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CN-122006296-A - High-content organic silicon defoamer composition and preparation method thereof

CN122006296ACN 122006296 ACN122006296 ACN 122006296ACN-122006296-A

Abstract

The invention relates to the technical field of defoamer preparation, in particular to a high-content organic silicon defoamer composition and a preparation method thereof. The preparation method comprises the steps of preparing methyl hydrogen polysiloxane precursor through fractional ring opening polymerization, sequentially introducing allyl polyether end-capped polymer, active allyl methoxy end-capped polyether and active allyl epoxy end-capped polyether to obtain a core organosilicon active component, and then compounding the core organosilicon active component with simethicone and hydrophobic fumed silica to obtain a high-content organosilicon defoamer composition, wherein the obtained composition has quick initial defoaming, good continuous foam inhibition performance, lower oil separation rate and quick redispersion speed in high-alkali high-salt white water, alkali washing liquid and high-salt liquid.

Inventors

  • WANG PIYE
  • LI XIANGJIANG
  • MENG DEQIAN

Assignees

  • 济宁金汉斯环保材料股份有限公司

Dates

Publication Date
20260512
Application Date
20260409

Claims (10)

  1. 1. A method for preparing a high-content silicone defoamer composition, comprising the steps of: (1) Sequentially adding anhydrous toluene, hexamethyldisiloxane and octamethyl cyclotetrasiloxane into a reactor, adding trifluoromethanesulfonic acid for ring-opening polymerization, then adding 2,4,6, 8-tetramethyl cyclotetrasiloxane for continuous reaction, and adding octamethyl cyclotetrasiloxane again for continuous reaction to obtain methyl hydrogen polysiloxane precursor; (2) Mixing methyl hydrogen polysiloxane precursor with anhydrous toluene, adding allyl polyether end-capped polymer to perform a first grafting reaction under the catalysis of platinum-divinyl tetramethyl disiloxane complex xylene solution, adding active allyl methoxy end-capped polyether to perform a second grafting reaction, adding active allyl epoxy end-capped polyether to perform a third grafting reaction, adding active carbon after the reaction is completed, filtering and removing toluene to obtain a core organosilicon active component; (3) Mixing the core organic silicon active component and the simethicone to form an oil phase, pre-wetting part of the core organic silicon active component and the hydrophobic fumed silica to form pre-dispersed slurry, adding the pre-dispersed slurry back into the oil phase, adding the hydrophobic fumed silica into the system for dispersion and defoaming to obtain the high-content organic silicon defoamer composition.
  2. 2. The method of claim 1, wherein the weight ratio of hexamethyldisiloxane, octamethyl cyclotetrasiloxane, 2,4,6, 8-tetramethyl cyclotetrasiloxane, and octamethyl cyclotetrasiloxane added again in step (1) is 11-13:118-122:4-6:28-32.
  3. 3. The process according to claim 1, wherein the ring-opening polymerization temperature in step (1) is 30 to 33℃and the reaction time is 18 to 22 minutes.
  4. 4. The method of claim 1, wherein the weight ratio of methyl hydrogen polysiloxane precursor, allyl polyether cap, reactive allyl methoxy cap polyether, and reactive allyl epoxy cap polyether of step (2) is 155-165:30-34:14-16:4-6.
  5. 5. The process of claim 1 wherein the allyl polyether cap of step (2) has an average molecular weight of 750, a moisture content of not more than 0.15%, an unsaturation of not less than 1.2mmol/g, and a cap ratio of not less than 95%.
  6. 6. The process of claim 1 wherein the reactive allylmethoxy-terminated polyether of step (2) has an average molecular weight of 500, a moisture content of no more than 0.5%, and a termination of no less than 90%.
  7. 7. The process of claim 1, wherein the reactive allylic epoxy-terminated polyether of step (2) has an average molecular weight of 450, an epoxy value of not less than 1.90eq/1000g, and a double bond content of 2.00-2.35mmol/g.
  8. 8. The method of claim 1, wherein the weight ratio of the core silicone active component, the simethicone, a portion of the core silicone active component, and the hydrophobic fumed silica in step (3) is 68-74:18-24:7-9:7.2-8.8.
  9. 9. The process according to claim 1, wherein the deaeration in step (3) is carried out at 55 ℃ and 10 kPa.
  10. 10. The high-content organic silicon defoamer composition is characterized by being prepared by the preparation method according to any one of claims 1-9, and comprises, by weight, 75-83 parts of a core organic silicon active component, 18-24 parts of simethicone and 7.2-8.8 parts of hydrophobic fumed silica.

