Acrylate-styrene-acrylonitrile core-shell graft copolymer and latex and preparation method thereof

Abstract

The invention provides an acrylate-styrene-acrylonitrile core-shell graft copolymer, latex thereof and a preparation method. The preparation method of the acrylate-styrene-acrylonitrile core-shell grafted copolymer latex comprises the following steps: (1) in a reaction system containing an acrylate monomer, an emulsifier, a water-soluble initiator and water, carrying out polymerization reaction on the acrylate monomer to prepare seed latex; (2) dropwise adding the first-stage pre-emulsion into the seed latex, and carrying out diameter expansion reaction to prepare diameter-expanded latex; and (3) dropwise adding the second-stage pre-emulsion into the expanded latex, and carrying out a grafting reaction to prepare the acrylate-styrene-acrylonitrile core-shell grafted copolymer latex. The preparation method disclosed by the invention is simple in flow, few in working procedures, high in production efficiency and good in polymerization system stability, and the prepared resin is good in performance and quality.

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, its latex and a preparation method thereof. Background Art

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

[0003] ASA core-shell graft copolymer has two main uses. First, it is used as a toughening and modifying agent to modify and enhance polyvinyl chloride, polycarbonate, polyethylene terephthalate, nylon, etc. Second, it is blended with acrylonitrile-styrene copolymer (SAN) resin to make ASA resin, which is mainly 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] The preparation of ASA graft latex usually adopts the seed emulsion polymerization process, with more production steps and longer reaction time for each step. Each step of the reaction requires a specific polymerization reactor and latex storage tank. During the preparation of ASA graft latex, various polymerization aids are often added, especially an oil-soluble initiator system, and usually an activation system is also introduced. Although the introduction of the aids improves the stability of the polymerization reaction, it often increases the production cost and operation steps, and the added aids are difficult to completely remove, ultimately resulting in the deterioration of the resin appearance and the reduction of weather resistance.

[0005] CN104231185B prepares ASA graft latex by the seed emulsion polymerization process. First, acrylate seed latex is prepared by reacting for 4 - 5 h, then acrylate monomers, emulsifiers, initiators and diameter-expanding agents (such as trisodium sulfate, sodium chloride, potassium chloride, sodium sulfate, etc.) are added to react for 4 - 5 h to prepare core layer latex. Finally, a mixture of styrene and acrylonitrile monomers is added in two batches to react for more than 3 h to prepare ASA graft latex, and finally the graft copolymer is blended with SAN resin to prepare ASA resin. And an activation solution is introduced during the preparation of the ASA graft copolymer graft emulsion.

[0006] CN109071737B prepares an ASA graft copolymer by the seed emulsion polymerization process. To improve thermal stability by reducing unwanted residues remaining in the latex and at the same time excellently maintain the inherent properties of the ASA resin (latex stability, graft latex particle size around 380 nm), such as weather resistance, chemical resistance, and mechanical strength, and thereby reduce the amount of gas generated on the resin surface during the high-temperature thermoforming process, a small amount of emulsifier (0.5 - 0.83 parts, 100 parts of seed monomer, particle size 150 nm) is added in the seed preparation step; in the shell preparation step, a polyfunctional carboxylic acid or its salt having more than 20 carbon atoms is added as an emulsifier, and an activation solution is introduced.

[0007] CN113461864A prepares ASA graft rubber powder by the seed method. An emulsifier is added in the seed stage, and no emulsifier is added in the diameter expansion and grafting stages, reducing the generation of new micelles, making the reaction more stable, and being conducive to the growth of latex particle size and obtaining a narrower particle size distribution.

[0008] CN101307121B invents a method for preparing an impact-resistant polymer to address the problems of complex synthesis process, many materials used, and low efficiency in production practice for acrylate impact modifiers. The acrylate latex is prepared by the seed emulsion polymerization method, in which the addition of raw materials is divided into three stages during the preparation of the acrylate latex, and the preparation time is about 3.5 - 5.5 h; then styrene and acrylonitrile are introduced for grafting to prepare the ASA latex, in which the grafting process is divided into two stages, and the preparation time is about 2 - 4 h; finally, the rubber powder is blended with SAN resin to prepare the ASA resin.

[0009] CN113150460A prepares PBA latex by the one-step emulsion polymerization process (the acrylate monomer, emulsifier, diene monomer, and functional monomer are added into the reactor at one time, and the reaction is carried out for 2 h and then kept warm for 2 h to prepare PBA latex); then styrene and acrylonitrile are added for reaction for 2 - 6 h to prepare ASA graft latex; then the graft rubber powder is blended with SAN resin for processing to prepare ASA resin.

[0010] It can be seen that the current preparation of ASA graft latex mainly adopts the emulsion polymerization process of the seed method, that is, acrylate monomers, emulsifiers, initiators, electrolytes, etc. are first added, heated for reaction and aged and cooled to prepare ASA seed latex, and then acrylate monomers, emulsifiers, initiators, electrolytes, etc. are added to the seed latex, heated for reaction and aged and cooled to prepare ASA diameter-expanded latex, and finally graft monomers, emulsifiers, initiators, electrolytes, etc. are added to the diameter-expanded latex, heated for reaction and aged and cooled to prepare ASA graft latex. And to control the reaction heat release and improve the stability of the polymerization reaction, the monomers are often added to the system in a semi-continuous feeding method. The preparation process of the graft latex is complex, with many processes and low production efficiency. Especially in the industrial production process, each polymerization step requires a specific polymerization reactor, with more polymerization equipment used and higher equipment costs.

[0011] CN104231185B, CN109071737B, and CN113461864A all adopt the seed emulsion polymerization method to prepare ASA graft latex. The preparation process is complex, the reaction time required for each step is long, more polymerization equipment is required, and an active solution is introduced during the grafting process, resulting in more impurities in the system, which is not conducive to maintaining the appearance and performance of the resin.

[0012] Although CN101307121B concentrates the reaction processes of ASA seed latex, diameter-expanded latex, and graft latex in one reactor, reducing the usage of reactors during the reaction process, the feeding is carried out in batches during the polymerization process, the operation process is complex, and the polymerization reaction time for each step is long, and the improvement of the reaction efficiency is not obvious. In addition, batch feeding easily leads to a sharp rise in the reaction temperature and increases the difficulty of temperature control.

[0013] Although CN113150460A adopts a one-step emulsion polymerization process to prepare ASA diameter-expanded latex, the intermittent reaction releases heat violently and has high temperature control requirements. The prepared ASA diameter-expanded latex also needs to be cooled, and then the shell monomer is added and heated for reaction for 2 - 6 hours. The reaction time is long and more reaction kettles are required. In addition, the cross-linking agent uses butadiene, which has an adverse effect on the weather resistance of the ASA resin.

[0014] In summary, the field needs a preparation method for ASA core-shell graft copolymer latex with a simple preparation process, few processes, and high production efficiency. Summary of the Invention

[0015] Aiming at the problems existing in the prior art, the present invention provides a simplified preparation method for acrylate-styrene-acrylonitrile core-shell graft copolymer latex, which is prepared by concentrating the seed latex, diameter-expanded latex, and graft latex in one reaction system. There is no need to cool and discharge between polymerization steps, further improving the reaction efficiency; a nonionic-anionic amphoteric emulsifier with strong emulsifying ability is introduced into the system, which can ensure the stability of the polymerization system without increasing the amount of emulsifier, and avoid the deterioration of the resin performance caused by excessive emulsifier usage.

[0016] Specifically, one aspect of the present invention provides a method for preparing an acrylate-styrene-acrylonitrile core-shell graft copolymer latex, the method comprising the following steps:

[0017] (1) In a reaction system comprising an acrylate monomer, an emulsifier, a water-soluble initiator, and water, polymerize the acrylate monomer to prepare a seed latex;

[0018] (2) Drop a first-stage pre-emulsion into the seed latex for a diameter-expanding reaction to prepare a diameter-expanded latex, the first-stage pre-emulsion comprising an acrylate monomer, an emulsifier, a grafting agent, a crosslinking agent, a water-soluble initiator, and water;

[0019] (3) Drop a second-stage pre-emulsion into the diameter-expanded latex for a grafting reaction to prepare the acrylate-styrene-acrylonitrile core-shell graft copolymer latex, the second-stage pre-emulsion comprising a vinyl aromatic monomer, a vinyl nitrile monomer, an emulsifier, a water-soluble initiator, and water;

[0020] Wherein, the emulsifier in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion is a nonionic-anionic amphoteric emulsifier.

