ASA (acrylonitrile-styrene-acrylate) resin with high impact resistance, heat resistance grade and whiteness and preparation method of ASA resin

Abstract

The invention discloses ASA resin with high impact resistance, heat resistance grade and high whiteness and a preparation method thereof, and belongs to the technical field of synthetic resin. The ASA resin comprises the following raw materials in parts by weight: 30-40 parts of ASA high rubber powder and 60-70 parts of SAN resin, the preparation method specifically comprises the following steps: (1) weighing the raw materials; (2) preparing modified nano silicon dioxide particles; (3) preparation of polyacrylate latex; (4) preparing ASA high rubber powder; and (5) preparing the ASA resin. The nanoscale silicon dioxide is added, so that silicon dioxide particles can disperse stress to a certain extent in the process that the ASA resin is subjected to external force, stress concentration is avoided to a certain extent, and the impact resistance of the ASA resin is improved. In addition, due to low refractive index and excellent heat resistance of silicon dioxide, the prepared ASA resin also has relatively high whiteness and relatively good heat resistance.

Description

Technical Field

[0001] This invention relates to the field of synthetic resin technology, and more specifically to a high-impact, heat-resistant, high-whiteness ASA resin and its preparation method. Background Technology

[0002] ASA resin, also known as weather-resistant ABS resin, is a core-shell toughening agent (SAN resin) consisting of polyacrylate rubber as the core and styrene-acrylonitrile copolymer as the shell. It is widely used in automotive manufacturing, home appliances, and electrical and electronic fields. Besides its excellent weather resistance, it also possesses superior mechanical properties and solvent resistance. The rubber phase in ASA resin is acrylate rubber, thus lacking carbon-carbon double bonds, which contributes to its excellent weather resistance. However, because polyacrylate rubber has a relatively high glass transition temperature (generally around -50℃), its impact resistance is slightly lower than that of ABS resin. During the preparation of ASA resin, the amount of rubber used is usually increased to improve its impact resistance. For example, the rubber content in ABS resin is generally 13-18 wt%, while in ASA resin it is generally controlled at 18-27 wt%, significantly higher than the rubber content in ABS resin. Especially in the high-impact ASA resin production process, the rubber content is generally above 20 wt%. While increasing the rubber content of ASA resin significantly improves its mechanical properties, it also leads to a decrease in the heat resistance of ASA resin. Specifically, the heat distortion temperature and Vicat softening point of ASA resin will both decrease significantly, which limits the practical application of ASA resin. Developing heat-resistant ASA resin is crucial to meeting the needs of industrial development.

[0003] In recent years, the preparation technology of heat-resistant ASA resin has developed rapidly. For example, patent CN 111138610 A discloses a high-impact, high-heat-resistant ASA resin and its preparation method. The core of this method lies in the physical blending of ASA emulsion and high-heat-resistant AMS (a copolymer of α-methylstyrene and acrylonitrile) emulsion, followed by co-flocculation to prepare the ASA resin. The improved heat resistance is essentially achieved by using α-methylstyrene to replace the styrene monomer, increasing the steric hindrance of the aromatic ring to enhance its rigidity, thereby increasing its heat resistance. The advantage of this method is that it employs emulsion blending and co-flocculation, improving the mixing effect.

[0004] Invention patent CN 120118446 A discloses a method for preparing heat-resistant ASA high-adhesion powder, which involves copolymerizing maleimide monomers containing siloxane groups into the core or shell layer of ASA latex particles to improve heat resistance. The advantage of this method is that the siloxane-containing maleimide monomers significantly improve heat resistance; the disadvantage is that these monomers are expensive, resulting in extremely high costs during industrialization. N-Phenylonimide is a widely used heat-resistant monomer in industry. It is typically copolymerized with styrene, acrylonitrile, and maleimide monomers through bulk polymerization, solution polymerization, and suspension polymerization to prepare heat-resistant grades. Then, the heat-resistant agent is melt-blended with ABS resin or ASA resin to prepare heat-resistant ABS resin and ASA resin. However, these monomers can cause the prepared heat-resistant resin to yellow. Therefore, how to prepare an ASA resin with excellent heat resistance and high whiteness has been a major focus of industry.

[0005] Generally, inorganic particles possess strong rigidity characteristics. Blending inorganic particles with resins can significantly increase the rigidity and heat resistance of polymer resins. Furthermore, if the inorganic particles are small enough, they can also toughen the resin. The mechanism is that when inorganic particles are added to the polymer, during stress concentration caused by external impact, the inorganic particles can disperse the stress to a certain extent, thereby slowing down the occurrence of polymer cracks caused by stress concentration, thus achieving the purpose of toughening. However, ensuring that the inorganic particles do not aggregate and are uniformly dispersed within the polymer resin is crucial to determining its performance.

