Powder carbomer polymer as well as preparation method and application thereof

Abstract

The invention provides a powder carbomer polymer as well as a preparation method and application thereof. The powder carbomer is obtained by polymerizing an acrylate monomer containing unsaturated double bonds in a solvent in the presence of a cross-linking agent and a free radical initiator, wherein the acrylate monomer containing the unsaturated double bonds does not react completely, and the reaction degree of the acrylate monomer containing the unsaturated double bonds is 60-95%. According to the method, the thickening efficiency, transparency and ion resistance of the carbomer in practical application can be effectively improved, and meanwhile, the suspension performance of the carbomer in formula use is improved.

Description

Technical Field

[0001] This invention relates to the field of polymer material preparation, specifically to a powdered carbomer polymer, its preparation method, and its applications. Background Technology

[0002] With social development and population aging, the demand for personal care products has been increasing year by year, and the demand for powdered polyacrylate carbomer thickeners, which are widely used in these fields, is also increasing annually. Carbomer is a type of polymer material made by cross-linking polymerization of acrylic acid and its derivatives. Neutralized carbomer is an excellent gel matrix with excellent thickening, suspending, and emulsifying properties. It has good compatibility with other excipients and is often used as an adhesive, pharmaceutical excipient, and nutritional additive, especially in emulsions, creams, and gels. Its main mechanism of action is that when polyacrylate thickeners are added to water, the addition of alkaline substances neutralizes them, eliminating the hydrogen bonding between carboxyl groups. At the same time, the negative charge on the same molecular chain generates electrostatic repulsion, forcing the coiled molecular chains to change from a "spherical" shape to a "linearly extended" shape. The fully extended molecular chains intertwine and entangle to form a continuous three-dimensional network structure. Simultaneously, the carboxyl ions on the molecular weight are tightly bound to water molecules through hydrogen bonds, "locking" free water molecules, significantly reducing the fluidity of the system, thereby achieving a significant increase in viscosity. Its outstanding features include high thickening efficiency, good transparency, excellent rheological properties, and good biocompatibility.

[0003] CN114933680 discloses a salt-resistant carbomer and its preparation method. This patent uses acrylic acid copolymerized with allyl polyoxyethylene ether, combined with a pentaerythritol triallyl ether and allyl sucrose ether double crosslinking system to form an interpenetrating network structure, which significantly improves the stability and thickening properties of carbomer in high-salt systems.

[0004] CN114621397 discloses a method for preparing powdered carbomer. This patent describes a method for polymerizing acrylic acid in an ethyl acetate / cyclohexane mixed solvent using an oil-soluble initiator to obtain a white powdered carbomer with good aqueous dispersibility and thickening effect, suitable for personal care products.

[0005] CN103755861 discloses a method for preparing carbomer. It involves using water and tert-butanol as a mixed solvent, and then adding acrylic acid monomer, initiator, and crosslinking agent dropwise at a certain temperature to copolymerize and obtain an aqueous carbomer solution. Further dehydration and drying yields powdered carbomer. This method, by adding tert-butanol, provides a more inclusive and environmentally friendly aqueous reaction system, resulting in high-quality carbomer.

[0006] US3912921 discloses a method for preparing a copolymeric thickener. It mainly obtains a powdered thickener through copolymerization of acrylic acid and long-chain acrylates (C10–C30), exhibiting good water dispersibility and thickening properties, suitable for personal care and cosmetic formulations.

[0007] US20050027052 discloses a patent entitled "Method for Improving the Properties of Spray-Dried Powder and Particulate Materials". This patent uses spray drying technology to control the morphology and internal structure of carbomer particles, thereby achieving controllable adjustment of solubility, dispersibility and thickening properties.

[0008] WO2004013136 discloses a method for preparing a cross-linked polyacrylic acid thickener. Its key technical feature is the use of at least two different cross-linking agents for "internal cross-linking," followed by surface re-cross-linking treatment of the resulting powder, which further improves salt resistance and viscosity recovery after shearing.

[0009] In summary, existing technologies still suffer from problems such as low carbomer thickening efficiency, poor transparency, poor ion resistance, and poor suspension performance, which urgently need to be addressed. Summary of the Invention

[0010] One of the objectives of this invention is to provide a method for preparing powdered carbomer polymer, which can effectively improve the thickening efficiency, transparency and ion resistance of carbomer in practical applications, while also improving the suspension performance in formulations.

[0011] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0012] A method for preparing a powdered carbomer polymer, wherein the powdered carbomer is obtained by polymerizing acrylate monomers containing unsaturated double bonds in a solvent in the presence of a crosslinking agent and a free radical initiator; wherein the acrylate monomers containing unsaturated double bonds are not completely reacted, preferably the degree of reaction of the acrylate monomers containing unsaturated double bonds is 60-95% compared with the theoretical amount of 100% complete reaction, and more preferably 75-90%.

[0013] The technical solution of this invention involves interrupting the polymerization reaction when the unsaturated double-bond acrylate monomers have reacted to a degree of 60-95%, strictly controlling the reaction progress of the acrylate monomers. This is because when the degree of acrylate monomer reaction is below 60%, the overall polymerization is incomplete, the molecular weight of the polymer backbone is small, and the degree of entanglement between molecular chains is low, resulting in low thickening efficiency. Similarly, when the degree of acrylate monomer reaction is above 95%, the later-reacting acrylate monomers fill the gaps between the formed polymer particles, causing insufficient swelling of the polymer particles when alkali is added to the aqueous phase later, resulting in low thickening efficiency and low transparency. However, by controlling the degree of acrylate monomer reaction to 60-95%, the molecular weight of the polymer backbone is sufficiently large, the degree of entanglement between molecular chains is moderate, and the gaps between polymer particles are not blocked. This allows the polymer particles to fully swell during later neutralization and use, greatly improving the thickening efficiency and transparency of the aqueous phase, while also significantly improving the suspension performance of the formulation system.

