A low-water-activity, preservative-free wash and care particle and a method for its preparation

Abstract

The application belongs to the technical field of daily chemical products, and particularly relates to a low-water-activity preservative-free washing and protecting granule and a preparation method thereof. The preparation method comprises the following steps: S1, uniformly mixing other ingredients except a thickening agent, drying, and crushing into powder; S2, mixing the thickening agent with water to prepare a thickening agent aqueous solution, then adding the powder prepared in step S1 into a granulator, spraying the thickening agent aqueous solution into the granulator, controlling the air temperature in the granulator through an air blower, and manufacturing granules, i.e. obtaining the washing and protecting granule; the mass concentration of the thickening agent aqueous solution is 0.3-0.7%; and the air temperature in the granulator is controlled to be 80-90 DEG C. The application can ensure the formation of ideal granule structure and uniform particle size distribution, and significantly reduce the water activity of the granule, so as to ensure the quality, stability and overall washing and protecting performance of the preservative-free granule.

Description

Technical Field

[0001] This invention belongs to the field of daily chemical products technology, and in particular relates to a low water activity preservative-free washing and care granules and its preparation method. Background Technology

[0002] Currently, traditional liquid personal care products, including shampoos and shower gels, contain certain chemical ingredients, especially preservatives, that may irritate the skin, causing allergic reactions and affecting user comfort and health. Furthermore, the production and packaging processes of liquid personal care products typically require large amounts of water, which not only increases production costs but also burdens the environment. Especially given today's increasing global water scarcity, reducing water consumption during production has become a pressing issue for the personal care product industry.

[0003] Therefore, developing a specific process to prepare preservative-free solid shampoo and conditioner granules has become an important market demand. Solid shampoo and conditioner granules not only reduce the use of chemical ingredients, avoiding allergies and irritation, but also reduce water consumption during production and transportation through simplified formulations and convenient packaging. Furthermore, these granular products dissolve simply in water, reducing the reliance on water resources compared to traditional liquid shampoo and conditioner products, and facilitating precise dosage control to avoid waste. Simultaneously, the unique granular form helps extend the product's shelf life, reducing the need for preservatives and further enhancing product safety and environmental friendliness. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a low water activity, non-corrosive cleaning and care granules and its preparation method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention includes:

[0006] In a first aspect, the present invention provides a method for preparing low water activity, preservative-free cleaning and conditioning granules, the preparation method comprising the following steps:

[0007] S1. Take the following raw materials by weight: 22-61 parts surfactant, 10-15 parts filler, 1-5 parts anti-caking agent, 2.1-21 parts humectant, 0.1-1 part pH adjuster and 0.5-1.5 parts fragrance. Mix the weighed raw materials evenly, dry them, and pulverize them into powder.

[0008] S2. Weigh the thickener and mix it with water to prepare a thickener aqueous solution;

[0009] S3. Add the powder described in step S1 to the granulator, and then spray the thickener aqueous solution described in step S2 into the granulator. Control the air temperature in the granulator to 80-90℃ to produce granules, thus obtaining the washing and care granules.

[0010] The mass concentration of the thickener in the aqueous thickener solution is 0.3-0.7%.

[0011] This invention uses the above-mentioned specific process to prepare solid washing and care particles from selected components. By spraying a thickener aqueous solution onto the surface of the mixed component powder to form solid particles, the adhesion and uniformity between components can be effectively improved, and a thin film can be formed on the particle surface to a certain extent to encapsulate the particles, thereby preventing water from penetrating too quickly and reducing water diffusion, thus effectively reducing the water activity of the washing and care particles.

[0012] Furthermore, experimental investigations revealed that the concentration of the thickener aqueous solution and the air temperature during granulation significantly affect the final granule formation and water activity. When the thickener aqueous solution concentration is too low, the inter-component bonding is weak, resulting in loose granules during granulation, leading to uneven particle size or brittleness. Conversely, when the thickener aqueous solution concentration is too high, the viscosity is high, reducing particle flowability and affecting particle uniformity and dispersibility. When the air temperature during granulation is too low, the granules are difficult to dry completely, resulting in poor hardness, high moisture absorption, and high water activity. When the temperature is too high, the particle surface hardens while the interior contains excessive water, affecting particle uniformity and formation. Additionally, high temperatures may affect the performance of the thickener, leading to degradation or changes in its properties, thus impacting the particle structure and stability.