[0021] In one or more embodiments, the emulsifier in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion is independently selected from one or more of polyoxyethylene ether sulfonate emulsifiers and polyoxyethylene ether phosphate emulsifiers.

[0022] In one or more embodiments, the polyoxyethylene ether sulfonate emulsifier is sodium alkylphenol polyoxyethylene ether sulfosuccinate.

[0023] In one or more embodiments, the polyoxyethylene ether phosphate emulsifier is selected from one or more of sodium nonylphenol polyoxyethylene ether phosphate monoester and potassium alcohol ether phosphate monoester.

[0024] In one or more embodiments, the emulsifier in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion is independently selected from one or more of sodium nonylphenol polyoxyethylene ether phosphate monoester, sodium alkylphenol polyoxyethylene ether sulfosuccinate, and potassium alcohol ether phosphate monoester.

[0025] In one or more embodiments, the emulsifier in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion is sodium alkylphenol polyoxyethylene ether sulfosuccinate.

[0026] In one or more embodiments, the emulsifier in the reaction system of step (1), the first-stage pre-emulsion and the second-stage pre-emulsion is sodium nonylphenol polyoxyethylene ether phosphate monoester, and the sodium nonylphenol polyoxyethylene ether phosphate monoester has the structure shown in Formula I: n is the number of repeating units.

[0027] In one or more embodiments, in the reaction system of step (1), relative to 100 parts by mass of water, the amount of the acrylate monomer is 2-6 parts by mass, the amount of the emulsifier is 1-2 parts by mass, and the amount of the water-soluble initiator is 0.2-0.4 parts by mass.

[0028] In one or more embodiments, in step (1), the temperature of the polymerization reaction is 70-80 °C, and the time of the polymerization reaction is 0.5-1 h.

[0029] In one or more embodiments, in the first-stage pre-emulsion, relative to 50 parts by mass of water, the amount of the acrylate monomer is 54-58 parts by mass, the amount of the emulsifier is 1-2 parts by mass, the amount of the grafting agent is 0.2-1 part by mass, the amount of the crosslinking agent is 0.2-1 part by mass, and the amount of the water-soluble initiator is 0.2-0.4 parts by mass.

[0030] In one or more embodiments, in the reaction system of step (1), the mass ratio of the acrylate monomer to the acrylate monomer in the first-stage pre-emulsion is 2:58 to 6:54.

[0031] In one or more embodiments, in step (2), the first-stage pre-emulsion is added dropwise to the seed latex at 70-80 °C.

[0032] In one or more embodiments, in step (2), the first-stage pre-emulsion is added dropwise to the seed latex in 1.5-2 h to complete the diameter expansion reaction.

[0033] In one or more embodiments, in the second-stage pre-emulsion, relative to 50 parts by mass of water, the amount of the vinyl aromatic monomer is 25-35 parts by mass, the amount of the vinyl nitrile monomer is 5-15 parts by mass, the amount of the emulsifier is 1-2 parts by mass, and the amount of the water-soluble initiator is 0.2-0.4 parts by mass.

[0034] In one or more embodiments, the second-stage pre-emulsion includes a grafting agent.

[0035] In one or more embodiments, in the second-stage pre-emulsion, relative to 50 parts by mass of water, the amount of the grafting agent is 0.2-1 part by mass.

[0036] In one or more embodiments, the second-stage pre-emulsion comprises a crosslinking agent.

[0037] In one or more embodiments, in the second-stage pre-emulsion, based on 50 parts by mass of water, the amount of the crosslinking agent used is 0.2 - 1 part by mass.

[0038] In one or more embodiments, the total amount of the acrylate monomers in the reaction system of step (1) and the acrylate monomers in the first-stage pre-emulsion is counted as 60 parts by mass, and the total amount of the vinyl aromatic monomers and the vinyl nitrile monomers in the second-stage pre-emulsion is 30 - 50 parts by mass.

[0039] In one or more embodiments, in step (3), the second-stage pre-emulsion is added dropwise to the diameter-expanded latex at 70 - 80 °C.

[0040] In one or more embodiments, in step (3), the second-stage pre-emulsion is added dropwise to the diameter-expanded latex over 0.5 - 1 h.

[0041] In one or more embodiments, in step (3), after adding the second-stage pre-emulsion dropwise, the reaction is continued at 70 - 80 °C until the polymerization conversion rate > 98%.

[0042] In one or more embodiments, the prepared acrylate-styrene-acrylonitrile core-shell graft copolymer latex has a particle size of 240 - 340 nm.

[0043] In one or more embodiments, the acrylate monomers in the reaction system of step (1) and the acrylate monomers in the first-stage pre-emulsion are each independently one or more acrylic acid alkyl esters having the structural formula CH 2 =CHCOOR 1 where R 1 is a C1 - C15 alkyl group; preferably, the acrylate monomers in the reaction system of step (1) and the acrylate monomers in the first-stage pre-emulsion 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 monomers in the reaction system of step (1) and the acrylate monomers in the first-stage pre-emulsion are each independently one or more acrylic acid alkyl esters having the structural formula CH 2 =CHCOOR 2 where R 2 is a C1 - C4 linear alkyl group, more preferably butyl acrylate.

[0044] In one or more embodiments, the water-soluble initiator in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion is independently selected from one or more of sodium persulfate, potassium persulfate, ammonium persulfate, potassium persulfate, and hydrogen peroxide, and is preferably potassium persulfate.

[0045] In one or more embodiments, the grafting agent in the first-stage pre-emulsion is one or more compounds containing two or more different unsaturated vinyl functional groups, preferably selected from one or more of allyl methacrylate, triallyl isocyanurate, triallylamine, and diallylamine, and more preferably allyl methacrylate.

[0046] In one or more embodiments, the second-stage pre-emulsion contains a grafting agent, and the grafting agent in the second-stage pre-emulsion is one or more compounds containing two or more different unsaturated vinyl functional groups, preferably selected from one or more of allyl methacrylate, triallyl isocyanurate, triallylamine, and diallylamine, and more preferably allyl methacrylate.

[0047] In one or more embodiments, the crosslinking agent in the first-stage pre-emulsion is one or more compounds containing two or more identical unsaturated vinyl functional groups, preferably selected from one or more of ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, and 1,3-propanediol diacrylate, and more preferably ethylene glycol dimethacrylate.

[0048] In one or more embodiments, the second-stage pre-emulsion contains a crosslinking agent, and the crosslinking agent in the second-stage pre-emulsion is one or more compounds containing two or more identical unsaturated vinyl functional groups, preferably selected from one or more of ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, and 1,3-propanediol diacrylate, and more preferably ethylene glycol dimethacrylate.

[0049] In one or more embodiments, the vinyl aromatic monomer in the second-stage pre-emulsion is selected from one or more of styrene, α-methylstyrene, and p-methylstyrene, and is preferably styrene.

[0050] In one or more embodiments, the vinyl nitrile monomer in the second-stage pre-emulsion is selected from one or two of acrylonitrile and methacrylonitrile, and is preferably acrylonitrile.

[0051] Another aspect of the present invention provides an acrylate-styrene-acrylonitrile core-shell graft copolymer latex prepared by the method according to any one of the embodiments herein.

[0052] Another aspect of the present invention provides an acrylate-styrene-acrylonitrile core-shell graft copolymer, which is prepared from the acrylate-styrene-acrylonitrile core-shell graft copolymer latex described in any embodiment herein.

[0053] In one or more embodiments, the acrylate-styrene-acrylonitrile core-shell graft copolymer is prepared by demulsifying, heating and aging, washing, and drying the acrylate-styrene-acrylonitrile core-shell graft copolymer latex described in any embodiment herein; preferably, the temperature for heating and aging is 90-100 °C, and the time for heating and aging is 10-30 min.

[0054] Another aspect of the present invention provides an acrylate-styrene-acrylonitrile copolymer resin, which comprises the acrylate-styrene-acrylonitrile core-shell graft copolymer and acrylonitrile-styrene copolymer described in any embodiment herein.

[0055] In one or more embodiments, in the acrylate-styrene-acrylonitrile copolymer resin, the mass ratio of the acrylate-styrene-acrylonitrile core-shell graft copolymer to the acrylonitrile-styrene copolymer is 25:75 to 45:55.

[0056] In one or more embodiments, the acrylate-styrene-acrylonitrile copolymer resin is prepared by blending and extruding a material composition comprising the acrylate-styrene-acrylonitrile core-shell graft copolymer and the acrylonitrile-styrene copolymer.

[0057] In one or more embodiments, the material composition further comprises an antioxidant and / or a lubricant. Based on 100 parts by mass of the total mass of the 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.