[0014] In one embodiment of the present invention, the preparation method includes the following steps:

[0015] I. Add raw materials containing acrylate monomers with unsaturated double bonds and crosslinking agents to the solvent and mix;

[0016] II. Heat the mixture, add a free radical initiator to carry out the polymerization reaction, filter and separate the product, wash and dry it to obtain carbomer powder.

[0017] In one embodiment of the present invention, a stabilizer is added to I.

[0018] In one embodiment of the present invention, the solvent in I is selected from alkanes having 1 to 10 carbon atoms, and / or alkyl acetates or alkyl propionates having 1 to 4 carbon atoms in the alkyl group; wherein, preferably, the alkanes include one or more of n-hexane, cyclohexane, n-heptane, cycloheptane, and n-decane, wherein, preferably, the alkyl acetates include one or more of ethyl acetate, butyl acetate, ethyl propionate, and butyl propionate; preferably, the solvent is 4 to 8 times the total mass of the acrylate monomers containing unsaturated double bonds.

[0019] In one embodiment of the present invention, the polymerization temperature in II is 40-80°C and the polymerization time is 4-20h.

[0020] In one embodiment of the present invention, the drying temperature in II is 95-105°C, the vacuum degree is <-10 bar, and the drying time is 6-8 hours.

[0021] Another object of the present invention is to provide a powdered carbomer polymer.

[0022] A powdered carbomer polymer, wherein the polymer is prepared by the above-described preparation method, and the raw materials of the polymer include an acrylate monomer containing unsaturated double bonds, a crosslinking agent, a free radical initiator, and optionally a stabilizer.

[0023] In one embodiment of the present invention, the acrylate monomer containing unsaturated double bonds comprises unsaturated carboxylic acids containing double bonds, preferably one or more of acrylic acid, methacrylic acid, maleic acid, cinnamic acid, itaconic acid, fumaric acid, crotonic acid, and aconitic acid; preferably, the proportion of unsaturated carboxylic acids containing double bonds is 85-100 wt%, based on the acrylate monomer containing unsaturated double bonds.

[0024] In one embodiment of the present invention, the acrylate monomer containing an unsaturated double bond comprises a hydrophobic monomer with 11-22 carbon atoms and containing one unsaturated double bond, having the following general formula structure:

[0025]

[0026] Wherein, R1 is hydrogen or methyl, and R2 is an alkyl structure containing 8-18 carbon atoms; preferably, the proportion of hydrophobic monomers with 11-22 carbon atoms and containing one unsaturated double bond is 0-15 wt%, based on acrylate monomers containing unsaturated double bonds.

[0027] In one embodiment of the present invention, the crosslinking agent is at least one substance containing at least two unsaturated carbon-carbon double bonds, preferably a polyfunctional acrylate with at least two polymerizable olefinic double bonds, and / or a polyolefinic polyether with at least two polymerizable olefinic double bonds, more preferably the polyfunctional acrylate and polyolefinic polyether are formed by esterification or etherification of linear and / or branched polyols; preferably, the amount of crosslinking agent is 0.01-5 wt% of the total mass of the acrylate monomers with unsaturated double bonds, preferably 0.1-3 wt%, more preferably 0.5-2.5 wt%.

[0028] In one embodiment of the present invention, the free radical initiator is one or more of organic peroxide compounds, azo compounds, inorganic persulfate compounds, and hydrogen peroxide, preferably one or more of azobisisobutyronitrile, tert-butyl-2-ethylhexyl peroxide, di(2-ethylhexyl) percarbonate, benzoyl peroxide, dodecyl peroxide, ammonium persulfate, sodium persulfate, and hydrogen peroxide; preferably, the amount of free radical initiator is 0.02-2 wt% of the total mass of the acrylate monomers with unsaturated double bonds, more preferably 0.05-0.8 wt%.

[0029] In one embodiment of the present invention, the stabilizer is a nonionic emulsifier and / or an EO-PO copolymer block polyether; wherein the nonionic emulsifier preferably comprises a nonionic emulsifier with an HLB value of 1.6-5.6, more preferably one or more of sorbitan trioleate, propylene glycol monostearate, sorbitan monooleate, diethylene glycol monostearate, and glyceryl monostearate; wherein the EO-PO copolymer block polyether stabilizer preferably has a polyether structure with an EO content of less than 20%; BASF's products can be selected. PE3100 (10% EO), FT PE6200 (20% EO), PE8100 (10% EO), PE10100 (10% EO) and One or more of RPE1720 (20% EO); preferably, the amount of stabilizer is 0.05-2 wt% of the total mass of the unsaturated double bond acrylate monomers, preferably 0.1-0.6 wt%.

[0030] In one embodiment of the present invention, the powdered carbomer polymer has a specific surface area of ​​15-50 m² / g. The specific surface area is tested primarily according to the national standard method GB / T19587-2017 "Determination of Specific Surface Area of ​​Solid Substances by Gas Adsorption BET". The instrument used for testing the specific surface area in this invention is the ASAP-2460 model from Micron Instruments, Inc., USA.

[0031] In one embodiment of the present invention, the method for testing the acrylate monomers containing unsaturated double bonds in the powdered carbomer polymer is as follows:

[0032] The instrument configuration and chromatographic conditions described herein are as follows:

[0033] Agilent LC-2030C Liquid Chromatograph

[0034] Column: Agilent ZORBAX 300SB-C18 (4.6mm × 150mm, 5μm)

[0035] Injection volume: 5.0 μL

[0036] Mobile phase: 0.01 mol / L KH2PO4-methanol (95:5, v / v)

[0037] Flow rate: 1.00 ml / min

[0038] Column temperature: 30℃

[0039] Detection wavelength: 190-500nm

[0040] Washing method: isocratic washing

[0041] Another object of the present invention is to provide an application of powdered carbomer polymer.

