Transparent PVC processing modifier and preparation method thereof

Abstract

The invention provides a transparent PVC processing modifier and a preparation method thereof, and belongs to the field of PVC processing modifiers. The preparation method of the transparent PVC processing modifier comprises the following steps: first-stage reaction and second-stage reaction. According to the preparation method of the transparent PVC processing modifier disclosed by the invention, the transparency and haze of a polyvinyl chloride product can be improved and the fracture toughness of the polyvinyl chloride product in a low-temperature environment can be improved while the melt viscosity of polyvinyl chloride is reduced, the flowability of a polyvinyl chloride melt is improved and the processing molding performance is improved; the adverse effect of a transparent PVC processing modifier on a polyvinyl chloride melt is avoided, the processing torque is adjusted and stabilized, and the thermal stability of a polyvinyl chloride product is improved.

Description

Technical Field

[0001] The invention relates to the field of PVC processing modifiers, in particular to a transparent PVC processing modifier and a preparation method thereof. Background Art

[0002] Polyvinyl chloride (PVC) is one of the most widely used plastics due to its good flame retardancy, wear resistance, chemical corrosion resistance, comprehensive mechanical properties, product transparency, electrical insulation and easy processing. It is widely used in industry, construction, agriculture, daily life, packaging, electricity, public utilities and other fields. It is known as the five general-purpose resins together with polyethylene (PE), polypropylene (PP), polystyrene (PS) and ABS. However, the existing polyvinyl chloride has the disadvantages of high melt viscosity, poor fluidity, narrow molding temperature range, easy coking and decomposition, and uneven processing and molding performance. Therefore, processing modifiers must be added during the processing of PVC products.

[0003] Acrylate copolymer (ACR) is the main processing modifier in PVC processing, which can significantly shorten the plasticizing time, accelerate melting and promote plasticizing. Acrylate resin (ACR) is a thermoplastic graft polymer obtained mainly from methyl methacrylate (MMA) and acrylate (such as butyl acrylate, ethyl acrylate) through emulsion polymerization. Acrylate processing aids can greatly improve the impact resistance and processing performance of PVC products and reduce the scrap rate in production.

[0004] However, although the addition of acrylic copolymer processing modifier can reduce the melt viscosity of polyvinyl chloride to a certain extent, improve the fluidity of polyvinyl chloride melt, and improve the processing and molding performance, it will affect the fracture toughness of polyvinyl chloride materials in low temperature environments, and cause the haze of polyvinyl chloride materials to increase to a certain extent, affecting transparency; at the same time, the addition of acrylic copolymer processing modifier will also significantly affect the processing torque and melt strength of polyvinyl chloride melt. There is a problem of sudden increase in processing torque during processing, which not only has poor processing stability, but also will cause residual stress inside the polyvinyl chloride product, resulting in poor thermal stability of the polyvinyl chloride product.

[0005] Therefore, a transparent PVC processing modifier and a preparation method thereof are provided, which can reduce the melt viscosity of polyvinyl chloride, improve the fluidity of polyvinyl chloride melt, improve the processing and molding performance, and at the same time improve the transparency and haze of polyvinyl chloride products and improve their fracture toughness in a low temperature environment; and avoid the adverse effects of the transparent PVC processing modifier on the polyvinyl chloride melt, adjust the stable processing torque, and improve the thermal stability of polyvinyl chloride products. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a transparent PVC processing modifier and a preparation method thereof, which can reduce the melt viscosity of polyvinyl chloride, improve the fluidity of polyvinyl chloride melt, improve the processing and molding performance, and at the same time improve the transparency and haze of polyvinyl chloride products, and improve their fracture toughness in a low temperature environment; and avoid the adverse effects of the transparent PVC processing modifier on the polyvinyl chloride melt, adjust the stable processing torque, and improve the thermal stability of the polyvinyl chloride products.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for preparing a transparent PVC processing modifier comprises the following steps: a first-stage reaction and a second-stage reaction; The first stage reaction comprises mixing deionized water, sodium dodecylbenzene sulfonate, methyl methacrylate, butyl acrylate, styrene and vinyl acetate uniformly, and then heating the mixture in an inert gas environment in the presence of an initiator to obtain a first stage reactant; The second-stage reaction comprises mixing the first-stage reactant, butyl methacrylate, acrylonitrile, isooctyl acrylate and the composite modifier uniformly, and then heating the mixture in an inert gas environment in the presence of an initiator to obtain the second-stage reactant; the second-stage reactant is spray-dried to obtain a transparent PVC processing modifier; The preparation method of the composite modifier comprises the following steps: preparing a hyperbranched modifier, and composite; The hyperbranched modifier is prepared by reacting hexadecyl dimethyl tertiary amine, N,N-dimethylethanolamine and epichlorohydrin to obtain a pre-reactant, and then heating the reaction in a solvent environment in the presence of a catalyst to obtain the hyperbranched modifier; The composite metal organic framework ZIF-8 is thermally activated, and then the activated ZIF-8 is mixed with a hyperbranched modifier and subjected to ultrasonic treatment to obtain a composite modifier.

