Production method of ASA special rubber powder

Abstract

The invention discloses a production method of ASA special rubber powder, and relates to the technical field of chemical production, and the production method comprises the following steps: feeding a composite emulsifier, a first initiator, an auxiliary agent and deionized water into a reaction kettle, and stirring; then adding an acrylate monomer, a cross-linking agent and a grafting agent into the reaction kettle, and continuously feeding nitrogen into the reaction kettle at the same time; stirring and mixing an acrylate monomer, a cross-linking agent, a grafting agent and a second initiator to prepare polyacrylate latex; feeding the polyacrylate latex, a chelating agent, a third initiator, a styrene monomer, an acrylonitrile monomer, a reducing agent and deionized water into a stirring kettle to prepare ASA latex; a surface treating agent, a coagulant, ASA latex, glass fiber powder and deionized water are fed into a coagulation kettle, and the ASA special rubber powder is prepared after spray drying. Therefore, under the action of the cross-linking agent and the grafting agent, the prepared ASA special rubber powder forms a core with a long-chain cross-linked network, and the tensile strength of a final product is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical production, in particular to a method for producing ASA special rubber powder. Background Art

[0002] ASA rubber powder is a plastic modifier with a rubber content of 40-70% obtained by grafting a layer of styrene and acrylonitrile copolymer (SAN) onto the surface of polyacrylate latex through an emulsion grafting reaction, followed by flocculation and drying. ASA rubber powder can be blended with engineering plastics to form alloys, thereby improving the toughness of the plastic. For example, the most common ASA resin is the product of melt blending ASA rubber powder and SAN resin. Common composite materials prepared from ASA rubber powder include PC / ASA alloys, PVC / ASA alloys, PBT / ASA alloys, etc. The core technologies for the preparation of ASA rubber powder include two points: one is the preparation process of the core layer latex polyacrylate latex; the other is the surface grafting of the polyacrylate latex. In recent years, many patents and papers have disclosed the preparation process of ASA rubber powder. For example, patent CN104231185A uses an absorptive anionic surfactant such as alkyl sulfate, alkyl sulfonate, or alkylbenzene sulfonate as an emulsifier to prepare a small-particle polyacrylate latex, which is then subjected to emulsion graft polymerization to produce an ASA latex with a particle size of 160-170 nm. ASA rubber powder is then obtained through flocculation, demulsification, and drying. Patent CN109293842A uses a mixed anionic and nonionic emulsifier to prepare a polyacrylate latex, which is then subjected to flocculation and drying to produce an ASA resin high-impact rubber powder. Patent CN109651571A uses acrylate-modified polyurethane as the initial seed latex, and then uses sodium dodecyl sulfate, sodium dodecyl sulfonate, or sodium dodecylbenzene sulfonate as anionic emulsifiers to prepare a polyacrylate latex. ASA latex with a particle size of 150-230 nm is then grafted to produce the ASA latex. ASA rubber powder is obtained through flocculation and drying, and is mixed with SAN resin to produce a high-impact ASA resin. Patent CN109071737A uses a multifunctional carboxylic acid with more than 20 carbon atoms or its salt as an emulsifier to prepare ASA rubber powder, thereby improving the whiteness of the ASA resin and reducing color difference.

[0003] A summary of currently available methods for preparing ASA rubber powder reveals that the emulsifiers used in the process can be categorized into several types: one is an absorptive anionic emulsifier, typified by sodium lauryl sulfate; another is a mixed emulsifier primarily composed of an absorptive anionic emulsifier supplemented by a nonionic emulsifier; and another is an emulsifier using polyfunctional carboxylic acids or their salts with 20 or more carbon atoms. Emulsifiers are generally small molecules, and their presence directly affects the mechanical and surface properties of the material. In specific applications, their presence can also directly impact the surface gloss and dyeing properties of the material. While the use of polyfunctional carboxylic acids or their salts with 20 or more carbon atoms as emulsifiers, as reported in patent CN109071737A, can address these issues, these emulsifiers are expensive and require a large addition during emulsion polymerization, significantly increasing the production cost of ASA rubber powder. Summary of the Invention