[0042] An application of a powdered carbomer polymer, wherein the polymer is prepared by the above-described preparation method or is the above-described polymer, wherein the powdered carbomer polymer is used as a thickener for transparent gel media, preferably in the field of personal care.

[0043] Compared with the prior art, the advantages of this invention are as follows:

[0044] By effectively controlling the specific surface area of ​​polymer stacking, higher thickening efficiency, system transparency and ion resistance are provided, while the suspension performance of the formulation system can be improved. Detailed Implementation

[0045] To further understand the present invention, the technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Unless otherwise specified, all reagents involved in the embodiments of this invention are commercially available products and can be purchased through commercial channels.

[0047] The main raw materials and their information used in this embodiment are shown in the table below:

[0048]

[0049]

[0050] The main equipment information used in this embodiment is shown in the table below:

[0051] Equipment Name model factory Vacuum drying oven DZF-6050 Boxun vacuum pump PC3001 Vacuubrand mixer RW20 IKA Viscometer DVRV Bo Lifei Spectrophotometer Model 7200 Unico Dissolved oxygen meter F4-Standard Mettler homogenizer T25 IKA Specific surface area instrument ASPS-2460 American Micro Instruments liquid chromatograph LC-2030C Agilent

[0052] The wetting time, thickening efficiency, transparency, ion resistance, and specific surface area in this invention are tested using the following methods:

[0053] Wetting time test method: Add 198g of deionized water to a 300ml plastic straight bottle with a diameter of 8cm. Weigh 2g of the carbomer polymer of this invention on weighing paper and quickly and evenly spread it on the water surface of the straight bottle. Start the stopwatch and stop the timing when the white particles on the water surface disappear. The time taken is the wetting time.

[0054] Thickening efficiency test method: Add 198g of deionized water to a 300ml, 8cm diameter plastic straight-sided bottle, then add 2g of the carbomer polymer of this invention, and let it stand for 8 hours to fully absorb water and swell. Place a stirrer in the bottle, start stirring, and slowly add 18% sodium hydroxide aqueous solution dropwise. Stir at 800rpm for 40-60min, adjusting the pH value to 7.5±0.2. Place the bottle in a constant temperature water bath and let it stand for 8 hours to stabilize. Test its viscosity at 20rpm.

[0055] Transparency test method: Place an appropriate amount of the prepared stable sample into a centrifuge tube. Place the centrifuge tube in a centrifuge, set the speed to 5000 rpm, and the centrifugation time to 10 minutes. After centrifugation, carefully transfer the sample into a cuvette (to prevent the introduction of air bubbles). Then place the cuvette into a spectrophotometer for transparency measurement.

[0056] Ion resistance test method: Take 200g of neutralized carbomer gel and put it into a 300ml straight bottle. Add a stirrer and start stirring. Add 2g of sodium chloride solid particles to the gel, stir for 30min, and then keep it at a constant temperature for 2h. Test the viscosity at 20rpm.

[0057] Specific surface area testing method:

[0058] 1) Preparations before startup: Check the pressure of the high-purity nitrogen cylinder connected to the equipment to ensure it is between 0.1-0.15 MPa; ensure that the Dewar flask used for cooling is filled with liquid nitrogen;

[0059] 2) Sample pretreatment: Process and dry the sample, weigh the empty sample vial and the total mass after sample loading, and calculate the sample mass before degassing. Install the sample tube into the instrument's degassing station, and start the degassing program in the ASPS-2460 software for 8 hours.

[0060] 3) Instrument Testing: In the ASPS-2460 software, select the BET surface area analysis method and input the actual mass of the degassed sample. Transfer the degassed sample tube to the analysis station, confirm the analysis parameters, and start the test. After the analysis is complete, view the test report in the software report.

[0061] 4) Shutdown and maintenance: After the experiment, first exit the software, shut down the computer, then turn off the main switch of the instrument, and finally turn off the vacuum pump.

[0062] In practical application examples of the formulation, the required testing items and methods are as follows:

[0063] 1) Thickening efficiency: The same amount of thickener was added to the system, and the viscosity of the system at 20 rpm was examined at 20°C, in units of cp;

[0064] 2) Transparency test: Measured using a Unico 7200 spectrophotometer, 100% is optimal;

[0065] 3) Storage stability: Place the finished paint in a 50℃ oven for 14 days and observe the changes in the appearance of the system; Judgment criteria: good storage stability is 5 points, and poor storage stability is 1 point;

[0066] 4) Suspension test: In the pearlescent shampoo formula, the prepared product is placed in a 45℃ oven and observed the degree of water separation and the amount of sedimentation at the bottom of the bottle every other day. The number of days with obvious sedimentation is recorded. The more days, the better.

[0067] 5) Skin Feel Test: Twenty female subjects aged 20-45 years who regularly use makeup products were selected. Subjects formulated pearlescent shampoos using the products provided in Examples C1-C5 of this invention and Comparative Examples D1 and D2. The subjects evaluated the product's refreshing feel using sensory evaluation criteria as follows:

[0068] It's non-greasy and very refreshing, so I'd give it a 9-10 out of 10.

[0069] A slightly oily texture would be rated 7-8 out of 10.

[0070] Oily texture scores 4-6.

[0071] Those with a noticeably greasy feel will be rated 1-3 points.

[0072] A high degree of slipperiness results in a score of 0.

[0073] Calculate the average score.

[0074] 6) Moisturizing test: In an environment with 40-50% humidity, the subjects applied the product provided in the embodiment of the present invention after cleansing, applying toner and lotion in sequence. After keeping it on for 30 minutes, the humidity of the applied part was tested with a skin moisture meter and the data was recorded.

