A carbomer and a method for preparing the same, a gel medium thickener

Abstract

The present application provides a carbomer and a preparation method thereof, and a gel medium thickener, the carbomer comprising a core-shell polymer, the core-shell polymer comprising a core polymer and a shell polymer at least partially covering the core polymer; the core polymer is polymerized from a first monomer mixture; the shell polymer is polymerized from a second monomer mixture; the first monomer mixture comprises an unsaturated carboxylic acid and a first hydrophobic monomer; the second monomer mixture comprises an unsaturated carboxylic acid salt and a second hydrophobic monomer; in the second monomer mixture, the mass ratio of the unsaturated carboxylic acid salt and the second hydrophobic monomer is 6-15:1. The carbomer provided by the present application has the advantages of high infiltration rate, good ion resistance, high transparency, and ideal viscosity obtained by adding a small amount in a formula system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high molecular materials, in particular to a carbomer, a preparation method thereof and a gel medium thickener. BACKGROUND

[0002] Rheology modifiers, also known as thickeners or viscosifiers, are a class of chemicals used to increase the viscosity of liquid or semi-solid systems, and are widely used in various commercial formulations, such as personal care formulations, healthcare formulations, agricultural formulations, paint formulations, laundry and fabric care formulations, and industrial and institutional cleaning formulations.

[0003] Carbomer is a very important rheology modifier, which is a high molecular weight polymer belonging to alkali-swellable acrylic thickener or hydrophobically modified alkali-swellable acrylic thickener in structure. The neutralized carbomer is an excellent gel matrix with excellent thickening, suspending and emulsifying effects, and good compatibility with other excipients. It is widely used as an adhesive, a pharmaceutical excipient and a nutritional additive, especially widely used in emulsions, creams and gels.

[0004] However, the existing carbomer has defects such as poor wetting time, poor thickening efficiency, poor ion resistance or poor transparency. SUMMARY

[0005] The present application provides a carbomer, which has the advantages of fast wetting rate, good ion resistance, high transparency and high thickening efficiency.

[0006] The present application also provides a preparation method of the carbomer, which can prepare the above-mentioned carbomer and has a simple process flow.

[0007] The present application also provides a gel medium thickener, which has the advantages of high wetting rate, good ion resistance, high transparency and high viscosity due to the inclusion of the above-mentioned carbomer.

[0008] In a first aspect, the present application provides a carbomer, which comprises a core-shell polymer, the core-shell polymer comprising a core polymer and a shell polymer at least partially covering the core polymer; the core polymer is polymerized from a first monomer mixture; the shell polymer is polymerized from a second monomer mixture; the first monomer mixture comprises an unsaturated carboxylic acid, a crosslinking agent and a first hydrophobic monomer; the second monomer mixture comprises an unsaturated carboxylic acid salt and a second hydrophobic monomer; in the second monomer mixture, the mass ratio of the unsaturated carboxylic acid salt to the second hydrophobic monomer is 6-15:1.

[0009] Further, in the second monomer mixture, the mass ratio of the unsaturated carboxylic acid salt to the second hydrophobic monomer is 8-12:1.

[0010] Further, the mass ratio of the unsaturated carboxylic acid and the first hydrophobic monomer in the first monomer mixture is 15-50:1.

[0011] Further, the first hydrophobic monomer and the second hydrophobic monomer have a general structure shown in Formula 1:

[0012]

[0013] wherein, R1 is hydrogen or methyl, and R2 is an alkyl structure containing 12-20 carbon atoms.

[0014] Further, the shell polymer accounts for 6-14% of the mass fraction of the core-shell polymer.

[0015] Further, the unsaturated carboxylic acid salt is a monovalent metal salt of the unsaturated carboxylic acid.

[0016] Further, the unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, maleic acid, cinnamic acid, itaconic acid, fumaric acid, crotonic acid, and aconitic acid.

[0017] Further, the anion part of the unsaturated carboxylic acid salt is at least one of acrylic acid anion, methacrylic acid anion, maleic acid anion, cinnamic acid anion, itaconic acid anion, fumaric acid anion, crotonic acid anion, and aconitic acid anion.

[0018] Further, the crosslinking agent contains at least two unsaturated carbon-carbon double bonds.

[0019] Further, the crosslinking agent is a multifunctional acrylate containing at least two polymerizable olefinic unsaturated double bonds, and / or a polyalkenyl polyether containing at least two polymerizable olefinic unsaturated double bonds.

[0020] Further, the mass of the crosslinking agent is 0.01-5% of the total mass of the first monomer mixture.

[0021] In a second aspect, the present application provides a preparation method of the above-mentioned carbomer, comprising the following steps:

[0022] 1) a mixed system comprising a first monomer mixture, a solvent, a crosslinking agent, and a free radical initiator, is subjected to a first polymerization reaction to obtain a material system comprising a core polymer;

[0023] 2) the material system comprising the core polymer is mixed with a second monomer mixture and a free radical initiator, and subjected to a second polymerization reaction to obtain the carbomer.

[0024] Further, the mixed system further comprises a stabilizer; the HLB value of the stabilizer is 2.0-5.6; and / or, the reaction temperature value of the primary polymerization reaction and the secondary polymerization reaction is respectively 52-80℃.

[0025] In a third aspect, the present application provides a gel medium thickener, comprising the carbomer of the first aspect, or the carbomer prepared by the preparation method of the second aspect.