[0004] In view of the above defects, the purpose of the present invention is to provide a method for producing ASA special rubber powder, aiming to solve the problem of high production cost of ASA rubber powder in the prior art.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: A method for producing ASA special rubber powder comprises the following steps: Step 1: Add 1-8 parts of a composite emulsifier, 0.15-2.5 parts of a first initiator, 0.2-2.8 parts of an auxiliary agent, and 55-70 parts of deionized water, by weight, into a reactor and stir until completely dissolved; then add 10-20 parts of an acrylate monomer, 1-3 parts of a crosslinking agent, and 0.2-2.8 parts of a grafting agent into the reactor while continuously introducing nitrogen into the reactor. The temperature in the reactor is 60-80° C., and the reaction time is 30-150 minutes. Step 2: By weight, 40-50 parts of acrylic acid ester monomer, 1.5-3.5 parts of cross-linking agent, 0.5-2.5 parts of grafting agent, and 0.3-2.2 parts of second initiator are stirred and mixed to prepare a primary mixture, and then the primary mixture is added dropwise to the reactor in step 1, while nitrogen is continuously fed in. The temperature in the reactor is adjusted to 50-70° C., and the addition time is 2-5 hours. After the addition is completed, the reaction is continued for 1-2 hours to prepare a polyacrylate latex; Step 3: adding 40-50 parts of polyacrylate latex, 0.2-1.2 parts of chelating agent, 0.5-1.5 parts of third initiator, 15-30 parts of styrene monomer, 5-10 parts of acrylonitrile monomer, 0.1-1.1 parts of reducing agent and 20-30 parts of deionized water to a stirred tank, while continuously introducing nitrogen, the temperature in the stirred tank is 30-50° C., the reaction time is 3-6 hours, and after the reaction is completed, the temperature is raised to 70-80° C. and maintained for 1-2 hours to obtain ASA latex; Step 4: Add 2-3 parts of surface treatment agent, 1.5-2.5 parts of coagulant, 60-70 parts of ASA latex, 8-15 parts of glass fiber powder and 5-10 parts of deionized water into a coagulant kettle and stir and mix for 10-30 minutes. Then adjust the temperature in the coagulant kettle to 50-60°C and keep it warm for 1-2 hours to obtain ASA composite latex. Spray dry the ASA composite latex to obtain ASA special rubber powder.

[0006] Wherein, the composite emulsifier is composed of 10-15 parts of fatty alcohol polyoxyethylene ether sodium sulfate, 50-60 parts of sodium dodecylbenzene sulfonate, 7-10 parts of Tween-80, 0.5-1.5 parts of disodium hydrogen phosphate, and 0.5-1.5 parts of citric acid, in parts by weight.

[0007] Wherein, the auxiliary agent is composed of 30-40 parts of potassium carbonate, 20-30 parts of sodium bicarbonate, 5-10 parts of sodium sulfate, and 10-15 parts of sodium chloride in parts by weight.

[0008] The first initiator is potassium persulfate; the second initiator is composed of a mixture of 60-70 parts of ammonium persulfate and 30-40 parts of sodium bisulfite by weight; and the third initiator is composed of a mixture of 70-80 parts of benzoyl peroxide and 20-30 parts of azobisisobutyronitrile.

[0009] The acrylate monomer is one or a mixture of butyl acrylate, butyl methacrylate, isooctyl acrylate, and ethyl acrylate; the crosslinking agent is composed of a mixture of 50-70 parts by weight of divinylbenzene, 10-20 parts by weight of ethylene glycol dimethacrylate, and 5-10 parts by weight of vinyltriethoxysilane; and the grafting agent is composed of a mixture of 30-40 parts by weight of α-methylstyrene, 40-50 parts by weight of allyl acrylate, and 10-20 parts by weight of N-phenylmaleimide.

[0010] Wherein, the chelating agent is disodium ethylenediaminetetraacetate; and the reducing agent is ferrous sulfate or sodium sulfite.

[0011] Wherein, the surface treatment agent is KH-550 or KH-570.

[0012] Wherein, the coagulant is a magnesium sulfate-ethanol composite coagulant.

[0013] The preparation method of the coagulant is as follows: magnesium sulfate with a water content of ≤0.3wt% is taken, and the magnesium sulfate is crushed into 0.5-1mm; the crushed magnesium sulfate is mixed with deionized water to prepare a saturated magnesium sulfate solution; anhydrous ethanol is then added to the saturated magnesium sulfate solution in three gradient steps, with an interval of 5-8min between each addition, and the total mass ratio of anhydrous ethanol to magnesium sulfate is 1:1.2-1.5, to prepare a mixed solution; sodium polyacrylate with a concentration of 0.05-0.1wt% is added to the mixed solution, the pH value of the mixed solution is adjusted to 6.5-7.0, and the mixed solution is kept warm at 50-60 degrees Celsius and matured for 30-50 minutes to prepare the coagulant; the mass ratio of the added ethanol is 30%:40%:30%.

[0014] Wherein, the particle size of the glass fiber powder is 10-20 μm.

[0015] After adopting the above technical solution, the beneficial effects of the present invention are: Under the action of the cross-linking agent and the grafting agent, the ASA special rubber powder prepared by the present invention forms a core with a long-chain cross-linked network, which can absorb more energy when subjected to stress, greatly improving the tensile strength of the final product and having better mechanical properties. The additionally added glass fiber powder, since glass fiber is a high-temperature resistant material, the heat-resistant temperature of the ASA special rubber powder with added glass fiber powder will be higher than that without glass fiber powder. At the same time, the ASA special rubber powder of the present invention is also added with a surface treatment agent and a composite coagulant, which is beneficial to the dispersion of the ASA special rubber powder, thereby making the mechanical properties of the final product higher and more uniform, and preventing the decline in mechanical properties and uneven heat resistance of the material caused by poor dispersion. In this scheme, a composite emulsifier is used to prepare the ASA rubber powder. The composite emulsifier is composed of multiple types of emulsifiers. Since these emulsifiers are low in cost and easy to obtain, the production cost can be greatly reduced while ensuring the performance of the ASA rubber powder. DETAILED DESCRIPTION

