Coating formulation

Abstract

A coating formulation comprising alginate, hydrophilic polymer, preservative and solvent, wherein the alginate is present at an amount of from 0.1% to 2% by weight of the coating formulation, wherein the hydrophilic polymer is present at an amount of from 0.05% to 0.1% by weight of the coating formulation, wherein the preservative is present at an amount of from 0.05% to 0.1% by weight of the coating formulation and wherein the solvent is present at an amount of at least 97% by weight of the coating formulation. A glove coated with at least one layer of coating prepared from the above- mentioned coating formulation.

Description

[0001] COATING FORMULATION

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a coating formulation and method of manufacturing thereof, in particular a coating formulation for coating a polymeric article such as, but not limited to, a glove. A glove coated with the coating formulation of the present invention can exhibit desired sweat absorption capacity that helps to improve skin hydration, as well as reducing the transepidermal water loss of a user’s skin.

[0004] BACKGROUND OF THE INVENTION

[0005] Gloves manufactured from polymeric materials such as natural rubber and synthetic latexes are widely used in many industries such as food and beverage, medical institution and scientific laboratory. Prolonged glove donning can cause hand dermatitis such as hydration dermatitis and contact dermatitis.

[0006] Contact dermatitis is the skin irritation that could be caused by direct contact between skin and glove film. Hydration dermatitis could be caused by the constant diffusion of sweat from inner dermis layer to stratum corneum which is the outermost layer of the skin, causing accumulation of sweat inside the glove. After prolonged glove donning, excessive sweat could cause the thickening of stratum corneum due to extensive swelling of corneocytes. This condition is known as hydration injury.

[0007] On the other hand, accumulation of sweat inside the glove might cause the surfactant to be leached out from the glove, causing contact dermatitis on the user’s skin. Both hydration and contact dermatitis could lead to damaged skin’s moisture barrier, increased transepidermal water loss (TEWL), skin inflammation and penetration of foreign substances into the skin.

[0008] Thus, there is a need for the provision of articles formed from polymeric materials, in particular gloves, which display beneficial effects towards the condition of a user’s skin.

[0009] SUMMARY OF THE INVENTION

[0010] The present invention provides a coating formulation comprising alginate, a hydrophilic polymer, a preservative and a solvent, wherein the alginate is present at an amount of from 0.1 % to 2% by weight of the coating formulation, wherein the hydrophilic polymer is present at an amount of from 0.05% to 0.1 % by weight of the coating formulation, wherein the preservative is present at an amount of from 0.05% to 0.1 % by weight of the coating formulation, and wherein the solvent is present at an amount of at least 97 % by weight of the coating formulation.

[0011] The coating formulation of the present invention may be used to coat a surface of a polymeric material (e.g. an elastomeric material) such as a surface of a glove formed from a polymeric material (e.g. a nitrile glove, a polyisoprene glove, a latex glove, or a polyvinyl glove). In particular, the coating formulations provide a coated glove that exhibits desired sweat absorption capacity which helps to improve the skin hydration as well as reduce the TEWL of the user’s skin.

[0012] Thus, the present invention also provides a glove coated with a coating formulation of the present invention.

[0013] The present invention also provides a method of preparing a coating formulation of the present invention.

[0014] Additional aspects, features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments of the invention. As can be appreciated from the foregoing and following description, each and every feature described herein, and each and every combination of two or more such features, is included within the scope of the present disclosure provided that the features included in such a combination are not mutually inconsistent. In addition, any feature or combination of features may be specifically excluded from any embodiment.

[0015] BRIEF DESCRIPTION OF FIGURES

[0016] Figure 1 shows the sweat absorption capacity of gloves coated with coating formulations containing alginate compared to a glove with no coating.

[0017] Figure 2 shows the effect of alginate on the sweat absorption capacity properties of the coating formulations of the present invention. Figure 3 shows the sweat absorption capacity of gloves coated with coating formulations of the present invention compared to gloves coated with coating formulations of the prior art.

[0018] DETAILED DESCRIPTION OF THE INVENTION

[0019] A detailed description of preferred embodiments of the present invention is disclosed herein. It should be understood, however, the embodiments are merely exemplary of the present invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limiting, but merely as the basis for the claims and for teaching one skilled in the art of the invention. The numerical data or ranges used in the specification are not to be construed as limiting.

