A mild surfactant composition and its preparation method and use

Abstract

The present application relates to the field of daily chemicals, disclose a kind of mild surfactant composition, by the following components: sodium cocamphodipropionate, PEG-80 sorbitan laurate, round stone flower root extract, camellia seed extract and deionized water, its preparation method, including the following steps: (1) deionized water is added to the pot, add sodium cocamphodipropionate, PEG-80 sorbitan laurate, stirring homogenization;(2) after being fully dispersed evenly, stirring is heated, heat preservation stirring;(3) after heat preservation, cooling, stirring cooling, round stone flower root extract, camellia seed extract is added in sequence, stirring can be obtained finished product.The product of the present application can effectively reduce the irritation of anionic surfactant to eyes and skin while maintaining excellent foam performance, solving the problem that irritation and foam performance are difficult to be considered in the prior art.

Description

Technical Field

[0001] This invention relates to the field of daily chemical products, and more particularly to a mild surfactant composition, its preparation method, and its application. Background Technology

[0002] Anionic surfactants are the most widely used cleaning ingredients in shampoos, shower gels, facial cleansers, and other personal care products due to their excellent detergency, foaming properties, and cost-effectiveness. Sodium C14-16 olefin sulfonate, sodium lauryl ether sulfate (SLES), and sodium lauryl sulfate (SDS / K12) are representative examples of anionic surfactants. However, anionic surfactants can irritate the skin and mucous membranes. The irritation mechanism lies in the fact that anionic surfactant molecules carry a negative charge, readily binding to positively charged groups in the stratum corneum of the skin. This allows the surfactant molecules to penetrate the stratum corneum, interacting with proteins in the skin, leading to protein denaturation and disruption of intercellular lipid structures. This results in skin barrier damage, dehydration of the stratum corneum, and dryness and tightness. Infants and people with sensitive skin are particularly sensitive to this.

[0003] Existing methods for reducing the irritation of anionic surfactants mainly include: (1) compounding with amphoteric surfactants; (2) compounding with nonionic surfactants; and (3) adding soothing and anti-allergic active ingredients. Among these, amphoteric surfactants (such as disodium cocoamphodiacetate) and nonionic surfactants (such as PEG-80 sorbitan laurate) can reduce the irritation of the system by forming mixed micelles, reducing the critical micelle concentration (CMC), and reducing the content of free surfactants. Studies have shown that PEG-80 sorbitan laurate can significantly increase the particle size of surfactant micelles, reduce the penetration of the cleansing system into the stratum corneum of the skin, and thus reduce the irritation to the skin.

[0004] However, when the proportion of anionic surfactants is high, the anti-irritant effect of relying solely on surfactant blends is limited, and excessive addition of amphoteric / nonionic surfactants can significantly dilute the system, leading to a decrease in foam height. How to effectively reduce irritation while maintaining excellent foam performance is a technical challenge facing the industry. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the technical problem solved by the present invention is to overcome the shortcomings of the prior art, such as the strong irritation of anionic surfactants and the fact that existing anti-irritation methods weaken foam performance, and to provide a mild surfactant composition that can effectively reduce the irritation of anionic surfactants while maintaining or even improving foam performance.

[0006] To solve the above-mentioned technical problems, the present invention provides a mild surfactant composition, which, by mass percentage, consists of the following components: Disodium cocoamphodiacetate 1%–110%; PEG-80 dehydrated sorbitan lauryl ester 0.3%–14%; Root extract of *Lithocarpus paniculata*: 0.5%–15%; Camellia seed extract 0.5%–15%; Deionized water balance; The sum of the mass percentages of the above components is 100%; The method for preparing the composition includes the following steps: (1) Add deionized water to the pot, add disodium cocoamphodiacetate and PEG-80 dehydrated sorbitan laurate, and stir at 2000 rpm to 3000 rpm for 3 minutes to homogenize. (2) After being fully dispersed and evenly distributed, stir at a speed of 200 rpm to 600 rpm and heat to 80℃ to 85℃, then keep warm and stir for 20 minutes; (3) After heat preservation, cool down and stir at 200 rpm to 600 rpm to cool down to 35℃ to 45℃. Add the root extract of *Sedum conicaria* and the seed extract of *Camellia sinensis* in sequence, and stir at 400-1000 rpm for 3 to 5 minutes to obtain the finished product.

[0007] Preferably, a mild surfactant composition comprises, by weight percentage, the following components: Disodium cocoamphodiacetate 2%–8%; PEG-80 dehydrated sorbitan lauryl ester 0.5%–3%; Conical stone flower root extract 1%–3%; Camellia seed extract 1%–3%; Deionized water balance; The sum of the mass percentages of the above components is 100%; Preferably, the weight ratio of the disodium cocoamphodiacetate to the PEG-80 sorbitan lauryl ester is (1-5):1.

