CN102604006A - Preparation method for acidic silica sol in-situ modified acrylate emulsion - Google Patents

Abstract

A preparation method for acidic silica sol in-situ modified acrylate emulsion includes the steps: firstly, diluting acidic silica sol with deionized water prior to adding small molecular alcohol, and then adding organo-siloxane with mixing to obtain modified acidic silica sol; then, utilizing the modified acidic silica sol, emulsifier, nuclear-layer monomers, deionized water and sodium bicarbonate to prepare seed pre-emulsion by means of pre-emulsification, adding the seed pre-emulsion into a reactor, heating up and adding initiator to initiate polymerization so that seed emulsion is prepared; and finally, adding emulsifier, shell monomers, initiator and deionized water into the reactor to prepare pre-emulsion by means of pre-emulsification, adding the pre-emulsion into the seed emulsion, replenishing initiator to hold, filtering after cooling to the normal temperature, and adjusting a pH (potential of hydrogen) value so that the modified acrylate emulsion is prepared. By the aid of the method, secondary dispersion of nano silica is avoided, stability of the emulsion is enhanced, and hardness, resistance to ultraviolet ageing and resistance to high temperature of an emulsion coating film are enhanced.

Description

A kind of method of acidic silica sol in situ modified acrylate emulsion

technical field

The invention relates to a method for modifying an acrylate emulsion in situ with an acidic silica sol, in particular to a method for preparing an aqueous heat-crosslinkable acrylate emulsion synthesized by using nano silicon dioxide through an in-situ/seed emulsion polymerization process.

Background technique

Traditional physical blending is a type of composite material obtained by directly dispersing and mixing nano-silica in the emulsion. Due to the poor compatibility between the organic phase and the inorganic phase, it is difficult to obtain nano-silica particles in the organism. Evenly dispersed, there are also problems such as poor interface affinity between acrylate and nanomaterial particles and poor storage stability. In order to make silica and acrylic resin have good compatibility in later technologies, the surface modification of nano-silica is usually carried out first, and the esterification or condensation reaction of its hydroxyl functional group is generally used. For example, a composite emulsion of silica sol and acrylate is characterized in that the inorganic phase of nano-silica is dispersed in the composite emulsion, wherein the ratio of nano-silica to the mass of acrylate monomer is 0.1%-5%, and the used Nano-silica is surface-treated, and the used organic silicon content of nano-silica modification has also had a great impact on the stability and mechanical strength of the emulsion. For details, see the publication number CN1654533 "Nano-silica/ Acrylate composite emulsion and its preparation method". The publication number is CN102030873A "A Preparation Method of Nano-Silicon Dioxide/Polyacrylate Composite Emulsion", which introduces the modification method of nano-silicon dioxide in detail. Coupling agent and monomer are obtained by reacting in an acidic aqueous solution adjusted with hydrochloric acid for 8-24 hours, but the method has the problem of "secondary agglomeration" of nano-silica, which affects the normal progress of emulsion polymerization and the stability of the emulsion . What is used more is in-situ emulsion polymerization. For example, the publication number is CN 1908022 "A Preparation Method for Inorganic Nanoparticle Modified Self-crosslinking Acrylate Emulsion at Room Temperature", which describes the preparation of orthosilicate in ethanol. After the nano-silica is prepared, it is modified with silicone, and then dispersed in the acrylate monomer for in-situ emulsion polymerization to obtain a nano-silica-modified acrylate emulsion. The method of in-situ emulsion polymerization can The uniform dispersion of nano-silica in the polymer improves the physical and mechanical properties of the polymer to a certain extent, but the existing modification process of nano-silica is complicated, and the modified nano-silica is used for polymerization It is also easy to "secondary agglomeration", which affects the stability of the emulsion and the normal progress of the polymerization process. The publication number is CN1654489's "Preparation Method of Nano-SiO2-Acrylic Ester Composite Emulsion", which describes that nano-SiO2 is dispersed in benzene derivatives, stirred and modified with silane coupling agent, and after centrifugation, use Rinse with acetone, organic solvents are used in the modification process, which is not conducive to environmental protection, and the operation is also complicated. Patent CN101412783 "Preparation Method of Acrylate Copolymer Emulsion for Pressure-sensitive Adhesives" invented a seed emulsion with only nano-silica and no other polymerizable monomers. The body was polymerized, and a silica-acrylate copolymer emulsion was synthesized. It can be speculated that the silicon hydroxyl group in the silica interacted with the active group carboxyl group of the diisooctyl sodium sulfonate emulsifier to make the silica Silicon is modified, otherwise, due to the high specific surface area of silica, silica will be highly self-polymerized, the polymerization reaction is difficult to carry out, and the requirements for emulsifiers are relatively high.

