Anti-aging, face-beautifying and skin-care composition and preparation method thereof
By using the combination of Centella asiatica extract, sodium hyaluronate, grape seed extract, vitamin C, ceramide, ginseng root extract and green tea extract in anti-aging and beautifying skin care products, combined with the precise and optimized preparation process, the problems of insufficient synergistic components of the existing product and extensive preparation process are solved, and efficient, stable and long-lasting anti-aging and beautifying effects are achieved.
Patent Information
- Application Number
- CN202510096478.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-22
- Publication Date
- 2025-05-13
AI Technical Summary
The existing anti-aging skin care products have shortcomings in terms of ingredient coordination, which is difficult to attack skin aging in multiple dimensions, and the preparation process is extensive, resulting in the loss or inactivation of key active ingredients, which cannot meet consumers' demand for efficient, stable and long-lasting anti-aging and beauty skin care products.
An anti-aging beauty and skin care composition is adopted, which includes Centella asiatica extract, sodium hyaluronate, grape seed extract, vitamin C, ceramide, ginseng root extract and green tea extract. Through precise optimization of the preparation process, the ingredient activity and structure are ensured.
This composition provides a tough barrier and deep nourishment through the synergistic effect of Centella asiatica and ceramide; antioxidant effects of grape seeds and vitamin C block dullness; the synergistic effect of sodium hyaluronate and ginseng root and green tea extract is moisturized and revitalized, achieving a comprehensive anti-aging effect, outstanding stability, adapting to high and low temperature environments, extending shelf life, and reducing the risk of spoilage.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of cosmetics, and in particular to an anti-aging beauty and skin care composition and a preparation method thereof. Background Art
[0002] Skin aging is affected by the interaction of endogenous and exogenous factors, which causes a series of aging symptoms such as wrinkle proliferation, loss of elasticity, rough texture, dull color, and moisture loss, which seriously damage the beauty and function of the skin.
[0003] There are many anti-aging skin care products on the market, but each has its own defects. Traditional skin care products often focus on a single anti-aging path, or simply moisturize, or only anti-oxidize. The ingredients are not synergistic, and it is difficult to attack skin aging in multiple dimensions. For example, some products only rely on hyaluronic acid for moisturizing, ignoring the stimulation of cell vitality and the promotion of metabolism. They are more than enough for short-term hydration but insufficient for long-term anti-aging. It is difficult to improve complex aging problems such as wrinkles, sagging, dullness, etc. from the root. In addition, the preparation process is extensive and the extraction technology is simple, resulting in the loss or inactivation of key active ingredients, which cannot meet consumers' urgent demands for efficient, stable and long-lasting anti-aging beauty skin care products.
[0004] Therefore, developing natural, safe, synergistic, efficient and stable anti-aging skin care compositions has become a key mission in the cosmetics field. Summary of the invention
[0005] The main purpose of the present invention is to provide an anti-aging beauty skin care composition and a preparation method thereof, which can effectively solve the problems in the background technology.
[0006] To achieve the above object, the technical solution adopted by the present invention is: An anti-aging beauty skin care composition and a preparation method thereof. The composition comprises, by weight, 1 to 10 parts of Centella asiatica extract, 0.5 to 5 parts of sodium hyaluronate, 0.5 to 5 parts of grape seed extract, 0.1 to 2 parts of vitamin C, 0.5 to 3 parts of ceramide, 1 to 8 parts of ginseng root extract, and 1 to 6 parts of green tea extract.
[0007] Preferably, 2-8 parts of Centella asiatica extract, 1-4 parts of sodium hyaluronate, 1-4 parts of grape seed extract, 0.5-1.5 parts of vitamin C, 1-2.5 parts of ceramide, 2-6 parts of ginseng root extract, and 2-5 parts of green tea extract.
[0008] Preferably, 5 parts of Centella asiatica extract, 2.5 parts of sodium hyaluronate, 2 parts of grape seed extract, 1 part of vitamin C, 1.5 parts of ceramide, 4 parts of ginseng root extract, and 3 parts of green tea extract.