[0006] Therefore, how to develop a high-performance heat-resistant ASA resin is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention improves the heat resistance of ASA resin by introducing nano-sized inorganic materials. Furthermore, because the refractive index of the inorganic nanoparticles differs significantly from that of the matrix ASA resin, its whiteness is also improved. The core of this invention is how to uniformly disperse the inorganic particles within the ASA resin matrix while ensuring that they do not agglomerate within the resin. To solve the above problems, the present invention employs an in-situ polymerization method. Nano-sized silica is modified using a silane coupling agent, then used as a seed for emulsion polymerization. Soft monomers such as acrylates are used to expand its diameter. Finally, a rigid styrene-acrylonitrile copolymer layer is grafted onto the surface of polyacrylate using emulsion graft polymerization technology, forming a three-layer core-shell structure particle with nano-sized silica as the core, polyacrylate rubber as the intermediate layer, and polystyrene-acrylonitrile copolymer as the shell. The obtained three-layer structure particle is then melt-blended with commercial-grade styrene-acrylonitrile copolymer (SAN resin) to obtain a heat-resistant, high-impact, and high-whiteness ASA resin.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A high-impact, heat-resistant, and high-whiteness ASA resin comprises the following raw materials in parts by weight: 30-40 parts of high-adhesion ASA powder and 60-70 parts of SAN resin; ASA high-polymer powder comprises the following raw materials in parts by weight: 40-60 parts polyacrylate latex, 1-5 parts reducing agent solution, 15-30 parts styrene monomer, 10-15 parts acrylonitrile monomer, and 0.5-2 parts peroxide initiator; Polyacrylate latex comprises the following raw materials in parts by weight: 1-5 parts modified nano silica particles, 40-60 parts deionized water, 1-5 parts emulsifier, 0.2-2 parts initiator, 40-60 parts acrylate monomer, 1-5 parts crosslinking agent and 1-5 parts grafting agent. The modified nano silica particles consist of the following raw materials in parts by weight: 3-5 parts nano silica, 80-90 parts organic solvent, 1-5 parts silane coupling agent, and 5-15 parts organic amine.

[0009] Furthermore, the aforementioned high-impact, heat-resistant, and high-whiteness ASA resin comprises the following raw materials in parts by weight: 40 parts of ASA high-adhesion powder and 60 parts of SAN resin. ASA high-polymer powder comprises the following raw materials in parts by weight: 60 parts polyacrylate latex, 1 part reducing agent solution, 30 parts styrene monomer, 10 parts acrylonitrile monomer and 0.5 parts peroxide initiator; The polyacrylate latex comprises the following raw materials in parts by weight: 1 part modified nano silica particles, 60 parts deionized water, 1 part emulsifier, 0.2 parts initiator, 40 parts acrylate monomer, 1 part crosslinking agent and 1 part grafting agent. The modified nano-silica particles consist of the following raw materials in parts by weight: 5 parts nano-sized silica, 80 parts organic solvent, 5 parts silane coupling agent, and 15 parts organic amine.

[0010] Furthermore, the aforementioned high-impact, heat-resistant, and high-whiteness ASA resin comprises the following raw materials in parts by weight: 40 parts of ASA high-adhesion powder and 60 parts of SAN resin. ASA high-polymer powder comprises the following raw materials in parts by weight: 60 parts polyacrylate latex, 5 parts reducing agent solution, 30 parts styrene monomer, 10 parts acrylonitrile monomer, and 0.5 parts peroxide initiator; The polyacrylate latex comprises the following raw materials in parts by weight: 5 parts modified nano silica particles, 60 parts deionized water, 5 parts emulsifier, 0.2 parts initiator, 40 parts acrylate monomer, 1 part crosslinking agent and 1 part grafting agent. The modified nano-silica particles consist of the following raw materials in parts by weight: 5 parts nano-sized silica, 80 parts organic solvent, 5 parts silane coupling agent, and 5 parts organic amine.

[0011] Furthermore, the aforementioned high-impact, heat-resistant, and high-whiteness ASA resin comprises the following raw materials in parts by weight: 40 parts of ASA high-adhesion powder and 60 parts of SAN resin. ASA high-polymer powder comprises the following raw materials in parts by weight: 60 parts polyacrylate latex, 3 parts reducing agent solution, 25 parts styrene monomer, 15 parts acrylonitrile monomer, and 0.5 parts peroxide initiator; The polyacrylate latex comprises the following raw materials in parts by weight: 2.5 parts modified nano silica particles, 60 parts deionized water, 3 parts emulsifier, 2 parts initiator, 40 parts acrylate monomer, 1 part crosslinking agent and 2 parts grafting agent. The modified nano-silica particles consist of the following raw materials in parts by weight: 3 parts nano-sized silica, 80 parts organic solvent, 3 parts silane coupling agent, and 5 parts organic amine.

