Three-in-one sodium polyacrylate thickening agent as well as preparation method and application thereof

Abstract

The invention relates to a three-in-one sodium polyacrylate thickening agent as well as a preparation method and application thereof, and belongs to the technical field of thickening agents. The three-in-one sodium polyacrylate thickening agent comprises a copolymer of sodium acrylate and long-chain alkyl alcohol polyoxyethylene ether methacrylate, and a humectant, the long-chain alkyl alcohol polyoxyethylene ether methacrylate comprises a compound of octadecyl to docosyl alkyl alcohol, and the humectant is trehalose and / or hydroxyethyl cellulose. The three-in-one sodium polyacrylate thickening agent has high viscosity, high salt resistance and high moisture retention at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of thickeners, and in particular to a three-in-one sodium polyacrylate thickener and a preparation method and application thereof. Background Art

[0002] Thickener is a rheological additive, which is often used in coatings, pharmaceuticals, printing and dyeing, cosmetics, food additives, oil production, papermaking and leather processing. There are many types of thickeners available on the market. According to their composition and mechanism of action, they are mainly divided into cellulose thickeners, polyacrylic acid thickeners, associative polyurethane thickeners and inorganic thickeners; among them, sodium polyacrylate in polyacrylic acid thickeners is the most widely used. Sodium polyacrylate thickener mainly increases the viscosity of the solution by extending its molecular chain from a spiral to a rod through the like electrostatic repulsion of carboxylate ions, thereby achieving a good thickening effect.

[0003] However, due to the poor salt resistance of sodium polyacrylate thickener, the thickening effect of the thickening object containing electrolyte salts is poor. At present, by copolymerizing active monomers with certain salt resistance (such as nonionic acrylamide, N-vinyl pyrrolidone, etc.) with sodium acrylate, or grafting sulfonic acid groups on the molecular chain of sodium polyacrylate, the salt resistance of sodium polyacrylate can be enhanced to a certain extent and its thickening effect can be improved. In order to further improve the salt resistance of sodium polyacrylate, people began to introduce a small amount of hydrophobic groups on the molecular chain of sodium polyacrylate to form hydrophobic associations to enhance its salt resistance, such as octadecyl methacrylate or hexadecyl methacrylate as hydrophobic monomers and sodium acrylate (hydrophilic monomers) copolymerization, but due to the hydrophobic monomer and hydrophilic monomer can not be fully contacted and the poor water solubility of the copolymer formed by polymerization and cause the salt resistance of this type of thickener to improve limited.

[0004] In addition, the moisturizing ability of sodium polyacrylate thickener is limited. It can only absorb some water through its own hydrophilicity and wrap some water molecules between the sodium acrylate molecular chains. Once it encounters electrolyte salt, the entanglement structure between these sodium acrylate molecular chains will be destroyed, resulting in a significant decrease in the moisturizing performance of sodium polyacrylate. At present, the market requirements for thickeners are: high viscosity (can reduce the dosage), salt resistance (expand its scope of use) and moisturizing (increase its functional diversity), and the existing sodium polyacrylate thickener cannot meet the market demand. Therefore, a three-in-one thickener with high viscosity, salt resistance and moisturizing is urgently needed. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a three-in-one sodium polyacrylate thickener and a preparation method and application thereof, and to develop a multifunctional sodium polyacrylate thickener.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a three-in-one sodium polyacrylate thickener, which comprises a copolymer of sodium acrylate and long-chain alkyl alcohol polyoxyethylene ether methacrylate and a humectant; the humectant is trehalose and / or hydroxyethyl cellulose.

[0008] The invention combines a sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer prepared by polymerization of sodium acrylate and long-chain alkyl alcohol polyoxyethylene ether methacrylate with a specific moisturizer, utilizes the hydrophobic association of the long-chain alkyl group in the long-chain alkyl alcohol polyoxyethylene ether methacrylate and its shielding effect on electrolytes to enhance the viscosity and salt resistance of the thickener, utilizes the hydrophilic group of polyoxyethylene ether to improve the water solubility of the long-chain alkyl alcohol polyoxyethylene ether methacrylate, and enhances the solubility of the thickener in water, thereby significantly giving the thickener high viscosity and high salt resistance; at the same time, trehalose and / or hydroxyethyl cellulose are used as moisturizers, which work synergistically with the sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer, so that the thickener has high viscosity and high salt resistance and excellent moisturizing performance, thereby achieving a "three-in-one" effect of high viscosity, high salt resistance and high moisturizing.