[0009] A method for preparing the above anti-aging beauty skin care composition, the specific steps are as follows: Step 1: Wash and dry Centella asiatica, extract with 70% to 80% ethanol at a solid-liquid ratio of 1:8 to 1:12, reflux at 50 to 60°C for 2 to 3 times, each time for 1.5 to 2 hours, filter and concentrate to obtain the extract for later use; Step 2: Select medical grade or cosmetic grade sodium hyaluronate powder, pass it through an 80-100 mesh sieve to remove possible impurities such as lumps, and place it in a dry, cool, ventilated place for later use; Step 3: Purchase high-quality grape seeds, wash and crush them into 20-40 mesh size particles, use supercritical CO2 extraction technology, set the extraction pressure to 25-35MPa, the temperature to 40-50°C, and the extraction time to 1.5-2.5 hours, collect the extracted grape seed extract, place it in a sealed container, and store it at a low temperature of 0-5°C away from light for later use; Step 4: Select L-type vitamin C crystals with a purity of more than 99%. To prevent oxidation, seal and store them in a dry, dark environment below 25°C before use; Step 5: Choose cosmetic-grade ceramide raw materials, which are usually purchased in the form of liposomes to ensure better stability and skin permeability; Step 6: Wash and slice the ginseng roots, boil and extract at 80-90°C, with a solid-liquid ratio of 1:10-1:15, 2-3 times, then precipitate with alcohol, filter and concentrate for later use; Step 7: Select high-quality green tea leaves, crush them to a fineness of 30-50 mesh, and extract them 2-3 times with 80-90°C hot water at a material-liquid ratio of 1:10-1:15, combine and filter, then spray-dry into powder for later use; Step 8: Premixing: Accurately weigh each ingredient according to the formula, place it in a clean, sterile stainless steel mixing tank with a stirring device, start low-speed stirring at 100-200 rpm for 5-10 minutes to preliminarily mix the ingredients evenly; Step 9: Heating and homogenizing: Turn on the heating device of the mixing tank and slowly raise the temperature to 60-70°C. At this temperature, switch to high-speed stirring at a speed of 800-1200 rpm. Simultaneously start the homogenizer at a homogenizing pressure of 20-30 MPa. Homogenize the mixture for 10-15 minutes to form a uniform colloidal mixture. Step 10: Cooling and filtration: After homogenization, turn off the heating device, cool the mixture in the mixing tank by circulating cooling water in the jacket to 30-40°C, and filter the mixture using a sterilizing filter with a filtration accuracy of 0.22-0.45 μm to obtain a clear, sterile anti-aging beauty and skin care composition; Step 11: Packaging and storage: The filtered composition is filled into pre-sterilized skin care product packaging containers through automated filling equipment. After sealing, the containers are stored in a cool, dry and ventilated warehouse environment.
[0010] Preferably, in the premixing step, each component is pretreated before being added to the mixing tank, wherein the Centella asiatica extract is extracted and concentrated, the sodium hyaluronate is sieved, the grape seed extract is subjected to supercritical CO2 extraction and preservation, the vitamin C is sealed and preserved, the ceramide is pretreated by liposome encapsulation, the ginseng root extract is boiled, precipitated and concentrated, and the green tea extract is crushed, leached and spray-dried.
[0011] Preferably, in the heating and homogenizing step, the heating rate is controlled at 1 to 2° C. per minute.
[0012] Preferably, in the packaging and storage step, the skin care product packaging container is sterilized by ultraviolet irradiation or high-temperature steam sterilization, the temperature of the warehouse environment is controlled at 15-25°C, and the relative humidity is controlled at 40%-60%.