[0075] Example 1

[0076] A carbomer polymer C1 powder was prepared, and its synthetic formulation is as follows:

[0077]

[0078] The steps for synthesizing powdered carbomer polymer using this formulation are as follows:

[0079] Add 400g cyclohexane and 400g ethyl acetate to a 2000ml four-necked flask equipped with a mechanical stirrer and a nitrogen inlet. Then add 0.45g propylene glycol monostearate, 150g acrylic acid, and 1.5g 1,6-hexanediol dimethacrylate. Mix thoroughly and purge with nitrogen for at least 30 minutes to reduce the oxygen content in the system to 1×10⁻⁶. -7 Below mg / L;

[0080] Add 0.75g of tert-butyl-2-ethylhexyl peroxide, 50g of cyclohexane and 50g of ethyl acetate to a dropping flask, mix well and set aside;

[0081] Heat the four-necked flask to 74°C and start adding the mixture dropwise into the flask. Control the dropping time to 4 hours and keep the flask temperature at 74°C during the dropping process.

[0082] Once the addition is complete, maintain the flask temperature at 74°C and keep the contents of the flask warm to allow it to fully polymerize for another 6 hours.

[0083] When the polymerization time was reached, a sample was taken to test the content of residual acrylic acid in the mixture. The test result was 2.85%, corresponding to a monomer reaction degree of 80%, and the reaction was terminated.

[0084] The obtained suspension was filtered under negative pressure to obtain a white precipitate. The white precipitate was then washed three times with a mixed solvent (cyclohexane: ethyl acetate = 50:50 mass ratio). After each washing, the precipitate was filtered to obtain a white polymer containing solvent. The residual acrylic monomer content of the polymer containing solvent after filtration was tested to be 120 ppm (requirement <1000 ppm).

[0085] The white polymer containing solvent was placed in a vacuum oven, maintained at 95°C, and dried under negative pressure (<10 kPa) for 6 hours to obtain carbomer polymer C1 powder. The test data parameters are shown in the table below.

[0086] Test Project Specific surface area Viscosity / cp transparency / % Total residual solvent <![CDATA[33m 2 / g]]> 64500 97.6 0.22％

[0087] Example 2

[0088] A carbomer polymer C2 powder was prepared, and its synthetic formulation is as follows:

[0089]

[0090]

[0091] The steps for synthesizing powdered carbomer polymer using this formulation are as follows:

[0092] Add 850g of n-hexane and 200g of ethyl acetate to a 2000ml four-necked flask equipped with a mechanical stirrer and a nitrogen inlet, then add 0.18g of [unspecified substance]. FT PE6200, 150g methacrylic acid, and 0.9g trimethylolpropane triacrylate were mixed thoroughly and purged with nitrogen for at least 30 minutes to reduce the oxygen content in the system to 1×10⁻⁶. -7 Below mg / L;

[0093] Add 0.9g of dodecyl peroxide, 50g of n-hexane and 25g of ethyl acetate to a dropping flask, mix well and set aside;

[0094] Heat the four-necked flask to 65°C and start adding the mixture dropwise to the flask. Control the dropping time for 2 hours and keep the flask temperature at 65°C during the dropping process.

[0095] Once the addition is complete, maintain the flask temperature at 65°C and keep the contents of the flask warm to allow it to fully polymerize for another 12 hours.

[0096] When the polymerization time was reached, a sample was taken to test the content of residual acrylic acid in the mixture. The test result was 1.41%, corresponding to a monomer reaction degree of 88%, and the reaction was terminated.

[0097] The obtained suspension was filtered under negative pressure to obtain a white precipitate. The white precipitate was then washed three times with a mixed solvent (n-hexane: ethyl acetate = 80:20 mass ratio). After each washing, the precipitate was filtered to obtain a white polymer containing solvent. The residual acrylic monomer content of the polymer containing solvent after filtration was tested to be 135 ppm (requirement <1000 ppm).

[0098] The white polymer containing solvent was placed in a vacuum oven, and dried under negative pressure (<10 kPa) for 7 hours to obtain carbomer polymer C2 powder. The test data parameters are shown in the table below.

[0099] Test Project Specific surface area Viscosity / cp transparency / % Total residual solvent <![CDATA[16m 2 / g]]> 63270 97.3 0.16％

[0100] Example 3

[0101] A carbomer polymer C3 in powder form was prepared, and its synthetic formulation is as follows:

[0102]

[0103] The steps for synthesizing powdered carbomer polymer using this formulation are as follows:

[0104] Add 250g cyclohexane and 375g butyl acetate to a 2000ml four-necked flask equipped with a mechanical stirrer and a nitrogen inlet. Then add 0.855g glyceryl monostearate, 150g acrylic acid, and 3.6g pentaerythritol triallyl ether. Mix thoroughly and purge with nitrogen for at least 30 minutes to reduce the oxygen content in the system to 1×10⁻⁶. -7 Below mg / L;

[0105] Add 0.09g of di(2-ethylhexyl) perdicarbonate, 20g of cyclohexane and 30g of butyl acetate to a dropping flask, mix well and set aside;

[0106] The temperature of the four-necked flask was raised to 43°C, and the mixture was started to be added dropwise to the four-necked flask. The addition time was controlled at 4 hours, and the temperature of the flask was controlled at 43°C during the addition process.

[0107] Once the addition is complete, maintain the flask temperature at 43°C and keep the contents of the flask warm to allow it to fully polymerize for another 10 hours.

[0108] When the polymerization time was reached, a sample was taken to test the content of residual acrylic acid in the mixture. The test result was 4.52%, corresponding to a monomer reaction degree of 75%, and the reaction was terminated.

[0109] The obtained suspension was filtered under negative pressure to obtain a white precipitate. The white precipitate was then washed three times with a mixed solvent (cyclohexane: butyl acetate = 40:60 mass ratio). After each washing, the precipitate was filtered to obtain a white polymer containing solvent. The residual acrylic monomer content of the polymer containing solvent after filtration was tested to be 118 ppm (requirement <1000 ppm).

[0110] The white polymer containing solvent was placed in a vacuum oven and dried under negative pressure (<10 kPa) for 8 hours to obtain carbomer polymer C3 powder. The test data parameters are shown in the table below.