[0008] Preferably, the weight ratio of the *Lithocarpus conica* root extract to the *Camellia sinensis* seed extract is 1:(0.5-2).

[0009] This mild surfactant composition can be added as a de-irritant additive to personal care products containing anionic surfactants.

[0010] The present invention also provides a mild washing and care product containing the above-described mild surfactant composition, comprising anionic surfactant and the above-described mild surfactant composition.

[0011] Preferably, the anionic surfactant is at least one of sodium C14-16 olefin sulfonate, sodium lauryl ether sulfate, and sodium lauryl sulfate.

[0012] Preferably, the mild surfactant composition is added to the washing and care product at an amount of 5% to 30%, and the anionic surfactant is added to the washing and care product at an amount of 3% to 20%.

[0013] The advantages of this invention compared to existing technologies are: (1) Multiple synergistic destimulation mechanisms with significant effects.

[0014] The irritation of anionic surfactants is reduced synergistically through a dual approach of "chemical de-irritation + biological de-irritation". Disodium cocoamphodiacetate forms mixed micelles with anionic surfactants, reducing the concentration of free surfactants; PEG-80 dehydrated sorbitan laurate further increases the micelle size, reducing surfactant penetration into the stratum corneum; the natural saponins in the root extract of *Lithocarpus conocissus* and the seed extract of *Camellia sinensis* have biosurfactant activity, which can encapsulate free anionic surfactants and exert a soothing and repairing effect. These four components work synergistically through different mechanisms to significantly reduce the eye and skin irritation of the system; eye irritation tests show that the eye irritation score of the anionic surfactant system can be reduced from moderate irritation (3-4 points) to no irritation to very slight irritation (0-1 point); multi-skin tests show a significant reduction in the cumulative irritation score over 14 days.

[0015] (2) The foam performance is significantly improved.

[0016] Camellia seed extract is rich in tea saponins, exhibiting excellent foaming properties and foam stability; triterpenoid saponins in *Lithocarpus conica* root extract also possess good foaming ability. The addition of these two natural saponins effectively compensates for the decrease in foam height caused by the replacement of some anionic surfactants with amphoteric / nonionic surfactants, achieving "reduced irritation without reduced foam." Attached Figure Description

[0017] Figure 1 This is a flowchart of the preparation method of the present invention; Figure 2 shows the actual foam height of controls 1-2 and examples 1-3 at the initial stage and after 5 minutes. Figure 3 Bar charts showing the initial and 5-minute foam heights of controls 1-2 and examples 1-3; Figure 4Bar charts showing the eye irritation test scores of the anionic surfactant systems before and after the addition of controls 1-2 and examples 1-3; Figure 5 Bar chart showing the scores of multiple skin irritation tests for the anionic surfactant systems before and after the addition of controls 1-2 and examples 1-3. Detailed Implementation

[0018] The specific implementation effects of the present invention will be further explained below with reference to embodiments and experiments, but this is not intended to limit the present invention.

[0019] Unless otherwise specified, the raw materials, reagents or devices used in the various embodiments of the present invention can be obtained from conventional commercial sources or by existing known methods.

[0020] A mild surfactant composition, as detailed in Examples 1 to 3, comprises the following components by weight percentage, as shown in Table 1 below: Table 1

[0021] like Figure 1 The preparation methods of Examples 1 to 3 shown above include the following steps: (1) Add deionized water to the pot, add disodium cocoamphodiacetate and PEG-80 dehydrated sorbitan laurate, and stir at 2000 rpm to 3000 rpm for 3 minutes to homogenize. (2) After being fully dispersed and evenly distributed, stir at a speed of 200 rpm to 600 rpm and heat to 80℃ to 85℃, then keep warm and stir for 20 minutes; (3) After heat preservation, cool down and stir at 200 rpm to 600 rpm to cool down to 35℃ to 45℃. Add the root extract of *Sedum conicaria* and the seed extract of *Camellia sinensis* in sequence, and stir at 400-1000 rpm for 3 to 5 minutes to obtain the finished product.

[0022] The root extract of Gypsophila paniculata is rich in triterpenoid saponins, which have natural surface-active properties and soothing and repairing effects.

[0023] Camellia seed extract is rich in tea saponins, a natural nonionic surfactant with extremely low skin irritation. It also exhibits excellent foaming properties and foam stability, with a low critical micelle concentration, which reduces the content of free surfactants. Existing research indicates that camellia seed extract can significantly enhance the foaming power of a system, compensating for the insufficient foaming properties of mild surfactant systems. Combining camellia seed extract with mild surfactants holds promise for reducing irritation while compensating for any loss in foaming performance.