[0013] Therefore, the present invention uses the above-mentioned specific process to prepare washing and care granules. By using the optimized thickener concentration and granulation temperature, the disintegration or non-formation of the granules can be effectively avoided, and the uniformity of the granule size can be ensured. At the same time, the water activity of the granules is significantly reduced, thereby ensuring the quality and stability of the preservative-free granules.

[0014] Preferably, in step S2, the mass ratio of the thickener aqueous solution to the powder is (0.2-0.4):1.

[0015] Preferably, the mass ratio of the thickener aqueous solution to the powder is 0.3:1.

[0016] In the preparation of shampoo and conditioner granules, the mass ratio of the thickener aqueous solution to the powder is also an important factor in controlling the quality and performance of the granules. When the two are prepared in the above-mentioned optimal mass ratio, it can ensure that the components form an ideal granular structure and uniform particle size distribution, effectively improve the mechanical strength of the granules, reduce the risk of granules being easily damaged or broken during storage or transportation, and also ensure the solubility of the granules and hydration during use to a certain extent, thereby ensuring a good sensory experience for users.

[0017] Preferably, in step S2, a blower is used to control the air temperature in the granulator, and the speed of the blower is controlled at 15-50Hz; and / or, the outlet air temperature of the granulator is controlled below 50℃ and the humidity is controlled at 20-40%.

[0018] Experimental research revealed that the blower speed and humidity control during granulation significantly impact the morphology, structure, and product stability of the granules. If these parameters exceed the preferred range, the uniformity and integrity of the granules will be affected, leading to granule adhesion or the formation of excessively small clumps. In particular, excessively low humidity can cause granules to easily break or fail to form the desired shape, while excessively high humidity may cause granules to easily clump, thus affecting their morphology and flowability. Therefore, precise control of the parameters during the preparation of these granules is crucial to effectively ensure the quality, stability, and final performance of the granules.

[0019] More preferably, the air temperature in the granulator is controlled at 85°C; the outlet air temperature of the granulator is controlled at 30°C, and the humidity is controlled at 30%.

[0020] Preferably, the mass concentration of the thickener in the thickener aqueous solution is 0.5%.

[0021] Preferably, after the granules are manufactured, they are screened to obtain 10-100 mesh granules, thus obtaining the shampoo and conditioner granules.

[0022] Preferably, the raw materials for preparing the preservative-free washing and care granules include the following components in parts by weight: 45 parts surfactant, 12 parts filler, 3 parts anti-caking agent, 15 parts humectant, 0.5 parts pH adjuster, and 1 part fragrance.

[0023] Experimental research has shown that, under the same preparation process conditions, when the components are prepared in the above-mentioned optimal dosage ratio for washing and care granules, the components work together to minimize the water activity of the washing and care granules and improve their performance. The long-term stability of the granules can be effectively guaranteed without the addition of preservatives.

[0024] Preferably, the thickener comprises hydroxypropyl methylcellulose, xanthan gum, and chitosan, wherein the mass ratio of hydroxypropyl methylcellulose, xanthan gum, and chitosan is (0.1-1):(0.1-0.5):(0.1-0.3).

[0025] Preferably, the mass ratio of hydroxypropyl methylcellulose, xanthan gum, and chitosan is 0.5:0.3:0.2.

[0026] In preparing the shampoo and conditioner granules, the inventors also explored the selection of thickeners. Through experiments, they found that when hydroxypropyl methylcellulose, xanthan gum, and chitosan were combined within the above-mentioned preferred range as thickeners for the preparation of shampoo and conditioner granules, the interaction between the three effectively avoided the problem of slow or uneven dissolution caused by a single thickener. Furthermore, by adjusting the viscosity, the structure and performance of the granules were better improved, thus significantly enhancing the stability of the granules. In addition, the antibacterial properties of chitosan could complement the properties of the other two thickeners, thereby helping to increase the antibacterial protection of the shampoo and conditioner granules without preservatives, further enhancing the long-term stability of the granules.

