High-impact polyvinyl chloride composition and preparation method thereof

Abstract

The invention discloses a high-impact polyvinyl chloride composition and a preparation method thereof, and belongs to the technical field of high polymer materials. According to the technical scheme, PVC resin, a stabilizer, a lubricant, modified titanium dioxide, fumed silica and an antioxidant are added into a high-speed mixing unit to be mixed, when the temperature is increased to 105 DEG C, an impact modifier and a coloring agent are added, stirring continues to be carried out, the temperature is increased to 120 DEG C, the materials are put into a low-speed mixing machine to be cooled, discharging is carried out when the temperature of the materials is reduced to 40 DEG C, and a finished product is obtained. The high-impact polyvinyl chloride composition is obtained. The pipe prepared from the composition has excellent impact resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a high-impact polyvinyl chloride composition and a preparation method thereof. Background Art

[0002] PVC is a brittle material and must be toughened and modified before it can be used in the production of PVC-M pipes. In order to improve the impact resistance of the pipe, a large amount of impact modifiers such as methyl methacrylate-butadiene-styrene terpolymer (MBS), acrylic copolymer (ACR), chlorinated polyethylene (CPE), acrylonitrile-butadiene-styrene terpolymer (ABS) are usually added to the formulation system. When the amount of impact modifier is small, the improvement effect on impact strength is not obvious; when the amount of impact modifier is large, the melt viscosity of the system will be increased, and the friction heat during processing will also reduce the stability of the material; another way is to increase the toughness by modifying the PVC resin itself. Chinese invention patent CN1510064A produces high-impact polyvinyl chloride resin by making core-shell copolymer emulsion from acrylate and alkyl acrylate and then polymerizing with vinyl chloride monomer; Chinese invention patent CN109553725A produces high-impact polyvinyl chloride resin by copolymerizing acrylate with PVC resin and generating cross-linked structure. This method of modifying the resin with the largest amount in the formula makes the cost very high. Inorganic additives such as calcium carbonate and titanium dioxide are indispensable additives in the PVC-M pipe formula. Although some literature proposes to use nano calcium carbonate to toughen PVC materials, due to the poor surface compatibility between inorganic materials and PVC resins, the added inorganic materials and PVC are more likely to produce "silver streaks" when subjected to external forces, causing damage.

[0003] The current research direction on the toughening of PVC is mainly focused on the modification of PVC resin and impact modifiers. The modification of inorganic fillers is also mainly based on simple surface modification using coupling agents. The toughening and strengthening effects have not yet reached the optimal level. Summary of the invention

[0004] The present invention provides a high-impact polyvinyl chloride composition and a preparation method thereof. Titanium dioxide is surface-modified by using a titanate coupling agent, and fumed silica is modified by using a silane coupling agent. Then, the surface-treated fumed silica particles are grafted with acrylic acid esters for modification, thereby achieving the effect of improving the impact strength of the special material composition, especially the low-temperature unnotched impact strength. The prepared composition is used for making polyvinyl chloride water supply pipes, and the composition has excellent impact resistance.

[0005] The technical solution of the present invention is:

[0006] In a first aspect, a high-impact polyvinyl chloride composition is disclosed, characterized in that it comprises the following raw materials in parts by weight:

[0007] PVC resin 100 parts

[0008] Stabilizer 1.2-1.5 parts

[0009] Impact modifier 5.0-6.0 parts

[0010] Lubricant 1.5-2.0 parts

[0011] Colorant 0.2-0.3 parts

[0012] Antioxidant 0.6-0.8 parts

[0013] Modified titanium dioxide 1.5-2.0 parts

[0014] Graft-modified fumed silica 5.0-6.0 parts

[0015] Preferably, the stabilizer is a methyltin mercaptan stabilizer, preferably TM-181FS produced by Rohm and Haas Company of the United States.

[0016] Preferably, the impact modifier is one or a combination of two or more of methyl methacrylate-butadiene-styrene terpolymer (MBS), acrylic copolymer (ACR), nitrile rubber (NBR), chlorinated polyethylene (CPE), and ethylene-vinyl acetate copolymer (EVA), preferably methyl methacrylate-butadiene-styrene terpolymer (MBS).