[0013] Compared with the prior art, the present invention has the following beneficial effects: Centella asiatica and ceramide build a strong barrier and deeply nourish; grape seeds and vitamin C are strong antioxidants and prevent dullness; sodium hyaluronate cooperates with ginseng root and green tea extract to moisturize and revitalize. All ingredients work closely together to fight against aging in all directions, and the effect is far better than the simple addition of a single ingredient. In terms of preparation technology, precise optimization parameters are used to improve the purity and yield of active ingredients. Supercritical CO2 extraction and other technologies protect the activity and structure of ingredients to ensure excellent quality and outstanding overall stability. The rigorous process and exquisite formula make the product lastingly stable in high and low temperature environments, maintain the appearance, texture and activity, extend the shelf life, and reduce the risk of deterioration. DETAILED DESCRIPTION
[0014] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0015] Example 1 Step 1: Wash and dry Centella asiatica, extract with 70% ethanol at a solid-liquid ratio of 1:12, reflux at 60°C for 3 times, each time for 2 hours, filter and concentrate to obtain the extract for later use; Step 2: Select medical or cosmetic grade sodium hyaluronate powder, pass it through a 90-mesh sieve to remove possible impurities such as lumps, and place it in a dry, cool, ventilated place for later use; Step 3: Purchase high-quality grape seeds, wash and crush them into 30 mesh particles, use supercritical CO2 extraction technology, set the extraction pressure to 30MPa, the temperature to 45°C, and the extraction time to 2 hours, collect the extracted grape seed extract, place it in a sealed container, and store it at 3°C away from light for later use; Step 4: Select L-type vitamin C crystals with a purity of more than 99%. To prevent oxidation, seal and store them in a dry, dark environment below 25°C before use; Step 5: Choose cosmetic-grade ceramide raw materials, which are usually purchased in the form of liposomes to ensure better stability and skin permeability; Step 6: Wash and slice the ginseng roots, boil and extract (85°C, material-liquid ratio 1:15, 3 times), then precipitate with alcohol, filter and concentrate for later use; Step 7: Select high-quality green tea leaves, grind them to 40 mesh fineness, extract them three times with 85°C hot water at a material-liquid ratio of 1:12, combine and filter, spray-dry into powder for later use; Step 8: Premixing: Accurately weigh each ingredient according to the formula, place it in a clean, sterile stainless steel mixing tank with a stirring device, start low-speed stirring (speed is 150 rpm), stir for 7 minutes to make the ingredients preliminarily mixed; Step 9: Heating and homogenizing: Turn on the heating device of the mixing tank and slowly raise the temperature to 65°C. At this temperature, switch to high-speed stirring (speed of 1000 rpm) and start the homogenizer (homogenizing pressure of 25 MPa) at the same time. Homogenize the mixture for 12 minutes to form a uniform colloidal mixture; Step 10: Cooling and filtration: After homogenization, turn off the heating device, cool the mixture in the preparation tank by circulating cooling water in the jacket, and cool it down to 35°C. Filter the mixture with a sterilizing filter with a filtration accuracy of 0.45 μm to obtain a clear, sterile anti-aging beauty and skin care composition; Step 11: Packaging and storage: Fill the filtered composition into a pre-sterilized skin care product packaging container through an automated filling device, seal the package, and store it in a cool, dry, and ventilated warehouse environment; Step 12: Accurately weigh 10 parts of Centella asiatica extract, 5 parts of sodium hyaluronate, 5 parts of grape seed extract, 2 parts of vitamin C, 3 parts of ceramide, 8 parts of ginseng root extract, and 6 parts of green tea extract according to the ratio and put them into a container, add 9 times the volume of deionized water, and mix evenly to obtain the anti-aging beauty skin care composition.
[0016] The "mesh" mentioned above is a key unit for measuring particle size in the field of crushed particles. The number of holes on the sieve per square inch. The larger the mesh number, the smaller the aperture of the sieve, and the finer the particle size passing through the sieve.
[0017] The composition in Example 1 is in a light yellow uniform colloid state. After being stored at 40°C and -15°C for 3 months, it is normal when restored to room temperature. It has good stability, a DPPH free radical scavenging rate of 85%, and good antioxidant properties. After use, skin moisture is increased by 30% within 8 hours, and the depth of facial wrinkles can be reduced by an average of 0.05mm in 28 days, with significant anti-aging and beauty effects.
