Preparation method and application of acrylic ester PVC impact modifier

Abstract

This application relates to the field of polymer materials technology and specifically discloses a method for preparing an acrylic ester PVC impact modifier and its application. The method comprises the following steps: first, preparing a binder and a composite hydroxyl-terminated hyperbranched polyester, and then sequentially adding the binder and the composite hydroxyl-terminated hyperbranched polyester to the core layer emulsion and the shell layer structure to obtain the acrylic ester PVC impact modifier. The acrylic ester PVC impact modifier prepared by this method exhibits high impact resistance and high toughness.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and more specifically, to a preparation method of an acrylic ester PVC impact modifier and its application. Background Art

[0002] As one of the five most common plastics, polyvinyl chloride (PVC) is widely used in construction, packaging, electronics, and other fields due to its excellent cost-effectiveness and comprehensive performance. However, the inherent brittleness of PVC, particularly the sharp decline in impact resistance at low temperatures, has severely restricted its application in engineering. To overcome this technical bottleneck, the development of impact modifiers has become a key research direction in PVC modification.

[0003] Acrylic impact modifiers have become the preferred option for modifying rigid PVC due to their excellent compatibility with PVC and significant toughening effects. Traditional acrylate impact modifiers utilize a core-shell structure, where an elastic core absorbs impact energy while a rigid shell maintains material strength and maintains uniform dispersion of the impact modifier within the PVC. However, this simple core-shell structure suffers from weak interfacial bonding and limited toughening efficiency, making it difficult to meet the stringent material performance requirements of high-end applications.

[0004] Chinese patent application publication number CN104231151A discloses a large-particle acrylic impact modifier for polyvinyl chloride (PVC) and its preparation method. The impact modifier is a large-particle, core-shell polyacrylate copolymer. This invention utilizes a seed emulsion polymerization process with polyvinyl alcohol as a protective colloid to synthesize a seed emulsion with a core layer composed of butyl acrylate, isobornyl methacrylate, methyl methacrylate, and a crosslinker, and a shell layer composed of butyl acrylate, styrene, isobornyl methacrylate, methyl methacrylate, and a crosslinker. The grafted copolymer produced in this invention has a particle size greater than 600 nm, allowing the acrylic impact modifier to be quickly and evenly dispersed in the PVC particles, thereby toughening the PVC product.

[0005] In the above documents, the bonding force between the core layer and the shell layer of the prepared acrylic impact modifier is low. During the production process of polyvinyl chloride products, core-shell separation is easily caused by high shear stress, which leads to the inability of the modified polyvinyl chloride products to quickly and effectively transmit and disperse stress during use, and the modified polyvinyl chloride products are prone to cracks. Summary of the Invention

[0006] In order to further improve the bonding strength and impact resistance between the core and shell of the acrylic ester PVC impact modifier, thereby making the modified polyvinyl chloride have higher toughness, the present application provides a preparation method of the acrylic ester PVC impact modifier and its application.

[0007] In a first aspect, the present application provides a method for preparing an acrylic ester PVC impact modifier, using the following technical solution:

[0008] A method for preparing an acrylic ester PVC impact modifier comprises the following steps:

[0009] 1) aminoethanol, acrylate, hydroquinone and tetrabutyl titanate are mixed and polymerized to obtain a binder;

[0010] 2) mixing deionized water, butyl acrylate, divinylbenzene, sodium lauryl sulfate, potassium persulfate and a binder, and performing a cross-linking polymerization reaction to obtain a core layer emulsion;

[0011] 3) mixing the core layer emulsion, deionized water, sodium lauryl sulfate, potassium persulfate, methyl methacrylate, and the composite hydroxyl-terminated hyperbranched polyester, performing a polymerization reaction, adding calcium chloride to break the emulsion, and centrifugally drying to obtain an acrylic ester PVC impact modifier;

[0012] The preparation method of the composite hydroxyl-terminated hyperbranched polyester comprises the following steps: mixing hydroxymethyl carboxylic acid, polyol, p-toluenesulfonic acid, nanocellulose and dihydroxymethyl propionic acid, and performing hyperbranched polymerization reaction to obtain the composite hydroxyl-terminated hyperbranched polyester.