[0020] The present invention relates to a coating formulation and method of manufacturing thereof. The coating formulation of the present invention is particularly useful as a coating for polymeric articles such as, but not limited to, gloves formed from a polymeric material. A glove coated with the coating formulation of the present invention can exhibit desired sweat absorption capacity that helps to improve the skin hydration, as well as reduce the transepidermal water loss (TEWL) of the user’s skin.

[0021] For the purpose of the present invention, the term “inner surface” refers to the surface of a glove which is in contact with the user’s skin when the glove is worn. For the purpose of the present invention, the term “sweat absorption capacity” refers to the total amount of sweat being absorbed. For the purpose of the present invention, the term “skin hydration” refers to the amount of water content in the stratum corneum of the skin. For the purpose of the present invention, the term “transepidermal water loss”, or “TEWL”, refers to the amount of water that passively evaporates through skin to the external environment due to water vapor pressure gradient on both sides of the skin barrier.

[0022] A first aspect of the present invention provides a coating formulation that is subsequently used to form a layer of coating on the inner surface of a polymeric material article such as, but not limited to, a glove formed from a polymeric material.

[0023] The coating formulation of the present invention may have a total solid content ranging from about 0.2% to about 2.2% by weight of the coating formulation. The coating formulation of the present invention may also have a pH value ranging from about 3.5 to about 8. For example, the coating formulation of the present invention may have a total solid content ranging from about 0.2% to about 1.2% by weight of the coating formulation and a pH value ranging from about 3.5 to about 8.

[0024] The coating formulation comprises alginate, a hydrophilic polymer, a preservative and a solvent (see, for example, the formulations described in Table 1).

[0025] In particular, the coating formulation of the present invention comprises alginate, a hydrophilic polymer, a preservative and a solvent, wherein the alginate is present in the coating formulation at an amount of from about 0.1% to about 2% by weight of the coating formulation, wherein the hydrophilic polymer is present in the coating formulation at an amount of from about 0.05% to about 0.1% by weight of the coating formulation, wherein the preservative is present in the coating formulation at an amount of from about 0.05% to about 0.1 % by weight of the coating formulation, and wherein the solvent is present in the coating formulation at an amount of at least about 97% by weight of the coating formulation.

[0026] The coating formulation of the present invention is suitable for coating a glove. In particular for coating the inner surface of a glove, such as a nitrile glove, a polyisoprene glove, a latex glove, or a polyvinyl glove.

[0027] In embodiments herein, the word “comprising” may be interpreted as requiring the features mentioned, but not limiting the presence of other features. Alternatively, the word “comprising” may also relate to the situation where only the components / features listed are intended to be present (e.g. the word “comprising” may be replaced by the phrases “consists of” or “consists essentially of”). It is explicitly contemplated that both the broader and narrower interpretations can be applied to all aspects and embodiments of the present invention. In other words, the word “comprising” and synonyms thereof may be replaced by the phrase “consisting of’ or the phrase “consists essentially of’ or synonyms thereof and vice versa.

[0028] Thus, in certain embodiments, the coating formulation of the present invention may consist essentially of, or consist of, alginate, the hydrophilic polymer, the preservative and the solvent. For example, the coating formulation of the present invention may consist essentially of, or consist of, alginate, the hydrophilic polymer, the preservative and the solvent, wherein the alginate is present in the coating formulation at an amount of from about 0.1 % to about 2% by weight of the coating formulation, wherein the hydrophilic polymer is present in the coating formulation at an amount of from about 0.05% to about 0.1 % by weight of the coating formulation, wherein the preservative is present in the coating formulation at an amount of from about 0.05% to about 0.1 % by weight of the coating formulation, and wherein the solvent makes up the remaining portion of the coating formulation (e.g. the solvent may be present in the coating formulation at an amount of from 97.8% to 99.8% by weight of the coating formulation).

[0029] The term “about” as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, within 1 %, within 0.5%, within 0.1 %, within 0.05%, within 0.01%, within 0.005%, or within 0.001 % of a stated value or of a stated limit of a range, and includes the exact stated value or range.