[0017] Preferably, the lubricant is two or more of oxidized polyethylene wax, microcrystalline wax, polyethylene wax, stearate, stearic acid, and amide compounds;

[0018] Preferably, the antioxidant is ethylene bis(ethylene oxide) bis(3-(5-tert-butyl-5-hydroxy-m-tolyl) propionate), preferably Irganox 245 from BASF; and the colorant is carbon black.

[0019] On the other hand, a method for preparing the high-impact polyvinyl chloride composition is provided, wherein PVC resin, stabilizer, lubricant, modified titanium dioxide, graft-modified fumed silica, and antioxidant are added to a high-speed mixing unit for mixing, and when the temperature is raised to 100-105°C, an impact modifier and a colorant are added, and the mixture is stirred and heated to 110-120°C, and the material is placed in a low-speed mixer for cooling, and the material is discharged when the temperature drops below 45°C, thereby obtaining a high-impact polyvinyl chloride composition.

[0020] Preferably, the titanium dioxide surface treatment method is as follows: dilute the coupling agent 1 with ethanol for standby use, the mass concentration of the coupling agent 1 is 50%, add the titanium dioxide into a mixer, then add the diluted coupling agent 1, stir and heat to 90°C, and fully volatilize the ethanol to obtain the modified titanium dioxide; the amount of the coupling agent 1 is 0.8%-1.0% of the weight of the titanium dioxide.

[0021] Preferably, the coupling agent 1 is a monoalkoxy titanate coupling agent, preferably the titanate TCA-K44 produced by Kenrich.

[0022] Preferably, the surface treatment method of fumed silica is as follows: diluting the coupling agent II with ethanol to a mass concentration of 2%, and placing the mixture at room temperature for 1 hour; adding the fumed silica to a mixer, adding the diluted coupling agent II according to the dosage requirements, stirring and heating to 90° C. to allow the ethanol to fully volatilize, thereby obtaining the fumed silica particles after surface treatment;

[0023] The method for grafting modification of gas phase silica is as follows: adding a certain amount of deionized water and an emulsifier into a reaction kettle, wherein the emulsifier is a compound of Tween-20, Tween-60 and sorbitan monolaurate polyoxyethylene (20) ether in a weight ratio of 1:1:2, stirring and heating to 45°C, then adding the surface treated gas phase silica particles and stirring to form an emulsion state, adding the grafting monomer methyl methacrylate and the initiator dibenzoyl peroxide according to the dosage requirements, keeping the temperature constant for 15 minutes, then heating to 55°C for reaction for 5 hours, adding a saturated solution of calcium chloride to break the emulsion, repeatedly washing with deionized water, and drying to obtain the grafted modified gas phase silica; the amount of methyl methacrylate monomer is 2.0%-3.0% of the weight of the surface treated gas phase silica.

[0024] Preferably, the second coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane having a double bond structure, preferably KH-570 from Jinan Xinglongda Chemical Company; the amount of the second coupling agent is 0.2%-0.4% of the weight of the fumed silica.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention uses a titanate coupling agent with an amino group to modify the surface of titanium dioxide, and uses a silane coupling agent to modify the inorganic filler fumed silica, and then grafts acrylic acid esters to modify the fumed silica particles after surface treatment, thereby improving the compatibility between the modified titanium dioxide and the PVC resin matrix and between the grafted modified fumed silica and the PVC resin matrix, and hydrogen bond structures are formed between the modified titanium dioxide, the grafted modified fumed silica, and between the modified titanium dioxide, the grafted modified fumed silica and the resin, thereby achieving the effect of improving the impact strength of the special material composition, especially the low-temperature unnotched impact strength. The prepared composition is used to make polyvinyl chloride water supply pipes, and the composition has excellent impact resistance. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with embodiments, but the present invention is not limited thereto.

[0028] The raw materials in the present invention are as follows: the PVC resin is produced by a suspension method, and the average polymerization degree of the PVC resin is P=1000;

[0029] The organic tin stabilizer used was TM-181FS produced by Rohm and Haas Company of the United States;

[0030] The impact modifier is a methyl methacrylate-butadiene-styrene terpolymer of model B-564 produced by Zhongyuan Chemical Co., Ltd.