[0016] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] Example: A method for producing ASA special rubber powder comprises the following steps: Step 1: Add 1-8 parts of a composite emulsifier, 0.15-2.5 parts of a first initiator, 0.2-2.8 parts of an auxiliary agent, and 55-70 parts of deionized water, by weight, into a reactor and stir until completely dissolved; then add 10-20 parts of an acrylate monomer, 1-3 parts of a crosslinking agent, and 0.2-2.8 parts of a grafting agent into the reactor while continuously introducing nitrogen into the reactor. The temperature in the reactor is 60-80° C., and the reaction time is 30-150 minutes. Step 2: By weight, 40-50 parts of acrylic acid ester monomer, 1.5-3.5 parts of cross-linking agent, 0.5-2.5 parts of grafting agent, and 0.3-2.2 parts of second initiator are stirred and mixed to prepare a primary mixture, and then the primary mixture is added dropwise to the reactor in step 1, while nitrogen is continuously fed in. The temperature in the reactor is adjusted to 50-70° C., and the addition time is 2-5 hours. After the addition is completed, the reaction is continued for 1-2 hours to prepare a polyacrylate latex; Step 3: adding 40-50 parts of polyacrylate latex, 0.2-1.2 parts of chelating agent, 0.5-1.5 parts of third initiator, 15-30 parts of styrene monomer, 5-10 parts of acrylonitrile monomer, 0.1-1.1 parts of reducing agent and 20-30 parts of deionized water to a stirred tank, while continuously introducing nitrogen, the temperature in the stirred tank is 30-50° C., the reaction time is 3-6 hours, and after the reaction is completed, the temperature is raised to 70-80° C. and maintained for 1-2 hours to obtain ASA latex; Step 4: Add 2-3 parts of surface treatment agent, 1.5-2.5 parts of coagulant, 60-70 parts of ASA latex, 8-15 parts of glass fiber powder and 5-10 parts of deionized water into a coagulant kettle and stir and mix for 10-30 minutes. Then adjust the temperature in the coagulant kettle to 50-60°C and keep it warm for 1-2 hours to obtain ASA composite latex. Spray dry the ASA composite latex to obtain ASA special rubber powder.

[0018] The composite emulsifier consists of 10-15 parts of sodium fatty alcohol polyoxyethylene ether sulfate, 50-60 parts of sodium dodecylbenzene sulfonate, 7-10 parts of Tween-80, 0.5-1.5 parts of disodium hydrogen phosphate, and 0.5-1.5 parts of citric acid.

[0019] Tween-80, also known as sorbitan monooleate polyoxyethylene ether, is made by the polymerization of sorbitan monooleate and ethylene oxide.

[0020] The auxiliary agent consists of 30-40 parts of potassium carbonate, 20-30 parts of sodium bicarbonate, 5-10 parts of sodium sulfate and 10-15 parts of sodium chloride.

[0021] The first initiator is potassium persulfate; the second initiator is composed of a mixture of 60-70 parts of ammonium persulfate and 30-40 parts of sodium bisulfite; and the third initiator is composed of a mixture of 70-80 parts of benzoyl peroxide and 20-30 parts of azobisisobutyronitrile.

[0022] The acrylic acid ester monomer is one or a mixture of butyl acrylate, butyl methacrylate, isooctyl acrylate, and ethyl acrylate; the crosslinking agent is composed of a mixture of 50-70 parts of divinylbenzene, 10-20 parts of ethylene glycol dimethacrylate, and 5-10 parts of vinyltriethoxysilane; and the grafting agent is composed of a mixture of 30-40 parts of α-methylstyrene, 40-50 parts of allyl acrylate, and 10-20 parts of N-phenylmaleimide.

[0023] The chelating agent is disodium ethylenediaminetetraacetate; and the reducing agent is ferrous sulfate or sodium sulfite.

[0024] The surface treatment agent is KH-550 or KH-570.

[0025] The coagulant is a magnesium sulfate-ethanol composite coagulant.

[0026] The preparation method of the coagulant comprises the following steps: taking magnesium sulfate with a water content of ≤0.3wt%, crushing the magnesium sulfate to 0.5-1mm; mixing the crushed magnesium sulfate with deionized water to prepare a saturated magnesium sulfate solution; then adding anhydrous ethanol to the saturated magnesium sulfate solution in three gradient steps, with an interval of 5-8min between each addition, and a total mass ratio of anhydrous ethanol to magnesium sulfate of 1:1.2-1.5, to prepare a mixed solution; adding sodium polyacrylate with a concentration of 0.05-0.1wt% to the mixed solution, adjusting the pH value of the mixed solution to 6.5-7.0, keeping the mixed solution warm at 50-60 degrees Celsius and maturing for 30-50 minutes, to prepare the coagulant; the mass ratio of the added ethanol is 30%:40%:30%.

