Antibacterial and environment-friendly hydrogel-based silk soap and preparation method thereof

Abstract

The invention relates to the technical field of soaps, and discloses a bacteriostatic and environment-friendly hydrogel-based silk soap and a preparation method thereof.The preparation method comprises the following steps that 1, citrus essential oil and olive oil are mixed and then heated to 90-95 DEG C in a water bath, then a sodium hydroxide solution is added and fully mixed, and soap liquid is formed; (2) adding the agar powder into water, hydrating and homogenizing the agar, and cooling to obtain agar hydrogel; and (3) mixing and stirring the agar hydrogel and the liquid soap, and adding the fibroin to obtain the hydrogel-based silk soap. The hydrogel-based silk soap provided by the invention can improve the environmental pollution condition while exerting the dirt-removing power of the soap, and can exert the effects of bacteriostasis and skin care.

Description

Technical Field

[0001] The invention belongs to the technical field of soaps, and more specifically relates to an antibacterial and environmentally friendly hydrogel-based silk soap and a preparation method thereof. Background Art

[0002] Soap is a common cleaning and skin care product in daily life with a long history. With the continuous development of science and technology, the continuous improvement and perfection of process equipment, various types of soaps have been launched one after another, and the quality and grade of products have been continuously improved. However, as the functions of soap increase, the frequency of use increases, which will produce microplastic problems and aggravate environmental pollution.

[0003] The main ingredient of traditional soap is surfactant. When the concentration of surfactant in soap washing wastewater is high, after discharge it will not only kill microorganisms in the water and reduce the degradation efficiency of other toxic substances, but also reduce the dissolved oxygen content in the water and even accelerate eutrophication of the water body, which is extremely harmful to the ecological environment. Summary of the invention

[0004] The main purpose of the present invention is to provide an antibacterial and environmentally friendly hydrogel-based silk soap and a preparation method thereof in view of the above problems. By introducing agar hydrogel to form a three-dimensional network structure, the diffusion rate of soap surfactant molecules can be effectively inhibited. By adding citrus essential oil and silk fibroin, the prepared soap has antibacterial, anti-inflammatory and skin-care properties.

[0005] In order to achieve the above object, the present invention is implemented by the following technical scheme: a method for preparing an antibacterial and environmentally friendly hydrogel-based silk soap, comprising the following steps:

[0006] (1) Mix citrus essential oil and olive oil, heat in a water bath to 90-95° C., add sodium hydroxide solution and mix thoroughly to form a soap solution;

[0007] (2) adding agar powder to water to hydrate and homogenize the agar, and then cooling to obtain an agar hydrogel;

[0008] (3) After mixing and stirring the agar hydrogel and soap solution, silk protein is added to obtain hydrogel-based silk soap.

[0009] Hydrogel is a three-dimensional hydrophilic polymer network that can swell in water. It is not only biocompatible to a large extent, but also forms a three-dimensional network structure after being added to a soap matrix at a certain volume fraction and dissolved in water, which can effectively inhibit the diffusion rate of soap surfactant molecules without reducing the degreasing and decontamination ability of the soap itself. When the diffusion rate of the surfactant molecules decreases, that is, its activity decreases, the concentration of the surfactant molecules in the washing wastewater will also decrease, thereby reducing the pollution of soap wastewater to soil, water bodies and organisms themselves.

[0010] The biologically active compounds in citrus essential oils are mainly monoterpenes, including d-citric acid, myrcene, pinene, etc., of which the content of d-citric acid reaches 50%-90%, and has multiple biological activities such as antioxidant and anti-inflammatory. Citrus essential oils can be used to replace a certain proportion of plant oils and fats to participate in the saponification reaction in the soap preparation process, so that the soap produced has antibacterial and anti-inflammatory properties.