[0027] Preferably, the surfactant comprises hexadecyltrimethylammonium chloride, cocamidopropyl betaine, sodium lauryl sulfate, and sodium cocoyl ethanesulfonate; the mass ratio of hexadecyltrimethylammonium chloride, cocamidopropyl betaine, sodium lauryl sulfate, and sodium cocoyl ethanesulfonate is (5-20):(5-15):(10-20):(2-6).

[0028] Preferably, the mass ratio of hexadecyltrimethylammonium chloride, cocamidopropyl betaine, sodium lauryl sulfate, and sodium cocoyl hydroxyethanesulfonate is 15:10:15:5.

[0029] This invention uses the above four surfactants in a specific dosage ratio range to form a compound. The components complement each other, so that the shampoo and conditioner particles can effectively clean the hair and scalp, while avoiding the irritation and dryness that may be caused by a single surfactant. This achieves a gentle and deep cleaning effect. Furthermore, the compound of the four components can synergistically improve the richness, stability and fineness of the foam, and maintain a good rinsing effect after using the shampoo and conditioner particles, avoiding incomplete rinsing and thus providing users with a better user experience.

[0030] Preferably, the filler comprises at least one of modified corn starch, microcrystalline cellulose, and polyvinyl alcohol; and / or, the anti-caking agent comprises magnesium stearate or silicon dioxide; and / or, the humectant comprises at least one of sodium hyaluronate, trehalose, and sorbitol; and / or, the pH adjuster comprises citric acid; and / or, the fragrance comprises a flavoring.

[0031] Secondly, the present invention provides the application of the preparation method in the preparation of personal care products, which include shampoo, body wash and facial cleansing products.

[0032] The preparation method described in this invention can be widely applied to the preparation of solid granule personal care products such as shampoos, facial cleansers, or bath products. The method can minimize the water activity of the granules and improve their performance. It can effectively ensure the long-term stability of the granules without the need for preservatives and effectively avoid skin irritation and allergic reactions caused by preservatives. It is suitable for all skin types, especially sensitive skin.

[0033] Thirdly, the present invention provides a low water activity, preservative-free shampoo and conditioner granule, wherein the shampoo and conditioner granule comprises the shampoo and conditioner granules prepared by the above-described preparation method, as well as a hair conditioning agent and a softener.

[0034] Preferably, the softener includes at least one of argan kernel oil, jojoba seed oil, and coconut oil; the hair conditioner includes lactobacillus / rye flour fermentation product.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] (1) This invention innovatively develops a solid washing and care granule using a specific preparation process. By precisely controlling the parameters of each important factor in the process, it can ensure the formation of an ideal granule structure and uniform particle size distribution, effectively improve the mechanical strength of the granules, reduce the risk of granules being easily damaged or broken during storage or transportation, and significantly reduce the water activity of the granules, thereby ensuring the quality, stability and overall performance of the preservative-free granules. They are also easy to rinse and leave no residue, which can significantly reduce the water consumption during use, reduce water resource consumption, and greatly reduce the volume, making them easy to transport or carry.

[0037] (2) The present invention uses specific surface surfactants and thickeners in combination with other ingredients to prepare washing and care granules. The components work together to effectively achieve the gentle and deep cleaning effect of washing and care granules, and synergistically improve the richness, stability and fineness of foam. At the same time, it improves the structure and performance of granules to further improve the long-term stability of granules and maintain the good rinsing effect after use of washing and care granules, effectively improving the user experience. Attached Figure Description

[0038] Figure 1 The appearance of the shampoo and conditioner granules prepared in Example 1 (A) and Comparative Example 1 (B) is shown. Detailed Implementation

[0039] To better illustrate the objectives, technical solutions, and advantages of this invention, the invention will be further described below with reference to specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0040] Unless otherwise specified, all raw materials used in the following examples and comparative examples are commercially available and commonly used materials. Experimental procedures not specifically described are standard procedures in the art or can be understood or known by those skilled in the art based on their prior knowledge or common general knowledge.

