Hydroxyl silica gel and preparation method thereof

Abstract

The invention provides hydroxyl silica gel and a preparation method thereof. The preparation method comprises the following steps: carrying out pre-drying treatment on hydroxyl-terminated polydimethylsiloxane; then adding a catalyst and a dialkoxy coupling agent into the treated raw material, heating under the protection of nitrogen, controlling the reaction temperature, and removing the temperature until a certain viscosity is reached; secondly, discharging nitrogen to vacuum, adding special amino silane, heating after adding the materials, preserving heat, stirring and reacting for several hours; and adding a reaction terminator after the reaction is finished, keeping the temperature for a certain time, and cooling to obtain the product. The hydrophilic amino silicon oil has the advantages of easily available synthesis raw materials, extremely low ring content and no solvent reaction, the response to low ring product requirements and low VOC (volatile organic compound) limitation of the current organic silicon material and the urgent demand of hydrophilic functional silicon oil is very matched, the synthesis process route is easy for industrial production, and the hydrophilic amino silicon oil product synthesized by the method is particularly smooth in hand feeling, fine and elastic, and has a good market prospect. The anti-yellowing agent is extremely low in yellowing property and can be commonly used in the fields of textile after-finishing auxiliaries, daily chemical care additives and the like.

Description

Technical Field

[0001] The invention relates to the technical field of silicone oil synthesis, in particular to a hydroxy silica gel and a preparation method thereof, belonging to the technical field of organic silicon. Background Art

[0002] Epoxy silicone oil and amino silicone oil are the most classic and effective silicone oil representatives of various modified silicone softeners in the early stage. At present, the main synthesis and preparation method is the ring-opening copolymerization method, which uses dimethyl mixed ring body (DMC) or octamethylcyclotetrasiloxane (D4) and epoxy (or amino) capping agent to polymerize at high temperature under alkaline catalyst conditions and complete it through vacuum de-low concentration. The product synthesis process takes a long time and consumes a lot of energy. It is difficult for the product to meet the low ring body standard (the environmental protection requirements are strict and the EU regulations have introduced low ring body restrictions). The product structure is difficult to meet customers' needs for diversified product styles (hydrophilic, fluffy, high temperature resistant, high resilience, etc.) due to the limitation of raw materials (the market supply of epoxy monomer and amino monomer capping agent raw material structure is single and limited). Based on the synthesis technology problems existing in the above industrial needs, it is more economical and effective to develop a multifunctional intermediate raw material that is reactive, low ring body and easy to industrialize for modified silicone oil softeners. Summary of the invention

[0003] The invention provides a functional organosilicon polymer with low reactivity and easy industrial production.

[0004] In view of the above technical problems, the present invention provides a method for preparing hydroxy silica gel, wherein the preparation process comprises the following steps: The catalyst and the dialkoxy coupling agent are added to the hydroxyl-terminated polydimethylsiloxane, and the temperature is raised to react under the protection of nitrogen. The reaction temperature is controlled and vacuum-desorbed to a certain viscosity, and then the nitrogen is vented to obtain hydroxyl silica gel.

[0005] The hydroxyl-terminated polydimethylsiloxane is one or more of hydroxyl silicone oil, linear body, and low-viscosity 107 glue, wherein hydroxyl silicone oil specifically refers to hydroxyl-terminated polydimethylsiloxane with a viscosity of 10-50cts, linear body specifically refers to hydroxyl-terminated polydimethylsiloxane with a viscosity of 50-150cts, and low-viscosity 107 glue specifically refers to hydroxyl-terminated polydimethylsiloxane with a viscosity of 150-2000cts.

[0006] The hydroxyl-terminated polydimethylsiloxane is dried and dehydrated to a water content of less than 100 ppm before use; the desiccant used for drying and dehydration comprises one or more of anhydrous sodium sulfate, anhydrous calcium chloride, molecular sieve, color-changing silica gel, and activated alumina; and the drying temperature is 5-110°C.

[0007] The catalyst is one or a mixture of polydimethylsiloxane polymer prepared by tetramethylammonium hydroxide, polydimethylsiloxane polymer prepared by tetraethylammonium hydroxide, polydimethylsiloxane polymer prepared by potassium hydroxide, phosphazene base ligand P4-tert-butyl, sodium methoxide. Among them, the polydimethylsiloxane polymer prepared as an alkaline catalyst is more conducive to the synthesis reaction. Since the organosilicon body has a relatively poor compatibility with both inorganic and organic compounds, the solubility of the single alkaline catalyst in the organosilicon intermediate or polymer raw material in the synthesis is extremely poor, resulting in poor dispersion of the reaction system and unsatisfactory catalytic effect; while the polydimethylsiloxane polymer prepared as an alkaline catalyst is the same as the organosilicon raw material body (intermediate or polymer), the two have excellent compatibility, excellent dispersion in the reaction polymerization monomer, uniform catalytic site activity and high activity, so it can accelerate the catalytic efficiency, shorten the reaction time and improve the degree of polymerization.