[0011] Silk fibroin is a natural high molecular weight fibrous protein extracted from silk. It contains a variety of amino acid components, can maintain the pH balance of the skin and has good biocompatibility. Soap preparation is in an alkaline environment, and silk fibroin is easily hydrolyzed into water-soluble mixed amino acids under alkaline conditions. It has obvious hydrophilicity and is suitable for adding to water-in-oil products such as soap. After hydrolysis, silk fibroin forms a loose and disordered small molecular structure, which is easily soluble in water phase or dispersed in water phase, and difficult to dissolve in oil phase. When added to soap solution, it can be evenly dispersed in the external water phase of the soap-based emulsion, which is more conducive to contact and absorption with the skin; adding a certain proportion of agar hydrogel to swell in the solution to form a three-dimensional network structure that can retain moisture for a long time, which helps to moisturize and replenish the skin. Its special pore structure and pore size distribution can limit the activity of surfactant molecules while reducing pollution. At the same time, it can play a steric effect, slow down the diffusion rate of silk fibroin that is not in direct contact with the skin, and make silk fibroin produce a sustained release effect, prolonging the skin care time.

[0012] Further preferably, the ratio of the added amounts of the citrus essential oil, olive oil and sodium hydroxide solution is 100-120 g:150 g:60 mL.

[0013] Further preferably, the concentration of the sodium hydroxide solution is 50-60wt%.

[0014] Further preferably, the preparation of the citrus essential oil is as follows: collecting the orange peel, removing the orange pith inside the orange peel, and washing with water; vacuum drying the orange peel, grinding the dried orange peel, and sieving it with a 200-mesh screen to form a fine powder; adding the orange peel powder to distilled water, and extracting the essential oil using a distillation device.

[0015] Further preferably, the ratio of the added amount of the agar powder and water is 30-40g:60mL.

[0016] Further preferably, the agar hydration temperature is 90-95°C.

[0017] Further preferably, the mass ratio of the agar hydrogel to the soap solution is 15-25:100; more preferably, the mass ratio of the agar hydrogel to the soap solution is 15-20:100.

[0018] Further preferably, the mass ratio of the silk protein to the soap solution is 2-3:100.

[0019] Further preferably, the average molecular weight of the silk protein is 6000-8000Da.

[0020] The second technical solution of the present invention: a hydrogel-based silk soap prepared by the above preparation method.

[0021] Compared with the prior art, the present invention has the following advantages: (1) it can improve the environmental pollution while exerting the decontamination ability of soap; and (2) it can exert the effect of antibacterial skin care. DETAILED DESCRIPTION

[0022] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0023] Example 1

[0024] (1) Collect the orange peel, remove the inner orange peel, and wash it with mineral water. Remove dust, dirt, microorganisms and pesticide residues on the surface. Place the orange peel on a stainless steel tray and put it into a vacuum drying oven at 75°C for 4 hours to facilitate grinding. Put the dried peel into a grinder for grinding and sieve it with a 200-mesh screen to obtain a fine powder. Add the orange peel powder to distilled water and extract the essential oil using a Clevenger-type distillation device.

[0025] (2) At the same time, take 50g of water and weigh 30g of sodium hydroxide, mix and stir evenly to make the sodium hydroxide completely dissolved in water to form a sodium hydroxide solution, and control the standing temperature at 90°C.

[0026] (3) Take 100 g of citrus essential oil and 150 g of olive oil, put them into a beaker and heat them in a water bath to 90°C, then add 60 mL of sodium hydroxide solution and mix thoroughly to form a soap solution.

[0027] (4) 50 g of agar powder was added to 80 mL of water and placed in a high temperature environment of 90° C. to hydrate and homogenize the agar to ensure that the agar powder was completely dissolved. After cooling, an agar hydrogel was obtained.

[0028] (5) 15 g of agar hydrogel and 100 g of soap solution were fully mixed and stirred, and 2 g of silk protein with an average molecular weight of 6000 Da was added to obtain a hydrogel-based citrus essential oil composite silk soap.