Description

High-content organic silicon defoamer composition and preparation method thereof Technical Field The invention relates to the technical field of defoamer preparation, in particular to a high-content organic silicon defoamer composition and a preparation method thereof. Background The organosilicon defoamer is widely applied to the industrial fields of papermaking, textile, water treatment, chemical washing and the like because of low surface tension, strong foam breaking capability and outstanding chemical inertness. In high-alkali and high-salt industrial water systems such as papermaking white water, alkali washing liquid and the like, the problem of foam is particularly serious, the production efficiency and the normal operation of equipment are affected, and the quality of products is possibly reduced. The polyether modified organosilicon defoamer improves the dispersibility and foam inhibition durability of the traditional polysiloxane defoamer in the water phase to a certain extent by introducing hydrophilic polyether chain segments, and becomes one of the main technical routes of the current industrial defoamer. However, the existing high-content organosilicon defoamer still exposes a plurality of short plates which are difficult to be compatible with the severe working conditions of high alkali, high salt, high shearing and circulating bubbling. From the molecular structure level analysis, the commercial polyether modified organosilicon product usually adopts a full-chain random grafting mode, namely polyether chain segments are indiscriminately distributed on each silica unit of a polysiloxane main chain, and the molecular weight distribution of polyether is wider. The structural design is relatively simple, but has three inherent defects that firstly, a polysiloxane main chain originally has extremely strong hydrophobicity, after polyether chain segments are randomly grafted, the hydrophobic and hydrophilic segments are in disordered alternate distribution, so that the arrangement behavior of molecules at an interface of a water phase is disordered, a large number of hydrophobic main chains cannot be effectively shielded at the initial stage of adding a defoaming agent into a foaming liquid, so that liquid drops are difficult to spread quickly and infiltrate into a foaming film, the liquid drops are slow in liquid-entering dispersion speed and lag in defoaming effect, secondly, in the quick foam breaking stage, the randomly grafted polyether chain segments are often concentrated outside the main chain and are easy to contact with the water phase prematurely, a hydrophobic region for maintaining the rupture driving force of the foaming film is consumed, so that the initial foam breaking is faster, but as bubbles are repeatedly generated, the polyether chain segments are gradually swelled or hydrolyzed by the water phase, the interface re-spreading capability is rapidly reduced, the foam suppressing effect is obviously attenuated after multiple cycles, and thirdly, the random distribution of the polyether chain segments destroys the regularity of polysiloxane molecular chains, so that the compatibility between different molecules is poor, low molecular weight components are easy to aggregate in the storage process, the free oil phase is formed, the content of the free oil phase is easy to be high, namely the foam is remarkably stable in an oil-absorbing system, and the stability of a product is remarkably high in an oil content of an oil-absorbing system (95% and is usually used in a high-quality and good-quality product. At present, the problems are often avoided by adopting a block copolymerization structure, introducing a cross-linking agent or adding a thickening stabilizer, etc., but the methods either increase the complexity of the preparation process or trade off stability at the expense of partial defoaming activity, and the ideal balance among the three of rapid foam breaking, continuous foam inhibition and storage stability is not always achieved. Disclosure of Invention In view of the above, the invention aims to provide a high-content organic silicon defoamer composition and a preparation method thereof, so as to solve the problem that the prior art cannot realize the synchronous promotion of rapid foam breaking, alkali-resistant continuous foam inhibition and storage stability. Based on the above purpose, the invention provides a preparation method of a high-content organic silicon defoamer composition, which comprises the following specific steps: (1) Sequentially adding anhydrous toluene, hexamethyldisiloxane and octamethyl cyclotetrasiloxane into a reactor, adding trifluoromethanesulfonic acid for ring-opening polymerization, then adding 2,4,6, 8-tetramethyl cyclotetrasiloxane for continuous reaction, adding octamethyl cyclotetrasiloxane again for continuous reaction, immediately adding light magnesium oxide for neutralization after the reaction is finished, filtering to remove a neu