[0008] The dialkoxy coupling agent is one or more of dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, dimethyldipropoxysilane, diphenyldimethoxysilane, and methylphenyldimethoxysilane. As a traditional synthesis process of high molecular weight hydroxy polydimethylsiloxane polymer, it is mainly formed by condensation (producing water) between hydroxyl groups and hydroxyl groups in a high temperature system. It not only has high energy consumption, large catalyst dosage, but also is very easy to crack to generate ring bodies. The dialkoxy coupling agent used in the present invention is through the condensation of hydroxyl groups and alkyl groups (producing alcohol, methanol / ethanol), with low boiling point, low reaction energy barrier, milder condensation process conditions, and lower catalyst required for the reaction, which greatly reduces reaction energy consumption and side reactions, and has fewer low ring bodies.

[0009] The catalyst dosage is 0.~2000ppm; the dialkoxy coupling agent dosage is 0.01~20% of the mass of the hydroxyl-terminated polydimethylsiloxane; the reaction temperature is 20~80°C; the viscosity of the material after deoxidation is 5000-2000000 mPa.s; the hydroxyl value content of hydroxyl silica gel is 0.001%~0.150%; the low ring body content D4 is less than 0.1%, D5 is less than 0.2%, and D6 is less than 0.3%. Preferably, the amount of catalyst is 1-500ppm; the amount of dialkoxy coupling agent is 0.01-10% of the mass of hydroxyl-terminated polydimethylsiloxane; the desulfurization temperature is 20-50°C; preferably, the viscosity of the material after desulfurization is controlled to be 10000-1000000 mPa·s; the hydroxyl value content of hydroxyl silica gel is 0.002%-0.120%; the low ring body content D4 is less than 0.1%, D5 is less than 0.1%, and D6 is less than 0.2%.

[0010] Another technical solution of the present invention is to use the hydroxy silica gel in the preparation of epoxy silicone oil, that is, as an intermediate in the preparation of epoxy silicone oil.

[0011] The epoxy silicone oil contains epoxy-modified polydimethylsiloxane synthesized by using one or a mixture of 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane as silane monomers.

[0012] Another technical solution of the present invention is to use the hydroxy silica gel in the preparation of amino silicone oil, that is, as an intermediate in the preparation of amino silicone oil.

[0013] The amino silicone oil contains amino-modified polydimethylsiloxane synthesized with one or a mixture of NN diethylaminopropyl trimethoxysilane, NN dimethylaminopropyl trimethoxysilane, 3-(N,N-dimethylaminopropyl)-aminopropyl methyl dimethoxysilane, tetramethylammonium silanol, NN diethylaminopropyl triethoxysilane, piperazinyl propyl methyl dimethoxysilane, tetramethyldipropylene triaminopropyl methyl dimethoxysilane, NN diethylaminopropyl methyl dimethoxysilane, N,N-dimethylpropylene diaminopropyl methyl dimethoxysilane, NN diethylaminopropyl trimethoxysilane, and 3-(N-cyclohexylamino)propyl methyl dimethoxysilane as silane monomers.

[0014] The present invention utilizes the characteristics of extremely easy condensation of a dialkoxy coupling agent and hydroxyl-terminated polydimethylsiloxane and adopts a vacuum condensation polymerization equilibrium process at low temperature (minimum less than 80° C.) using a high-activity catalyst, which greatly reduces energy consumption and procedures, and can avoid cooling after high-temperature polycondensation, making it easier to react continuously and more conducive to industrial production; at the same time, by controlling the amount of catalyst, it can be avoided that too much catalyst and too high temperature cause the polymer to depolymerize into a high ring body, and the product synthesis yield is higher and the ring body is lower. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below through examples, but the examples are not intended to limit the scope of protection of the present invention. The raw materials used in the examples can be purchased from the market or prepared by conventional methods. In addition, for ease of understanding, the hydroxyl-terminated polydimethylsiloxane of the present invention has a molecular formula of HO-Si(CH 3 ) 2 O[Si(CH 3 ) 2 O]nSi(CH 3 ) 2-OH; the main commercial forms include linear body, hydroxy silicone oil and low viscosity 107 glue, and the relevant basic indicators are viscosity (25℃, mPa﹒s): ≤ 2000; volatile matter (150℃*3h, %): ≤ 1.5; hydroxyl content (hydroxyl mass percentage, %): ≤ 2.5.