[0030] The alginate present in the coating formulation of the invention may be selected from the group consisting of sodium alginate, potassium alginate, calcium alginate, ammonium alginate, and a mixture of two or more thereof. Preferably, the alginate is sodium alginate. In certain embodiments, the alginate is present in the coating formulation in an amount ranging from about 0.1 % and about 2%, for example, from about 0.1% and about 1.5%, or about 0.1 % and about 1%, preferably from about 0.1 % to about 0.5% (e.g. about 0.25% to about 0.45%, or about 0.3% to about 0.4%), more preferably about 0.34% by weight of the coating formulation.

[0031] The alginate is typically used in a powder form. For example the alginate may be used as a powder with a particle size of about 100 pm to about 300 pm, for example about 150 pm to about 200 pm (e.g. about 177 pm). The alginate may also have a viscosity of from about 100 cPs to about 1000 cPs (from about 0.1 Pa-s to about 1 Pa-s) at 20 °C when in the form of an aqueous solution consisting of water and 1 wt% alginate. For example, the alginate may have a viscosity of from about 100 cPs to about 1000 cPs (from about 0.1 Pa-s to about 1 Pa-s) when in the form of an aqueous solution consisting of water and 1 wt% alginate, and measured using a Brookfield viscometer at 20 °C. In certain preferred embodiments, the alginate is present in the coating formulation at an amount of less than or equal to about 1 % by weight of the coating formulation. Without wishing to be bound by theory, the present inventors believe that when the alginate is present in an amount of less than or equal to about 1% by weight of the coating formulation, an effective coating can be easily applied to the inner surface of a glove; for example, it may facilitate the application of the coating formulation to the inner surface of a glove as an even and homogenous coating layer, and allow for consistent, fast and high volume manufacture of a coated glove.

[0032] The hydrophilic polymer present in the coating formulation of the invention may be selected from the group consisting of water-based silicone polymer, acrylic-based copolymer, and a mixture of two or more thereof. Preferably, the hydrophilic polymer is an acrylic-based copolymer. In embodiments, the hydrophilic polymer is present in the coating formulation of the invention at an amount of from about 0.05% to about 0.1%. For example, the hydrophilic polymer may be present in the coating formulation of the invention at an amount of from about 0.06% to about 0.1%, or about 0.07% to about 0.09%. Preferably, the hydrophilic polymer is present in the coating formulation of the invention at an amount of about 0.08% by weight of the coating formulation. In certain embodiments, the hydrophilic polymer is an acrylic-based copolymer. For example, the hydrophilic polymer may be an acrylic-based copolymer formed from an acrylate monomer and / or a monomer that is an ester of acrylate (e.g. methyl acrylate or ethyl acrylate monomers). In certain embodiments, the hydrophilic polymer has a viscosity of less than about 50 mPa-s when in the form of an aqueous solution consisting of water and 19-21 wt% hydrophilic polymer and measured at 25 °C using a Brookfield viscometer.

[0033] The preservative present in the coating formulation of the invention may be selected from the group consisting of sodium benzoate, benzoic acid, calcium sorbate, erythorbic acid, potassium nitrate, and a mixture of two or more thereof. Preferably, the preservative present in the coating formulation of the invention is sodium benzoate. In embodiments, the preservative present in the coating formulation of the invention in an amount of from about 0.05% to about 0.1%. For example, the preservative may be present in the coating formulation of the invention at an amount of from about 0.06% to about 0.1%, or about 0.07% to about 0.09%. Preferably, the preservative is present in the coating formulation of the invention at an amount of about 0.08% by weight of the coating formulation.

[0034] The solvent is typically water. For example, the solvent may be selected from the group consisting of soft water, distilled water, deionized water, tap water, ultrapure water and a mixture of two or more thereof. Preferably, the solvent is soft water. In embodiments, the solvent is present in the coating formulation of the invention at least about 97% by weight of the coating formulation, for example, at least about 97.5%, at least about 97.8%, or at least about 98%. Typically, the solvent is present at an amount of at least about 97.8%, for example from about 97.8% to about 99.8% by weight of the coating formulation. For example, the solvent may be present in the coating formulation at an amount of from about 97.8% to about 99.8%, preferably from about 99.46% to about 99.8%, more preferably about 99.5% by weight of the coating formulation.

