Preparation method of a high impact resistance MBS resin

Abstract

The invention discloses a preparation method of a high impact resistant MBS resin, belonging to the technical field of MBS resins. The preparation method consists of the following steps: preparing an auxiliary emulsifier, preparing a treating agent, preparing a seed latex, preparing a core layer, preparing a shell layer, and post-treatment; the preparation of the auxiliary emulsifier consists of the following steps: silane modification and branching modification; the preparation of the treating agent consists of the following steps: acyl chlorination and grafting; the MBS resin prepared by the invention has excellent toughness and weather resistance, has little influence on the transparency of PVC resin, can improve the cold resistance of PVC resin, and the prepared MBS resin has a moderate particle size and a uniform particle size distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of MBS resin, and particularly relates to a preparation method of a high impact resistance MBS resin. Background Art

[0002] MBS resin is a terpolymer of methyl methacrylate (M), butadiene (B) and styrene (S), and has a typical core-shell structure. It is one of the most commonly used impact modifiers in the processing of polyvinyl chloride (PVC) products. MBS resin has excellent toughening performance, can maximize the transparency of PVC resin, and can also improve the cold resistance of PVC resin.

[0003] Below 80°C, PVC resin is in a glassy state. Under the action of stress, the continuous glassy phase cannot prevent the rapid expansion of cracks, and finally notches and crack fractures are formed. Therefore, the impact resistance of PVC resin is poor. MBS resin has a typical core-shell structure. The core is a styrene-butadiene rubber that has been lightly cross-linked and has a low shear modulus, which mainly plays a role in improving the impact toughness of the polymer and can also increase the refractive index of MBS resin to ensure that MBS resin has a refractive index similar to that of PVC resin, thereby reducing the impact on the transparency of PVC resin. The shell is a hard shell layer formed by grafting styrene and methyl methacrylate, and its main function is to improve the compatibility between MBA resin and PVC resin, so that MBS resin can be evenly dispersed in PVC resin. Therefore, MBS resin and PVC resin are semi-compatible, that is, MBS resin has good interfacial compatibility with PVC resin and can maintain the integrity of particle shape after being mixed with PVC resin. When a sufficient amount of MBS resin is added to PVC resin, it will coalesce into an island structure in the PVC resin. When the material is subjected to external impact, the styrene-butadiene rubber core in the MBS resin is the stress concentration point. The stress causes it to deform, and crazes and shear bands are induced around it. The impact energy is dispersed and absorbed through the crazes and shear bands, enabling the PVC product to change from brittle fracture to ductile fracture, thereby achieving the toughening purpose.

[0004] Currently, the most commonly used method for producing MBS resin is emulsion polymerization. Specifically, butadiene and styrene are added to water, emulsified using an emulsifier, and then polymerized under the initiation of an initiator to form a styrene-butadiene rubber core. Then, styrene and methyl methacrylate are added for emulsion graft polymerization to obtain an MBS resin graft latex. Finally, through coagulation, dehydration, and drying, MBS powder is obtained. However, the above-mentioned preparation method has the following deficiencies: The reaction rate of emulsion polymerization is fast, the heat dissipation is large, and the temperature rise rate of the reaction system is fast, resulting in excessive crosslinking during the preparation of the core, and also causing self-polymerization of monomers, a decrease in the grafting rate, which leads to a high content of unsaturated double bonds in the prepared MBS resin, making it prone to aging under the action of heat and ultraviolet rays, with poor weather resistance. It also causes a decrease in the dispersibility of the prepared MBS resin in PVC resin, a decrease in the toughening effect, and affects the transparency of PVC resin; The auxiliaries used in emulsion polymerization, such as emulsifiers and initiators, are not easily removed, resulting in a high impurity content in the prepared MBS resin, manifested as a decrease in the toughening effect of the MBS resin, and affecting the transparency and cold resistance of PVC resin; The particle size of the prepared MBS resin is too small, making it difficult to coalesce into an island structure in PVC resin and induce crazes and shear bands when subjected to external impact, manifested as a poor toughening effect of the MBS resin.

[0005] To solve the above problems, the most commonly used method currently is to reduce the dosage of auxiliaries, but this will result in an uneven particle size distribution of the prepared MBS resin. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention provides a preparation method of a high-impact MBS resin. The prepared MBS resin has excellent toughness and weather resistance, has little impact on the transparency of PVC resin, can improve the cold resistance of PVC resin, and the particle size of the prepared MBS resin is moderate and the particle size distribution is uniform.

[0007] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A preparation method of a high-impact MBS resin, which consists of the following steps: preparing an auxiliary emulsifier, preparing a treatment agent, preparing a seed latex, preparing a core layer, preparing a shell layer, and post-treatment;

[0009] The preparation of the auxiliary emulsifier consists of the following steps: silane modification, branched modification;

[0010] For the silane modification, nano-titanium dioxide, vinyltriethoxysilane, deionized water, absolute ethanol, and glacial acetic acid are added to a reaction kettle. The temperature of the reaction kettle is controlled at 60 - 70 °C, and the stirring speed is controlled at 100 - 200 rpm. After stirring for 3 - 4 h, centrifugation is carried out, with the centrifugation speed controlled at 8000 - 9000 rpm and the time at 10 - 12 min. After centrifugation, the precipitate is washed 2 - 4 times with deionized water, and then vacuum drying is carried out. The temperature of the vacuum drying is controlled at 70 - 80 °C, the vacuum degree is 0.08 - 0.09 MPa, and the time is 2 - 3 h. After the vacuum drying is completed, silane-modified titanium dioxide is obtained;