[0008] Furthermore, in the first stage of the reaction, the reaction pressure is 0.1-0.12 MPa, the reaction temperature is 62-68° C., and the reaction time is 1-2 h; In the two-stage reaction, the reaction pressure is 0.1-0.12 MPa, the reaction temperature is 70-75° C., and the reaction time is 3-4 h.

[0009] Preferably, in the one-stage reaction, the weight ratio of deionized water, sodium dodecylbenzene sulfonate, methyl methacrylate, butyl acrylate, styrene, vinyl acetate and initiator is 100-105:0.9-1.1:35-37:8-8.3:5-5.2:1.5-1.6:0.3-0.35.

[0010] Furthermore, in the two-stage reaction, the weight ratio of the first-stage reactant, butyl methacrylate, acrylonitrile, isooctyl acrylate, composite modifier, and initiator is 100-105:50-53:16-17:7-8:7-7.5:0.4-0.45.

[0011] Furthermore, in the preparation of the hyperbranched modifier, hexadecyldimethyl tertiary amine and N,N-dimethylethanolamine are uniformly mixed, the temperature is raised to 80-85°C, and epichlorohydrin is added dropwise while maintaining the temperature; after the addition is completed, the mixture is stirred for 4-5 hours to remove unreacted epichlorohydrin to obtain a pre-reactant; the pre-reactant, anhydrous ethanol, and a catalyst are mixed, and the mixture is reacted at 80-85°C for 10-12 hours to obtain a hyperbranched modifier.

[0012] Preferably, in the preparation of the hyperbranched modifier, the molar amount of epichlorohydrin is 1.02-1.05 times the total molar amount of hexadecyldimethyl tertiary amine and N,N-dimethylethanolamine.

[0013] Preferably, in the preparation of the hyperbranched modifier, the weight ratio of the pre-reactant to anhydrous ethanol is 1:0.7-0.8; The added weight of the catalyst is 2-2.5% of the weight of the pre-reactant.

[0014] Preferably, in the compounding, the heat activation vacuum is 0.05-0.07MPa, the heat activation temperature is 150-160°C, and the heat activation time is 4-5h; The ultrasonic treatment temperature is 35-40°C, the ultrasonic treatment time is 30-50min, the ultrasonic frequency is 25-30KHz, and the ultrasonic power is 170-200W.

[0015] Preferably, in the composite, the weight ratio of activated ZIF-8 to hyperbranched modifier is 4.2-4.6:100.

[0016] A transparent PVC processing modifier is prepared by the above-mentioned preparation method.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The preparation method of the transparent PVC processing modifier of the present invention comprises the following steps: using methyl methacrylate, butyl acrylate, styrene and vinyl acetate as first-stage monomers for polymerization reaction to obtain a first-stage reactant; then using the first-stage reactant, a composite modifier and butyl methacrylate, acrylonitrile and isooctyl acrylate as second-stage monomers for polymerization reaction to obtain a second-stage reactant, and then spray drying to obtain a transparent PVC processing modifier; and in the preparation of the composite modifier, firstly using hexadecyl dimethyl tertiary amine and N,N-dimethylethanolamine to react with epichlorohydrin, the hexadecyl dimethyl tertiary amine providing a hydrophobic long chain as the hydrophobic end group of the hyperbranched modifier, and the N,N-dimethylethanolamine as a functionalized alkyl tertiary amine providing hydroxyl and tertiary amine groups to promote branching reaction and increase crosslinking density; the hexadecyl dimethyl tertiary amine and N,N-dimethylethanolamine are used as dual-active raw materials to react to prepare a hyperbranched modifier having multiple quaternary ammonium centers and a multi-branched network structure; and then The hyperbranched modifier is then compounded with the heat-activated ZIF-8, and a composite modifier is prepared through the electrostatic effect and adsorption effect of the two, thereby improving the compatibility of the hyperbranched modifier with the second-stage monomer and improving the reaction uniformity of the subsequent second-stage polymerization; in the second-stage reaction, the composite modifier uses the metal active node of ZIF-8 as an auxiliary initiation site to initiate the polymerization of the second-stage monomer, and participates in the cross-linking reaction of the second-stage monomer through the terminal group of the hyperbranched modifier in the composite modifier and the surface group of ZIF-8 to form a denser network structure to prepare a transparent PVC processing modifier; the aforementioned approximate means cooperate with each other and work synergistically, which can reduce the melt viscosity of polyvinyl chloride, improve the fluidity of polyvinyl chloride melt, improve the processing and molding performance, and at the same time improve the transparency and haze of polyvinyl chloride products, and improve their fracture toughness in a low-temperature environment; and avoid the adverse effects of the transparent PVC processing modifier on the polyvinyl chloride melt, adjust the stable processing torque, and improve the thermal stability of polyvinyl chloride products.

