A multifunctional cosmetic additive of lignin / salicylic acid nanospheres

Abstract

The present invention discloses a multifunctional cosmetic additive comprising lignin / salicylic acid nanospheres. The preparation method of the lignin / salicylic acid nanospheres comprises the steps of chemically modifying lignin with an epoxypropyl quaternary ammonium salt, purifying the modified lignin, and self-assembling the modified lignin and salicylic acid. The lignin / salicylic acid nanospheres obtained using the method of the present invention have the advantage of excellent water solubility and can be directly added to cosmetics to obtain a daily chemical product with multiple functions including high-efficiency antibacterial, antioxidant, and sunscreen. The present invention solves the problem of water insolubility and low antibacterial activity of lignin and salicylic acid when used as cosmetic additives, thereby obtaining a multifunctional cosmetic additive and providing a new approach for the high-value utilization of lignin.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine chemicals, in particular to the cosmetic raw material industry, and specifically to a lignin / salicylic acid nanosphere multifunctional cosmetic additive. Background Art

[0002] Lignin is a core component of plant cell walls, comprising 10-35% of their dry weight. It is inexpensive, biocompatible, and renewable, making it an ideal raw material for future industrial applications. Currently, the primary source of lignin available to industry comes from waste streams from the pulping industry. The global pulping industry produces over 70 million tons of lignin annually, of which less than 10% is separated and utilized for high-value applications. Developing new pathways for lignin utilization has significant economic and social benefits.

[0003] Natural lignin is a polyphenolic polymer formed by the random polymerization of phenylpropane structural units through free radicals. Although the pulping process severely disrupts the natural lignin's connectivity, the polyphenolic structure of lignin is preserved. Due to its polyphenolic structure, plants began synthesizing lignin when they evolved from marine to terrestrial habitats to cope with the intense sunlight radiation found on land. Lignin also possesses antimicrobial activity, which plants use to defend against pathogenic microorganisms. Therefore, using lignin to synthesize functional materials with antimicrobial and UV-resistant properties is an important way to efficiently utilize lignin. Extensive research has explored the addition of lignin to cosmetics to create daily chemical products with sun protection properties.

[0004] However, due to its phenylpropane structure, lignin is insoluble in water and cannot be directly added to cosmetics. On the other hand, if lignin is dissolved in an organic solvent system such as ethanol and then added to cosmetics, the use of organic solvents will reduce the value of the cosmetics. Furthermore, industrial lignin has weak antimicrobial activity, typically only effective against Gram-positive bacteria and having no inhibitory effect on Gram-negative bacteria. These shortcomings of lignin seriously hinder its high-value utilization as a cosmetic additive. Summary of the Invention

[0005] The present invention chemically modifies lignin and further utilizes salicylic acid to drive the self-assembly of the modified lignin to obtain lignin / salicylic acid nanospheres. The lignin / salicylic acid nanospheres are well soluble in water to form a stable solution. They can also be directly added to cosmetics to obtain daily chemical products with multiple functions including high antibacterial activity, antioxidant properties, and sun protection. The multifunctional lignin / salicylic acid nanosphere cosmetic additive proposed by the present invention solves the problems of lignin's water insolubility and low antibacterial activity when used as a cosmetic additive, while simultaneously obtaining a product with multiple functions including high antibacterial activity, antioxidant properties, and sun protection, thereby increasing the utilization value of lignin.

[0006] Therefore, the first object of the present invention is to provide a method for preparing a lignin / salicylic acid nanosphere multifunctional cosmetic additive, which comprises the following steps: dissolving lignin, an alkali, and an epoxypropyl quaternary ammonium salt in water, heating the mixture to react, and obtaining modified lignin; neutralizing and purifying the modified lignin, and then reacting the mixture with salicylic acid to obtain the lignin / salicylic acid nanosphere multifunctional cosmetic additive.

[0007] Preferably, the preparation method comprises the following steps:

[0008] (1) adding lignin, alkali, and epoxypropyl quaternary ammonium salt to water to obtain an aqueous solution with a solid content of 2 to 30 wt%;

[0009] (2) heating the aqueous solution of step (1) to 30-80° C., stirring and reacting for 0.5-12 hours to obtain modified lignin;

[0010] (3) neutralizing the modified lignin in step (2) to a pH of 6 to 8, filtering through an ultrafiltration membrane with a molecular weight cutoff of 1,000 to 10,000, and washing to obtain purified modified lignin;

[0011] (4) The purified modified lignin from step (3) is prepared into an aqueous solution with a concentration of 0.1 to 5 wt%, salicylic acid is added, and the mass ratio of salicylic acid to purified modified lignin is (0.01 to 0.15):1. The mixture is stirred until the salicylic acid is completely dissolved, and dried to obtain a lignin / salicylic acid nanosphere multifunctional cosmetic additive.