[0011] In the silane modification, the mass ratio of nano-titanium dioxide, vinyltriethoxysilane, deionized water, absolute ethanol, and glacial acetic acid is 5 - 6:7 - 8:120 - 130:80 - 90:4 - 5;

[0012] The particle size of the nano-titanium dioxide is 20 nm;

[0013] For the branching modification, silane-modified titanium dioxide, 1,1,1,3,5,5,5-heptamethyltrisiloxane, deionized water, and palladium-carbon catalyst are added to a reaction kettle. The reaction kettle is sealed, and the air in the kettle is replaced with nitrogen. The temperature of the reaction kettle is controlled at 70 - 90 °C, and the stirring speed is controlled for 6 - 7 h. The reaction kettle is opened, filtered, and after recovering the palladium-carbon catalyst, the filter residue is washed 2 - 3 times with ether, and then vacuum drying is carried out. The temperature of the vacuum drying is controlled at 40 - 50 °C, the vacuum degree is 0.08 - 0.09 MPa, and the time is 2 - 3 h. After the vacuum drying is completed, an auxiliary emulsifier is obtained;

[0014] In the branching modification, the mass ratio of silane-modified titanium dioxide, 1,1,1,3,5,5,5-heptamethyltrisiloxane, deionized water, and palladium-carbon catalyst is 6 - 7:60 - 65:130 - 150:0.09 - 0.1;

[0015] The palladium loading of the palladium-carbon catalyst is 5%;

[0016] The preparation of the treatment agent consists of the following steps: acyl chlorination and grafting;

[0017] For the acyl chlorination, nano-titanium dioxide, trimellitic trichloride, triethylamine, and chloroform are added to a reaction kettle. The temperature of the reaction kettle is controlled at 40 - 45 °C, and the stirring speed is controlled at 100 - 200 rpm. After stirring for 20 - 25 h, filtration is carried out, and the filter residue is washed 3 - 4 times with chloroform, and then vacuum drying is carried out. The temperature of the vacuum drying is controlled at 40 - 50 °C, the vacuum degree is 0.08 - 0.09 MPa, and the time is 2 - 3 h. After the vacuum drying is completed, acyl chlorinated titanium dioxide is obtained;

[0018] In the acyl chlorination, the mass ratio of nano-titanium dioxide, trimesoyl chloride, triethylamine, and chloroform is 2 - 2.2:2.5 - 3:1.5 - 2:60 - 65;

[0019] The particle size of the nano-titanium dioxide is 20 nm;

[0020] In the grafting, add the acyl chlorinated titanium dioxide, high molecular weight polycaprolactone, low molecular weight polycaprolactone, and chloroform into the reaction kettle, control the temperature of the reaction kettle at 30 - 40 °C, control the stirring speed at 100 - 300 rpm, stir for 18 - 20 h, filter, wash the filter residue with chloroform 4 - 5 times, then carry out vacuum drying, control the temperature of the vacuum drying at 40 - 50 °C, the vacuum degree at 0.08 - 0.09 MPa, and the time at 2 - 3 h. After the vacuum drying is completed, a treating agent is obtained;

[0021] In the grafting, the mass ratio of acyl chlorinated titanium dioxide, high molecular weight polycaprolactone, low molecular weight polycaprolactone, and chloroform is 5 - 5.5:30 - 35:25 - 30:140 - 160;

[0022] The molecular weight of the high molecular weight polycaprolactone is 5000;

[0023] The molecular weight of the low molecular weight polycaprolactone is 1000;

[0024] In the preparation of the seed latex, add butadiene, styrene, sodium dodecylbenzenesulfonate, co-emulsifier, and deionized water into the reaction kettle, seal the reaction kettle, displace the air in the kettle with nitrogen, then control the temperature of the reaction kettle at 70 - 75 °C, control the stirring speed at 100 - 200 rpm, and at the same time use 60 a Co irradiation source for irradiation, control the total irradiation time at 4.5 - 5 h, the total irradiation dose at 35 - 40 kGy. After the irradiation is completed, discharge the material to obtain the seed latex;

[0025] In the preparation of the seed latex, the mass ratio of butadiene, styrene, sodium dodecylbenzenesulfonate, co-emulsifier, and deionized water is 25 - 30:20 - 25:0.05 - 0.06:5 - 6:280 - 300;

[0026] In the preparation of the core layer, add the seed latex, butadiene, styrene, sodium dodecylbenzenesulfonate, co-emulsifier, and deionized water into the reaction kettle, seal the reaction kettle, displace the air in the kettle with nitrogen, then control the temperature of the reaction kettle at 70 - 75 °C, control the stirring speed at 100 - 200 rpm, and at the same time use 60 a Co irradiation source for irradiation, control the total irradiation time at 5 - 6 h, the total irradiation dose at 25 - 30 kGy. After the irradiation is completed, discharge the material to obtain the styrene-butadiene latex;

[0027] In the preparation of the core layer, the mass ratio of the seed latex, butadiene, styrene, sodium dodecylbenzenesulfonate, auxiliary emulsifier, and deionized water is 300 - 320:60 - 65:15 - 20:0.07 - 0.08:15 - 20:160 - 170;

[0028] In the preparation of the shell layer, styrene - butadiene latex, methyl methacrylate, styrene, divinylbenzene, sodium dodecylbenzenesulfonate, auxiliary emulsifier, treatment agent, and deionized water are added to the reaction kettle. The reaction kettle is sealed, and the air in the kettle is replaced with nitrogen. Then, the temperature of the reaction kettle is controlled to 70 - 75 °C, and the stirring speed is controlled to 100 - 200 rpm. At the same time, 60 a Co irradiation source is used for irradiation. The total irradiation time is controlled to be 7 - 8 h, and the total irradiation dose is 50 - 60 kGy. After the irradiation is completed, the material is discharged to obtain MBS resin latex;

