Nanocellulose for use as an SPF booster, an SPF booster composition comprising said nanocellulose, and a sunscreen composition comprising said nanocellulose or SPF booster composition

Abstract

The present invention discloses a nanocellulose for use as an SPE booster in a sunscreen composition characterized in that the nanocellulose has an average width ranging from 10-50 nm, an average length ranging from 700-1,200 nm, and a crystallinity index ranging from 60-75%. In addition, the present invention also discloses an SPF booster composition comprising said nanocellulose, and a sunscreen composition comprising said nanocellulose and / or SPF booster composition.

Description

[0001] NANOCELLULOSE FOR USE AS AN SPF BOOSTER, AN SPF BOOSTER COMPOSITION COMPRISING SAID NANOCELLULOSE, AND

[0002] A SUNSCREEN COMPOSITION COMPRISING SAID NANOCELLULOSE

[0003] OR SPF BOOSTER COMPOSITION

[0004] TECHNICAL FIELD

[0005] Chemical technology related to a nanocellulose for use as an SPF booster, an SPF booster composition comprising said nanocellulose, and a sunscreen composition comprising said nanocellulose or SPF booster composition

[0006] BACKGROUND OF THE INVENTION

[0007] Sunscreen products are essential personal care products that protect the skin from sunlight and prevent damage caused by ultraviolet or UV rays from the sun, which is one of the main causes of skin cancer and premature wrinkles. Generally, sunscreen products can be classified into two main types: chemical sunscreen and physical sunscreen. In terms of usage, physical sunscreen offers several advantages over chemical sunscreen. For example, it is gentler on the skin, less likely to cause allergies, and provides immediate protection from sunlight upon application, unlike chemical sunscreen which requires at least 15-20 minutes after application for the active ingredients to become effective.

[0008] Although physical sunscreen products offer the advantages mentioned above, in order to achieve sufficient effectiveness in protecting the skin from sunlight and UV rays, it is necessary to use a high amount of mineral-based sunscreen agents, such as titanium dioxide or zinc oxide, to obtain the required Sunburn Protection Factor (SPF) and UVA Protection Factor (UVAPF). Using a high amount of mineral-based sunscreen may cause a white cast on the skin after application and make the sunscreen product highly viscous, making it difficult to spread evenly on the skin. This can negatively affect the effectiveness of skin protection against sunlight and UV rays and result in user dissatisfaction.

[0009] Due to the problems mentioned above, there is an effort to invent and develop additives, including auxiliary compositions, that can enhance the effectiveness of sunlight and UV protection in sunscreen products, as well as improving the texture of physical sunscreen products. Examples of the published patent documents are as follows.

[0010] WO 2008126971 Al discloses polymer nanoparticles and UV-blocking agents comprising said polymer particles. The polymer nanoparticles are prepared by mixing the UV-blocking agents, such as zinc oxide (ZnO), titanium dioxide (TiO2), benzophenone-4, octyl salicylate, with a polymer solution, such as chitosan, gelatin, or collagen. Then, a crosslinker, such as sodium triphosphate, sodium citrate, or sodium oxalate, is added to obtain the polymer nanoparticles which offer protection against UV rays and are non-toxic to the human body.

[0011] WO 2018100062 Al discloses the use of nanocrystalline cellulose, particularly carboxylated nanocrystalline cellulose, to address the issue of white cast in physical sunscreen products and to offer better flowability to sunscreen products even after long-term storage. The nanocrystalline cellulose has a preferred particle size ranging from 2-10 micrometers (pm).

[0012] SUMMARY OF THE INVENTION

[0013] It is an object of the present invention to develop additives and auxiliary compositions suitable for enhancing the effectiveness of sunlight and UV protection of sunscreen products, particularly physical sunscreen products.

[0014] In one aspect, the present invention relates to a nanocellulose for use as an SPF booster in a sunscreen composition. The particularly preferred nanocellulose for use in achieving the object of the present invention is nanocellulose with an average width ranging from 20-50 nm, an average length ranging from 700-1,200 nm, and a crystallinity index ranging from 60-75%.