[0013] By adopting the above technical solution, during the preparation process of the impact modifier, a binder is added to strengthen the core-shell structure characteristics. The polar and non-polar parts of the binder improve the core-shell interface compatibility, thereby enhancing the binding force between the core and the shell, effectively avoiding the core-shell separation when the impact modifier is subjected to external force impact, thereby causing a decrease in the toughening effect; the addition of the composite end-hydroxy hyperbranched polyester makes the shell structure denser, reduces the occurrence of shell cracks, and thus enables the impact modifier to have good dispersibility in the polyvinyl chloride matrix, forming a uniform stress dispersion network structure, and improving the toughness of the polyvinyl chloride; at the same time, the amino groups in the binder and the hydroxyl groups in the composite end-hydroxy hyperbranched polyester form a dynamic hydrogen bond network, which can be broken and reorganized under the action of stress, effectively dissipates energy when subjected to external impact, and improves the impact toughness of the impact modifier.

[0014] Preferably, in step 1), the specific operation of the polymerization reaction includes the following steps: uniformly mixing aminoethanol and acrylate, heating to 60-90°C, adding hydroquinone and tetrabutyl titanate, reacting for 2-4 hours, then heating to 100-110°C, reacting for 5-7 hours to obtain a binder.

[0015] Preferably, in step 2), the specific operation of the cross-linking polymerization reaction comprises the following steps: uniformly mixing deionized water, butyl acrylate, divinylbenzene, and sodium lauryl sulfate, passing nitrogen, heating, adding potassium persulfate, reacting for 2-3 hours, then adding a mixed solution of potassium persulfate, butyl acrylate, binder, and divinylbenzene in a mass ratio of (0.05-0.1):(1.2-1.6):1:(0.05-0.1), and continuing the reaction for 2-3 hours to obtain a core layer emulsion.

[0016] Preferably, in step 3), the specific operation of the polymerization reaction includes the following steps: uniformly mixing the core layer emulsion, deionized water, sodium lauryl sulfate and potassium persulfate, passing nitrogen, heating, then adding a mixed solution of methyl methacrylate and composite terminal hydroxyl hyperbranched polyester, reacting for 1.5-3 hours, adding calcium chloride to break the emulsion, centrifuging, and drying to obtain an acrylic ester PVC impact modifier.

[0017] Preferably, the specific operation of the hyperbranched polymerization reaction includes the following steps: uniformly mixing hydroxymethyl carboxylic acid and polyol, passing nitrogen, heating to 130-140° C., sequentially adding p-toluenesulfonic acid, nanocellulose, dihydroxymethylpropionic acid and p-toluenesulfonic acid, stopping the nitrogen flow after the reaction, keeping the temperature constant, performing vacuum rotary evaporation for 2-3 hours, and cooling to room temperature to obtain a composite terminal hydroxyl hyperbranched polyester.

[0018] Preferably, the method for preparing nanocellulose comprises the following steps: crushing natural cellulose to obtain cellulose powder, mixing the cellulose powder with sulfuric acid, stirring and reacting, washing after the reaction to obtain a nanocellulose suspension, ultrasonically treating the nanocellulose suspension, and freeze-drying to obtain nanocellulose.

[0019] By adopting the above technical solution, the size of nanocellulose is reduced, its specific surface area is increased, the contact area between nanocellulose and terminal hydroxyl hyperbranched polyester is increased, the interface bonding is tighter, and the stress transfer is more effective, thereby improving the strength and toughness of the impact modifier.

[0020] Preferably, in step 1), the aminoethanol is one of methylethanolamine, dimethylaminoethanol and monoethanolamine; and the acrylate is one of methyl acrylate, ethyl acrylate and butyl acrylate.

[0021] By adopting the above technical solution, aminoethanol and acrylate with moderate activity are selected during the preparation process of the binder, which ensures that the reaction can proceed smoothly while avoiding the problem of excessively violent reaction that is difficult to control, and reduces the generation of by-products. The prepared binder forms a chemical bond with the core-shell material at the core-shell interface, thereby enhancing the stability of the interface. When the material is impacted, the impact modifier effectively transfers and dissipates the impact energy between the core and the shell and in the entire material system, thereby improving the impact toughness of the material.