[0029] In the preparation of the shell layer, the mass ratio of the styrene - butadiene latex, methyl methacrylate, styrene, divinylbenzene, sodium dodecylbenzenesulfonate, auxiliary emulsifier, treatment agent, and deionized water is 500 - 550:20 - 22:40 - 45:2 - 3:0.07 - 0.08:10 - 15:8 - 10:20 - 25;

[0030] In the post - treatment, the MBS resin latex is demulsified, centrifuged, washed with water, and dried to obtain high - impact - resistant MBS resin.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) In the preparation method of the high - impact - resistant MBS resin of the present invention, the prepared MBS resin has excellent toughness. The impact strength of the PVC test specimen prepared by adding the MBS resin to the PVC resin can reach 39.1 - 40.5 KJ / m 2 at 23 °C, and the impact strength at - 40 °C can reach 17.5 - 18.2 KJ / m 2 ;

[0033] (2) In the preparation method of the high - impact - resistant MBS resin of the present invention, the prepared MBS resin has little influence on the transparency of the PVC resin. The light transmittance of the PVC test specimen prepared by adding the MBS resin to the PVC resin can reach 90.1 - 90.8%, and the haze can be reduced to 4.1 - 4.4%;

[0034] (3) In the preparation method of the high - impact - resistant MBS resin of the present invention, the prepared MBS resin has excellent weather resistance. After the MBS resin is placed at 50 °C for 30 days and then added to the PVC resin, the impact strength of the PVC test specimen at 23 °C can still reach 38.4 - 40.1 KJ / m2 ; After continuously irradiating the MBS resin under an ultraviolet lamp for 30 days, the impact strength of the PVC test specimen prepared by adding it to the PVC resin at 23 °C can still reach 38.7 - 40.2 KJ / m 2 ;

[0035] (4) The preparation method of the high-impact MBS resin of the present invention can improve the cold resistance of the PVC resin. After the PVC test specimen prepared by adding the MBS resin to the PVC resin is left standing at -30 °C for 30 days, the impact strength at 23 °C can still reach 38.9 - 40.4 KJ / m 2 , and the impact strength at -40 °C can still reach 17.2 - 18.0 KJ / m 2 ;

[0036] (5) The preparation method of the high-impact MBS resin of the present invention has a moderate particle size and a uniform particle size distribution. The particle size of the prepared MBS resin is 242 - 251 nm, and the particle size distribution index is 0.0775 - 0.0784. Detailed Embodiments

[0037] In order to have a clearer understanding of the technical features, objectives, and effects of the present invention, the detailed embodiments of the present invention are now described.

[0038] Example 1

[0039] A preparation method of a high-impact MBS resin is specifically as follows:

[0040] 1. Preparation of auxiliary emulsifier:

[0041] (1) Silane modification: Add 5 g of nano-titanium dioxide, 7 g of vinyltriethoxysilane, 120 g of deionized water, 80 g of absolute ethanol, and 4 g of glacial acetic acid to the reaction kettle. Control the temperature of the reaction kettle to 60 °C, the stirring speed to 100 rpm, stir for 3 h, then centrifuge, control the centrifugation speed to 8000 rpm, and the time to 10 min. After centrifugation, wash the precipitate with deionized water 2 times, and then perform vacuum drying. Control the temperature of the vacuum drying to 70 °C, the vacuum degree to 0.08 MPa, and the time to 2 h. After the vacuum drying is completed, silane-modified titanium dioxide is obtained;

[0042] The particle size of the nano-titanium dioxide is 20 nm;

[0043] (2)Branching modification: Add 6 g of silane-modified titanium dioxide, 60 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane, 130 g of deionized water, and 0.09 g of palladium-carbon catalyst into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, control the temperature of the reaction kettle to 70 °C, control the stirring speed to 6 h, open the reaction kettle, filter, recover the palladium-carbon catalyst, wash the filter residue with ether 2 times, and then carry out vacuum drying. Control the temperature of the vacuum drying to 40 °C, the vacuum degree to 0.08 MPa, and the time to 2 h. After the vacuum drying is completed, an auxiliary emulsifier is obtained;

[0044] The palladium loading of the palladium-carbon catalyst is 5%;

[0045] 2. Preparation of the treating agent:

[0046] (1)Acid chlorination: Add 2 g of nano-titanium dioxide, 2.5 g of trimellitic acid chloride, 1.5 g of triethylamine, and 60 g of chloroform into the reaction kettle. Control the temperature of the reaction kettle to 40 °C, control the stirring speed to 100 rpm, stir for 20 h, filter, wash the filter residue with chloroform 3 times, and then carry out vacuum drying. Control the temperature of the vacuum drying to 40 °C, the vacuum degree to 0.08 MPa, and the time to 2 h. After the vacuum drying is completed, acid chlorinated titanium dioxide is obtained;

[0047] The particle size of the nano-titanium dioxide is 20 nm;

[0048] (2)Grafting: Add 5 g of acid chlorinated titanium dioxide, 30 g of high molecular weight polycaprolactone, 25 g of low molecular weight polycaprolactone, and 140 g of chloroform into the reaction kettle. Control the temperature of the reaction kettle to 30 °C, control the stirring speed to 100 rpm, stir for 18 h, filter, wash the filter residue with chloroform 4 times, and then carry out vacuum drying. Control the temperature of the vacuum drying to 40 °C, the vacuum degree to 0.08 MPa, and the time to 2 h. After the vacuum drying is completed, a treating agent is obtained;