[0027] The particle size of the glass fiber powder is 10-20 μm.

[0028] Example 1: In this embodiment: Step 1: Add 1 part of composite emulsifier, 0.15 parts of first initiator, 0.2 parts of auxiliary agent and 55 parts of deionized water into a reactor and stir until completely dissolved; then add 10 parts of acrylate monomer, 1 part of cross-linking agent and 0.2 parts of grafting agent into the reactor while continuously introducing nitrogen into the reactor. The temperature in the reactor is 60° C. and the reaction time is 30 minutes. Step 2: 40 parts of acrylic acid ester monomer, 1.5 parts of cross-linking agent, 0.5 parts of grafting agent, and 0.3 parts of second initiator were stirred and mixed by weight to prepare a primary mixture, and then the primary mixture was added dropwise to the reactor in step 1, while nitrogen was continuously fed in. The temperature in the reactor was adjusted to 50° C. The addition time was 2 hours, and after the addition was completed, the reaction was continued for 1 hour to prepare a polyacrylate latex; Step 3: 40 parts of polyacrylate latex, 0.2 parts of chelating agent, 0.5 parts of third initiator, 15 parts of styrene monomer, 5 parts of acrylonitrile monomer, 0.1 parts of reducing agent and 20 parts of deionized water were added to a stirred tank by weight, while nitrogen was continuously introduced. The temperature in the stirred tank was 30° C., the reaction time was 3 h, and after the reaction was completed, the temperature was raised to 70° C. and maintained for 1 h to obtain ASA latex; Step 4: Add 2 parts of surface treatment agent, 1.5 parts of coagulant, 60 parts of ASA latex, 8 parts of glass fiber powder and 5 parts of deionized water into a coagulant kettle and stir and mix for 10 minutes. Then adjust the temperature in the coagulant kettle to 50°C and keep it warm for 1 hour to obtain ASA composite latex. Spray dry the ASA composite latex to obtain ASA special rubber powder.

[0029] The composite emulsifier consists of 10 parts of sodium fatty alcohol polyoxyethylene ether sulfate, 50 parts of sodium dodecylbenzene sulfonate, 7 parts of Tween-80, 0.5 parts of disodium hydrogen phosphate, and 0.5 parts of citric acid.

[0030] The auxiliary agent consists of 30 parts of potassium carbonate, 20 parts of sodium bicarbonate, 5 parts of sodium sulfate and 10 parts of sodium chloride.

[0031] The first initiator is potassium persulfate; the second initiator is composed of a mixture of 60 parts of ammonium persulfate and 30 parts of sodium bisulfite; and the third initiator is composed of a mixture of 70 parts of benzoyl peroxide and 20 parts of azobisisobutyronitrile.

[0032] The acrylate monomer is butyl acrylate; the crosslinking agent is composed of a mixture of 50 parts of divinylbenzene, 10 parts of ethylene glycol dimethacrylate and 5 parts of vinyltriethoxysilane; and the grafting agent is composed of a mixture of 30 parts of α-methylstyrene, 40 parts of allyl acrylate and 10 parts of N-phenylmaleimide.

[0033] The chelating agent is disodium ethylenediaminetetraacetate; and the reducing agent is ferrous sulfate.

[0034] The surface treatment agent is KH-550.

[0035] The coagulant is a magnesium sulfate-ethanol composite coagulant.

[0036] The preparation method of the coagulant comprises the following steps: taking magnesium sulfate with a water content of ≤0.3wt%, crushing the magnesium sulfate to 0.5mm; mixing the crushed magnesium sulfate with deionized water to prepare a saturated magnesium sulfate solution; then adding anhydrous ethanol to the saturated magnesium sulfate solution in three gradient steps, with an interval of 5 minutes between each addition, and a total mass ratio of anhydrous ethanol to magnesium sulfate of 1:1.2, to prepare a mixed solution; adding sodium polyacrylate with a concentration of 0.05wt% to the mixed solution, adjusting the pH value of the mixed solution to 6.5, keeping the mixed solution at 50 degrees Celsius and maturing for 30 minutes, to prepare the coagulant; the mass ratios of the added ethanol are 30%:40%:30%, respectively.

[0037] The particle size of the glass fiber powder is 10 μm.