[0022] Preferably, in step 1), the mass ratio of aminoethanol to acrylate is 1:(1.4-3.5).

[0023] By adopting the above technical solution, during the reaction process, aminoethanol and acrylate are fully contacted, the reaction conversion rate is improved, and at the same time, the molecular structure of the prepared binder is ensured to be regular, and it is more tightly combined with the shell layer to form a stable interface transition layer, thereby optimizing the transfer of stress between the core and the shell, and fully exerting the toughening effect of the impact modifier.

[0024] Preferably, in step 3), the mass ratio of methyl methacrylate to the composite hydroxyl-terminated hyperbranched polyester is 1:(0.08-0.25).

[0025] By adopting the above technical solution, the terminal hydroxyl hyperbranched polyester can interact well with methyl methacrylate. The composite terminal hydroxyl hyperbranched polyester has a highly branched structure and a large number of hydroxyl groups. When it participates in the polymerization reaction of methyl methacrylate, the crosslinking density of the shell is appropriately increased, thereby enhancing the mechanical properties of the shell, while reducing the presence of shell cracks, increasing the wear resistance of the impact modifier and the dispersibility of the impact modifier in the polyvinyl chloride matrix.

[0026] Preferably, the hydroxymethyl carboxylic acid is one of dimethylol propionic acid, dimethylol butyric acid and dimethylol acetic acid; and the polyol is one of glycerol, trimethylol propane and pentaerythritol.

[0027] By adopting the above technical solution, the composite terminal hydroxyl hyperbranched polyester prepared has a certain flexibility. When it is used in the shell layer, the flexibility of the shell layer is improved, the shell layer is prevented from being too rigid, and the impact resistance and toughness of the impact modifier are thereby improved.

[0028] Preferably, the mass ratio of the hydroxymethylcarboxylic acid, the polyol and the nanocellulose is (1.1-3.3):1:(0.02-0.06).

[0029] The adoption of the above technical solution is conducive to improving the structural uniformity and stability of the composite terminal hydroxyl hyperbranched polyester. At the same time, the nanocellulose is evenly dispersed in the system and fully contacts the active groups in the reaction system, so that the nanocellulose and the terminal hydroxyl hyperbranched polyester are tightly combined, effectively bearing and transmitting external forces, so that the material can more effectively resist deformation and damage when subjected to external forces, thereby improving the hardness, toughness and tensile strength of the impact modifier.

[0030] Preferably, the ultrasonic treatment is performed at a power of 200-300 W and for a time of 30-60 min.

[0031] By adopting the above technical solution, the fiber bundles of nanocellulose are effectively dispersed and refined. Under the action of ultrasound, tiny cavitation bubbles are generated on the surface and inside of the nanocellulose. The impact force and shear force generated when the cavitation bubbles burst break the hydrogen bonds and van der Waals forces between the fibers, causing the fiber bundles to depolymerize into smaller fibers, increasing their specific surface area, thereby improving the dispersibility and compatibility of nanocellulose in the terminal hydroxyl hyperbranched polyester, and further improving the stability of the composite terminal hydroxyl hyperbranched polyester, which is conducive to consuming more stress and achieving a better toughening effect of the impact modifier.

[0032] In a second aspect, the present invention provides an acrylic ester PVC impact modifier prepared by the above preparation method.

[0033] In a third aspect, the present invention provides a use of the above-mentioned acrylic ester PVC impact modifier as a toughening agent in polyvinyl chloride plastics.

[0034] In summary, this application has the following beneficial effects:

[0035] 1. By using aminoethanol to react with acrylate to generate a binder with polar groups, the interfacial bonding between the core layer and the shell layer is enhanced, phase separation is reduced, and stress transfer efficiency is improved, thereby making the impact modifier have a good toughening effect.