[0049] The molecular weight of the high molecular weight polycaprolactone is 5000;

[0050] The molecular weight of the low molecular weight polycaprolactone is 1000;

[0051] 3. Preparation of the seed latex: Add 25 g of butadiene, 20 g of styrene, 0.05 g of sodium dodecylbenzenesulfonate, 5 g of auxiliary emulsifier, and 280 g of deionized water into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, and then control the temperature of the reaction kettle to 70 °C, control the stirring speed to 100 rpm, and at the same time use 60 a Co irradiation source for irradiation. Control the total irradiation time to 4.5 h and the total irradiation dose to 35 kGy. After the irradiation is completed, discharge the material to obtain the seed latex with a particle size of 97 nm;

[0052] 4. Preparation of the core layer: Add 300 g of seed latex, 60 g of butadiene, 15 g of styrene, 0.07 g of sodium dodecylbenzenesulfonate, 15 g of auxiliary emulsifier, and 160 g of deionized water into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, then control the temperature of the reaction kettle to 70 °C and the stirring speed to 100 rpm. At the same time, use 60 a Co irradiation source for irradiation, control the total irradiation time to 5 h, the total irradiation dose to 25 kGy. After the irradiation is completed, discharge the material to obtain styrene-butadiene latex with a particle size of 137 nm;

[0053] 5. Preparation of the shell layer: Add 500 g of styrene-butadiene latex, 20 g of methyl methacrylate, 40 g of styrene, 2 g of divinylbenzene, 0.07 g of sodium dodecylbenzenesulfonate, 10 g of auxiliary emulsifier, 8 g of treating agent, and 20 g of deionized water into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, then control the temperature of the reaction kettle to 70 °C and the stirring speed to 100 rpm. At the same time, use 60 a Co irradiation source for irradiation, control the total irradiation time to 7 h, the total irradiation dose to 50 kGy. After the irradiation is completed, discharge the material to obtain MBS resin latex;

[0054] 6. Post-treatment: Demulsify, centrifuge, wash with water, and dry the MBS resin latex to obtain high impact resistance MBS resin.

[0055] Example 2

[0056] A preparation method of high impact resistance MBS resin, specifically:

[0057] 1. Preparation of the auxiliary emulsifier:

[0058] (1) Silane modification: Add 5.5 g of nano-titanium dioxide, 7.5 g of vinyltriethoxysilane, 125 g of deionized water, 85 g of absolute ethanol, and 4.5 g of glacial acetic acid into the reaction kettle. Control the temperature of the reaction kettle to 65 °C and the stirring speed to 150 rpm. After stirring for 3.5 h, centrifuge, control the centrifugation speed to 8500 rpm and the time to 11 min. After centrifugation, wash the precipitate with deionized water 3 times, then perform vacuum drying, control the temperature of the vacuum drying to 75 °C, the vacuum degree to 0.08 MPa, and the time to 2.5 h. After the vacuum drying is completed, obtain silane-modified titanium dioxide;

[0059] The particle size of the nano-titanium dioxide is 20 nm;

[0060] (2)Branching modification: Add 6.5 g of silane-modified titanium dioxide, 62 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane, 140 g of deionized water, and 0.09 g of palladium-carbon catalyst into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, control the temperature of the reaction kettle at 80 °C, control the stirring speed at 6.5 h, open the reaction kettle, filter, recover the palladium-carbon catalyst, wash the filter residue with ether 3 times, and then carry out vacuum drying. Control the temperature of vacuum drying at 45 °C, the vacuum degree at 0.08 MPa, and the time at 2.5 h. After the vacuum drying is completed, an auxiliary emulsifier is obtained;

[0061] The palladium loading of the palladium-carbon catalyst is 5%;

[0062] 2. Preparation of treatment agent:

[0063] (1)Acid chlorination: Add 2.1 g of nano-titanium dioxide, 2.8 g of trimellitic trichloride, 1.8 g of triethylamine, and 62 g of chloroform into the reaction kettle. Control the temperature of the reaction kettle at 42 °C, control the stirring speed at 150 rpm, stir for 22 h, filter, wash the filter residue with chloroform 3 times, and then carry out vacuum drying. Control the temperature of vacuum drying at 45 °C, the vacuum degree at 0.085 MPa, and the time at 2.5 h. After the vacuum drying is completed, acid chlorinated titanium dioxide is obtained;

[0064] The particle size of the nano-titanium dioxide is 20 nm;

[0065] (2)Grafting: Add 5.2 g of acid chlorinated titanium dioxide, 32 g of high molecular weight polycaprolactone, 27 g of low molecular weight polycaprolactone, and 150 g of chloroform into the reaction kettle. Control the temperature of the reaction kettle at 35 °C, control the stirring speed at 200 rpm, stir for 19 h, filter, wash the filter residue with chloroform 4 times, and then carry out vacuum drying. Control the temperature of vacuum drying at 45 °C, the vacuum degree at 0.085 MPa, and the time at 2.5 h. After the vacuum drying is completed, a treatment agent is obtained;

[0066] The molecular weight of the high molecular weight polycaprolactone is 5000;

[0067] The molecular weight of the low molecular weight polycaprolactone is 1000;

[0068] 3. Preparation of seed latex: Add 28 g of butadiene, 22 g of styrene, 0.06 g of sodium dodecylbenzenesulfonate, 5.5 g of auxiliary emulsifier, and 290 g of deionized water into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, and then control the temperature of the reaction kettle at 72 °C, control the stirring speed at 150 rpm, and at the same time use 60Irradiate with a Co irradiation source, control the total irradiation time to 4.5 h, and the total irradiation dose to 35 kGy. After irradiation, discharge the material to obtain seed latex with a particle size of 100 nm;