[0035] As used herein, the term “soft water” refers to water that contains less than 17 ppm of ions such as but not limited to calcium and magnesium. For the purpose of the present invention, the term “ultrapure water” is referring to water that contains only H2O as well as balanced number of H+and OH' ions, has a resistivity of 18.2 MQ.cm, total organic carbon of less than 10 ppb, bacterial count of less than 10 CFU / ml and must not contain any detectable endotoxins.

[0036] Table 1 shows the chemical components of exemplary coating formulations of the present invention.

[0037] Table 1: Chemical components and compositions of the coating formulation of the present invention A second aspect of the present invention provides a method of preparing the coating formulation of the present invention. The coating formulation of the present invention is prepared by adding alginate, hydrophilic polymer and preservative (composition as per T able 1 ) one after another with no particular order into the solvent (composition as per Table 1) while stirring at a speed of from about 500 rpm to about 2000 rpm for about 15 minutes to about 60 minutes, preferably about 30 minutes at a temperature ranging of from about 25 °C to about 40 °C. The present inventors have found that stirring the mixture of alginate, hydrophilic polymer and preservative at speed of up to 2000 rpm provides homogenous formulation that can be evenly coated on to a surface a glove.

[0038] For the purpose of the present invention, the phrase “one after another with no particular order” signifies that any one of the chemicals may be added first and followed by the other since order of mixing is not crucial.

[0039] A third aspect of the present invention provides a glove that is coated with a coating formulation of the present invention. For example, the glove may be coated with at least one layer of the coating formulation of the present invention. In certain embodiments, the coating formulation is according to the formulation described in Table 1.

[0040] The glove of the present invention may be formed from a polymeric material, for example, an elastomeric material. For example, the glove may be a nitrile glove, a polyisoprene glove, a latex glove, or a polyvinyl glove. In certain embodiments, the glove is a latex glove. In certain other embodiments, the glove is a nitrile glove.

[0041] The glove may be prepared by adopting any commonly known method in the glove manufacturing industry. For example, the glove may be prepare using a method comprising the steps of: i. cleaning a former to produce a cleaned former, wherein the first step is treatment using acidic solutions such as but not limited to nitric acid, the second step is treatment using alkaline solutions such as but not limited to aqueous sodium hydroxide solution, the third step is rinsing with hot water and the fourth step is drying to ensure the former surface is cleaned; ii. dipping the cleaned former obtained in step (i) into a coagulant solution at a temperature ranging between 55 °C to 60 °C to coat a coagulant layer on the former, wherein the coagulant solution is such as but not limited to 10 wt% to 20 wt% of calcium nitrate; iii. drying the coagulant layer coated on the former obtained in step (ii) at a temperature ranging between 55 °C to 65 °C to obtain a dried coagulant layer; iv. dipping the dried coagulant layer coated on the former obtained in step (iii) into the latex dipping tank containing latex formulation at a temperature ranging between 40 °C to 60 °C to coat a latex layer on the former; v. drying the latex layer coated on the former obtained in step (iv) at a temperature ranging between 80 °C to 150 °C to obtain dried latex film; vi. pre-leaching the dried latex film coated on the former obtained in step (v) with hot water at a temperature ranging between 40 °C to 60 °C to leach out chemical residues to obtain pre-leached latex film; vii. vulcanizing the pre-leached latex film coated on the former obtained in step (vi) by heating at a temperature ranging between 80 °C to 150 °C to leach out chemical residues to obtain vulcanized glove; viii. chlorinating the vulcanized glove obtained in step (vii) to obtain a treated glove, wherein the chlorine is used in a strength of 800 ppm to 2000 ppm; ix. neutralizing the chlorinated glove obtained in step (viii) with alkaline treatment and water to leach out chemical residues to obtain neutralized glove; x. dipping the neutralized glove obtained in step (ix) into the dipping tank containing coating formulation of the present invention (composition as described in Table 1) at a temperature ranging between 40 °C to 60 °C for a time duration ranging between 5 seconds to 20 seconds, preferably 10 seconds to obtain coated glove; xi. drying the coated glove obtained in step (x) to produce glove of the present invention; and xii. stripping the glove of the present invention obtained in step (xi) from the former. The latex formulation that is mentioned in step iv can be of any conventional latex formulation, preferably comprises a base polymer, a surfactant, vulcanizing accelerator and crosslinking agent (composition as described in Table 2).

