Silicon-containing acrylate-styrene-acrylonitrile core-shell graft copolymer and latex and preparation method thereof

Abstract

The invention discloses a silicon-containing acrylate-styrene-acrylonitrile core-shell graft copolymer, latex thereof and a preparation method. The microstructure of the core-shell graft copolymer sequentially comprises a core part, a core layer and a shell layer from the center to the periphery, wherein the core part comprises a structural unit formed by converting an acrylate monomer, a structural unit formed by converting a grafting agent and a structural unit formed by converting a cross-linking agent; the core layer comprises a structural unit formed by converting an acrylate monomer, a structural unit formed by converting a grafting agent and a structural unit formed by converting vinyl functional group-containing silicone oil; the shell layer comprises a structural unit formed by converting a vinyl aromatic monomer and a structural unit formed by converting a vinyl nitrile monomer. The silicon-containing acrylate-styrene-acrylonitrile core-shell grafted copolymer prepared by the preparation method disclosed by the invention is more excellent in impact resistance, and the problems of poor high-temperature resistance and low-temperature elasticity of acrylate rubber are solved.

Description

Technical Field

[0001] The present invention belongs to the field of polymer materials, and relates to an acrylate-styrene-acrylonitrile core-shell graft copolymer modified by active silicone oil, its latex and a preparation method thereof. Background Art

[0002] The styrene-acrylonitrile-butyl acrylate terpolymer (ASA resin) has mechanical properties similar to those of the acrylonitrile-butadiene-styrene terpolymer (ABS resin). Since the polyacrylate rubber with no double bond structure replaces the polybutadiene rubber in ABS, ASA is an important engineering plastic with weather resistance about 10 times higher than that of ABS. Moreover, after long-term outdoor use, it can still retain excellent impact resistance, and is significantly superior to ABS resin in terms of solvent resistance and coloring property. In addition, ASA is an antistatic material that can reduce dust on the resin surface area.

[0003] The main uses of the ASA core-shell graft copolymer include: one is used as a toughening modifier to modify polyvinyl chloride, polycarbonate, polyethylene terephthalate, nylon, etc.; the other is to blend with styrene-acrylonitrile copolymer (SAN resin) to make ASA resin, which is applied to automotive interior and exterior parts, outdoor building materials, household appliances, sports and leisure, and consumer electronics fields, among which the automotive field is the largest application field.

[0004] Although replacing the polybutadiene rubber in ABS with polyacrylate rubber in ASA can prepare a core-shell graft copolymer with excellent weather resistance, the most important factor affecting the toughening of the core-shell structure modifier is the glass transition temperature of the polymer. Generally, the lower the glass transition temperature of the rubber phase, the stronger the toughening effect of the core-shell structure modifier on the plastic. For example, when toughening SAN resin, the toughening efficiency of the ABS impact modifier on it is significantly higher than that of the ASA impact modifier on it. The reason is that the glass transition temperature of the polybutadiene in the rubber phase of the ABS impact modifier is much lower than that of the polyacrylate in the rubber phase of the ASA impact modifier.

[0005] Organosilicon (also known as silicone oil) is a polysiloxane with a siloxane main chain, and its basic structural unit is Si-O-Si. Due to the small intermolecular force and high molecular flexibility of siloxane, polysiloxane has a low glass transition temperature. Therefore, under the same rubber content, using polysiloxane with a lower Tg as one of the rubber sources of impact-resistant resin can improve the problems of poor high-temperature resistance and poor low-temperature elasticity of acrylate rubber, and obtain an ASA resin with more excellent impact resistance.

[0006] US07299677 adopts the seed emulsion polymerization method. First, a polysiloxane seed latex is synthesized, then butyl acrylate and a grafting agent are added for polymerization to coat it, and finally styrene and acrylonitrile are grafted. After the obtained grafted latex is demulsified and coagulated, it is blended with SAN resin to prepare a silicon-containing ASA resin with excellent impact performance. In this method, the process technology for preparing the polysiloxane seed latex is complex, uses many chemicals, is prone to gelation, and has a low reaction conversion rate. As a result, the cost of the finally prepared grafted product is high and its application is narrow.

[0007] Xia Jia of Southwest University of Science and Technology prepared a butyl acrylate emulsion modified with KH-570 (Si-PBA) by the emulsion polymerization method. A series of organosilicon-modified acrylonitrile-styrene-acrylate (Si-ASA) graft polymers were prepared by grafting styrene and acrylonitrile. This method introduces KH-570 to react to generate polysiloxane as the rubber source. The prepared Si-PBA rubber has a smaller particle size. Although it greatly improves the gloss, the impact toughness is not satisfactory, and the conversion rate is only about 80%. The recovery of organosiloxane is also a problem.

[0008] CN106519235B provides a polysiloxane-based crosslinking agent, a method for manufacturing a vinyl-based graft copolymer powder using the polysiloxane-based crosslinking agent, the vinyl-based graft copolymer powder obtained by this method, and a composition mainly composed of the powder and a thermoplastic resin. The molecular weight of the vinyl polysiloxane-based crosslinking agent in this method is relatively high, and its diffusivity is weak during the polymerization process. The Si-O-Si structure distribution of the prepared silicone-acrylic rubber is uneven, and the characteristics of polysiloxane cannot be well exerted.

[0009] CN1147516C first prepares a polysiloxane latex with a large particle size, then adds acrylate monomers in batches to form a silicone rubber - polyacrylate mixed rubber latex, and finally adds styrene and acrylonitrile to the mixed rubber latex for grafting to prepare a silicone rubber - polyacrylate mixed rubber graft. This method further increases the particle size of the polysiloxane - polyacrylate rubber by preparing a polysiloxane latex with a large particle size, and the impact is greatly improved. However, according to experience, directly preparing a large-particle-size polysiloxane system is mostly unstable and difficult to industrialize, and there is also a problem of high cost.

[0010] Therefore, those in the art need an ASA resin with good impact performance, a simple preparation process, industrial production feasibility, and low cost, as well as a preparation method thereof. Summary of the Invention

[0011] In view of the problems existing in the prior art, the present invention provides a silicone oil-modified core-shell structured acrylate-styrene-acrylonitrile graft copolymer, its latex and a preparation method thereof. In the preparation process of the large-particle-size polyacrylate latex, the present invention introduces a silicone oil containing multiple vinyl functional groups to prepare a silicone-containing polyacrylate rubber. By adding a vinyl silicone oil with appropriate molecular weight, vinyl content and viscosity, the present invention introduces a polyorganosiloxane segment with a low Tg. The reaction conversion rate of the silicone-containing polyacrylate rubber latex is high, the latex particle size can be regulated, and it is easy to obtain a large-particle-size latex. The impact resistance of the ASA resin prepared by the present invention is more excellent, which improves the problems of poor high-temperature resistance and poor low-temperature elasticity of the acrylate rubber, and well balances the impact toughness and surface gloss. The silicone oil-modified acrylate-styrene-acrylonitrile copolymer blend resin prepared by the present invention can meet the application scenarios with high requirements for gloss and toughness in the processing link.

[0012] Specifically, one aspect of the present invention provides a silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer, and the microstructure of the silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer sequentially includes a core part, a core layer and a shell layer from the center to the periphery;

[0013] Among them, the core part includes a structural unit converted from an acrylate monomer, a structural unit converted from a grafting agent, and a structural unit converted from a crosslinking agent;

[0014] The core layer includes a structural unit converted from an acrylate monomer, a structural unit converted from a grafting agent, and a structural unit converted from a vinyl-functional group-containing silicone oil;

[0015] The shell layer includes a structural unit converted from a vinyl aromatic monomer and a structural unit converted from a vinyl nitrile monomer;

[0016] The mass ratio of the core part to the core layer is (0.4-10):100;

[0017] The mass fraction of the shell layer in the silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer is 30%-60%;

[0018] In the core layer, the mass ratio of the structural unit converted from the vinyl-functional group-containing silicone oil to the structural unit converted from the acrylate monomer is (0.5-10):100.

[0019] In one or more embodiments, the vinyl-functional group-containing silicone oil is selected from one or more of a double-end vinyl silicone oil having the structure shown in Formula I and a terminal-side vinyl silicone oil having the structure shown in Formula II. In Formula I and Formula II, a, n and m represent the number of repeating units:

[0020]

[0021] In the present invention, in the terminal vinyl silicone oil shown in Formula II, the repeating units and the repeating unit can be arranged disorderly with respect to each other.

[0022] In one or more embodiments, the vinyl content of the vinyl-functional silicone oil is 0.1 wt% to 5 wt%.

[0023] In one or more embodiments, the viscosity of the vinyl-functional silicone oil is 1 to 100 mm 2 / s.

[0024] In one or more embodiments, the weight-average molecular weight of the vinyl-functional silicone oil is 50 - 5000.

[0025] In one or more embodiments, the vinyl content of the vinyl-functional silicone oil is 0.5 wt% to 4 wt%.

[0026] In one or more embodiments, the viscosity of the vinyl-functional silicone oil is 20 - 80 mm 2 / s.

[0027] In one or more embodiments, the weight-average molecular weight of the vinyl-functional silicone oil is 500 - 4000.

[0028] In one or more embodiments, the acrylate monomer in the core and the acrylate monomer in the shell are each independently one or more acrylate alkyl esters having the structural formula CH 2 =CHCOOR, where R is a C1 - C15 alkyl group, preferably a C1 - C4 linear alkyl group; preferably, the acrylate monomer in the core and the acrylate monomer in the shell are each independently selected from one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylbutyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, hexyl acrylate, heptyl acrylate, n-pentyl acrylate, and lauryl acrylate; preferably, the acrylate monomer in the core and the acrylate monomer in the shell are butyl acrylate.

[0029] In one or more embodiments, the grafting agent in the core and the grafting agent in the shell are each independently one or more compounds containing two or more different unsaturated vinyl functional groups; preferably, the grafting agent in the core and the grafting agent in the shell are each independently selected from one or more of allyl methacrylate, triallyl isocyanurate, triallylamine, and diallylamine; preferably, the grafting agent in the core and the grafting agent in the shell are allyl methacrylate.