[0018] Example 2 In this embodiment, the content of each extract is adjusted on the basis of the embodiment 1, as follows: 3 parts of Centella asiatica extract, 1.5 parts of sodium hyaluronate, 1.5 parts of grape seed extract, 0.8 parts of vitamin C, 1 part of ceramide, 3 parts of ginseng root extract, and 2.5 parts of green tea extract.
[0019] Example 3 In this embodiment, the content of each extract is adjusted on the basis of the embodiment 1, as follows: 7 parts of Centella asiatica extract, 3.5 parts of sodium hyaluronate, 3 parts of grape seed extract, 1.2 parts of vitamin C, 2 parts of ceramide, 5 parts of ginseng root extract, and 4 parts of green tea extract.
[0020] Example 4 In this embodiment, the content of each extract is adjusted on the basis of the embodiment 1, as follows: 2 parts of Centella asiatica extract, 1 part of sodium hyaluronate, 1 part of grape seed extract, 0.5 parts of vitamin C, 0.8 parts of ceramide, 2 parts of ginseng root extract, and 2 parts of green tea extract.
[0021] Example 5 In this embodiment, the content of each extract is adjusted on the basis of the embodiment 1, as follows: 8 parts of Centella asiatica extract, 4 parts of sodium hyaluronate, 4 parts of grape seed extract, 1.5 parts of vitamin C, 2.5 parts of ceramide, 6 parts of ginseng root extract, and 5 parts of green tea extract.
[0022] Example 6 In this embodiment, the content of each extract is adjusted on the basis of the embodiment 1, as follows: 1 part of Centella asiatica extract, 0.5 part of sodium hyaluronate, 0.5 part of grape seed extract, 0.1 part of vitamin C, 0.5 part of ceramide, 1 part of ginseng root extract, and 1 part of green tea extract.
[0023] Comparative Example 1 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: 2.5 parts of sodium hyaluronate, 2 parts of grape seed extract, 1 part of vitamin C, 1.5 parts of ceramide, 4 parts of ginseng root extract, 3 parts of green tea extract. This comparative example does not add Centella asiatica extract.
[0024] Comparative Example 2 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: 5 parts of Centella asiatica extract, 2 parts of grape seed extract, 1 part of vitamin C, 1.5 parts of ceramide, 4 parts of ginseng root extract, 3 parts of green tea extract. Sodium hyaluronate is not added in this comparative example.
[0025] Comparative Example 3 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: 5 parts of Centella asiatica extract, 2.5 parts of sodium hyaluronate, 1 part of vitamin C, 1.5 parts of ceramide, 4 parts of ginseng root extract, 3 parts of green tea extract. Grape seed extract is not added in this comparative example.
[0026] Comparative Example 4 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: 5 parts of Centella asiatica extract, 2.5 parts of sodium hyaluronate, 2 parts of grape seed extract, 1.5 parts of ceramide, 4 parts of ginseng root extract, and 3 parts of green tea extract. Vitamin C is not added in this comparative example.
[0027] Comparative Example 5 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: 5 parts of Centella asiatica extract, 2.5 parts of sodium hyaluronate, 2 parts of grape seed extract, 1 part of vitamin C, 4 parts of ginseng root extract, 3 parts of green tea extract. No ceramide is added in this comparative example.
[0028] Comparative Example 6 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: 5 parts of Centella asiatica extract, 2.5 parts of sodium hyaluronate, 2 parts of grape seed extract, 1 part of vitamin C, 1.5 parts of ceramide, 3 parts of green tea extract. No ginseng root extract is added in this comparative example.
[0029] Comparative Example 7 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: 5 parts of Centella asiatica extract, 2.5 parts of sodium hyaluronate, 2 parts of grape seed extract, 1 part of vitamin C, 1.5 parts of ceramide, 4 parts of ginseng root extract. In this comparative example, no green tea extract is added.
[0030] Comparative Example 8 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: This comparative example uses 5 parts of Centella asiatica extract alone.