[0029] Example 2

[0030] (1) Collect the orange peel, remove the inner orange peel, and wash it with mineral water. Remove dust, dirt, microorganisms and pesticide residues on the surface. Place the orange peel on a stainless steel tray and put it into a vacuum drying oven to dry at 75°C for 4 hours to facilitate grinding. Put the dried peel into a grinder for grinding and sieve it with a 200-mesh screen to obtain a fine powder. Add the orange peel powder to distilled water and extract the essential oil using a Clevenger-type distillation device.

[0031] (2) At the same time, take 50g of water and weigh 30g of sodium hydroxide, mix and stir evenly to make the sodium hydroxide completely dissolved in water to form a sodium hydroxide solution, and control the standing temperature at 90°C.

[0032] (3) Take 100 g of citrus essential oil and 150 g of olive oil, put them into a beaker and heat them in a water bath to 90°C, then add 60 mL of sodium hydroxide solution and mix thoroughly to form a soap solution.

[0033] (4) 50 g of agar powder was added to 80 mL of water and placed in a high temperature environment of 90° C. to hydrate and homogenize the agar to ensure that the agar powder was completely dissolved. After cooling, an agar hydrogel was obtained.

[0034] (5) 20 g of agar hydrogel and 100 g of soap solution were fully mixed and stirred, and 2 g of silk protein with an average molecular weight of 6000 Da was added to obtain a hydrogel-based citrus essential oil composite silk soap.

[0035] Example 3

[0036] (1) Collect the orange peel, remove the inner orange peel, and wash it with mineral water. Remove dust, dirt, microorganisms and pesticide residues on the surface. Place the orange peel on a stainless steel tray and put it into a vacuum drying oven to dry at 75°C for 4 hours to facilitate grinding. Put the dried peel into a grinder for grinding and sieve it with a 200-mesh screen to obtain a fine powder. Add the orange peel powder to distilled water and extract the essential oil using a Clevenger-type distillation device.

[0037] (2) At the same time, take 50g of water and weigh 30g of sodium hydroxide, mix and stir evenly to make the sodium hydroxide completely dissolved in water to form a sodium hydroxide solution, and control the standing temperature at 90°C.

[0038] (3) Take 100 g of citrus essential oil and 150 g of olive oil, put them into a beaker and heat them in a water bath to 90°C, then add 60 mL of sodium hydroxide solution and mix thoroughly to form a soap solution.

[0039] (4) 50 g of agar powder was added to 80 mL of water and placed in a high temperature environment of 90° C. to hydrate and homogenize the agar to ensure that the agar powder was completely dissolved. After cooling, an agar hydrogel was obtained.

[0040] (5) 25 g of agar hydrogel and 100 g of soap solution were fully mixed and stirred, and 2 g of silk protein with an average molecular weight of 6000 Da was added to obtain a hydrogel-based citrus essential oil composite silk soap.

[0041] Comparative Example 1 (relative to Example 1, too much agar hydrogel was added)

[0042] (1) Collect the orange peel, remove the inner orange peel, and wash it with mineral water. Remove dust, dirt, microorganisms and pesticide residues on the surface. Place the orange peel on a stainless steel tray and put it into a vacuum drying oven to dry at 75°C for 4 hours to facilitate grinding. Put the dried peel into a grinder for grinding and sieve it with a 200-mesh screen to obtain a fine powder. Add the orange peel powder to distilled water and extract the essential oil using a Clevenger-type distillation device.

[0043] (2) At the same time, take 50g of water and weigh 30g of sodium hydroxide, mix and stir evenly to make the sodium hydroxide completely dissolved in water to form a sodium hydroxide solution, and control the standing temperature at 90°C.

[0044] (3) Take 100 g of citrus essential oil and 150 g of olive oil, put them into a beaker and heat them in a water bath to 90°C, then add 60 mL of sodium hydroxide solution and mix thoroughly to form a soap solution.

[0045] (4) 50 g of agar powder was added to 80 mL of water and placed in a high temperature environment of 90° C. to hydrate and homogenize the agar to ensure that the agar powder was completely dissolved. After cooling, an agar hydrogel was obtained.

[0046] (5) 40 g of agar hydrogel and 100 g of soap solution were fully mixed and stirred, and 2 g of silk protein with an average molecular weight of 6000 Da was added to obtain a hydrogel-based citrus essential oil composite silk soap.