[0015] In another aspect, the present invention further relates to an SPF booster composition comprising nanocellulose having the characteristics according to the present invention as mentioned above and metal-oxide, and to a sunscreen composition comprising said nanocellulose or SPF booster composition.

[0016] The nanocellulose and SPF booster composition according to the present invention can significantly improve the effectiveness of sunlight and UV protection of the sunscreen composition, as seen from the significant increase in SPF and UVAPF in the sunscreen composition containing the nanocellulose and SPF booster composition according to the present invention.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Fig. 1 is a graph showing the light absorbance in the UV range of the nanocellulose sample according to the present invention (Sample 1), the SPF booster composition sample comprising the nanocellulose according to the present invention and metal-oxide (Sample 2), commercially available nanocellulose sample (Comparative sample 1), and a mineral-based sunscreen agent sample which is zinc oxide (Comparative sample 2).

[0019] Fig. 2 is a graph showing the light absorbance in the UV range of the sunscreen lotion composition sample comprising the nanocellulose according to the present invention (Sample 1), the SPF booster composition comprising the nanocellulose according to the present invention and metal-oxide (Sample 2), a base lotion (Comparative sample 1), and a base lotion comprising a mineral-based sunscreen agent which is zinc oxide (Comparative sample 2).

[0020] DETAILED DESCRIPTION

[0021] Any aspects shown herein shall encompass the application to other aspects of the present invention as well, unless specified otherwise.

[0022] Any tools, equipment, methods, materials, or chemicals mentioned herein, unless specified otherwise, shall mean the tools, equipment, methods, materials, or chemicals generally used or practiced by a person skilled in the art, unless expressly specified to be tools, equipment, methods, materials, or chemicals specific to the present invention.

[0023] The terms “comprise(s),” “consist(s) of,” “has / have,” and “include(s)” are open-ended verbs. For example, any methods which “consist of,” “comprise,” “have,” or “include” one or more components or one or more steps are not limited only to the one or more components or one or more steps but also cover the components or steps that are not mentioned.

[0024] All components and / or methods disclosed and claimed in the present invention are intended to cover the aspects of the invention obtained from any actions, practices, modifications or changes of factors without conducting significantly different experiment from the present invention, and to obtain an object with properties, utilities and effects that are similar to the aspects of the present invention according to the opinions of a person of ordinary skill in the art, although not specifically stated in the claims. Therefore, substitutions or analogues of the aspects of the present invention, including any slight modification or change apparent to a person of ordinary skill in the art, should also be considered to be within the spirit, scope and concept of the present invention.

[0025] Technical and scientific terms used herein have the definitions as understood by a person of ordinary skill in the art, unless defined otherwise.

[0026] The object of the present invention can be achieved with the nanocellulose and SPF booster composition having the following characteristics. 1. Nanocellulose for use as an SPF booster

[0027] According to the present invention, the nanocellulose for use as the SPF booster in the sunscreen composition has an average width ranging from 10-50 nm, an average length ranging from 700-1,200 nm, and a crystallinity index ranging from 60-75%.

[0028] The nanocellulose preferably has an average width ranging from 20-50 nm, more preferably 20-30 nm, an average length ranging from 200-500 nm, and a crystallinity index ranging from 70-75%.

[0029] In an embodiment, the nanocellulose according to the present invention has an average particle size ranging from 200-400 nm, preferably from 300-350 nm.

[0030] In a specific embodiment of the invention, the nanocellulose is a native nanocellulose or unmodified nanocellulose prepared by a mechanical method. As an example, the nanocellulose according to the present invention is chemically unmodified nanocellulose, non-oxidized nanocellulose, and / or non-fimctionalized nanocellulose.

[0031] The increased effectiveness in sunlight and UV protection of the nanocellulose according to the present invention is achieved through the nanocellulose’s network structure, which can retain sunscreen particles, such as metal-oxide, within its structure and / or on its surface. This prevents them from aggregating or agglomerating together and allowing them to disperse uniformly when applying and spreading the product on the skin.