[0042] The base polymer is selected from the group consisting of acrylonitrile butadiene rubber latex, natural rubber latex, polychloroprene latex, polyisoprene latex and mixtures thereof. The base polymer is used in an amount of 100 phr (also referred to parts per hundred rubber), wherein the parts per hundred rubber is used as a basis for amounting other chemicals.

[0043] The surfactant is sodium dodecylbenzenesulfonate (SDBS). The surfactant is used in an amount ranging between 0 phr to 0.5 phr and preferably ranging between 0 phr to 0.4 phr.

[0044] The vulcanizing accelerator is carbamate-based accelerator. The vulcanizing agent is used in an amount ranging between 0.5 phr to 2.0 phr and preferably ranging between 0.5 phr to 1.0 phr.

[0045] The crosslinking agent is sulphur. The crosslinking agent is used in an amount ranging between 0.5 phr to 2.0 phr and preferably ranging between 0.5 phr to 1 .5 phr.

[0046] Table 2 shows chemical components and compositions of the latex formulation of the present invention.

[0047] Table 2: Chemical components and compositions of the latex formulation disclosed herein.

[0048] *parts per hundred rubber

[0049] The glove of the present invention may be single layered or multi-layered. The following example is constructed to illustrate the present invention in a non-limiting sense.

[0050] The glove of the present invention is prepared by using a latex formulation as summarized in Table 2 and coated with the coating formulation of the present invention as summarized in Table 1 adopting any commonly known method in the glove manufacturing industry.

[0051] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0052] For the avoidance of doubt, the term "wt%" as used herein refers to the percentage by weight of a particular substance with respect to the total weight of a given composition (i.e. a coating formulation). For example, a coating formulation of the present invention containing 0.1 wt% alginate is to be understood as containing 0.1 g of alginate in every 100 g of the coating formulation. For the avoidance of doubt, the phrase “% by weight of the coating formulation” as used herein should be interpreted as having the same meaning as the term “wt%”, unless stated otherwise.

[0053] The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. The use of the expression “at least” or “at least one” suggests the use of one or more elements, as the use may be in one of the embodiments to achieve one or more of the desired objects or results.

[0054] The contents of the articles, patents, and patent applications, and all other documents and electronically available information mentioned or cited herein, are hereby incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. The applicant reserves the right physically to incorporate into this application any and all materials and information from any such articles, patents, patent applications, or other physical and electronic documents.

[0055] Further aspects and embodiments of the invention will now be discussed by reference to the following non-limiting examples.

[0056] EXAMPLES

[0057] The control glove refers to glove having no coating layer. Coated gloves tested in this example were coated on the inner surface with a coating formulation containing water and alginate. The alginate was present in the coating formulation in an amount of 0.10% by weight of the coating formulation, 0.17% by weight of the coating formulation, 0.34% by weight of the coating formulation, 0.50% by weight of the coating formulation, or 1.00% by weight of the coating formulation. The remaining portion of the coating formulation was water. The alginate used in this experiment was sodium alginate, and the gloves were nitrile gloves.

[0058] The test was carried out by way of donning a control glove or a coated glove onto a former with the inner surface facing outwards. The weight of the former together with the glove was then measured (rm). The former with the glove was soaked in artificial sweat for 30 seconds. Subsequently, the former with the glove was taken out of the solution and the excess sweat allowed to drip off from the glove surface for 10 seconds. Lastly, the weight of the former with the glove was measured (m2).

[0059] The artificial sweat comprised sodium chloride in an amount of 1.08% by weight of the artificial sweat, lactic acid (88%) in an amount of 0.12% by weight of the artificial sweat and urea in an amount of 0.13% by weight of the artificial sweat. The remaining portion of the artificial sweat was solvent, wherein the solvent was deionised water. The pH of the artificial sweat was adjusted to pH 6.5 with sodium hydroxide. The formula for calculating the sweat absorption capacity of glove is as shown below:

[0060] Sweat absorption capacity=m2-mi (1) Figure 1 shows the sweat absorption capacity of control glove and the coated gloves. Based on the results obtained, it is noticeable that the gloves having a coating layer prepared from the coating formulation comprising alginate in an amount of 0.10% by weight of the coating formulation, 0.17% by weight of the coating formulation, 0.34% by weight of the coating formulation, 0.50% by weight of the coating formulation and 1.00% by weight of the coating formulation have better sweat absorption capacity as compared to the control glove. This indicates that coating formulations containing alginate improve the sweat absorption capacity of the gloves.