[0009] Moreover, the study found that not all moisturizers can work synergistically with sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer. When conventional moisturizers such as hyaluronic acid, sorbitol, maleic acid chitosan, sodium lactate, xanthan gum or potato pregelatinized starch work together with sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer, although they can also improve the moisturizing properties of the thickener to a certain extent, they will also cause the viscosity and salt resistance of the thickener to drop significantly, making it difficult to have high viscosity, high salt resistance and high moisturizing properties.

[0010] As a preferred embodiment of the three-in-one sodium polyacrylate thickener of the present invention, the mass percentage of the long-chain alkyl alcohol polyoxyethylene ether methacrylate relative to sodium acrylate is 0.5% to 10.0%, preferably 1.0% to 6.0%, specifically 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 10.0% or any two of the range values.

[0011] Optionally, the sodium acrylate can be prepared by diluting acrylic acid from which the polymerization inhibitor has been removed and partially neutralizing it with sodium hydroxide; wherein the degree of neutralization is controlled at 80%±20%, preferably 80%±5%; and the solid content of the sodium acrylate solution is preferably 20% to 45%, further preferably 38%±5%, and more preferably 38%±2%.

[0012] The study found that the content of long-chain alkyl alcohol polyoxyethylene ether methacrylate is the main factor that affects the performance of sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer, which not only affects its solubility, but also affects the thickening effect and salt resistance of the thickener; when the addition amount of long-chain alkyl alcohol polyoxyethylene ether methacrylate relative to sodium acrylate is within the above range, it can not only ensure that the sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer has good solubility, but also give the thickener better thickening effect and salt resistance. Another important factor affecting the performance of sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer is the number of carbon atoms in the alkyl alcohol in the long-chain alkyl alcohol polyoxyethylene ether methacrylate, that is, the length of the carbon chain; with the increase of the number of carbon atoms, the water solubility of the sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer decreases, so the upper limit of its appropriate addition amount can be reduced accordingly according to the actual situation, and the upper limit of the addition amount of alkyl alcohol polyoxyethylene ether methacrylate is reduced by about 10% to 20% for every increase of 2 carbon atoms.

[0013] As a preferred embodiment of the three-in-one sodium polyacrylate thickener of the present invention, the mass percentage of trehalose relative to sodium acrylate is 0.1% to 5.0%, preferably 0.5% to 3.0%, specifically it can be one of or any two of 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%.

[0014] As a preferred embodiment of the three-in-one sodium polyacrylate thickener of the present invention, the mass percentage of hydroxyethyl cellulose relative to sodium acrylate is 0.1% to 4.0%, preferably 0.2% to 2.0%, specifically it can be one of 0.1%, 0.2%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0% or any two of the range values.

[0015] As a preferred embodiment of the three-in-one sodium polyacrylate thickener of the present invention, the number of carbon atoms of the long-chain alkyl group in the long-chain alkyl alcohol polyoxyethylene ether methacrylate is 18 to 22; preferably, the long-chain alkyl alcohol polyoxyethylene ether methacrylate includes at least one of octadecyl polyoxyethylene ether methacrylate, eicosyl polyoxyethylene ether methacrylate, and docosyl polyoxyethylene ether methacrylate.

[0016] The study found that as the number of carbon atoms in the long-chain alkyl group increases, the water solubility of the sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer decreases; and the above-mentioned long-chain alkyl alcohol polyoxyethylene ether methacrylate with a carbon atom number of 18 to 22 can not only make the sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer maintain a high water solubility, but also can better enhance the viscosity and salt resistance of the thickener; a higher number of carbon atoms will reduce its water solubility, while a lower number of carbon atoms will reduce its associative thickening effect.

[0017] In a second aspect, the present invention provides a method for preparing the above-mentioned three-in-one sodium polyacrylate thickener, comprising the following steps: uniformly mixing sodium acrylate, long-chain alkyl alcohol polyoxyethylene ether methacrylate, a humectant, a solvent and a free radical initiator, and causing a free radical polymerization reaction to obtain the three-in-one sodium polyacrylate thickener.