[0012] Preferably, the mass ratio of the lignin, alkali and epoxypropyl quaternary ammonium salt is 1:(0.2-3):(1-10).

[0013] Preferably, the lignin is selected from at least one of groundwood lignin, mild acid hydrolyzed lignin, enzyme hydrolyzed lignin, sulfate lignin, Soda lignin or organic solvent lignin.

[0014] Preferably, the base is selected from at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide or ammonia water.

[0015] The second object of the present invention is to provide a lignin / salicylic acid nanosphere multifunctional cosmetic additive, which is prepared by the above-mentioned preparation method.

[0016] The third object of the present invention is to provide the use of the above-mentioned lignin / salicylic acid nanosphere multifunctional cosmetic additive in the preparation of cosmetics with antibacterial, antioxidant and / or sunscreen effects.

[0017] The fourth object of the present invention is to provide a cosmetic having antibacterial, antioxidant and / or sunscreen effects, which contains the above-mentioned lignin / salicylic acid nanosphere multifunctional cosmetic additive.

[0018] Preferably, the cosmetics include water-based cosmetics, emulsion-based cosmetics, and cream-based cosmetics.

[0019] Preferably, the water-based cosmetics include lotions or facial mask liquids; the emulsion-based cosmetics include moisturizing lotions, skin care essences, eye essences, sleeping masks, hydrating gels or cleansing milks; and the cream-based cosmetics include skin care creams or eye creams.

[0020] The present invention has the beneficial effects:

[0021] 1. Compared with existing technologies, the lignin / salicylic acid nanospheres provided by this invention can kill 99.9% of both Gram-positive and Gram-negative bacteria. This solves the problem that lignin is only effective against Gram-positive bacteria but not Gram-negative bacteria, expands the antimicrobial spectrum of lignin, and improves its antimicrobial activity.

[0022] 2. Compared with the existing technology, the lignin / salicylic acid nanospheres provided by the present invention can significantly increase the sun protection index of commercially available sunscreen from 21 to 92, significantly improving the sun protection effect of cosmetics.

[0023] 3. Compared with the existing technology, the lignin / salicylic acid nanospheres provided by the present invention have multiple functions such as antibacterial, antioxidant and sunscreen. They can be directly added to cosmetics, directly giving cosmetics multiple functions such as antibacterial, antioxidant and sunscreen in one step without the need to use multiple functional additives. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the morphology of lignin / salicylic acid nanospheres.

[0025] Figure 2 The antioxidant and sun protection effects of lignin / salicylic acid nanospheres. DETAILED DESCRIPTION

[0026] The following examples are provided to further illustrate the present invention, but are not intended to limit the present invention.

[0027] Example 1

[0028] (1) 10 g of ground wood lignin, 2 g of sodium hydroxide, and 10 g of epoxypropyl quaternary ammonium salt were added to 1078 mL of water to obtain an aqueous solution with a solid content of 2 wt%.

[0029] (2) heating the aqueous solution of step (1) to 80° C. and stirring the mixture for 0.5 hours to obtain modified lignin.

[0030] (3) After neutralizing the modified lignin in step (2) to a pH of 6, the modified lignin was filtered using an ultrafiltration membrane with a molecular weight cutoff of 1000, and washed to obtain purified modified lignin.

[0031] (4) The purified modified lignin of step (3) was prepared into an aqueous solution with a concentration of 0.1 wt%, salicylic acid was added, and the mass ratio of salicylic acid to purified modified lignin was 0.15:1. The mixture was stirred until the salicylic acid was completely dissolved, and dried to obtain a lignin / salicylic acid nanosphere multifunctional cosmetic additive ( Figure 1 ).