[0061] Example 2: In-vivo assessment of skin properties (i.e. skin hydration and transepidermal water loss) in non-clinical settings

[0062] For the purpose of the present invention, the term “non-clinical setting” is referring to space or platform where it does not involve the examination and treatment of people.

[0063] The control glove refers to glove having no coating layer. A coated glove (denoted as “Algi_0.34”) was tested. This coated glove had a coating layer prepared from the coating formulation described in Example 1 that contained alginate in an amount of 0.34% by weight of the coating formulation. The gloves used in this experiment were nitrile gloves.

[0064] 8 adults aged at least 18 years old and above were involved as subjects for in-vivo assessments. During a pre-irritation phase, the subjects were requested to wear the control glove on both left and right hands for 8 hours per day for 3 consecutive days for pre-irritation purpose. Subsequently, during an active phase, the subjects were requested to wear the control glove on their left hand and the Algi_0.34 glove on their right hand for 8 hours per day for 4 consecutive days.

[0065] The subjects were tested for transepidermal water loss (TEWL) using a transepidermal water loss analyzer. Further, the subjects were tested for skin hydration using a skin moisture analyzer. The measurements (i.e. TEWL and skin hydration) were taken after at least 20 minutes of acclimatization under standard climatic conditions (21±1 °C; 50±10% relative humidity).

[0066] The formula for calculating the percentage of difference in TEWL is as shown below: Percentage of difference in TEWL (%)= (TEWL4-TEWLi) / TEWLi x 100 (2) wherein TEWL4is the measurement of TEWL measured on the day 4 of the active phase and TEWL1is the measurement of TEWL measured on the day 1 of the active phase.

[0067] The formula for calculating the percentage of difference in skin hydration is as shown below:

[0068] Percentage of difference in skin hydration (%) - (SH4- SHi) / SHi x 100 (3) wherein SH4is the measurement of skin hydration measured on the day 4 of the active phase and SHi is the measurement of skin hydration measured on the day 1 of the active phase.

[0069] Table 3 shows the average percentage of difference in TEWL and skin hydration of the subjects (10 adults aged at least 18 years old) between day 1 and day 4 of the active phase.

[0070] Table 3: The average percentage of difference in TEWL and skin hydration of the subjects between day 1 and day 4 of the active phase.

[0071] Based on the results shown in Table 3, it is noticeable that the average percentage of difference in skin hydration of subjects wearing a coated glove (i.e. Algi_0.34) was higher as compared to subjects wearing a control glove. This indicates that a glove having a coating layer prepared from the coating formulation containing alginate in an amount of 0.34% by weight of the coating formulation improves the hydration of the user’s skin.

[0072] Further, based on the results shown in Table 3, it is noticeable that the average percentage of difference in TEWL of subjects wearing glove of the present invention (Algi_0.34) is lower as compared to subjects wearing control glove. This indicates that the coated glove reduces the transepidermal water loss of the user’s skin.

[0073] As a whole, these results show that a glove coated with a coating formulation containing alginate can help improve the skin hydration as well as reduces the transepidermal water loss of the user’s skin.

[0074] Example 3: Further sweat absorption capacity experiments

[0075] An exemplary coating formation of the present invention (Table 4, Formulation A) was compared to a comparative coating formulation that did not contain alginate (see T able 4, Formulation B). Table 4: Formulations tested. n / a = not applicable.

[0076] The sweat absorption capacity of these coating formulations was tested using the method described in Example 1 above.

[0077] Results: The sweat absorption capacity of nitrile gloves coated with a coating formation are shown in Figure 2 and Table 5. Table 5: Sweat absorption of a glove comprising a coating formulation compared to a glove with no coating.

