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

An acidic silica sol, acrylate technology, applied in the direction of coating, can solve the problems of secondary agglomeration, complicated operation, complicated modification process, etc., to avoid secondary dispersion, improve stability, and improve the effect of hardness

Inactive Publication Date: 2012-07-25
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

Publication No. CN102030873A "A Preparation Method of Nano-Silicon Dioxide/Polyacrylate Composite Emulsion" introduces the modification method of nano-silicon dioxide in detail, mainly using emulsifier, silane orthosilicate at room temperature. 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 more used is in-situ emulsion polymerization, for example, the publication number is CN 1908022 "a kind of preparation method of inorganic nanoparticle modified self-crosslinking acrylate emulsion at room temperature", which describes the preparation of orthosilicate in ethanol After the nano-silica is modified, it is modified with silicone, and then dispersed in the acrylate monomer for in-situ emulsion polymeriza

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Implement the preparation method of a kind of acidic silica sol situ modified acrylate emulsion provided by the present invention, carry out as follows:

[0033] 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 of KH-560 to the reactor, 50°C The mixture was stirred and reacted for 3 hours to obtain a modified silica sol.

[0034] 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, and add 0.16kg of NaHCO 3 and 2kg of deionized water...

Embodiment 2

[0037] 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 3

[0039] The modification methods of silica sol are different:

[0040] 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.

[0041] 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, 50°C The mixture was stirred and reacted for 3 hours to obtain a modified silica sol.

[0042] 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 m...

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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

technical field [0001] 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 [0002] 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 hydro...

Claims

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Application Information

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IPC IPC(8): C08F292/00C08F220/18C08F220/14C08F220/06C08F220/28C09D151/10
Inventor 刘世斌段东红李永超李一兵张忠林郝晓刚
Owner TAIYUAN UNIV OF TECH
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