[0016] The present invention is one or a mixture of tetramethylammonium hydroxide and polydimethylsiloxane polymer prepared therefrom, tetraethylammonium hydroxide and polydimethylsiloxane polymer prepared therefrom, potassium hydroxide and polydimethylsiloxane polymer prepared therefrom, organic phosphazene base ligand P4-tert-butyl and its solution, and sodium methoxide.

[0017] For example, the polydimethylsiloxane polymer prepared by tetramethylammonium hydroxide is prepared by using tetramethylammonium hydroxide and raw material hydroxyl-terminated polydimethylsiloxane at 80-95°C, nitrogen gas (flow rate controlled at 2-3L / min) is passed through the bottom for 3-4 hours to obtain a colorless, transparent, viscous liquid (polymer liquid yield is about 89-95%), wherein the concentration of tetramethylammonium hydroxide is 0.1-3.0%. Similarly, the method for preparing a catalyst by replacing tetramethylammonium hydroxide with tetraethylammonium hydroxide (or its hydrate) is the same as above.

[0018] The polydimethylsiloxane polymer prepared by potassium hydroxide is prepared by reacting KOH with the raw material hydroxyl-terminated polydimethylsiloxane at 120-150°C and keeping the temperature for 5 hours with nitrogen passing through the bottom (the flow rate is controlled at 1-2L / min) to obtain a colorless, transparent, viscous liquid (the yield of the high molecular polymer liquid is about 85-95%). A colorless, transparent, viscous liquid (viscosity (25°C, 100-6000cps, KOH concentration 0.1-3.0%) is obtained.

[0019] The conventional physical and chemical properties and application-related properties of the products at each stage in each embodiment are measured and calculated as follows: (1) Viscosity measurement: Rotary digital viscometer SNB-4T (0.1-2000000 mPa.s).

[0020] (2) Moisture determination: Coulometric Karl Fischer moisture meter (HOGON).

[0021] (3) Determination of hydroxyl value: Determined according to the method for determining hydroxyl value in national standard GB / T 18466-2008.

[0022] (4) Determination of low-ring D4 / D5 / D6: Use the methods specified in EPA 3550C:2007 and EPA 8270E:2018.

[0023] Example 1 Add 700 parts of hydroxy silicone oil (Hubei Xingtuo New Materials Technology Co., Ltd., viscosity 38cts, hydroxyl content 4.5%) to a clean and dry 1000ml three-necked reaction flask, add 20 parts of 4A molecular sieves under stirring, and filter at 35℃ for half an hour for stirring and adsorption (the water content of the filtrate is 30.5ppm). Transfer the filtrate to 680 parts of a 1000ml four-necked reaction flask, after nitrogen is evacuated, add 2 parts of dimethyldimethoxysilane, 0.68 parts of phosphazene base ligand P4-tert-butyl (hexane solvent, mass solubility 0.50%), heat to 50℃, control the negative pressure to -0.99MPa to remove the low, and release the nitrogen to obtain 670 parts of hydroxy silica gel A (viscosity measured 325000 mPa.s, hydroxyl value content of hydroxy silica gel 0.010%; low ring body content D4 is 0.055%, D5 is 0.086%, D6 is 0.150%), and the yield is 95.71%.

[0024] Example 2 Add 700 parts of hydroxy silicone oil (Hubei Xingtuo New Materials Technology Co., Ltd., viscosity 26cts, hydroxyl content 8.9%) to a clean and dry 1000ml three-necked reaction bottle, add 20 parts of 4A molecular sieve under stirring, and filter at 35℃ for half an hour for stirring and adsorption (the water content of the filtrate is 40ppm). Transfer the filtrate to 685 parts of a 1000ml four-necked reaction flask, after nitrogen is evacuated, add 2 parts of dimethyldiethoxysilane, 0.69 parts of an organic phosphazene base solution (hexane solvent, mass solubility 0.50%), heat to 60℃, control the negative pressure to -0.99MPa to remove the low, and release the nitrogen to obtain hydroxy silica gel A. (The viscosity is measured to be 285000 mPa.s, the hydroxyl value content of hydroxy silica gel is 0.015%; the low ring body content D4 is 0.058%, D5 is 0.076%, and D6 is 0.158%) 672 parts, the yield is 95.93%.

