound, and the organic tin catalyst is 100:5-8:3-6:0.1-0.3.

[0047] Preferably, the particle size of the calcium carbonate is conventionally selected, and illustratively, the D50 particle size of the calcium carbonate is 5 to 30 microns.

[0048] PVC has poor weather resistance. Ultraviolet energy is enough to break the CH bonds and C-Cl bonds in PVC, causing PVC aging, which manifests as cracks, embrittlement, whitening and other phenomena, and the mechanical properties are reduced. In addition, the above-mentioned low-temperature toughening agent of the present application introduces a butadiene segment. While the segment plays a role in toughening and volume expansion, it is easy to degrade under ultraviolet radiation due to the unsaturated double bonds, which is not conducive to improving the weather resistance of PVC plastics. For this reason, the present application can effectively improve the anti-ultraviolet degradation performance of PVC plastics by modifying the filler and introducing xylene ketone compounds.

[0049] Specifically, after high-energy ball milling, more active hydroxyl groups are exposed on the surface of calcium carbonate, which can react with diisocyanate compounds, thereby achieving chemical bonding with hydroxy-containing benzophenone under the cross-linking of the diisocyanate compounds, and firmly attaching the benzophenone compound with ultraviolet absorption to the surface of calcium carbonate. Compared with directly adding a large amount of ultraviolet absorbers, this method is less likely to have migration and precipitation phenomena, and has more outstanding durability.

[0050] Preferably, the comonomer further comprises hydroxy acrylate, and the mass ratio of the organosilicon monomer having an alkenyl group to the hydroxy acrylate is 15-25:5-10.

[0051] The hydroxy acrylate of the present application is an acrylate monomer containing a hydroxyl group, including but not limited to at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl acrylate.

[0052] The purpose of using hydroxy acrylate is to achieve a moderate connection between the filler and the low-temperature toughening agent, to achieve a better strengthening and toughening effect, and to reduce the precipitation of the filler at high dosage.

[0053] In a second aspect, the present application provides a method for preparing low-temperature resistant PVC plastic, which comprises:

[0054] According to the raw material ratio described in any one of claims 1 to 9, weigh PVC resin, filler, low-temperature toughening agent, stabilizer, plasticizer and lubricant, add them into a blender, and stir them evenly at a temperature of 110 to 140° C.;

[0055] The uniformly stirred raw materials are passed through a twin-screw extruder, melt-extruded and granulated at 140-160°C to obtain low-temperature resistant PVC plastic.

[0056] In summary, this application has the following beneficial effects:

[0057] The present application adopts a low-temperature toughening agent obtained by copolymerization of styrene-butadiene latex, an organic silicon monomer with an olefin group, and an alkyl acrylate monomer, which can reduce its glass transition temperature and intermolecular force, thereby improving the low-temperature resistance of PVC plastic. Furthermore, by introducing a benzophenone compound on the surface of the filler, the problem of PVC resin and low-temperature toughening agent being intolerant to ultraviolet light is compensated, thereby improving its weather resistance. DETAILED DESCRIPTION

[0058] Preparation examples of raw materials and / or intermediates

[0059] Preparation Example 1-1, low temperature toughening agent, the preparation method is as follows:

[0060] Dissolve sodium dodecylbenzene sulfonate in water to prepare a 2wt% emulsifier solution, add 160g butyl acrylate, 80g hydroxyethyl acrylate, 0.5g ammonia water (25wt%) and 530g styrene-butadiene latex (styrene content 20%, solid content 50%), stir and dissolve and mix evenly to obtain the aqueous phase material for use.

[0061] 210 g of vinyltrimethoxysilane and 0.7 g of tert-dodecyl mercaptan were mixed evenly to obtain an oil phase material for later use.

[0062] Under the condition of vacuum degree lower than -0.09MPa, add water phase material and 5% oil phase material, heat to 50℃, add 6g redox initiator, continue to heat, control the reaction temperature to 65℃, react for 20min, drop the remaining oil phase material and 24g redox initiator; keep warm at 70℃ for 1.5h after the addition, adjust pH to 6 with ammonia water after the heat preservation, degassing; cool to below 45℃, adjust pH to 7 with ammonia water, filter out the material, condense, wash and dry to obtain. The oxidant of the redox initiator is benzoyl peroxide, and the reducing agent is ascorbic acid, with a molar ratio of 1:1.