Contents of the invention

The technical problem to be solved in the present invention is to use acidic silica sol with uniform dispersion and small particle size, and to graft and modify nano-silica in an environmentally friendly manner under a simple process flow, and use in-situ/seed emulsion polymerization The method synthesized the acrylate strawberry or pomegranate latex particles coated with nano-silica, and added active monomers that can produce thermal crosslinking during the polymerization process, the purpose is to provide an acidic silica sol collagen site Preparation method of modified acrylate emulsion.

Based on above-mentioned purpose, be to provide a kind of method of acidic silica sol position modification acrylate emulsion, carry out according to the following steps during its method:

(1) Modification of silica sol

At 45-55°C, take 100 parts of acidic silica sol, dilute with 0-80 parts of deionized water, add 5-25 parts of small molecule alcohol, and finally add 1.0-1.5 parts of organosiloxane and stir for 3 hours to obtain the modified Sexual silica sol;

(2) Synthesis of acrylic emulsion

(1) Seed emulsion polymerization stage: Take 40-85 parts of modified silica sol, 2-4 parts of emulsifier, 16-24 parts of core layer monomer, 30-65 parts of deionized water and 0.8 parts of Sodium bicarbonate, pre-emulsified for 1 hour to make seed pre-emulsion, then put it into the reaction kettle, raise the temperature to 70-75°C, then add 0.1-0.3 parts of initiator to initiate polymerization, after half an hour of reaction, heat up to 80-85 ℃ and keep warm for half an hour;

(2) Emulsion polymerization stage: add 1 to 3 parts of emulsifier, 60 to 80 parts of shell monomer, 0.4 to 0.6 parts of initiator and 30 to 50 parts of deionized water into the reactor, and pre-emulsify for 1 hour to make a pre-emulsion , add it to the seed emulsion within 3 hours, add 0.0004 parts of the total monomer amount of the initiator and keep it warm for 1 hour, drop to normal temperature and filter the material, and finally adjust the pH to 8-9 to prepare a modified acrylate emulsion .

In the above technical scheme, the emulsifier is CO-436 or CO-458: CO-897 or CO-630 is compounded and used in a ratio of 1 : 1.5 to 1 : 3.5; The body is butyl acrylate and methyl methacrylate; the shell monomer is one or more of methyl methacrylate, butyl acrylate, acrylic acid, methacrylic acid, and hydroxyethyl acrylate in any proportion Mixing, wherein the active group-containing monomer hydroxyethyl acrylate accounts for 0.03 to 0.2 parts of the total monomer amount; the organosiloxane is γ-(methacryloyloxy)propyltrimethoxysilane: KH- 570. γ-aminopropyltriethoxysilane: KH-550 and γ-glycidyl etheroxypropyltrimethoxysilane: one or more of KH-560 mixed in any proportion, the amount of organosiloxane Accounting for 0.04-0.06 parts of the solid content of nano-silica in the silica sol; the initiator is one of ammonium persulfate, potassium persulfate-sodium bisulfite, and the dosage accounts for 0.003-0.012 parts of the total monomer mass ; The small molecule alcohol is one or more of ethanol, propanol and ethylene glycol; the acidic silica sol has a particle size of 10-20nm and a solid content of 25%-26%.