[0025] Example 3 Add 700 parts of hydroxy silicone oil (Hubei Xingtuo New Materials Technology Co., Ltd., viscosity 26cts, hydroxyl content 8.9%) to a clean and dry 1000ml three-necked reaction flask, add 35 parts of 4A molecular sieves under stirring, and filter at 45℃ for half an hour for stirring and adsorption (the water content of the filtrate is 35ppm). Transfer the filtrate to 685 parts of a 1000ml four-necked reaction flask, evacuate the nitrogen, add 2 parts of dimethyldimethoxysilane, 0.65 parts of polydimethylsiloxane polymer prepared by tetramethylammonium hydroxide (tetramethylammonium hydroxide mass solubility 0.50%), heat to 45℃, control the negative pressure to -0.99MPa to remove the low, and evacuate the nitrogen to obtain 657 parts of hydroxy silica gel A (viscosity measured 235000 mPa.s, hydroxyl value content of hydroxy silica gel 0.017%; low ring body content D4 is 0.087%, D5 is 0.096%, D6 is 0.188%), and the yield is 93.83%.

[0026] Example 4 Add 700 parts of hydroxy silicone oil (Hubei Xingrui Silicon Materials Co., Ltd., linear body 70cts, hydroxyl content 1.5%) to a clean and dry 1000ml three-necked reaction bottle, add 35 parts of 4A molecular sieves under stirring, and filter at 45℃ for half an hour under stirring and adsorption (the water content of the filtrate is 25ppm). Transfer the filtrate to 685 parts of a 1000ml four-necked reaction flask, evacuate the nitrogen, add 2 parts of methylphenyldimethoxysilane, 0.65 parts of polydimethylsiloxane polymer prepared by tetraethylammonium hydroxide (tetraethylammonium hydroxide mass solubility 0.50%), heat to 60℃, control the negative pressure to -0.99MPa to remove the low, and release the nitrogen to obtain 654 parts of hydroxy silica gel A (viscosity measured 255000 mPa.s, hydroxyl value content of hydroxy silica gel 0.013%; low ring body content D4 is 0.086%, D5 is 0.094%, D6 is 0.169%), and the yield is 93.45%. .

[0027] Example 5 The hydroxy silica gel A prepared in Example 1 was used to prepare amino silicone oil, and the preparation method was as follows: 34 parts of NN diethylaminopropyl trimethoxysilane were added to 670 parts of hydroxy silica gel A raw material, and 0.40 parts of phosphazene base ligand P4-tert-butyl (hexane solvent, mass solubility 0.5%) were added under nitrogen protection and stirred, and the mixture was kept at 50°C for 3 hours under nitrogen protection. Then 0.4 parts of silicic acid (concentration 0.5%, ethanol solvent) was added dropwise, and the mixture was kept at 50°C for 0.5 hours. The mixture was cooled to room temperature and discharged to obtain a colorless, transparent, viscous liquid. The product yield was 97.10%. The specific structural formula of the hydrophilic amino silicone oil is: Among them, (a+b+c)=90~100.

[0028] The prepared low-ring hydrophilic amino silicone oil sample was subjected to PL-GPC50 gel permeation chromatography, with polysiloxane as the standard sample and toluene as the mobile phase, and the weight average molecular weight, number average molecular weight and polydispersity index (PDI) of the prepared silicone oil sample were measured to be 6530, 5661 and 1.95 respectively; the viscosity of the low-ring hydrophilic amino silicone oil product at 25°C was 120 mPa.s measured by a rotational viscometer. The main ring body content of the sample was determined to be D4: 0.0126%, D5: 0.0398%, and D6: 0.0524%.

[0029] Example 5 The hydroxy silica gel A prepared in Example 2 was used to prepare epoxy silicone oil, and the preparation method was as follows: 30 parts of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane were added to 672 parts of hydroxy silica gel A raw material, and 0.60 parts of phosphazene base ligand P4-tert-butyl (hexane solvent, mass solubility 0.5%) were added under nitrogen protection, and the mixture was kept at 55°C for 3 hours under nitrogen protection. Then 0.4 parts of silicic acid (concentration 0.5%, ethanol solvent) were added dropwise, and the mixture was kept at 50°C for 0.5 hours. The mixture was cooled to room temperature and discharged to obtain a light yellow transparent viscous liquid. The product yield was 96.80%. The specific structural formula of epoxy silicone oil is:

[0030] The low-ring epoxy silicone oil sample prepared was measured by PL-GPC50 gel permeation chromatography, with polysiloxane as the standard sample and toluene as the mobile phase. The weight average molecular weight of the prepared silicone oil sample was 8560, the number average molecular weight was 9361, and the polydispersity index PDI was 1.93; the viscosity of the low-ring epoxy silicone oil product at 25°C was 168mPa.s using a rotational viscometer. The main ring body content of the sample was determined to be D4: 0.0626%, D5: 0.0802%, and D6: 0.0963%.