[0030] In one or more embodiments, the crosslinking agent is one or more compounds containing two or more identical unsaturated vinyl functional groups; preferably, the crosslinking agent is selected from one or more of ethylene glycol dimethacrylate, 1,6 - hexanediol diacrylate, 1,4 - butanediol diacrylate, and 1,3 - propanediol diacrylate; preferably, the crosslinking agent is ethylene glycol dimethacrylate.

[0031] In one or more embodiments, the vinyl aromatic monomer is selected from one or more of styrene, α - methylstyrene, and p - methylstyrene, and preferably is styrene.

[0032] In one or more embodiments, the vinyl nitrile monomer is selected from one or two of acrylonitrile and methacrylonitrile, and preferably is acrylonitrile.

[0033] In one or more embodiments, in the core, the mass ratio of the structural unit converted from the grafting agent to the structural unit converted from the acrylate monomer is (0.2 - 5):100.

[0034] In one or more embodiments, in the core, the mass ratio of the structural unit converted from the crosslinking agent to the structural unit converted from the acrylate monomer is (0.2 - 5):100.

[0035] In one or more embodiments, in the core layer, the mass ratio of the structural unit converted from the grafting agent to the structural unit converted from the acrylate monomer is (0.2 - 2):100.

[0036] In one or more embodiments, the mass fraction of the structural unit converted from the vinyl aromatic monomer in the shell layer is 70% - 80%, and the mass fraction of the structural unit converted from the vinyl nitrile monomer in the shell layer is 20% - 30%.

[0037] In one or more embodiments, the diameter of the core is 70 - 130 nm.

[0038] In one or more embodiments, the diameter of the core layer is 150 - 600 nm.

[0039] Another aspect of the present invention provides a silicone acrylate - styrene - acrylonitrile core - shell graft copolymer latex, and the silicone acrylate - styrene - acrylonitrile core - shell graft copolymer latex is an aqueous dispersion of the silicone acrylate - styrene - acrylonitrile core - shell graft copolymer as described in any one of the embodiments herein.

[0040] The present invention also provides a method for preparing the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer described in any one of the embodiments herein or the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex described in any one of the embodiments herein. The method comprises the following steps:

[0041] (1) In the presence of water, an emulsifier, an electrolyte and a water-soluble initiator, reacting an acrylate monomer, a grafting agent and a crosslinking agent to form a core, thereby obtaining a seed latex;

[0042] (2) In the presence of water, an emulsifier, an electrolyte and a water-soluble initiator, reacting the seed latex obtained in step (1), an acrylate monomer, a grafting agent and a vinyl-functional silicone oil to form a core layer on the surface of the core, thereby obtaining a silicone polyacrylate latex;

[0043] (3) In the presence of water, an emulsifier, an electrolyte and an oil-soluble initiator, reacting the silicone polyacrylate latex obtained in step (2), a vinyl aromatic monomer and a vinyl nitrile monomer to form a shell layer on the surface of the core layer, thereby obtaining a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex.

[0044] In one or more embodiments, the emulsifiers in step (1), step (2) and step (3) are each independently selected from one or more of sodium dodecyl sulfate, sodium dodecylbenzenesulfate, sodium octadecyl sulfate, sodium oleate, potassium dodecyl sulfate, potassium dodecylbenzenesulfate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium oleate, potassium dodecylbenzenesulfonate, potassium octadecyl sulfate, potassium rosin and potassium oleate, and preferably sodium dodecyl sulfate.

[0045] In one or more embodiments, the electrolytes in step (1), step (2) and step (3) are each independently selected from one or more of sodium chloride, potassium chloride, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate, and preferably sodium bicarbonate.

[0046] In one or more embodiments, the water-soluble initiators in step (1) and step (2) are selected from one or more of sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate and hydrogen peroxide, and preferably potassium persulfate.

[0047] In one or more embodiments, the oil-soluble initiator in step (3) is selected from one or more of tert-butyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, benzoyl peroxide, diisopropylbenzene hydroperoxide, 3,5,5-trimethylhexanol peroxide, tert-butyl peroxymethylisobutyrate, azobisisobutyronitrile, azo-bis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, and azobis(isobutyric acid methyl ester), preferably cumene hydroperoxide.

[0048] In one or more embodiments, the particle size of the seed latex is 70 to 130 nm.

[0049] In one or more embodiments, the particle size of the silicon-containing polyacrylate latex is 150 to 600 nm.

[0050] In one or more embodiments, in step (1), the mass ratio of water to the acrylate monomer is (150 - 200):100.

[0051] In one or more embodiments, in step (1), the mass ratio of the emulsifier to the acrylate monomer is (0.5 - 3):100.

[0052] In one or more embodiments, in step (1), the mass ratio of the electrolyte to the acrylate monomer is (0.3 - 0.45):100.

[0053] In one or more embodiments, in step (1), the mass ratio of the water-soluble initiator to the acrylate monomer is (0.25 - 0.5):100.

[0054] In one or more embodiments, in step (1), part of the acrylate monomer, part of the grafting agent, part of the crosslinking agent, part of the water-soluble initiator, and part of the water are gradually added to the reaction system in the form of a first pre-emulsion during the reaction.

[0055] In one or more embodiments, the masses of the acrylate monomer, grafting agent, crosslinking agent, and water-soluble initiator in the first pre-emulsion are 60% - 90% of the masses of the acrylate monomer, grafting agent, crosslinking agent, and water-soluble initiator used in step (1);

[0056] In one or more embodiments, in step (1), the reaction temperature is 70 - 80 °C, and the reaction proceeds until the polymerization conversion rate ≥ 98%.

[0057] In one or more embodiments, in step (2), the mass ratio of the added water to the acrylate monomer is (150 - 200):100.

[0058] In one or more embodiments, in step (2), the mass ratio of the emulsifier to the acrylate monomer is (0.5 to 3):100.

[0059] In one or more embodiments, in step (2), the mass ratio of the electrolyte to the acrylate monomer is (0.3 - 0.45):100.

[0060] In one or more embodiments, in step (2), the mass ratio of the water-soluble initiator to the acrylate monomer is (0.25 to 0.5):100.

[0061] In one or more embodiments, in step (2), part of the acrylate monomer, part of the grafting agent, part of the vinyl-functional silicone oil, part of the water-soluble initiator, part of the emulsifier, and part of the water are gradually added to the reaction system in the form of a second pre-emulsion during the reaction.

[0062] In one or more embodiments, in the second pre-emulsion, the masses of the acrylate monomer, the grafting agent, the vinyl-functional silicone oil, the water-soluble initiator, and the emulsifier are 60% - 90% of the masses of the acrylate monomer, the grafting agent, the vinyl-functional silicone oil, the water-soluble initiator, and the emulsifier used in step (2), respectively.

[0063] In one or more embodiments, in step (2), the reaction temperature is 75 - 85 °C, and the reaction proceeds until the polymerization conversion rate ≥ 98%.

[0064] In one or more embodiments, in step (3), the mass ratio of the added water to the total mass of the silicone-containing polyacrylate latex dry matter, the vinyl aromatic monomer, and the vinyl nitrile monomer is (150 - 200):100.

[0065] In one or more embodiments, in step (3), the mass ratio of the emulsifier to the total mass of the silicone-containing polyacrylate latex dry matter, the vinyl aromatic monomer, and the vinyl nitrile monomer is (0.5 - 3):100.

[0066] In one or more embodiments, in step (3), the mass ratio of the electrolyte to the total mass of the silicone-containing polyacrylate latex dry matter, the vinyl aromatic monomer, and the vinyl nitrile monomer is (0.3 - 0.45):100.

[0067] In one or more embodiments, in step (3), the mass ratio of the oil-soluble initiator to the total mass of the silicone-containing polyacrylate latex dry matter, the vinyl aromatic monomer, and the vinyl nitrile monomer is (0.25 - 0.5):100.

[0068] In one or more embodiments, in step (3), part of the vinyl aromatic monomer, part of the vinyl nitrile monomer, part of the oil-soluble initiator, part of the emulsifier, and part of the water are gradually added to the reaction system in the form of a third pre-emulsion during the reaction.

[0069] In one or more embodiments, in the third pre-emulsion, the masses of the vinyl aromatic monomer, vinyl nitrile monomer, oil-soluble initiator, and emulsifier are 60% to 90% of the masses of the vinyl aromatic monomer, vinyl nitrile monomer, oil-soluble initiator, and emulsifier used in step (3), respectively.

[0070] In one or more embodiments, in step (3), the reaction temperature is 65 to 75 °C, and the reaction is carried out until the polymerization conversion rate is ≥ 98%.

[0071] In one or more embodiments, step (1) includes: adding an acrylate monomer, a grafting agent, a crosslinking agent, water, an emulsifier, an electrolyte, and a water-soluble initiator to a reactor, heating to 70 to 80 °C and reacting for 20 to 40 min, then maintaining the reaction temperature, adding the first pre-emulsion to the reactor within 3 to 4 h, and reacting at a constant temperature for 1 to 2 h until the polymerization conversion rate is ≥ 98%, and then stopping the reaction to obtain a seed latex; wherein the first pre-emulsion includes an acrylate monomer, a grafting agent, a crosslinking agent, a water-soluble initiator, and water, and the masses of the acrylate monomer, grafting agent, crosslinking agent, and water-soluble initiator in the first pre-emulsion are 60% to 90% of the masses of the acrylate monomer, grafting agent, crosslinking agent, and water-soluble initiator used in step (1), respectively.

[0072] In one or more embodiments, step (2) includes: adding the seed latex obtained in step (1), an acrylate monomer, a grafting agent, a vinyl-functional silicone oil, water, an emulsifier, an electrolyte, and a water-soluble initiator to a reactor, heating to 75 to 85 °C and reacting for 20 to 40 min, then maintaining the reaction temperature, adding the second pre-emulsion to the reactor within 3 to 4 h, and reacting at a constant temperature for 1 to 2 h until the polymerization conversion rate is ≥ 98%, and then stopping the reaction to obtain a silicone-containing polyacrylate latex, wherein the second pre-emulsion includes an acrylate monomer, a grafting agent, a vinyl-functional silicone oil, a water-soluble initiator, an emulsifier, and water, and the masses of the acrylate monomer, grafting agent, vinyl-functional silicone oil, water-soluble initiator, and emulsifier in the second pre-emulsion are 60% to 90% of the masses of the acrylate monomer, grafting agent, vinyl-functional silicone oil, water-soluble initiator, and emulsifier used in step (2), respectively.