[0024] Comparative Example To verify the anti-irritant and foaming performance advantages of this invention, the following control systems were set up (all using 10% C14-16 olefin sulfonate sodium as the anionic surfactant base system): Control group 1: 10% C14-16 olefin sulfonate sodium + 15% deionized water (anionic surfactant used alone) Control group 2: 10% C14-16 olefin sulfonate sodium + 15% disodium cocoamphodiacetate (containing only amphoteric surfactant) Performance testing I. Foam Height Test (Ross-Miles Method) Following the ASTM D1173 standard method, the foaming properties of 0.25% surfactant aqueous solutions in each system were determined using a Ross-Miles foam apparatus at 40°C.

[0025] Figure 2 shows the actual foam height of control group 1, control group 2, and examples 1-3, where: Figure 2-a1 This is a diagram showing the initial foam height of control group 1. Figure 2-a2 This is a diagram showing the actual foam height of the control group after 15 minutes. Figure 2- b 1 shows the initial foam height of control group 2. Figure 2-b2 This is a diagram showing the actual foam height of control group 2 after 5 minutes. Figure 2- c 1 is the initial foam height diagram of Example 1. Figure 2-c2 This is a diagram showing the actual foam height after 5 minutes in Example 1; Figure 2- d 1 is the initial foam height diagram of Example 2. Figure 2-d2 This is a diagram showing the actual foam height after 5 minutes in Example 2; Figure 2- e Figure 1 shows the initial foam height in Example 3. Figure 2-e2 This is a diagram showing the actual foam height after 5 minutes in Example 3; The specific measurement results are shown in Table 1 below. Figure 3 As shown: Table 1:

[0026] From the data in point 1, we can see that: The initial foam height of control group 1 (sodium C14-16 olefin sulfonate alone) was 130 mm, but it dropped to 112 mm after 5 minutes, with a foam stability of only 86.15%.

[0027] The initial foam height of control group 2 (containing only disodium cocoamphodiacetate) decreased to 11.1 mm, which was about 15% lower than that of control group 1. Although the foam stability was improved to 93.69%, it was still lower than that of the example group.

[0028] Examples 1-3 (containing PEG-80 dehydrated sorbitan laurate + *Lithocarpus conocissus* root extract + *Camellia sinensis* seed extract) had an initial foam height of 114–125 mm, higher than control group 2 and close to the level of control group 1; the foam retention rate after 5 minutes was as high as 94.26%–96.8%, far superior to control groups 1 and 2. This confirms that the natural saponins in *Camellia sinensis* seed extract and *Lithocarpus conocissus* root extract can effectively compensate for the foam height loss due to the addition of amphoteric surfactants and significantly enhance foam stability, achieving the technical effect of "reducing irritation without reducing foam".

[0029] II. Mildness Test – Eye Irritation Test The acute eye irritation test method in the "Cosmetic Safety Technical Specifications" was used to conduct the test on rabbits.

[0030] Take 3 New Zealand rabbits, gently pull open the lower eyelid of the right eye of the rabbit, and drip 100mg of the test substance into the conjunctival sac. Passively close the upper and lower eyelids for 1 second. At 30 seconds, rinse with a sufficient amount of water with a fast flow rate that will not cause damage to the animal's eye for 30 seconds. The left eye is left untreated as a self-control.

[0031] The animals' eyes were examined using a magnifying glass and a pupillary light at 1h, 24h, 48h, 72h, 4d, and 7d after the test substance was instilled. Simultaneously, after the 24-hour observation and recording, all animals' eyes were examined with sodium fluorescein at each examination. Eye irritation reactions were recorded and integrated according to Table | of Chapter 6, Part 5 of the "Cosmetic Safety Technical Specifications" (2015 Edition). If no irritation reaction was observed after 72h, the experiment was terminated. If corneal involvement or other eye irritation was observed that did not resolve within 7d, the observation period was extended to 21d, and observation reports for 7d, 14d, and 21d were provided. Specific data are shown in Table 2 below. Figure 4 : Table 2

[0032] The data in Table 2 shows that: The control group 1 (using sodium C14-16 olefin sulfonate alone) had an eye irritation score of 4.0, which is considered moderate irritation, indicating that anionic surfactants alone have significant eye irritation.

[0033] The control group 2 (containing only disodium cocoamphodiacetate) had an eye irritation score of 2.5, which, although lower, was still considered mild irritation, and the effect of reducing irritation was limited.

[0034] Examples 1-3 (containing PEG-80 sorbitan laurate + Lithops conicaria root extract + Camellia seed extract) showed eye irritation scores reduced to 0-0.5 points, indicating no to very mild irritation. This demonstrates that PEG-80 sorbitan laurate increases micelle size and reduces surfactant penetration into mucosal tissues. Lithops conicaria root extract and Camellia seed extract, through the encapsulation of free anionic surfactants by natural saponins, exert a soothing and repairing effect. The three ingredients, together with amphoteric surfactants, form a synergistic effect with multiple anti-irritation mechanisms, resulting in a significantly better anti-irritation effect than a single compound approach.