[0063] Preparation Example 1-2, low temperature toughening agent, the preparation method is as follows:

[0064] Dissolve sodium dodecylbenzene sulfonate in water to prepare a 2wt% emulsifier solution, add 200g butyl acrylate, 50g hydroxyethyl acrylate, 0.6g ammonia water (25wt%) and 500g styrene-butadiene latex (styrene content 30%, solid content 50%), stir and dissolve and mix evenly to obtain the aqueous phase material for use.

[0065] Mix 150 g of vinyltrimethoxysilane and 0.6 g of ethyl 3-mercaptobutyrate evenly to obtain an oil phase material for later use.

[0066] Under the condition of vacuum degree lower than -0.09MPa, add water phase material and 10wt% oil phase material, heat to 50℃, add 5g redox initiator, continue to heat, control the reaction temperature to 60℃, react for 30min, drop the remaining oil phase material and 20g redox initiator; keep warm at 70℃ for 2h after the addition, adjust pH to 6 with ammonia water after the heat preservation, degassing; cool to below 45℃, adjust pH to 7 with ammonia water, filter out the material, condense, wash and dry to obtain. The oxidant of the redox initiator is benzoyl peroxide, and the reducing agent is triethylenetetramine, and the molar ratio is 1:1.

[0067] Preparation Example 1-3, low temperature toughening agent, the preparation method is as follows:

[0068] Dissolve fatty acid polyoxyethylene ester in water to prepare a 4wt% emulsifier solution, add 100g butyl acrylate, 100g hydroxypropyl acrylate, 0.7g ammonia water (25wt%) and 600g styrene-butadiene latex (styrene content 15%, solid content 50%), stir and dissolve and mix evenly to obtain the aqueous phase material for use.

[0069] 250 g of acryloxypropyltrimethoxysilane and 0.7 g of tert-dodecyl mercaptan were mixed evenly to obtain an oil phase material for later use.

[0070] Under the condition of vacuum degree lower than -0.09MPa, add water phase material and 10wt% oil phase material, heat to 50℃, add 12g redox initiator, continue to heat, control the reaction temperature to 60℃, react for 20min, and then drop the remaining oil phase material and 28g redox initiator. After the addition is completed, keep it at 70℃ for 2h, adjust the pH to 5 with ammonia water after the insulation, and degas it; then cool it to below 45℃, adjust the pH to 7 with ammonia water, filter the material, condense, wash and dry it. Among them, the oxidant of the redox initiator is diisopropylbenzene peroxide, and the reducing agent is ferrous sulfate, and the molar ratio is 1:1.

[0071] Preparation Example 1-4, low temperature toughening agent, is different from Preparation Example 1 in that hydroxyethyl acrylate is not added.

[0072] Preparation Example 1-5, low temperature toughening agent, is different from Preparation Example 1 in that vinyltrimethoxysilane is replaced by an equal amount of butyl acrylate.

[0073] Preparation Example 1-6, low temperature toughening agent, is different from Preparation Example 1 in that butyl acrylate is replaced by an equal amount of vinyltrimethoxysilane.

[0074] Preparation Example 1-7, a low-temperature toughening agent, is different from Preparation Example 1 in that the styrene content in the styrene-butadiene latex is 40% and the solid content is 50%.

[0075] Preparation Example 2-1, filler, the preparation method is as follows:

[0076] 2.2 g of dioctyltin dilaurate and 65 g of toluene diisocyanate were added to toluene, and stirred to obtain a mixed solution. 1000 g of calcium carbonate that had been ball-milled and screened with a 1250-mesh sieve was added to the mixed solution, and stirred for reaction for 30 min. 43.5 g of 2,4-dihydroxybenzophenone was added, and the stirring reaction was continued for 1.5 h. After the reaction, the precipitate was separated and filtered out, and the precipitate was washed with toluene, then washed with deionized water, and dried to obtain the product.

[0077] Preparation Example 2-2, filler, the preparation method is as follows:

[0078] 1.1 g of dibutyltin dilaurate and 50 g of diphenylmethane diisocyanate were added to toluene, and stirred to obtain a mixed solution; 1000 g of calcium carbonate that had been ball-milled and screened with a 1250-mesh sieve was added to the mixed solution, and stirred to react for 30 min, and then 33 g of 2,4-dihydroxybenzophenone was added, and the stirring reaction was continued for 1 h. After the reaction, the precipitate was separated and filtered out, and the precipitate was washed with toluene, then washed with deionized water, and dried to obtain the product.