[0073] In one or more embodiments, step (3) includes: adding the silicon-containing polyacrylate latex obtained in step (2), water, vinyl aromatic monomer, vinyl nitrile monomer, emulsifier, electrolyte, and oil-soluble initiator into a reactor, heating to 65-75 °C and reacting for 20-40 min, then maintaining the reaction temperature, adding the third pre-emulsion into the reactor within 3-4 h, and after adding, reacting at a constant temperature for 1-2 h until the polymerization conversion rate reaches ≥98%, stopping the reaction, and preparing a silicon-containing acrylate-styrene-acrylonitrile core-shell graft copolymer latex, wherein the third pre-emulsion includes vinyl aromatic monomer, vinyl nitrile monomer, oil-soluble initiator, emulsifier, and water, and the masses of the vinyl aromatic monomer, vinyl nitrile monomer, oil-soluble initiator, and emulsifier in the third pre-emulsion are 60%-90% of the masses of the vinyl aromatic monomer, vinyl nitrile monomer, oil-soluble initiator, and emulsifier used in step (3).

[0074] In one or more embodiments, the method for preparing a silicon-containing acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention further includes the following steps:

[0075] (4) Demulsifying, curing, washing, and drying the silicon-containing acrylate-styrene-acrylonitrile core-shell graft copolymer latex obtained in step (3) to obtain a silicon-containing acrylate-styrene-acrylonitrile core-shell graft copolymer.

[0076] Another aspect of the present invention provides a silicon-containing acrylate-styrene-acrylonitrile copolymer blend resin, which comprises the silicon-containing acrylate-styrene-acrylonitrile core-shell graft copolymer described in any one of the embodiments herein and an acrylonitrile-styrene copolymer.

[0077] In one or more embodiments, in the silicon-containing acrylate-styrene-acrylonitrile copolymer blend resin, the mass ratio of the silicon-containing acrylate-styrene-acrylonitrile core-shell graft copolymer to the acrylonitrile-styrene copolymer is 30:70 to 45:55;

[0078] In one or more embodiments, the silicon-containing acrylate-styrene-acrylonitrile copolymer blend resin further includes an antioxidant and / or a lubricant.

[0079] In one or more embodiments, relative to the total mass of 100 parts by mass of the silicon-containing acrylate-styrene-acrylonitrile core-shell graft copolymer and the acrylonitrile-styrene copolymer, the mass of the antioxidant is 0.2-0.5 parts by mass, and the mass of the lubricant is 0.2-0.5 parts by mass.

[0080] In one or more embodiments, the silicone acrylate-styrene-acrylonitrile copolymer blend resin is prepared by blending and extruding a raw material composition comprising the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer and the acrylonitrile-styrene copolymer.

[0081] In one or more embodiments, the extrusion temperature is 180-240 °C.

[0082] Another aspect of the present invention also provides the use of a vinyl-functional silicone oil in the preparation of an acrylate-styrene-acrylonitrile core-shell graft copolymer, wherein the vinyl-functional silicone oil is selected from one or more of a bis-terminal vinyl silicone oil having the structure shown in Formula I and a terminal-side vinyl silicone oil having the structure shown in Formula II. In Formulas I and II, a, n, and m represent the number of repeating units:

[0083]

[0084] In one or more embodiments, the vinyl-functional silicone oil has a vinyl content of 0.1 wt% to 5 wt%, a viscosity of 1 to 100 mm 2 / s, and a weight-average molecular weight of 50-5000.

[0085] In one or more embodiments, the vinyl-functional silicone oil has a vinyl content of 0.5 wt% to 4 wt%.

[0086] In one or more embodiments, the vinyl-functional silicone oil has a viscosity of 20 to 80 mm 2 / s.

[0087] In one or more embodiments, the vinyl-functional silicone oil has a weight-average molecular weight of 500 to 4000.

[0088] The present invention also provides a plastic comprising the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer according to any one of the embodiments herein or the silicone acrylate-styrene-acrylonitrile copolymer blend resin according to any one of the embodiments herein.

[0089] In one or more embodiments, the matrix resin of the plastic is polyvinyl chloride, polyamide, polycarbonate, polyoxymethylene, polyphenylene ether, polyester, polyimide, polyphenylene sulfide, polysulfone, polyether ether ketone, polyarylether ketone, or fluororesin. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] Figure 1 It is a schematic diagram of the microstructure of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer in some embodiments of the present invention.

[0091] The description of the reference numerals is as follows: 1 is the polyacrylate seed inner core, 2 is the polyacrylate seed outer core, 3 is the silicon-containing polyacrylate inner core, 4 is the silicon-containing polyacrylate outer core, 5 is the silicon-containing acrylate-styrene-acrylonitrile core-shell graft copolymer shell, and 6 is the Si-O-Si segment. Detailed implementation manners

[0092] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meaning understood by those skilled in the art for the present invention. In case of conflict, the definition in this specification shall prevail.

[0093] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not limit the scope of the present invention in any way, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0094] In this article, "comprising", "including", "containing" and similar terms cover the meanings of "consisting essentially of" and "consisting of". For example, when it is disclosed herein that "A comprises B and C", it should be considered that "A consists essentially of B and C" and "A consists of B and C" have been disclosed herein.

[0095] In this article, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are only for the sake of simplicity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub-ranges and individual values within the ranges (including integers and fractions).

[0096] In this article, unless otherwise specified, the percentage refers to the mass percentage, the ratio refers to the mass ratio, and the part refers to the mass part.

[0097] In this article, when describing the embodiments or examples, it should be understood that it is not used to limit the present invention to these embodiments or examples. On the contrary, all alternatives, modifications and equivalents of the methods and materials described in the present invention can be covered within the scope defined by the claims.

[0098] In this article, for the sake of concise description, all possible combinations of all technical features in each embodiment or example are not described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope described in this specification.

[0099] In the present invention, the water is preferably deionized water.

[0100] The present invention uses a seed emulsion polymerization process to prepare a silicone-containing acrylate-styrene-acrylonitrile graft copolymer, which can better balance the impact toughness and surface gloss of the blended resin after being blended with the resin.

[0101] The present invention first prepares a polyacrylate seed latex. During the subsequent preparation of the large-particle-size polyacrylate latex, an active silicone oil and acrylate monomers are added. The active functional groups in the silicone oil and the acrylate monomers can copolymerize to form a random copolymer of acrylate containing organosilicon. The introduction of organosilicon can enhance the cohesion and erosion resistance stability of the acrylate rubber "core". The flexibility of the Si-O-Si bond provides an additional impact reinforcement effect, enabling the ASA resin to obtain sufficient impact strength even in the case of relatively small particle size, thus achieving the balance between toughness and appearance (surface gloss) and meeting the requirements during its applications in electronic appliances, automotive interior and exterior trims, etc.

[0102] In the present invention, the active silicone oil refers to a silicone oil containing multiple reactive vinyl groups.

[0103] In the preparation of the traditional ASA graft latex core, a crosslinking agent is often introduced. However, in the present invention, since the active silicone oil has multiple reactive functional groups and can act as a crosslinking agent, no additional crosslinking agent needs to be introduced in the polymerization process of the present invention, and the addition of polyfunctional acrylate crosslinking agents can be completely cancelled during the preparation.

[0104] In addition, since a polyorganosiloxane chain segment with a lower glass transition temperature (Tg) is introduced into the graft copolymer of the present invention, the impact resistance and low-temperature toughness of the blended resin of the present invention are improved.

[0105] In the present invention, vinyl silicone oil is directly introduced during the preparation of the core-shell graft copolymer. Compared with the method of directly polymerizing using siloxane monomers (such as octamethylcyclotetrasiloxane (D4), dodecamethylcyclohexasiloxane (D6), hexadecamethylcyclooctasiloxane (D8), etc.) in the prior art, the present invention does not need to recover the unreacted excess monomers. Compared with the method of first preparing a polysiloxane emulsion and then polymerizing with acrylate monomers in the prior art, the preparation process of the present invention is further simplified, the manufacturing cost is reduced, and the defect of difficult preparation of large-particle-size Si-PBA latex is also overcome.

[0106] In addition, the present invention uses a multi-step semi-continuous seed emulsion polymerization process to prepare the core-shell graft copolymer, and the particle size of the silicone-containing ASA core-shell graft copolymer can be controllably designed according to application requirements.

[0107] In this article, conversion refers to the transformation of reactive molecules into structural units of polymers through reactions.

[0108] The present invention provides a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer, its latex and a preparation method. The technological process for preparing the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex and the silicone acrylate-styrene-acrylonitrile copolymer blend resin includes: preparation of polyacrylate seed latex, preparation of large-particle-size silicone polyacrylate latex, preparation of silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex, preparation of silicone acrylate-styrene-acrylonitrile core-shell graft copolymer powder (silicone ASA powder), and blending of the silicone ASA powder with SAN resin to prepare the silicone acrylate-styrene-acrylonitrile copolymer blend resin (silicone ASA resin). In the first step, a small-particle-size polyacrylate seed latex with a particle size of 70-130 nm is prepared using acrylate monomers, grafting agents and crosslinking agents; in the second step, an appropriate amount of the small-particle-size polyacrylate latex is used as seeds, and a vinyl-functional silicone oil, acrylate monomers and grafting agents are added for emulsion polymerization to prepare a large-particle-size silicone polyacrylate latex with a particle size of 150-600 nm; in the third step, based on the presence of the large-particle-size silicone polyacrylate latex, vinyl aromatic monomers and vinyl acrylonitrile monomers are added for grafting reaction to prepare a silicone acrylate-styrene-acrylonitrile graft copolymer latex with a core-shell structure; in the fourth step, the graft copolymer latex is demulsified, coagulated and dried to obtain the graft copolymer powder; finally, the graft copolymer powder is blended with SAN resin to prepare the silicone ASA blend resin.