[0026] The carbomer provided by the present application comprises a core-shell polymer, wherein the shell polymer can make the carbomer quickly surface wet when added into water, and improve the ion resistance of the carbomer; the core polymer provides water absorption channels in the internal structure of the carbomer, so that water molecules can quickly enter; the core-shell polymer cooperates with each other to quickly establish a three-dimensional network structure in the application system, bind the movement of free molecules in the system, and comprehensively improve the infiltration rate, viscosity and transparency of the product; in addition, a small amount of the product is added into a formula system to obtain ideal viscosity. DETAILED DESCRIPTION

[0027] In order to make the person skilled in the art better understand the scheme of the present application, the present application is further described in detail below. The following specific embodiments are only used to describe the principles and characteristics of the present application, and the examples are used to explain the present application, but not to limit the scope of the present application. Based on the embodiments of the present application, all other embodiments obtained by the person skilled in the art without creative labor are within the scope of protection of the present application.

[0028] In a first aspect, the present application provides a carbomer, comprising a core-shell polymer, wherein the core-shell polymer comprises a core polymer and a shell polymer at least partially covering the core polymer; the core polymer is polymerized from a first monomer mixture; the shell polymer is polymerized from a second monomer mixture; the first monomer mixture comprises an unsaturated carboxylic acid, a crosslinking agent and a first hydrophobic monomer; the second monomer mixture comprises an unsaturated carboxylic acid salt and a second hydrophobic monomer; and the mass ratio of the unsaturated carboxylic acid salt and the second hydrophobic monomer in the second monomer mixture is 6-15:1.

[0029] The carbomer provided by the present application comprises a core-shell polymer with a specific composition, wherein the shell polymer contains a proper amount of carboxylic acid anions, which are easy to hydrate with the surrounding water molecules through hydrogen bonds when added to water, and make the shell polymer molecular chain swell and stretch, and at the same time, the surrounding water molecules quickly enter the polymer structure, so as to achieve the purpose of rapid wetting; the carboxylic acid in the core-shell polymer can be fully swollen after neutralization with an alkaline substance due to the charge repulsion principle of the carboxylic acid structure, so that the polymer molecular chain can greatly stretch, thereby effectively filling the system volume, quickly establishing a three-dimensional network structure in the application system, binding the movement of free molecules in the system, and achieving the increase of the viscosity of the system and the requirements of the rheological properties; at the same time, part of the hydrophobic monomers in the polymer main chain can associate in water due to the hydrophilic and hydrophobic properties, so that the volume filling of the performance is further 'firm', thereby greatly improving the viscosity and transparency of the system. At the same time, after the carbomer is added with part of salt, the charge repulsion of the carboxylate on the main chain of the carbomer is reduced, so that the main chain shrinks, and the whole carbomer structure begins to 'collapse', but the second hydrophobic monomer matched in the shell polymer can effectively hydrophobically associate in the shrinkage process, prevent the further shrinkage of the carbomer structure, and further improve the viscosity of the system after the addition of salt, so as to improve the ion resistance of the carbomer and the transparency after the addition of salt.

[0030] In addition, in the present application, the second monomer mixture comprises an unsaturated carboxylic acid salt and a second hydrophobic monomer; when the mass ratio of the unsaturated carboxylic acid salt and the second hydrophobic monomer in the second monomer mixture is 6-15:1, the carbomer can further have good wettability, viscosity, transparency and ion resistance; when the mass ratio of the unsaturated carboxylic acid salt and the second hydrophobic monomer is less than 6:1, the product has greater surface hydrophobicity and lower surface tension, it is difficult to wet and absorb water, and the product cannot absorb water; when the mass ratio of the unsaturated carboxylic acid salt and the second hydrophobic monomer is higher than 15:1, the shell chain segment is prone to excessive shrinkage after the addition of salt such as sodium chloride in the system, so that the association during shrinkage is greatly weakened, thereby reducing the viscosity of the product after the addition of salt, reducing the ion resistance and transparency of the system, and failing to meet the use requirements.

[0031] The application scene of the above-mentioned carbomer is not particularly limited in the present application, and due to the above advantages, in some embodiments, the carbomer of the present application can be used in face cream, emulsion, gel and skin care products as a thickening agent and emulsion stabilizer to provide smooth texture and good spreadability; in other embodiments, the carbomer of the present application is also used in external drug preparations, gels and ointments as a thickening agent and stabilizer to provide suitable viscosity and stability.

[0032] In the present invention, the ion resistance of the carbomer is reflected in that when a certain amount of monovalent or / and divalent ion salt compounds, such as sodium chloride, potassium chloride, calcium chloride, magnesium chloride, sodium nitrate, potassium nitrate, calcium nitrate and the like, are added to the carbomer thickened aqueous gel system, the viscosity thereof is reduced to more than 20% of the initial viscosity after the addition of the salt compounds.

[0033] In a preferred embodiment, in the second monomer mixture, the mass ratio of the unsaturated carboxylate to the second hydrophobic monomer is 8-12:1.

[0034] The second monomer mixture described above can further ensure the wetting and adsorption of carbomer to water, avoid affecting the wetting effect due to excessive hydrophobic monomers, and can also effectively enhance the association effect of the shell polymer when salt is added, further reducing the structural shrinkage of carbomer.

[0035] Illustratively, the mass ratio of the unsaturated carboxylate to the second hydrophobic monomer is 8:1, 9:1, 10:1, 11:1, 12:1, etc.

[0036] In a preferred embodiment, in the first monomer mixture, the mass ratio of the unsaturated carboxylic acid to the first hydrophobic monomer is 15-50:1.

[0037] The first monomer mixture as described above can ensure that when the carbomer is neutralized and used in the target system, the carbomer molecular chain is effectively stretched to establish a larger three-dimensional structure, thereby further improving the viscosity of the system. At the same time, the first monomer mixture can provide appropriate association of hydrophobic monomers, thereby further improving the viscosity and transparency of the carbomer.