[0012] Furthermore, the aforementioned high-impact, heat-resistant, and high-whiteness ASA resin comprises the following raw materials in parts by weight: 40 parts of ASA high-adhesion powder and 60 parts of SAN resin. ASA high-polymer powder comprises the following raw materials in parts by weight: 60 parts polyacrylate latex, 5 parts reducing agent solution, 25 parts styrene monomer, 15 parts acrylonitrile monomer and 0.5 parts peroxide initiator; The polyacrylate latex comprises the following raw materials in parts by weight: 2.5 parts modified nano silica particles, 60 parts deionized water, 3 parts emulsifier, 0.5 parts initiator, 40 parts acrylate monomer, 1 part crosslinking agent, and 5 parts grafting agent. The modified nano-silica particles consist of the following raw materials in parts by weight: 3 parts nano-sized silica, 80 parts organic solvent, 3 parts silane coupling agent, and 5 parts organic amine.

[0013] Furthermore, the size of the aforementioned nano-silica is 5-100 nm; The organic solvent is at least one of toluene, ethylbenzene, and xylene, preferably toluene; Silane coupling agents refer to silane coupling agents containing carbon-carbon double bonds in their structure, preferably at least one of vinyltris(2-methoxyethoxy)silane (KH172) and γ-methacryloyloxypropyltrimethoxysilane (KH570); The organic amine is at least one of diethylamine and triethylamine.

[0014] The further beneficial effects of the above-mentioned method are that the present invention uses inorganic nanoparticle silica as the core of ASA graft copolymerization, which can disperse stress and improve the heat resistance of ASA resin. Furthermore, because the refractive index of silica itself is much different from that of the polymer resin matrix, the whiteness of the prepared ASA resin can be effectively improved.

[0015] Furthermore, the emulsifier mentioned above is at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate; The initiator is at least one of potassium persulfate, sodium persulfate, and ammonium persulfate; The acrylate monomer is at least one of n-butyl acrylate, isobutyl acrylate, isooctyl acrylate, and ethyl acrylate; The crosslinking agent is at least one of ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, and 1,4-butanediol diacrylate; The grafting agent is one of allyl methacrylate, triallyl cyanurate, and triallyl isocyanurate.

[0016] Furthermore, the reducing agent solution mentioned above is a solution prepared by disodium EDTA, ferrous sulfate, sodium formaldehyde sulfoxylate, and deionized water in a mass ratio of 0.02:0.01:0.1:10; wherein, sodium formaldehyde sulfoxylate, also known as sodium formaldehyde sulfoxylate, is prepared by combining formalin with sodium bisulfite and then reducing it, and its chemical name is sodium formaldehyde sulfoxylate, with the chemical formula CH2(OH)SO2Na.

[0017] The peroxide initiator is at least one of cumene hydroperoxide, dicumene hydroperoxide, cyclohexane hydroperoxide, tert-butanol hydroperoxide, and di-tert-butyl hydroperoxide.

[0018] A method for preparing a high-impact, heat-resistant, and high-whiteness ASA resin specifically includes the following steps: (1) Weigh each raw material Weigh each raw material according to the above-mentioned high-impact, heat-resistant, and high-whiteness ASA resin in the specified weight proportions; (2) Preparation of modified nano-silica particles Nanoscale silica and organic solvent were dispersed in an organic solvent, a silane coupling agent and an organic amine were added, the mixture was heated to react, the precipitate was separated, washed and dried to obtain modified silica nanoparticles. (3) Preparation of polyacrylate latex Modified nano-silica particles were dispersed in deionized water and emulsifier, heated, and an initiator was added. Then, acrylate monomers, crosslinking agents and grafting agents were added, and the reaction was heated to obtain polyacrylate latex. (4) Preparation of ASA high-colloid powder The polyacrylate latex is heated, and a reducing agent solution, styrene monomer, 5-10 parts of acrylonitrile monomer and peroxide initiator are added. The reaction is carried out by heating, flocculation and demulsification are performed, centrifugation is carried out, washing is carried out, and drying is carried out to obtain ASA high-rubber powder. (5) Preparation of ASA resin ASA high-binder powder and SAN resin are extruded and granulated to obtain high-impact, heat-resistant, and high-whiteness ASA resin.

[0019] Furthermore, in step (2) above, the temperature of the heating reaction is 100-130℃, and the time is 3-5h; the washing reagents are ethanol, acidified water, and deionized water; the drying temperature is 40-60℃. Among them, the acidified water is deionized water acidified using HCl, and the HCl concentration in the acidified water is between 0.1% and 5%.

[0020] Furthermore, in step (3) above, the temperature is raised to 60-75℃; the temperature of the heating reaction is 80-85℃, and the time is 1-2h.

[0021] Furthermore, in step (4) above, the temperature is raised to 40-70℃; the temperature of the heating reaction is 75-85℃, and the time is 1-2h; the flocculation and demulsification reagent is a 5-20 wt% flocculant solution; and the washing reagent is deionized water. Among them, the flocculant is at least one of magnesium sulfate and calcium chloride.

[0022] Furthermore, in step (5) above, the extrusion granulation equipment is a twin-screw extruder with a temperature of 220-240℃.