[0018] Preferably, in the above preparation method, UV light curing technology can be used to make each component undergo free radical polymerization reaction under ultraviolet light irradiation; wherein the free radical initiator is an ultraviolet light initiator, and the ultraviolet light initiator is preferably one or more of 1-hydroxy-cyclohexyl-phenyl ketone (184), phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (819), azobisisobutyramidine hydrochloride (V50), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), 2-isopropylthioxanthone (ITX), 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173); the amount of free radical initiator added is a conventional amount (for example, based on the reaction monomer, it is one thousandth to one ten-thousandth of the mass of the reaction monomer). The free radical polymerization reaction specifically involves polymerization under ultraviolet light irradiation for 1 hour; the free radical polymerization reaction refers to the free polymerization of sodium acrylate and long-chain alkyl alcohol polyoxyethylene ether methacrylate to form a sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer, and the moisturizer and solvent do not participate in the reaction, but are contained in the sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer; the free radical polymerization reaction may also be further processed (granulation → drying at 85°C to constant weight → crushing → passing through a sieve of 100 mesh or above) to obtain a white powder.

[0019] In a third aspect, the present invention provides the use of the three-in-one sodium polyacrylate thickener in daily cosmetics, coatings, cement mortar or textiles. In addition, it should be noted that the above application is only part of the application scenarios of the three-in-one sodium polyacrylate thickener of the present invention, and the three-in-one sodium polyacrylate thickener is also suitable for other high-salt thickening systems.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The invention combines a sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer prepared by polymerization of sodium acrylate and long-chain alkyl alcohol polyoxyethylene ether methacrylate with a specific moisturizer, utilizes the hydrophobic association of the long-chain alkyl group in the long-chain alkyl alcohol polyoxyethylene ether methacrylate and its shielding effect on electrolytes to enhance the viscosity and salt resistance of the thickener, utilizes the hydrophilic group of polyoxyethylene ether to improve the water solubility of the long-chain alkyl alcohol polyoxyethylene ether methacrylate, and enhances the solubility of the thickener in water, thereby significantly giving the thickener high viscosity and high salt resistance; meanwhile, trehalose and / or hydroxyethyl cellulose are used as moisturizers to synergize with the sodium acrylate-long-chain alkyl alcohol polyoxyethylene ether methacrylate copolymer, so that the thickener has high viscosity and high salt resistance and excellent moisturizing performance. DETAILED DESCRIPTION

[0022] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0023] Unless otherwise specified, other materials, reagents, etc. used in the examples and comparative examples can be obtained from commercial sources.

[0024] Example 1

[0025] An embodiment of the three-in-one sodium polyacrylate thickener of the present invention, and a preparation method thereof, comprises the following steps:

[0026] S1, 100g of acrylic acid from which the polymerization inhibitor has been removed and 75.8g of pure water are mixed to form an acrylic acid solution, and then 140g of a 32% sodium hydroxide aqueous solution is slowly added dropwise thereto, and the mixture is stirred while being added dropwise, and the system temperature is cooled to be below 40°C, to prepare 315.8g of a sodium acrylate solution having a neutralization degree of 80% and a mass fraction of 38%;

[0027] S2, after evenly mixing 100 g of the sodium acrylate solution in S1, 0.8 g of octadecyl polyoxyethylene ether methacrylate, 0.2 g of humectant trehalose and 0.3 g of a photoinitiator with a mass concentration of 10%, polymerize under high-pressure mercury lamp for 1 hour to obtain a three-in-one sodium polyacrylate thickener.

[0028] Example 2

[0029] An embodiment of the three-in-one sodium polyacrylate thickener of the present invention has a preparation method that is substantially the same as that of embodiment 1, except that the amount of trehalose added as a moisturizing agent in step S2 is 0.5 g.

[0030] Example 3

[0031] An embodiment of the three-in-one sodium polyacrylate thickener of the present invention has a preparation method that is substantially the same as that of embodiment 1, except that the moisturizing agent in step S2 is hydroxyethyl cellulose and the added amount is 0.1 g.

[0032] Example 4

[0033] An embodiment of the three-in-one sodium polyacrylate thickener of the present invention has a preparation method that is substantially the same as that of embodiment 1, except that the moisturizing agent in step S2 is hydroxyethyl cellulose and the added amount is 0.2 g.

[0034] Example 5

[0035] An embodiment of the three-in-one sodium polyacrylate thickener of the present invention has a preparation method that is substantially the same as that of embodiment 1, except that the amount of octadecyl polyoxyethylene ether methacrylate added in step S1 is 0.4 g.

[0036] Example 6

[0037] An embodiment of the sodium polyacrylate thickener of the present invention, the preparation method of the sodium polyacrylate thickener described in this embodiment is basically the same as that in Example 1, the difference is that: octadecyl polyoxyethylene ether methacrylate in step S1 is replaced by docosyl polyoxyethylene ether methacrylate, and the added amount is 0.4g.