[0032] It has been determined that the quaternized lignin salicylic acid microspheres of this embodiment are easily soluble in water, and the particle size is between 110 and 140 nm. According to the "ASTM E2149-Determination of Antimicrobial Activity under Dynamic Contact Conditions", when the addition concentration is 4 mg / mL, the bactericidal rate against Escherichia coli is 99.92%, and the bactericidal rate against Staphylococcus aureus is 99.90%, showing good broad-spectrum antibacterial activity. According to the "Cosmetic Safety Technical Specifications-8.2 Sunscreen Cosmetics Sun Protection Index (SPF Value) Determination Method", when the addition amount is 1wt%, the free radical scavenging rate is 15%, showing good antioxidant properties. According to the "GB / T 39100-Determination of Polypeptide Antioxidant Activity DPPH Method", when the addition amount is 1wt%, the sun protection index of commercially available cosmetics can be increased from 21 to 64, showing a good sun protection effect ( Figure 2 ).

[0033] Example 2

[0034] (1) 10 g of ethanol solvent lignin, 30 g of sodium hydroxide, and 100 g of epoxypropyl quaternary ammonium salt were added to 327 mL of water to obtain an aqueous solution with a solid content of 30 wt%.

[0035] (2) heating the aqueous solution of step (1) to 30° C. and stirring the reaction for 12 hours to obtain modified lignin.

[0036] (3) After neutralizing the modified lignin in step (2) to a pH of 8, the modified lignin was filtered using an ultrafiltration membrane with a molecular weight cutoff of 10,000 and washed to obtain purified modified lignin.

[0037] (4) The purified modified lignin from step (3) is prepared into a 5 wt% aqueous solution, salicylic acid is added, and the mass ratio of salicylic acid to purified modified lignin is 0.01:1. The mixture is stirred until the salicylic acid is completely dissolved, and dried to obtain a lignin / salicylic acid nanosphere multifunctional cosmetic additive.

[0038] It has been determined that the quaternized lignin salicylic acid microspheres of this embodiment are easily soluble in water, and the particle size is 84 to 145 nm. According to "ASTM E2149-Determination of Antimicrobial Activity under Dynamic Contact Conditions", when the addition concentration is 4 mg / mL, the bactericidal rate against Escherichia coli is 99.89%, and the bactericidal rate against Staphylococcus aureus is 99.85%, showing good broad-spectrum antibacterial activity. According to "Cosmetic Safety Technical Specifications-8.2 Determination of Sunscreen Cosmetics Sun Protection Index (SPF Value)", when the addition amount is 1wt%, the free radical scavenging rate is 17%, showing good antioxidant properties. According to "GB / T 39100-Determination of Polypeptide Antioxidant Activity DPPH Method", when the addition amount is 1wt%, the sun protection index of commercially available cosmetics can be increased from 21 to 67, showing a good sun protection effect ( Figure 2 ).

[0039] Example 3

[0040] (1) 5 g of mild acid hydrolyzed lignin, 5 g of enzyme hydrolyzed lignin, 10 g of potassium hydroxide, 14 g of lithium hydroxide, and 20 g of epoxypropyl quaternary ammonium salt were added to 216 mL of water to obtain an aqueous solution with a solid content of 20 wt%.

[0041] (2) heating the aqueous solution of step (1) to 70° C. and stirring the reaction for 7 hours to obtain modified lignin.

[0042] (3) After neutralizing the modified lignin in step (2) to a pH of 7, the modified lignin was filtered using an ultrafiltration membrane with a molecular weight cutoff of 3000 and washed to obtain purified modified lignin.

[0043] (4) The purified modified lignin from step (3) is prepared into an aqueous solution with a concentration of 0.4 wt %, salicylic acid is added, and the mass ratio of salicylic acid to purified modified lignin is 0.06:1. The mixture is stirred until the salicylic acid is completely dissolved, and dried to obtain a lignin / salicylic acid nanosphere multifunctional cosmetic additive.

[0044] It has been determined that the quaternized lignin salicylic acid microspheres of this embodiment are easily soluble in water, and the particle size is 96 to 130 nm. According to the "ASTM E2149-Determination of Antimicrobial Activity under Dynamic Contact Conditions", when the addition concentration is 4 mg / mL, the bactericidal rate against Escherichia coli is 99.95%, and the bactericidal rate against Staphylococcus aureus is 99.92%, showing good broad-spectrum antibacterial activity. According to the "Cosmetic Safety Technical Specifications-8.2 Sunscreen Cosmetics Sun Protection Index (SPF Value) Determination Method", when the addition amount is 1wt%, the free radical scavenging rate is 18%, showing good antioxidant properties. According to the "GB / T 39100-Determination of Polypeptide Antioxidant Activity DPPH Method", when the addition amount is 1wt%, the sun protection index of commercially available cosmetics can be increased from 21 to 92, showing a good sun protection effect ( Figure 2 ).