[0109] As Figure 1 shown, in some embodiments, the microstructure of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention sequentially includes a polyacrylate seed inner core 1, a polyacrylate seed outer core 2, a silicone polyacrylate inner core 3, a silicone polyacrylate outer core 4 and a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer shell 5 from the inside out, wherein Si-O-Si segments 6 exist in the silicone polyacrylate inner core 3 and the silicone polyacrylate outer core 4.

[0110] In the present invention, the polyacrylate seed inner core and the polyacrylate seed outer core are collectively referred to as the core part, the silicone polyacrylate inner core and the silicone polyacrylate outer core are collectively referred to as the core layer, and the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer shell is simply referred to as the shell layer.

[0111] In the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention, the mass ratio of the core part to the core layer can be (0.4-10):100, such as 0.5:100, 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100.

[0112] In the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention, the mass fraction of the shell layer in the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer can be 30% to 60%, such as 35%, 40%, 45%, 50%, 55%.

[0113] In the core layer of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention, the mass ratio of the structural unit converted from the vinyl-functionalized silicone oil to the structural unit converted from the acrylate monomer can be (0.5 to 10):100, such as 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100.

[0114] The vinyl content of the vinyl-functionalized silicone oil applicable to the present invention is 0.1 wt% to 5 wt%, preferably 0.5 wt% to 4 wt%, such as 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%.

[0115] The viscosity of the vinyl-functionalized silicone oil applicable to the present invention is 1 to 100 mm 2 / s, preferably 20 to 80 mm 2 / s, such as 30 mm 2 / s, 40 mm 2 / s, 50 mm 2 / s, 60 mm 2 / s, 70 mm 2 / s.

[0116] The weight-average molecular weight of the vinyl-functionalized silicone oil applicable to the present invention is 50 to 5000, preferably 500 to 4000, such as 1000, 1500, 2000, 2500, 3000, 3500.

[0117] The present invention finds that using a vinyl-functionalized silicone oil with a vinyl content of 0.1 wt% to 5 wt%, a viscosity of 1 to 100 mm 2 / s and a weight-average molecular weight of 50 to 5000 can make the reaction system of the vinyl-functionalized silicone oil and the acrylate monomer have good stability, enable the vinyl-functionalized silicone oil and the acrylate monomer to copolymerize well, improve the solid content of the reaction system and the particle size of the latex produced by the reaction, and the silicone oil active groups in the vinyl-functionalized silicone oil that meet the above requirements of vinyl content, viscosity and weight-average molecular weight have relatively high reactivity, and the distribution of Si-O-Si groups in the rubber prepared is better. Therefore, it can better improve the low-temperature impact resistance of the blended resin and further improve the surface gloss. The vinyl-functionalized silicone oil applicable to the present invention can be purchased through commercial channels.

[0118] In the core of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention, the mass ratio of the structural unit converted from the grafting agent to the structural unit converted from the acrylate monomer can be (0.2 to 5):100, such as 0.5:100, 1:100, 2:100, 3:100, 4:100.

[0119] In the core of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention, the mass ratio of the structural unit converted from the crosslinking agent to the structural unit converted from the acrylate monomer can be (0.2 to 5):100, such as 0.5:100, 1:100, 2:100, 3:100, 4:100.

[0120] In the core layer of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention, the mass ratio of the structural unit converted from the grafting agent to the structural unit converted from the acrylate monomer can be (0.2 to 2):100, such as 0.3:100, 0.5:100, 0.7:100, 0.8:100, 1:100, 1.5:100.

[0121] In the shell layer of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention, the mass fraction of the structural unit converted from the vinyl aromatic monomer in the shell layer can be 70% to 80%, such as 73%, 75%, 77%, and the mass fraction of the structural unit converted from the vinyl nitrile monomer in the shell layer can be 20% to 30%, such as 23%, 25%, 27%.

[0122] The diameter of the core of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention (corresponding to the particle size of the seed latex) can be 70 to 130 nm, such as 80 nm, 90 nm, 100 nm, 110 nm, 120 nm.

[0123] The diameter of the core layer of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer of the present invention (corresponding to the particle size of the silicone polyacrylate latex) can be 150 to 600 nm, such as 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm.

[0124] In the present invention, the acrylate monomer in the core and the acrylate monomer in the core layer can be the same or different. In some preferred embodiments, the acrylate monomer in the core and the acrylate monomer in the core layer are the same.

[0125] In the present invention, the grafting agent in the core and the grafting agent in the core layer can be the same or different. In some preferred embodiments, the grafting agent in the core and the grafting agent in the core layer are the same.

[0126] In the present invention, a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex can be prepared first, and then the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex is demulsified, cured, washed, and dried to obtain a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer.

[0127] The silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex can be prepared by a method including the following steps:

[0128] (1) In the presence of water, an emulsifier, an electrolyte, and a water-soluble initiator, an acrylate monomer, a grafting agent, and a crosslinking agent are reacted to form a core part, obtaining a seed latex;

[0129] (2) In the presence of water, an emulsifier, an electrolyte, and a water-soluble initiator, the seed latex obtained in step (1), an acrylate monomer, a grafting agent, and a vinyl-functional silicone oil are reacted to form a core layer on the surface of the core part, obtaining a silicone polyacrylate latex;

[0130] (3) In the presence of water, an emulsifier, an electrolyte, and an oil-soluble initiator, the silicone polyacrylate latex obtained in step (2), a vinyl aromatic monomer, and a vinyl nitrile monomer are reacted to form a shell layer on the surface of the core layer, obtaining a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex.

[0131] The emulsifiers used in step (1), step (2), and step (3) can be the same or different. In some embodiments, the emulsifiers used in step (1), step (2), and step (3) are the same. The water-soluble initiators used in step (1) and step (2) can be the same or different. In some embodiments, the water-soluble initiators used in step (1) and step (2) are the same.

[0132] In step (1), the mass ratio of water to the acrylate monomer can be (150-200):100, such as 160:100, 170:100, 180:100, 190:100.

[0133] In step (1), the mass ratio of the emulsifier to the acrylate monomer can be (0.5-3):100, such as 1:100, 1.5:100, 2:100, 2.5:100.

[0134] In step (1), the mass ratio of the electrolyte to the acrylate monomer can be (0.3-0.45):100, such as 0.35:100, 0.4:100.

[0135] In step (1), the mass ratio of the water-soluble initiator to the acrylate monomer can be (0.25 - 0.5):100, such as 0.3:100, 0.4:100.

[0136] In some preferred embodiments, in step (1), part of the acrylate monomer, part of the grafting agent, part of the crosslinking agent, part of the water-soluble initiator and part of the water are gradually added to the reaction system in the form of a first pre-emulsion during the reaction process, and the remaining raw materials are added to the reaction system before the start of the reaction. The mass of the acrylate monomer, grafting agent, crosslinking agent and water-soluble initiator in the first pre-emulsion is preferably 60% - 90% of the mass of the acrylate monomer, grafting agent, crosslinking agent and water-soluble initiator used in step (1), such as 65%, 70%, 75%, 80%, 85%. The mass of water in the first pre-emulsion can be 20% - 40% of the mass of water used in step (1), such as 25%, 30%, 35%. The first pre-emulsion is preferably added to the reaction system slowly (for example, over 3 - 4 h).

[0137] In step (1), the reaction temperature can be 70 - 80 °C, such as 75 °C. Step (1) is preferably reacted until the polymerization conversion rate ≥ 98%.

[0138] In step (2), the mass ratio of the added water to the added acrylate monomer can be (150 - 200):100, such as 160:100, 170:100, 180:100, 190:100.

[0139] In step (2), the mass ratio of the added emulsifier to the added acrylate monomer can be (0.5 - 3):100, such as 1:100, 1.5:100, 2:100, 2.5:100.

[0140] In step (2), the mass ratio of the added electrolyte to the added acrylate monomer can be (0.3 - 0.45):100, such as 0.35:100, 0.4:100.

[0141] In step (2), the mass ratio of the added water-soluble initiator to the added acrylate monomer can be (0.25 - 0.5):100, such as 0.3:100, 0.4:100.

[0142] In some preferred embodiments, in step (2), part of the acrylate monomers, part of the grafting agent, part of the vinyl-functional silicone oil, part of the water-soluble initiator, part of the emulsifier, and part of the water are gradually added to the reaction system in the form of a second pre-emulsion during the reaction process, and the remaining raw materials are added to the reaction system before the reaction starts. The mass of the acrylate monomers, grafting agent, vinyl-functional silicone oil, water-soluble initiator, and emulsifier in the second pre-emulsion is independently preferably 60% to 90% of the mass of the acrylate monomers, grafting agent, vinyl-functional silicone oil, water-soluble initiator, and emulsifier added in step (2), such as 65%, 70%, 75%, 80%, 85%. The mass of the water in the second pre-emulsion can be 20% to 40% of the mass of the water added in step (2), such as 25%, 30%, 35%. The second pre-emulsion is preferably added to the reaction system slowly (e.g., over 3 to 4 h).

[0143] In step (2), the reaction temperature is preferably 75 to 85 °C, such as 80 °C. Step (2) is preferably reacted until the polymerization conversion rate ≥ 98%.

[0144] In step (3), the ratio of the mass of the water added to the total mass of the silicon-containing polyacrylate latex dry matter, vinyl aromatic monomer, and vinyl nitrile monomer added can be (150 to 200):100, such as 160:100, 170:100, 180:100, 190:100.

[0145] In step (3), the ratio of the mass of the emulsifier added to the total mass of the silicon-containing polyacrylate latex dry matter, vinyl aromatic monomer, and vinyl nitrile monomer added can be (0.5 to 3):100, such as 1:100, 1.5:100, 2:100, 2.5:100.

[0146] In step (3), the ratio of the mass of the electrolyte added to the total mass of the silicon-containing polyacrylate latex dry matter, vinyl aromatic monomer, and vinyl nitrile monomer added can be (0.3 to 0.45):100, such as 0.35:100, 0.4:100.

