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CN-121270931-B - Organosilicon foam stabilizer and preparation method thereof

CN121270931BCN 121270931 BCN121270931 BCN 121270931BCN-121270931-B

Abstract

The invention relates to the technical field of foam material assistants, in particular to an organosilicon foam stabilizer and a preparation method thereof. The stabilizer is prepared by grafting monoallyl polyether, diallyl polyether and MQ silicone resin containing vinyl respectively through segmental hydrosilation based on a siloxane copolymerization main chain containing a silicon-hydrogen bond and a phenyl segment. The stabilizer has excellent thermal stability, interfacial film forming strength and system compatibility in the high-temperature polyurethane foaming process, can effectively improve the foam height retention rate, refine cells, reduce aperture ratio and obviously improve sagging, and is suitable for high-index, high-polarity and environment-friendly foaming formulas. By introducing the phenyl segment and covalent grafting MQ structural domain, the invention realizes the optimal control of the molecular thermal stability and the interface structure of the foam stabilizer, and has important significance for improving the high-temperature molding quality of the polyurethane foam.

Inventors

  • ZHANG CHAOCHEN
  • LI ZHIGANG

Assignees

  • 山东思德新材料科技有限公司

Dates

Publication Date
20260508
Application Date
20250930

Claims (10)

  1. 1. The organic silicon foam stabilizer is characterized in that the organic silicon foam stabilizer is prepared by reacting a siloxane copolymerization main chain containing silicon hydrogen bonds and phenyl fragments with monoallyl polyether, diallyl polyether and vinyl-containing MQ silicon resin in a segmented hydrosilation mode, wherein the siloxane copolymerization main chain contains fragments obtained by ring-opening copolymerization of octamethyl cyclotetrasiloxane, methyl phenyl cyclotrisiloxane and methyl hydrogen cyclotrisiloxane, the silicon hydrogen bonds are reserved in the main chain, the vinyl-containing MQ silicon resin is covalently grafted to the main chain through silicon-hydrogen addition, the monoallyl polyether and the diallyl polyether are grafted to the main chain through silicon-hydrogen addition, and the hydrosilation sequence comprises grafting monoallyl polyether, grafting diallyl polyether, grafting vinyl-containing MQ silicon resin and supplementing grafted monoallyl polyether.
  2. 2. The organic silicon foam stabilizer according to claim 1, wherein the siloxane copolymerization main chain is prepared by ring-opening copolymerization of 300 parts by mass of octamethyl cyclotetrasiloxane, 40-100 parts by mass of methyl phenyl cyclotrisiloxane, 70-130 parts by mass of methyl hydrogen cyclotrisiloxane, 5 parts by mass of hexamethyldisiloxane and 1 part by mass of potassium hydroxide.
  3. 3. The silicone foam stabilizer according to claim 1, wherein the monoallyl polyether is prepared by adding allyl alcohol to propylene oxide, and the mass ratio of allyl alcohol to propylene oxide is 6:116.
  4. 4. The organosilicon foam stabilizer according to claim 1, wherein the diallyl polyether is prepared by reacting 1, 3-propanediol, propylene oxide and allyl glycidyl ether, and the mass ratio of the 1, 3-propanediol, propylene oxide and allyl glycidyl ether is 8:120:40.
  5. 5. The organic silicon foam stabilizer according to claim 1, wherein the vinyl-containing MQ silicon resin is prepared by hydrolytic polycondensation of silicon tetrachloride, trimethylchlorosilane and vinyltrichlorosilane in a solvent, and the mass ratio of the silicon tetrachloride, the trimethylchlorosilane and the vinyltrichlorosilane is 50:80:20.
  6. 6. The organic silicon foam stabilizer according to claim 1, wherein the silicone copolymerized main chain is added with the grafting component in the hydrosilation grafting stage in the mass part of 17.5-40 parts of monoallyl polyether, 7.5-15 parts of diallyl polyether, 4-10 parts of vinyl-containing MQ silicone resin and 4-7.5 parts of monoallyl polyether in the supplementary addition amount based on 100 parts by mass of the silicone copolymerized main chain.
  7. 7. A method of preparing the silicone foam stabilizer according to any one of claims 1 to 6, comprising the steps of: (1) Preparing a siloxane copolymerization main chain containing a silicon-hydrogen bond and a phenyl fragment, namely carrying out anion ring-opening polymerization under the protection of nitrogen, distilling to remove low-boiling substances, neutralizing, and stripping the neutralizing agent to constant weight under reduced pressure; (2) Preparing diallyl polyether; (3) Preparing monoallyl polyether; (4) Preparing a vinyl-containing MQ silicone resin; (5) Preparing a platinum complex catalyst solution; (6) And (3) segmented hydrosilation grafting, namely sequentially carrying out hydrosilation reaction on the siloxane copolymerization main chain, monoallyl polyether, diallyl polyether and vinyl-containing MQ silicon resin in a solvent, adding monoallyl polyether in a supplementary manner, adding an antioxidant, and then removing the solvent under reduced pressure to constant weight to obtain the organosilicon foam stabilizer.
  8. 8. The method for producing a silicone foam stabilizer according to claim 7, wherein the production conditions of the silicone copolymerized main chain in step (1) are that the anionic ring-opening polymerization is carried out by stirring for 6 hours at 60 ℃, the temperature is raised to 120 ℃, distillation is carried out under 15 kPa under reduced pressure until the distillation rate is less than 0.5 g/min, the temperature is lowered to 80 ℃,2 parts by mass of tributyl phosphate is added for neutralization, and the temperature is raised to 120 ℃, and the silicone copolymerized main chain is peeled off to constant weight under 10 kPa under reduced pressure.
  9. 9. The method for preparing a silicone foam stabilizer according to claim 7, wherein the specific preparation step of the platinum complex catalyst solution in step (5) is that 5 parts by mass of chloroplatinic acid hexahydrate is dissolved in 95 parts by mass of isopropanol, and 10 parts by mass of divinyl tetramethyl disiloxane is added and stirred for 1 hour to obtain a platinum complex catalyst solution.
  10. 10. The method for preparing the organic silicon foam stabilizer according to claim 7, wherein the specific steps of the segmented hydrosilation grafting in the step (6) are that a siloxane copolymerization main chain containing a silicon hydrogen bond and a phenyl segment is added into cyclohexane, nitrogen is introduced to protect and heat up to 55-70 ℃, after a platinum complex catalyst solution is added and stirred for 30min, monoallyl polyether is slowly added dropwise, the reaction is maintained at 55-70 ℃ for 2h, a platinum complex catalyst solution is added and heat up to 70-85 ℃, diallyl polyether is added dropwise, the reaction is carried out for 3h, the reaction temperature is reduced to 60-75 ℃, then vinyl MQ silicone resin is added for 2h, monoallyl polyether is added into the reaction system for reaction for 1h at 65-80 ℃, an antioxidant is added, stirring is carried out for 30min at 50 ℃, and then cyclohexane is distilled off to constant weight under the conditions of 60 ℃ and 0.5kPa, so that the organic silicon foam stabilizer is obtained.