[0078] *The results are the average (mean) of the difference between gloves coated with a test formulation and a glove with no coating, based on five replicates for each formulation.

[0079] By comparing the sweat absorption capacity of gloves coated with Formulation A with gloves without a coating or coated with Formulation B, it is evident that the alginate is the major component associated with the sweat absorption capacity of the formulation of the invention. In addition, the sweat absorption capacity of gloves coated with Formulation A showed a two-fold increase (almost 200% difference) in sweat absorption as compared to the uncoated gloves.

[0080] Example 4: Comparison of the sweat absorption capacity of the coating formulation of the invention with coating formulations of the prior art.

[0081] The sweat absorption capacity of exemplary coating formations of the present invention (see Table 6 below) was compared with two glove coating formulations know in the art, namely coating formulations disclosed in US 2015 / 0359945 (see Table 7 below).

[0082] US 2015 / 0359945 is concerned with antimicrobial coating formulations for gloves, such as latex gloves. The formulations of US 2015 / 0359945 contain an antimicrobial agent (chlorhexidine and gentian violet), partially hydrolyzed polyvinyl acetate copolymer (PHPA), water, and gelatin. The PHPA is said to reduce stickiness / tackiness of the coated glove and help delivery of the antimicrobial agent, and the gelatin is said to aid the application of the formulation to a polymer surface. Table 6: Tested formulations of the present invention.

[0083] Table 7: Prior art formulation.

[0084] Formulations P1 corresponds to the “Gendine D” formulation of US 2015 / 0359945, and Formulation P2 corresponds to the “Gendine A” formulation of US 2015 / 0359945, except for the 20% chlorhexidine gluconate (CHG) component being replace with water.

[0085] Results:

[0086] The sweat absorption capacities of nitrile gloves coated with a coating formation of the present invention or a prior art formulation are shown in Figure 3 and Table 8.

[0087] Table 8: Sweat absorption of a glove comprising a coating formulation of the present invention or the prior art compared to a glove with no coating.

[0088] *with respect to the glove with no coating.

[0089] The amount of alginate in Formulation C is equivalent to the amount of gelatin in Formulation P1, and the amount of alginate in Formulation D is equivalent to the amount of gelatin in Formulation P2. These results show that the formulations containing alginate display better sweat absorbing capacity compared to prior art formulations based on the proportion of alginate / gelatin present in the formulations.

[0090] Example 5: Comparison of the transepidermal water loss (TEWL) and skin hydration effects of the coating formulation of the invention with coating formulations of the prior art in non-clinical settings.

[0091] The method for determining the effects of coating formulations of the invention and prior art formulations on TEWL and skin hydration were determined using the method described in Example 2.

[0092] However, in the present example, no pre-irritation phase was used, and the TEWL and SH were determined at day 4 of the active phase and also at day 4 of a washout phase. The washout phase is the period following the 4 day active phase during which time the participants did not wear any gloves. Equation (2) was used to determine the percentage difference in TEWL on day 4 of the active phase, and Equation (4) was used to determine the percentage difference in TEWL on day 4 of the washout phase is as follows: :

[0093] Percentage of difference in TEWL (%) = (TEWL8-TEWLi) / TEWLi x 100 (4) wherein TEWLs is the measurement of TEWL measured on day 4 of washout phase (i.e. day 8 of the experiment), respectively. As for Example 2, TEWLi is the measurement of TEWL measured on day 1 of the active phase (i.e. a baseline measurement).

[0094] In the present example, Equation (3) was used to determine the skin hydration on day 4 of the active phase, and Equation (5) was used to determine the skin hydration on day 4 of the washout phase is as follows:

[0095] Percentage of difference in skin hydration (%) - (SHa - SHi) / SHi x 100 (5) wherein SHs is the measurement of skin hydration measured on day 4 of the washout phase (i.e. day 8 of the experiment), respectively. As for Example 2, SHi is the measurement of SH measured on day 1 of the active phase (i.e. a baseline measurement).

[0096] The measurement of TEWL and SH at day 4 of a washout phase is more representative of the longer terms effects of the coating formulation on skin condition, as it reflects the response of the skin barrier after donning gloves. The TEWL and SH of Formulation C was compared with prior art Formulation P1. The amount of alginate in Formulation C is equivalent to the amount of gelatin in Formulation P1. The results are shown in Table 9 below.