[0031] The antioxidant used was Irganox245 produced by BASF;

[0032] The lubricant is a mixture of microcrystalline wax, polyethylene wax and oxidized polyethylene wax;

[0033] The colorant used is C-311 produced by Hebei Moyu Chemical;

[0034] The titanium dioxide is rutile titanium dioxide, and the titanium dioxide R-902 produced by DuPont;

[0035] The fumed silica was LM-150 from Cabot Corporation.

[0036] The preparation methods of the modified titanium dioxide and filler-grafted modified fumed silica in Examples 1-10 and Comparative Examples 1-4 are as follows:

[0037] 1) The modified titanium dioxide is prepared by the following method: the titanate TCA-K44 coupling agent produced by Kenrich is diluted with ethanol, the mass concentration of the titanate TCA-K44 coupling agent is 50%, the titanium dioxide is added into a mixer, and then the diluted titanate TCA-K44 coupling agent is added, and the mixture is stirred and heated to 90° C., and the ethanol is fully volatilized to obtain the modified titanium dioxide; the amount of the titanate TCA-K44 coupling agent used is 1.0% by weight of the titanium dioxide.

[0038] 2) The grafted modified fumed silica in Examples 1-5 was prepared by the following method. First, surface-treated fumed silica particles were prepared. The specific method was as follows: the coupling agent KH-570 from Jinan Xinglongda Chemical Co., Ltd. was diluted with ethanol. The mass concentration of the coupling agent KH-570 was 2%, and the mixture was placed at room temperature for 1 hour. The fumed silica was added to a mixer, and the diluted coupling agent KH-570 was added according to the dosage requirements. The mixture was stirred and heated to 90°C to allow the ethanol to fully volatilize, thereby obtaining surface-treated fumed silica particles. The amount of coupling agent KH-570 was 0.3% of the weight of the fumed silica.

[0039] The method for grafting modification of fumed silica is as follows: 500g of deionized water and 2.5% of the weight of deionized water emulsifier are added into a reaction kettle, wherein the emulsifier is Tween-20, Tween-60 and sorbitan monolaurate polyoxyethylene (20) ether in a weight ratio of 1:1:2, the reaction is stirred and heated to 45°C, and then the surface-treated fumed silica particles are added and stirred to form an emulsion state, and the grafting monomer methyl methacrylate and the initiator dibenzoyl peroxide are added according to the dosage requirements, the temperature is kept constant for 15 minutes, and then the temperature is raised to 55°C for reaction for 5 hours, a saturated solution of calcium chloride is added to break the emulsion, and the mixture is repeatedly washed with deionized water and dried to obtain the grafted modified fumed silica; the amount of methyl methacrylate monomer is 2.5% of the weight of the surface-treated fumed silica, and the amount of initiator dibenzoyl peroxide is 0.3% of the weight of the grafting monomer methyl methacrylate.

[0040] The specific input materials of each raw material in Examples 1-5 are shown in Table 1.

[0041] Table 1

[0042]

[0043]

[0044] In the preparation process of modified titanium dioxide in Examples 6-10, the amount of titanate TCA-K44 coupling agent used is 0.8% by weight of titanium dioxide; in the preparation process of surface-treated fumed silica particles, the amount of coupling agent KH-570 used is 0.3% by weight of fumed silica; in the preparation process of graft-modified fumed silica, the amount of methyl methacrylate monomer used is 3% by weight of fumed silica after surface treatment. Other preparation methods and amounts are the same as in Examples 1-5. The specific input materials of each raw material in Examples 6-10 are shown in Table 2.

[0045] Table 2

[0046] Recipe ingredients Example 6 Example 7 Example 8 Example 9 Example 10 PVC P=1000 100 100 100 100 100 Organic tin stabilizer TM-181FS 1.5 1.2 1.3 1.4 1.5 MBS B-564 6.0 5.8 5.6 5.4 5.0 Lubricant microcrystalline wax 0.6 0.6 0.6 0.6 0.6 Polyethylene wax 0.6 0.6 0.5 0.5 0.5 Irganox 245 0.8 0.7 0.6 0.8 0.7 Oxidized polyethylene wax 0.6 0.7 0.6 0.5 0.5 Graft-modified fumed silica 5.0 5.5 6.0 5.8 6.0 Modified titanium dioxide 2.0 1.7 1.8 1.6 1.5 C-311 0.20 0.25 0.30 0.25 0.25

[0047] Comparative Example 1

[0048] The difference from Example 1 is that in Comparative Example 1, LM-150 produced by Cabot Corporation without surface modification and R-902 produced by DuPont Corporation without modification were used, and other proportions and preparation methods were the same as those in Example 1.