[0032] 2. SPF booster composition

[0033] According to the present invention, the SPF booster composition comprises the nanocellulose having the aforementioned characteristics and a metal-oxide, which can be present within a network structure and / or on a surface of the nanocellulose.

[0034] Preferably, the metal-oxide according to the present invention has an average particle size ranging from 40-800 nm.

[0035] In a preferred embodiment, the SPF booster composition has a weight ratio of the metal-oxide to nanocellulose in a range of 5:95 to 15:85, more preferably in a range of 8:92 to 12:88.

[0036] As an example, the metal-oxide may be selected from titanium dioxide, zinc oxide, or a combination thereof

[0037] 3. Sunscreen composition

[0038] The sunscreen composition according to the present invention comprises the nanocellulose or SPF booster composition having the aforementioned characteristics. In a preferred embodiment, the sunscreen composition comprises the nanocellulose in an amount ranging from 1-5 wt% of the sunscreen composition, preferably from 1-3 wt% of the sunscreen composition.

[0039] In an aspect, the sunscreen composition comprises the SPF booster composition in an amount ranging from 1-5 wt% of the sunscreen composition, preferably from 1-3 wt% of the sunscreen composition.

[0040] The sunscreen composition according to the present invention may be prepared in various forms as needed for ease of use, such as in the form of cream, gel, or lotion

[0041] Example

[0042] The present invention will now be described in more detail with reference to the examples of the invention and the experimental results to be mentioned hereinafter with reference to the accompanying drawings. The examples of the invention shown herein are not intended to limit the scope of the invention in any way.

[0043] 1. Nanocellulose for use as an SPF booster

[0044] The nanocellulose sample according to the present invention was prepared by subjecting dissolving pulp derived from eucalyptus to an acid hydrolysis reaction. Then, the cellulose fiber suspension was neutralized by washing it with water. The size of the resulting cellulose fiber suspension was reduced using a mechanical method to obtain nanocellulose with an average particle size ranging from 200-400 nm, an average width ranging from 10-50 nm, and an average length ranging from 700-1,200 nm. The nanocellulose obtained is in the form of colloidal gel with a consistency of about 2-3%.

[0045] The nanocellulose sample obtained was then analyzed using the Dynamic Light Scattering (DLS) technique to compare it with the commercially available nanocellulose sample, as shown in Table 1.

[0046] Table 1 From the analysis results using the DLS technique in Table 1, it can be seen that the nanocellulose sample according to the present invention (Sample NC-A) has a smaller average particle size compared to the commercially available nanocellulose sample (Sample NC-B) and a significantly higher crystallinity index than the commercially available nanocellulose.

[0047] The nanocellulose sample according to the present invention and the commercially available nanocellulose sample were further tested by measuring their light absorbance in the UVA and UVB ranges at wavelengths of 280-400 nm using a Jasco V 650 UV spectrophotometer using a 10 mm cell length, photometer mode: absorbance, and light source D2W. Distilled water was used as a blank. The test samples were prepared by diluting the samples containing the type and amount of each component, as shown in Table 2, with distilled water in a volume ratio of 1 :49. The experimental results are as shown in Fig.1.

[0048] Table 2

[0049] From the experimental results in Fig. 1, it can be seen that the nanocellulose sample according to the present invention (Sample NC-A) clearly exhibits higher light absorbance in the UVA and UVB ranges than the commercially available nanocellulose sample (Sample NC-B).

[0050] 2. SPF booster composition

[0051] The SPF booster composition sample according to the present invention was prepared by mixing the nanocellulose sample according to the present invention (Sample NC-A) with a metal-oxide using a mechanical method at a weight ratio of nanocellulose to metal-oxide of 90: 10.