[0038] In order to further improve the ion resistance of carbomer, in a preferred embodiment, the first hydrophobic monomer and the second hydrophobic monomer have the general structure shown in Formula 1:

[0039]

[0040] Wherein, R1 is hydrogen or methyl, and R2 is an alkyl structure containing 12-20 carbon atoms.

[0041] The first hydrophobic monomer and the second hydrophobic monomer as described above can further ensure the viscosity and transparency of carbomer. When the number of carbon atoms contained in R2 is less than 12, its associative effect in the system after the carbomer is stretched is low, and when salt is added to the system, it is difficult to establish a "tight" structure, resulting in insufficient improvement in the system's ion resistance. When the number of carbon atoms contained in R2 is greater than 20, its hydrophobic property is too strong and it will curl itself in the molecular chain, resulting in low transparency of the product.

[0042] It should be noted that the specific structures of the first hydrophobic monomer and the second hydrophobic monomer can be the same or different, and the present application does not make special limitations thereon.

[0043] Exemplarily, the first hydrophobic monomer and the second hydrophobic monomer are each independently one or more of lauryl acrylate, lauryl methacrylate, myristyl acrylate, myristyl methacrylate, cetyl acrylate, cetyl methacrylate, stearyl acrylate, stearyl methacrylate, eicosyl acrylate and eicosyl methacrylate.

[0044] In a preferred embodiment, the shell polymer accounts for 6-14% of the mass fraction of the core-shell polymer.

[0045] The core-shell polymer as described above can further ensure the rapid water absorption and wetting of the carbomer outer layer, improve the wetting effect of the carbomer, and ensure that the association strength of the shell polymer is not too large, so that the carbomer is fully swollen in the system, further improving the thickening viscosity and transparency of the product.

[0046] Exemplarily, the shell polymer accounts for 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or any value or range consisting of any two values thereof of the mass fraction of the core-shell polymer.

[0047] In a preferred embodiment, the unsaturated carboxylic acid salt is a monovalent metal salt of an unsaturated carboxylic acid;

[0048] In a preferred embodiment, the unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, maleic acid, cinnamic acid, itaconic acid, fumaric acid, crotonic acid, aconitic acid;

[0049] and / or the anion part of the unsaturated carboxylic acid salt is at least one of an acrylic acid anion, a methacrylic acid anion, a maleic acid anion, a cinnamic acid anion, an itaconic acid anion, a fumaric acid anion, a crotonic acid anion, an aconitic acid anion.

[0050] The anion part of the unsaturated carboxylic acid salt and the structure of the unsaturated carboxylic acid can be the same or different, and the present application does not make special limitations thereon.

[0051] In some embodiments, the crosslinking agent contains at least two unsaturated carbon-carbon double bonds.

[0052] In some embodiments, the crosslinking agent is a multifunctional acrylate containing at least two polymerizable ethylenically unsaturated double bonds (e.g., a (meth)acrylate compound of a linear or branched polyol having 2-20 carbon atoms) and / or a polyalkenyl polyether containing at least two polymerizable ethylenically unsaturated double bonds (e.g., an etherification product of an allyl alcohol and a linear or branched polyol having 2-15 carbon atoms).

[0053] In the present application, the above crosslinking agent is used to effectively establish a three-dimensional network structure, reduce the free water of the entire carbomer system, and improve the viscosity and stability of the system.

[0054] Exemplarily, the multifunctional acrylate and the polyalkenyl polyether are formed by esterification or etherification of linear and branched polyols; the polyols are selected from one or more of sucrose, pentaerythritol, dipentaerythritol, trimethylolpropane and its dimer, trihydroxyethylpropane and its dimer; the (meth)acrylate compound as the crosslinking agent may, for example, be selected from one or more of ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,6-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trihydroxyethylpropane tri(meth)acrylate, tetrahydroxymethylmethane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, tetrahydroxymethylmethane tetra(meth)acrylate, and pentaerythritol tetra(meth)acrylate; the polyalkenyl polyether as the crosslinking agent includes a polyallyl ether having a functionality of 2-4 per molecule, such as one or more of pentaerythritol diallyl ether, pentaerythritol triallyl ether, pentaerythritol tetraallyl ether, trimethylolpropane diallyl ether, trimethylolpropane triallyl ether, and the like.

[0055] It can be understood that other types of crosslinking agents, such as silicon crosslinking agents, zinc oxide crosslinking agents, divinylbenzene, methylene diacrylamide, and the like, can also be used in the present application.

[0056] In a preferred embodiment, the crosslinking agent has a mass of 0.01-5% of the total mass of the first monomer mixture. Within this range, the amount of crosslinking agent can avoid excessive crosslinking or insufficient crosslinking; as a further preferred, the amount of crosslinking agent is 0.1-3% of the total mass of the first monomer mixture, more preferably 0.5-2.5%.

[0057] In a preferred embodiment, the carbomer is prepared by a method comprising the following processes:

[0058] 1) a mixture system comprising a first monomer mixture, a solvent, a crosslinking agent, and a free radical initiator, and performing a first polymerization reaction to obtain a material system comprising a core polymer;

[0059] 2) mixing the material system comprising the core polymer with a second monomer mixture and a free radical initiator, and performing a second polymerization reaction to obtain the carbomer.