[0047] Comparative Example 2 (relative to Example 1, the amount of agar hydrogel added is too small)

[0048] (1) Collect the orange peel, remove the inner orange peel, and wash it with mineral water. Remove dust, dirt, microorganisms and pesticide residues on the surface. Place the orange peel on a stainless steel tray and put it into a vacuum drying oven at 75°C for 4 hours to facilitate grinding. Put the dried peel into a grinder for grinding and sieve it with a 200-mesh screen to obtain a fine powder. Add the orange peel powder to distilled water and extract the essential oil using a Clevenger-type distillation device.

[0049] (2) At the same time, take 50g of water and weigh 30g of sodium hydroxide, mix and stir evenly to make the sodium hydroxide completely dissolved in water to form a sodium hydroxide solution, and control the standing temperature at 90°C.

[0050] (3) Take 100 g of citrus essential oil and 150 g of olive oil, put them into a beaker and heat them in a water bath to 90°C, then add 60 mL of sodium hydroxide solution and mix thoroughly to form a soap solution.

[0051] (4) 50 g of agar powder was added to 80 mL of water and placed in a high temperature environment of 90° C. to hydrate and homogenize the agar to ensure that the agar powder was completely dissolved. After cooling, an agar hydrogel was obtained.

[0052] (5) 5 g of agar hydrogel and 100 g of soap solution were fully mixed and stirred, and 2 g of silk protein with an average molecular weight of 6000 Da was added to obtain a hydrogel-based citrus essential oil composite silk soap.

[0053] Comparative Example 3 (relative to Example 1, too much silk fibroin was added)

[0054] (1) Collect the orange peel, remove the inner orange peel, and wash it with mineral water. Remove dust, dirt, microorganisms and pesticide residues on the surface. Place the orange peel on a stainless steel tray and put it into a vacuum drying oven at 75°C for 4 hours to facilitate grinding. Put the dried peel into a grinder for grinding and sieve it with a 200-mesh screen to obtain a fine powder. Add the orange peel powder to distilled water and extract the essential oil using a Clevenger-type distillation device.

[0055] (2) At the same time, take 50g of water and weigh 30g of sodium hydroxide, mix and stir evenly to make the sodium hydroxide completely dissolved in water to form a sodium hydroxide solution, and control the standing temperature at 90°C.

[0056] (3) Take 100 g of citrus essential oil and 150 g of olive oil, put them into a beaker and heat them in a water bath to 90°C, then add 60 mL of sodium hydroxide solution and mix thoroughly to form a soap solution.

[0057] (4) 50 g of agar powder was added to 80 mL of water and placed in a high temperature environment of 90° C. to hydrate and homogenize the agar to ensure that the agar powder was completely dissolved. After cooling, an agar hydrogel was obtained.

[0058] (5) 15 g of agar hydrogel and 100 g of soap solution were fully mixed and stirred, and 5 g of silk protein with an average molecular weight of 6000 Da was added to obtain a hydrogel-based citrus essential oil composite silk soap.

[0059] Comparative Example 4 (relative to Example 1, the amount of silk fibroin added is too small)

[0060] (1) Collect the orange peel, remove the inner orange peel, and wash it with mineral water. Remove dust, dirt, microorganisms and pesticide residues on the surface. Place the orange peel on a stainless steel tray and put it into a vacuum drying oven at 75°C for 4 hours to facilitate grinding. Put the dried peel into a grinder for grinding and sieve it with a 200-mesh screen to obtain a fine powder. Add the orange peel powder to distilled water and extract the essential oil using a Clevenger-type distillation device.

[0061] (2) At the same time, take 50g of water and weigh 30g of sodium hydroxide, mix and stir evenly to make the sodium hydroxide completely dissolved in water to form a sodium hydroxide solution, and control the standing temperature at 90°C.