[0111] Test Project Specific surface area Viscosity / cp transparency / % Total residual solvent <![CDATA[46m 2 / g]]> 68650 96.8 0.08％

[0112] Example 4

[0113] A carbomer polymer C4 powder was prepared, and its synthetic formulation is as follows:

[0114]

[0115] The steps for synthesizing powdered carbomer polymer using this formulation are as follows:

[0116] Add 242.5g of n-heptane and 737.5g of ethyl propionate to a 2000ml four-necked flask equipped with a mechanical stirrer and a nitrogen inlet, then add 0.675g of [unspecified ingredient]. PE10100, 150g acrylic acid, and 2.7g trimethylolpropane diallyl ether were mixed thoroughly and purged with nitrogen for at least 30 minutes to reduce the oxygen content in the system to 1×10⁻⁶. -7 Below mg / L;

[0117] Add 1.14g of azobisisobutyronitrile, 20g of n-heptane and 50g of ethyl propionate to a dropping flask, mix well and set aside;

[0118] Heat the four-necked flask to 58°C and start adding the mixture dropwise into the flask. Control the dropping time for 3 hours and keep the flask temperature at 58°C during the dropping process.

[0119] Once the addition is complete, maintain the flask temperature at 58°C and keep the contents of the flask warm to allow it to polymerize fully for another 2 hours.

[0120] When the polymerization time was reached, a sample was taken to test the content of residual acrylic acid in the mixture. The test result was 2.12%, corresponding to a monomer reaction degree of 83%, and the reaction was terminated.

[0121] The obtained suspension was filtered under negative pressure to obtain a white precipitate. The white precipitate was then washed three times with a mixed solvent (n-heptane: ethyl propionate = 25:75 mass ratio). After each washing, the precipitate was filtered to obtain a white polymer containing solvent. The residual acrylic monomer content of the polymer containing solvent after filtration was tested to be 138 ppm (requirement <1000 ppm).

[0122] The white polymer containing solvent was placed in a vacuum oven, maintained at 95°C, and dried under negative pressure (<10 kPa) for 7 hours to obtain carbomer polymer C4 powder. The test data parameters are shown in the table below.

[0123] Test Project Specific surface area Viscosity / cp transparency / % Total residual solvent <![CDATA[28m 2 / g]]> 67320 97.9 0.31％

[0124] Comparative Example 1

[0125] Compared with Example 1, the only difference is the extent of monomer reaction.

[0126] Once the addition is complete, maintain the flask temperature at 74°C and keep the contents of the flask warm to allow for further polymerization for 3 hours. Test the residual acrylic acid content in the mixture; the result is 6.13%, corresponding to a monomer reaction degree of 65%. The reaction is then terminated.

[0127] The test data parameters for the obtained carbomer powder D1 are shown in the table below:

[0128] Test Project Specific surface area Viscosity / cp transparency / % Total residual solvent <![CDATA[62m 2 / g]]> 46870 92.8 0.18％

[0129] Comparative Example 2

[0130] Compared with Example 1, the only difference is the extent of monomer reaction.

[0131] Once the addition is complete, maintain the flask temperature at 74°C and keep the contents of the flask warm to allow for further polymerization for 10 hours. Test the content of residual acrylic acid in the mixture; the result is 0.57%, corresponding to a monomer reaction degree of 95%. The reaction is then terminated.

[0132] The test data parameters for the obtained carbomer polymer D2 powder are shown in the table below:

[0133] Test Project Specific surface area Viscosity / cp transparency / % Total residual solvent <![CDATA[12m 2 / g]]> 49350 91.6 0.38％

[0134] Application Example 1

[0135] In the field of personal care, a comparison is made between the powdered carbomer polymers C1-C4 synthesized in Examples 1-4 of this invention and Comparative Examples D1 and D2 in the pearlescent shampoo formulation.

[0136]

[0137]

[0138] The steps to make this pearlescent shampoo formula are as follows: Add 30g of deionized water to a 250ml beaker and heat it to 85℃;

[0139] 1) While stirring, add 60g sodium lauryl ether sulfate and 0.3g cocamidopropyl betaine to a beaker and mix until well combined;

[0140] 2) Reduce the temperature of the mixture in the beaker to 60°C, and while stirring, add 0.5g of polyquaternium-10 and 0.02g of mica, and mix well;

[0141] 3) Cool the beaker mixture to room temperature while stirring. Add 0.02g BHT, 0.02g disodium ethylenediaminetetraacetate, 0.5g phenoxyethanol and 0.35g carbomer polymer to the beaker mixture and mix well.

[0142] 4) Homogenize the mixture in the beaker at 20,000 rpm for 30 minutes to ensure a more uniform mixture;

[0143] 5) Slowly add 18% sodium hydroxide solution to the beaker mixture, and change the rotation speed as the viscosity increases to make the mixture neutralized and uniform. Add 4.18g of deionized water and adjust the pH value to 5.2-5.8.

[0144] In this formulation, the powdered carbomer polymers C1-C4 synthesized in the comparative examples and the comparative examples D1 and D2 were compared, and the results are shown in the table below:

[0145] Comparison Products Viscosity / cp Skin feel test Storage stability Suspension / d C1 15680 9 5 21 C2 14850 9 5 21 C3 16230 9 5 20 C4 15960 9 5 23 D1 7600 6 2 6 D2 8130 7 3 9

[0146] As can be seen from the table, the powdered carbomer polymers C1-C4 of this patent invention have excellent viscosity, good stability, good skin feel and suspension effect in pearlescent shampoo formulations, which can meet the actual needs of pearlescent shampoo.