[0060] The solvent used in the above preparation method can be any liquid that can dissolve the monomers and does not have side reactions with the monomers, for example, selected from alkanes having 1 to 10 carbon atoms, alkyl acetates having 1 to 4 carbon atoms in the alkyl group, and mixtures thereof, wherein the hydrocarbons used include but are not limited to n-hexane, cyclohexane, n-heptane, cycloheptane, n-decane, and mixtures thereof; wherein the alkyl acetates used include but are not limited to ethyl acetate, butyl acetate, ethyl propionate, butyl propionate, and mixtures thereof.

[0061] The free radical initiator used in the above preparation method includes but is not limited to one or more of organic peroxide compounds, azo compounds, inorganic persulfate compounds, and hydrogen peroxide; preferably, the free radical initiator is one or more of azobisisobutyronitrile, azobisisoheptyl nitrile, benzoyl peroxide, lauroyl peroxide, ammonium persulfate, sodium persulfate, and hydrogen peroxide.

[0062] Exemplarily, the amount of the above free radical initiator can be 0.05-1 wt% of the total weight of the monomers, preferably 0.2-0.7 wt%, such as 0.1%, 0.4%, 0.6%.

[0063] In a second aspect, the present application provides a preparation method of the above carbomer, comprising the following steps:

[0064] 1) a mixture system comprising a first monomer mixture, a solvent, a crosslinking agent, and a free radical initiator, and performing a first polymerization reaction to obtain a material system comprising a core polymer;

[0065] 2) mixing the material system comprising the core polymer with a second monomer mixture and a free radical initiator, and performing a second polymerization reaction to obtain the carbomer.

[0066] Further, the mixture system further comprises a stabilizer; the HLB value of the stabilizer is 2.0-5.6; and / or, the reaction temperature of the first polymerization reaction and the second polymerization reaction is independently 52-80°C.

[0067] In some embodiments, the total solid content of the first polymerization or the second polymerization in the polymerization system is 15-18%, wherein the calculation method of the solid content is (stabilizer + crosslinking agent + shell layer polymerized monomer + core layer polymerized monomer) / total mass of the polymerization system x 100%.

[0068] The solvent used in the above preparation method can be any liquid that can dissolve the monomer and does not have side reaction with the monomer, for example, selected from alkane having 1 to 10 carbon atoms, alkyl acetate having 1 to 4 carbon atoms in the alkyl group, and mixtures thereof, wherein the hydrocarbons used include but are not limited to n-hexane, cyclohexane, n-heptane, cycloheptane, n-decane, and mixtures thereof; wherein the alkyl acetate used includes but are not limited to methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and mixtures thereof.

[0069] The solvent used in the above preparation method is alkane, alkyl acetate, wherein the alkane and alkyl acetate can be used alone or in mixture, preferably in mixture. When used in mixture, the mass ratio of the alkane solvent and the alkyl acetate is 2:1 to 1:2.

[0070] The free radical initiator used in the above preparation method includes but is not limited to one or more of organic peroxide compound, azo compound, inorganic persulfate compound, and hydrogen peroxide; preferably, the free radical initiator is one or more of azobisisobutyronitrile, azobisisoheptyl nitrile, benzoyl peroxide, lauroyl peroxide, ammonium persulfate, sodium persulfate, and hydrogen peroxide.

[0071] Illustratively, the amount of the free radical initiator used can be 0.05 to 1 wt% of the total weight of the monomers, preferably 0.2 to 0.7 wt%, such as 0.1%, 0.4%, 0.6%.

[0072] The stabilizer includes but is not limited to one or more of sorbitan tristearate (HLB value of 2.1), propylene glycol monostearate (HLB value of 3.4), polyoxyethylene sorbitol 4,5 oleate (HLB value of 3.7), sorbitan monooleate (HLB value of 4.3), propylene glycol monolaurate (HLB value of 4.5), diethylene glycol monostearate (HLB value of 4.7), isomeric tridecyl alcohol polyether-1.5 (HLB value of 5.4), and glyceryl monostearate (HLB value of 5.5).

[0073] Illustratively, the amount of the stabilizer used can be 0.2 to 1.2% of the total mass of the monomers.

[0074] Illustratively, the system including the first monomer mixture, the solvent, and the crosslinking agent is heated to 52 to 80°C, the free radical initiator is added, and the polymerization is carried out to obtain a material system including the core polymer.

[0075] In a third aspect, the present application provides a gel medium thickener including the carbomer of the first aspect or the carbomer prepared by the preparation method of the second aspect.

[0076] For further understanding of the present application, the technical solutions of the present application will be described clearly and completely in the following with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0077] Unless otherwise specified, the reagents involved in the embodiments of the present application are all commercially available products, which can be purchased through commercial channels.

[0078] Some raw materials and information used in the following experiments are shown in Table 1.

[0079] Table 1:

[0080]

[0081]

[0082] The main equipment information used in the following experiments is shown in Table 2.

[0083] Table 2:

[0084] Equipment name Model Manufacturer Vacuum oven DZF 6050 Shanghai Jinghong Stirrer RW20 IKA Viscometer DVRV Bo Li Fei Spectrophotometer Model 7200 Unico Dissolved oxygen tester F4-Standard Mettler Homogenizer T25 IKA Centrifuge H2050 Shanghai Luxiang

[0085] The wetting time, thickening efficiency, transparency, ion resistance and 1% aqueous solution PH value involved in the following test are tested by the following method:

[0086] Wetting time test method: 198g of deionized water is added to a 300ml plastic straight bottle with a diameter of 8cm, 2g of the capromer sample to be tested is weighed on the weighing paper and quickly and evenly spread on the water surface of the straight bottle, the stopwatch is started, and the timing is stopped when the white particles on the water surface disappear, and the time used is the wetting time.