[0079] Preparation Example 2-3, filler, the preparation method is as follows:

[0080] 3.0 g of dibutyltin dilaurate and 78.6 g of hexamethylene diisocyanate were added to toluene and stirred to obtain a mixed solution; 1000 g of calcium carbonate that had been ball-milled and screened with a 1250-mesh sieve was added to the mixed solution and stirred for reaction for 30 min, and then 60 g of 2,2',4,4'-tetrahydroxybenzophenone was added and the stirring reaction continued for 1.5 h. After the reaction, the precipitate was separated and filtered out, and the precipitate was washed with toluene, then washed with deionized water, and dried to obtain the product.

[0081] Preparation Example 2-4, filler, is different from Preparation Example 1 in that toluene diisocyanate is not added.

[0082] Preparation Example 2-5, filler, is different from Preparation Example 1 in that 2,4-dihydroxybenzophenone is not added. Example

[0083] Example 1, a low temperature resistant PVC plastic, the preparation steps are as follows:

[0084] Weigh 1000g of SG-7 type PVC resin, 360g of the filler of Preparation Example 2-1, 130g of the low-temperature toughening agent of Preparation Example 1-1, 20g of zinc stearate, 20g of calcium stearate, 100g of dioctyl phthalate, 50g of epoxy soybean oil and 20g of polyethylene wax, mix them, add them into a blender, and stir them evenly at 120°C.

[0085] The uniformly stirred raw materials are added to a twin-screw extruder, and melt-extruded and granulated at 140-160°C to obtain low-temperature resistant PVC plastic. The temperature of the first zone of the screw extruder is 140-145°C, the temperature of the second zone is 145-150°C, the temperature of the third zone is 150-160°C, the temperature of the fourth zone is 155-160°C, and the temperature of the fifth zone is 150-155°C.

[0086] Example 2, a low temperature resistant PVC plastic, the preparation steps are as follows:

[0087] Weigh 1000g of SG-7 type PVC resin, 300g of the filler of Preparation Example 2-2, 100g of the low-temperature toughening agent of Preparation Example 1-2, 15g of zinc stearate, 20g of calcium stearate, 40g of dioctyl adipate, 60g of epoxy soybean oil and 10g of polyethylene wax, mix them, add them into a blender, and stir them evenly at 130°C.

[0088] The uniformly stirred raw materials are added to a twin-screw extruder, and melt-extruded and granulated at 140-160°C to obtain low-temperature resistant PVC plastic. The temperature of the first zone of the screw extruder is 140-150°C, the temperature of the second zone is 150-155°C, the temperature of the third zone is 155-160°C, the temperature of the fourth zone is 155-160°C, and the temperature of the fifth zone is 150-155°C.

[0089] Example 3, a low temperature resistant PVC plastic, the preparation steps are as follows:

[0090] Weigh 1000g of SG-5 type PVC resin, 400g of the filler of Preparation Example 2-3, 150g of the low-temperature toughening agent of Preparation Example 1-3, 40g of zinc stearate, 20g of calcium stearate, 80g of dioctyl phthalate, 120g of epoxy soybean oil and 20g of polyethylene wax, mix them, add them into a blender, and stir them evenly at 130°C.

[0091] The uniformly stirred raw materials are added to a twin-screw extruder, and melt-extruded and granulated at 140-160°C to obtain low-temperature resistant PVC plastic. The temperature of the first zone of the screw extruder is 140-145°C, the temperature of the second zone is 145-150°C, the temperature of the third zone is 150-155°C, the temperature of the fourth zone is 155-160°C, and the temperature of the fifth zone is 150-155°C.

[0092] Example 4, a low-temperature resistant PVC plastic, is different from Example 1 in that the low-temperature toughening agent of Preparation Example 1-1 is replaced by an equal amount of the low-temperature toughening agent of Preparation Example 1-4.

[0093] Example 5, a low-temperature resistant PVC plastic, is different from Example 1 in that the filler in Preparation Example 2-1 is replaced by an equal amount of the filler in Preparation Example 2-4.

[0094] Example 6, a low-temperature resistant PVC plastic, is different from Example 1 in that the filler in Preparation Example 2-1 is replaced by an equal amount of the filler in Preparation Example 2-5.

[0095] Example 7, a low-temperature resistant PVC plastic, is different from Example 1 in that the filler in Preparation Example 2-1 is replaced by an equal amount of calcium carbonate (passed through a 1250 mesh sieve). Comparative Example

[0096] Comparative Example 1, a low-temperature resistant PVC plastic, is different from Example 7 in that the low-temperature toughening agent of Preparation Example 1-1 is replaced by an equal amount of the low-temperature toughening agent of Preparation Example 1-5.