[0031] Comparative Example 1 The comparative example process is consistent with Example 1 except that 0.68 parts of polydimethylsiloxane polymer prepared by KOH (catalyst concentration 0.50%) is used as a catalyst.

[0032] This comparative example was used to prepare amino silicone oil again using Example 5, and the obtained light yellow transparent viscous liquid had a product yield of 93.78%, a weight average molecular weight of 20528, a number average molecular weight of 19213, and a polydispersity index PDI of 2.16; the viscosity of the product at 25°C was 960 mPa.s. The main ring body content of the sample was determined to be D4: 0.0966%, D5: 0.1685%, and D6: 0.2952%.

Claims

1. A method for preparing hydroxy silica gel, characterized in that: The preparation process comprises the following steps: The catalyst and the dialkoxy coupling agent are added to the hydroxyl-terminated polydimethylsiloxane, and the temperature is raised to react under the protection of nitrogen. The reaction temperature is controlled and vacuum-desorbed to a certain viscosity, and then the nitrogen is vented to obtain hydroxyl silica gel.

2. The method for preparing hydroxy silica gel according to claim 1, characterized in that: The hydroxyl-terminated polydimethylsiloxane is one or more of hydroxyl silicone oil, linear body, and low-viscosity 107 glue, wherein the viscosity of the hydroxyl silicone oil is 10-50cts, the viscosity of the linear body is 50-150cts, and the viscosity of the low-viscosity 107 glue is 150-2000cts.

3. The method for preparing hydroxy silica gel according to claim 1, characterized in that: The hydroxyl-terminated polydimethylsiloxane is dried and dehydrated to a water content of less than 100 ppm before use; the desiccant used for drying and dehydration comprises one or more of anhydrous sodium sulfate, anhydrous calcium chloride, molecular sieve, color-changing silica gel, and activated alumina; and the drying temperature is 5-110°C.

4. The method for preparing hydroxy silica gel according to claim 1, characterized in that: The catalyst is one or a mixture of polydimethylsiloxane polymer prepared by tetramethylammonium hydroxide, polydimethylsiloxane polymer prepared by tetraethylammonium hydroxide, polydimethylsiloxane polymer prepared by potassium hydroxide, phosphazene base ligand P4-tert-butyl, sodium methoxide, and the catalyst dosage is 0.5-2000ppm.

5. The method for preparing hydroxy silica gel according to claim 1, characterized in that: The dialkoxy coupling agent is one or more of dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, dimethyldipropoxysilane, diphenyldimethoxysilane, and methylphenyldimethoxysilane; the amount of the dialkoxy coupling agent is 0.01-20% of the mass of the hydroxyl-terminated polydimethylsiloxane.

6. The method for preparing hydroxy silica gel according to claim 1, characterized in that: The reaction temperature is 20~80℃; the viscosity of the material after degassing is 5000-2000000 mPa.s.

7. The hydroxy silica gel according to any one of claims 1 to 6, characterized in that The hydroxyl value content of the hydroxyl silica gel is 0.001%~0.150%; the low ring body content D4 is less than 0.1%, D5 is less than 0.2%, and D6 is less than 0.3%.

8. Use of the hydroxy silica gel according to claim 7 in the preparation of epoxy silicone oil, characterized in that: The epoxy silicone oil contains epoxy-modified polydimethylsiloxane synthesized by using one or a mixture of 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane as silane monomers.

9. Use of the hydroxy silica gel according to claim 7 in the preparation of amino silicone oil, characterized in that: The amino silicone oil contains amino-modified polydimethylsiloxane synthesized with one or a mixture of NN diethylaminopropyl trimethoxysilane, NN dimethylaminopropyl trimethoxysilane, 3-(N,N-dimethylaminopropyl)-aminopropyl methyl dimethoxysilane, tetramethylammonium silanol, NN diethylaminopropyl triethoxysilane, piperazinyl propyl methyl dimethoxysilane, tetramethyldipropylene triaminopropyl methyl dimethoxysilane, NN diethylaminopropyl methyl dimethoxysilane, N,N-dimethylpropylene diaminopropyl methyl dimethoxysilane, NN diethylaminopropyl trimethoxysilane, and 3-(N-cyclohexylamino)propyl methyl dimethoxysilane as silane monomers.

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