[0041] Example 1

[0042] This embodiment 1 provides a method for preparing low water activity, preservative-free cleaning and conditioning granules, the preparation method comprising the following steps:

[0043] S1. Take the following raw materials in parts by weight: 15 parts hexadecyltrimethylammonium chloride, 10 parts cocamidopropyl betaine, 15 parts sodium lauryl sulfate, 5 parts sodium cocoyl ethoxylate, 12 parts modified corn starch, 3 parts magnesium stearate, 1 part sodium hyaluronate, 9 parts trehalose, 5 parts sorbitol, 0.001 parts lactobacillus / rye flour fermentation product, 0.001 parts argan kernel oil, 0.001 parts jojoba seed oil, 0.001 parts coconut oil, 0.5 parts citric acid, and 1 part daily fragrance. Mix the weighed raw materials evenly, dry them, and pulverize them into powder.

[0044] S2. Weigh hydroxypropyl methylcellulose, xanthan gum, and chitosan, and mix the raw materials with water to prepare a thickener aqueous solution with a mass concentration of 0.5%. The mass ratio of hydroxypropyl methylcellulose, xanthan gum, and chitosan is 0.5:0.3:0.2.

[0045] S3. Add the powder described in step S1 to the granulator, then spray the thickener aqueous solution described in step S2 into the granulator, and then use a peristaltic pump to evenly spray the thickener aqueous solution into the granulator. Control the air temperature of the air blown into the granulator by the blower at 85°C and the blower speed at 15Hz, so that the powder can turn over in the granulator and fully contact the sprayed aqueous solution to produce granules. Control the outlet air temperature of the granulator at 30°C and the humidity at 30%.

[0046] S4. Screen particles with a mesh size of (10-100) to be used as cleaning and conditioning granules for the finished product.

[0047] In step S3, the mass ratio of the thickener aqueous solution to the powder is 0.3:1.

[0048] Example 2

[0049] This embodiment provides a method for preparing low water activity, preservative-free shampoo and conditioner granules. The raw materials for preparing the granules are the same as those in Example 1. The preparation method includes the following steps:

[0050] S1. Weigh out the same raw materials as in Example 1, except for the thickener, and mix them evenly. Dry them and pulverize them into powder.

[0051] S2. Weigh the thickener raw materials and mix them with water to prepare a thickener aqueous solution with a mass concentration of 0.7%. The mass ratio of hydroxypropyl methylcellulose, xanthan gum and chitosan in the thickener is 1:0.1:0.1.

[0052] S3. Add the powder described in step S1 to the granulator, then spray the thickener aqueous solution described in step S2 into the granulator, and then use a peristaltic pump to evenly spray the thickener aqueous solution into the granulator. Control the air temperature of the air blown into the granulator by the blower at 80℃ and the blower speed at 50HZ so that the powder can turn over in the granulator and fully contact the sprayed aqueous solution to produce granules. Control the outlet air temperature of the granulator below 50℃ and the humidity at 20%.

[0053] S4. Screen particles with a mesh size of (10-100) to be used as cleaning and conditioning granules for the finished product.

[0054] In step S3, the mass ratio of the thickener aqueous solution to the powder is 0.2:1.

[0055] Example 3

[0056] This embodiment provides a method for preparing low water activity, preservative-free shampoo and conditioner granules. The raw materials for preparing the granules are the same as those in Example 1. The preparation method includes the following steps:

[0057] S1. Weigh out the same raw materials as in Example 1, except for the thickener, and mix them evenly. Dry them and pulverize them into powder.

[0058] S2. Weigh the thickener raw materials and mix them with water to prepare a thickener aqueous solution with a mass concentration of 0.3%. The mass ratio of hydroxypropyl methylcellulose, xanthan gum and chitosan in the thickener is 0.1:0.5:0.3.