[0018] (2) The transparent PVC processing modifier of the present invention is used in the preparation of PVC products. The minimum torque of the PVC melt is 21.7-22.3 Nm, the maximum torque is 27.6-28.0 Nm, the equilibrium torque is 23.0-23.2 Nm, the melting factor is 0.88-0.91, and the fusion time is 125-132 s.

[0019] (3) The transparent PVC processing modifier of the present invention is used in the preparation of PVC products. The transparency of the prepared PVC products is 91.5-92.0%, the haze is 1.25-1.30%, and the notched impact strength is 37.4-37.7 KJ / m 2 , the tensile strength is 55.9-56.4MPa, and the flexural strength is 93.1-93.8MPa.

[0020] (4) The transparent PVC processing modifier of the present invention is used in the preparation of PVC products. The notched impact strength of the prepared PVC products after standing for 7 days in a temperature environment of -22°C is 37.0-37.4 KJ / m 2 .

[0021] (5) The transparent PVC processing modifier of the present invention is used in the preparation of PVC products. After the prepared PVC products are placed in an environment with a relative humidity of 90% and a temperature of 65°C for 21 days, the transparency is 91.1-91.6%, the haze is 1.27-1.32%, and the notched impact strength is 36.7-37.1 KJ / m 2 , the tensile strength is 55.1-55.7MPa, and the flexural strength is 91.5-92.3MPa. DETAILED DESCRIPTION

[0022] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described. It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the art to which the present invention belongs.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, "first", "second", etc. are used to distinguish similar objects, and are not used to describe a specific order or sequence. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0024] The embodiment of the present invention provides a method for preparing a transparent PVC processing modifier, which comprises the following steps: a first-stage reaction and a second-stage reaction.

[0025] The method for the one-stage reaction is as follows: deionized water and sodium dodecylbenzene sulfonate are added into a reactor, stirred for 5-10 minutes, and then methyl methacrylate, butyl acrylate, styrene and vinyl acetate are added, stirred at 180-220 rpm for 10-20 minutes, the air in the reactor is replaced by nitrogen, and the pressure in the reactor is adjusted to 0.1-0.12 MPa, and an initiator (preferably potassium persulfate) is added, and the temperature is raised to 62-68° C. with stirring at a stirring speed of 180-220 rpm, and the reaction is stirred and kept warm for 1-2 hours to obtain a first-stage reactant.

[0026] In the first-stage reaction, the weight ratio of deionized water, sodium dodecylbenzene sulfonate, methyl methacrylate, butyl acrylate, styrene, vinyl acetate and initiator is 100-105:0.9-1.1:35-37:8-8.3:5-5.2:1.5-1.6:0.3-0.35.

[0027] The method for the two-stage reaction is as follows: first-stage reactants, butyl methacrylate, acrylonitrile and isooctyl acrylate are added into a reactor, stirred at 220-250 rpm for 10-20 min, then a composite modifier is added, stirred for 10-20 min, the air in the reactor is replaced by nitrogen, the pressure in the reactor is adjusted to 0.1-0.12 MPa, an initiator (preferably potassium persulfate) is added, the temperature is raised to 70-75° C. at a stirring speed of 220-250 rpm, the reaction is stirred and kept warm for 3-4 h, and then cooled to obtain second-stage reactants; the second-stage reactants are spray-dried to obtain a transparent PVC processing modifier.

[0028] In the two-stage reaction, the weight ratio of the first-stage reactant, butyl methacrylate, acrylonitrile, isooctyl acrylate, composite modifier, and initiator is 100-105:50-53:16-17:7-8:7-7.5:0.4-0.45.

[0029] The preparation method of the composite modifier comprises the following steps: preparing a hyperbranched modifier and composite.

[0030] The method for preparing the hyperbranched modifier comprises the following steps: adding hexadecyldimethyl tertiary amine and N,N-dimethylethanolamine into a reaction kettle, stirring for 5-10 minutes, stirring and heating to 80-85°C, and keeping the temperature; then dripping epichlorohydrin at a dripping rate of 0.2-0.4 mL / min, and after the dripping of epichlorohydrin is completed, keeping the temperature and stirring for 4-5 hours, vacuum distilling and removing unreacted epichlorohydrin to obtain a pre-reactant; adding the pre-reactant and anhydrous ethanol into the reaction kettle, stirring for 15-30 minutes, and then continuously adding a catalyst (preferably triethylamine), stirring and heating to 80-85°C, keeping the temperature and reflux reaction for 10-12 hours, and obtaining the hyperbranched modifier.

[0031] In the preparation of the hyperbranched modifier, the molar amount of epichlorohydrin is 1.02-1.05 times the total molar amount of hexadecyldimethyl tertiary amine and N,N-dimethylethanolamine; The weight ratio of the pre-reactant to anhydrous ethanol is 1:0.7-0.8; The added weight of the catalyst is 2-2.5% of the weight of the pre-reactant.