[0062] (3) Take 100 g of citrus essential oil and 150 g of olive oil, put them into a beaker and heat them in a water bath to 90°C, then add 60 mL of sodium hydroxide solution and mix thoroughly to form a soap solution.

[0063] (4) 50 g of agar powder was added to 80 mL of water and placed in a high temperature environment of 90° C. to hydrate and homogenize the agar to ensure that the agar powder was completely dissolved. After cooling, an agar hydrogel was obtained.

[0064] (5) 15 g of agar hydrogel and 100 g of soap solution were fully mixed and stirred, and 1 g of silk protein with an average molecular weight of 6000 Da was added to obtain a hydrogel-based citrus essential oil composite silk soap.

[0065] Comparative Example 5 (relative to Example 1, the average molecular weight of silk fibroin is too low)

[0066] (1) Collect the orange peel, remove the inner orange peel, and wash it with mineral water. Remove dust, dirt, microorganisms and pesticide residues on the surface. Place the orange peel on a stainless steel tray and put it into a vacuum drying oven at 75°C for 4 hours to facilitate grinding. Put the dried peel into a grinder for grinding and sieve it with a 200-mesh screen to obtain a fine powder. Add the orange peel powder to distilled water and extract the essential oil using a Clevenger-type distillation device.

[0067] (2) At the same time, take 50g of water and weigh 30g of sodium hydroxide, mix and stir evenly to make the sodium hydroxide completely dissolved in water to form a sodium hydroxide solution, and control the standing temperature at 90°C.

[0068] (3) Take 100 g of citrus essential oil and 150 g of olive oil, put them into a beaker and heat them in a water bath to 90°C, then add 60 mL of sodium hydroxide solution and mix thoroughly to form a soap solution.

[0069] (4) 50 g of agar powder was added to 80 mL of water and placed in a high temperature environment of 90° C. to hydrate and homogenize the agar to ensure that the agar powder was completely dissolved. After cooling, an agar hydrogel was obtained.

[0070] (5) 15 g of agar hydrogel and 100 g of soap solution were fully mixed and stirred, and 2 g of silk protein with an average molecular weight of 4000 Da was added to obtain a hydrogel-based citrus essential oil composite silk soap.

[0071] The main component of soap is sodium fatty acid, which can be decomposed into fatty acid radical and sodium ion in water to increase the content of organic matter in water, thereby causing water quality to deteriorate. And chemical oxygen demand (COD) is an index to measure the organic content in water, so the pollution degree of soap to the environment can be assessed by measuring the content of COD in sewage. Take four parts of 500mL water respectively and add them to beaker, take traditional soap (Nice Group Carving Brand), each 1g of soap in embodiment 1,2,3 and add them to water, stir to dissolve, and measure numerical value using COD detector, as shown in table 1.

[0072] Table 1 Chemical oxygen demand (COD)

[0073]

[0074]

[0075] Four square sebum-stained cloths with a side length of 70 cm were taken and placed in the decontamination tank in turn. The above four soapy waters were added respectively, and the decontamination ratios were measured, as shown in Table 2. The decontamination ratio of the laundry detergent is ≥0.3, which is qualified. The results show that the hydrogel can indeed inhibit the activity of soap surfactants, thereby reducing pollution to the environment. However, when the amount of hydrogel added is too much, the measured decontamination ratio will decrease, indicating that the activity of the surfactant is too low, which will affect the decontamination ability of the soap.

[0076] Table 2 Decontamination ability test

[0077] Decontamination ratio Example 1 2.2 Example 2 2.4 Example 3 1.8 Comparative Example 1 1.0 Comparative Example 2 2.4 Comparative Example 3 2.2 Comparative Example 4 2.2 Comparative Example 5 2.2

[0078] The artificial skin was placed in a contaminated liquid containing a certain number of bacteria to be contaminated with a certain number of bacteria. A sample from the skin surface was collected and inoculated onto a culture medium containing nutrients. The culture medium was cultured at 37° C. to allow bacteria to grow. The artificial skin was cleaned using the facial cleansers in Example 1, Example 2, and Example 3, respectively. After cleaning, the bacteria were grown using the same steps. The changes in the number of colonies before and after washing were recorded to obtain the antibacterial rate, as shown in Table 3.