[0049] Comparative Example 2

[0050] Different from Example 1, in Comparative Example 2, unmodified titanium dioxide R-902 from DuPont Company was used directly, and other proportions and preparation methods were the same as those in Example 1.

[0051] Comparative Example 3

[0052] Different from Example 1, in Comparative Example 3, LM-150 produced by Cabot Corporation was directly used as fumed silica without surface modification, and other proportions and preparation methods were the same as those in Example 1.

[0053] Comparative Example 4

[0054] Different from Example 1, in Comparative Example 4, graft-modified calcium carbonate is used instead of graft-modified fumed silica, and the preparation method of the graft-modified calcium carbonate is the same as the preparation method of the medium-modified fumed silica.

[0055] The feed ratio of the raw materials of Comparative Examples 1-4 is shown in Table 3.

[0056] Table 3

[0057]

[0058] The high-impact polyvinyl chloride compositions in Examples 1-10 and Comparative Examples 1-4 are prepared by the following method: PVC resin, stabilizer, lubricant, graft-modified fumed silica, modified titanium dioxide and antioxidant are added to a high- and low-speed mixer for mixing, and when the temperature reaches 105° C., an impact modifier and a colorant are added, and the temperature is continued to be stirred and raised to 120° C. The material is placed in a low-speed mixer for cooling, and the material is discharged when the material temperature drops to 40° C., thereby obtaining the corresponding composition.

[0059] The compositions prepared in Examples 1-10 and Comparative Examples 1-4 were prepared into standard bars, and the specific preparation method was as follows: the mixed materials were plasticized into sheets on a double-roll mill at a milling temperature of 180°C for 6 min; the sheets were then pressed into 4 mm thick sheets on a tablet press at a sheeting temperature of 190°C for 5 min; the pressed sheets were made into standard bars, and the standard bars were tested for tensile strength and simple supported beam impact strength. Tensile strength: tested according to GB / T 1040.1-2018 "Determination of tensile properties of plastics Part 1: General" and GB / T 1040.2-2022 "Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics"; Simple supported beam impact strength: tested according to GB / T 1043.1-2008 "Determination of impact properties of simply supported plastic beams Part 1: Non-instrumented impact test" requires the test to be conducted with the specimen notch type being Type A or unnotched. The specific test results are shown in Table 4-6.

[0060] The compositions prepared in Examples 1-10 were subjected to pipe extrusion. The specific extrusion method was as follows: the pellets were extruded into pipes on a conical twin-screw extruder at a temperature of 170° C. to 210° C. The pipes were cooled, cut, expanded, and packaged to obtain finished pipes. The pipe performance was tested according to the urban construction industry standard CJ / T272-2008 "Impact-resistant modified polyvinyl chloride (PVC-M) pipes and fittings for water supply", and the specific test results are shown in Tables 4 and 5.

[0061] Table 4

[0062]

[0063] Table 5

[0064]

[0065] Table 6

[0066]

[0067]

[0068] Compared with Comparative Examples 1-4, the high-impact polyvinyl chloride compositions prepared in Examples 1-10 all have high tensile strength and simply supported beam notched impact strength, and are not damaged by notched impact. Compared with Example 1, Comparative Example 1 uses untreated fumed silica and titanium dioxide, Comparative Example 2 only modifies the fumed silica, Comparative Example 3 only modifies the titanium dioxide, and Comparative Example 4 uses surface-modified calcium carbonate instead of fumed silica. The tensile and impact properties of Comparative Examples 1-4 are lower than those of Examples 1-10, and the The fact that the unnotched impact in ratios 1-4 was all broken fully demonstrates that the present invention uses titanate coupling agent to modify the surface of titanium dioxide, and the inorganic filler fumed silica is modified by silane coupling agent, and then the surface-treated fumed silica particles are grafted with acrylic esters to achieve the effect of improving the impact strength of the special material composition, especially the low-temperature unnotched impact strength. It can be seen from Tables 4 and 5 that the pipes prepared in Examples 1-10 of the present application have good impact properties, and the drop hammer impact and high-speed impact properties meet the requirements of standard performance.