[0032] The composite method comprises the following steps: placing the metal organic framework ZIF-8 in a vacuum oven, keeping the temperature at 150-160°C for activation for 4-5 hours in a vacuum environment of 0.05-0.07 MPa, and naturally cooling the temperature to room temperature to obtain activated ZIF-8; then adding the activated ZIF-8 into a hyperbranched modifier, heating the temperature to 35-40°C, keeping the temperature and ultrasonically treating the material for 30-50 minutes, and cooling the material to obtain a composite modifier.

[0033] In the compounding, the ultrasonic frequency of the ultrasonic treatment is 25-30KHz, and the ultrasonic power is 170-200W; The weight ratio of activated ZIF-8 to hyperbranched modifier is 4.2-4.6:100.

[0034] The embodiment of the present invention further provides a transparent PVC processing modifier, which is prepared by the above-mentioned preparation method.

[0035] The present invention is further described below in conjunction with some specific embodiments.

[0036] Example 1 This embodiment provides a method for preparing a transparent PVC processing modifier, specifically: 1. A reaction Deionized water and sodium dodecylbenzene sulfonate were added into the reactor. After stirring for 5 minutes, methyl methacrylate, butyl acrylate, styrene and vinyl acetate were added. The mixture was stirred at 180 rpm for 20 minutes. The air in the reactor was replaced with nitrogen. The pressure in the reactor was adjusted to 0.1 MPa. Potassium persulfate as an initiator was added. The mixture was heated to 62°C with stirring at 180 rpm. The mixture was stirred and reacted for 1.2 hours to obtain a first stage of reactants.

[0037] Among them, the weight ratio of deionized water, sodium dodecylbenzene sulfonate, methyl methacrylate, butyl acrylate, styrene, vinyl acetate and potassium persulfate is 100:1.01:35:8:5:1.5:0.3.

[0038] 2. Second stage reaction The first-stage reactant, butyl methacrylate, acrylonitrile and isooctyl acrylate are added into a reactor, stirred at 220 rpm for 20 min, and then the composite modifier is added. After stirring for 20 min, the air in the reactor is replaced by nitrogen, and the pressure in the reactor is adjusted to 0.1 MPa. Potassium persulfate as an initiator is added, and the temperature is raised to 70°C with stirring at a stirring speed of 220 rpm. After the reaction is stirred and kept warm for 3 h, the second-stage reactant is cooled to obtain the second-stage reactant. The second-stage reactant is spray-dried to obtain a transparent PVC processing modifier.

[0039] Wherein, the weight ratio of the first-stage reactant, butyl methacrylate, acrylonitrile, isooctyl acrylate, composite modifier and potassium persulfate is 100:50:16:7:7:0.4.

[0040] The preparation method of the composite modifier comprises the following steps: 1) Preparation of hyperbranched modifier Hexadecyldimethyl tertiary amine (0.7 mol) and N,N-dimethylethanolamine (0.2 mol) were added into the reactor, stirred for 5 min, then heated to 80°C with stirring and kept warm; then epichlorohydrin (0.92 mol) was added dropwise at a drop rate of 0.2 mL / min. After the addition of epichlorohydrin was completed, the mixture was kept warm and stirred for 4 h, and unreacted epichlorohydrin was removed by vacuum distillation to obtain a pre-reactant; the pre-reactant and anhydrous ethanol were added into the reactor, stirred for 15 min, and then the catalyst triethylamine was added, stirred and heated to 80°C, and kept warm for reflux reaction for 10 h to obtain a hyperbranched modifier.

[0041] Wherein, the weight ratio of the pre-reactant to anhydrous ethanol is 1:0.7.

[0042] The added weight of the catalyst triethylamine is 2% of the weight of the pre-reactant.

[0043] 2) Compound The metal organic framework ZIF-8 was placed in a vacuum oven, kept at 150°C for 4 hours in a vacuum environment of 0.05 MPa, and then naturally cooled to room temperature to obtain activated ZIF-8; then the activated ZIF-8 was put into a hyperbranched modifier, heated to 35°C, kept warm and ultrasonically treated for 30 minutes, and then cooled to obtain a composite modifier.

[0044] The ultrasonic frequency of the ultrasonic treatment is 25KHz, and the ultrasonic power is 170W.

[0045] The weight ratio of activated ZIF-8 to hyperbranched modifier is 4.2:100.

[0046] This embodiment also provides a transparent PVC processing modifier prepared by the above method, which has the appearance of white powder and an apparent density of 0.40 g / cm 3 .