[0097] Comparative Example 2, a low-temperature resistant PVC plastic, is different from Example 7 in that the low-temperature toughening agent of Preparation Example 1-1 is replaced by an equal amount of the low-temperature toughening agent of Preparation Example 1-6.

[0098] Comparative Example 3, a low-temperature resistant PVC plastic, is different from Example 7 in that the low-temperature toughening agent of Preparation Example 1-1 is replaced by an equal amount of the low-temperature toughening agent of Preparation Example 1-7.

[0099] Comparative Example 4 is a low-temperature resistant PVC plastic, which differs from Example 7 in that no low-temperature toughening agent is added.

[0100] Performance testing

[0101] Test 1: Izod impact strength: According to ISO 180:2019, the Izod impact strength of the test sample is tested at room temperature (23±2℃), and the thickness of the sample strip is 4mm.

[0102] Test 2: Tensile strength, elongation: Tested in accordance with ISO 527-1 / 2:2019.

[0103] Test 3: Low temperature impact strength: According to ISO 180:2019, the cantilever beam impact strength is tested. The sample is treated at -30℃ for 4h and the thickness of the sample strip is 4mm.

[0104] Test 4: Anti-ultraviolet aging performance: The sample was placed in a QUV aging box (UVA-340 lamp) for 2000 hours, and the tensile strength and elongation retention rate were tested according to the method of Test 2.

[0105] Table 1. Test results

[0106]

[0107] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A low temperature resistant PVC plastic, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of PVC resin, 30-40 parts of filler, 10-15 parts of low-temperature toughening agent, 3-6 parts of stabilizer, 10-20 parts of plasticizer, 1-3 parts of lubricant; The low-temperature toughening agent is prepared by free radical copolymerization of comonomers, wherein the comonomers include styrene-butadiene latex, an organic silicon monomer having an olefin group, an alkyl acrylate monomer, and a hydroxy acrylate in a mass ratio of 50-60:15-25:10-20:5-10; the carbon number of the alkyl group in the alkyl acrylate is 2-8; the styrene content in the styrene-butadiene latex is 15-30%; The filler surface is grafted with a hydroxybenzophenone compound, and the preparation method of the filler is as follows: adding an organic tin catalyst and a diisocyanate compound into a solvent, stirring evenly to obtain a mixed solution; adding ball-milled and screened calcium carbonate into the mixed solution, stirring for reaction, then adding the hydroxybenzophenone compound, continuing to stir for reaction, filtering, washing, and drying in sequence to obtain the filler; the mass ratio of the calcium carbonate, the diisocyanate compound, the hydroxybenzophenone compound, and the organic tin catalyst is 100:5-8:3-6:0.1-0.

3.

2. The PVC plastic according to claim 1, characterized in that: The alkyl acrylate monomer is selected from one or more of ethyl acrylate, propyl acrylate, butyl acrylate, isooctyl acrylate and heptyl acrylate.

3. The PVC plastic according to claim 1, characterized in that: The preparation method of the low temperature toughening agent is as follows: Stir and dissolve deionized water, emulsifier, alkyl acrylate monomer, hydroxy acrylate, neutralizer and styrene-butadiene latex to obtain a water phase material for later use; The organic silicon monomer having alkenyl group and the molecular weight regulator are mixed evenly to obtain the oil phase material for use; Under the condition of vacuum degree lower than -0.09MPa, add water phase material and 5-10wt% of oil phase material, heat up to 45-55°C, add 20-30wt% of redox initiator, continue to heat up, control the reaction temperature to 60-65°C, react for 10-30min, then drop the remaining oil phase material and redox initiator; keep warm at 65-70°C for 1-2h after the addition is completed, adjust the pH to 5-6 with ammonia water after the insulation, and degassing; then cool to below 45°C, adjust the pH to 6.5-7.5 with ammonia water, filter the material, condense, wash and dry to obtain the product.

4. The plastic according to claim 1, characterized in that The diisocyanate compound is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate; the hydroxybenzophenone compound is selected from at least one of 2,4-dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, and 2-hydroxy-4-n-octyloxybenzophenone.

5. A method for preparing low-temperature resistant PVC plastic, characterized in that: The steps include: According to the raw material ratio described in any one of claims 1 to 4, weigh PVC resin, filler, low-temperature toughening agent, stabilizer, plasticizer and lubricant, add them into a mixer, and stir them evenly at a temperature of 110 to 130° C.; The uniformly stirred raw materials are passed through a twin-screw extruder, melt-extruded and granulated at 140-160°C to obtain low-temperature resistant PVC plastic.

Images