The advantages and positive effects brought by the technical solution of the present invention are that the "secondary dispersion" of nano silicon dioxide is avoided, which is beneficial to the smooth progress of emulsion synthesis, improves the stability of the emulsion, and also improves the hardness of the emulsion coating film , Water resistance, oil resistance, UV aging resistance and high temperature resistance.

Detailed ways

The specific embodiment of the present invention is described as follows:

The present invention simplifies the flow process of organosiloxane grafting modification of nano-silica by ultrasonic dispersion, modification, purification and redispersion in the prior art using tetraethyl orthosilicate as the starting material, and avoids intermediate The process uses organic solvents other than small molecule alcohols, which is more environmentally friendly. Using silica sol as the starting material, an excellent process for modifying nano-silica suitable for this emulsion polymerization has been found. First, with the help of acidic silica sol The dispersion is uniform and stable, and it is also in a stable state after modification. It avoids the secondary agglomeration caused by multiple dispersions in the background technology. At the same time, it is further modified and dispersed after being mixed with monomers and emulsifiers, so that The stable progress of the emulsion polymerization is ensured. Secondly, due to the small particle size of the silica sol, the modified nano-silica can easily enter the micelles. Through in-situ emulsion polymerization, a pomegranate-type or Strawberry-shaped spherical colloidal particles, the addition of monomers containing active groups in the shell makes the emulsion cross-linked at high temperature to form a network structure, which improves water resistance and hardness. The appropriate ratio of core-shell monomers makes the particle size distribution of the synthesized emulsion Narrow and at the nanometer level, thus ensuring the transparency and high gloss of the coating film, an effective process is proposed to solve the problems of low hardness and poor wear resistance of acrylate emulsion.

The present invention focuses on effectively utilizing the rigidity and hardness of inorganic nano-silica particles combined with the toughness of polymer materials to obtain an acrylate emulsion with good mechanical properties through chemical modification and modification. The addition of nano-silica not only improves Improve the tensile strength and elongation at break of the coating film, enhance the wear resistance, pollution resistance, water resistance, and also improve the anti-ultraviolet aging ability.

After the nano silicon dioxide in the silica sol of the present invention is modified by organosilicon grafting, in the emulsification stage, the surface of the nano silicon dioxide is further modified by emulsifiers and monomers, so that the polymerization can proceed smoothly. The modification method is also more environmentally friendly. Add a certain amount of acidic silica sol (commercially available) to a mixed solution of a certain volume of deionized water and small molecule alcohol, then add organosiloxane and stir at a certain temperature for modification. This method not only simplifies the process of directly modifying nano-silica with ethyl silicate, but also avoids the re-dispersion of modified nano-silica, thereby reducing the probability of "secondary agglomeration" of nano-silica. Improved process flow.

The active groups of the acrylate emulsion of the present invention are carboxyl and hydroxyl groups from the shell of latex particles. On the one hand, the latex particles themselves are thermally crosslinked, and on the other hand, they can be thermally crosslinked with amino resins to form a three-dimensional network structure. Further improve the water and oil resistance and hardness of the coating, and effectively reduce the pollution of organic volatiles to the environment.

Among them, the stability of silica sol depends on the interaction of nanoparticles and the steric hindrance effect provided by surfactants, acids or bases. Therefore, when the pH and temperature of the sol change, the original balance will be broken to cause gelation. or reunion. Experiments have shown that the effect of acidic silica sol modified by silane coupling agent is more significant, because the activity of silicon hydroxyl in acidic environment is stronger than that of alkaline silica sol, using the acidic environment of acidic silica sol itself, the Its modification eliminates the influence of the agglomeration of nano-silica due to the change of acidity and alkalinity, and the modified silica sol is opposite to the charge of the anionic emulsifier when it is pre-emulsified, and part of the emulsifier will also be charged by electrostatic action. It is partially coated and modified, thereby improving the degree of lipophilic modification of nano-silica; higher temperature will cause fierce collisions between nano-silica, resulting in agglomeration, and the degree of agglomeration is affected by the grafting of nano-silica. Influenced by the rate, if the amount of silicone is too small, the grafting rate is less and more agglomerated. With the increase of the amount of silicone, the grafting rate on the surface of nano-silica particles increases, the self-agglomeration decreases, the particle size decreases, and the stability Good resistance, if it continues to increase, it will lead to more agglomeration and affect dispersion. The modification temperature of acidic silica sol is 45 ° C ~ 55 ° C, and the amount of organosiloxane is the solid content of nano-silica in acidic silica sol. 0.04 to 0.06 parts.