[0058] In one or more embodiments, the temperature of the extrusion is 180-240 °C.

[0059] The present invention also provides the application of a nonionic anionic emulsifier in the preparation of a polymer latex.

[0060] In one or more embodiments, the nonionic-anionic amphoteric emulsifier is selected from one or more of polyoxyethylene ether sulfonate emulsifiers and polyoxyethylene ether phosphate emulsifiers; preferably, the polyoxyethylene ether sulfonate emulsifier is sodium alkylphenol polyoxyethylene ether sulfosuccinate, and the polyoxyethylene ether phosphate emulsifier is selected from one or more of sodium nonylphenol polyoxyethylene ether phosphate monoester and potassium alcohol ether phosphate monoester.

[0061] In one or more embodiments, the nonionic-anionic amphoteric emulsifier is sodium alkylphenol polyoxyethylene ether sulfosuccinate.

[0062] In one or more embodiments, the nonionic-anionic amphoteric emulsifier is sodium nonylphenol polyoxyethylene ether phosphate monoester, and the sodium nonylphenol polyoxyethylene ether phosphate monoester has the structure shown in Formula I: n is the number of repeating units.

[0063] In one or more embodiments, the polymer latex is acrylate-styrene-acrylonitrile copolymer latex, acrylonitrile-butadiene-styrene copolymer latex, styrene-butadiene rubber latex, chloroprene rubber latex, polyvinyl chloride latex, polybutadiene latex, polyacrylate latex or polyvinyl acetate latex. Detailed Description

[0064] 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 expressions 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 regarding the present invention. In case of conflict, the definition in this specification shall prevail.

[0065] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not in any way limit the scope of the present invention, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0066] As used herein, terms such as "comprising", "including", "containing" and similar terms encompass 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.

[0067] 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 brevity 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 numerical values within the ranges (including integers and fractions).

[0068] In this text, unless otherwise specified, percentages refer to mass percentages and ratios refer to mass ratios.

[0069] In this text, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all alternatives, improvements, and equivalents of the methods and materials described in the present invention can be covered within the scope defined by the claims.

[0070] In this text, for the sake of brevity of 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 to be within the scope described in this specification.

[0071] The present invention provides a simplified emulsion polymerization process for seed method, introducing special surfactants (nonionic-anionic amphoteric emulsifiers, such as sodium nonylphenol polyoxyethylene ether phosphate monoester, sodium alkylphenol polyoxyethylene ether sulfosuccinate, and / or potassium alcohol ether phosphate monoester). On the premise of ensuring the stability of the latex, multiple-step reactions are combined into one-step reaction, greatly shortening the polymerization reaction time, improving production efficiency, and simplifying the operation process. Using the method of the present invention to prepare ASA graft latex only requires one reactor, greatly reducing the equipment cost. The ASA graft latex polymerization formula of the present invention realizes reducing the use of auxiliaries on the premise of ensuring reaction stability and reaction rate, and does not use activation solution, reducing production operation and cost. The reduction of the dosage of auxiliaries is also beneficial to reducing the treatment cost of production sewage, optimizing the appearance of processed resin, and improving the weather resistance of the resin.

[0072] The method for preparing acrylate-styrene-acrylonitrile core-shell graft copolymer latex (abbreviated as ASA latex) of the present invention includes the following steps:

[0073] (1) In a reaction system containing acrylate monomers, emulsifiers, water-soluble initiators, and water, the acrylate monomers are polymerized to prepare seed latex.

[0074] (2) A first-stage pre-emulsion is added dropwise to the seed latex for a diameter-expanding reaction to prepare diameter-expanded latex. The first-stage pre-emulsion contains acrylate monomers, emulsifiers, grafting agents, crosslinking agents, water-soluble initiators, and water.

[0075] (3) A second-stage pre-emulsion is added dropwise to the diameter-expanded latex for a grafting reaction to prepare ASA latex. The second-stage pre-emulsion contains vinyl aromatic monomers, vinyl nitrile monomers, emulsifiers, water-soluble initiators, and water.

[0076] The present invention uses a nonionic-anionic amphoteric emulsifier as the emulsifier in the latex reaction system. Available nonionic-anionic amphoteric emulsifiers include polyoxyethylene ether sulfonate salts and polyoxyethylene ether phosphate salts.

[0077] Examples of polyoxyethylene ether sulfonate salts include sodium alkylphenol polyoxyethylene ether sulfosuccinate (i.e., emulsifier MS-1). Examples of polyoxyethylene ether phosphate salts include potassium alcohol ether phosphate monoester and sodium nonylphenol polyoxyethylene ether phosphate monoester. Available potassium alcohol ether phosphate monoester includes potassium lauryl alcohol ether phosphate (i.e., MAP-K). The nonionic-anionic amphoteric emulsifiers applicable to the present invention (such as sodium nonylphenol polyoxyethylene ether phosphate monoester, sodium alkylphenol polyoxyethylene ether sulfosuccinate, and potassium alcohol ether phosphate monoester) can all be purchased through commercial channels.

[0078] Preferably, in the preparation process of the ASA latex of the present invention, no other emulsifiers are used except for nonionic-anionic amphoteric emulsifiers.

[0079] The emulsifiers in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion can be the same or different.

[0080] In some preferred embodiments, the emulsifiers in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion are each independently selected from one or more of sodium nonylphenol polyoxyethylene ether phosphate monoester, sodium alkylphenol polyoxyethylene ether sulfosuccinate, and potassium alcohol ether phosphate monoester. For example, they can each independently be selected from one or two of sodium nonylphenol polyoxyethylene ether phosphate monoester and sodium alkylphenol polyoxyethylene ether sulfosuccinate.

[0081] In some preferred embodiments, the emulsifiers in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion are all sodium alkylphenol polyoxyethylene ether sulfosuccinate.

[0082] In some preferred embodiments, the emulsifiers in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion are all sodium nonylphenol polyoxyethylene ether phosphate monoester. Sodium nonylphenol polyoxyethylene ether phosphate monoester has the structure shown in Formula I: n is the number of repeating units. The molecular weight of sodium nonylphenol polyoxyethylene ether phosphate monoester applicable to the present invention can be 400 - 1000, such as 500, 600, 700, 800, 900. The emulsifiers applicable to the present invention can be purchased through commercial channels.

[0083] In the present invention, water is preferably deionized water.

[0084] In the reaction system of step (1), relative to 100 parts by mass of water, the amount of acrylate monomer used can be 2 - 6 parts by mass, such as 3 parts by mass, 4 parts by mass, 5 parts by mass.

[0085] In the reaction system of step (1), relative to 100 parts by mass of water, the amount of the emulsifier is preferably 1 - 2 parts by mass, such as 1.2 parts by mass, 1.5 parts by mass, 1.8 parts by mass. When the amount of the emulsifier is too low, the stability of the prepared latex is poor and more precipitation occurs; when the amount of the emulsifier is too high, although the polymerization stability is good, demulsification is difficult, and the appearance of the final processed resin is also poor, and the weather resistance is also poor.

[0086] In the reaction system of step (1), relative to 100 parts by mass of water, the amount of the water-soluble initiator can be 0.2 - 0.4 parts by mass, such as 0.25 parts by mass, 0.3 parts by mass, 0.35 parts by mass.

[0087] In some embodiments, the reaction system of step (1) further contains other monomers in addition to the acrylate monomer.

[0088] In some embodiments, the reaction system of step (1) further contains other additives in addition to the emulsifier and the water-soluble initiator.

[0089] In some embodiments, no other substances are added to the reaction system of step (1) except for the acrylate monomer, the emulsifier, the water-soluble initiator, water, and other possible monomers.

[0090] In some embodiments, the reaction system of step (1) consists of an acrylate monomer, an emulsifier, a water-soluble initiator, and water.

[0091] In step (1), the temperature of the polymerization reaction is preferably 70 - 80 °C, such as 72 °C, 75 °C, 78 °C.

[0092] In step (1), the time of the polymerization reaction is preferably 0.5 - 1 h, such as 0.6 h, 0.7 h, 0.8 h, 0.9 h.

[0093] In step (1), before the polymerization reaction, the components of the reaction system can be first mixed evenly. For example, after mixing the components of the reaction system first, stir for 5 - 15 min (such as 10 min) to obtain a uniform emulsion, and then raise the temperature to the reaction temperature for the polymerization reaction.

[0094] In step (2), the first-stage pre-emulsion is an emulsion formed by mixing its components evenly. Conventional methods (such as stirring) can be used to mix the components of the first-stage pre-emulsion evenly.