[0087] Viscosity test method: 198g of deionized water is added to a 300ml plastic straight bottle with a diameter of 8cm, 2g of the capromer sample to be tested is added, and it is placed for 8h to fully absorb water and swell. Put in the stirring paddle, start stirring, slowly add 18% sodium hydroxide aqueous solution, stir at 800rpm for 40-60min, adjust the PH value to 7.5±0.2. Put into constant temperature water bath, stand for 8h to stabilize (this sample is the neutralized sample), test its 20rpm viscosity.

[0088] Transparency test method: an appropriate amount of neutralized sample is taken into a centrifuge tube. The centrifuge tube is placed in the centrifuge, and the speed is set to 5000rpm and the centrifugation time is 10min. After centrifugation, the sample is carefully taken out and placed in a cuvette (to prevent air bubbles from being introduced). Then the cuvette is placed in a spectrophotometer for transparency measurement.

[0089] Ion resistance test method: take 200 g of the neutralized sample into a 300 ml straight bottle, put in a stirring paddle, start stirring. Take 2 g of sodium chloride solid particles and add to the gel, stir for 30 min, and then keep constant temperature for 2 h. Test the viscosity at 20 rpm.

[0090] Example 1

[0091] A carbomer polymer C1 was prepared, and the raw material formula composition was as shown in Table 3:

[0092] Table 3:

[0093]

[0094] In this embodiment, the shell polymer accounted for 6% of the mass fraction of the core-shell polymer in the outer layer, and the total solid content of the polymerization raw material system was 15%.

[0095] The ion-resistant carbomer polymer synthesized by using the raw material formula was as follows:

[0096] 1) 270 g of ethyl acetate and 540 g of n-hexane were added to a 3 L four-necked flask equipped with mechanical stirring and nitrogen inlet, then 0.45 g of diethylene glycol monostearate, 2.88 g of lauryl acrylate were added and mixed uniformly, and the system was replaced with nitrogen for more than 30 min to reduce the oxygen content in the system to 1 x 10 -7 mg / L or less;

[0097] 2) 138.12 g of acrylic acid, 3.45 g of 1,6-hexanediol diacrylate, 0.564 g of azobisisobutyronitrile, 20 g of ethyl acetate and 40 g of n-hexane were added to a dropping flask and mixed uniformly for standby;

[0098] 3) The temperature of the four-necked flask was raised to 65°C, and the mixed solution was started to be added dropwise into the four-necked flask, and the dropping time was controlled for 4 h, and the temperature of the flask was controlled between 63-67°C during the dropping process; when the dropping was completed, the temperature of the flask was kept between 64-66°C, and the material in the flask was kept warm for 3 h to allow sufficient polymerization; when the polymerization time reached, the core part of the polymer in the invention was obtained;

[0099] 4) 8.0 g of sodium acrylate, 1.0 g of lauryl acrylate and 0.036 g of azobisisobutyronitrile were added to the polymerization flask, and the temperature in the kettle was kept at 63-67°C for polymerization for 4 h, and then the temperature was lowered to room temperature to obtain a suspension solution of ion-resistant carbomer polymer;

[0100] 5) The obtained suspension solution was filtered by negative pressure to obtain white precipitate, and the white precipitate was washed with mixed solvent (ethyl acetate:n-hexane = 1:2 mass ratio) for 3 times, and each washing was followed by filtration, and finally white polymer containing solvent was obtained;

[0101] The solvent-containing white polymer was placed in a vacuum oven, the oven temperature was kept at 95°C, and the vacuum drying was carried out for 24 hours to obtain the ion-resistant carbomer polymer C1 powder, and the test data parameters are shown in Table 4.

[0102] Table 4:

[0103] Test item Wetting time Viscosity / cp Transparency / % Ion resistance viscosity / cp 4min35s 56000 97.6 14560

[0104] Example 2

[0105] A carbomer polymer C2 was prepared, and the raw material formula composition is as shown in Table 5:

[0106] Table 5:

[0107]

[0108] In this embodiment, the shell polymer accounts for 14% of the mass fraction of the core-shell polymer in the outer layer, and the total solid content of the polymer raw material system is 18%.

[0109] The ion-resistant carbomer polymer synthesized by using the raw material formula has the following steps:

[0110] 1) 389 g of butyl acetate and 389 g of cyclohexane were added to a 3L four-necked flask equipped with mechanical stirring and nitrogen inlet, then 1.62 g of glyceryl monostearate, 8.6 g of methacrylate octadecyl ester were added and mixed uniformly, and the system was replaced with nitrogen for more than 30 min to reduce the oxygen content in the system to 1x10 -7 mg / L or less;

[0111] 2) 146.2 g of methacrylic acid, 2.34 g of trimethylolpropane triacrylate, 0.3096 g of benzoyl peroxide, 30 g of butyl acetate and 30 g of cyclohexane were added to a dropping flask and mixed uniformly for standby;

[0112] 3) The temperature of the four-necked flask was raised to 78°C, and the mixed solution was started to be added dropwise into the four-necked flask, and the dropwise time was controlled for 4 h, and the temperature of the flask was controlled between 76-80°C during the dropwise process; when the dropwise was completed, the temperature of the flask was kept between 77-79°C, and the material in the flask was kept warm for 3 h to allow sufficient polymerization; when the polymerization time reached, the core part of the polymer in this invention was obtained;

[0113] 4) 23.26 g of potassium methacrylate, 1.94 g of methacrylate octadecyl ester and 0.0504 g of benzoyl peroxide were added to the polymerization flask, and the temperature in the kettle was kept at 76-80°C for polymerization for 4 h, and then it was cooled to room temperature to obtain a suspension solution of ion-resistant carbomer polymer;

[0114] 5) The obtained suspension was filtered by negative pressure to obtain white precipitate, and the white precipitate was washed with mixed solvent (butyl acetate: cyclohexane = 1:1 mass ratio) for 3 times, and each time was filtered to obtain white polymer containing solvent;

[0115] The white polymer containing solvent was placed in a vacuum oven, and the oven temperature was kept at 95°C, and the vacuum drying was carried out for 24 hours to obtain ion-resistant carbomer polymer C2 powder, and the test data parameters are shown in Table 6.