The emulsion used in the present invention is to coat nano-silica in acrylate latex particles through in-situ emulsion polymerization. Adding nano-silica can not only double the tensile strength and elongation at break of the coating film, but also silicon dioxide The addition of sol takes advantage of its polyhydric properties to enhance wear resistance, pollution resistance and water resistance, as well as excellent anti-ultraviolet aging ability. However, when nano-silica is directly added as a filler to the acrylate emulsion for physical mixing, it is difficult to disperse and the stability after mixing is not good. The purpose of nano-silica modification is to graft the hydrophilic silanol on the surface of nano-silica through esterification, condensation or electrostatic interaction with other compounds containing lipophilic groups, so that it can be changed from hydrophilic It becomes lipophilic and is easier to be covered by emulsifiers. The grafting rate of hydroxyl groups on the surface of nano-silica is limited. , the amount of silicone added should not be too small, otherwise the grafting rate will not be complete, and the gel rate will increase after in-situ emulsion polymerization, while too much will cause self-polymerization due to the presence of rich silicone, making the emulsion stable. Decreased stability and water resistance. the

The organosiloxanes used in the present invention are: γ-(methacryloyloxy)propyl trimethoxysilane: KH-570, γ-aminopropyl triethoxysilane: KH-550 and γ-glycidyl ether Oxypropyltrimethoxysilane: One or more of KH-560 are mixed in any proportion.

The small molecule alcohols used in the present invention are: one or more of ethanol, propanol and ethylene glycol.

The initiation efficiency of the initiator used in the present invention is related to the concentration of the initiator. If the concentration of the initiator is too large, the polymerization rate is too fast, or even implosion. If the concentration of the initiator is too low, the polymerization rate is too slow, the polymerization is incomplete, the conversion rate is low, and the polymerization During the process, nitrogen gas should also be introduced for protection to prevent free radicals from being consumed by oxygen. The initiator is one of ammonium persulfate and potassium persulfate-sodium bisulfite, and the dosage is 0.003-0.012 parts of the total amount of monomers. the

The anionic emulsifier used in the present invention stabilizes particle dispersion with the effect of electric double layer and shielding stabilization, and the nonionic emulsifier then increases the stability of the emulsion with shielding stabilization; anionic emulsifier and nonionic emulsifier compound The advantage of use is that the charge stability of anionic emulsifier and the steric hindrance of nonionic emulsifier can produce a coordination effect and improve the stability of emulsion particles. In the present invention, anionic and nonionic emulsifiers are used in combination during the polymerization process. In this way, the stability and water resistance of the emulsion can be significantly improved under the premise of ensuring the emulsification effect. The emulsifier is CO-436 or CO-458: CO-897 or CO-630 in parts ratio 1 : 1.5～1 : The ratio of 3.5 is compounded and used.

A kind of preparation method of acidic silica sol situ modified acrylate emulsion of the present invention, the method is carried out according to the following steps:

(1) Modification of silica sol

At 45-55°C, first take 100 parts of acidic silica sol, dilute with 0-80 parts of deionized water, then add 5-25 parts of small molecule alcohol, and finally add 1.0-1.5 parts of organosiloxane and stir for 3 hours. Obtain modified silica sol;

(2) Synthesis of acrylic emulsion

(1) Seed emulsion polymerization stage: Take 40-85 parts of modified silica sol, 2-4 parts of emulsifier, 16-24 parts of core layer monomer, 30-65 parts of deionized water and 0.8 parts of Sodium bicarbonate, pre-emulsified for 1 hour to make a seed pre-emulsion, and then put it into the reactor. The temperature of the reactor is 70-75°C, and then add 0.1-0.3 parts of initiator to initiate polymerization. After half an hour of reaction, the temperature is raised to 80～85℃ and keep warm for half an hour;