[0052] Then, the SPF booster composition sample prepared from the nanocellulose according to the present invention was measured for its light absorbance in the UVA and UVB ranges at wavelengths of 280-400 nm using a Jasco V 650 UV spectrophotometer using a 10 nm cell length, photometer mode: absorbance, and light source D2W to compare the absorption efficiency in the UVA and UVB ranges to that of the nanocellulose sample and the mineral-based sunscreen agent, such as zinc oxide (ZnO). Distilled water was used as a blank. The test samples were prepared by diluting the samples containing the amount and type of each component, as shown in Table 3, with distilled water in a volume ratio of 1 :49. The experimental results are as shown in Fig.1.

[0053] Table 3

[0054] It can be seen from Fig. 1 that the SPF booster composition sample comprising the nanocellulose and zinc oxide according to the present invention (Sample 2) exhibit increased light absorbance in the UVA and UVB ranges compared to the nanocellulose sample which does not contain zinc oxide (Sample 1). Moreover, the experimental results suggest that the SPF booster composition according to the present invention exhibits significantly higher light absorbance in the UVA and UVB ranges than the mineral-based sunscreen agent (Comparative sample 2).

[0055] 3. Sunscreen composition

[0056] Various forms of the sunscreen composition samples were prepared for testing the absorbance efficiency in the UVA and UVB ranges and the efficiency in increasing the SPF and UVAPF as follows.

[0057] 3.1 Sunscreen lotion formulation

[0058] The sunscreen composition samples according to the present invention (Samples 1 and 2 in Table 4) and the comparative samples (Comparative samples 1 and 2 in Table 4) were prepared in the form of lotion with the amount of each component shown in Table 4. The total amount of zinc oxide in each sample was controlled to be 5.5 wt%, based on the total weight of the sunscreen composition. Table 4

[0059] Notes:

[0060] * Base lotion is lotion which does not contain sunscreen agents.

[0061] ** The SPF booster composition according to the present invention contains zinc oxide in an amount of 0.5 wt%, based on the total weight of the sunscreen composition.

[0062] Then, the prepared sunscreen composition samples were measured for their light absorbance in the UVA and UVB ranges at wavelengths of 280-400 nm using a Jasco V 650 UV spectrophotometer using a 10 nm cell length, photometer mode: absorbance, and light source D2W. Distilled water was used as a blank. The test samples were prepared by diluting the samples containing the amount and type of each component, as shown in Table 4, with distilled water in a volume ratio of 1 :49. The experimental results are as shown in Fig.2.

[0063] From the experimental results in Fig. 2, it can be seen that the sunscreen lotion formulations containing the nanocellulose or SPF booster composition according to the present invention (Samples 1 and 2) exhibit increased light absorbance in the UVA and UVB ranges compared to Comparative sample 1, which is a base lotion without any added sunscreen or SPF booster, and Comparative sample 2, which is a base lotion with only one mineral-based sunscreen agent added.

[0064] 3.2 Sunscreen formulation

[0065] The sunscreen composition samples according to the present invention (Samples 3, 4, and 5 in Table 5) and the comparative samples (Comparative samples 3 and 4 in Table 5) were prepared in the form of cream. The amount of each component is shown in Table 5. The types and amounts of the nanocellulose, mineral-based sunscreen, and metal-oxide contained in the composition are shown in Table 6. Table 5

[0066] Notes:

[0067] * Standard sunscreen is sunscreen which does not contain nanocellulose.

[0068] The standard sunscreen according to the present invention contains mineral-based sunscreens, which are titanium dioxide (TiO2) in an amount of 4 wt% and zinc oxide (ZnO) in an amount of 5.76 wt%, based on the total weight of the sunscreen composition.

[0069] ** The SPF booster composition according to the present invention contains zinc oxide in an amount of 0.25 wt%, based on the total weight of the sunscreen composition.

[0070] Table 6 The prepared sunscreen composition samples were tested for the UV protection efficiency and the % improvement of each sample was compared, as shown in Table 7.

[0071] Table 7

[0072] When comparing the effectiveness of enhancing sunlight protection, including UV protection, in physical sunscreen, Table 7 shows that the nanocellulose according to the present invention (Samples 3 and 4) can increase the SPF by up to 120.7% and UVAPF by up to 41.1% compared to the standard sunscreen (Comparative sample 3). It is also more effective than the use of commercially available nanocellulose (Comparative sample 4), in which the SPF was increased by only 76.6% and UVAPF by only 29.3% compared to the standard sunscreen (Comparative sample 3).