[0095] In some embodiments, the first-stage pre-emulsion further contains other monomers in addition to the acrylate monomer.

[0096] In some embodiments, the first-stage pre-emulsion further contains other additives in addition to the emulsifier and the water-soluble initiator.

[0097] In some embodiments, a first-stage pre-emulsion does not contain substances other than acrylate monomers, emulsifiers, grafting agents, cross-linking agents, water-soluble initiators, water, and other monomers that may be present.

[0098] In some embodiments, a first-stage pre-emulsion consists of acrylate monomers, emulsifiers, grafting agents, cross-linking agents, water-soluble initiators, and water.

[0099] In the first-stage pre-emulsion, with respect to 50 parts by mass of water, the amount of acrylate monomers used can be 54 - 58 parts by mass, such as 55 parts by mass, 56 parts by mass, 57 parts by mass.

[0100] In the first-stage pre-emulsion, with respect to 50 parts by mass of water, the amount of emulsifier used is preferably 1 - 2 parts by mass, such as 1.2 parts by mass, 1.5 parts by mass, 1.8 parts by mass. When the amount of emulsifier used is too low, the stability of the prepared latex is poor and more precipitation occurs; when the amount of emulsifier used is too high, although the polymerization stability is good, demulsification is difficult, and the appearance of the final processed resin is also poor, and the weather resistance is also poor.

[0101] In the first-stage pre-emulsion, with respect to 50 parts by mass of water, the amount of grafting agent used can be 0.2 - 1 part by mass, such as 0.3 part by mass, 0.5 part by mass, 0.7 part by mass.

[0102] In the first-stage pre-emulsion, with respect to 50 parts by mass of water, the amount of cross-linking agent used can be 0.2 - 1 part by mass, such as 0.3 part by mass, 0.5 part by mass, 0.7 part by mass.

[0103] In the first-stage pre-emulsion, with respect to 50 parts by mass of water, the amount of water-soluble initiator used can be 0.2 - 0.4 part by mass, such as 0.25 part by mass, 0.3 part by mass, 0.35 part by mass.

[0104] In the reaction system of step (1), the mass ratio of acrylate monomers to the acrylate monomers in the first-stage pre-emulsion is preferably 2:58 to 6:54, such as 3:75, 4:56, 5:55.

[0105] In step (2), it is preferred to add the first-stage pre-emulsion dropwise to the seed latex at 70 - 80 °C (such as 75 °C). A peristaltic pump can be used for the dropwise addition. The dropwise addition time can be 1.5 - 2 h, such as 1.6 h, 1.7 h, 1.8 h, 1.9 h. After the dropwise addition of the first-stage pre-emulsion is completed, the second-stage pre-emulsion can be added dropwise.

[0106] In step (3), the second-stage pre-emulsion is an emulsion formed by mixing its components uniformly. Conventional methods (such as stirring) can be used to mix the components of the second-stage pre-emulsion uniformly.

[0107] The second-stage pre-emulsion may optionally contain one or both selected from grafting agents and crosslinking agents.

[0108] In some embodiments, the second-stage pre-emulsion contains a grafting agent and a crosslinking agent.

[0109] In some embodiments, the second-stage pre-emulsion further contains other monomers besides vinyl aromatic monomers and vinyl nitrile monomers.

[0110] In some embodiments, the first-stage pre-emulsion further contains other additives besides emulsifiers and water-soluble initiators.

[0111] In some embodiments, the second-stage pre-emulsion does not contain other substances besides vinyl aromatic monomers, vinyl nitrile monomers, emulsifiers, optional grafting agents, optional crosslinking agents, water-soluble initiators, water, and other possible monomers.

[0112] In some embodiments, the second-stage pre-emulsion consists of vinyl aromatic monomers, vinyl nitrile monomers, emulsifiers, grafting agents, crosslinking agents, water-soluble initiators, and water.

[0113] In the second-stage pre-emulsion, relative to 50 parts by mass of water, the amount of vinyl aromatic monomers used can be 25 - 35 parts by mass, such as 27 parts by mass, 30 parts by mass, 33 parts by mass.

[0114] In the second-stage pre-emulsion, relative to 50 parts by mass of water, the amount of vinyl nitrile monomers used can be 5 - 15 parts by mass, such as 7 parts by mass, 10 parts by mass, 13 parts by mass.

[0115] In the present invention, relative to the total of 60 parts by mass of acrylate monomers in the reaction system of step (1) and acrylate monomers in the first-stage pre-emulsion, the sum of the amounts of vinyl aromatic monomers and vinyl nitrile monomers used in the second-stage pre-emulsion is preferably 30 - 50 parts by mass, such as 35 parts by mass, 40 parts by mass, 45 parts by mass.

[0116] In the second-stage pre-emulsion, relative to 50 parts by mass of water, the amount of emulsifier used is preferably 1 - 2 parts by mass, such as 1.2 parts by mass, 1.5 parts by mass, 1.8 parts by mass. When the amount of emulsifier used is too low, the stability of the prepared latex is poor and precipitation is excessive; when the amount of emulsifier used is too high, although the polymerization stability is good, demulsification is difficult, and the appearance of the final processed resin is also not good, and the weather resistance is also poor.

[0117] When the second-stage pre-emulsion contains a grafting agent, in the second-stage pre-emulsion, relative to 50 parts by mass of water, the amount of grafting agent used can be 0.2 - 1 part by mass, such as 0.3 part by mass, 0.5 part by mass, 0.7 part by mass.

[0118] When the second-stage pre-emulsion contains a crosslinking agent, in the second-stage pre-emulsion, based on 50 parts by mass of water, the amount of the crosslinking agent can be 0.2-1 part by mass, such as 0.3 part by mass, 0.5 part by mass, 0.7 part by mass.

[0119] In the second-stage pre-emulsion, based on 50 parts by mass of water, the amount of the water-soluble initiator can be 0.2-0.4 part by mass, such as 0.25 part by mass, 0.3 part by mass, 0.35 part by mass.

[0120] In step (3), it is preferred to add the second-stage pre-emulsion dropwise to the diameter-expanded latex at 70-80 °C (such as 75 °C). A peristaltic pump can be used for the dropwise addition. The dropwise addition time can be 0.5-1 h, such as 0.6 h, 0.7 h, 0.8 h, 0.9 h. After the dropwise addition of the second-stage pre-emulsion is completed, it is preferred to continue the reaction at 70-80 °C (such as 75 °C) until the polymerization conversion rate > 98%. For example, after the dropwise addition of the second-stage pre-emulsion is completed, the reaction can be continued at 70-80 °C (such as 75 °C) for 0.5-1.5 h, such as 0.8 h, 1 h, 1.2 h. After the reaction is completed, the temperature can be lowered to room temperature to stop the reaction.

[0121] In the present invention, the particle size of the prepared ASA latex is preferably 240-340 nm, such as 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm. The acrylate-styrene-acrylonitrile core-shell graft copolymer latex with a particle size within the foregoing range has better stability, and the processed ASA resin has better strength, appearance and weather resistance.

[0122] In the present invention, the acrylate monomers in the reaction system of step (1) and the first-stage pre-emulsion can be the same or different. The acrylate monomers applicable to the present invention can be one or more acrylate alkyl esters with the structural formula CH 2 =CHCOOR 1 where R 1 is a C1-C15 alkyl group, such as a C1-C15 linear alkyl group. In some embodiments, R 1 is a C1-C12 alkyl group, such as a C1-C12 linear alkyl group. In some embodiments, R 1 is a C1-C8 alkyl group, such as a C1-C8 linear alkyl group. In some preferred embodiments, R 1 is a C1-C4 alkyl group, such as a C1-C4 linear alkyl group.

[0123] In some embodiments, the acrylate monomers applicable to the present invention are 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. In some preferred embodiments, the acrylate monomer in the reaction system of step (1) and the first-stage pre-emulsion is butyl acrylate, such as n-butyl acrylate.

[0124] In the present invention, the water-soluble initiators in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion may be the same or different. Usable water-soluble initiators include, but are not limited to, one or more selected from sodium persulfate, potassium persulfate, ammonium persulfate, potassium peroxophosphate, and hydrogen peroxide. In some preferred embodiments, the water-soluble initiator in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion is potassium persulfate.

[0125] In the present invention, the grafting agents in the first-stage pre-emulsion and the second-stage pre-emulsion may be the same or different. In the present invention, the grafting agent is one or more compounds containing two or more different unsaturated vinyl functional groups. In some embodiments, the grafting agent is selected from one or more of allyl methacrylate, triallyl isocyanurate, triallylamine, and diallylamine, preferably allyl methacrylate.