[0147] Example 5

[0148] A carbomer polymer C5 powder was prepared, and its synthetic formulation is as follows:

[0149]

[0150] The steps for synthesizing powdered carbomer polymer using this formulation are as follows:

[0151] Add 424.58g of n-hexane and 359.72g of propyl acetate to a 2000ml four-necked flask equipped with a mechanical stirrer and a nitrogen inlet, then add 0.60g of [unspecified ingredient]. PE3100, 133.5g acrylic acid, 16.5g lauryl methacrylate, and 2.00g trimethylolpropane diallyl ether were mixed thoroughly and purged with nitrogen for at least 30 minutes to reduce the oxygen content in the system to 1×10⁻⁶. -7 Below mg / L;

[0152] Add 0.534g of dodecyl peroxide, 40g of n-hexane and 50g of propyl acetate to a dropping flask, mix well and set aside;

[0153] Heat the four-necked flask to 62°C and start adding the mixture dropwise into the flask. Control the dropping time for 2 hours and keep the flask temperature at 62°C during the dropping process.

[0154] Once the addition is complete, maintain the flask temperature at 62°C and keep the substance inside the flask warm to allow it to fully polymerize for another 8 hours.

[0155] When the polymerization time was reached, a sample was taken to test the residual content of acrylic acid and lauryl methacrylate in the mixture. The test result was 2.64%, corresponding to a monomer reaction degree of 82%, and the reaction was terminated.

[0156] The obtained suspension was filtered under negative pressure to obtain a white precipitate. The white precipitate was then washed three times with a mixed solvent (hexane: propyl acetate = 60:40 mass ratio). After each washing, the precipitate was filtered to obtain a white polymer containing solvent. The residual acrylic monomer content of the polymer containing solvent after filtration was tested to be 101 ppm (requirement <1000 ppm).

[0157] The white polymer containing solvent was placed in a vacuum oven, and dried under negative pressure (<10 kPa) for 7 hours to obtain carbomer polymer C5 powder. The test data parameters are shown in the table below.

[0158] Test Project Specific surface area Wetting time Viscosity / cp transparency / % Ion resistance Total residual solvent <![CDATA[36m 2 / g]]> 3’22” 71850 98.8 15667 0.17％

[0159] Example 6

[0160] A carbomer polymer C6 powder was prepared, and its synthetic formulation is as follows:

[0161]

[0162] The steps for synthesizing powdered carbomer polymer using this formulation are as follows:

[0163] Add 386g of n-decane and 109g of ethyl acetate to a 2000ml four-necked flask equipped with a mechanical stirrer and a nitrogen inlet. Then add 0.1419g of sorbitan monooleate, 129g of methacrylic acid, 21g of isooctyl acrylate, and 0.7095g of pentaerythritol diallyl ether. Mix thoroughly and purge with nitrogen for at least 30 minutes to reduce the oxygen content in the system to 1×10⁻⁶. - 7 Below mg / L;

[0164] Add 0.0903g of azobisisobutyronitrile, 30g of n-decane and 30g of ethyl acetate to a dropping flask, mix well and set aside;

[0165] Heat the four-necked flask to 55°C and start adding the mixture dropwise into the flask. Control the dropping time for 2 hours and keep the flask temperature at 55°C during the dropping process.

[0166] Once the addition is complete, maintain the flask temperature at 55°C and keep the contents of the flask warm to allow it to fully polymerize for another 3 hours.

[0167] When the polymerization time was reached, the content of residual acrylic acid and isooctyl acrylate in the mixture was sampled and tested. The test result was 4.15%, corresponding to a monomer reaction degree of 78%, and the reaction was terminated.

[0168] The obtained suspension was filtered under negative pressure to obtain a white precipitate. The white precipitate was then washed three times with a mixed solvent (n-decane: ethyl acetate = 75:25 mass ratio). After each washing, the precipitate was filtered to obtain a white polymer containing solvent. The residual acrylic monomer content of the polymer containing solvent after filtration was tested to be 155 ppm (requirement <1000 ppm).

[0169] The white polymer containing solvent was placed in a vacuum oven and dried under negative pressure (<10 kPa) for 8 hours to obtain carbomer polymer C6 powder. The test data parameters are shown in the table below.

[0170] Test Project Specific surface area Wetting time Viscosity / cp transparency / % Ion resistance Total residual solvent <![CDATA[47m 2 / g]]> 2’56” 68960 98.3 16780 0.09％

[0171] Example 7

[0172] A carbomer polymer C7 powder was prepared, and its synthetic formulation is as follows:

[0173]

[0174] The steps for synthesizing powdered carbomer polymer using this formulation are as follows:

[0175] Add 360g cyclohexane and 540g butyl acetate to a 2000ml four-necked flask equipped with a mechanical stirrer and a nitrogen inlet. Then add 0.5292g diethylene glycol monostearate, 147g methacrylic acid, 3g octadecyl methacrylate, and 3.497g neopentyl glycol dimethacrylate. Mix thoroughly and purge with nitrogen for at least 30 minutes to reduce the oxygen content in the system to 1×10⁻⁶. -7 Below mg / L;

[0176] Add 1.1319g of benzoyl peroxide, 40g of cyclohexane and 60g of butyl acetate to a dropping flask, mix well and set aside;

[0177] The temperature of the four-necked flask was raised to 71°C, and the mixture was started to be added dropwise to the four-necked flask. The addition time was controlled at 4 hours, and the temperature of the flask was controlled at 71°C during the addition process.

[0178] Once the addition is complete, maintain the flask temperature at 71°C and keep the contents of the flask warm to allow it to fully polymerize for another 8 hours.

[0179] When the polymerization time was reached, the content of residual acrylic acid and octadecyl methacrylate in the mixture was sampled and tested. The test result was 1.91%, corresponding to a monomer reaction degree of 85%, and the reaction was terminated.

[0180] The obtained suspension was filtered under negative pressure to obtain a white precipitate. The white precipitate was then washed three times with a mixed solvent (cyclohexane: butyl acetate = 40:60 mass ratio). After each washing, the precipitate was filtered to obtain a white polymer containing solvent. The residual acrylic monomer content of the polymer containing solvent after filtration was tested to be 96 ppm (requirement <1000 ppm).