[0097] Table 9: Skin hydration and TEWL performance of a formulation of the present invention and a prior art formulation.

[0098] For skin hydration measurements, a higher value indicates the skin surface (stratum corneum) has higher hydration level. For TEWL, a lower value indicates a lower density gradient of the water evaporation from the skin (i.e. less water loss from the skin surface).

[0099] Formulation C is superior to Formulation P1 with respect to its longer-term effects on skin hydration. Formulation P1 appeared to result in a lower TEWL when comparing Day 4 active phase and the baseline (i.e. TEWL-). However, following a 4 day washout phase, the participants' hands donned with gloves coated with Formulation C showed better skin hydration and lesser water loss (TEWL) than hands donned with gloves coated with Formulation P1. This result shows that Formulation C displays superior longer-term effects on the participants' skin condition.

Claims

CLAIMS1 . A coating formulation comprising alginate, a hydrophilic polymer, a preservative and a solvent, wherein the alginate is present at an amount of from 0.1% to 2% by weight of the coating formulation, wherein the hydrophilic polymer is present at an amount of from 0.05% to 0.1% by weight of the coating formulation, wherein the preservative is present at an amount of from 0.05% to 0.1 % by weight of the coating formulation, and wherein the solvent is present at an amount of at least 97% by weight of the coating formulation.

2. The coating formulation as claimed in claim 1 , wherein the alginate is selected from the group consisting of sodium alginate, potassium alginate, calcium alginate, ammonium alginate, and a mixture of two or more thereof.

3. The coating formulation for claim 1 or 2, wherein the alginate is present at an amount of from 0.1 % to 1 .5% by weight of the coating formulation, for example from 0.1% to 1% by weight of the coating formulation.

4. The coating formulation as claimed in any one of claims 1 to 3, wherein the alginate is present at an amount of from 0.1% to 0.5% by weight of the coating formulation, for example about 0.34% by weight of the coating formulation.

5. The coating formulation as claimed in any one of the preceding claims, wherein the hydrophilic polymer is selected from the group consisting of a water-based silicone polymer, an acrylic-based copolymer, and a mixture of two or more thereof.

6. The coating formulation as claimed in claim 5, wherein the hydrophilic polymer is an acrylic-based copolymer.

7. The coating formulation as claimed in any one of the preceding claims, wherein the hydrophilic polymer is present at an amount of about 0.08% by weight of the coating formulation.

8. The coating formulation as claimed in any one of the preceding claims, wherein the preservative is selected from the group consisting of sodium benzoate,benzoic acid, calcium sorbate, erythorbic acid, potassium nitrate, and a mixture of two or more thereof.

9. The coating formulation as claimed in claim 8, wherein the preservative is sodium benzoate.

10. The coating formulation as claimed in any one of the preceding claims, wherein the preservative is present at an amount of about 0.08% by weight of the coating formulation.

11. The coating formulation as claimed in any one of the preceding claims, wherein the solvent is water.

12. The coating formulation as claimed in claim 11 , wherein the water is selected from the group consisting of soft water, distilled water, deionized water, tap water, ultrapure water and a mixture of two or more thereof.

13. The coating formulation as claimed in any one of the preceding claims, wherein the solvent is present at an amount of from 97.8% to 99.8% by weight of the coating formulation.

14. The coating formulation as claimed in claim 13, wherein the solvent is present at an amount of from 99.46% to 99.8% by weight of the coating formulation.

15. A method of preparing the coating formulation of any one of the preceding claims, said method comprising the steps of: a) adding alginate, a hydrophilic polymer and a preservative into a solvent to provide a mixture; b) stirring the mixture from step a) at a speed of from about 500 rpm to about 2000 rpm for about 15 minutes to about 60 minutes.

16. The method according to claim 15, wherein step b) comprising stirring the mixture from step a) and heating the mixture at temperature of from about 25 °C to about 40 °C.

17. A glove coated with the coating formulation of any one of claims 1 to 14.

18. The glove of claim 17, wherein the glove is a nitrile glove, a latex glove, a polyisoprene glove, or a polyvinyl glove.

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