[0147] In step (3), the ratio of the mass of the oil-soluble initiator added to the total mass of the silicon-containing polyacrylate latex dry matter, vinyl aromatic monomer, and vinyl nitrile monomer added can be (0.25 to 0.5):100, such as 0.35:100, 0.4:100.

[0148] In some preferred embodiments, in step (3), part of the vinyl aromatic monomer, part of the vinyl nitrile monomer, part of the oil-soluble initiator, part of the emulsifier and part of the water are gradually added to the reaction system in the form of a third pre-emulsion during the reaction process, and the remaining raw materials are added to the reaction system before the start of the reaction. The mass of the vinyl aromatic monomer, vinyl nitrile monomer, oil-soluble initiator and emulsifier in the third pre-emulsion is independently preferably 60% to 90%, such as 65%, 70%, 75%, 80%, 85% of the mass of the vinyl aromatic monomer, vinyl nitrile monomer, oil-soluble initiator and emulsifier added in step (3). The mass of water in the third pre-emulsion can be 20% to 40%, such as 25%, 30%, 35% of the mass of water added in step (3). The third pre-emulsion is preferably added to the reaction system slowly (for example, over 3 to 4 h).

[0149] In step (3), the reaction temperature is preferably 65 to 75 °C, such as 70 °C. Step (3) is preferably reacted until the polymerization conversion rate ≥ 98%.

[0150] The obtained silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex is demulsified, cured, washed and dried to obtain a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer. The silicone acrylate-styrene-acrylonitrile core-shell graft copolymer is usually in powder form and is also called silicone acrylate-styrene-acrylonitrile core-shell graft copolymer rubber powder.

[0151] The methods of demulsification, curing, washing and drying can be conventional. For example, an aqueous salt solution (such as an aqueous magnesium sulfate solution with a concentration of 5 wt%) can be added to the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex at 75 to 85 °C (such as 80 °C) for demulsification, and the mass ratio of the aqueous salt solution to the latex can be 3:1 to 1:3, such as 1:1. After demulsification, it is heated for curing. The curing temperature can be 90 to 100 °C, such as 95 °C, and the curing time can be 15 min to 60 min, such as 30 min. After curing, through washing, centrifugal dehydration and drying, the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer rubber powder can be obtained.

[0152] The silicone acrylate-styrene-acrylonitrile graft copolymer of the present invention is melt-blended with acrylonitrile-styrene copolymer to obtain a silicone acrylate-propylene-acrylonitrile copolymer blend resin. In the blend resin, the mass ratio of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer to the acrylonitrile-styrene copolymer can be 30:70 to 45:55, such as 35:65, 40:60. Appropriate additives, such as antioxidants and / or lubricants, can be added to the blend resin as needed. The dosage of each of the antioxidant and the lubricant usually does not exceed 0.5% of the total mass of the silicone acrylate-styrene-acrylonitrile graft copolymer and the acrylonitrile-styrene copolymer, such as 0.1%, 0.2%, 0.3%, 0.4%. The extrusion temperature can be 180-240°C.

[0153] In some embodiments, the method for preparing the silicone acrylate-styrene-acrylonitrile copolymer blend resin of the present invention comprises the following steps:

[0154] (1) Preparation of polyacrylate seed latex

[0155] After the reactor is purged with nitrogen, 15-25 parts (such as 20 parts) of acrylate monomer, 0.1-2 parts (such as 0.5-1 part) of grafting agent, 0.1-2 parts (such as 0.5-1 part) of crosslinking agent, 100-150 parts of water, 0.5-3 parts (such as 2-3 parts) of emulsifier, 0.3-0.45 parts of electrolyte and 0.05-0.1 part of water-soluble initiator are added. The temperature is raised to 70-80°C and reacted for 20-40 min (such as 30 min). Then, while maintaining the reaction temperature, the first pre-emulsion is added to the reactor within 3-4 h using a peristaltic pump. After addition, the reaction is carried out at a constant temperature for 1-2 h until the polymerization conversion rate ≥ 98%. The temperature is lowered to room temperature to stop the reaction, and polyacrylate seed latex with a particle size of 70-130 nm is prepared. The first pre-emulsion comprises 75-85 parts (such as 80 parts) of acrylate monomer, 0.1-3 parts (such as 1-2 parts) of grafting agent, 0.1-3 parts (such as 1-2 parts) of crosslinking agent, 0.2-0.4 part of water-soluble initiator and 50-100 parts of water. The total amount of acrylate monomers used in step (1) is 100 parts.

[0156] (2) Preparation of silicone-containing polyacrylate latex

[0157] After the reactor is purged with nitrogen, 0.5 - 10 parts (by dry matter weight) of the polyacrylate seed latex prepared in step (1), 15 - 25 parts (e.g., 20 parts) of acrylate monomers, 0.1 - 1 part (e.g., 0.2 - 0.4 parts) of grafting agent, 0.2 - 4 parts of vinyl-functional silicone oil, 100 - 150 parts of water, 0.25 - 1 part (e.g., 0.5 - 1 part) of emulsifier, 0.3 - 0.45 parts of electrolyte, and 0.05 - 0.1 part of water-soluble initiator are added. The temperature is raised to 75 - 85 °C and reacted for 20 - 40 min (e.g., 30 min). Then, while maintaining the reaction temperature, the second pre-emulsion is added to the reactor within 3 - 4 h using a peristaltic pump. After addition, the reaction is carried out at a constant temperature for 1 - 2 h until the polymerization conversion rate ≥ 98%. The temperature is then lowered to room temperature to stop the reaction, and a silicone-containing polyacrylate latex with a particle size of 150 - 600 nm is prepared. The second pre-emulsion includes 75 - 85 parts (e.g., 80 parts) of acrylate monomers, 0.1 - 1 part (e.g., 0.3 - 0.6 parts) of grafting agent, 0.3 - 6 parts of vinyl-functional silicone oil, 0.2 - 0.4 parts of water-soluble initiator, 0.25 - 2 parts (e.g., 1.5 - 2 parts) of emulsifier, and 50 - 100 parts of water. The total amount of acrylate monomers used in step (2) is 100 parts.

[0158] (3) Preparation of silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer latex

[0159] After the reactor is purged with nitrogen, 40 - 60 parts (by dry matter weight) of the silicone-containing polyacrylate latex prepared in step (2), 100 - 150 parts of water, 6 - 9 parts of vinyl aromatic monomers, 2 - 3 parts of vinyl nitrile monomers, 0.25 - 1 part (e.g., 0.5 - 1 part) of emulsifier, 0.3 - 0.45 parts of electrolyte, and 0.05 - 0.1 part of oil-soluble initiator are added. The temperature is raised to 65 - 75 °C and reacted for 20 - 40 min (e.g., 30 min). Then, while maintaining the reaction temperature, the third pre-emulsion is added to the reactor within 3 - 4 h using a peristaltic pump. After addition, the reaction is carried out at a constant temperature for 1 - 2 h until the polymerization conversion rate ≥ 98%. The temperature is then lowered to room temperature to stop the reaction, and a silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer latex is prepared. The third pre-emulsion includes 24 - 36 parts of vinyl aromatic monomers, 8 - 12 parts of vinyl nitrile monomers, 0.2 - 0.4 parts of oil-soluble initiator, 0.25 - 2 parts (e.g., 1.5 - 2 parts) of emulsifier, and 50 - 100 parts of water. The total amount of the dry matter of the silicone-containing polyacrylate latex, vinyl aromatic monomers, and vinyl nitrile monomers used in step (3) is 100 parts.

[0160] (4) Preparation of silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer powder

[0161] The aqueous salt solution is added to the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex prepared in step (3) at 75 °C to 85 °C (e.g., 80 °C) for demulsification, and then heated to 95 °C for curing. After washing, centrifugal dehydration and drying, the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer rubber powder is obtained.

[0162] (5) Preparation of silicone acrylate-styrene-acrylonitrile copolymer blend resin

[0163] Take 30 - 45 parts of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer rubber powder prepared in step (4), 55 - 70 parts of SAN resin, 0.2 - 0.5 parts of antioxidant and 0.2 - 0.5 parts of lubricant and blend them. Then, the silicone acrylate-styrene-acrylonitrile copolymer blend resin particles are prepared by granulation with a twin-screw extruder at 180 - 240 °C. The total amount of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer rubber powder and SAN resin used in step (5) is 100 parts.

[0164] The silicone acrylate-styrene-acrylonitrile core-shell graft copolymer and the silicone acrylate-styrene-acrylonitrile copolymer blend resin of the present invention can be added to plastics as modifiers, such as toughening agents. In the present invention, the matrix resins of plastics include but are not limited to polyvinyl chloride, polyamide, polycarbonate, polyoxymethylene, polyphenylene ether, polyester, polyimide, polyphenylene sulfide, polysulfone, polyether ether ketone, polyarylether ketone, fluororesin, etc. The polyamide can be polyethylene terephthalate, nylon, etc. In the present invention, the matrix resin of plastics refers to the resin component that accounts for the main mass of the plastic. For example, the mass of the matrix resin can be more than 50%, more than 60%, more than 70%, more than 80% or more than 90% of the mass of the plastic.

[0165] The present invention has achieved the following beneficial effects:

[0166] 1. The present invention creatively introduces an appropriate amount of vinyl-functional silicone oil in the step of preparing the large-particle-size silicone polyacrylate latex in the second step. The present invention finds that when the vinyl content of the vinyl-functional silicone oil is 0.1 wt% - 5 wt%, the viscosity is 1 - 100 mm 2 / s, and the weight-average molecular weight is 50 - 5000, the reactivity of the silicone oil active groups is relatively high, the distribution of Si-O-Si groups in the rubber is better, and it can better improve the low-temperature impact resistance of the blended resin and further improve the surface gloss.

[0167] 2. The present invention adopts a multi-step semi-continuous emulsion polymerization process in the preparation of the silicone ASA core-shell graft copolymer, and the particle size of the prepared silicone polyacrylate latex can be adjusted. There is a four-layer core-shell structure with different crosslinking degrees in the rubber layer, which can better improve the impact resistance of the blended resin and has good processing performance.