Description

Organosilicon foam stabilizer and preparation method thereof Technical Field The invention relates to the technical field of foam material assistants, in particular to an organosilicon foam stabilizer and a preparation method thereof. Background Polyurethane foam materials are widely used in the fields of building heat preservation, cold chain storage and transportation, household appliance insulation and the like due to excellent heat insulation, light weight and processing adaptability. As environmental regulations become more stringent and application scenarios expand, polyurethane foams are evolving towards higher foaming temperatures, lower thermal conductivities, and harsher service environments. Under the background, the performance limitation of the traditional foam stabilizer under the high-temperature foaming condition is increasingly prominent, and the traditional foam stabilizer becomes a key bottleneck for restricting the technical progress of the industry. The organosilicon foam stabilizer is used as a core component of a polyurethane foaming system, and has the main functions of reducing the surface tension of liquid, stabilizing the cell structure and adjusting the reaction rate matching. The traditional organosilicon stabilizer is mostly based on a polydimethylsiloxane main chain, hydrophilic polyether chain segments are introduced through side chain modification, and the hydrophilic polyether chain segments migrate to a gas-liquid interface to form a monomolecular film in the foaming process, so that cell combination and rupture are inhibited. However, in high temperature foaming environments, conventional stabilizers face a number of technical challenges: First, insufficient thermal stability results in a decay in interfacial properties. In the high-temperature foaming process, the temperature of a reaction system can reach 100-150 ℃, and the traditional polydimethylsiloxane main chain is easy to pyrolyze and rearrange at the temperature, so that the molecular weight is degraded and the interfacial activity is reduced. Meanwhile, the thermal sensitivity of the siloxane bond enables the stabilizer to easily generate chain breakage in a high-temperature shearing environment, and the integrity of the interfacial film is destroyed, which is manifested by aggravation of cell combination and reduction of the high retention rate. Second, interfacial film strength and flowability are difficult to balance. The ideal foam stabilizer requires rapid spreading wetting at the nascent foam film while providing sufficient film strength to resist drainage late in cell expansion. The traditional stabilizer is mostly dependent on physical adsorption to form an interfacial film, lacks an effective intermolecular crosslinking mechanism, is easy to desorb and rearrange under the high-temperature and high-shear conditions, and is difficult to maintain the mechanical strength of the foam film. While an excessive increase in molecular weight can enhance film strength, it can sacrifice interfacial migration rate, leading to uneven incipient wetness in the foam, and uneven cell distribution. Again, compatibility with high polarity foaming systems is limited. The high-functionality polyol, the high-activity catalyst and the environment-friendly foaming agent are used in a large amount in the modern polyurethane formula, so that the polarity of the system is obviously enhanced. The hydrophobic siloxane main chain of the traditional organosilicon stabilizer has reduced compatibility in the system, is easy to generate microphase separation, and influences the uniformity and the continuity of interfacial film formation. The solubility and interfacial activity of the stabilizer is further challenged, particularly in systems employing HFO-based blowing agents. In addition, the prior art grafting modification methods have structural design limitations. The traditional hydrosilation reaction mostly adopts a one-step method or simple bi-component grafting, and the grafting density and distribution of different functional chain segments are difficult to accurately control, so that a large number of unreacted silicon-hydrogen bonds or incompletely grafted chain segments exist in the product. These structural defects not only affect the interfacial properties of the stabilizer, but may also continue to react during storage, affecting product stability. While the prior commercial products can alleviate the above problems to some extent by increasing the amount or compounding other adjuvants, it is often at the expense of cost effectiveness and formulation simplicity, and it is difficult to achieve an optimal balance between high retention and cell refinement. Therefore, the novel organosilicon foam stabilizer is developed, and through molecular structure optimization and preparation process innovation, the key technical problems of high-temperature stability, interfacial film forming strength, compatibility and the like are solv