[0047] Example 2 This embodiment provides a method for preparing a transparent PVC processing modifier, specifically: 1. A reaction Deionized water and sodium dodecylbenzenesulfonate were added into the reactor. After stirring for 8 minutes, methyl methacrylate, butyl acrylate, styrene and vinyl acetate were added. The mixture was stirred at 200 rpm for 15 minutes. The air in the reactor was replaced with nitrogen. The pressure in the reactor was adjusted to 0.11 MPa. Potassium persulfate as an initiator was added. The mixture was heated to 65°C with stirring at a stirring speed of 200 rpm. The mixture was stirred and reacted for 1.5 hours to obtain a first stage of reactants.

[0048] Among them, the weight ratio of deionized water, sodium dodecylbenzene sulfonate, methyl methacrylate, butyl acrylate, styrene, vinyl acetate and potassium persulfate is 102:1.05:36:8.2:5.1:1.55:0.34.

[0049] 2. Second stage reaction The first-stage reactant, butyl methacrylate, acrylonitrile and isooctyl acrylate are added into a reactor. After stirring at 230 rpm for 15 minutes, the composite modifier is continuously added. After stirring for 15 minutes, the air in the reactor is replaced by nitrogen, and the pressure in the reactor is adjusted to 0.11 MPa. Potassium persulfate as an initiator is added. At a stirring speed of 230 rpm, the temperature is raised to 72°C with stirring. After the reaction is stirred and kept warm for 3.5 hours, the second-stage reactant is cooled to obtain the second-stage reactant. The second-stage reactant is spray-dried to obtain a transparent PVC processing modifier.

[0050] Among them, the weight ratio of the first-stage reactant, butyl methacrylate, acrylonitrile, isooctyl acrylate, composite modifier and potassium persulfate is 102:51:16.4:7.5:7.3:0.42.

[0051] The preparation method of the composite modifier comprises the following steps: 1) Preparation of hyperbranched modifier Hexadecyldimethyl tertiary amine (0.8 mol) and N,N-dimethylethanolamine (0.2 mol) were added into the reactor, stirred for 8 min, heated to 83°C with stirring, and kept warm; then, epichlorohydrin (1.03 mol) was added dropwise at a drop rate of 0.3 mL / min. After the addition of epichlorohydrin was completed, the mixture was kept warm and stirred for 4.5 h, and unreacted epichlorohydrin was removed by vacuum distillation to obtain a pre-reactant; the pre-reactant and anhydrous ethanol were added into the reactor, stirred for 20 min, and then the catalyst triethylamine was added, stirred and heated to 82°C, and kept warm for reflux reaction for 11 h to obtain a hyperbranched modifier.

[0052] Wherein, the weight ratio of the pre-reactant to anhydrous ethanol is 1:0.75.

[0053] The added weight of the catalyst triethylamine is 2.3% of the weight of the pre-reactant.

[0054] 2) Compound The metal organic framework ZIF-8 was placed in a vacuum oven, kept at 155°C for activation for 4.5 hours in a vacuum environment of 0.06 MPa, and then naturally cooled to room temperature to obtain activated ZIF-8; then the activated ZIF-8 was put into a hyperbranched modifier, heated to 38°C, kept warm and ultrasonically treated for 40 minutes, and then cooled to obtain a composite modifier.

[0055] The ultrasonic frequency of the ultrasonic treatment is 28KHz, and the ultrasonic power is 180W.

[0056] The weight ratio of activated ZIF-8 to hyperbranched modifier is 4.5:100.

[0057] This embodiment also provides a transparent PVC processing modifier prepared by the above method, which has the appearance of white powder and an apparent density of 0.42 g / cm 3 .

[0058] Example 3 This embodiment provides a method for preparing a transparent PVC processing modifier, specifically: 1. A reaction Deionized water and sodium dodecylbenzene sulfonate were added into the reactor. After stirring for 10 minutes, methyl methacrylate, butyl acrylate, styrene and vinyl acetate were added. The mixture was stirred at 220 rpm for 10 minutes. The air in the reactor was replaced with nitrogen. The pressure in the reactor was adjusted to 0.12 MPa. Potassium persulfate as an initiator was added. The mixture was heated to 68°C with stirring at a stirring speed of 220 rpm. The mixture was stirred and reacted for 2 hours to obtain a first stage of reactants.

[0059] Wherein, the weight ratio of deionized water, sodium dodecylbenzene sulfonate, methyl methacrylate, butyl acrylate, styrene, vinyl acetate and potassium persulfate is 105:1.1:37:8.3:5.2:1.6:0.35.

[0060] 2. Second stage reaction The first-stage reactant, butyl methacrylate, acrylonitrile and isooctyl acrylate are added into a reactor, stirred at 250 rpm for 10 min, and then the composite modifier is added. After stirring for 10 min, the air in the reactor is replaced by nitrogen, and the pressure in the reactor is adjusted to 0.12 MPa. Potassium persulfate as an initiator is added, and the temperature is raised to 75°C with stirring at a stirring speed of 250 rpm. After the reaction is stirred and kept warm for 4 hours, the second-stage reactant is cooled to obtain the second-stage reactant. The second-stage reactant is spray-dried to obtain a transparent PVC processing modifier.