[0181] The white polymer containing solvent was placed in a vacuum oven, maintained at 95°C, and dried under negative pressure (<10 kPa) for 6 hours to obtain carbomer polymer C7 powder. The test data parameters are shown in the table below.

[0182]

[0183]

[0184] Example 8

[0185] A powdered carbomer polymer C8 was prepared, and its synthetic formulation is as follows:

[0186]

[0187] The steps for synthesizing powdered carbomer polymer using this formulation are as follows:

[0188] Add 238.5g of n-heptane and 745.5g of ethyl propionate to a 2000ml four-necked flask equipped with a mechanical stirrer and a nitrogen inlet, then add 0.795g of [unspecified ingredient]. RPE1720, 139.5g acrylic acid, 10.5g cetyl methacrylate, and 1.3392g trimethylolpropane trimethacrylate were mixed thoroughly and purged with nitrogen for at least 30 minutes to reduce the oxygen content in the system to 1×10⁻⁶. -7 Below mg / L;

[0189] Add 0.7673g of tert-butyl-2-ethylhexyl peroxide, 30g of n-heptane and 60g of ethyl propionate to a dropping flask, mix well and set aside;

[0190] Heat the four-necked flask to 75°C and start adding the mixture dropwise to the flask. Control the dropping time to 4 hours and keep the flask temperature at 75°C during the dropping process.

[0191] Once the addition is complete, maintain the flask temperature at 75°C and keep the contents of the flask warm to allow it to fully polymerize for another 15 hours.

[0192] When the polymerization time was reached, a sample was taken to test the residual content of acrylic acid and cetyl methacrylate in the mixture. The test result was 1.38%, corresponding to a monomer reaction degree of 88%, and the reaction was terminated.

[0193] The obtained suspension was filtered under negative pressure to obtain a white precipitate. The white precipitate was then washed three times with a mixed solvent (n-heptane: ethyl propionate = 25:75 mass ratio). After each washing, the precipitate was filtered to obtain a white polymer containing solvent. The residual acrylic monomer content of the polymer containing solvent after filtration was tested to be 103 ppm (requirement <1000 ppm).

[0194] The white polymer containing solvent was placed in a vacuum oven, and dried under negative pressure (<10 kPa) for 8 hours to obtain carbomer polymer C8 powder. The test data parameters are shown in the table below.

[0195] Test Project Specific surface area Wetting time Viscosity / cp transparency / % Ion resistance Total residual solvent <![CDATA[26m 2 / g]]> 2’47” 72230 98.0 16120 0.15％

[0196] Comparative Example 3

[0197] Compared with Example 5, the only difference lies in the degree of monomer reaction. After the addition was completed, the flask temperature was maintained at 62°C, and the substance in the flask was kept warm to allow it to fully polymerize for another 2 hours. The content of residual acrylic acid in the mixture was then tested, and the result was 6.16%, corresponding to a monomer reaction degree of 70%. The reaction was then terminated.

[0198] The test data parameters for the obtained carbomer powder D3 are shown in the table below:

[0199] Test Project Specific surface area Wetting time Viscosity / cp transparency / % Ion resistance Total residual solvent <![CDATA[68m 2 / g]]> 7’55” 46870 93.1 7860 0.13％

[0200] Comparative Example 4

[0201] Compared with Example 5, the only difference lies in the degree of monomer reaction. After the addition was completed, the flask temperature was maintained at 62°C, and the substance in the flask was kept warm to allow it to polymerize fully for another 12 hours. The content of residual acrylic acid in the mixture was then tested, and the result was 0.44%, corresponding to a monomer reaction degree of 93%. The reaction was then terminated.

[0202] The test data parameters for the obtained carbomer polymer D3 powder are shown in the table below:

[0203] Test Project Specific surface area Wetting time Viscosity / cp transparency / % Ion resistance Total residual solvent <![CDATA[11m 2 / g]]> 12’32” 44120 91.7 6550 0.12％

[0204] Application Example 2

[0205] In skin mask formulations, the powdered carbomer polymers C5-C8 synthesized in this invention were compared with comparative examples D3 and D4.

[0206] raw material illustrate mass / g 1 Deionized water 59.96 3 Carbomer polymers Thickener 0.2 4 Triethanolamine Neutralizing agent 0.54 5 glycerin Moisturizer 0.6 6 Butylene glycol Moisturizer 1.2 7 polydimethylsiloxane emulsifier 5 8 PEG-10-dimethylsiloxane emulsifier 1 9 Polyurethane-35 & Polyurethane-11 Film-forming agent 30 10 Kaolin additive 1 11 EDTA-2Na Chelating agents 0.1 12 Phenoxyethanol & Octylglycol bactericide 0.4 total 100

[0207] The steps to make this skin mask are as follows:

[0208] 1) Add 59.96g of deionized water to a 250ml beaker and heat it to 70℃;

[0209] 2) While stirring, add 5g of polydimethylsiloxane and 1g of PEG-10-dimethylsiloxane to the beaker and wait for them to mix evenly;

[0210] 3) Reduce the temperature of the mixture in the beaker to 50°C, and while stirring, add 1.2g butanediol, 0.6g glycerol, 1g kaolin and 0.2g carbomer polymer and mix well;

[0211] 4) Cool the beaker mixture to room temperature and homogenize it using a homogenizer at 20,000 rpm for 30 minutes to ensure a more uniform mixture.

[0212] 5) While stirring, slowly add 30g of polyurethane-35 & polyurethane-11, 0.1g of EDTA-2Na, and 0.4g of phenoxyethanol & octyl glycol to the mixture in the beaker. Mix thoroughly, then add 0.54g of triethanolamine by metering. As the viscosity increases, adjust the stirring speed to ensure the mixture is neutralized and homogeneous.

[0213] Wait until the pH value is adjusted to 5.2-5.5.