(2) Emulsion polymerization stage: add 1 to 3 parts of emulsifier, 60 to 80 parts of shell monomer, 0.4 to 0.6 parts of initiator and 30 to 50 parts of deionized water into the reactor, pre-emulsify for 1 hour, and make a pre-emulsified Emulsion, add it to the seed emulsion within 3 hours, add 0.0004 parts of the total monomer amount of initiator and keep it warm for 1 hour, drop to normal temperature and filter the material, and finally adjust the pH to 8-9 to obtain modified acrylic acid Ester emulsion.

The core layer monomer of the present invention is butyl acrylate and methyl methacrylate, and the shell layer monomer is one or more of methyl methacrylate, butyl acrylate, acrylic acid, methacrylic acid, and hydroxyethyl acrylate. Mixing in any proportion, wherein the active group-containing monomer hydroxyethyl acrylate accounts for 0.03-0.2 parts of the total monomer parts.

The specific embodiment of the present invention is further described in detail below by embodiment:

Embodiment one

Implement the preparation method of a kind of acidic silica sol situ modified acrylate emulsion provided by the present invention, carry out as follows:

The first step is silica sol modification. Add 16kg of deionized water and 20kg of acidic silica sol with a solid content of 25% into a 50L reactor, mix well, then add 4kg of ethanol and mix well, then slowly add 0.3kg KH-560 to the reactor, 50℃ The mixture was stirred and reacted for 3 hours to obtain a modified silica sol.

The second step is the synthesis of seed emulsion. In a reaction kettle with a volume of 100L, add 0.167kg of anionic emulsifier CO-436 and 0.334kg of nonionic emulsifier CO-897 into 4.5kg of deionized water, then add 14kg of modified silica sol and stir at 30°C for 15min, then Add 2.4kg of methyl methacrylate (MMA) and 0.8kg of butyl acrylate (BA) to pre-emulsify for half an hour, adjust the pH to 7-8 with ammonia water, add 0.16kg of NaHCO ₃ and 2kg of deionized water to prepare the buffer , continue to emulsify for half an hour, add the pre-emulsion into a 100 L reactor, raise the temperature to 75°C under the protection of nitrogen, then add an aqueous solution prepared by dissolving 0.023 kg of ammonium persulfate in 1 kg of deionized water into the reactor, and react After half an hour, the temperature was raised to 83° C. and kept warm for half an hour to obtain a seed emulsion.

The third step is emulsion synthesis. 6.3㎏ methyl methacrylate (MMA), 4.1㎏ butyl acrylate (BA), 1.4㎏ hydroxyethyl acrylate (HEA), 0.7㎏ methacrylic acid (MAA): methacrylic acid is first deionized with 1 kg After diluting with water, adjust the pH value to 7~8 with ammonia water or AMP-95, add 0.082㎏ CO-436, 0.164㎏CO-897, and 0.1㎏ ammonium persulfate into 8kg deionized water and pre-emulsify for 1 hour to obtain a pre-emulsion. Add the pre-emulsion to the above seed emulsion within 3 hours, the temperature of the seed emulsion is 83°C, raise the temperature to 85°C, add an initiator with a total monomer amount of 0.00628 kg, keep it warm for one hour, cool and filter the material, and adjust the pH value to 8 ~9 to obtain an emulsion, the viscosity of this emulsion is 14s, the blue light is sufficient, the coating film hardness is 4H, and the water absorption rate is 3%.

Embodiment two

Compared with Example 1, the amount of emulsifier and initiator in this embodiment is changed. The amounts of CO-436 and CO-897 in the seed emulsion polymerization stage are 0.16 kg and 0.56 kg respectively, and the amount of initiator is 0.02 kg. The amount of CO-436 and CO-897 in the polymerization stage is 0.12kg and 0.42kg respectively, and the initiator is 0.072kg.