[0036] 2. Nanocellulose has a high modulus and large specific surface area, forming a rigid network within the hydroxyl-terminated hyperbranched polyester. This limits molecular chain slippage and improves the tensile strength of the composite hydroxyl-terminated hyperbranched polyester, effectively dispersing stress and inhibiting crack propagation, enabling the impact modifier to achieve a better toughening effect in PVC. Furthermore, during the formation of the impact modifier shell, the polyhydroxy structure of the composite hydroxyl-terminated hyperbranched polyester forms a physical crosslinking network with the matrix polymethyl methacrylate, fully filling the shell interface defects and ensuring the integrity of the shell, thereby ensuring good dispersibility of the impact modifier in PVC.

[0037] 3. The amino groups in the binder and the hydroxyl groups in the composite terminal hydroxyl hyperbranched polyester form a dynamic hydrogen bond network, which can be broken and reorganized under stress, effectively dissipating energy when subjected to external impact, thereby improving the impact toughness of the impact modifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the tensile properties of modified polyvinyl chloride prepared using the acrylic ester PVC impact modifiers of Examples 1-3 and Comparative Examples 1-2 of the present application.

[0039] Figure 2 It is a schematic diagram of the impact resistance of modified polyvinyl chloride prepared by using the acrylic ester PVC impact modifiers of Examples 1-3 and Comparative Examples 1-2 of the present application. DETAILED DESCRIPTION

[0040] The present application is further described in detail below with reference to the embodiments.

[0041] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present application are all commercially available.

[0042] Example 1

[0043] The preparation steps of the acrylic ester PVC impact modifier of this embodiment are as follows:

[0044] 1) Mix 50g of monoethanolamine and 70g of methyl acrylate, heat to 60°C, add 0.5g of hydroquinone and 2g of tetrabutyl titanate, react for 4h, then heat to 110°C and react for 5h to obtain a binder;

[0045] 2) 50 g of deionized water, 55 g of butyl acrylate, 0.4 g of divinylbenzene, and 0.6 g of sodium lauryl sulfate were mixed uniformly, purged with nitrogen, and heated to 75°C. 0.3 g of potassium persulfate was added and reacted for 2 h. A mixed solution consisting of 0.5 g of potassium persulfate, 12 g of butyl acrylate, 10 g of a binder, and 0.5 g of divinylbenzene was added at a rate of 0.2 g / min and the reaction was continued for 2 h to obtain a core layer emulsion;

[0046] 3) 75 g of the core layer emulsion, 80 g of deionized water, 1.2 g of sodium lauryl sulfate, and 0.5 g of potassium persulfate were mixed evenly, purged with nitrogen, and heated to 80°C. A mixed solution of 25 g of methyl methacrylate and 5 g of a composite end-hydroxyl hyperbranched polyester was added at a rate of 0.3 g / min. The mixture was reacted for 1.5 h, and 1.8 g of calcium chloride was added to break the emulsion. The mixture was centrifuged and dried to obtain an acrylic PVC impact modifier.

[0047] The preparation method of the composite hydroxyl-terminated hyperbranched polyester of this embodiment includes the following steps: 33 g of dihydroxymethylbutyric acid and 30 g of propylene glycol are uniformly mixed, nitrogen is passed through, the temperature is raised to 130° C., 0.7 g of p-toluenesulfonic acid is added, and the reaction is carried out for 1 hour, 0.6 g of nanocellulose is added, and the reaction is carried out for 1 hour, 8 g of dihydroxymethylpropionic acid and 1 g of p-toluenesulfonic acid are added, and the reaction is continued for 3 hours. After the reaction is completed, the nitrogen is stopped, the temperature is maintained unchanged, and the composite hydroxyl-terminated hyperbranched polyester is obtained by vacuum rotary evaporation for 2 hours, and then cooled to room temperature to obtain the composite hydroxyl-terminated hyperbranched polyester.

[0048] The preparation method of nanocellulose in this embodiment is as follows: 10g of natural cellulose is crushed, washed, and dried to obtain cellulose powder, and then the cellulose powder is evenly mixed with 80g of sulfuric acid with a mass percentage concentration of 64%, the temperature is adjusted to 45°C, and the reaction is carried out for 2h. After the reaction is completed, it is centrifuged and washed with deionized water until neutral, and finally washed with ethanol to obtain a nanocellulose suspension. The nanocellulose suspension is then ultrasonically treated at a power of 200W for 60 minutes, and freeze-dried to obtain nanocellulose.