[0059] S3. Add the powder described in step S1 to the granulator, then spray the thickener aqueous solution described in step S2 into the granulator, and then use a peristaltic pump to evenly spray the thickener aqueous solution into the granulator. Control the air temperature blown into the granulator by the blower at 90℃ and the blower speed at 50HZ so that the powder can turn over in the granulator and fully contact the sprayed aqueous solution to produce granules. Control the outlet air temperature of the granulator below 50℃ and the humidity at 40%.

[0060] S4. Screen particles with a mesh size of (10-100) to be used as cleaning and conditioning granules for the finished product.

[0061] In step S3, the mass ratio of the thickener aqueous solution to the powder is 0.4:1.

[0062] Example 4

[0063] This embodiment 1 provides a method for preparing low water activity preservative-free shampoo and conditioner granules. The only difference between this embodiment and Embodiment 1 is the raw materials. The raw materials for preparing the shampoo and conditioner granules in this embodiment include the following components in parts by weight: 5 parts hexadecyltrimethylammonium chloride, 5 parts cocamidopropyl betaine, 10 parts sodium lauryl sulfate, 2 parts sodium cocoyl ethanesulfonate, 10 parts modified corn starch, 1 part magnesium stearate, 0.1 parts sodium hyaluronate, 1 part trehalose, 1 part sorbitol, 0.0005 parts lactobacillus / rye flour fermentation product, 0.0005 parts argan kernel oil, 0.0005 parts jojoba seed oil, 0.0005 parts coconut oil, 0.1 parts citric acid, and 0.5 parts daily fragrance. The thickener components and dosages, as well as the preparation process conditions, are the same as in Embodiment 1.

[0064] Example 5

[0065] This embodiment 1 provides a method for preparing low water activity preservative-free shampoo and conditioner granules. The only difference between this embodiment and Embodiment 1 is the raw materials. The raw materials for preparing the shampoo and conditioner granules in this embodiment include the following components in parts by weight: 20 parts hexadecyltrimethylammonium chloride, 15 parts cocamidopropyl betaine, 20 parts sodium lauryl sulfate, 6 parts sodium cocoyl ethanesulfonate, 15 parts modified corn starch, 5 parts magnesium stearate, 1 part sodium hyaluronate, 10 parts trehalose, 10 parts sorbitol, 0.0015 parts lactobacillus / rye flour fermentation product, 0.0015 parts argan kernel oil, 0.0015 parts jojoba seed oil, 0.0015 parts coconut oil, 1 part citric acid, and 1.5 parts daily fragrance. The thickener components and dosages, as well as the preparation process conditions, are the same as in Embodiment 1.

[0066] Comparative Example 1

[0067] This comparative example provides a method for preparing low water activity preservative-free cleaning and care granules, which differs from Example 1 only in that: the mass concentration of the thickener in the thickener aqueous solution is 0.1%, and the mass ratio of hydroxypropyl methylcellulose, xanthan gum and chitosan in the thickener is 0.5:0.3:0.2; the other raw materials, dosages and preparation process conditions are the same as in Example 1.

[0068] Comparative Example 2

[0069] This comparative example provides a method for preparing low water activity preservative-free cleaning and conditioning granules. The only difference between this method and Example 1 is that the mass concentration of the thickener in the thickener aqueous solution is 1%, and the mass ratio of hydroxypropyl methylcellulose, xanthan gum, and chitosan in the thickener is 0.5:0.3:0.2. All other raw materials, dosages, and preparation process conditions are the same as in Example 1.

[0070] Comparative Example 3

[0071] This comparative example provides a method for preparing low water activity, non-corrosion cleaning and care granules. The only difference between this method and Example 1 is that in step S3, the air temperature in the granulator is controlled at 70°C; the raw materials, dosages, and other preparation process conditions are the same as in Example 1.

[0072] Comparative Example 4

[0073] This comparative example provides a method for preparing low water activity, non-corrosion cleaning and care granules. The only difference between this method and Example 1 is that in step S3, the air temperature in the granulator is controlled at 100°C; the raw materials, dosages, and other preparation process conditions are the same as in Example 1.