[0079] Table 3 Antibacterial test

[0080]

[0081]

[0082] 500 mL of water was added to a beaker, 1 g of each soap in Examples 1-3 and Comparative Examples 1-5 was added to the water, and the mass concentration of silk fibroin was measured at 30 s and 60 s, as shown in Table 4. The results show that too much agar hydrogel is not conducive to the sustained release of silk fibroin, and too low an average molecular weight of silk fibroin will lead to too fast a sustained release speed, which is also not conducive to the sustained release of silk fibroin.

[0083] Table 4 Sustained release effect of silk fibroin

[0084] 30s 60s Example 1 1.0％ 1.2％ Example 2 0.8％ 1.0％ Example 3 0.6％ 0.7％ Comparative Example 1 0.1％ 0.3％ Comparative Example 2 1.1％ 1.4％ Comparative Example 3 1.5％ 1.7％ Comparative Example 4 0.4％ 0.6％ Comparative Example 5 1.3％ 1.8％

[0085] The data in Tables 1-4 show that the hydrogel-based silk soap of the present invention can significantly reduce the chemical oxygen demand in wastewater, showing excellent environmental protection effects. At the same time, it can significantly increase the decontamination ratio, and as long as it is controlled within a certain range, the decontamination ability will not be damaged.

[0086] The above embodiments of the present invention are merely examples for illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes and modifications can be made based on the above description. It is impossible to list all the embodiments here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for preparing an antibacterial and environmentally friendly hydrogel-based silk soap, characterized in that: The steps include: (1) Mix citrus essential oil and olive oil, heat in a water bath to 90-95° C., add sodium hydroxide solution and mix thoroughly to form a soap solution; (2) adding agar powder to water to hydrate and homogenize the agar, and then cooling to obtain an agar hydrogel; (3) After mixing and stirring the agar hydrogel and soap solution, silk protein is added to obtain hydrogel-based silk soap.

2. The method for preparing the antibacterial and environmentally friendly hydrogel-based silk soap according to claim 1, characterized in that: The ratio of the added amounts of the citrus essential oil, olive oil and sodium hydroxide solution is 100-120 g:150 g:60 mL.

3. The method for preparing the antibacterial and environmentally friendly hydrogel-based silk soap according to claim 1 or 2, characterized in that: The concentration of the sodium hydroxide solution is 50-60wt%.

4. The method for preparing the antibacterial and environmentally friendly hydrogel-based silk soap according to claim 1 or 2, characterized in that: The preparation of the citrus essential oil comprises the following steps: collecting the surface peel of an orange, removing the inner tangerine pith of the orange peel, and washing the orange peel with water; vacuum drying the orange peel, grinding the dried orange peel, and sieving the orange peel with a 200-mesh screen to form fine powder; adding the orange peel powder into distilled water, and extracting the essential oil with a distillation device.

5. The method for preparing the antibacterial and environmentally friendly hydrogel-based silk soap according to claim 1, characterized in that: The ratio of the added amount of the agar powder to the water is 30-40 g:60 mL.

6. The method for preparing the antibacterial and environmentally friendly hydrogel-based silk soap according to claim 1 or 5, characterized in that: The agar hydration temperature is 90-95°C.

7. The method for preparing the antibacterial and environmentally friendly hydrogel-based silk soap according to claim 1, characterized in that: The mass ratio of the agar hydrogel to the soap solution is 15-25:

100.

8. The method for preparing the antibacterial and environmentally friendly hydrogel-based silk soap according to claim 1 or 7, characterized in that: The mass ratio of the silk protein to the soap solution is 2-3:

100.

9. The method for preparing the antibacterial and environmentally friendly hydrogel-based silk soap according to claim 1 or 7, characterized in that: The average molecular weight of the silk protein is 6000-8000Da.

10. A hydrogel-based silk soap prepared by the preparation method according to any one of claims 1 to 9.

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