[0023] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows: This invention utilizes silane coupling agent-modified nano-silica as the inner core, polyacrylate rubber as the middle layer, and a styrene-acrylonitrile copolymer as the shell. This three-layer structure of impact modifier (ASA high-rubber powder) is melt-blended with SAN resin. The addition of nano-sized silica allows the silica particles to disperse stress to a certain extent during external force application, preventing stress concentration and thus improving the impact resistance of the ASA resin. Furthermore, due to the low refractive index and excellent heat resistance of silica, the prepared ASA resin also possesses high whiteness and good heat resistance. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 The preparation method of high-impact, heat-resistant, and high-whiteness ASA resin specifically includes the following steps: (1) Preparation of modified nano-silica particles After purging the polymerization reactor equipped with stirring and ultrasonic functions twice with nitrogen, 5g of nano-sized silica (particle size 7-40 nm, hydrophobic, Shanghai Aladdin Reagent Co., Ltd.) and 80g of organic solvent toluene were added. The ultrasonic (120W power) and stirring (120rpm) were turned on to ensure that the nano-silica was evenly dispersed in the organic solvent toluene. Then, 5g of silane coupling agent KH570 and 5g of ethylenediamine were added and mixed thoroughly. The reactor temperature was raised to 100℃ and reacted for 5h. The obtained product was separated using a high-speed centrifuge (10000rpm, 30min). The precipitate separated by centrifugation was repeatedly washed with ethanol, acidified water and deionized water. The product was then dried at 40℃ to obtain silane coupling agent modified silica nanoparticles. (2) Preparation of polyacrylate latex Add 1g of modified nano-silica particles to a polymerization reactor, add 60g of deionized water, then add 1g of sodium dodecyl sulfate emulsifier, turn on the stirrer and ultrasonic device (120W) to ensure that the modified nano-silica is evenly dispersed; then heat the reactor to 60℃, stop the ultrasonication, add 0.2g of potassium persulfate initiator to the reactor, and then start adding 40g of acrylate monomer n-butyl acrylate, while simultaneously adding 1g of crosslinking agent ethylene glycol dimethacrylate and 1g of grafting agent allyl methacrylate. Control the adding time to 2h. After the adding is completed, heat the reactor to 80℃ and keep it at that temperature for 1h to obtain polyacrylate latex with nano-silica as the core layer; (3) Preparation of ASA high-colloid powder Add 60g of polyacrylate latex (based on polymer content) to a reactor and heat to 40℃. Then, add 1g of a pre-prepared reducing agent solution to the reactor, followed by the dropwise addition of 30g of styrene monomer, 10g of acrylonitrile monomer, and 0.5g of dicumyl peroxide (a peroxide initiator) over a period of 1 hour. After the addition is complete, heat to 75℃ and maintain the temperature for 1 hour to obtain ASA latex with a three-layer structure. Add a 5 wt% calcium chloride flocculant solution to the ASA latex to cause flocculation and demulsification, then centrifuge and wash twice with deionized water to obtain a wet powder of high-polymer ASA. Dry the wet powder of high-polymer ASA in an oven at 65℃ to obtain high-polymer ASA powder. (4) Preparation of ASA resin By extruding and granulating 40g of high-impact ASA powder and 60g of SAN resin (Chimei, grade 138H) using a twin-screw extruder at 220℃, high-impact, heat-resistant, and high-whiteness ASA resin can be obtained.

[0026] Example 2 The preparation method of high-impact, heat-resistant, and high-whiteness ASA resin specifically includes the following steps: (1) Preparation of modified nano-silica particles After purging the polymerization reactor equipped with stirring and ultrasonic functions with nitrogen three times, 5g of nano-sized silica (particle size 7-40 nm, hydrophobic, Shanghai Aladdin Reagent Co., Ltd.) and 80g of organic solvent toluene were added. The ultrasonic (120W power) and stirring (120rpm) were turned on to ensure that the nano-silica was evenly dispersed in the organic solvent toluene. Then, 5g of silane coupling agent KH 172 and 5g of triethylamine were added and mixed thoroughly. The reactor temperature was raised to 130℃ and reacted for 3h. The obtained product was separated using a high-speed centrifuge (10000rpm, 30min). The precipitate separated by centrifugation was repeatedly washed with ethanol, acidified water and deionized water. The product was then dried at 60℃ to obtain silane coupling agent modified silica nanoparticles. (2) Preparation of polyacrylate latex Add 5g of modified nano-silica particles to a polymerization reactor, add 60g of deionized water, then add 5g of sodium dodecyl sulfonate emulsifier, turn on the stirrer and ultrasonic device (120W) to ensure that the modified nano-silica is evenly dispersed; then heat the reactor to 65℃, stop the ultrasonication, add 0.2g of potassium persulfate initiator to the reactor, and then start adding 40g of acrylate monomer n-butyl acrylate, while simultaneously adding 1g of crosslinking agent diethylene glycol dimethacrylate and 1g of grafting agent triallyl cyanurate. Control the adding time to 5h. After the adding is completed, heat the reactor to 80℃ and keep it at that temperature for 1h to obtain polyacrylate latex with nano-silica as the core layer; (3) Preparation of ASA high-colloid powder Add 60g of polyacrylate latex (based on polymer content) to a reactor and heat to 60℃. Then, add 5g of a pre-prepared reducing agent solution to the reactor, followed by the dropwise addition of 30g of styrene monomer, 10g of acrylonitrile monomer, and 0.5g of cumene hydroperoxide initiator over a period of 4 hours. After the addition is complete, heat to 75℃ and maintain the temperature for 1 hour to obtain ASA latex with a three-layer structure. Add a 20 wt% magnesium sulfate flocculant solution to the ASA latex to cause flocculation and demulsification, then centrifuge and wash twice with deionized water to obtain a wet powder of high-polymer ASA. Dry the wet powder of high-polymer ASA in an oven at 65℃ to obtain high-polymer ASA powder. (4) Preparation of ASA resin By extruding and granulating 40g of high-impact ASA powder and 60g of SAN resin (Chimei, grade 138H) using a twin-screw extruder at 220℃, high-impact, heat-resistant, and high-whiteness ASA resin can be obtained.