Embodiment Three

The modification methods of silica sol are different:

Modification of silica sol 1. Add 0kg of deionized water and 20kg of acidic silica sol with a solid content of 25% into a reactor with a volume of 50L, mix well, then add 4kg of ethanol and mix well, then slowly add 0.3kg of KH-550 to the reactor, 50°C The mixture was stirred and reacted for 3 hours to obtain a modified silica sol.

Modification of silica sol 2. Add 16kg of deionized water and 20kg of acidic silica sol with a solid content of 25% into a 50L reactor, mix well, then add 4kg of ethanol and mix well, then slowly add 0.25kg of KH-560 to the reactor at 50°C The mixture was stirred and reacted for 3 hours to obtain a modified silica sol.

Modification of silica sol 3. Add 16kg of deionized water and 20kg of acidic silica sol with a solid content of 25% into a 50L reactor, mix well, then add 5kg of ethanol and mix well, then slowly add 0.3kg of KH-560 to the reactor at 45°C The mixture was stirred and reacted for 3 hours to obtain a modified silica sol.

Modification of silica sol4. Add 16kg of deionized water and 20kg of acidic silica sol with a solid content of 25% into a 50L reactor, mix well, then add 1kg of ethanol and mix well, then slowly add 0.2kg of KH-560 to the reactor at 55°C The mixture was stirred and reacted for 3 hours to obtain a modified silica sol.

Modification of silica sol 5. Add 16kg of deionized water and 20kg of acidic silica sol with a solid content of 25% into a 50L reactor, mix well, then add 3kg of ethanol and mix well, then slowly add 0.2kg of KH-570 to the reactor at 55°C The mixture was stirred and reacted for 3 hours to obtain a modified silica sol.

All the other are the same as embodiment one.

Embodiment Four

Compared with Example 1, this example uses an equal amount of organic silicon KH-570 or A-171, KH-550 instead of KH-560 to modify the silica sol, and the rest are the same as Example 1. The viscosity of the synthesized emulsion is More than 35s, the solid content is low, the gel rate is also increased, and the prepared coating film is basically flat.

Embodiment five

Compared with Example 1, this example is that in the stage of emulsion polymerization, the consumption of hydroxyethyl acrylate is increased to 3.4 kg, and the rest is the same as Example 1. The gel rate of the obtained emulsion is increased, and the water absorption rate is 4.5%.

Embodiment six

Compared with Example 1, the initiator used in this example is potassium persulfate-sodium bisulfite (1:1) redox initiator, the amount used in the seed emulsion polymerization stage is 0.05 kg, and the polymerization temperature is 70 °C. The temperature is 75°C, the amount of initiator used in the emulsion polymerization stage is 0.18 kg, the polymerization temperature is 80°C, the holding temperature is 83°C, and the rest are the same as in Example 1.

Embodiment seven

Compared with Example 1, this example is different in that CO-897 is replaced by CO-630 and CO-436 is replaced by CO-458. In the seed emulsion polymerization stage, the amounts of CO-458 and CO-630 are respectively Be 0.144㎏ and 0.216㎏, the amount of initiator becomes 0.054㎏, the emulsion polymerization stage, the amount of CO-458 and CO-630 is respectively 0.072㎏ and 0.108㎏, the amount of initiator becomes 0.108kg, all the other are the same as embodiment one, The gel ratio of the emulsion increases and the calcium ion stability decreases.

Embodiment Eight

Compared with Example 1 in this example, only 6kg of methyl methacrylate (MMA), 4kg of butyl acrylate (BA), and 2.2kg of hydroxyethyl acrylate (HEA) were used in the emulsion polymerization stage. Example 1, the resulting emulsion is blue enough, and the viscosity is 13 seconds with Tu-4 cup.

Embodiment nine

In this example, compared with Example 1, the amount of modified silica sol added in the seed emulsion polymerization stage was reduced to 7.2 kg, and 4.5 kg of deionized water was added, and the performance of the obtained emulsion was slightly improved, and the rest were the same as in Example 1.