[0168] 3. The advantages of the present invention also lie in that due to the introduction of the vinyl-functional group-containing silicone oil, it can replace the role of acrylate crosslinking agents in traditional acrylate polymerization, and the introduction of acrylate crosslinking agents can be avoided.

[0169] 4. By introducing a vinyl-functional group-containing silicone oil (requiring a certain viscosity, vinyl content, and molecular weight) during the preparation of the large-particle-size silicone-containing polyacrylate latex, the present invention obtains a silicone-modified ASA resin with a balance of impact toughness and gloss.

[0170] 5. Different from the traditional process in which silane reaction needs to be introduced during the preparation of silicone-containing polyacrylate rubber, the present invention further simplifies the process. The traditional method is as follows: First, emulsion polymerization is used to synthesize a crosslinked silicone rubber as a seed emulsion, and then a pre-emulsion containing organosiloxane and acrylate monomers is continuously added dropwise to prepare an elastomer emulsion with an interpenetrating network structure of a silicone-acrylate structure. At this stage, due to the excessive addition amount of organosiloxane or too high silicon content, it is easy to form gels; in addition, during the polymerization process, organosiloxane is likely to form long-chain macromolecular structures, which are difficult to control and cause demulsification; moreover, the surface energy of organosiloxane is relatively low, and it is difficult to be emulsified in emulsion polymerization and difficult to enter the micelles, thus limiting the copolymerization of organosiloxane and acrylate monomers. This is also the difficulty in preparing Si-PBA emulsion by organosiloxane modification; in order to maintain the stability of the emulsion, the solid content of the traditional reaction system is generally low, and the particle size of the rubber phase is mostly less than 100 nm. By optimizing the vinyl-functional group-containing silicone oil (requiring a certain viscosity, vinyl content, and molecular weight), the present invention solves the problem of system stability. Therefore, the solid content and the particle size of the rubber phase have no difference from those of traditional ASA.

[0171] The present invention will be described below by way of specific examples. It should be understood that these examples are only illustrative and are not intended to limit the scope of the present invention. The methods, reagents, and materials used in the examples are conventional methods, reagents, and materials in the art unless otherwise specified. The raw material compounds in the examples can be obtained through commercial channels. The feeding parts in the examples and comparative examples are all in parts by mass.

[0172] The sources of the bis-terminal vinyl silicone oil and the terminal-side vinyl silicone oil used in the examples and comparative examples are as follows:

[0173] Bis-terminal vinyl silicone oil A (viscosity: 40 mm 2 / s, vinyl content: 2%, Mw: 3000) was purchased from Zhonglan Chenguang Research and Design Institute of Chemical Industry, with the brand number 40 cs, and the chemical structure is as shown in Formula I above.

[0174] Terminal-side vinyl silicone oil (viscosity: 35 mm 2 / s, vinyl content: 3%, Mw: 2800) was purchased from Zhonglan Chenguang Research and Design Institute of Chemical Industry, grade 35cs, and its chemical structure is as shown in Formula II above.

[0175] Bifunctional vinyl silicone oil B (viscosity: 200 mm 2 / s, vinyl content: 0.5%, Mw: 7000) was purchased from Zhonglan Chenguang Research and Design Institute of Chemical Industry, grade 200cs, and its chemical structure is as shown in Formula I above.

[0176] The test methods involved in the examples and comparative examples are as follows:

[0177] (1) Particle size: The average size was measured by dynamic light scattering using a Litesizer particle size analyzer from Anton Paar.

[0178] (2) Polymerization conversion rate: Take 5 g of the prepared latex and transfer it to a moisture analyzer from Sartorius to measure the total solid content (TSC). The polymerization conversion rate was calculated using the following formula.

[0179] Polymerization conversion rate = [(measured total solid content - solid content of added auxiliary materials) / (theoretical total solid content of the system - other than the solid content of added auxiliary materials)] * 100%.

[0180] (3) Gel bleeding rate: Cut a filter screen of appropriate size (200 mesh), dry it and weigh it as m1, then cover it on the sample bottle mouth. Transfer the latex in the reactor through the filter screen into the sample bottle, and scrape the gel bleeding at the reactor bottle wall and the stirring paddle onto the filter screen. Then rinse the filter screen with water until the liquid is clear, transfer it to a blast drying oven and dry it at 80 °C to constant weight, and weigh its mass as m2. Gel bleeding rate = (m2 - m1) / total formula mass * 100%.

[0181] (4) Impact strength at normal temperature and low temperature: Tested according to the standard of GB / T 1843-2008 "Determination of Izod impact strength", and expressed in units of kilojoules per square meter (KJ / m 2 ) When measuring the low-temperature impact strength, the specimen was kept at -30 °C for 48 hours and then the Izod notched impact strength was measured.

[0182] (5) Surface glossiness: Measured the surface glossiness of the specimen at 60° according to the standard of GB / T 8807-1998 "Test method for specular gloss of plastics".

[0183] (6) Melt index: Measured the melt flow index of the prepared pellets at 220 °C and 10 kg according to GB / T 3682.1-2018. The unit of the melt flow index is g / 10min.

[0184] (7) Vinyl content of the silicone oil with vinyl functional groups: Prepare a mixed solution of the sample and the standard sample with a deuterated reagent, conduct a nuclear magnetic resonance hydrogen spectrum test, and calculate the relative content of vinyl through the proportional relationship between the standard sample and the characteristic peaks of the silicone oil.

[0185] (8) Viscosity of the silicone oil with vinyl functional groups: Test according to the standard of HG / T 2363-1992 "Test Method for Kinematic Viscosity of Silicone Oil".

[0186] (9) Weight-average molecular weight (Mw) of the silicone oil with vinyl functional groups: Dissolve the silicone oil sample in tetrahydrofuran, use polystyrene (PS) with different molecular weights as the standard sample, and test the weight-average molecular weight of the sample with a GPC instrument.

[0187] Example 1

[0188] (1) Preparation of small-particle-size polyacrylate seed latex

[0189] After purging the reaction kettle with nitrogen, add 20 parts of n-butyl acrylate, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 100 parts of deionized water, 3 parts of sodium dodecyl sulfate, 0.35 part of sodium bicarbonate, and 0.05 part of potassium persulfate, and raise the temperature to 80 °C for reaction for 30 min. Keep the reaction temperature, add the first pre-emulsion to the reaction kettle within 4 h with a peristaltic pump, keep the temperature constant for reaction for 2 h after addition, the polymerization conversion rate reaches 98%, cool down to room temperature and stop the reaction to prepare a small-particle-size polyacrylate seed latex. The first pre-emulsion includes 80 parts of n-butyl acrylate, 1.5 parts of allyl methacrylate, 1.5 parts of ethylene glycol dimethacrylate, 0.2 part of potassium persulfate, and 50 parts of deionized water.

[0190] (2) Preparation of large-particle-size silicone-containing polyacrylate latex

[0191] After purging the reaction kettle with nitrogen, put 3 parts (calculated by mass in dry weight) of the small-particle-size polyacrylate seed latex prepared in step (1), 20 parts of n-butyl acrylate, 0.2 part of allyl methacrylate, double-end vinyl silicone oil A (viscosity: 40 mm 2 / s, vinyl content: 2%, Mw: 3000) 0.8 part, 100 parts of deionized water, 0.5 part of sodium dodecyl sulfate, 0.35 part of sodium bicarbonate, and 0.05 part of potassium persulfate, and raise the temperature to 80 °C for reaction for 30 min. Keep the reaction temperature, add the second pre-emulsion to the reaction kettle within 4 h with a peristaltic pump, keep the temperature constant for reaction for 2 h after addition, the polymerization conversion rate reaches 98%, cool down to room temperature and stop the reaction to prepare a large-particle-size silicone-containing polyacrylate latex. The second pre-emulsion includes 80 parts of n-butyl acrylate, 0.3 part of allyl methacrylate, double-end vinyl silicone oil A (viscosity: 40 mm 2 / s, vinyl content: 2%, Mw: 3000) 1.2 parts, potassium persulfate 0.2 parts, sodium dodecyl sulfate 2 parts and deionized water 50 parts.

[0192] (3) Preparation of silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex

[0193] After purging the reactor with nitrogen, 60 parts (by mass fraction based on dry weight) of the large-particle-size silicone-containing poly(n-butyl acrylate) latex prepared in step (2), 100 parts of deionized water, 6 parts of styrene, 2 parts of acrylonitrile, 0.5 part of sodium dodecyl sulfate, 0.35 part of sodium bicarbonate and 0.05 part of cumene hydroperoxide were added, and the temperature was raised to 70 °C and reacted for 30 min. While maintaining the reaction temperature, the third pre-emulsion was added to the reactor within 4 h using a peristaltic pump, and after addition, the reaction was carried out at a constant temperature for 2 h. When the polymerization conversion reached 98%, the temperature was lowered to room temperature to stop the reaction, and a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex was prepared. The third pre-emulsion includes 24 parts of styrene, 8 parts of acrylonitrile, 0.2 part of cumene hydroperoxide, 2 parts of sodium dodecyl sulfate and 50 parts of deionized water.

[0194] (4) Preparation of silicone acrylate-styrene-acrylonitrile core-shell graft copolymer powder

[0195] 100 parts of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex prepared in step (3) and 100 parts of deionized water were added to a reactor and heated to 80 °C, then 40 parts of a 5 wt% aqueous solution of magnesium sulfate was added for demulsification, and the temperature was raised to 95 °C and cured for 30 min. After washing, centrifugal dehydration and drying, a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer powder (i.e., silicone-containing ASA powder) was obtained.

[0196] (5) Preparation of silicone acrylate-styrene-acrylonitrile copolymer blend resin

[0197] 30 parts of the silicone-containing ASA powder prepared in step (4), 70 parts of SAN resin (Taiwan Chemical Fiber NF2200), 0.2 part of antioxidant 1010 (pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]) and 0.4 part of lubricant ethylene bisstearamide were blended, and then granulated by a twin-screw extruder at 180 - 240 °C to obtain silicone acrylate-styrene-acrylonitrile copolymer blend resin (i.e., silicone-containing ASA resin) particles. After drying, test specimens were prepared by an injection molding machine.