[0126] In the present invention, the crosslinking agents in the first-stage pre-emulsion and the second-stage pre-emulsion may be the same or different. In the present invention, the crosslinking agent is one or more compounds containing two or more identical unsaturated vinyl functional groups. In some embodiments, 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 ethylene glycol dimethacrylate.

[0127] In the present invention, the vinyl aromatic monomer is a compound containing a vinyl group and an aromatic ring. In some embodiments, the vinyl aromatic monomer in the second-stage pre-emulsion is selected from one or more of styrene, α-methylstyrene, and p-methylstyrene, preferably styrene.

[0128] In the present invention, the vinyl nitrile monomer is a compound containing a vinyl group and a nitrile group. In some embodiments, the vinyl nitrile monomer in the second-stage pre-emulsion is selected from one or two of acrylonitrile and methacrylonitrile, preferably acrylonitrile.

[0129] In the present invention, acrylate-styrene-acrylonitrile core-shell graft copolymer (hereinafter referred to as ASA) can be prepared by demulsifying ASA latex, heating it for aging at an elevated temperature, washing, and drying. The powdery ASA is called ASA rubber powder. The demulsification method can be conventional. For example, the ASA latex can be diluted first, and then an inorganic salt aqueous solution, such as magnesium sulfate aqueous solution, can be added at 70-90 °C (such as 80 °C) for demulsification. The temperature for heating and aging can be 90-100 °C, such as 95 °C. The time for heating and aging can be 10-30 min, such as 15 min, 20 min, 25 min. In some embodiments, an aqueous salt solution is added to the ASA latex at 70-90 °C (such as 80 °C) for demulsification, heated to 90-100 °C (such as 95 °C) for aging, washed, centrifuged for dehydration, and dried to obtain ASA rubber powder.

[0130] In the present invention, after mixing ASA (such as ASA rubber powder) with acrylonitrile-styrene copolymer (SAN resin), additives are optionally or preferably added for blending, and acrylate-styrene-acrylonitrile copolymer resin (hereinafter referred to as ASA resin) can be prepared by extrusion. In the ASA resin, the mass ratio of ASA to SAN resin can be 25:75 to 45:55, such as 30:70, 35:65, 40:60. The additives can be antioxidants and / or lubricants. Based on 100 parts by mass of the total mass of ASA and SAN resin, the mass of the antioxidant can be 0.2-0.5 parts by mass, and the mass of the lubricant can be 0.2-0.5 parts by mass. The extrusion can be carried out at 180-240 °C. A twin-screw extruder can be used for extrusion. Granulation can be carried out after extrusion.

[0131] The present invention also provides the use of nonionic-anionic amphoteric emulsifiers in the preparation of polymers (such as ASA, ABS, styrene-butadiene rubber, chloroprene rubber, polyvinyl chloride, polybutadiene, polyacrylate, polyvinyl acetate, etc.) or their latexes. The nonionic-anionic amphoteric emulsifier is used as an efficient emulsifier in the preparation of polymers or their latexes, better dispersing the reaction monomers and polymers in water, which is beneficial to heat dissipation during the polymerization process and controlling the particle size of the polymers.

[0132] The present invention has achieved the following beneficial technical effects:

[0133] 1. The biggest innovation of the present invention is to combine multiple batches of reactions for preparing general ASA graft latex into one reaction, greatly shortening the reaction time, without affecting the latex stability and the performance of the final product, improving the production efficiency, reducing the usage of polymerization reactors, and lowering the production cost.

[0134] 2. The present invention introduces an amphoteric special emulsifier with anionic and nonionic properties (such as sodium nonylphenol polyoxyethylene ether phosphate monoester, sodium alkylphenol polyoxyethylene ether sulfosuccinate, and / or potassium alcohol ether phosphate monoester). Without increasing the dosage of the emulsifier, it greatly ensures the stability of the polymerization reaction system, reduces the precipitation during the reaction, lowers the production cost, and guarantees the mechanical properties and weather resistance of the resin.

[0135] 3. The types and dosages of the polymerization process aids used in the present invention are very small, and an activation solution (used in combination with an oil-soluble initiator) is not used, reducing production operations and costs. The reduction in the dosage of the aids is also beneficial to reducing the treatment cost of production sewage, optimizing the appearance of the processed resin, and improving the weather resistance of the resin.

[0136] 4. The general polymerization process for preparing ASA graft latex has many steps, generally carried out in multiple batches, using multiple polymerization reactors, with a long time for each step, a cumbersome process, and specific latex storage tanks required for each step of the product, resulting in a high equipment cost. The present invention adopts a simplified seed emulsion polymerization process, combining multiple-step reactions into one-step reactions, greatly shortening the polymerization reaction time, improving production efficiency, and only requiring one reactor, greatly reducing the experimental cost.

[0137] The present invention will be described below by way of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents, and materials used in the examples and comparative examples are conventional methods, reagents, and materials in the art unless otherwise specified. The raw material compounds in the examples and comparative examples can be obtained through commercial channels. The feeding parts in the examples and comparative examples are all in parts by mass.

[0138] The sodium nonylphenol polyoxyethylene ether phosphate monoester used in the examples and comparative examples was purchased from Nantong Hengrun Chemical Co., Ltd., with the model TXP-10.

[0139] The sodium alkylphenol polyoxyethylene ether sulfosuccinate used in the examples was purchased from Jingzhou Longhua Petrochemical Co., Ltd., with the model Nongru-2000.

[0140] The test methods involved in the examples and comparative examples are as follows:

[0141] (1) Particle size: Measured by a Litesizer particle size analyzer from Anton Paar. If not specified, it is defaulted to the number average particle size.

[0142] (2) 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). Calculate the polymerization conversion rate using the following equation.

[0143] Aggregate conversion rate (%) = [(Total polymer solid content - Solid content of added auxiliary materials) / (Theoretical total solid content of the system - Solid content of added auxiliary materials)] * 100

[0144] (3) Gel separation rate: Cut and dry a filter screen (120 mesh), weigh its mass, denoted as m1, then cover it on the sample bottle mouth. Transfer the latex in the reactor to the sample bottle through the filter screen, transfer the gel separated on the inner wall of the reactor and the stirring paddle to the filter screen. After that, rinse the filter screen with water until the liquid is clear, then transfer it to a blast drying oven and dry it at 80 °C to constant weight, and weigh its mass, denoted as m2.

[0145] Gel separation rate = (m2 - m1) / Total mass of the formulated feedstock

[0146] (4) Weather resistance: According to the standard method SAE J 2527, use xenon lamp irradiation for aging test, and the irradiation energy is 2500 KJ / m 2 . Test the CIE Lab values before and after the experiment through a colorimeter of X-Rite company, and calculate △E. The smaller △E is, the better the weather resistance.

[0147] (5) Impact strength: Test according to the standard of GB / T 1843-2008 "Determination of Izod impact strength", and express it in units of kilojoules per square meter (kJ / m 2 ).

[0148] Example 1

[0149] I. Preparation of ASA grafted latex

[0150] After replacing the reaction kettle with nitrogen and maintaining nitrogen sealing, add 6 parts of n-butyl acrylate, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.3 parts of potassium persulfate and 100 parts of deionized water. Stir and dissolve for 10 min, then heat up to 70 °C and react for 0.5 h. Keep the reactor at a constant temperature of 70 °C, and use a peristaltic pump to dropwise add the first-stage pre-emulsion into the reactor within 1.5 h to prepare ASA diameter-expanded latex. After the addition of the first-stage pre-emulsion is completed, keep the reactor at a constant temperature of 70 °C, and use a peristaltic pump to dropwise add the second-stage pre-emulsion into the reactor within 1 h. After the addition of the second-stage pre-emulsion is completed, continue to react at 70 °C for 1 h. The aggregate conversion rate is greater than 98%, then cool down to room temperature to stop the reaction, and prepare an ASA grafted latex with a particle size of 252 nm.

[0151] The first-stage pre-emulsion includes 54 parts of n-butyl acrylate, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 parts of allyl methacrylate, 0.5 parts of ethylene glycol dimethacrylate, 0.3 parts of potassium persulfate and 50 parts of deionized water.

[0152] The two-stage pre-emulsion comprises 30 parts of styrene, 10 parts of acrylonitrile, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0153] II. Preparation of ASA grafted rubber powder

[0154] The prepared ASA grafted latex is diluted (100 parts of latex, 100 parts of deionized water), heated to 80 °C in a reactor, then an aqueous solution of magnesium sulfate (40 parts, concentration 5 wt%) is added for demulsification, the temperature is raised to 95 °C for curing for 30 min, washing, centrifugal dehydration and drying to obtain ASA grafted rubber powder.