Embodiment ten

Compared with Example 1, this example uses an equal amount of acrylic acid (AA) instead of methacrylic acid (MAA), and the rest is the same as Example 1, and the gel ratio of the emulsion increases slightly.

Embodiment Eleven

Compared with Example 1, the amount of MMA and BA in the seed emulsion polymerization stage increased to 3.24 kg and 1.05 kg, respectively, the amount of MMA and BA in the emulsion polymerization stage increased to 6.66 kg and 4.5 kg, and the amount of HEA increased to 1.8 ㎏, acrylic acid consumption is constant, and all the other are with embodiment one, and the particle diameter of emulsion increases.

Embodiment 12

Compared with embodiment eleven, the consumption of HEA in this embodiment is reduced to 0.5 kg, and all the other are the same as embodiment eleven, and the oil resistance and water resistance of the emulsion become worse.

Claims (8)

1. the method for the in-situ modified acrylic ester emulsion of acidic silicasol, this method follows these steps to carry out:

(1) silica sol modified

Under 45～55 ℃, get 100 parts of acidic silicasols, after 0～80 part of deionized water dilution, add 5～25 parts of small molecular alcohols, add 1.0～1.5 parts of organo-siloxanes at last and stirred 3 hours, obtain modified silicasol;

(2) ACRYLIC EMULSION is synthetic

(1) the seeded emulsion polymerization stage: get 40～85 parts of modified silicasols, 2～4 parts of emulsifying agents, 16～24 parts of nuclear layer monomer, 30～65 parts of deionized waters and 0.8 part of sodium hydrogencarbonate in the above-mentioned steps (); Emulsification is 1 hour in advance, processes the seed pre-emulsion, then it is added reaction kettle; Be warming up to 70～75 ℃; Add 0.1～0.3 part of initiator initiated polymerization again, after reaction half a hour, be warming up to 80～85 ℃ and be incubated half a hour;

(2) the letex polymerization stage: 1～3 part of emulsifying agent, 60～80 parts of shell monomers, 0.4～0.6 part of initiator and 30～50 parts of deionized waters are added reaction kettle; Pre-emulsion was processed in emulsification in 1 hour in advance; In 3 hours, it is added in the seed emulsion, add 0.0004 part of initiator of total monomer amount and be incubated 1 hour, drop to normal temperature and filter discharging; Transfer PH to 8～9 at last, make modified acrylate emulsion.

2. the method for claim 1, its said emulsifying agent are that CO-436 or CO-458:CO-897 or CO-630 are by portion rate 1 :1.5～1 :3.5 the composite use of ratio.

3. the method for claim 1, its said nuclear layer monomer is Bing Xisuandingzhi and TEB 3K.

4. the method for claim 1; Its said shell monomers is that in TEB 3K, Bing Xisuandingzhi, vinylformic acid, methylacrylic acid, the Hydroxyethyl acrylate one or more mix by arbitrary proportion, wherein contains reactive group monomer Hydroxyethyl acrylate and accounts for 0.03～0.2 part of total monomer amount.

5. the method for claim 1; Its said organo-siloxane is γ-(methacryloxypropyl) propyl trimethoxy silicane: KH-570, γ-An Bingjisanyiyangjiguiwan: KH-550 and γ-glycidyl ether oxygen propyl trimethoxy silicane: one or more among the KH-560 are pressed arbitrary proportion and are mixed, and the organo-siloxane consumption accounts for 0.04～0.06 part of nano silicon solids content in the silicon sol.

6. the method for claim 1, its said initiator are a kind of in ammonium persulfate, the Potassium Persulphate-sodium sulfite anhy 96, and consumption accounts for 0.003～0.012 part of total monomer quality.

7. the method for claim 1, its said small molecular alcohol is one or more in ethanol, propyl alcohol and the terepthaloyl moietie.

8. the method for claim 1, its described acidic silicasol, particle diameter are 10～20nm, solid content is 25%～26%.