[0038] Example 2: The difference between this embodiment and embodiment 1 is that: Step 1: Add 2 parts of composite emulsifier, 0.17 parts of first initiator, 0.4 parts of auxiliary agent and 60 parts of deionized water into a reactor and stir until completely dissolved; then add 12 parts of acrylate monomer, 1.2 parts of cross-linking agent and 0.4 parts of grafting agent into the reactor while continuously introducing nitrogen into the reactor. The temperature in the reactor is 62° C. and the reaction time is 45 minutes. Step 2: 42 parts of acrylate monomer, 1.7 parts of cross-linking agent, 0.7 parts of grafting agent, and 0.5 parts of second initiator were stirred and mixed by weight to prepare a primary mixture, and then the primary mixture was added dropwise to the reactor in step 1 while nitrogen was continuously fed in. The temperature in the reactor was adjusted to 52° C. The addition time was 3 hours, and after the addition was completed, the reaction was continued for 1.2 hours to prepare a polyacrylate latex; Step 3: 42 parts of polyacrylate latex, 0.4 parts of chelating agent, 0.7 parts of third initiator, 17 parts of styrene monomer, 7 parts of acrylonitrile monomer, 0.4 parts of reducing agent and 22 parts of deionized water were added to a stirred tank by weight, while nitrogen was continuously introduced. The temperature in the stirred tank was 32° C., the reaction time was 4 hours, and after the reaction was completed, the temperature was raised to 72° C. and maintained for 1.2 hours to obtain ASA latex; Step 4: Add 2.5 parts of surface treatment agent, 2 parts of coagulant, 65 parts of ASA latex, 10 parts of glass fiber powder and 8 parts of deionized water into a coagulant kettle and stir and mix for 15 minutes. Then adjust the temperature in the coagulant kettle to 52°C and keep it warm for 1.5 hours to obtain ASA composite latex. Spray dry the ASA composite latex to obtain ASA special rubber powder.

[0039] The composite emulsifier consists of 12 parts of sodium fatty alcohol polyoxyethylene ether sulfate, 52 parts of sodium dodecylbenzene sulfonate, 9 parts of Tween-80, 0.7 parts of disodium hydrogen phosphate, and 0.7 parts of citric acid.

[0040] The auxiliary agent consists of 32 parts of potassium carbonate, 22 parts of sodium bicarbonate, 7 parts of sodium sulfate and 12 parts of sodium chloride.

[0041] The first initiator is potassium persulfate; the second initiator is composed of a mixture of 62 parts of ammonium persulfate and 32 parts of sodium bisulfite; and the third initiator is composed of a mixture of 72 parts of benzoyl peroxide and 22 parts of azobisisobutyronitrile.

[0042] The acrylate monomer is composed of a mixture of 50 parts of butyl acrylate and 50 parts of butyl methacrylate; the crosslinking agent is composed of a mixture of 50 parts of divinylbenzene, 10 parts of ethylene glycol dimethacrylate and 5 parts of vinyltriethoxysilane; and the grafting agent is composed of a mixture of 30 parts of α-methylstyrene, 40 parts of allyl acrylate and 10 parts of N-phenylmaleimide.

[0043] The chelating agent is disodium ethylenediaminetetraacetate; and the reducing agent is sodium sulfite.

[0044] The surface treatment agent is KH-570.

[0045] The coagulant is a magnesium sulfate-ethanol composite coagulant.

[0046] The preparation method of the coagulant comprises the following steps: taking magnesium sulfate with a water content of ≤0.3wt%, crushing the magnesium sulfate to 0.7mm; mixing the crushed magnesium sulfate with deionized water to prepare a saturated magnesium sulfate solution; then adding anhydrous ethanol to the saturated magnesium sulfate solution in three gradient steps, with an interval of 6 minutes between each addition, and a total mass ratio of anhydrous ethanol to magnesium sulfate of 1:1.3, to prepare a mixed solution; adding sodium polyacrylate with a concentration of 0.07wt% to the mixed solution, adjusting the pH value of the mixed solution to 6.7, keeping the mixed solution at 52 degrees Celsius and maturing for 32 minutes, to prepare the coagulant; the mass ratios of the added ethanol are 30%:40%:30%, respectively.

[0047] The particle size of the glass fiber powder is 12 μm.

[0048] Example 3: The difference between this embodiment and embodiment 1 is that: Step 1: 7 parts of a composite emulsifier, 2.3 parts of a first initiator, 2.5 parts of an auxiliary agent, and 65 parts of deionized water were added to a reactor and stirred until completely dissolved; 18 parts of an acrylate monomer, 2.5 parts of a crosslinking agent, and 2.5 parts of a grafting agent were then added to the reactor while continuously introducing nitrogen into the reactor. The temperature in the reactor was 75° C., and the reaction time was 100 minutes. Step 2: 48 parts of acrylic acid ester monomer, 2.5 parts of cross-linking agent, 2 parts of grafting agent, and 2 parts of second initiator were stirred and mixed by weight to prepare a primary mixture, and then the primary mixture was added dropwise to the reactor in step 1, while nitrogen was continuously fed in. The temperature in the reactor was adjusted to 65° C. The addition time was 4 hours, and after the addition was completed, the reaction was continued for 1.8 hours to prepare a polyacrylate latex; Step 3: 48 parts of polyacrylate latex, 1 part of chelating agent, 1.2 parts of third initiator, 25 parts of styrene monomer, 8 parts of acrylonitrile monomer, 0.8 part of reducing agent and 25 parts of deionized water were added to a stirred tank by weight, while nitrogen was continuously introduced. The temperature in the stirred tank was 45° C., the reaction time was 5 h, and after the reaction was completed, the temperature was raised to 75° C. and maintained for 1.5 h to obtain ASA latex; Step 4: 2.8 parts of surface treatment agent, 2.2 parts of coagulant, 68 parts of ASA latex, 13 parts of glass fiber powder and 8 parts of deionized water are added into a coagulant kettle and stirred for 22 minutes. The temperature in the coagulant kettle is then adjusted to 58°C and kept warm for 1.8 hours to obtain an ASA composite latex. The ASA composite latex is spray-dried to obtain an ASA special rubber powder.