[0035] III. Mildness Test – Multi-skin Test Following the repeated skin irritation test method in the "Cosmetic Safety Technical Specifications," each system was applied to the shaved skin area on the back of rabbits once daily for 14 consecutive days. Skin irritation reactions such as erythema and edema were observed and recorded, and the average daily irritation score was calculated. Specific data are shown in Table 3 below. Figure 5 : Table 3

[0036] The data in Table 3 shows that: The average daily irritation score of control group 1 (sodium C14-16 olefin sulfonate alone) was 2.5 points (moderate irritation) in the multi-skin test, indicating that long-term contact with anionic surfactants on the skin can cause cumulative irritation and damage.

[0037] The average daily stimulation score of control group 2 (containing only disodium cocoamphodiacetate) was 1.8 (mild stimulation), indicating a limited effect in reducing stimulation, and the cumulative stimulation after 14 days was still quite significant.

[0038] In Examples 1-3, the average daily irritation score in the multi-skin test was 0-0.2 points (no irritation to very slight irritation), significantly better than that of Control Group 1 and Control Group 2. This indicates that the composition of the present invention can effectively reduce the cumulative irritation of anionic surfactants to the skin, has good skin gentleness, and is suitable for use in infants and children with sensitive skin.

[0039] This invention can be widely used in various personal care products containing anionic surfactants, such as shampoos, shower gels, facial cleansers, and baby care products. Through a multi-synergistic anti-irritation mechanism of amphoteric / nonionic surfactants and natural plant extracts, it effectively reduces the eye and skin irritation of anionic surfactants while maintaining excellent foam performance. This solves the technical problem of difficulty in balancing anti-irritation and foam performance in existing technologies. It is particularly suitable for baby care products and cleansing products for sensitive skin that require high gentleness, and has broad market application prospects.

[0040] The embodiments of the present invention have been described in detail above with reference to the examples, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations to these embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A mild surfactant composition, characterized in that, It consists of the following components by mass percentage: Disodium cocoamphodiacetate 1%–10%; PEG-80 dehydrated sorbitan lauryl ester 0.3%–14%; Root extract of *Lithocarpus paniculata*: 0.5%–15%; Camellia seed extract 0.5%–15%; Deionized water balance; The sum of the mass percentages of the above components is 100%; The method for preparing the composition includes the following steps: (1) Add deionized water to the pot, add disodium cocoamphodiacetate and PEG-80 dehydrated sorbitan laurate, and stir at 2000 rpm to 3000 rpm for 3 minutes to homogenize. (2) After being fully dispersed and evenly distributed, stir at a speed of 200 rpm to 600 rpm and heat to 80℃ to 85℃, then keep warm and stir for 20 minutes; (3) After heat preservation, cool down and stir at 200 rpm to 600 rpm to cool down to 35℃ to 45℃. Add the root extract of *Sedum conicaria* and the seed extract of *Camellia sinensis* in sequence, and stir at 400-1000 rpm for 3 to 5 minutes to obtain the finished product.

2. The mild surfactant composition according to claim 1, characterized in that, It consists of the following components by mass percentage: Disodium cocoamphodiacetate 2%–8%; PEG-80 dehydrated sorbitan lauryl ester 0.5%–3%; Conical stone flower root extract 1%–3%; Camellia seed extract 1%–3%; Deionized water balance; The sum of the mass percentages of the above components is 100%.

3. The mild surfactant composition according to claim 1 or 2, characterized in that, The weight ratio of the disodium cocoamphodiacetate to the PEG-80 dehydrated sorbitan laurate is (1-5):

1.

4. The mild surfactant composition according to claim 1 or 2, characterized in that, The weight ratio of the *Sedum conicaria* root extract to the *Camellia sinensis* seed extract is 1:(0.5-2).

5. The mild surfactant composition according to claim 1 or 2, characterized in that, It can be added as a de-irritant additive to personal care products containing anionic surfactants.

6. The mild cleansing and conditioning product containing a mild surfactant composition according to claim 5, characterized in that, The mild washing and care product contains anionic surfactants and the above-mentioned mild surfactant composition.

7. The mild washing and care product containing a mild surfactant composition according to claim 6, characterized in that, The anionic surfactant is at least one of sodium C14-16 olefin sulfonate, sodium lauryl ether sulfate, and sodium lauryl sulfate.

8. The mild cleansing and conditioning product containing a mild surfactant composition according to claim 6, characterized in that, The mild surfactant composition is added to the washing and care product at an amount of 5% to 30%, and the anionic surfactant is added to the washing and care product at an amount of 3% to 20%.

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