[0038] Performance Testing

[0039] The three-in-one sodium polyacrylate thickener in Examples 1 to 6 and the commercially available sodium polyacrylate thickener were mixed with water to form a thickener solution with a mass fraction of 0.2%. The viscosity, viscosity retention rate and water retention rate of the thickener solution were then measured according to the following test method to evaluate its thickening effect, salt resistance and moisture retention performance. The specific test results are shown in Table 1.

[0040] 1) Viscosity test: measured using NDJ-1 rotational viscometer.

[0041] 2) Salt resistance test: First, the viscosity of the thickener solution was measured by NDJ-1 type rotational viscometer as A, then sodium chloride was added to the thickener solution (the addition amount was 0.15wt% of the thickener solution), mixed evenly and allowed to stand for 20 minutes, and the viscosity of the thickener solution was measured again as B; viscosity retention rate = B / A×100%, the larger the viscosity retention rate, the better the salt resistance of the thickener.

[0042] 3) Moisturizing performance test: 30g of double fly powder (white powder) and 10g of 0.2% thickener solution (the weight of water in the thickener solution is m0) are mixed evenly, sealed and placed in a dark place for 30 minutes to allow the double fly powder to fully absorb the thickener solution, then spread it evenly on the surface of the carrier and gently press it, and the total weight at this time is weighed as m1; then the total weight is measured after being placed at room temperature and ventilated conditions for 48 hours as m2; Water retention rate = [1-(m1-m2) / m0]×100%, the higher the water retention rate, the better the moisturizing performance of the thickener.

[0043] Table 1 Performance of three-in-one sodium polyacrylate thickener and commercially available sodium polyacrylate thickener in Examples 1 to 6

[0044]

[0045] According to the data in Table 1, the viscosity of the three-in-one sodium polyacrylate thickener in Examples 1 to 6 is greater than or equal to 1700 mPa·s, and the viscosity retention rate under high salt conditions is more than 72%, and the water retention rate is greater than 60%, indicating that the three-in-one sodium polyacrylate thickener of the present invention has high viscosity, high salt resistance and high moisture retention. Moreover, compared with the commercially available sodium polyacrylate thickener, the viscosity, salt resistance and moisture retention of the three-in-one sodium polyacrylate thickener of the present invention are greatly improved.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A three-in-one sodium polyacrylate thickener, characterized in that: The invention comprises a copolymer of sodium acrylate and long-chain alkyl alcohol polyoxyethylene ether methacrylate and a moisturizing agent; the moisturizing agent is trehalose and / or hydroxyethyl cellulose.

2. The three-in-one sodium polyacrylate thickener according to claim 1, characterized in that: The mass percentage of the long-chain alkyl alcohol polyoxyethylene ether methacrylate relative to sodium acrylate is 0.5% to 10.0%.

3. The three-in-one sodium polyacrylate thickener according to claim 2, characterized in that: The mass percentage of the long-chain alkyl alcohol polyoxyethylene ether methacrylate relative to sodium acrylate is 1.0% to 6.0%.

4. The three-in-one sodium polyacrylate thickener according to claim 1, characterized in that: The mass percentage of the trehalose relative to sodium acrylate is 0.1% to 5.0%.

5. The three-in-one sodium polyacrylate thickener according to claim 4, characterized in that: The mass percentage of the trehalose relative to sodium acrylate is 0.5% to 3.0%.

6. The three-in-one sodium polyacrylate thickener according to claim 1, characterized in that: The mass percentage of the hydroxyethyl cellulose relative to sodium acrylate is 0.1% to 4.0%.

7. The three-in-one sodium polyacrylate thickener according to claim 6, characterized in that: The mass percentage of the hydroxyethyl cellulose relative to sodium acrylate is 0.2% to 2.0%.

8. The three-in-one sodium polyacrylate thickener according to any one of claims 1 to 7, characterized in that: The long-chain alkyl alcohol polyoxyethylene ether methacrylate includes at least one of octadecyl polyoxyethylene ether methacrylate, eicosyl polyoxyethylene ether methacrylate, and docosyl polyoxyethylene ether methacrylate.

9. The method for preparing the three-in-one sodium polyacrylate thickener according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: uniformly mixing sodium acrylate, long-chain alkyl alcohol polyoxyethylene ether methacrylate, a moisturizer, a solvent and a free radical initiator, and causing a free radical polymerization reaction to obtain a three-in-one sodium polyacrylate thickener.

10. Use of the three-in-one sodium polyacrylate thickener according to any one of claims 1 to 8 in daily cosmetics, coatings, cement mortar or textiles.

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