[0049] The composite emulsifier consists of 14 parts of sodium fatty alcohol polyoxyethylene ether sulfate, 55 parts of sodium dodecylbenzene sulfonate, 9 parts of Tween-80, 1.2 parts of disodium hydrogen phosphate, and 1.2 parts of citric acid.

[0050] The auxiliary agent consists of 35 parts of potassium carbonate, 25 parts of sodium bicarbonate, 8 parts of sodium sulfate and 12 parts of sodium chloride.

[0051] The first initiator is potassium persulfate; the second initiator is composed of a mixture of 68 parts of ammonium persulfate and 38 parts of sodium bisulfite; and the third initiator is composed of a mixture of 78 parts of benzoyl peroxide and 28 parts of azobisisobutyronitrile.

[0052] The acrylate monomer is composed of a mixture of 20 parts of butyl acrylate, 30 parts of butyl methacrylate, 10 parts of isooctyl acrylate, and 40 parts of ethyl acrylate; the crosslinking agent is composed of a mixture of 65 parts of divinylbenzene, 18 parts of ethylene glycol dimethacrylate, and 8 parts of vinyltriethoxysilane; and the grafting agent is composed of a mixture of 38 parts of α-methylstyrene, 48 parts of allyl acrylate, and 18 parts of N-phenylmaleimide.

[0053] The chelating agent is disodium ethylenediaminetetraacetate; and the reducing agent is ferrous sulfate.

[0054] The surface treatment agent is KH-550.

[0055] The coagulant is a magnesium sulfate-ethanol composite coagulant.

[0056] The preparation method of the coagulant comprises the following steps: taking magnesium sulfate with a water content of ≤0.3wt%, crushing the magnesium sulfate to 0.5-1mm; mixing the crushed magnesium sulfate with deionized water to prepare a saturated magnesium sulfate solution; then adding anhydrous ethanol to the saturated magnesium sulfate solution in three gradient steps, with an interval of 7 minutes between each addition, and a total mass ratio of anhydrous ethanol to magnesium sulfate of 1:1.4, to prepare a mixed solution; adding sodium polyacrylate with a concentration of 0.05-0.1wt% to the mixed solution, adjusting the pH value of the mixed solution to 6.8, keeping the mixed solution at 58 degrees Celsius and maturing for 45 minutes to prepare the coagulant; the mass ratio of the added ethanol is 30%:40%:30%.

[0057] The particle size of the glass fiber powder is 18 μm.

[0058] Example 4: The difference between this embodiment and embodiment 1 is that: Step 1: 8 parts of a composite emulsifier, 2.5 parts of a first initiator, 2.8 parts of an auxiliary agent, and 70 parts of deionized water were added to a reactor and stirred until completely dissolved; 20 parts of an acrylate monomer, 3 parts of a cross-linking agent, and 2.8 parts of a grafting agent were then added to the reactor while continuously introducing nitrogen into the reactor. The temperature in the reactor was 80° C., and the reaction time was 150 min. Step 2: 50 parts of acrylic acid ester monomer, 3.5 parts of cross-linking agent, 2.5 parts of grafting agent, and 2.2 parts of second initiator were stirred and mixed by weight to prepare a primary mixture, and then the primary mixture was added dropwise to the reactor in step 1, while nitrogen was continuously fed in. The temperature in the reactor was adjusted to 70° C. The addition time was 5 hours, and after the addition was completed, the reaction was continued for 2 hours to prepare a polyacrylate latex; Step 3: 50 parts of polyacrylate latex, 1.2 parts of chelating agent, 1.5 parts of third initiator, 30 parts of styrene monomer, 10 parts of acrylonitrile monomer, 1.1 parts of reducing agent and 30 parts of deionized water were added to a stirred tank by weight, while nitrogen was continuously introduced. The temperature in the stirred tank was 50° C., the reaction time was 6 hours, and after the reaction was completed, the temperature was raised to 80° C. and maintained for 2 hours to obtain ASA latex; Step 4: 3 parts of surface treatment agent, 2.5 parts of coagulant, 70 parts of ASA latex, 15 parts of glass fiber powder and 10 parts of deionized water are added into a coagulant kettle and stirred for 30 minutes. Then, the temperature in the coagulant kettle is adjusted to 60°C and kept warm for 2 hours to obtain ASA composite latex. The ASA composite latex is spray-dried to obtain ASA special rubber powder.