[0027] Example 3 The preparation method of high-impact, heat-resistant, and high-whiteness ASA resin specifically includes the following steps: (1) Preparation of modified nano-silica particles After purging the polymerization reactor equipped with stirring and ultrasonic functions with nitrogen three times, 3g of nano-sized silica (particle size 7-40 nm, hydrophobic, Shanghai Aladdin Reagent Co., Ltd.) and 80g of organic solvent toluene were added. The ultrasonic (120W power) and stirring (120rpm) were turned on to ensure that the nano-silica was evenly dispersed in the organic solvent toluene. Then, 3g of silane coupling agent KH 172 and 5g of triethylamine were added. After thorough mixing, the reactor temperature was raised to 120℃ and the reaction was carried out for 4 hours. The obtained product was separated using a high-speed centrifuge (10000rpm, 30min). The precipitate separated by centrifugation was repeatedly washed with ethanol, acidified water and deionized water. The product was then dried at 50℃ to obtain silane coupling agent modified silica nanoparticles. (2) Preparation of polyacrylate latex Add 2.5g of modified nano-silica particles to a polymerization reactor, add 60g of deionized water, then add 3g of sodium dodecylbenzenesulfonate emulsifier, turn on the stirrer and ultrasonic device (120W) to ensure that the modified nano-silica is evenly dispersed; then heat the reactor to 65℃, stop the ultrasonication, add 2g of sodium persulfate initiator to the reactor, and then start adding 30g of n-butyl acrylate monomers, 5g of isobutyl acrylate, and 5g of ethyl acrylate, while simultaneously adding 1g of crosslinking agent 1,4-butanediol diacrylate and 2g of grafting agent triallyl isocyanurate. The adding time is controlled at 3h. After the adding is completed, heat the reactor to 85℃ and keep it at that temperature for 2h to obtain polyacrylate latex with nano-silica as the core layer. (3) Preparation of ASA high-colloid powder Add 60g of polyacrylate latex (based on polymer content) to a reactor and heat to 70℃. Then, add 3g of a pre-prepared reducing agent solution to the reactor, followed by the dropwise addition of 25g of styrene monomer, 15g of acrylonitrile monomer, and 0.5g of peroxide initiator cyclohexane peroxide over a period of 3 hours. After the addition is complete, heat to 75℃ and maintain the temperature for 1 hour to obtain ASA latex with a three-layer structure. Add a 20 wt% magnesium sulfate flocculant solution to the ASA latex to cause flocculation and demulsification, then centrifuge and wash twice with deionized water to obtain a wet powder of high-polymer ASA. Dry the wet powder of high-polymer ASA in an oven at 65℃ to obtain high-polymer ASA powder. (4) Preparation of ASA resin By extruding and granulating 40g of high-impact ASA powder and 60g of SAN resin (Chimei, grade 138H) using a twin-screw extruder at 240℃, high-impact, heat-resistant, and high-whiteness ASA resin can be obtained.