[0031] Comparative Example 9 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: This comparative example uses 2.5 parts of sodium hyaluronate alone.
[0032] Comparative Example 10 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: This comparative example uses 2 portions of grape seed extract alone.
[0033] Comparative Example 11 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: This comparative example uses 1 part of vitamin C alone.
[0034] Comparative Example 12 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: In this comparative example, 1.5 parts of ceramide was used alone.
[0035] Comparative Example 13 In this comparative example, the content of each extract is adjusted on the basis of Example 1, as follows: In this comparative example, 4 portions of ginseng root extract were used alone.
[0036] The anti-wrinkle effect of the anti-aging beauty skin care composition in Examples 1-6 and Comparative Examples 1-14 was investigated, and a large number of volunteers were screened and randomly divided into groups based on age, skin quality, and wrinkle condition to ensure that the initial skin conditions between groups were balanced and comparable, and the number of people in each group was sufficient for statistical power.
[0037] The example group used the composition of the present invention, and the comparative group used the product with specific ingredients. They were all applied to specific facial areas in a standardized manner, with a unified daily application frequency, amount and duration, and were strictly recorded. Wrinkle depth was measured with a high-precision instrument, which was calibrated before measurement. Multiple measurements were taken at multiple locations such as the eye area, forehead, and corners of the mouth to obtain the average as the baseline. The measurement was repeated after a specified number of weeks, and the difference was calculated to an accuracy of 0.001mm. Skin elasticity was measured by lightly touching the cheek with a professional tester, and the elastic modulus was obtained by transmitting and receiving signals. The rate of change was calculated according to the formula after multiple average measurements. Crow's feet improvement was scored by a professional physician based on the number, length, depth, and texture. The score was scored independently using the double-blind method, and the statistical average was summarized. Each link was strictly controlled to accurately quantify the anti-wrinkle performance of the skin care composition from multiple dimensions, providing a solid basis for evaluation. The specific test results are shown in the table below: It can be seen from the anti-wrinkle effect test table that the anti-wrinkle effect of Example 1 is the most outstanding, with its wrinkle depth reduced by 0.08mm, skin elasticity increased by 28%, and crow's feet improvement score of 5 points, indicating that the combination is excellent in reducing wrinkle depth, enhancing skin elasticity and improving crow's feet, can effectively resist signs of skin aging, restore skin firmness and smoothness, and is the best choice among all the embodiments. Examples 3 and 5 also show good anti-wrinkle performance, with wrinkle depth reduced by 0.06-0.07mm, skin elasticity increased by 20%-25%, and crow's feet improvement score of 4 points. These embodiments provide nourishment and repair for the skin through the synergistic effect of various ingredients, enhance the activity of collagen and elastic fibers, enhance skin firmness and elasticity, reduce wrinkles, and improve the overall texture and appearance of the skin. They are of great application value in the field of anti-aging beauty and skin care, and provide strong support for product optimization and upgrading and the formulation of personalized skin care plans.
[0038] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.
Claims
1. An anti-aging beauty skin care composition, characterized in that: The composition comprises, by weight, 1 to 10 parts of Centella asiatica extract, 0.5 to 5 parts of sodium hyaluronate, 0.5 to 5 parts of grape seed extract, 0.1 to 2 parts of vitamin C, 0.5 to 3 parts of ceramide, 1 to 8 parts of ginseng root extract and 1 to 6 parts of green tea extract.
2. The anti-aging beauty skin care composition according to claim 1, characterized in that: The anti-aging beauty skin care composition comprises, by weight: 2 to 8 parts of Centella asiatica extract, 1 to 4 parts of sodium hyaluronate, 1 to 4 parts of grape seed extract, 0.5 to 1.5 parts of vitamin C, 1 to 2.5 parts of ceramide, 2 to 6 parts of ginseng root extract, and 2 to 5 parts of green tea extract.
3. The anti-aging beauty skin care composition according to claim 1, characterized in that: The anti-aging beauty skin care composition comprises, by weight: 5 parts of Centella asiatica extract, 2.5 parts of sodium hyaluronate, 2 parts of grape seed extract, 1 part of vitamin C, 1.5 parts of ceramide, 4 parts of ginseng root extract, and 3 parts of green tea extract.