[0059] The composite emulsifier consists of 15 parts of sodium fatty alcohol polyoxyethylene ether sulfate, 60 parts of sodium dodecylbenzene sulfonate, 10 parts of Tween-80, 1.5 parts of disodium hydrogen phosphate, and 1.5 parts of citric acid.

[0060] The auxiliary agent consists of 40 parts of potassium carbonate, 30 parts of sodium bicarbonate, 10 parts of sodium sulfate and 15 parts of sodium chloride.

[0061] The first initiator is potassium persulfate; the second initiator is composed of a mixture of 70 parts of ammonium persulfate and 40 parts of sodium bisulfite; and the third initiator is composed of a mixture of 80 parts of benzoyl peroxide and 30 parts of azobisisobutyronitrile.

[0062] The acrylate monomer is ethyl acrylate; the crosslinking agent is composed of a mixture of 70 parts of divinylbenzene, 20 parts of ethylene glycol dimethacrylate and 10 parts of vinyltriethoxysilane; and the grafting agent is composed of a mixture of 40 parts of α-methylstyrene, 50 parts of allyl acrylate and 20 parts of N-phenylmaleimide.

[0063] The chelating agent is disodium ethylenediaminetetraacetate; and the reducing agent is sodium sulfite.

[0064] The surface treatment agent is KH-570.

[0065] The coagulant is a magnesium sulfate-ethanol composite coagulant.

[0066] The preparation method of the coagulant comprises the following steps: taking magnesium sulfate with a water content of ≤0.3wt%, crushing the magnesium sulfate to 1mm; mixing the crushed magnesium sulfate with deionized water to prepare a saturated magnesium sulfate solution; then adding anhydrous ethanol to the saturated magnesium sulfate solution in three gradient steps, with an interval of 8 minutes between each addition, and a total mass ratio of anhydrous ethanol to magnesium sulfate of 1:1.5, to prepare a mixed solution; adding sodium polyacrylate with a concentration of 0.1wt% to the mixed solution, adjusting the pH value of the mixed solution to 7.0, keeping the mixed solution warm at 60 degrees Celsius and maturing for 50 minutes, to prepare the coagulant; the mass ratios of the added ethanol are 30%:40%:30%, respectively.

[0067] The particle size of the glass fiber powder is 20 μm.

[0068] Comparative Example 1: The difference between this comparative example and Example 1 is that step 4 is omitted.

[0069] Comparative Example 2: The difference between this comparative example and Example 1 is that no surface treatment agent is used in step 4.

[0070] Comparative Example 3: The difference between the comparative example and Example 1 is that no coagulant is used in step 4.

[0071] The products of Examples 1-4 and Comparative Examples 1-3 were selected and the average particle size and distribution of the ASA latex obtained in the above Examples and Comparative Examples were measured using a dynamic light scattering laser particle size analyzer (Malvern, ZS-90). The initial whiteness of the ASA rubber powder obtained in the above Examples and Comparative Examples and the whiteness after air aging at 200°C for 1 hour were measured using a whiteness meter. The heat deformation temperature was measured according to the test method provided in ASTM D648, under the test conditions of 1.8 MPa and without annealing. The tensile strength was measured according to the test standard GB / T1040-2006, and the test results are summarized in the following table:

[0072] It can be seen from the above table that after adding glass fiber powder, the ASA rubber powder finished product can effectively improve the heat deformation temperature and tensile strength of the plastic.

[0073] In summary, the advantages of this solution are: under the action of the cross-linking agent and the grafting agent, the ASA special rubber powder prepared by the present invention forms a core with a long-chain cross-linked network, which can absorb more energy when subjected to stress, greatly improving the tensile strength of the final product and having better mechanical properties. The additionally added glass fiber powder, since glass fiber is a high-temperature resistant material, the heat-resistant temperature of the ASA special rubber powder with added glass fiber powder will be higher than that without the addition. At the same time, the ASA special rubber powder of the present invention is also added with a surface treatment agent and a composite coagulant, which is beneficial to the dispersion of the ASA special rubber powder, thereby making the mechanical properties of the final product higher and more uniform, and preventing the decline in mechanical properties and uneven heat resistance of the material caused by poor dispersion. In this solution, a composite emulsifier is used to prepare the ASA rubber powder. The composite emulsifier is composed of multiple types of emulsifiers. Since these emulsifiers are low in cost and easy to obtain, the production cost can be greatly reduced while ensuring the performance of the ASA rubber powder.

[0074] The present invention is not limited to the above-mentioned specific implementation methods. Various changes made by ordinary technicians in this field based on the above-mentioned concept without creative work are all within the scope of protection of the present invention.