[0049] Example 2

[0050] The preparation steps of the acrylic ester PVC impact modifier of this embodiment are as follows:

[0051] 1) Mix 50g of methylethanolamine and 175g of butyl acrylate, heat to 90°C, add 0.7g of hydroquinone and 3g of tetrabutyl titanate, react for 2h, then heat to 100°C and react for 7h to obtain a binder;

[0052] 2) 80 g of deionized water, 70 g of butyl acrylate, 0.6 g of divinylbenzene, and 1 g of sodium lauryl sulfate were mixed uniformly, purged with nitrogen, and heated to 80°C. 0.5 g of potassium persulfate was added and reacted for 3 h. A mixed solution consisting of 1 g of potassium persulfate, 16 g of butyl acrylate, 10 g of a binder, and 1 g of divinylbenzene was added at a rate of 0.3 g / min and the reaction was continued for 3 h to obtain a core layer emulsion;

[0053] 3) 70 g of the core layer emulsion, 80 g of deionized water, 1 g of sodium lauryl sulfate, and 0.5 g of potassium persulfate were mixed evenly, purged with nitrogen, and heated to 90°C. A mixed solution of 25 g of methyl methacrylate and 2 g of a composite end-hydroxyl hyperbranched polyester was added at a rate of 0.2 g / min. The mixture was reacted for 3 h, and 1.5 g of calcium chloride was added to break the emulsion. The mixture was centrifuged and dried to obtain an acrylic PVC impact modifier.

[0054] The preparation method of the composite hydroxyl-terminated hyperbranched polyester of this embodiment includes the following steps: 66 g of dimethylolpropionic acid and 20 g of trimethylolpropane are uniformly mixed, nitrogen is passed through, the temperature is raised to 140° C., 1.2 g of p-toluenesulfonic acid is added, and the reaction is carried out for 2 h, 1.2 g of nanocellulose is added, and the reaction is carried out for 2 h, 10 g of dimethylolpropionic acid and 1 g of p-toluenesulfonic acid are added, and the reaction is continued for 3 h. After the reaction is completed, the nitrogen is stopped, the temperature is maintained unchanged, and the composite hydroxyl-terminated hyperbranched polyester is obtained by vacuum rotary evaporation for 3 h. The mixture is cooled to room temperature to obtain the composite hydroxyl-terminated hyperbranched polyester.

[0055] The preparation method of nanocellulose in this embodiment is as follows: 10g of natural cellulose is crushed, washed, and dried to obtain cellulose powder, and then the cellulose powder is evenly mixed with 120g of sulfuric acid with a mass percentage concentration of 64%, the temperature is adjusted to 45°C, and the reaction is carried out for 1 hour. After the reaction is completed, it is centrifuged and washed with deionized water until neutral, and finally washed with ethanol to obtain a nanocellulose suspension. The nanocellulose suspension is then ultrasonically treated at a power of 300W for 30 minutes, and freeze-dried to obtain nanocellulose.

[0056] Example 3

[0057] The preparation steps of the acrylic ester PVC impact modifier of this embodiment are as follows:

[0058] 1) Mix 50g of dimethylaminoethanol and 100g of ethyl acrylate, heat to 80°C, add 0.6g of hydroquinone and 2.5g of tetrabutyl titanate, react for 3h, then heat to 108°C and react for 5.5h to obtain a binder;

[0059] 2) 60 g of deionized water, 65 g of butyl acrylate, 0.5 g of divinylbenzene, and 0.6 g of sodium lauryl sulfate were mixed uniformly, purged with nitrogen, and heated to 75°C. 0.5 g of potassium persulfate was added and the mixture was reacted for 2.5 h. A mixed solution consisting of 0.6 g of potassium persulfate, 15 g of butyl acrylate, 10 g of a binder, and 0.8 g of divinylbenzene was added at a rate of 0.2 g / min and the reaction was continued for 2.5 h to obtain a core layer emulsion;

[0060] 3) 80 g of the core layer emulsion, 90 g of deionized water, 1.2 g of sodium lauryl sulfate, and 0.5 g of potassium persulfate were mixed evenly, purged with nitrogen, and heated to 85°C. A mixed solution of 25 g of methyl methacrylate and 6 g of a composite end-hydroxyl hyperbranched polyester was added at a rate of 0.3 g / min. The mixture was reacted for 2 h, and 2 g of calcium chloride was added to break the emulsion. The mixture was centrifuged and dried to obtain an acrylic PVC impact modifier.