[0074] Comparative Example 5

[0075] This comparative example provides a method for preparing low water activity, non-corrosive cleaning and care granules. The only difference between this method and Example 1 is that the mass ratio of the thickener aqueous solution to the powder is 0.1:1, and the speed of the blower is controlled at 5Hz. All other aspects are the same as in Example 1.

[0076] Comparative Example 6

[0077] This comparative example provides a method for preparing low water activity, non-corrosive cleaning and care granules. The only difference between this method and Example 1 is that the mass ratio of the thickener aqueous solution to the powder is 0.6:1, and the speed of the blower is controlled at 60Hz. All other aspects are the same as in Example 1.

[0078] Comparative Example 7

[0079] This comparative example provides a method for preparing low water activity, non-corrosion cleaning and care granules. The only difference between this method and Example 1 is that in step S3, the outlet air temperature of the granulator is controlled at 60°C and the humidity is controlled at 50%. All other aspects are the same as in Example 1.

[0080] Comparative Example 8

[0081] This comparative example provides a method for preparing low water activity, non-corrosion-resistant cleaning and conditioning granules. The difference between this method and Example 1 is that the thickener is directly mixed with the remaining raw materials, dried, pulverized into powder, and then the powder is added to a granulator. A peristaltic pump is then used to uniformly spray deionized water into the granulator for granulation. The mass ratio of deionized water to powder is 0.3:1. The raw materials, dosages, and other preparation process conditions are the same as in Example 1.

[0082] Comparative Example 9

[0083] This comparative example provides a method for preparing low water activity preservative-free cleaning and conditioning granules. The difference between this method and Example 1 is that water-soluble polysaccharide trehalose is used to replace the thickener and is mixed with water to prepare a trehalose aqueous solution with a mass concentration of 0.5%. The trehalose aqueous solution is then sprayed and granulated. The remaining raw materials, dosages, and other preparation process conditions are the same as in Example 1.

[0084] Comparative Example 10

[0085] This comparative example provides a method for preparing low water activity preservative-free washing and care granules. The difference between this method and Example 1 is that the raw materials are different. Xanthan gum and chitosan are missing in this comparative example, and the thickener is only hydroxypropyl methylcellulose. The other raw materials, dosages, and preparation process conditions are the same as in Example 1.

[0086] Comparative Example 11

[0087] This comparative example provides a method for preparing low water activity preservative-free washing and care granules. The difference between this method and Example 1 is that the raw materials are different. Hydroxypropyl methylcellulose and chitosan are missing in this comparative example, and the thickener is only xanthan gum. The other raw materials, dosages, and preparation process conditions are the same as in Example 1.

[0088] Comparative Example 12

[0089] This comparative example provides a method for preparing low water activity preservative-free washing and conditioning granules. The difference between this method and Example 1 is that the raw materials are different. This comparative example omits hexadecyltrimethylammonium chloride and sodium cocoyl hydroxyethanesulfonate. The amount of surfactant remains unchanged, that is, the weight parts of cocamidopropyl betaine are increased to 20 parts and the weight parts of sodium lauryl sulfate are increased to 25 parts. The remaining raw materials, amounts, and preparation process conditions are the same as in Example 1.

[0090] Comparative Example 13

[0091] This comparative example provides a method for preparing low water activity preservative-free washing and conditioning granules, which differs from Example 1 in that the raw materials are different. Cocamidopropyl betaine and sodium lauryl sulfate are omitted in this comparative example, while the amount of surfactant remains unchanged, that is, the weight parts of hexadecyltrimethylammonium chloride are increased to 30 parts and the weight parts of sodium cocoyl hydroxyethanesulfonate are increased to 15 parts; the remaining raw materials, amounts, and preparation process conditions are the same as in Example 1.