Claims

1. A method for producing ASA special rubber powder, characterized in that: The following steps are involved: Step 1: by weight, 1-8 parts of composite emulsifier, 0.15-2.5 parts of first initiator, 0.2-2.8 parts of auxiliary agent and 55-70 parts of deionized water are added into a reactor and stirred until completely dissolved; then 10-20 parts of acrylate monomer, 1-3 parts of crosslinking agent and 0.2-2.8 parts of grafting agent are added into the reactor, and nitrogen is continuously introduced into the reactor at the same time, the temperature in the reactor is 60-80° C., and the reaction time is 30-150 min; Step 2: 40-50 parts of acrylic acid ester monomer, 1.5-3.5 parts of cross-linking agent, 0.5-2.5 parts of grafting agent and 0.3-2.2 parts of second initiator are stirred and mixed by weight to prepare a primary mixture, and then the primary mixture is added dropwise to the reactor in step 1, nitrogen is kept introduced, the temperature in the reactor is adjusted to 50-70° C., the dropping time is 2-5 hours, and the reaction is continued for 1-2 hours after the dropping is completed to prepare a polyacrylate latex; Step 3, by weight, 40-50 parts of polyacrylate latex, 0.2-1.2 parts of chelating agent, 0.5-1.5 parts of third initiator, 15-30 parts of styrene monomer, 5-10 parts of acrylonitrile monomer, 0.1-1.1 parts of reducing agent and 20-30 parts of deionized water are sent to a stirring tank, and nitrogen is continuously introduced at the same time. The temperature in the stirring tank is 30-50° C., the reaction time is 3-6 hours, and the temperature is raised to 70-80° C. after the reaction is completed, and maintained for 1-2 hours to obtain ASA latex; Step 4: Add 2-3 parts of surface treatment agent, 1.5-2.5 parts of coagulant, 60-70 parts of ASA latex, 8-15 parts of glass fiber powder and 5-10 parts of deionized water into a coagulation kettle and stir and mix for 10-30 minutes, then adjust the temperature in the coagulation kettle to 50-60°C and keep it warm for 1-2 hours to obtain ASA composite latex, and spray dry the ASA composite latex to obtain ASA special rubber powder.

2. The method for producing ASA special rubber powder according to claim 1, characterized in that: In terms of weight, the composite emulsifier is composed of 10-15 parts of sodium fatty alcohol polyoxyethylene ether sulfate, 50-60 parts of sodium dodecylbenzene sulfonate, 7-10 parts of Tween-80, 0.5-1.5 parts of disodium hydrogen phosphate, and 0.5-1.5 parts of citric acid.

3. The method for producing ASA special rubber powder according to claim 1, characterized in that: In terms of weight, the auxiliary agent is composed of 30-40 parts of potassium carbonate, 20-30 parts of sodium bicarbonate, 5-10 parts of sodium sulfate, and 10-15 parts of sodium chloride.

4. The method for producing ASA special rubber powder according to claim 1, characterized in that: The first initiator is potassium persulfate; the second initiator is composed of a mixture of 60-70 parts of ammonium persulfate and 30-40 parts of sodium bisulfite by weight; and the third initiator is composed of a mixture of 70-80 parts of benzoyl peroxide and 20-30 parts of azobisisobutyronitrile.

5. The method for producing ASA special rubber powder according to claim 1, characterized in that: The acrylic acid ester monomer is one or a mixture of butyl acrylate, butyl methacrylate, isooctyl acrylate, and ethyl acrylate; the crosslinking agent is composed of a mixture of 50-70 parts of divinylbenzene, 10-20 parts of ethylene glycol dimethacrylate, and 5-10 parts of vinyl triethoxysilane by weight; the grafting agent is composed of a mixture of 30-40 parts of α-methylstyrene, 40-50 parts of allyl acrylate, and 10-20 parts of N-phenylmaleimide by weight.

6. The method for producing ASA special rubber powder according to claim 1, characterized in that: The chelating agent is disodium ethylenediaminetetraacetate; and the reducing agent is ferrous sulfate or sodium sulfite.

7. The method for producing ASA special rubber powder according to claim 1, characterized in that: The surface treatment agent is KH-550 or KH-570.

8. The method for producing ASA special rubber powder according to claim 1, characterized in that: The coagulant is a magnesium sulfate-ethanol composite coagulant.

9. The method for producing ASA special rubber powder according to claim 8, characterized in that: The preparation method of the coagulant is as follows: taking magnesium sulfate with a water content of ≤0.3wt%, crushing the magnesium sulfate to 0.5-1mm; mixing the crushed magnesium sulfate with deionized water to obtain a saturated magnesium sulfate solution, then adding anhydrous ethanol to the saturated magnesium sulfate solution three times in a gradient manner, each addition interval is 5-8min, the total mass ratio of anhydrous ethanol to magnesium sulfate is 1:1.2-1.5, to obtain a mixed solution; adding sodium polyacrylate with a concentration of 0.05-0.1wt% to the mixed solution, adjusting the pH value of the mixed solution to 6.5-7.0, keeping the temperature at 50-60 degrees Celsius and ripening for 30-50min to obtain a coagulant; the mass ratio of ethanol addition is 30%:40%:30% respectively.

10. The method for producing ASA special rubber powder according to claim 1, characterized in that: The particle size of the glass fiber powder is 10-20 μm.

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