[0155] III. Preparation of ASA resin

[0156] Take 30 parts of the ASA grafted rubber powder prepared in step II (based on the weight of 100 parts of ASA resin), 70 parts of Taichung NF2200 SAN resin (based on the weight of 100 parts of ASA resin), 0.2 part of antioxidant 1010 (based on the weight of 100 parts of ASA resin) and 0.4 part of lubricant ethylene bisstearamide (based on the weight of 100 parts of ASA resin) for blending, and then granulate with a twin-screw extruder at 180 - 240 °C to obtain ASA resin particles. After drying, test specimens are prepared by an injection molding machine.

[0157] Example 2

[0158] I. Preparation of ASA grafted latex

[0159] After replacing the reactor with nitrogen and maintaining nitrogen sealing, 2 parts of n-butyl acrylate, 1.5 parts of alkylphenol polyoxyethylene ether sulfosuccinate sodium salt, 0.3 part of potassium persulfate and 100 parts of deionized water are added, stirred and dissolved for 10 min, then the temperature is raised to 70 °C and reacted for 0.5 h. Keep the reactor at a constant temperature of 70 °C, and use a peristaltic pump to drop the first-stage pre-emulsion into the reactor within 1.5 h to prepare ASA diameter-expanded latex. After the dropping of the first-stage pre-emulsion is completed, keep the reactor at a constant temperature of 70 °C, and use a peristaltic pump to drop the second-stage pre-emulsion into the reactor within 1 h. After the dropping of the second-stage pre-emulsion is completed, continue to react at a constant temperature of 70 °C for 1 h, the polymerization conversion rate is greater than 98%, and the reaction is stopped by cooling to room temperature to prepare ASA grafted latex with a particle size of 335 nm.

[0160] The first-stage pre-emulsion comprises 58 parts of n-butyl acrylate, 1.5 parts of alkylphenol polyoxyethylene ether sulfosuccinate sodium salt, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0161] The two-stage pre-emulsion comprises 30 parts of styrene, 10 parts of acrylonitrile, 1.5 parts of sodium alkylphenol polyoxyethylene ether sulfosuccinate, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0162] The remaining steps are the same as those in Example 1.

[0163] Example 3

[0164] I. Preparation of ASA grafted latex

[0165] After purging the reactor with nitrogen and maintaining nitrogen sealing, add 4 parts of n-butyl acrylate, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.3 part of potassium persulfate and 100 parts of deionized water. Stir and dissolve for 10 min, then heat up to 70 °C and react for 0.5 h. Keep the reactor at a constant temperature of 70 °C, and use a peristaltic pump to dropwise add the first-stage pre-emulsion into the reactor within 1.5 h to prepare the ASA diameter-expanded latex. After the dropwise addition of the first-stage pre-emulsion is completed, keep the reactor at a constant temperature of 70 °C, and use a peristaltic pump to dropwise add the second-stage pre-emulsion into the reactor within 1 h. After the dropwise addition of the second-stage pre-emulsion is completed, continue to react at 70 °C for 1 h. The polymerization conversion rate is greater than 98%. Cool down to room temperature to stop the reaction, and prepare the ASA grafted latex with a particle size of 289 nm.

[0166] The first-stage pre-emulsion comprises 56 parts of n-butyl acrylate, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0167] The second-stage pre-emulsion comprises 30 parts of styrene, 10 parts of acrylonitrile, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0168] The remaining steps are the same as those in Example 1.

[0169] Example 4

[0170] I. Preparation of ASA grafted latex

[0171] After replacing the reactor with nitrogen and maintaining nitrogen sealing, add 6 parts of n-butyl acrylate, 1 part of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.3 part of potassium persulfate and 100 parts of deionized water. Stir and dissolve for 10 min, then heat up to 70 °C and react for 0.5 h. Keep the reactor at a constant temperature of 70 °C, and use a peristaltic pump to dropwise add a first-stage pre-emulsion into the reactor within 1.5 h to prepare an ASA diameter-expanded latex. After the addition of the first-stage pre-emulsion is completed, keep the reactor at a constant temperature of 70 °C, and use a peristaltic pump to dropwise add a second-stage pre-emulsion into the reactor within 1 h. After the addition of the second-stage pre-emulsion is completed, continue to react at a constant temperature of 70 °C for 1 h. The polymerization conversion rate is greater than 98%. Cool down to room temperature to stop the reaction, and prepare an ASA grafted latex with a particle size of 260 nm.

[0172] The first-stage pre-emulsion includes 54 parts of n-butyl acrylate, 1 part of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0173] The second-stage pre-emulsion includes 30 parts of styrene, 10 parts of acrylonitrile, 1 part of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0174] The remaining steps are the same as those in Example 1.

[0175] Example 5

[0176] I. Preparation of ASA grafted latex

[0177] After replacing the reactor with nitrogen and maintaining nitrogen sealing, add 6 parts of n-butyl acrylate, 2 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.3 part of potassium persulfate and 100 parts of deionized water. Stir and dissolve for 10 min, then heat up to 70 °C and react for 0.5 h. Keep the reactor at a constant temperature of 70 °C, and use a peristaltic pump to dropwise add a first-stage pre-emulsion into the reactor within 1.5 h to prepare an ASA diameter-expanded latex. After the addition of the first-stage pre-emulsion is completed, keep the reactor at a constant temperature of 70 °C, and use a peristaltic pump to dropwise add a second-stage pre-emulsion into the reactor within 1 h. After the addition of the second-stage pre-emulsion is completed, continue to react at a constant temperature of 70 °C for 1 h. The polymerization conversion rate is greater than 98%. Cool down to room temperature to stop the reaction, and prepare an ASA grafted latex with a particle size of 245 nm.

[0178] The first-stage pre-emulsion includes 54 parts of n-butyl acrylate, 2 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0179] The two-stage pre-emulsion comprises 30 parts of styrene, 10 parts of acrylonitrile, 2 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0180] The remaining steps are the same as those in Example 1.

[0181] Example 6

[0182] I. Preparation of ASA grafted latex

[0183] After replacing the reactor with nitrogen and maintaining nitrogen sealing, 6 parts of n-butyl acrylate, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.3 part of potassium persulfate and 150 parts of deionized water are added. After stirring and dissolving for 10 min, the temperature is raised to 70 °C and reacted for 0.5 h. Keeping the reactor at a constant temperature of 70 °C, the first-stage pre-emulsion is added dropwise to the reactor with a peristaltic pump within 1.5 h to prepare the ASA diameter-expanded latex. After the addition of the first-stage pre-emulsion is completed, keep the reactor at a constant temperature of 70 °C, and add the second-stage pre-emulsion to the reactor with a peristaltic pump within 1 h. After the addition of the second-stage pre-emulsion is completed, continue to react at 70 °C for 1 h. The polymerization conversion rate is greater than 98%. The reaction is stopped by cooling to room temperature, and the ASA grafted latex with a particle size of 255 nm is prepared.

[0184] The first-stage pre-emulsion comprises 54 parts of n-butyl acrylate, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0185] The second-stage pre-emulsion comprises 30 parts of styrene, 10 parts of acrylonitrile, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0186] The remaining steps are the same as those in Example 1.

[0187] Comparative Example 1

[0188] I. Preparation of ASA grafted latex

[0189] After replacing the reactor with nitrogen and maintaining nitrogen sealing, 6 parts of n-butyl acrylate, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.3 parts of potassium persulfate, 0.3 parts of sodium bicarbonate, 0.15 parts of sodium pyrophosphate and 100 parts of deionized water were added. After stirring and dissolving for 10 min, the temperature was raised to 70 °C and reacted for 0.5 h. The reactor was maintained at a constant temperature of 70 °C, and a first-stage pre-emulsion was added dropwise to the reactor with a peristaltic pump within 1.5 h to prepare an ASA diameter-expanded latex. After the addition of the first-stage pre-emulsion was completed, the reactor was maintained at a constant temperature of 70 °C, and a second-stage pre-emulsion was added dropwise to the reactor with a peristaltic pump within 1 h. After the addition of the second-stage pre-emulsion was completed, the reaction continued at a constant temperature of 70 °C for 1 h, the polymerization conversion rate was greater than 98%, and the reaction was stopped after cooling to room temperature to obtain an ASA grafted latex with a particle size of 256 nm.