[0092] Example of effect

[0093] 1. Tests on particle appearance, particle hardness, and dissolution rate:

[0094] The shampoo and conditioner granules prepared in Examples 1-5 and Comparative Examples 1-13 were used as samples for appearance observation, granule hardness, and dissolution rate testing. The specific method for the dissolution rate test is as follows: 2g of the same mass of granule sample was weighed and placed in 100mL of the same volume of deionized water. The mixture was continuously stirred using a stirrer at a speed of 50r / min. The time required for the sample to completely dissolve in the water was measured to evaluate its dissolution rate. The hardness of the shampoo and conditioner granules was tested using a hardness tester, and the hardness value (P value) was recorded in N. The specific measurement method can be found in the 2005 edition of the Chinese Pharmacopoeia. The specific results are shown in Table 3.

[0095] Table 3

[0096]

[0097]

[0098]

[0099] As shown in Table 3, the shampoo and conditioner granules prepared by the technical solution of the present invention are uniform in size and have relatively high hardness, which can effectively avoid the problem of breakage and cracking of granules during transportation or storage. Furthermore, the shampoo and conditioner granules have good solubility and can dissolve quickly during use. In particular, the shampoo and conditioner granules prepared in Example 1 have the best hardness and solubility. However, in Comparative Examples 1-9, because the preparation process parameters exceeded the limits of the present invention, the resulting shampoo and conditioner granules were not uniform in size, and there was adhesion between the granules, which is not conducive to actual production applications. Compared with the examples, the granule hardness was significantly reduced, the granule structure was looser, and the solubility was not improved. In Comparative Examples 10-11, due to the absence of any two components in hydroxypropyl methylcellulose, xanthan gum, and chitosan, the granule structure could not be effectively improved, resulting in a certain degree of decrease in granule hardness and a significant decrease in solubility.

[0100] Figure 1(AB) are images of the appearance of the shampoo and conditioner granules prepared in Example 1 and Comparative Example 1, respectively. As can be seen from the images, the shampoo and conditioner granules prepared in Example 1 of the present invention are uniform in size, have a complete structure and high hardness, while the shampoo and conditioner granules prepared in Comparative Example 1 have uneven particle distribution, different particle sizes, and a loose and fragile structure, which is not conducive to the storage and transportation of the shampoo and conditioner granules.

[0101] 2. Water activity test:

[0102] The shampoo and conditioner granules prepared in Example 1 and Comparative Examples 1-13 were used as samples, and their water activity was tested. The specific test method referred to the United States Pharmacopeia-National Formulary General Chapter 922 Water Activity, and a water activity meter was used for testing. The specific results are shown in Table 4.

[0103] Table 4

[0104] Example 1 0.29 Comparative Example 5 0.74 Comparative Example 10 0.56 Comparative Example 1 0.76 Comparative Example 6 0.68 Comparative Example 11 0.58 Comparative Example 2 0.65 Comparative Example 7 0.76 Comparative Example 12 0.59 Comparative Example 3 0.85 Comparative Example 8 0.82 Comparative Example 13 0.61 Comparative Example 4 0.73 Comparative Example 9 0.71

[0105] Water activity has a significant impact on the properties, stability, and effectiveness of a product. Generally speaking, solid shampoo and conditioner granules with lower water activity are more likely to improve product stability, prevent the degradation or inactivation of active ingredients, and help control foam generation, resulting in more stable foam quantity and quality. This makes the solid shampoo and conditioner granules more uniform, easier to rinse, and leaves no residue during use.

[0106] As shown in Table 4, the shampoo and conditioner granules prepared by the technical solution of the present invention can achieve a relatively low water activity. In particular, the water activity of the shampoo and conditioner granules prepared in Example 1 reaches 0.29, which can fully guarantee the stability and overall performance of the shampoo and conditioner granules, and achieve the anti-corrosion effect without the addition of preservatives. In contrast, the water activity of the shampoo and conditioner granules in Comparative Examples 1-7 is more significantly increased when the preparation process conditions of the shampoo and conditioner granules exceed the preferred range of the present invention. In Comparative Example 8, the water activity of the shampoo and conditioner granules is significantly increased when the thickener is directly mixed with the other raw materials, and in Comparative Example 9, the water activity of the shampoo and conditioner granules prepared by using trehalose, which also has adhesive properties, instead of the thickener of the present invention, is significantly increased. In Comparative Examples 12-13, when the specific surfactant component is missing or replaced, the water activity of the shampoo and conditioner granules prepared by the examples is increased to a certain extent compared with the examples.