[0061] Wherein, the weight ratio of the first-stage reactant, butyl methacrylate, acrylonitrile, isooctyl acrylate, composite modifier and potassium persulfate is 105:53:17:8:7.5:0.45.

[0062] The preparation method of the composite modifier comprises the following steps: 1) Preparation of hyperbranched modifier Hexadecyldimethyl tertiary amine (0.8 mol) and N,N-dimethylethanolamine (0.25 mol) were added into the reactor, stirred for 10 min, then heated to 85°C with stirring and kept warm; then epichlorohydrin (1.1 mol) was added dropwise at a drop rate of 0.4 mL / min, and after the addition of epichlorohydrin was completed, the mixture was kept warm and stirred for 5 h, and unreacted epichlorohydrin was removed by vacuum distillation to obtain a pre-reactant; the pre-reactant and anhydrous ethanol were added into the reactor, stirred for 30 min, and then the catalyst triethylamine was added, stirred and heated to 85°C, and kept warm and refluxed for 12 h to obtain a hyperbranched modifier.

[0063] Wherein, the weight ratio of the pre-reactant to anhydrous ethanol is 1:0.8.

[0064] The added weight of the catalyst triethylamine is 2.5% of the weight of the pre-reactant.

[0065] 2) Compound The metal organic framework ZIF-8 was placed in a vacuum oven, kept at 160°C for activation for 5 hours in a vacuum environment of 0.07 MPa, and then naturally cooled to room temperature to obtain activated ZIF-8; then the activated ZIF-8 was put into a hyperbranched modifier, heated to 40°C, kept warm and ultrasonically treated for 50 minutes, and then cooled to obtain a composite modifier.

[0066] The ultrasonic frequency of the ultrasonic treatment is 30KHz, and the ultrasonic power is 200W.

[0067] The weight ratio of activated ZIF-8 to hyperbranched modifier is 4.6:100.

[0068] This embodiment also provides a transparent PVC processing modifier prepared by the above method, which has the appearance of white powder and an apparent density of 0.43 g / cm 3 .

[0069] Comparative Example 1 For ease of comparison, Comparative Example 1 adopts the technical solution of Example 2, and the changes made thereon are in the preparation of the composite modifier used in the second-stage reaction process: 1) the addition of N,N-dimethylethanolamine is omitted; 2) the addition of the metal organic framework ZIF-8 is omitted, and the hyperbranched modifier is directly used in the second-stage reaction instead of the composite modifier in an equal amount.

[0070] Comparative Example 2 For ease of comparison, Comparative Example 2 adopts the technical solution of Example 2, and the change made thereon is in the preparation of the composite modifier used in the second-stage reaction process: the preparation of the hyperbranched modifier is omitted, and hexadecyltrimethylammonium chloride is used instead of the hyperbranched modifier to be compounded with ZIF-8 to prepare the composite modifier.

[0071] The transparent PVC processing modifiers of Examples 1-3 and Comparative Examples 1-2 were respectively used in the preparation of PVC materials. Specifically, the following raw materials for preparing PVC materials were prepared by weight: 100 parts of PVC, 5 parts of calcium carbonate, 3.75 parts of calcium zinc stabilizer, 0.2 parts of stearic acid, 1.5 parts of titanium dioxide, 0.15 parts of oxidized polyethylene wax, and 5 parts of transparent PVC processing modifier; the raw materials were melted and mixed uniformly; and the minimum torque, maximum torque, equilibrium torque, melting factor, and fusion time of the PVC melt were detected by a Haake torque rheometer, and the specific results are shown in the following table:

[0072] Further, the above raw materials were melted and mixed uniformly, and then plasticized and vulcanized to prepare standard test samples. The transparency, haze, notched impact strength, tensile strength and flexural strength of each sample were tested at room temperature. The test methods of transparency and haze refer to the standard GB / T 2410-2008 "Determination of light transmittance and haze of transparent plastics"; the test method of notched impact strength refers to the standard GB / T 1043.1-2008 "Determination of impact properties of simply supported beams of plastics Part 1: Non-instrumented impact test"; the test method of tensile strength refers to GB / T 1040.1-2008 "Determination of tensile properties of plastics"; the test method of flexural strength refers to GB / T 9341-2008 "Determination of flexural properties of plastics"; the specific results are shown in the following table:

[0073] Furthermore, each sample was placed in a low temperature environment of -22°C. After standing for 7 days, the notched impact strength of each sample at -22°C was tested. The specific results are shown in the following table:

[0074] Furthermore, each sample was placed in a high humidity and heat environment with a relative humidity of 90% and a temperature of 65°C. After standing for 21 days, the transparency, haze, notched impact strength, tensile strength and flexural strength of each sample were tested. The specific results are shown in the following table:

[0075] It can be seen that the preparation method of the transparent PVC processing modifier of the present invention uses methyl methacrylate, butyl acrylate, styrene, and vinyl acetate as first-stage monomers for polymerization reaction to obtain a first-stage reactant; then the first-stage reactant, the composite modifier and butyl methacrylate, acrylonitrile, and isooctyl acrylate as second-stage monomers are polymerized to obtain a second-stage reactant, which is then spray-dried to obtain a transparent PVC processing modifier; and in the preparation of the composite modifier, hexadecyl dimethyl tertiary amine and N,N-dimethylethanolamine are first used to react with epichlorohydrin, and the hexadecyl dimethyl tertiary amine provides a hydrophobic long chain as the hydrophobic end group of the hyperbranched modifier, and N,N-dimethylethanolamine is used as a functionalized alkyl tertiary amine to provide hydroxyl and tertiary amine groups to promote the branching reaction. The invention discloses a novel polyvinyl chloride (PVC) processing method for PVC film, wherein the polyvinyl chloride (PVC) is reacted with the polyvinyl chloride (PVC) to form a polyvinyl chloride (PVC) polymer. The polyvinyl chloride (PVC) is reacted with the polyvinyl chloride (PVC) polymer to form a polyvinyl chloride (PVC) polymer. The polyvinyl chloride (PVC) is reacted with the polyvinyl chloride (PVC) polymer to form a polyvinyl chloride (PVC) polymer. The polyvinyl chloride (PVC) is reacted with the polyvinyl chloride (PVC) polymer to form a polyvinyl chloride (PVC) polymer. The polyvinyl chloride (PVC) is reacted with the polyvinyl chloride (PVC) polymer to form a polyvinyl chloride (PVC) polymer. The polyvinyl chloride (PVC) is reacted with the polyvinyl chloride (PVC) polymer to form a polyvinyl chloride (PVC) polymer. The polyvinyl chloride (PVC) is reacted with the polyvinyl chloride (PVC) polymer to form a polyvinyl chloride (PVC) polymer. The polyvinyl chloride (PVC) is reacted with the polyvinyl chloride (PVC) polymer to form a polyvinyl chloride (PVC) polymer.

[0076] In the preparation of PVC materials, the hyperbranched modifier component of the composite modifier in the added transparent PVC processing modifier is used to reduce the entanglement and friction of molecular chains in the polyvinyl chloride melt, improve the fluidity of the polyvinyl chloride melt, adjust and stabilize the melt processing torque, reduce the large fluctuation of the processing torque, promote the uniform plasticization of polyvinyl chloride particles, increase the melting factor, and improve its processing performance; at the same time, the tertiary amine group of the hyperbranched modifier is used to capture HCl released by the decomposition of polyvinyl chloride in a high temperature environment, reduce the self-catalytic decomposition effect of HCl on polyvinyl chloride, and improve its thermal stability; and the network structure of the hyperbranched modifier is used as an elastic node and dispersed in the PVC matrix to improve the toughness and impact resistance of the polyvinyl chloride product, especially its low-temperature toughness. Furthermore, through the porous adsorption effect of the metal organic framework ZIF-8 in the composite modifier, the free plasticizer in the polyvinyl chloride and the HCl released by decomposition in a high temperature environment are captured, the viscosity fluctuation during the processing is reduced, the melt processing torque is adjusted and stabilized, and the thermal stability is improved; at the same time, through its dispersing effect as a filler, the molecular chain slip is hindered, the low-temperature migration of the plasticizer is delayed, and the low-temperature toughness is improved; and through its own thermal barrier effect, the thermal stability of polyvinyl chloride products is further improved.

[0077] Comparative Example 1: After omitting the addition of N,N-dimethylethanolamine and metal organic framework ZIF-8 in the preparation of the composite modifier, it is impossible to prepare a hyperbranched modifier with multiple quaternary ammonium centers and a multi-branch network structure by combining N,N-dimethylethanolamine with hexadecyl dimethyl tertiary amine, and it is impossible to effectively achieve its improvement effect on polyvinyl chloride; nor can it further enhance the thermal stability, processing performance, and low-temperature toughness of polyvinyl chloride by combining metal organic framework ZIF-8. Specifically, the fluctuation of the processing torque of the PVC melt increases and the melting factor decreases; the toughness and mechanical properties of the prepared PVC products are significantly reduced; at the same time, the toughness of the PVC products in a low temperature environment is significantly reduced; and the thermal stability of the PVC products is reduced, and after standing for a long time in a high humidity and heat environment, its toughness and mechanical properties are significantly reduced.