[0190] The first-stage pre-emulsion includes 54 parts of n-butyl acrylate, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 parts of allyl methacrylate, 0.5 parts of ethylene glycol dimethacrylate, 0.3 parts of potassium persulfate and 50 parts of deionized water.

[0191] The second-stage pre-emulsion includes 30 parts of styrene, 10 parts of acrylonitrile, 1.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 parts of allyl methacrylate, 0.5 parts of ethylene glycol dimethacrylate, 0.3 parts of potassium persulfate and 50 parts of deionized water.

[0192] The remaining steps are the same as those in Example 1.

[0193] Comparative Example 2

[0194] I. Preparation of ASA grafted latex

[0195] 1. Preparation of small particle size acrylate seeds

[0196] After replacing the reactor with nitrogen, 20 parts of n-butyl acrylate, 150 parts of deionized water, 3 parts of sodium dodecyl sulfate, 0.35 parts of sodium bicarbonate and 0.25 parts of potassium persulfate were added. The temperature was raised to 70 °C and reacted for 30 min. Then, 80 parts of n-butyl acrylate were added to the reactor with a peristaltic pump within 4 h. After addition, the reaction was carried out at a constant temperature for 2 h, and the polymerization conversion rate reached 98%. The reaction was stopped after cooling to room temperature to obtain a small particle size acrylate seed latex.

[0197] 2. Preparation of large particle size acrylate latex

[0198] After the reaction kettle is purged with nitrogen, 6 parts (by dry basis mass) of the seed latex prepared in Step 1, 20 parts of n-butyl acrylate, 0.1 part of ethylene glycol dimethacrylate, 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 are charged, and the temperature is raised to 70 °C and reacted for 30 min. Then, the pre-emulsion is added to the reaction kettle within 4 h using a peristaltic pump. After the addition is complete, the reaction is carried out at a constant temperature for 2 h. When the polymerization conversion rate reaches 98%, the temperature is lowered to room temperature to stop the reaction, and a large-particle-size acrylate latex is prepared. The pre-emulsion includes 80 parts of n-butyl acrylate, 0.4 part of ethylene glycol dimethacrylate, 0.2 part of potassium persulfate, 2 parts of sodium dodecyl sulfate, and 50 parts of deionized water.

[0199] 3. Preparation of ASA grafted latex

[0200] After the reaction kettle is purged with nitrogen, 60 parts (by dry basis mass) of the large-particle-size polyacrylate latex prepared in Step 2, 120 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 are charged, and the temperature is raised to 70 °C and reacted for 30 min. While maintaining the reaction temperature, the pre-emulsion is added to the reaction kettle within 4 h using a peristaltic pump. After the addition, the reaction is carried out at a constant temperature for 2 h. When the polymerization conversion rate reaches 98%, the temperature is lowered to room temperature to stop the reaction, and an ASA graft copolymer latex is prepared. The pre-emulsion includes 24 parts of styrene, 8 parts of acrylonitrile, 0.2 part of cumene hydroperoxide, 2 parts of sodium dodecyl sulfate, and 30 parts of deionized water.

[0201] The remaining steps are the same as in Example 1.

[0202] Comparative Example 3

[0203] I. Preparation of ASA grafted latex

[0204] The reaction kettle is purged with nitrogen and then kept under nitrogen seal. 6 parts of n-butyl acrylate, 0.5 part of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.3 part of potassium persulfate, and 100 parts of deionized water are added. After stirring and dissolving for 10 min, the temperature is raised to 70 °C and reacted for 0.5 h. While maintaining the reactor at a constant temperature of 70 °C, the first-stage pre-emulsion is added dropwise to the reactor within 1.5 h using a peristaltic pump to prepare an ASA diameter-expanded latex. After the addition of the first-stage pre-emulsion is completed, the reactor is kept at a constant temperature of 70 °C, and the second-stage pre-emulsion is added dropwise to the reactor within 1 h using a peristaltic pump. After the addition of the second-stage pre-emulsion is completed, the reaction is continued at 70 °C for 1 h. When the polymerization conversion rate is greater than 98%, the temperature is lowered to room temperature to stop the reaction, and an ASA grafted latex with a particle size of 241 nm is prepared.

[0205] A pre-emulsion consists of 54 parts of n-butyl acrylate, 0.5 part of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0206] The second-stage pre-emulsion consists of 30 parts of styrene, 10 parts of acrylonitrile, 0.5 part of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0207] The remaining steps are the same as those in Example 1.

[0208] Comparative Example 4

[0209] I. Preparation of ASA graft latex

[0210] After purging the reactor with nitrogen and maintaining nitrogen sealing, 6 parts of n-butyl acrylate, 2.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.3 part of potassium persulfate and 100 parts of deionized water are added. After stirring and dissolving for 10 min, the temperature is raised to 70 °C and reacted for 0.5 h. Keeping the reactor at a constant temperature of 70 °C, the first-stage pre-emulsion is added dropwise to the reactor with a peristaltic pump over 1.5 h to prepare an ASA diameter-expanded latex. After the addition of the first-stage pre-emulsion is completed, the reactor is kept at a constant temperature of 70 °C, and the second-stage pre-emulsion is added dropwise to the reactor with a peristaltic pump over 1 h. After the addition of the second-stage pre-emulsion is completed, the reaction is continued at a constant temperature of 70 °C for 1 h. The polymerization conversion rate is greater than 98%. The reaction is stopped by cooling to room temperature, and an ASA graft latex with a particle size of 255 nm is prepared.

[0211] The first-stage pre-emulsion consists of 54 parts of n-butyl acrylate, 2.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0212] The second-stage pre-emulsion consists of 30 parts of styrene, 10 parts of acrylonitrile, 2.5 parts of sodium nonylphenol polyoxyethylene ether phosphate monoester, 0.5 part of allyl methacrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of potassium persulfate and 50 parts of deionized water.

[0213] The remaining steps are the same as those in Example 1.

[0214] The relevant test results of the latexes and resins in Examples 1 to 6 and Comparative Examples 1 to 4 are shown in Table 1.

[0215] Table 1: Relevant test results of latexes and resins

[0216]

[0217] In Table 1, the values of L, a, and b are the values before the weather resistance test.

[0218] As shown in Table 1, the high-solid ASA latexes prepared in Examples 1 to 6 of the present invention have high conversion rates, less precipitation, appropriate particle sizes and adjustable particle sizes. Moreover, due to the strong emulsifying ability of the emulsifier and appropriate dosage, and the very small dosage of the auxiliary agent, the appearance of the processed resin is better and the weather resistance is also better.

[0219] It can be seen from Comparative Example 1 that the introduction of other auxiliary agents in the polymerization stage results in poor appearance properties of the processed resin and deteriorates its weather resistance.

[0220] It can be seen from the comparison between the examples and Comparative Example 2 that the simplified polymerization process of the present invention is simpler than the general ASA polymerization process and has higher production efficiency. In addition, the simplification of the process has no adverse effect on the resin properties. Moreover, due to the shorter polymerization time and the small addition amount of polymerization auxiliary agents, the appearance properties of the resin are also better.

[0221] It can be seen from Comparative Examples 3 and 4 that when the dosage of the special emulsifier used in the polymerization process is too low, the stability of the prepared latex is poor and the precipitation is relatively large; when the dosage of the special emulsifier is too high, although the polymerization stability is better, the demulsification is difficult, and finally the appearance of the processed resin is not good and the weather resistance is also poor.

Claims

1. A method for preparing an acrylate-styrene-acrylonitrile core-shell graft copolymer latex, characterized in that, the method comprises the following steps: (1) In a reaction system containing an acrylate monomer, an emulsifier, a water-soluble initiator and water, polymerize the acrylate monomer to prepare a seed latex; (2) Drop a first-stage pre-emulsion into the seed latex for a diameter-expanding reaction to prepare a diameter-expanded latex, the first-stage pre-emulsion containing an acrylate monomer, an emulsifier, a grafting agent, a cross-linking agent, a water-soluble initiator and water; (3) Drop a second-stage pre-emulsion into the diameter-expanded latex for a grafting reaction to prepare the acrylate-styrene-acrylonitrile core-shell graft copolymer latex, the second-stage pre-emulsion containing a vinyl aromatic monomer, a vinyl nitrile monomer, an emulsifier, a water-soluble initiator and water; wherein, the emulsifier in the reaction system of step (1), the first-stage pre-emulsion and the second-stage pre-emulsion is a nonionic-anionic amphoteric emulsifier.