[0061] The preparation method of the composite hydroxyl-terminated hyperbranched polyester of this embodiment includes the following steps: 60 g of dihydroxymethylacetic acid and 20 g of pentaerythritol are uniformly mixed, nitrogen is passed through, the temperature is raised to 135° C., 0.7 g of p-toluenesulfonic acid is added, the reaction is carried out for 1.2 hours, 1 g of nanocellulose is added, the reaction is carried out for 1.5 hours, 12 g of dihydroxymethylpropionic acid and 1.2 g of p-toluenesulfonic acid are added, the reaction is continued for 2.5 hours, and after the reaction is completed, the nitrogen is stopped, the temperature is maintained unchanged, and the composite hydroxyl-terminated hyperbranched polyester is obtained by vacuum rotary evaporation for 2.2 hours, and then cooled to room temperature to obtain the composite hydroxyl-terminated hyperbranched polyester.

[0062] The preparation method of nanocellulose in this embodiment is as follows: 10g of natural cellulose is crushed, washed, and dried to obtain cellulose powder, and then the cellulose powder is evenly mixed with 90g of sulfuric acid with a mass percentage concentration of 64%, the temperature is adjusted to 45°C, and the reaction is carried out for 1.8 hours. After the reaction is completed, the nanocellulose suspension is centrifuged and washed with deionized water until neutral, and finally washed with ethanol to obtain a nanocellulose suspension. The nanocellulose suspension is then ultrasonically treated at a power of 280W for 50 minutes, and freeze-dried to obtain nanocellulose.

[0063] Comparative Example 1

[0064] The preparation steps of the acrylic ester PVC impact modifier of this comparative example are as follows:

[0065] 1) 50 g of deionized water, 55 g of butyl acrylate, 0.4 g of divinylbenzene, and 0.6 g of sodium lauryl sulfate were mixed uniformly, purged with nitrogen, and heated to 75°C. 0.3 g of potassium persulfate was added and reacted for 2 h. A mixed solution consisting of 0.5 g of potassium persulfate, 22 g of butyl acrylate, and 0.5 g of divinylbenzene was added at a rate of 0.2 g / min and the reaction was continued for 2 h to obtain a core layer emulsion;

[0066] 2) 75 g of the core layer emulsion, 80 g of deionized water, 1.2 g of sodium lauryl sulfate, and 0.5 g of potassium persulfate were mixed evenly, purged with nitrogen, and heated to 80°C. A mixed solution of 25 g of methyl methacrylate and 5 g of a composite end-hydroxyl hyperbranched polyester was added at a rate of 0.3 g / min. The mixture was reacted for 1.5 h, and 1.8 g of calcium chloride was added to break the emulsion. The mixture was centrifuged and dried to obtain an acrylic PVC impact modifier.

[0067] The preparation method of the composite terminal hydroxyl hyperbranched polyester of this comparative example includes the following steps: 33 g of dihydroxymethylbutyric acid and 30 g of propylene glycol are uniformly mixed, nitrogen is passed through, the temperature is raised to 130° C., 0.7 g of p-toluenesulfonic acid is added, and the reaction is carried out for 1 hour, 0.6 g of nanocellulose is added, and the reaction is carried out for 1 hour, 8 g of dihydroxymethylpropionic acid and 1 g of p-toluenesulfonic acid are added, and the reaction is continued for 3 hours. After the reaction is completed, the nitrogen is stopped, the temperature is kept unchanged, and the composite terminal hydroxyl hyperbranched polyester is obtained by vacuum rotary evaporation for 2 hours. The mixture is cooled to room temperature to obtain the composite terminal hydroxyl hyperbranched polyester.