Claims

1. A high impact polyvinyl chloride composition, characterized in that: The invention comprises the following raw materials in parts by weight: PVC resin 100 parts Stabilizer 1.2-1.5 parts Impact modifier 5.0-6.0 parts Lubricant 1.5-2.0 parts Colorant 0.2-0.3 parts Antioxidant 0.6-0.8 parts Modified titanium dioxide 1.5-2.0 parts 5.0-6.0 parts of graft-modified fumed silica.

2. The high-impact polyvinyl chloride composition according to claim 1, characterized in that The stabilizer is a methyltin mercaptan stabilizer, preferably TM-181FS.

3. The high-impact polyvinyl chloride composition according to claim 1, characterized in that The impact modifier is one or a combination of two or more of methyl methacrylate-butadiene-styrene terpolymer, acrylic copolymer, nitrile rubber, chlorinated polyethylene, and ethylene-ethyl acetate copolymer, preferably methyl methacrylate-butadiene-styrene terpolymer.

4. The high-impact polyvinyl chloride composition according to claim 1, characterized in that The lubricant is two or more of oxidized polyethylene wax, microcrystalline wax, polyethylene wax, stearate, stearic acid and amide compounds.

5. The high-impact polyvinyl chloride composition according to claim 1, characterized in that: The antioxidant is ethylene bis(ethylene oxide) bis(3-(5-tert-butyl-5-hydroxy-m-tolyl) propionate), preferably Irganox245 from BASF; the colorant is carbon black.

6. The method for preparing the high-impact polyvinyl chloride composition according to claim 1, characterized in that: Add PVC resin, stabilizer, lubricant, modified titanium dioxide, grafted modified fumed silica and antioxidant into a high-speed mixer for mixing. When the temperature is raised to 100-105°C, add impact modifier and colorant. Continue stirring and heat to 110-120°C. Put the materials into a low-speed mixer for cooling. When the material temperature drops below 45°C, discharge the materials to obtain a high-impact polyvinyl chloride composition.

7. The method for preparing the high-impact polyvinyl chloride composition according to claim 1, characterized in that: The specific method for surface treatment of titanium dioxide is as follows: dilute coupling agent 1 with ethanol for standby use, the mass concentration of coupling agent 1 is 50%, add titanium dioxide into a mixer, then add the diluted coupling agent 1, stir and heat to 90°C, and fully volatilize ethanol to obtain modified titanium dioxide; the amount of coupling agent 1 used is 0.8%-1.0% of the weight of titanium dioxide.

8. The method for preparing the high-impact polyvinyl chloride composition according to claim 7, characterized in that: The coupling agent 1 is a monoalkoxy titanate coupling agent, preferably the titanate TCA-K44 produced by Kenrich Company.

9. The method for preparing the high-impact polyvinyl chloride composition according to claim 6, characterized in that: The surface treatment method of fumed silica is as follows: diluting the coupling agent II with ethanol, the mass concentration of the coupling agent II is 1-3%, and placing it at room temperature for 1-2 hours; adding the fumed silica into a mixer, adding the diluted coupling agent II according to the dosage requirement, stirring and heating to 80-100° C. to fully volatilize the ethanol, so as to obtain the fumed silica particles after surface treatment; The method for grafting modification of gas phase silica is as follows: adding a certain amount of deionized water and an emulsifier into a reaction kettle, wherein the emulsifier is Tween-20, Tween-60 and sorbitan monolaurate polyoxyethylene (20) ether in a weight ratio of 1:0.5-2:1-3, stirring and heating to 40-50°C, then adding the gas phase silica particles after surface treatment and stirring to form an emulsion state, adding the grafting monomer methyl methacrylate and the initiator dibenzoyl peroxide according to the dosage requirements, keeping the temperature constant for 10-20 minutes, then heating to 50-60°C and reacting for 4-6 hours, adding a saturated solution of calcium chloride to break the emulsion, repeatedly washing with deionized water, and drying to obtain the grafted modified gas phase silica; the amount of methyl methacrylate monomer is 2.0%-3.0% of the weight of the gas phase silica after surface treatment.

10. The method for preparing the high-impact polyvinyl chloride composition according to claim 9, characterized in that: The second coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane with a double bond structure, preferably KH-570 from Jinan Xinglongda Chemical Company; the amount of the second coupling agent is 0.2%-0.4% of the weight of the fumed silica.

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