[0116] Table 6:

[0117] Test item Wetting time Viscosity / cp Transparency / % Ion resistance viscosity / cp 4min50s 55600 98.2 12800

[0118] Example 3

[0119] A carbomer polymer C3 was prepared, and the raw material formula composition was as shown in Table 7:

[0120] Table 7:

[0121]

[0122] In this embodiment, the shell polymer accounts for 10% of the mass fraction of the core-shell polymer in the outer layer, and the total solid content of the polymerization raw material system is 16%.

[0123] The ion-resistant carbomer polymer synthesized by using the raw material formula has the following steps:

[0124] 1) 526.67 g of propyl acetate and 263.33 g of n-heptane were added to a 3L four-necked flask with mechanical stirring and nitrogen inlet, and then 0.96 g of sorbitan tristearate, 4.8 g of cetyl methacrylate were added and mixed uniformly, and the system was replaced with nitrogen for more than 30 min, and the oxygen content in the system was replaced to 1 x 10 -7 mg / L or less;

[0125] 2) 139.2 g of acrylic acid, 0.96 g of pentaerythritol diallyl ether, 1.008 g of azobis diisopropyl cyanide, 40 g of propyl acetate and 20 g of n-heptane were added to a dropping flask and mixed uniformly for standby;

[0126] 3) The temperature of the four-necked flask was raised to 54°C, and the mixed solution was started to be added to the four-necked flask, and the dropping time was controlled for 4 h, and the temperature of the flask was controlled between 52-56°C during the dropping process; when the dropping was completed, the temperature of the flask was kept between 53-55°C, and the material in the flask was kept for 3 h to fully polymerize; when the polymerization time reached, the core part of the polymer in the invention was obtained;

[0127] 4) To the polymerization bottle, 14.55 g of sodium methacrylate, 1.45 g of cetyl methacrylate and 0.112 g of azobis isobutyronitrile were added, and the temperature in the kettle was maintained at 52-56 °C for 4 h of polymerization, and then the temperature was lowered to room temperature to obtain a suspension solution of the ion-resistant carbomer polymer;

[0128] 5) The obtained suspension solution was filtered by negative pressure to obtain white precipitates, and the white precipitates were washed 3 times with a mixed solvent (propyl acetate: n-heptane = 2:1 by mass), and then filtered each time to obtain white polymers containing solvent;

[0129] The white polymers containing solvent were placed in a vacuum oven, dried at 95 °C under negative pressure for 24 h to obtain ion-resistant carbomer polymer C3 powder, and the test data parameters are shown in Table 8.

[0130] Table 8:

[0131] Test item Wetting time Viscosity / cp Transparency / % Ion resistance viscosity / cp 4min52s 53800 97.7 13200

[0132] Example 4

[0133] A carbomer polymer C4 was prepared, and the raw material formula composition is shown in Table 9:

[0134] Table 9:

[0135]

[0136] In this example, the mass fraction of the shell polymer in the core-shell polymer was 12% in the outer layer, and the total solid content of the polymerization raw material system was 16%.

[0137] The ion-resistant carbomer polymer synthesized by using the raw material formula was prepared by the following steps:

[0138] 1) 402.5 g of methyl acetate and 402.5 g of cyclohexane were added to a 3 L four-necked flask equipped with mechanical stirring and a nitrogen inlet, and then 1.92 g of polyoxyethylene sorbitol 4,5 oleate, 3.91 g of eicosyl acrylate, and 0.5632 g of azobis isobutyronitrile were added, and the mixture was stirred uniformly, and the system was replaced with nitrogen for more than 30 min to reduce the oxygen content in the system to 1 x 10 -7 mg / L or less;

[0139] 2) 136.89 g of methacrylic acid, 2.88 g of trimethylolpropane triacrylate, 0.5632 g of azobis isobutyronitrile, 30 g of methyl acetate and 30 g of cyclohexane were added to a dropping flask, and the mixture was stirred uniformly, and then the system was replaced with nitrogen for more than 30 min to reduce the oxygen content in the system to 1 x 10

[0140] 3) The temperature of the four-necked flask is raised to 63°C, and the mixed solution is started to be added dropwise into the four-necked flask, with the dropwise time controlled to be 4h, and the temperature of the flask is controlled to be between 61-65°C during the dropwise process; when the dropwise is completed, the temperature of the flask is kept to be between 62-64°C, and the substance in the flask is kept to be heated for 3h to make it fully polymerize; when the polymerization time reaches, the core part of the polymer in the invention is obtained;

[0141] 4) 17.28g of sodium acrylate, 1.92g of cetyl methacrylate and 0.0768g of azobis isobutyronitrile are added into the polymerization flask again, the temperature in the kettle is kept to be 61-65°C, and the polymerization is kept for 4h, and then it is reduced to room temperature, and a suspension solution of the ion-resistant carbomer polymer is obtained;

[0142] 5) The obtained suspension solution is filtered by negative pressure to obtain white precipitate, and the white precipitate is washed with mixed solvent (methyl acetate: cyclohexane = 1:1 by mass) for 3 times, and each washing is filtered, and finally the white polymer containing solvent is obtained;

[0143] The white polymer containing solvent is placed into a vacuum oven, the temperature of the oven is kept to be 95°C, and the drying is carried out under negative pressure for 24h, and the ion-resistant carbomer polymer C4 powder is obtained, and the test data parameters are shown in Table 10.