[0028] Example 4 The preparation method of high-impact, heat-resistant, and high-whiteness ASA resin specifically includes the following steps: (1) Preparation of modified nano-silica particles After purging the polymerization reactor equipped with stirring and ultrasonic functions with nitrogen three times, 3g of nano-sized silica (particle size 7-40 nm, hydrophobic, Shanghai Aladdin Reagent Co., Ltd.) and 80g of organic solvent toluene were added. The ultrasonic (120W power) and stirring (120rpm) were turned on to ensure that the nano-silica was evenly dispersed in the organic solvent toluene. Then, 3g of silane coupling agent KH 172 and 5g of triethylamine were added. After thorough mixing, the reactor temperature was raised to 120℃ and the reaction was carried out for 4 hours. The obtained product was separated using a high-speed centrifuge (10000rpm, 30min). The precipitate separated by centrifugation was repeatedly washed with ethanol, acidified water and deionized water. The product was then dried at 50℃ to obtain silane coupling agent modified silica nanoparticles. (2) Preparation of polyacrylate latex Add 2.5g of modified nano-silica particles to a polymerization reactor, add 60g of deionized water, and then add 3g of sodium dodecylbenzenesulfonate emulsifier. Turn on the stirrer and ultrasonic device (120W) to ensure that the modified nano-silica is evenly dispersed. Then, heat the reactor to 60℃, stop the ultrasonication, add 0.5g of ammonium persulfate initiator to the reactor, and then start adding 20g of butyl acrylate monomers and 20g of isooctyl acrylate. At the same time, add 1g of crosslinking agent 1,6-hexanediol diethylene glycol acrylate and 5g of grafting agent triallyl isocyanurate. Control the addition time to 3h. After the addition is completed, heat the reactor to 80℃ and keep it at that temperature for 1h to obtain polyacrylate latex with nano-silica as the core layer. (3) Preparation of ASA high-colloid powder Add 60g of polyacrylate latex (based on polymer content) to a reactor and heat to 70℃. Then, add 5g of a pre-prepared reducing agent solution to the reactor, followed by dropwise addition of 25g of styrene monomer, 15g of acrylonitrile monomer, and 0.5g of hydrogen peroxide tert-butanol peroxide initiator over a period of 3 hours. After the addition is complete, heat to 75℃ and maintain the temperature for 1 hour to obtain ASA latex with a three-layer structure. Add a 20 wt% magnesium sulfate flocculant solution to the ASA latex to cause flocculation and demulsification, then centrifuge and wash twice with deionized water to obtain a wet powder of high-polymer ASA. Dry the wet powder of high-polymer ASA in an oven at 65℃ to obtain high-polymer ASA powder. (4) Preparation of ASA resin By extruding and granulating 40g of high-impact ASA powder and 60g of SAN resin (Chimei, grade 138H) using a twin-screw extruder at 240℃, high-impact, heat-resistant, and high-whiteness ASA resin can be obtained.

[0029] Comparative Example 1 The only difference from Example 1 is that the nanoscale silica used in Comparative Example 1 is large-particle silica with an average particle size of 100-200 nm.

[0030] Comparative Example 2 The only difference from Example 1 is that the nano-sized silica used in Comparative Example 2 is used directly without modification by a coupling agent.

[0031] Comparative Example 3 The difference from Example 1 is that the polyacrylate latex is prepared using traditional emulsion polymerization technology, without using nano-sized silica as a toughening agent in the core structure. Specifically, the process includes the following steps: (1) Preparation of polyacrylate latex After purging the reactor twice with nitrogen, add 60g of deionized water, then add 1g of sodium dodecyl sulfate emulsifier, and heat the reactor to 60°C. Add 0.2g of potassium persulfate initiator to the reactor, and then start adding 40g of butyl acrylate monomer, 1g of ethylene glycol dimethacrylate crosslinking agent, and 1g of allyl methacrylate grafting agent. Control the adding time to 2 hours. After the adding is completed, heat the reactor to 80°C and keep it at that temperature for 1 hour to obtain polyacrylate latex. (2) Preparation of ASA high-colloid powder Add 60g of polyacrylate latex (based on polymer content) to a reactor and heat to 40℃. Then, add 1g of a pre-prepared reducing agent solution to the reactor, followed by the dropwise addition of 30g of styrene monomer, 10g of acrylonitrile monomer, and 0.5g of diisopropylbenzene hydrogen peroxide per drop, with the dropwise addition time controlled at 1h. After the dropwise addition is complete, heat to 75℃ and maintain the temperature for 1h to obtain ASA latex. Add a 5 wt% calcium chloride flocculant solution to the ASA latex to cause flocculation and demulsification, then centrifuge and wash twice with deionized water to obtain a wet powder of high-polymer ASA. Dry the wet powder of high-polymer ASA in an oven at 65℃ to obtain high-polymer ASA powder. (3) Preparation of ASA resin ASA resin can be obtained by extruding 40g of high-polymer ASA powder and 60g of SAN resin (Chimei, grade 138H) using a twin-screw extruder at 220°C.

[0032] Performance testing The ASA resins prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to the following tests: ① Prepare 3.2mm notched specimens according to ASTM D256 standard (Standard Test Method for Impact Strength of Plastic Cantilever Beams) and test their impact strength (KJ / m).2 ); ② Prepare standard tensile specimens according to ASTM D638 (Standard Test Method for Tensile Properties of Plastics) and test their tensile strength (MPa). ③ Prepare standard heat distortion specimens according to ASTM D648 standard (Standard for determination of heat distortion temperature (HDT) of plastics) and test their heat distortion temperature (°C). ④ Prepare Vicat softening point test strips according to ASTM 1525 standard (Standard Method for Determination of Vicat Softening Temperature of Plastics) and test their Vicat softening point (°C); ⑤ Prepare whiteness plate samples according to GB / T13025.2 (General Test Method for Determination of Whiteness in Salt Industry) and test their whiteness.