[0068] The preparation method of the nanocellulose in this comparative example is as follows: 10g of natural cellulose is crushed, washed, and dried to obtain cellulose powder, and then the cellulose powder and 80g of sulfuric acid with a mass percentage concentration of 64% are evenly mixed, the temperature is adjusted to 45°C, and the reaction is carried out for 2h. After the reaction is completed, it is centrifuged and washed with deionized water until neutral, and finally washed with ethanol to obtain a nanocellulose suspension. The nanocellulose suspension is then ultrasonically treated at a power of 200W for 60min, and freeze-dried to obtain nanocellulose.

[0069] Comparative Example 2

[0070] The preparation steps of the acrylic ester PVC impact modifier of this comparative example are as follows:

[0071] 1) Mix 50g of monoethanolamine and 70g of methyl acrylate, heat to 60°C, add 0.5g of hydroquinone and 2g of tetrabutyl titanate, react for 4h, then heat to 110°C and react for 5h to obtain a binder;

[0072] 2) 50 g of deionized water, 55 g of butyl acrylate, 0.4 g of divinylbenzene, and 0.6 g of sodium lauryl sulfate were mixed uniformly, purged with nitrogen, and heated to 75°C. 0.3 g of potassium persulfate was added and reacted for 2 h. A mixed solution consisting of 0.5 g of potassium persulfate, 12 g of butyl acrylate, 10 g of a binder, and 0.5 g of divinylbenzene was added at a rate of 0.2 g / min and the reaction was continued for 2 h to obtain a core layer emulsion;

[0073] 3) 75 g of the core layer emulsion, 80 g of deionized water, 1.2 g of sodium lauryl sulfate, and 0.5 g of potassium persulfate were mixed evenly, purged with nitrogen, and heated to 80°C. A mixed solution of 25 g of methyl methacrylate and 5 g of a hydroxyl-terminated hyperbranched polyester was added at a rate of 0.3 g / min. The mixture was reacted for 1.5 h, and 1.8 g of calcium chloride was added to break the emulsion. The mixture was centrifuged and dried to obtain an acrylic PVC impact modifier.

[0074] The preparation method of the terminal hydroxyl hyperbranched polyester of this comparative example comprises the following steps: uniformly mixing 33 g of dimethylolbutyric acid and 30 g of propylene glycol, passing nitrogen, heating to 130° C., adding 0.7 g of p-toluenesulfonic acid, and reacting for 2 h, then adding 8 g of dimethylolpropionic acid and 1 g of p-toluenesulfonic acid, and continuing the reaction for 3 h. After the reaction is completed, the nitrogen is stopped, the temperature is maintained constant, and vacuum rotary evaporation is performed for 2 h. The resultant mixture is cooled to room temperature to obtain the terminal hydroxyl hyperbranched polyester.

[0075] Performance testing

[0076] Preparation of modified polyvinyl chloride: 200g of polyvinyl chloride resin powder, 2g of methyltriethoxysilane, 1.5g of zinc stearate, 2g of stearic acid and 15g of acrylic ester PVC impact modifier were added to a high-speed mixer and mixed evenly. The mixed material was then placed on a double-roll rubber mixer and mixed for 8 minutes. The front roller temperature was controlled at 175°C, the rear roller temperature was controlled at 170°C, and the number of thin passes was controlled to 9. The resulting sheet was stacked in a mold, preheated in a hydraulic press at 180°C for 10 minutes, pressurized to 100 MPa and maintained at pressure for 5 minutes, and cold pressed to room temperature to obtain modified polyvinyl chloride.

[0077] 1. Tensile performance test: Referring to the standard GB / T1040.3-2006, the modified polyvinyl chloride was made into a dumbbell-shaped specimen and tested with an electronic universal testing machine. The test temperature was 23°C, the tensile speed was 20mm / min, and the specimen size was 150mm long × 20mm wide × 4mm thick. The test results are as follows: Figure 1 shown.