[0144] Table 10:

[0145] Test item Wetting time Viscosity / cp Transparency / % Ion resistance viscosity / cp 4min35s 55800 98.0 15100

[0146] Example 5

[0147] A carbomer polymer C5 is prepared, and the raw material formula composition is shown in Table 11:

[0148] Table 11:

[0149]

[0150] In this embodiment, the mass fraction of the shell polymer in the outer layer of the core-shell polymer is 8%, and the total solid content of the polymerization raw material system is 17%.

[0151] The ion-resistant carbomer polymer synthesized by using the raw material formula is prepared by the following steps:

[0152] 1) 291.6g of ethyl acetate and 452.4g of cyclohexane are added into a four-necked flask with a capacity of 3L which is provided with mechanical stirring and nitrogen inlet, and then 0.8g of glyceryl monostearate and 3.27g of methacrylate octadecyl ester are added, and the mixture is uniformly mixed, and the system is replaced by nitrogen for more than 30min, and the oxygen content in the system is replaced to be less than 1×10 -7 mg / L;

[0153] 2) Put 143.93 g of acrylic acid, 3.84 g of pentaerythritol diallyl ether, 0.8832 g of azobisisoheptanenitrile, 30 g of ethyl acetate and 30 g of cyclohexane into a dropping flask, mix well, and reserve;

[0154] 3) Raise the temperature of the four-necked flask to 54°C, start dropping the mixed solution into the four-necked flask, control the dropping time for 4 h, control the temperature of the flask between 52-56°C during the dropping process; when the dropping is completed, keep the temperature of the flask between 53-55°C, and heat the material in the flask to make it polymerize fully for 3 h; when the polymerization time reaches, the core part of the polymer in this invention is obtained;

[0155] 4) Add 11.02 g of sodium acrylate, 1.78 g of cetyl methacrylate and 0.0768 g of azobisisoheptanenitrile into the polymerization flask again, keep the temperature in the kettle between 52-56°C for polymerization for 4 h, and reduce to room temperature to obtain a suspension solution of ion-resistant carbomer polymer;

[0156] 5) The obtained suspension solution is filtered by negative pressure to obtain white precipitate, and the white precipitate is washed with mixed solvent (ethyl acetate: cyclohexane = 1:1.5 mass ratio) for 3 times, and filtered after each washing, and finally white polymer containing solvent is obtained;

[0157] The white polymer containing solvent is placed in a vacuum oven, dried at 95°C under negative pressure, and dried for 24 hours to obtain ion-resistant carbomer polymer C5 powder, and the test data parameters are shown in Table 12.

[0158] Table 12:

[0159] Test item Wetting time Viscosity / cp Transparency / % Ion resistance viscosity / cp 4min42s 54600 97.9 14900

[0160] Example 6

[0161] A carbomer polymer C6 is prepared, and the raw material formula composition is as shown in Table 13:

[0162] Table 13:

[0163]

[0164] In this embodiment, the mass fraction of the shell polymer in the outer layer of the core-shell polymer is 11%, and the total solid content of the polymerization raw material system is 16.5%.

[0165] The ion-resistant carbomer polymer synthesized by using this raw material formula has the following steps:

[0166] 1) Put 454.17 g of butyl acetate and 315.83 g of n-hexane into a 3L four-necked flask equipped with mechanical stirring and nitrogen inlet, then add 1.6 g of sorbitan tristearate, 6.47 g of lauryl acrylate, mix well, replace the oxygen in the system with nitrogen for more than 30 min, and replace the oxygen content in the system to 1 x 10 -7 mg / L or less;

[0167] 2) Put 135.93 g of acrylic acid, 2.4 g of 1,6-hexanediol diacrylate, 0.7832 g of azobisisobutyronitrile, 30 g of ethyl acetate and 30 g of cyclohexane into a dropping flask, mix well, and reserve;

[0168] 3) Raise the temperature of the four-necked flask to 65°C, start dropping the mixed solution into the four-necked flask, control the dropping time for 4 h, and control the temperature of the flask between 63-67°C during the dropping process; when the dropping is completed, keep the temperature of the flask between 64-66°C, and heat the material in the flask to allow it to polymerize fully for 3 h; when the polymerization time reaches, the core part of the polymer in the invention is obtained;

[0169] 4) Add 16.47 g of potassium methacrylate, 1.13 g of arachidyl acrylate and 0.0968 g of azobisisobutyronitrile to the polymerization flask, keep the temperature in the kettle at 52-56°C for polymerization for 4 h, and cool to room temperature to obtain a suspension solution of ion-resistant carbomer polymer;

[0170] 5) The obtained suspension solution is filtered by negative pressure to obtain white precipitate, and the white precipitate is washed with mixed solvent (butyl acetate:n-hexane = 1.4:1 by mass) for 3 times, and filtered after each washing, and finally a white polymer containing solvent is obtained;

[0171] The white polymer containing solvent is placed in a vacuum oven, dried at 95°C under negative pressure, and dried for 24 hours to obtain ion-resistant carbomer polymer C6 powder, and the test data parameters are shown in Table 14.