[0045] Example 4

[0046] (1) 10 g of kraft lignin, 10 g of sodium hydroxide, 5 g of potassium hydroxide, 5 g of lithium hydroxide, 10 g of aqueous ammonia, and 100 g of epoxypropyl quaternary ammonium salt were added to 327 mL of water to obtain an aqueous solution with a solid content of 30 wt%.

[0047] (2) heating the aqueous solution of step (1) to 70° C. and stirring the mixture for 3 hours to obtain modified lignin.

[0048] (3) After neutralizing the modified lignin in step (2) to a pH of 7, the modified lignin was filtered using an ultrafiltration membrane with a molecular weight cutoff of 3000 and washed to obtain purified modified lignin.

[0049] (4) The purified modified lignin from step (3) is prepared into a 5 wt% aqueous solution, salicylic acid is added, and the mass ratio of salicylic acid to purified modified lignin is 0.15:1. The mixture is stirred until the salicylic acid is completely dissolved, and dried to obtain a lignin / salicylic acid nanosphere multifunctional cosmetic additive.

[0050] It has been determined that the quaternized lignin salicylic acid microspheres of this embodiment are easily soluble in water, and the particle size is 153 to 161 nm. According to "ASTM E2149-Determination of Antimicrobial Activity under Dynamic Contact Conditions", when the addition concentration is 4 mg / mL, the bactericidal rate against Escherichia coli is 99.92%, and the bactericidal rate against Staphylococcus aureus is 99.92%, showing good broad-spectrum antibacterial activity. According to "Cosmetic Safety Technical Specifications-8.2 Sunscreen Cosmetics Sun Protection Index (SPF Value) Determination Method", when the addition amount is 1wt%, the free radical scavenging rate is 13%, showing good antioxidant properties. According to "GB / T 39100-Determination of Polypeptide Antioxidant Activity DPPH Method", when the addition amount is 1wt%, the sun protection index of commercially available cosmetics can be increased from 21 to 45, showing a good sun protection effect ( Figure 2 ).

[0051] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a multifunctional cosmetic additive of lignin / salicylic acid nanospheres, characterized in that: The following steps are involved: (1) adding lignin, alkali, and epoxypropyl quaternary ammonium salt to water to obtain an aqueous solution with a solid content of 2 to 30 wt %; the mass ratio of the lignin, alkali, and epoxypropyl quaternary ammonium salt is 1:(0.2 to 3):(1 to 10); (2) heating the aqueous solution of step (1) to 30-80° C. and stirring the solution for 0.5-12 hours to obtain modified lignin; (3) neutralizing the modified lignin in step (2) to a pH of 6 to 8, filtering through an ultrafiltration membrane with a molecular weight cutoff of 1,000 to 10,000, and washing to obtain purified modified lignin; (4) The purified modified lignin obtained in step (3) is prepared into an aqueous solution with a concentration of 0.1-5 wt%, salicylic acid is added, and the mass ratio of salicylic acid to purified modified lignin is (0.01-0.15):

1. The mixture is stirred until the salicylic acid is completely dissolved, and dried to obtain a lignin / salicylic acid nanosphere multifunctional cosmetic additive.

2. The preparation method according to claim 1, characterized in that The lignin is selected from at least one of groundwood lignin, mild acid hydrolyzed lignin, enzyme hydrolyzed lignin or sulfate lignin.

3. The preparation method according to claim 1, characterized in that The alkali is selected from at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide or ammonia water.

4. The multifunctional cosmetic additive of lignin / salicylic acid nanospheres prepared by the preparation method according to any one of claims 1 to 3.

5. Use of the lignin / salicylic acid nanosphere multifunctional cosmetic additive according to claim 4 in the preparation of cosmetics having antibacterial, antioxidant and / or sunscreen effects.

6. A cosmetic having antibacterial, antioxidant and / or sunscreen effects, characterized in that: A multifunctional cosmetic additive containing the lignin / salicylic acid nanospheres according to claim 4.

7. The cosmetic according to claim 6, characterized in that The cosmetics include water-based cosmetics, emulsion-based cosmetics, and cream-based cosmetics.

Images