2. The method according to claim 1, characterized in that, the method has one or more of the following characteristics: The emulsifiers in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion are each independently selected from one or more of polyoxyethylene ether phosphate ester salts and polyoxyethylene ether sulfonate ester salts; preferably, the polyoxyethylene ether phosphate ester salts are selected from one or more of sodium nonylphenol polyoxyethylene ether phosphate monoester and potassium alcohol ether phosphate monoester, and the polyoxyethylene ether sulfonate ester salt is sodium alkylphenol polyoxyethylene ether sulfosuccinate; preferably, the sodium nonylphenol polyoxyethylene ether phosphate monoester has the structure shown in formula I: n is the number of repeating units; In the reaction system of step (1), relative to 100 parts by mass of water, the amount of the acrylate monomer used is 2-6 parts by mass, the amount of the emulsifier used is 1-2 parts by mass, and the amount of the water-soluble initiator used is 0.2-0.4 parts by mass; In step (1), the temperature of the polymerization reaction is 70-80 °C, and the time of the polymerization reaction is 0.5-1 h; In the first-stage pre-emulsion, relative to 50 parts by mass of water, the amount of the acrylate monomer used is 54-58 parts by mass, the amount of the emulsifier used is 1-2 parts by mass, the amount of the grafting agent used is 0.2-1 part by mass, the amount of the cross-linking agent used is 0.2-1 part by mass, and the amount of the water-soluble initiator used is 0.2-0.4 parts by mass; The mass ratio of the acrylate monomer in the reaction system of step (1) to the acrylate monomer in the first-stage pre-emulsion is 2:58 to 6:54; In step (2), the first-stage pre-emulsion is dropped into the seed latex at 70-80 °C; In step (2), the first-stage pre-emulsion is dropped into the seed latex within 1.5-2 h to complete the diameter-expanding reaction; In the second-stage pre-emulsion, relative to 50 parts by mass of water, the amount of the vinyl aromatic monomer used is 25-35 parts by mass, the amount of the vinyl nitrile monomer used is 5-15 parts by mass, the amount of the emulsifier used is 1-2 parts by mass, and the amount of the water-soluble initiator used is 0.2-0.4 parts by mass; The second-stage pre-emulsion includes a grafting agent; preferably, in the second-stage pre-emulsion, relative to 50 parts by mass of water, the amount of the grafting agent used is 0.2-1 part by mass; The second-stage pre-emulsion includes a cross-linking agent; preferably, in the second-stage pre-emulsion, relative to 50 parts by mass of water, the amount of the cross-linking agent used is 0.2-1 part by mass; The sum of the amounts of the acrylate monomers in the reaction system of step (1) and the acrylate monomers in the first-stage pre-emulsion is counted as 60 parts by mass, and the sum of the amounts of the vinyl aromatic monomers and the vinyl nitrile monomers in the second-stage pre-emulsion is 30 - 50 parts by mass; In step (3), the second-stage pre-emulsion is added dropwise to the diameter-expanded latex at 70 - 80 °C; In step (3), the second-stage pre-emulsion is added dropwise to the diameter-expanded latex over 0.5 - 1 h; In step (3), after the addition of the second-stage pre-emulsion is completed, the reaction is continued at 70 - 80 °C until the polymerization conversion rate > 98%; The particle size of the prepared acrylate-styrene-acrylonitrile core-shell graft copolymer latex is 240 - 340 nm.

3. The method according to claim 1, wherein, the method has one or more of the following characteristics: The reaction system of step (1) and the acrylate monomer in the first-stage pre-emulsion are each independently one or more acrylate monomers having a structural formula of CH 2 =CHCOOR 1 , where R 1 is a C1-C15 alkyl group; preferably, the reaction system of step (1) and the acrylate monomer in the first-stage pre-emulsion 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 reaction system of step (1) and the acrylate monomer in the first-stage pre-emulsion are each independently one or more acrylate monomers having a structural formula of CH 2 =CHCOOR 2 , where R 2 is a C1-C4 linear alkyl group, more preferably butyl acrylate; The water-soluble initiators in the reaction system of step (1), the first-stage pre-emulsion, and the second-stage pre-emulsion are each independently selected from one or more of sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide, preferably potassium persulfate; The grafting agent in the first-stage pre-emulsion is one or more compounds containing two or more different unsaturated vinyl functional groups, preferably selected from one or more of allyl methacrylate, triallyl isocyanurate, triallylamine, and diallylamine, more preferably allyl methacrylate; The second-stage pre-emulsion contains a grafting agent, and the grafting agent in the second-stage pre-emulsion is one or more compounds containing two or more different unsaturated vinyl functional groups, preferably selected from one or more of allyl methacrylate, triallyl isocyanurate, triallylamine, and diallylamine, more preferably allyl methacrylate; The crosslinking agent in the first-stage pre-emulsion is one or more compounds containing two or more identical unsaturated vinyl functional groups, preferably selected from one or more of ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, and 1,3-propanediol diacrylate, more preferably ethylene glycol dimethacrylate; The second-stage pre-emulsion contains a crosslinking agent, and the crosslinking agent in the second-stage pre-emulsion is one or more compounds containing two or more identical unsaturated vinyl functional groups, preferably selected from one or more of ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, and 1,3-propanediol diacrylate, more preferably ethylene glycol dimethacrylate; The vinyl aromatic monomer in the second-stage pre-emulsion is selected from one or more of styrene, α-methylstyrene, and p-methylstyrene, preferably styrene; The vinyl nitrile monomer in the second-stage pre-emulsion is selected from one or two of acrylonitrile and methacrylonitrile, preferably acrylonitrile.

4. An acrylate-styrene-acrylonitrile core-shell graft copolymer latex prepared by the method according to any one of claims 1 - 3.

5. An acrylate-styrene-acrylonitrile core-shell graft copolymer, It is characterized in that the acrylate-styrene-acrylonitrile core-shell graft copolymer is prepared from the acrylate-styrene-acrylonitrile core-shell graft copolymer latex described in claim 4.

6. The acrylate-styrene-acrylonitrile core-shell graft copolymer according to claim 5, it is characterized in that the acrylate-styrene-acrylonitrile core-shell graft copolymer is prepared by demulsifying, heating and curing at an elevated temperature, washing and drying the acrylate-styrene-acrylonitrile core-shell graft copolymer latex described in claim 4; preferably, the temperature for heating and curing at an elevated temperature is 90-100 °C, and the time for heating and curing at an elevated temperature is 10-30 min.

7. An acrylate-styrene-acrylonitrile copolymer resin, it is characterized in that the acrylate-styrene-acrylonitrile copolymer resin comprises the acrylate-styrene-acrylonitrile core-shell graft copolymer described in claim 5 or 6 and an acrylonitrile-styrene copolymer; preferably, in the acrylate-styrene-acrylonitrile copolymer resin, the mass ratio of the acrylate-styrene-acrylonitrile core-shell graft copolymer to the acrylonitrile-styrene copolymer is 25:75 to 45:

55.

8. The acrylate-styrene-acrylonitrile copolymer resin according to claim 7, it is characterized in that the acrylate-styrene-acrylonitrile copolymer resin is prepared by blending and extruding a material composition comprising the acrylate-styrene-acrylonitrile core-shell graft copolymer and the acrylonitrile-styrene copolymer.

9. The acrylate-styrene-acrylonitrile copolymer resin according to claim 7, it is characterized in that the material composition further comprises an antioxidant and / or a lubricant. Based on the total mass of the acrylate-styrene-acrylonitrile core-shell graft copolymer and the acrylonitrile-styrene copolymer being 100 parts by mass, 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; and / or the temperature of the extrusion is 180-240 °C.

10. Application of a nonionic-anionic amphoteric emulsifier in the preparation of a polymer latex; Preferably, the nonionic-anionic amphoteric emulsifier is selected from one or more of polyoxyethylene ether sulfonate emulsifiers and polyoxyethylene ether phosphate emulsifier salts; preferably, the polyoxyethylene ether sulfonate emulsifier is sodium alkylphenol polyoxyethylene ether sulfosuccinate, and the polyoxyethylene ether phosphate emulsifier salts are selected from one or more of sodium nonylphenol polyoxyethylene ether phosphate monoester and potassium alcohol ether phosphate monoester; preferably, the sodium nonylphenol polyoxyethylene ether phosphate monoester has the structure shown in Formula I: n is the number of repeating units; preferably, the polymer latex is an acrylate-styrene-acrylonitrile copolymer latex, an acrylonitrile-butadiene-styrene copolymer latex, a styrene-butadiene rubber latex, a chloroprene rubber latex, a polyvinyl chloride latex, a polybutadiene latex, a polyacrylate latex or a polyvinyl acetate latex.

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