[0033] The test results are shown in Table 1.

[0034] Table 1. Performance test results of ASA resins in Examples 1-4 and Comparative Examples 1-3.

[0035] As can be seen from the test data in Table 1, compared with the traditional process in Example 3, the impact strength, heat distortion temperature, Vicat softening point, and whiteness of Examples 1-4 are significantly improved due to the addition of modified nano-sized silica. In Comparative Example 1, the impact strength was not improved because the silica particles used were too large, but its heat distortion temperature, Vicat softening point, and whiteness increased significantly. In Comparative Example 2, because the silica added was not modified with a coupling agent, the performance parameters are similar to those of the ASA resin prepared by the traditional process in Comparative Example 3.

[0036] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high impact, heat resistant grade, high whiteness ASA resin characterized in that, ASA high glue powder 40 parts and SAN resin 60 parts; The ASA high glue powder comprises raw materials in the following weight parts: polyacrylate latex 60 parts, reducing agent solution 1 part, styrene monomer 30 parts, acrylonitrile monomer 10 parts and peroxide initiator 0.5 parts; The polyacrylate latex comprises raw materials in the following weight parts: modified nano-silica particles 1 part, deionized water 60 parts, emulsifier 1 part, initiator 0.2 parts, acrylate monomer 40 parts, crosslinking agent 1 part and grafting agent 1 part; The modified nano-silica particles comprise raw materials in the following weight parts: nano-silica 5 parts, organic solvent 80 parts, silane coupling agent 5 parts and organic amine 5 parts.

2. The high-impact, heat-resistant, high-whiteness ASA resin according to claim 1, characterized in that, ASA high glue powder 40 parts and SAN resin 60 parts; The ASA high glue powder comprises raw materials in the following weight parts: polyacrylate latex 60 parts, reducing agent solution 1 part, styrene monomer 30 parts, acrylonitrile monomer 10 parts and peroxide initiator 0.5 parts; The polyacrylate latex comprises raw materials in the following weight parts: modified nano-silica particles 1 part, deionized water 60 parts, emulsifier 1 part, initiator 0.2 parts, acrylate monomer 40 parts, crosslinking agent 1 part and grafting agent 1 part; The modified nano-silica particles comprise raw materials in the following weight parts: nano-silica 5 parts, organic solvent 80 parts, silane coupling agent 5 parts and organic amine 5 parts.

3. The high-impact, heat-resistant, high-whiteness ASA resin according to claim 1, characterized in that, ASA high glue powder 40 parts and SAN resin 60 parts; The ASA high glue powder comprises raw materials in the following weight parts: polyacrylate latex 60 parts, reducing agent solution 1 part, styrene monomer 30 parts, acrylonitrile monomer 10 parts and peroxide initiator 0.5 parts; The polyacrylate latex comprises raw materials in the following weight parts: modified nano-silica particles 1 part, deionized water 60 parts, emulsifier 1 part, initiator 0.2 parts, acrylate monomer 40 parts, crosslinking agent 1 part and grafting agent 1 part; The modified nano-silica particles comprise raw materials in the following weight parts: nano-silica 5 parts, organic solvent 80 parts, silane coupling agent 5 parts and organic amine 5 parts.

4. The high-impact, heat-resistant, high-whiteness ASA resin according to claim 1, characterized in that, ASA high glue powder 40 parts and SAN resin 60 parts; The ASA high glue powder comprises raw materials in the following weight parts: polyacrylate latex 60 parts, reducing agent solution 1 part, styrene monomer 30 parts, acrylonitrile monomer 10 parts and peroxide initiator 0.5 parts; The polyacrylate latex comprises raw materials in the following weight parts: modified nano-silica particles 1 part, deionized water 60 parts, emulsifier 1 part, initiator 0.2 parts, acrylate monomer 40 parts, crosslinking agent 1 part and grafting agent 1 part; The modified nano-silica particles comprise raw materials in the following weight parts: nano-silica 5 parts, organic solvent 80 parts, silane coupling agent 5 parts and organic amine 5 parts.