[0172] Table 14:

[0173] Test item Wetting time Viscosity / cp Transparency / % Ion resistance viscosity / cp 4min27s 55300 98.2 15500

[0174] Comparative Example 1

[0175] The comparative product D1 with the mass ratio of outer layer unsaturated carboxylate and second hydrophobic monomer of 4:1 is prepared according to the synthesis steps of Example 4, and the raw material formula composition is as shown in Table 15.

[0176] Table 15:

[0177]

[0178] In this embodiment, the shell polymer accounts for 12% of the mass fraction of the core-shell polymer, and the total solid content of the polymer raw material system is 16%.

[0179] The polymerization step was performed according to Example 4 to synthesize comparative polymer D1 powder, and the test data parameters are shown in Table 16 below.

[0180] Table 16:

[0181] Test item Wetting time Viscosity / cp Transparency / % Ion resistance viscosity / cp 25min45s 46800 92.6 9100

[0182] Comparative Example 2

[0183] Comparative product D2 with a mass ratio of unsaturated carboxylate salt and second hydrophobic monomer of 16:1 was prepared according to the synthesis step of Example 4, and the raw material formula composition is as shown in Table 17 below.

[0184] Table 17:

[0185]

[0186] In this embodiment, the shell polymer accounts for 12% of the mass fraction of the core-shell polymer, and the total solid content of the polymer raw material system is 16%.

[0187] The polymerization step was performed according to Example 4 to synthesize comparative polymer D2 powder, and the test data parameters are shown in Table 18 below.

[0188] Table 18:

[0189] Test item Wetting time Viscosity / cp Transparency / % Ion resistance viscosity / cp 4min25s 51800 96.9 5600

[0190] Comparative Example 3

[0191] Comparative product D3 with a mass ratio of unsaturated carboxylate salt and second hydrophobic monomer of 9:1 was prepared according to the synthesis step of Example 4, and the raw material formula composition is as shown in Table 19 below.

[0192] Table 19:

[0193]

[0194] In this embodiment, the total solid content of the polymer raw material system is 16%.

[0195] The polymerization step was performed according to Example 4 to synthesize comparative polymer D3 powder, and the test data parameters are shown in Table 20 below.

[0196] Table 20:

[0197] Test item Wetting time Viscosity / cp Transparency / % Ion resistance viscosity / cp 3min10s 23000 94.5 6100

[0198] Summary: From the above results, it can be seen that Examples 1-6 can ensure that the wetting time of carbomer is shorter, and the viscosity, transparency and ion resistance viscosity are higher by limiting the mass ratio of the shell polymer raw material unsaturated carboxylate and the second hydrophobic monomer to 6 to 15:1, while the carbomer of Comparative Examples 1-3 cannot take into account the wetting time, viscosity, transparency and ion resistance viscosity.

[0199] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbomer, characterized in that The invention comprises a core-shell polymer, wherein the core-shell polymer comprises a core polymer and a shell polymer at least partially covering the core polymer; the core polymer is formed by polymerizing a first monomer mixture; the shell polymer is formed by polymerizing a second monomer mixture; the first monomer mixture comprises an unsaturated carboxylic acid, a cross-linking agent, and a first hydrophobic monomer; the second monomer mixture comprises an unsaturated carboxylate and a second hydrophobic monomer; in the second monomer mixture, the mass ratio of the unsaturated carboxylate to the second hydrophobic monomer is 6-15:1; the first hydrophobic monomer and the second hydrophobic monomer have the general structure shown in Formula 1: Formula 1, Wherein, R1 is hydrogen or methyl, and R2 is an alkyl structure containing 12-20 carbon atoms.

2. Carbomer according to claim 1, characterized in that In the second monomer mixture, the mass ratio of the unsaturated carboxylate and the second hydrophobic monomer is 8-12:1; And / or, in the first monomer mixture, the mass ratio of the unsaturated carboxylic acid to the first hydrophobic monomer is 15-50:

1.

3. Carbomer according to claim 1 or 2, characterized in that The mass fraction of the shell polymer in the core-shell polymer is 6-14%.

4. Carbomer according to claim 1 or 2, characterized in that The unsaturated carboxylate is a monovalent metal salt of an unsaturated carboxylic acid.

5. The carbomer according to claim 4, wherein The unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, maleic acid, cinnamic acid, itaconic acid, fumaric acid, crotonic acid, and aconitic acid.

6. Carbomer according to claim 1 or 2, characterized in that The crosslinking agent contains at least two unsaturated carbon-carbon double bonds.

7. The carbomer according to claim 6, wherein The crosslinking agent is a multifunctional acrylate containing at least two polymerizable ethylenically unsaturated double bonds, and / or a multifunctional alkenyl polyether containing at least two polymerizable ethylenically unsaturated double bonds.

8. The carbomer according to claim 6, wherein The mass of the cross-linking agent is 0.01-5% of the total mass of the first monomer mixture.

9. A method for preparing the carbomer according to any one of claims 1 to 8, comprising the following steps: 1) a mixed system including a first monomer mixture, a solvent, a crosslinking agent, and a free radical initiator is subjected to a polymerization reaction to obtain a material system including a core polymer; 2) The material system including the core polymer is mixed with a second monomer mixture and a free radical initiator to carry out a secondary polymerization reaction to obtain the carbomer.

10. The preparation method according to claim 9, characterized in that The mixed system further includes a stabilizer; the HLB value of the stabilizer is 2.0-5.6; And / or, the reaction temperature of the primary polymerization reaction and the secondary polymerization reaction are independently 52-80°C.

11. A gel medium thickener, characterized in that: The invention relates to a carbomer comprising the carbomer according to any one of claims 1 to 8, or the carbomer prepared by the preparation method according to any one of claims 9 to 10.

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