[0107] 3. Product performance evaluation test:

[0108] The shampoo and conditioner granules prepared in Examples 1-5 and Comparative Examples 12-13 were used as samples for sensory evaluation testing.

[0109] Seventy participants aged 20-60 years with normal skin were randomly selected, including 10 men and 60 women. The participants were randomly divided into 7 groups of 10 each. Each group tried the solid shampoo granules from Examples 1-5 and Comparative Examples 12-13, and evaluated their shampooing experience. Each sample was used for two weeks. Participants rated the samples based on their experience, including hair cleaning and stain removal, foam richness, and ease of rinsing with no residue. A 10-point scale was used, with 1 being the worst and 10 the best. The evaluation results are shown in Table 5, where a higher average score indicates a better effect.

[0110] Table 5

[0111]

[0112] As shown in Table 5, the washing and care granules prepared by the technical solution of the present invention achieve a balance in terms of cleaning ability, foam stability and easy rinsing in practical applications, and can provide users with a more ideal user experience.

[0113] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing low water activity, preservative-free cleaning and conditioning granules, characterized in that, The preparation method includes the following steps: S1. Take the following raw materials by weight: 22-61 parts surfactant, 10-15 parts filler, 1-5 parts anti-caking agent, 2.1-21 parts humectant, 0.1-1 part pH adjuster and 0.5-1.5 parts fragrance. Mix the weighed raw materials evenly, dry them, and pulverize them into powder. S2. Weigh the thickener and mix it with water to prepare a thickener aqueous solution; S3. Add the powder described in step S1 to the granulator, and then spray the thickener aqueous solution described in step S2 into the granulator. Control the air temperature in the granulator to 80-90℃ to produce granules, thus obtaining the washing and care granules. The mass concentration of the thickener in the aqueous thickener solution is 0.3-0.7%; The thickener is hydroxypropyl methylcellulose, xanthan gum, and chitosan; The surfactant is hexadecyltrimethylammonium chloride, cocamidopropyl betaine, sodium lauryl sulfate, and sodium cocoyl ethanesulfonate. The outlet air temperature of the granulator is controlled below 50℃, and the humidity is controlled between 20-40%.

2. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of the thickener aqueous solution to the powder is (0.2-0.4):

1.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the thickener aqueous solution to the powder is 0.3:

1.

4. The preparation method according to claim 1, characterized in that, In step S3, a blower is used to control the air temperature in the granulator, and the speed of the blower is controlled at 15-50Hz.

5. The preparation method according to claim 1, characterized in that, The mass concentration of the thickener in the aqueous thickener solution is 0.5%.

6. The preparation method according to claim 1, characterized in that, In step S1, the raw materials for preparing the preservative-free washing and care granules include the following components in parts by weight: 45 parts surfactant, 12 parts filler, 3 parts anti-caking agent, 15 parts humectant, 0.5 parts pH adjuster, and 1 part fragrance.

7. The preparation method according to claim 1, characterized in that, The mass ratio of hydroxypropyl methylcellulose, xanthan gum, and chitosan is (0.1-1):(0.1-0.5):(0.1-0.3).

8. The preparation method according to claim 7, characterized in that, The mass ratio of hydroxypropyl methylcellulose, xanthan gum, and chitosan is 0.5:0.3:0.

2.

9. The preparation method according to claim 1 or 6, characterized in that, The mass ratio of hexadecyltrimethylammonium chloride, cocamidopropyl betaine, sodium lauryl sulfate and sodium cocoyl hydroxyethyl sulfonate is (5-20):(5-15):(10-20):(2-6).

10. The preparation method according to claim 1 or 6, characterized in that, The filler includes at least one of modified corn starch, microcrystalline cellulose, and polyvinyl alcohol; and / or, the anti-caking agent includes magnesium stearate or silicon dioxide; and / or, the humectant includes at least one of sodium hyaluronate, trehalose, and sorbitol; and / or, the pH adjuster includes citric acid; and / or, the fragrance includes flavoring.

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