[0198] Example 2

[0199] The difference between Example 2 and Example 1 is that in the preparation of the large-particle-size silicone-containing polyacrylate latex in step (2), bis-end vinyl silicone oil A (viscosity: 40 mm 2The dosage of (viscosity: 35 mm

[0200] Example 3

[0201] The difference between Example 3 and Example 1 is that in the preparation of the large-particle-size silicone-containing polyacrylate latex in step (2), the dosage of the small-particle-size polyacrylate seed latex prepared in step (1) is adjusted to 2 parts (parts by mass calculated on a dry weight basis). The rest is prepared according to the same steps as in Example 1.

[0202] Example 4

[0203] The difference between Example 4 and Example 1 is that in the preparation of the large-particle-size silicone-containing polyacrylate latex in step (2), the dosage of the small-particle-size polyacrylate seed latex prepared in step (1) is adjusted to 8 parts (parts by mass calculated on a dry weight basis). The rest is prepared according to the same steps as in Example 1.

[0204] Example 5

[0205] The difference between Example 5 and Example 1 is that in the preparation of the large-particle-size silicone-containing polyacrylate latex in step (2), 2 parts of end-side vinyl silicone oil (viscosity: 35 mm 2 / s, vinyl content: 3%, Mw: 2800) is used to replace 2 parts of double-end vinyl silicone oil A, of which 0.8 part is added before the start of the reaction and 1.2 parts are added through the second pre-emulsion. The rest is prepared according to the same steps as in Example 1.

[0206] Comparative Example 1

[0207] The difference between Comparative Example 1 and Example 1 is that in the preparation of the large-particle-size silicone-containing polyacrylate latex in step (2), 2 parts of ethylene glycol dimethacrylate are used to replace 2 parts of double-end vinyl silicone oil A, of which 0.8 part is added before the start of the reaction and 1.2 parts are added through the second pre-emulsion. The rest is prepared according to the same steps as in Example 1.

[0208] Comparative Example 2

[0209] The difference between Comparative Example 2 and Example 1 is that in the preparation of the large-particle-size silicone-containing polyacrylate latex in step (2), the dosage of double-end vinyl silicone oil A (viscosity: 40 mm 2 / s, vinyl content: 2%, Mw: 3000) is adjusted to 12 parts, of which 4.8 parts are added before the start of the reaction and 7.2 parts are added through the second pre-emulsion. The rest is prepared according to the same steps as in Example 1. It is found that more latex coagulation occurs.

[0210] Comparative Example 3

[0211] The difference between Comparative Example 3 and Example 1 lies in that in the preparation of the large-particle-size silicone-containing polyacrylate latex in step (2), the double-ended vinyl silicone oil A (viscosity: 40 mm 2 / s, vinyl content: 2%, Mw: 3000) was replaced with double-ended vinyl silicone oil B (viscosity: 200 mm 2 / s, vinyl content: 0.5%, Mw: 7000), and the addition amount and addition method of the double-ended vinyl silicone oil remained unchanged. The rest was prepared according to the same steps as in Example 1.

[0212] Test Example

[0213] The particle size, polymerization conversion rate, and latex separation rate of the large-particle-size silicone-containing polyacrylate latex (large-particle-size PBA latex) and the silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer latex (silicone-containing ASA latex) in Examples 1-5 and Comparative Examples 1-3 were tested, and the results are shown in Table 1.

[0214] The low-temperature impact strength, normal-temperature impact strength, surface gloss, and melt index of the silicone-containing acrylate-styrene-acrylonitrile copolymer blend resin (silicone-containing ASA resin) in Examples 1-5 and Comparative Examples 1-3 were tested, and the results are shown in Table 1.

[0215] Table 1: Test results of latex and resin

[0216]

[0217]

[0218] As shown in Table 1, by selecting multi-vinyl silicone oil with appropriate viscosity, vinyl content, and molecular weight, the latex prepared in Examples 1-5 of the present invention has appropriate particle size and high conversion rate. The particle size of the prepared large-particle-size silicone-containing polyacrylate latex can be adjusted. The prepared silicone-containing ASA resin has high notched normal-temperature impact, good low-temperature strength (-30°C) retention, and a better increase in gloss. If the properties of the multi-vinyl silicone oil used are not within the range required by the present invention, more latex will precipitate, and the final reaction with the acrylate polymer will be less, and the low-temperature notched impact strength will also be low.

[0219] It can also be seen from Table 1 that in the preparation of the large-particle-size silicone-containing polyacrylate latex, when the dosage of the multi-vinyl silicone oil is within the range required by the present invention, the relevant properties are better. Excessive dosage will lead to a decrease in latex stability and more precipitation.

Claims

1. A silicone acrylate-styrene-acrylonitrile core-shell graft copolymer, characterized in that, the microstructure of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer sequentially includes a core part, a core layer and a shell layer from the center to the periphery; wherein, the core part includes structural units converted from acrylate monomers, structural units converted from grafting agents and structural units converted from crosslinking agents; the core layer includes structural units converted from acrylate monomers, structural units converted from grafting agents and structural units converted from vinyl-functionalized silicone oil; the shell layer includes structural units converted from vinyl aromatic monomers and structural units converted from vinyl nitrile monomers; the mass ratio of the core part to the core layer is (0.4 - 10):100; the mass fraction of the shell layer in the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer is 30% - 60%; in the core layer, the mass ratio of the structural units converted from vinyl-functionalized silicone oil to the structural units converted from acrylate monomers is (0.5 - 10):100; the vinyl-functionalized silicone oil is selected from one or more of a bis-terminal vinyl silicone oil having the structure shown in Formula I and a terminal-side vinyl silicone oil having the structure shown in Formula II. In Formula I and Formula II, a, n and m represent the number of repeating units:

2. The silicone acrylate-styrene-acrylonitrile core-shell graft copolymer according to claim 1, characterized in that, the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer has one or more of the following characteristics: the vinyl content of the vinyl-functionalized silicone oil is 0.1 wt% - 5 wt%, preferably 0.5 wt% - 4 wt%; The viscosity of the vinyl-functional silicone oil is 1 to 100 mm 2 / s, preferably 20 to 80 mm 2 / s; the weight-average molecular weight of the vinyl-functionalized silicone oil is 50 - 5000, preferably 500 - 4000; The acrylate monomer in the core part and the acrylate monomer in the core layer are each independently one or more acrylate alkyl esters with the structural formula CH 2 =CHCOOR, where R is a C1-C15 alkyl group, preferably a C1-C4 linear alkyl group; preferably, the acrylate monomer in the core part and the acrylate monomer in the core layer are each independently selected from one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylbutyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, hexyl acrylate, heptyl acrylate, n-pentyl acrylate, and lauryl acrylate; preferably, the acrylate monomer in the core part and the acrylate monomer in the core layer are butyl acrylate; the grafting agents in the core part and the grafting agents in the core layer are each independently one or more compounds containing two or more different unsaturated vinyl functional groups; preferably, the grafting agents in the core part and the grafting agents in the core layer are each independently selected from one or more of allyl methacrylate, triallyl isocyanurate, triallylamine and diallylamine; preferably, the grafting agents in the core part and the grafting agents in the core layer are allyl methacrylate; the crosslinking agent is one or more compounds containing two or more identical unsaturated vinyl functional groups; preferably, the crosslinking agent is selected from one or more of ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate and 1,3-propanediol diacrylate; preferably, the crosslinking agent is ethylene glycol dimethacrylate; the vinyl aromatic monomer is selected from one or more of styrene, α-methylstyrene and p-methylstyrene, preferably styrene; the vinyl nitrile monomer is selected from one or two of acrylonitrile and methacrylonitrile, preferably acrylonitrile; In the core part, the mass ratio of the structural unit converted from the grafting agent to the structural unit converted from the acrylate monomer is (0.2 - 5):100; In the core part, the mass ratio of the structural unit converted from the crosslinking agent to the structural unit converted from the acrylate monomer is (0.2 - 5):100; In the core layer, the mass ratio of the structural unit converted from the grafting agent to the structural unit converted from the acrylate monomer is (0.2 - 2):100; The mass fraction of the structural unit converted from the vinyl aromatic monomer in the shell layer is 70% - 80%, and the mass fraction of the structural unit converted from the vinyl nitrile monomer in the shell layer is 20% - 30%; The diameter of the core part is 70 - 130 nm; The diameter of the core layer is 150 - 600 nm.

3. A silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex, characterized in that, The silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex is an aqueous dispersion of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer described in claim 1 or 2.

4. A method for preparing the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer described in claim 1 or 2 or the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex described in claim 3, characterized in that, The method comprises the following steps: (1) In the presence of water, an emulsifier, an electrolyte and a water-soluble initiator, reacting an acrylate monomer, a grafting agent and a crosslinking agent to form a core part to obtain a seed latex; (2) In the presence of water, an emulsifier, an electrolyte and a water-soluble initiator, reacting the seed latex obtained in step (1), an acrylate monomer, a grafting agent and a vinyl-functional silicone oil to form a core layer on the surface of the core part to obtain a silicone polyacrylate latex; (3) In the presence of water, an emulsifier, an electrolyte and an oil-soluble initiator, reacting the silicone polyacrylate latex obtained in step (2), a vinyl aromatic monomer and a vinyl nitrile monomer to form a shell layer on the surface of the core layer to obtain a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex.