[0078] In Comparative Example 2, the preparation of the hyperbranched modifier is omitted in the preparation of the composite modifier. After cetyltrimethylammonium chloride is used instead of the hyperbranched modifier and composited with ZIF-8 to prepare the composite modifier, the hyperbranched modifier cannot be used to effectively improve the processing performance of the PVC melt and the related performance of the PVC products; specifically, the processing performance indicators such as the fluctuation of the processing torque and the melting factor of the PVC melt are deteriorated to a certain extent, and the toughness and mechanical properties of the prepared PVC products are reduced to a certain extent; at the same time, the toughness of the PVC products in a low temperature environment is reduced to a certain extent; and the thermal stability of the PVC products is reduced. After standing for a long time in a high humidity and heat environment, the toughness and mechanical properties are reduced to a certain extent.

[0079] Unless otherwise specified, all percentages used in the present invention are by mass.

[0080] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a transparent PVC processing modifier, characterized in that: The method comprises the following steps: a first-stage reaction and a second-stage reaction; The first stage reaction comprises mixing deionized water, sodium dodecylbenzene sulfonate, methyl methacrylate, butyl acrylate, styrene and vinyl acetate uniformly, and then heating the mixture in an inert gas environment in the presence of an initiator to obtain a first stage reactant; The second-stage reaction comprises mixing the first-stage reactant, butyl methacrylate, acrylonitrile, isooctyl acrylate and the composite modifier uniformly, and then heating the mixture in an inert gas environment in the presence of an initiator to obtain the second-stage reactant; the second-stage reactant is spray-dried to obtain a transparent PVC processing modifier; The preparation method of the composite modifier comprises the following steps: preparing a hyperbranched modifier, and composite; The hyperbranched modifier is prepared by reacting hexadecyl dimethyl tertiary amine, N,N-dimethylethanolamine and epichlorohydrin to obtain a pre-reactant, and then heating the reaction in a solvent environment in the presence of a catalyst to obtain the hyperbranched modifier; The composite metal organic framework ZIF-8 is thermally activated, and then the activated ZIF-8 is mixed with a hyperbranched modifier and subjected to ultrasonic treatment to obtain a composite modifier.

2. The method for preparing the transparent PVC processing modifier according to claim 1, characterized in that: In the first stage reaction, the reaction pressure is 0.1-0.12MPa, the reaction temperature is 62-68°C, and the reaction time is 1-2h; In the two-stage reaction, the reaction pressure is 0.1-0.12 MPa, the reaction temperature is 70-75° C., and the reaction time is 3-4 h.

3. The method for preparing the transparent PVC processing modifier according to claim 1, characterized in that: In the first-stage reaction, the weight ratio of deionized water, sodium dodecylbenzene sulfonate, methyl methacrylate, butyl acrylate, styrene, vinyl acetate and initiator is 100-105:0.9-1.1:35-37:8-8.3:5-5.2:1.5-1.6:0.3-0.

35.

4. The method for preparing the transparent PVC processing modifier according to claim 1, characterized in that: In the two-stage reaction, the weight ratio of the first-stage reactant, butyl methacrylate, acrylonitrile, isooctyl acrylate, composite modifier, and initiator is 100-105:50-53:16-17:7-8:7-7.5:0.4-0.

45.

5. The method for preparing the transparent PVC processing modifier according to claim 1, characterized in that: The method for preparing the hyperbranched modifier comprises the following steps: uniformly mixing hexadecyldimethyl tertiary amine and N,N-dimethylethanolamine, heating the mixture to 80-85° C., and dripping epichlorohydrin while keeping the temperature high; after the dripping is completed, stirring the mixture while keeping the temperature high for 4-5 hours, removing unreacted epichlorohydrin, and obtaining a pre-reactant; mixing the pre-reactant, anhydrous ethanol, and a catalyst, and reacting the mixture at 80-85° C. while keeping the temperature high for 10-12 hours, thereby obtaining the hyperbranched modifier.

6. The method for preparing the transparent PVC processing modifier according to claim 1, characterized in that: In the preparation of the hyperbranched modifier, the molar amount of epichlorohydrin is 1.02-1.05 times the total molar amount of hexadecyldimethyl tertiary amine and N,N-dimethylethanolamine.

7. The method for preparing the transparent PVC processing modifier according to claim 5, characterized in that: In the preparation of the hyperbranched modifier, the weight ratio of the pre-reactant to anhydrous ethanol is 1:0.7-0.8; The added weight of the catalyst is 2-2.5% of the weight of the pre-reactant.

8. The method for preparing the transparent PVC processing modifier according to claim 1, characterized in that: In the compounding, the heat activation vacuum is 0.05-0.07MPa, the heat activation temperature is 150-160°C, and the heat activation time is 4-5h; The ultrasonic treatment temperature is 35-40°C, the ultrasonic treatment time is 30-50min, the ultrasonic frequency is 25-30KHz, and the ultrasonic power is 170-200W.

9. The method for preparing the transparent PVC processing modifier according to claim 1, characterized in that: In the composite, the weight ratio of activated ZIF-8 to hyperbranched modifier is 4.2-4.6:

100.

10. A transparent PVC processing modifier, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

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