[0069] 4. Prepare the core layer: Add 310 g of seed latex, 62 g of butadiene, 18 g of styrene, 0.08 g of sodium dodecylbenzenesulfonate, 18 g of auxiliary emulsifier, and 165 g of deionized water into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, then control the temperature of the reaction kettle to 72 °C and the stirring speed to 150 rpm. At the same time, use 60 a Co irradiation source for irradiation, control the total irradiation time to 5.5 h, and the total irradiation dose to 30 kGy. After irradiation, discharge the material to obtain styrene-butadiene latex with a particle size of 144 nm;

[0070] 5. Prepare the shell layer: Add 520 g of styrene-butadiene latex, 21 g of methyl methacrylate, 42 g of styrene, 2.5 g of divinylbenzene, 0.08 g of sodium dodecylbenzenesulfonate, 12 g of auxiliary emulsifier, 9 g of treatment agent, and 22 g of deionized water into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, then control the temperature of the reaction kettle to 72 °C and the stirring speed to 150 rpm. At the same time, use 60 a Co irradiation source for irradiation, control the total irradiation time to 7.5 h, and the total irradiation dose to 55 kGy. After irradiation, discharge the material to obtain MBS resin latex;

[0071] 6. Post-treatment: Demulsify, centrifuge, wash with water, and dry the MBS resin latex to obtain high-impact MBS resin.

[0072] Example 3

[0073] A preparation method of high-impact MBS resin, specifically:

[0074] 1. Prepare the auxiliary emulsifier:

[0075] (1) Silane modification: Add 6 g of nano-titanium dioxide, 8 g of vinyltriethoxysilane, 130 g of deionized water, 90 g of absolute ethanol, and 5 g of glacial acetic acid into the reaction kettle. Control the temperature of the reaction kettle to 70 °C and the stirring speed to 200 rpm. After stirring for 4 h, centrifuge, control the centrifugation speed to 9000 rpm and the time to 12 min. After centrifugation, wash the precipitate 4 times with deionized water, and then perform vacuum drying. Control the temperature of vacuum drying to 80 °C, the vacuum degree to 0.09 MPa, and the time to 3 h. After vacuum drying, obtain silane-modified titanium dioxide;

[0076] The particle size of the nano-titanium dioxide is 20 nm;

[0077] (2)Branching modification: Add 7 g of silane-modified titanium dioxide, 65 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane, 150 g of deionized water, and 0.1 g of palladium-carbon catalyst into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, control the temperature of the reaction kettle to 90 °C, control the stirring speed to 7 h, open the reaction kettle, filter, recover the palladium-carbon catalyst, wash the filter residue 3 times with diethyl ether, and then carry out vacuum drying. Control the temperature of vacuum drying to 50 °C, the vacuum degree to 0.09 MPa, and the time to 3 h. After the vacuum drying is completed, an auxiliary emulsifier is obtained;

[0078] The palladium loading of the palladium-carbon catalyst is 5%;

[0079] 2. Preparation of treatment agent:

[0080] (1)Acid chlorination: Add 2.2 g of nano-titanium dioxide, 3 g of trimellitic acid chloride, 2 g of triethylamine, and 65 g of chloroform into the reaction kettle. Control the temperature of the reaction kettle to 45 °C, control the stirring speed to 200 rpm, stir for 25 h, filter, wash the filter residue 4 times with chloroform, and then carry out vacuum drying. Control the temperature of vacuum drying to 50 °C, the vacuum degree to 0.09 MPa, and the time to 3 h. After the vacuum drying is completed, acid chlorinated titanium dioxide is obtained;

[0081] The particle size of the nano-titanium dioxide is 20 nm;

[0082] (2)Grafting: Add 5.5 g of acid chlorinated titanium dioxide, 35 g of high molecular weight polycaprolactone, 30 g of low molecular weight polycaprolactone, and 160 g of chloroform into the reaction kettle. Control the temperature of the reaction kettle to 40 °C, control the stirring speed to 300 rpm, stir for 20 h, filter, wash the filter residue 5 times with chloroform, and then carry out vacuum drying. Control the temperature of vacuum drying to 50 °C, the vacuum degree to 0.09 MPa, and the time to 3 h. After the vacuum drying is completed, a treatment agent is obtained;

[0083] The molecular weight of the high molecular weight polycaprolactone is 5000;

[0084] The molecular weight of the low molecular weight polycaprolactone is 1000;

[0085] 3. Preparation of seed latex: Add 30 g of butadiene, 25 g of styrene, 0.06 g of sodium dodecylbenzenesulfonate, 6 g of auxiliary emulsifier, and 300 g of deionized water into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, and then control the temperature of the reaction kettle to 75 °C, control the stirring speed to 200 rpm, and at the same time use 60 Co irradiation source for irradiation, control the total irradiation time to 5 h, the total irradiation dose to 40 KGy. After the irradiation is completed, discharge the material to obtain seed latex with a particle size of 102 nm;

[0086] 4. Preparation of the core layer: Add 320 g of seed latex, 65 g of butadiene, 20 g of styrene, 0.08 g of sodium dodecylbenzenesulfonate, 20 g of auxiliary emulsifier, and 170 g of deionized water into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, then control the temperature of the reaction kettle to 75 °C and the stirring speed to 200 rpm. At the same time, use 60 a Co irradiation source for irradiation, control the total irradiation time to 6 h, the total irradiation dose to 30 KGy. After the irradiation is completed, discharge the material to obtain styrene-butadiene latex with a particle size of 138 nm;