4. A method for preparing the anti-aging beauty skin care composition according to any one of claims 1 to 3, characterized in that: The specific steps are as follows: Step 1: Wash and dry Centella asiatica, extract with 70% to 80% ethanol at a solid-liquid ratio of 1:8 to 1:12, reflux at 50 to 60°C for 2 to 3 times, each time for 1.5 to 2 hours, filter and concentrate to obtain the extract for later use; Step 2: Select medical grade or cosmetic grade sodium hyaluronate powder, pass it through an 80-100 mesh sieve to remove possible impurities such as lumps, and place it in a dry, cool, ventilated place for later use; Step 3: Purchase high-quality grape seeds, wash and crush them into 20-40 mesh size particles, use supercritical CO2 extraction technology, set the extraction pressure to 25-35MPa, the temperature to 40-50°C, and the extraction time to 1.5-2.5 hours, collect the extracted grape seed extract, place it in a sealed container, and store it at a low temperature of 0-5°C away from light for later use; Step 4: Select L-type vitamin C crystals with a purity of more than 99%. To prevent oxidation, seal and store them in a dry, dark environment below 25°C before use; Step 5: Choose cosmetic-grade ceramide raw materials, which are usually purchased in the form of liposomes to ensure better stability and skin permeability; Step 6: Wash and slice the ginseng roots, boil them in water for extraction (80-90°C, material-liquid ratio 1:10-1:15, 2-3 times), then precipitate with alcohol, filter and concentrate for later use; Step 7: Select high-quality green tea leaves, crush them to a fineness of 30-50 mesh, and extract them 2-3 times with 80-90°C hot water at a material-liquid ratio of 1:10-1:15, combine and filter, then spray-dry into powder for later use; Step 8: Premixing: Accurately weigh each ingredient according to the formula, place it in a clean, sterile stainless steel mixing tank with a stirring device, start low-speed stirring at 100-200 rpm for 5-10 minutes to preliminarily mix the ingredients evenly; Step 9: Heating and homogenizing: Turn on the heating device of the mixing tank and slowly raise the temperature to 60-70°C. At this temperature, switch to high-speed stirring at a speed of 800-1200 rpm. Simultaneously start the homogenizer at a homogenizing pressure of 20-30 MPa. Homogenize the mixture for 10-15 minutes to form a uniform colloidal mixture. Step 10: Cooling and filtration: After homogenization, turn off the heating device, cool the mixture in the mixing tank by circulating cooling water in the jacket to 30-40°C, and filter the mixture using a sterilizing filter with a filtration accuracy of 0.22-0.45 μm to obtain a clear, sterile anti-aging beauty and skin care composition; Step 11: Packaging and storage: The filtered composition is filled into pre-sterilized skin care product packaging containers through automated filling equipment. After sealing, the containers are stored in a cool, dry and ventilated warehouse environment.
5. The method for preparing an anti-aging beauty skin care composition according to claim 4, characterized in that: In the premixing step, each component is pretreated before being added to the mixing tank, wherein the Centella asiatica extract is extracted and concentrated, the sodium hyaluronate is sieved, the grape seed extract is subjected to supercritical CO2 extraction and preservation, the vitamin C is sealed and preserved, the ceramide is pretreated by liposome encapsulation, the ginseng root extract is boiled, precipitated and concentrated, and the green tea extract is crushed, leached and spray-dried.
6. The method for preparing the anti-aging beauty skin care composition according to claim 4, characterized in that: In the heating and homogenizing step, the heating rate is controlled at 1-2° C. per minute.
7. The method for preparing an anti-aging beauty skin care composition according to claim 4, characterized in that: In the packaging and storage step, the skin care product packaging container is sterilized by ultraviolet irradiation or high-temperature steam sterilization, the temperature of the warehouse environment is controlled at 15-25° C., and the relative humidity is controlled at 40%-60%.