5. The method for preparing a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer or a silicone acrylate-styrene-acrylonitrile core-shell graft copolymer latex as described in claim 4, characterized in that, The method has one or more of the following characteristics: The emulsifiers in step (1), step (2) and step (3) are each independently selected from one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfate, sodium octadecyl sulfate, sodium oleate, potassium dodecyl sulfate, potassium dodecylbenzene sulfate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium oleate, potassium dodecylbenzenesulfonate, potassium octadecyl sulfate, potassium rosin and potassium oleate, preferably sodium dodecyl sulfate; The electrolytes in step (1), step (2) and step (3) are each independently selected from one or more of sodium chloride, potassium chloride, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate, preferably sodium bicarbonate; The water-soluble initiator in step (1) and step (2) is selected from one or more of sodium persulfate, potassium persulfate, ammonium persulfate, potassium peroxophosphate, and hydrogen peroxide, and preferably potassium persulfate; The oil-soluble initiator in step (3) is selected from one or more of tert-butyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, benzoyl peroxide, diisopropylbenzene hydroperoxide, 3,5,5-trimethylhexanol peroxide, tert-butyl peroxymethyl isobutyrate, azobisisobutyronitrile, azo-bis(2,4-dimethylvaleronitrile), azobiscyclohexanecarbonitrile, and azobis(isobutyric acid methyl ester), and preferably cumene hydroperoxide; The particle size of the seed latex is 70 - 130 nm; The particle size of the silicon-containing polyacrylate latex is 150 - 600 nm; In step (1), the mass ratio of water to the acrylate monomer is (150 - 200):100; In step (1), the mass ratio of the emulsifier to the acrylate monomer is (0.5 - 3):100; In step (1), the mass ratio of the electrolyte to the acrylate monomer is (0.3 - 0.45):100; In step (1), the mass ratio of the water-soluble initiator to the acrylate monomer is (0.25 - 0.5):100; In step (1), part of the acrylate monomer, part of the grafting agent, part of the crosslinking agent, part of the water-soluble initiator, and part of the water are gradually added to the reaction system in the form of a first pre-emulsion during the reaction process. The masses of the acrylate monomer, grafting agent, crosslinking agent, and water-soluble initiator in the first pre-emulsion are 60% - 90% of the masses of the acrylate monomer, grafting agent, crosslinking agent, and water-soluble initiator used in step (1) respectively; In step (1), the reaction temperature is 70 - 80 °C, and the reaction proceeds until the polymerization conversion rate ≥ 98%; In step (2), the mass ratio of the added water to the acrylate monomer is (150 - 200):100; In step (2), the mass ratio of the emulsifier to the acrylate monomer is (0.5 - 3):100; In step (2), the mass ratio of the electrolyte to the acrylate monomer is (0.3 - 0.45):100; In step (2), the mass ratio of the water-soluble initiator to the acrylate monomer is (0.25 - 0.5):100; In step (2), part of the acrylate monomer, part of the grafting agent, part of the vinyl-functional silicone oil, part of the water-soluble initiator, part of the emulsifier, and part of the water are gradually added to the reaction system in the form of a second pre-emulsion during the reaction process. The masses of the acrylate monomer, grafting agent, vinyl-functional silicone oil, water-soluble initiator, and emulsifier in the second pre-emulsion are 60% - 90% of the masses of the acrylate monomer, grafting agent, vinyl-functional silicone oil, water-soluble initiator, and emulsifier used in step (2) respectively; In step (2), the reaction temperature is 75 - 85 °C, and the reaction proceeds until the polymerization conversion rate ≥ 98%; In step (3), the mass ratio of the added water to the total mass of the dry matter of the silicone-containing polyacrylate latex, the vinyl aromatic monomer, and the vinyl cyanide monomer is (150 - 200):100; In step (3), the mass ratio of the emulsifier to the total mass of the dry matter of the silicone-containing polyacrylate latex, the vinyl aromatic monomer, and the vinyl cyanide monomer is (0.5 - 3):100; In step (3), the mass ratio of the electrolyte to the total mass of the dry matter of the silicone-containing polyacrylate latex, the vinyl aromatic monomer, and the vinyl cyanide monomer is (0.3 - 0.45):100; In step (3), the mass ratio of the oil-soluble initiator to the total mass of the dry matter of the silicone-containing polyacrylate latex, the vinyl aromatic monomer, and the vinyl cyanide monomer is (0.25 - 0.5):100; In step (3), part of the vinyl aromatic monomer, part of the vinyl cyanide monomer, part of the oil-soluble initiator, part of the emulsifier, and part of the water are gradually added to the reaction system in the form of a third pre-emulsion during the reaction. The masses of the vinyl aromatic monomer, vinyl cyanide monomer, oil-soluble initiator, and emulsifier in the third pre-emulsion are 60% - 90% of the masses of the vinyl aromatic monomer, vinyl cyanide monomer, oil-soluble initiator, and emulsifier used in step (3), respectively; In step (3), the reaction temperature is 65 - 75 °C, and the reaction is carried out until the polymerization conversion rate ≥ 98%.

6. The method for preparing a silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer or a silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer latex according to claim 4, wherein, Step (1) includes: adding an acrylate monomer, a grafting agent, a cross-linking agent, water, an emulsifier, an electrolyte, and a water-soluble initiator to a reactor, heating to 70 - 80 °C and reacting for 20 - 40 min, then maintaining the reaction temperature, adding the first pre-emulsion to the reactor within 3 - 4 h, and after adding, reacting at a constant temperature for 1 - 2 h until the polymerization conversion rate ≥ 98%, and stopping the reaction to obtain a seed latex; wherein the first pre-emulsion includes an acrylate monomer, a grafting agent, a cross-linking agent, a water-soluble initiator, and water. The masses of the acrylate monomer, grafting agent, cross-linking agent, and water-soluble initiator in the first pre-emulsion are 60% - 90% of the masses of the acrylate monomer, grafting agent, cross-linking agent, and water-soluble initiator used in step (1), respectively; Step (2) includes: adding the seed latex obtained in step (1), acrylate monomers, grafting agents, vinyl-functional silicone oil, water, emulsifiers, electrolytes, and water-soluble initiators into the reactor, heating to 75 - 85 °C and reacting for 20 - 40 min, then maintaining the reaction temperature, adding the second pre-emulsion into the reactor within 3 - 4 h, and after adding, reacting at a constant temperature for 1 - 2 h until the polymerization conversion rate ≥ 98%, stopping the reaction to obtain a silicone-containing polyacrylate latex, wherein the second pre-emulsion includes acrylate monomers, grafting agents, vinyl-functional silicone oil, water-soluble initiators, emulsifiers, and water, and the masses of acrylate monomers, grafting agents, vinyl-functional silicone oil, water-soluble initiators, and emulsifiers in the second pre-emulsion are 60% - 90% of the masses of acrylate monomers, grafting agents, vinyl-functional silicone oil, water-soluble initiators, and emulsifiers used in step (2); Step (3) includes: adding the silicone-containing polyacrylate latex obtained in step (2), water, vinyl aromatic monomers, vinyl nitrile monomers, emulsifiers, electrolytes, and oil-soluble initiators into the reactor, heating to 65 - 75 °C and reacting for 20 - 40 min, then maintaining the reaction temperature, adding the third pre-emulsion into the reactor within 3 - 4 h, and after adding, reacting at a constant temperature for 1 - 2 h until the polymerization conversion rate reaches ≥ 98%, stopping the reaction to prepare a silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer latex, wherein the third pre-emulsion includes vinyl aromatic monomers, vinyl nitrile monomers, oil-soluble initiators, emulsifiers, and water, and the masses of vinyl aromatic monomers, vinyl nitrile monomers, oil-soluble initiators, and emulsifiers in the third pre-emulsion are 60% - 90% of the masses of vinyl aromatic monomers, vinyl nitrile monomers, oil-soluble initiators, and emulsifiers used in step (3).

7. The method for preparing a silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer according to claim 4, characterized in that, the method further includes the following steps: (4) Demulsifying, curing, washing, and drying the silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer latex obtained in step (3) to obtain a silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer.

8. A silicone-containing acrylate-styrene-acrylonitrile copolymer blend resin, characterized in that, the silicone-containing acrylate-styrene-acrylonitrile copolymer blend resin comprises the silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer according to claim 1 or 2 and an acrylonitrile-styrene copolymer; Preferably, in the silicone-containing acrylate-styrene-acrylonitrile copolymer blend resin, the mass ratio of the silicone-containing acrylate-styrene-acrylonitrile core-shell graft copolymer to the acrylonitrile-styrene copolymer is 30:70 to 45:55; Preferably, the silicone acrylate-styrene-acrylonitrile copolymer blend resin further comprises an antioxidant and / or a lubricant. Based on the total mass of 100 parts by mass of the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer and the acrylonitrile-styrene copolymer, the mass of the antioxidant is 0.2-0.5 parts by mass, and the mass of the lubricant is 0.2-0.5 parts by mass; Preferably, the silicone acrylate-styrene-acrylonitrile copolymer blend resin is prepared by blending and extruding a raw material composition comprising the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer and the acrylonitrile-styrene copolymer; preferably, the extrusion temperature is 180-240 °C.

9. Use of a vinyl-functional silicone oil in the preparation of an acrylate-styrene-acrylonitrile core-shell graft copolymer, characterized in that, the vinyl-functional silicone oil is selected from one or more of a double-end vinyl silicone oil having the structure shown in Formula I and a terminal-side vinyl silicone oil having the structure shown in Formula II. In Formula I and Formula II, a, n, and m represent the number of repeating units: The vinyl content of the vinyl-functional silicone oil is 0.1 wt% to 5 wt%, the viscosity is 1 to 100 mm 2 / s, and the weight-average molecular weight is 50 - 5000; Preferably, the vinyl content of the vinyl-functional silicone oil is 0.5 wt% to 4 wt%; Preferably, the viscosity of the vinyl-functional silicone oil is 20 to 80 mm 2 / s; Preferably, the weight-average molecular weight of the vinyl-functional silicone oil is 500 to 4000.

10. A plastic comprising the silicone acrylate-styrene-acrylonitrile core-shell graft copolymer according to claim 1 or 2 or the silicone acrylate-styrene-acrylonitrile copolymer blend resin according to claim 8; Preferably, the matrix resin of the plastic is polyvinyl chloride, polyamide, polycarbonate, polyoxymethylene, polyphenylene ether, polyester, polyimide, polyphenylene sulfide, polysulfone, polyether ether ketone, polyarylether ketone or fluororesin.

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