[0214] In this formulation, the powdered carbomer polymers C5-C8 synthesized in the comparative examples and comparative examples D3 and D4 were compared, and the results are shown in the table below:

[0215] Comparison Products Wetting time Viscosity / cp transparency / % Storage stability Moisturizing C5 3’18” 18670 83 5 64％ C6 3’35” 17940 85 5 60％ C7 2’57” 18850 82 5 62％ C8 3’42” 19100 80 5 67％ D3 9’33” 10230 57 2 32％ D4 15’22” 8910 43 3 28％

[0216] As can be seen from the table, the powdered carbomer polymers C5-C8 of this patent invention, compared with comparative examples D3 and D4, exhibit rapid wetting, excellent viscosity and transparency, and good stability in skin mask formulations, thus meeting practical needs.

[0217] The above embodiments are preferred implementations of the present invention, but the present invention is not limited to the above implementations. Any changes, modifications, simplifications, or substitutions made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A method for preparing powdered carbomer polymer, characterized in that, The powdered carbomer is obtained by polymerizing acrylate monomers containing unsaturated double bonds in a solvent in the presence of a crosslinking agent and a free radical initiator. The acrylate monomer containing unsaturated double bonds does not react completely. Preferably, compared with the theoretical amount of 100% complete reaction of the acrylate monomer containing unsaturated double bonds, the degree of reaction of the acrylate monomer containing unsaturated double bonds is 60-95%, and more preferably 75-90%.

2. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: I. Add raw materials containing acrylate monomers with unsaturated double bonds and crosslinking agents to the solvent and mix; II. Heat the mixture, add a free radical initiator to carry out the polymerization reaction, filter and separate the product, wash and dry it to obtain carbomer powder.

3. The preparation method according to claim 1 or 2, characterized in that, Add stabilizers to I; And / or, the solvent in I is selected from alkanes having 1 to 10 carbon atoms, and / or alkyl acetates or alkyl propionates having 1 to 4 carbon atoms; wherein, preferably, the alkanes include one or more of n-hexane, cyclohexane, n-heptane, cycloheptane, and n-decane, and preferably, the alkyl acetates include one or more of ethyl acetate, butyl acetate, ethyl propionate, and butyl propionate; Preferably, the solvent is 4-8 times the total mass of the acrylate monomers containing unsaturated double bonds.

4. The preparation method according to claim 1 or 2, characterized in that, In step II, the polymerization temperature is 40-80℃ and the polymerization time is 4-20h; And / or, in II, the drying temperature is 95-105℃, the vacuum degree is <-10bar, and the drying time is 6-8h.

5. A powdered carbomer polymer, said polymer being prepared by the preparation method according to any one of claims 1-4, characterized in that, The polymer raw materials include acrylate monomers containing unsaturated double bonds, crosslinking agents, free radical initiators, and optional stabilizers.

6. The polymer according to claim 5, characterized in that, The acrylate monomer containing unsaturated double bonds comprises unsaturated carboxylic acids containing double bonds, preferably one or more of acrylic acid, methacrylic acid, maleic acid, cinnamic acid, itaconic acid, fumaric acid, crotonic acid, and aconitic acid. Preferably, the proportion of unsaturated carboxylic acids containing double bonds is 85-100 wt%, based on acrylate monomers containing unsaturated double bonds; And / or, the acrylate monomer containing an unsaturated double bond comprises a hydrophobic monomer with 11-22 carbon atoms containing one unsaturated double bond, having the following general formula: Wherein, R1 is hydrogen or methyl, and R2 is an alkyl structure containing 8-18 carbon atoms; Preferably, the proportion of hydrophobic monomers with 11-22 carbon atoms and containing one unsaturated double bond is 0-15 wt%, based on acrylate monomers containing unsaturated double bonds.

7. The polymer according to claim 5, characterized in that, The crosslinking agent is at least one substance containing at least two unsaturated carbon-carbon double bonds, preferably a polyfunctional acrylate with at least two polymerizable olefinic unsaturated double bonds, and / or a polychain alkenyl polyether with at least two polymerizable olefinic unsaturated double bonds, more preferably the polyfunctional acrylate and polychain alkenyl polyether are formed by esterification or etherification of linear and / or branched polyols. Preferably, the amount of crosslinking agent is 0.01-5 wt% of the total mass of the acrylate monomers with unsaturated double bonds, more preferably 0.1-3 wt%, and more preferably 0.5-2.5 wt%. And / or, the free radical initiator is one or more of organic peroxide compounds, azo compounds, inorganic persulfate compounds and hydrogen peroxide, preferably one or more of azobisisobutyronitrile, tert-butyl-2-ethylhexyl peroxide, di(2-ethylhexyl) percarbonate, benzoyl peroxide, dodecyl peroxide, ammonium persulfate, sodium persulfate and hydrogen peroxide; Preferably, the amount of free radical initiator is 0.02-2 wt% of the total mass of the acrylate monomers with unsaturated double bonds, more preferably 0.05-0.8 wt%. And / or, the stabilizer is a nonionic emulsifier and / or an EO-PO copolymer block polyether; wherein, the nonionic emulsifier preferably comprises a nonionic emulsifier with an HLB value of 1.6-5.6, more preferably one or more of sorbitan trioleate, propylene glycol monostearate, sorbitan monooleate, diethylene glycol monostearate, and glyceryl monostearate; wherein, the EO-PO copolymer block polyether stabilizer preferably has a polyether structure with an EO content of less than 20%; Preferably, the amount of stabilizer used is 0.05-2 wt% of the total mass of the acrylate monomers with unsaturated double bonds, more preferably 0.1-0.6 wt%.

8. The polymer according to claim 5, characterized in that, The powder particles of the carbomer polymer have a specific surface area of ​​15-50 square meters per gram.

9. An application of a powdered carbomer polymer, wherein the polymer is prepared by any one of claims 1-4, or is any one of claims 5-8, and the powdered carbomer polymer is preferred for use as a thickener for transparent gel media in the field of personal care.

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