[0087] 5. Preparation of the shell layer: Add 550 g of styrene-butadiene latex, 22 g of methyl methacrylate, 45 g of styrene, 3 g of divinylbenzene, 0.08 g of sodium dodecylbenzenesulfonate, 15 g of auxiliary emulsifier, 10 g of treating agent, and 25 g of deionized water into the reaction kettle. Seal the reaction kettle, displace the air in the kettle with nitrogen, then control the temperature of the reaction kettle to 75 °C and the stirring speed to 200 rpm. At the same time, use 60 a Co irradiation source for irradiation, control the total irradiation time to 8 h, the total irradiation dose to 60 KGy. After the irradiation is completed, discharge the material to obtain MBS resin latex;

[0088] 6. Post-treatment: Demulsify, centrifuge, wash with water, and dry the MBS resin latex to obtain high-impact MBS resin.

[0089] Comparative Example 1

[0090] The preparation method of the high-impact MBS resin described in Example 2 is adopted, and the difference is that: the preparation of the auxiliary emulsifier in Step 1 is omitted, and sodium dodecylbenzenesulfonate is used to equivalently replace the addition of the auxiliary emulsifier in Step 3 for preparing the seed latex, Step 4 for preparing the core layer, and Step 5 for preparing the shell layer.

[0091] In this comparative example, the particle size of the seed latex obtained in Step 3 for preparing the seed latex is 61 nm, and the particle size of the styrene-butadiene latex is 84 nm.

[0092] Comparative Example 2

[0093] The preparation method of the high-impact MBS resin described in Example 2 is adopted, and the difference is that: the preparation of the treating agent in Step 2 is omitted, and the addition of the treating agent is omitted in Step 5 for preparing the shell layer.

[0094] In this comparative example, the particle size of the seed latex obtained in Step 3 for preparing the seed latex is 103 nm, and the particle size of the styrene-butadiene latex is 142 nm.

[0095] Comparative Example 3

[0096] The preparation method of the high impact-resistant MBS resin described in Example 2 is adopted, with the difference that: the preparation of the auxiliary emulsifier in the first step is omitted, and the addition of the auxiliary emulsifier is omitted in the third step of preparing the seed latex, the fourth step of preparing the core layer, and the fifth step of preparing the shell layer.

[0097] In the fourth step of preparing the core layer, serious agglomeration and caking occurred, and it was impossible to carry out the fifth step of preparing the shell layer and the sixth step of post-treatment. Therefore, the MBS resin was not prepared.

[0098] Comparative Example 4

[0099] In view of the failure of Comparative Example 3, in order to further verify the effect of the auxiliary emulsifier, the amount of sodium dodecylbenzenesulfonate was reduced on the basis of Comparative Example 1, specifically:

[0100] The preparation method of the high impact-resistant MBS resin described in Example 2 is adopted, with the difference that: the preparation of the auxiliary emulsifier in the first step is omitted, and the amount of sodium dodecylbenzenesulfonate in the third step of preparing the seed latex, the fourth step of preparing the core layer, and the fifth step of preparing the shell layer is multiplied by 6.

[0101] In this comparative example, the particle size of the seed latex obtained in the third step of preparing the seed latex is 96 nm, and the particle size of the styrene-butadiene latex is 120 nm.

[0102] Test Example 1

[0103] The high impact-resistant MBS resins prepared in Examples 1-3 and Comparative Examples 1-2, 4 were added to the PVC resin to make PVC test specimens. The specific preparation method is as follows:

[0104] 1000 g of PVC resin, 70 g of high impact-resistant MBS resin, 10 g of calcium stearate, and 1.5 g of polyethylene wax were added to a high-speed mixer and stirred, and then extruded and molded in a twin-screw extruder to obtain a PVC test specimen;

[0105] The impact strength of the PVC test specimen at 23 °C, the impact strength at -40 °C, the light transmittance, and the haze were tested. The test results are as follows:

[0106]

[0107] It can be seen from the above results that by using the auxiliary emulsifiers in Examples 1-3 and Comparative Example 2 to replace some conventional emulsifiers, the impact strength of the PVC resin at 23 °C, the impact strength at -40 °C, and the light transmittance can be improved, and the haze can be reduced; by adding a treatment agent in the preparation of the shell layer, the impact strength of the PVC resin at 23 °C, the impact strength at -40 °C, and the light transmittance can also be improved, and the haze can be reduced;

[0108] In Examples 1-3 and Comparative Example 2, the auxiliary emulsifier is a reactive surfactant. The preparation method is as follows: First, modify nano-titanium dioxide with a silane coupling agent with double bonds to introduce carbon-carbon double bonds and silicon-oxygen bonds onto the nano-titanium dioxide. Then, through hydrosilylation, graft 1,1,1,3,5,5,5-heptamethyltrisiloxane onto some of the double bonds to obtain a surfactant with double bonds. The prepared reactive auxiliary emulsifier not only has excellent surface activation ability but can also participate in the reaction through the remaining double bonds to introduce Si-C-Si bonds into the MBS resin, improving the toughening performance of the MBS resin. At the same time, it can also avoid the too small particle size of the MBS resin and excessive residual emulsifier in the MBS resin caused by excessive emulsifier dosage, control the particle size of the MBS resin moderately, and further improve the toughening performance of the MBS resin. The core of the reactive auxiliary emulsifier is titanium dioxide. After introducing titanium dioxide, it can increase the transparency of the MBS resin and reduce the haze. At the same time, the addition of the auxiliary emulsifier can replace the addition of some emulsifiers, thus greatly reducing the residual amount of conventional emulsifiers, improving the transparency of the PVC resin, and reducing the haze of the PVC resin.