5. The high-impact, heat-resistant, high-whiteness ASA resin according to claim 1, characterized in that, ASA high glue powder 40 parts and SAN resin 60 parts; The ASA high glue powder comprises raw materials in the following weight parts: polyacrylate latex 60 parts, reducing agent solution 1 part, styrene monomer 30 parts, acrylonitrile monomer 10 parts and peroxide initiator 0.5 parts; The polyacrylate latex comprises raw materials in the following weight parts: modified nano-silica particles 1 part, deionized water 60 parts, emulsifier 1 part, initiator 0.2 parts, acrylate monomer 40 parts, crosslinking agent 1 part and grafting agent 1 part; The modified nano-silica particles comprise raw materials in the following weight parts: nano-silica 5 parts, organic solvent 80 parts, silane coupling agent 5 parts and organic amine 5 parts. ASA high glue powder 40 parts and SAN resin 60 parts; The ASA high glue powder comprises raw materials in the following weight parts: polyacrylate latex 60 parts, reducing agent solution 1 part, styrene monomer 30 parts, acrylonitrile monomer 10 parts and peroxide initiator 0.5 parts; The polyacrylate latex comprises raw materials in the following weight parts: modified nano-silica particles 1 part, deionized water 60 parts, emulsifier 1 part, initiator 0.2 parts, acrylate monomer 40 parts, crosslinking agent 1 part and grafting agent 1 part; The modified nano-silica particles comprise raw materials in the following weight parts: nano-silica 5 parts, organic solvent 80 parts, silane coupling agent 5 parts and organic amine 5 parts. The ASA high glue powder comprises the following raw materials by weight: 60 parts of polyacrylate latex, 5 parts of reducing agent solution, 25 parts of styrene monomer, 15 parts of acrylonitrile monomer and 0.5 parts of peroxide initiator; The polyacrylate latex comprises the following raw materials by weight: 2.5 parts of modified nano-silica particles, 60 parts of deionized water, 3 parts of emulsifier, 0.5 parts of initiator, 40 parts of acrylate monomer, 1 part of crosslinking agent and 5 parts of grafting agent; The modified nano-silica particles comprise the following raw materials by weight: 3 parts of nano-silica, 80 parts of organic solvent, 3 parts of silane coupling agent and 5 parts of organic amine.

6. A high-impact, heat-resistant grade, high-whiteness ASA resin according to any one of claims 1 to 5, characterized in that, The nano-silica has a size of 5-100 nm; The organic solvent is at least one of toluene, ethylbenzene and xylene; The silane coupling agent is at least one of vinyl tri(2-methoxyethoxy) silane and γ-methacryloyloxypropyl trimethoxysilane; The organic amine is at least one of diethylamine and triethylamine.

7. A high-impact, heat-resistant grade, high-whiteness ASA resin according to any one of claims 1 to 5, characterized in that, The emulsifier is at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate and sodium dodecyl benzene sulfonate; The initiator is at least one of potassium persulfate, sodium persulfate and ammonium persulfate; The acrylate monomer is at least one of n-butyl acrylate, isobutyl acrylate, iso-octyl acrylate and ethyl acrylate; The crosslinking agent is at least one of ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol diacrylate and 1,4-butanediol diacrylate; The grafting agent is one of allyl methacrylate, triallyl cyanurate and triallyl isocyanurate.

8. A high-impact, heat-resistant grade, high-whiteness ASA resin according to any one of claims 1-5, characterized in that, The reducing agent solution is a solution prepared from EDTA disodium salt, ferrous sulfate, sodium thiosulfate and deionized water according to a mass ratio of 0.02:0.01:0.1:10; The peroxide initiator is at least one of cumene hydroperoxide, di-cumene hydroperoxide, cyclohexane hydroperoxide, tert-butyl hydroperoxide and di-tert-butyl hydroperoxide.

9. A process for the preparation of a high impact, heat resistant grade, high whiteness ASA resin, characterized in that, Specifically comprising the following steps: (1) weighing each raw material The high-impact, heat-resistant and high-whiteness ASA resin according to any one of claims 1-8 is weighed; (2) preparation of modified nano-silica particles Disperse nano-silica and organic solvent in organic solvent, add silane coupling agent and organic amine, heat and react, separate the precipitate, wash and dry to obtain modified nano-silica particles; (3) preparation of polyacrylate latex Disperse modified nano-silica particles in deionized water and emulsifier, heat, add initiator, then add acrylate monomer, crosslinking agent and grafting agent, heat and react to obtain polyacrylate latex; (4) preparation of ASA high glue powder Heat polyacrylate latex, add reducing agent solution, styrene monomer, acrylonitrile monomer 5-10 parts and peroxide initiator, heat and react, flocculate and demulsify, centrifugal separation, wash and dry to obtain ASA high glue powder; (5) preparation of ASA resin Extrude and granulate ASA high glue powder and SAN resin to obtain the high-impact, heat-resistant and high-whiteness ASA resin.

10. The process for the preparation of a high impact, heat resistant grade, high whiteness ASA resin according to claim 9, characterized in that, In step (2), the temperature of the temperature-increasing reaction is 100-130℃, and the time is 3-5h; the reagent for washing is ethanol, acidified water and deionized water; the temperature of drying is 40-60℃; In step (3), the temperature is increased to 60-75℃; the temperature of the temperature-increasing reaction is 80-85℃, and the time is 1-2h; In step (4), the temperature is increased to 40-70℃; the temperature of the temperature-increasing reaction is 75-85℃, and the time is 1-2h; the reagent for flocculation demulsification is a 5-20 wt% flocculant solution; the reagent for washing is deionized water; In step (5), the equipment for extrusion granulation is a double-screw extruder, and the temperature is 220-240℃.

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