[0078] 2. Impact resistance test: Referring to the standard GB / T1043.1-2008, the modified polyvinyl chloride was made into a notched impact specimen, placed for 24 hours, and the stress of the specimen was eliminated. Then, an impact test was performed using an impact testing machine. The specimen size was 80mm long × 10mm wide × 4mm thick. The test results are as follows: Figure 2 shown.

[0079] Analyze Examples 1-3 and Comparative Examples 1-2 and combine Figure 1-2 It can be seen that the addition of binders and composite end-hydroxyl hyperbranched polyesters in the preparation process of acrylic PVC impact modifiers has a good effect on improving the toughening properties of the impact modifier. When acrylic PVC impact modifiers are used in polyvinyl chloride, the impact resistance of polyvinyl chloride is improved, and the tensile properties are also improved. However, when acrylic PVC impact modifiers without binders and nanocellulose are used in polyvinyl chloride, the impact resistance and tensile properties of polyvinyl chloride are poor.

[0080] 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 non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing an acrylic ester PVC impact modifier, characterized in that: The following steps are involved: 1) aminoethanol, acrylate, hydroquinone and tetrabutyl titanate are mixed and polymerized to obtain a binder; 2) mixing deionized water, butyl acrylate, divinylbenzene, sodium lauryl sulfate, potassium persulfate and a binder, and performing a cross-linking polymerization reaction to obtain a core layer emulsion; 3) mixing the core layer emulsion, deionized water, sodium lauryl sulfate, potassium persulfate, methyl methacrylate, and the composite hydroxyl-terminated hyperbranched polyester, performing a polymerization reaction, adding calcium chloride to break the emulsion, and centrifugally drying to obtain an acrylic ester PVC impact modifier; The preparation method of the composite hydroxyl-terminated hyperbranched polyester comprises the following steps: uniformly mixing hydroxymethyl carboxylic acid and polyol, passing nitrogen, heating to 130-140° C., sequentially adding p-toluenesulfonic acid, nanocellulose, dimethylol propionic acid and p-toluenesulfonic acid, stopping passing nitrogen after the reaction is completed, maintaining the temperature constant, performing vacuum rotary evaporation for 2-3 hours, and cooling to room temperature to obtain the composite hydroxyl-terminated hyperbranched polyester; The hydroxymethyl carboxylic acid is one of dimethylol propionic acid, dimethylol butyric acid and dimethylol acetic acid; The polyol is one of glycerol, trimethylolpropane and pentaerythritol.

2. The method for preparing an acrylic ester PVC impact modifier according to claim 1, wherein: The preparation method of nanocellulose comprises the following steps: crushing natural cellulose to obtain cellulose powder, mixing the cellulose powder with sulfuric acid, stirring and reacting, washing after the reaction to obtain a nanocellulose suspension, ultrasonically treating the nanocellulose suspension, and freeze-drying to obtain the nanocellulose.

3. The method for preparing an acrylic ester PVC impact modifier according to claim 1, wherein: In the step 1), the aminoethanol is one of methylethanolamine, dimethylaminoethanol and monoethanolamine; and the acrylate is one of methyl acrylate, ethyl acrylate and butyl acrylate.

4. The method for preparing an acrylic ester PVC impact modifier according to claim 1, wherein: In the step 1), the mass ratio of aminoethanol to acrylate is 1:(1.4-3.5).

5. The method for preparing an acrylic ester PVC impact modifier according to claim 1, characterized in that: In the step 3), the mass ratio of methyl methacrylate to the composite hydroxyl-terminated hyperbranched polyester is 1:(0.08-0.25).

6. The method for preparing an acrylic ester PVC impact modifier according to claim 1, characterized in that: The mass ratio of the hydroxymethylcarboxylic acid, the polyol and the nanocellulose is (1.1-3.3):1:(0.02-0.06).

7. The method for preparing an acrylic ester PVC impact modifier according to claim 2, characterized in that: The power of the ultrasonic treatment is 200-300W, and the time is 30-60min.

8. An acrylic ester PVC impact modifier, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the acrylic ester PVC impact modifier according to claim 8 as a toughening agent in polyvinyl chloride plastics.

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