[0109] The treatment agent has titanium dioxide as the core, and polycaprolactone with different molecular weights is grafted onto the core titanium dioxide. The polycaprolactone with different molecular weights can form a toothed structure on the outer layer, thereby increasing the contact area during crosslinking. Due to the hydrophobicity of polycaprolactone, it will enter the reaction system along with methyl methacrylate and styrene during the preparation of the shell layer. Polycaprolactone contains ester bonds, and the ester bonds can crosslink with each other to form a crosslinked network in the shell layer. Due to the excellent compatibility of polycaprolactone, it can further improve the compatibility between the prepared MBS resin and PVC resin, and can also increase the crosslinking density of the shell layer, thereby improving the toughening performance of the MBS resin. It can also further introduce titanium dioxide into the shell layer, thereby further increasing the transparency of the shell layer, avoiding the influence of the increased crosslinking density on the transparency of the shell layer, improving the transparency of the PVC resin, and reducing the haze of the PVC resin.

[0110] Test Example 2

[0111] The high-impact MBS resins prepared in Examples 1-3 and Comparative Examples 1-2, 4 were left standing at 50 °C for 30 d, and then added to PVC resin according to the method of Test Example 1 to prepare PVC test specimens. The impact strength of the PVC test specimens at 23 °C was tested, and the test results are as follows:

[0112]

[0113] Test Example 3

[0114] The high-impact MBS resins prepared in Examples 1-3 and Comparative Examples 1-2, 4 were continuously irradiated under an ultraviolet lamp for 30 days. The wavelength of the ultraviolet light used during irradiation was controlled at 313 nm, and the temperature was 25 °C. Then, they were added to PVC resin according to the method of Test Example 1 to prepare PVC test specimens, and the impact strength of the PVC test specimens at 23 °C was tested. The test results are as follows:

[0115]

[0116] From the results of Test Example 2 and Test Example 3, it can be seen that by using the auxiliary emulsifiers in Examples 1-3 and Comparative Example 2 to replace some of the conventional emulsifiers, and adding a treating agent to the shell layer during preparation, the stability of MBS resin under heat and ultraviolet light can be improved;

[0117] The addition of the auxiliary emulsifier containing double bonds can participate in the emulsion polymerization and react with the remaining unreacted double bonds, thereby reducing the number of double bonds in the MBS resin and improving the stability of the MBS resin under heat and ultraviolet light;

[0118] The addition of the treating agent can form a crosslinked network in the shell layer of the MBS resin, thereby improving the stability of MBS under heat and ultraviolet light.

[0119] Test Example 4

[0120] The high-impact MBS resins prepared in Examples 1-3 and Comparative Examples 1-2, 4 were added to PVC resin according to the method of Test Example 1 to prepare PVC test specimens. Then, the PVC test specimens were left standing at -30 °C for 30 days, and then the impact strength of the PVC test specimens at 23 °C and the impact strength at -40 °C were tested. The test results are as follows:

[0121]

[0122] From the above results, it can be seen that by using the auxiliary emulsifiers in Examples 1-3 and Comparative Example 2 to replace some of the conventional emulsifiers, and adding a treating agent to the shell layer during preparation, the cold resistance of MBS resin can be improved;

[0123] The improvement effect of the auxiliary emulsifier on cold resistance is mainly achieved by reducing the dosage of the conventional emulsifier, thereby reducing the residue of the conventional emulsifier and reducing the number of double bonds in the MBS resin; the improvement effect of the treating agent is mainly achieved by increasing the crosslinking density of the shell layer.

[0124] Test Example 5

[0125] The particle size and particle size distribution index of the high-impact MBS resins prepared in Examples 1-3 and Comparative Examples 1-2, 4 were tested. The test results are as follows:

[0126]

[0127] As can be seen from the above results, by using the auxiliary emulsifiers in Examples 1-3 and Comparative Example 2 to replace some of the conventional emulsifiers, and adding a treating agent to the shell layer during preparation, the particle size of the MBS resin can be increased and the particle size distribution index can be decreased;

[0128] The addition of the auxiliary emulsifier with double bonds can react through the double bonds with the monomers to introduce Si-C-Si bonds and titanium dioxide, thereby increasing the particle size while reducing the number of double bonds in the MBS resin, and at the same time, it can also avoid affecting the toughening performance, transparency, and cold resistance of MBS;

[0129] The addition of the treating agent can increase the crosslinking density of the shell layer and further introduce titanium dioxide, thereby increasing the particle size. The toothed structure of the treating agent is more conducive to cohesion into an island structure in the PVC resin, and polycaprolactone has a certain elasticity. When subjected to external force impact, it can induce the generation of crazes and shear bands starting from the shell layer, further improving the toughening performance of the MBS resin;

[0130] Therefore, the function of adding the treating agent is to increase the crosslinking degree of the shell layer and further improve the compatibility with the PVC resin, and it also has a certain improvement effect on the toughening performance, transparency, and cold resistance of the MBS resin, thereby achieving an increase in the particle size while avoiding affecting the comprehensive performance of the MBS resin.

[0131] Unless otherwise specified, the percentages used in the present invention are all mass percentages.