[0073] Furthermore, the SPF booster composition according to the present invention (Sample 5) also demonstrates excellent effectiveness in enhancing sunlight protection, including UV protection, in physical sunscreen. That is, it can increase the SPF by up to 132.5% and the UVAPF by up to 48.4% compared to the standard sunscreen (Comparative sample 3). It is also more effective than the use of commercially available nanocellulose (Comparative sample 4), in which the SPF was increased by only 76.6% and UVAPF by only 29.3% compared to the standard sunscreen (Comparative sample 3).

[0074] Additionally, the effectiveness of enhancing sunlight protection, including UV protection, in physical sunscreen was compared between the nanocellulose (NC-A) and the SPF booster composition according to the present invention (Samples 3 and 5 in Table 7, respectively) and the disclosed information of the prior arts related to commonly used SPF boosters, i.e., natural waxes, such as a mixture of Copernicia Cerifera (Carnauba) wax and Oryza Sativa Bran wax contained in Comparative sample 5, and polymers, such as acrylate / methacryloyloxy ethyl phosphate copolymer contained in Comparative sample 6. The comparison results are shown in Table 8. Table 8

[0075] From Table 8, it was found that the use of the nanocellulose according to the present invention (Sample 3) is effective in increasing the SPF by up to 121%, from 17.7 to 39.2. It can also increase the UVAPF by up to 43%, from 6.0 to 8.6, compared to the standard sunscreen. It also demonstrates significantly higher effectiveness than the SPF boosters which are waxes (Comparative sample 3) and polymers (Comparative sample 5).

[0076] Additionally, it was found that the SPF booster composition, which is nanocellulose with zinc oxide according to the present invention (Sample 5), effectively increases the SPF by up to 133%, from 17.7 to 41.3. It can also increase the UVAPF by up to 50%, from 6.0 to 9.0, compared to the standard sunscreen. It also demonstrates significantly higher effectiveness than the SPF boosters which are waxes (Comparative sample 5) and polymers (Comparative sample 6).

[0077] From the above experimental results, it can be seen that the nanocellulose and SPF booster composition according to the present invention are suitable for use as additives or auxiliary compositions to enhance sunlight and UV protection in sunscreen compositions, especially in physical sunscreen compositions.

[0078] BEST MODE OF THE INVENTION

[0079] Best mode of the invention is as described in the detailed description of the invention.

Claims

WHAT IS CLAIMED IS:

1. A nanocellulose for use as an SPF booster in a sunscreen composition characterized in that the nanocellulose has an average width ranging from 10- 50 nm, an average length ranging from 700-1,200 nm, and a crystallinity index ranging from 60-75%.

2. The nanocellulose according to claim 1, having the crystallinity index ranging from 70-75%.

3. An SPF booster composition comprising the nanocellulose according to claim1 or 2 and a metal-oxide.

4. The SPF booster composition according to claim 3, wherein the metal-oxide is present within a network structure of the nanocellulose and / or on a surface of the nanocellulose.

5. The SPF booster composition according to claim 3 or 4, wherein the metal-oxide has an average particle size ranging from 40-800 nm.

6. The SPF booster composition according to any one of claims 3-5, wherein a weight ratio of the metal-oxide to nanocellulose ranges from 5:95 to 15:85.

7. The SPF booster composition according to any one of claims 3-6, wherein the metal-oxide is selected from titanium dioxide, zinc oxide, or a combination thereof.

8. A sunscreen composition comprising the nanocellulose according to claim 1 or2 or the SPF booster composition according to any one of claims 3-7.

9. The sunscreen composition according to claim 8, wherein the nanocellulose is present in an amount ranging from 1-5 wt% of the sunscreen composition.

10. The sunscreen composition according to claim 8, wherein the SPF booster composition is present in an amount ranging from 1-5 wt% of the sunscreen composition.

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