[0132] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, 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 high-impact MBS resin, characterized in that: The method comprises the following steps: preparing an auxiliary emulsifier, preparing a treating agent, preparing a seed latex, preparing a core layer, preparing a shell layer, and post-processing; The preparation of the auxiliary emulsifier comprises the following steps: silane modification, branching modification; The silane modification comprises adding nano titanium dioxide, vinyl triethoxysilane, deionized water, anhydrous ethanol and glacial acetic acid into a reaction kettle, controlling the temperature of the reaction kettle to 60-70° C., stirring, centrifuging, washing the precipitate, and vacuum drying to obtain silane-modified titanium dioxide; The branched modification comprises adding silane-modified titanium dioxide, 1,1,1,3,5,5,5-heptamethyltrisiloxane, deionized water and palladium-carbon catalyst into a reaction kettle, sealing the reaction kettle, replacing the air in the reaction kettle with nitrogen, controlling the temperature of the reaction kettle to 70-90° C., stirring, filtering, recovering the palladium-carbon catalyst, washing the filter residue, and then vacuum drying to obtain an auxiliary emulsifier; The preparation of the treating agent comprises the following steps: chlorination and grafting; The chlorination process comprises adding nano titanium dioxide, trimesoyl chloride, triethylamine and chloroform into a reaction kettle, controlling the temperature of the reaction kettle to 40-45° C., stirring, filtering, washing the filter residue, and then vacuum drying to obtain chlorinated titanium dioxide; The grafting comprises adding acyl chloride titanium dioxide, high molecular weight polycaprolactone, low molecular weight polycaprolactone and chloroform into a reaction kettle, controlling the temperature of the reaction kettle to 30-40° C., stirring, filtering, washing the filter residue, and then vacuum drying to obtain a treatment agent; In the preparation of the core layer, seed latex, butadiene, styrene, sodium dodecylbenzene sulfonate, auxiliary emulsifier, and deionized water are added to a reactor, the reactor is sealed, the air in the reactor is replaced with nitrogen, and the temperature of the reactor is controlled to 70-75° C., and stirred. 60 Co radiation source is used for irradiation to obtain styrene-butadiene latex; In the preparation of the shell layer, styrene-butadiene latex, methyl methacrylate, styrene, divinylbenzene, sodium dodecylbenzene sulfonate, auxiliary emulsifier, treating agent and deionized water are added into a reaction kettle, the reaction kettle is sealed, the air in the reaction kettle is replaced with nitrogen, and then the temperature of the reaction kettle is controlled to 70-75° C., and stirred. 60 Co radiation source is used for irradiation to obtain MBS resin latex.

2. The method for preparing high-impact MBS resin according to claim 1, characterized in that: In the silane modification, the mass ratio of nano titanium dioxide, vinyl triethoxysilane, deionized water, anhydrous ethanol, and glacial acetic acid is 5-6:7-8:120-130:80-90:4-5; The particle size of the nano titanium dioxide is 20 nm.

3. The method for preparing high-impact MBS resin according to claim 1, characterized in that: In the branching modification, the mass ratio of silane-modified titanium dioxide, 1,1,1,3,5,5,5-heptamethyltrisiloxane, deionized water, and palladium-carbon catalyst is 6-7:60-65:130-150:0.09-0.1; The palladium-carbon catalyst has a palladium loading of 5%.

4. The method for preparing high impact MBS resin according to claim 1, characterized in that: In the acyl chloride, the mass ratio of nano titanium dioxide, trimesoyl chloride, triethylamine and chloroform is 2-2.2:2.5-3:1.5-2:60-65; The particle size of the nano titanium dioxide is 20 nm.

5. The method for preparing high impact MBS resin according to claim 1, characterized in that: In the grafting, the mass ratio of acyl chloride titanium dioxide, high molecular weight polycaprolactone, low molecular weight polycaprolactone and chloroform is 5-5.5:30-35:25-30:140-160; The molecular weight of the high molecular weight polycaprolactone is 5000; The molecular weight of the low molecular weight polycaprolactone is 1000.

6. The method for preparing high impact MBS resin according to claim 1, characterized in that: The seed latex is prepared by adding butadiene, styrene, sodium dodecylbenzene sulfonate, an auxiliary emulsifier and deionized water into a reactor, sealing the reactor, replacing the air in the reactor with nitrogen, and then controlling the temperature of the reactor to 70-75° C., stirring, and using 60 Co irradiation source for irradiation, controlling the total irradiation time to be 4.5-5h, the total irradiation dose to be 35-40KGy, and obtaining seed latex after the irradiation is completed; In the preparation of the seed latex, the mass ratio of butadiene, styrene, sodium dodecylbenzene sulfonate, auxiliary emulsifier and deionized water is 25-30:20-25:0.05-0.06:5-6:280-300.

7. The method for preparing high impact MBS resin according to claim 1, characterized in that: In the preparation of the core layer, using 60 When irradiated by Co irradiation source, the total irradiation time is 5-6h, and the total irradiation dose is 25-30KGy; In the preparation of the core layer, the mass ratio of seed latex, butadiene, styrene, sodium dodecylbenzene sulfonate, auxiliary emulsifier and deionized water is 300-320:60-65:15-20:0.07-0.08:15-20:160-170.

8. The method for preparing high impact MBS resin according to claim 1, characterized in that: In the preparation of the shell layer, using 60 When irradiated with Co irradiation source, the total irradiation time is 7-8h, and the total irradiation dose is 50-60KGy; In the preparation of the shell layer, the mass ratio of styrene-butadiene latex, methyl methacrylate, styrene, divinylbenzene, sodium dodecylbenzene sulfonate, auxiliary emulsifier, treating agent and deionized water is 500-550:20-22:40-45:2-3:0.07-0.08:10-15:8-10:20-25.

9. The method for preparing high impact MBS resin according to claim 1, characterized in that: The post-treatment includes demulsifying, centrifuging, washing and drying the MBS resin latex to obtain a high-impact MBS resin.

Images