WO2024076228A1

WO2024076228A1 - An anti-tack composition and a method for producing a non-tacky powder-free elastomeric article

Info

Publication number: WO2024076228A1
Application number: PCT/MY2023/050079
Authority: WO
Inventors: Kok Ho TEE
Original assignee: Ci Technology Sdn Bhd
Priority date: 2022-10-07
Filing date: 2023-10-04
Publication date: 2024-04-11
Also published as: WO2024076228A4

Abstract

The present invention discloses a method (100) for producing a non- tacky powder-free elastomeric article, the method (100) characterized by the steps of dipping a latex film in a solution comprising anti-tack particles (102) after a pre-leaching process, curing the latex film to entrap the anti-tack particles in the surface of the latex film for producing the non-tacky elastomeric article, wherein the anti-tack particles comprise clay minerals coated by secondary anti-tack materials. The present invention also discloses an anti-tack composition for a non-tacky powder-free elastomeric article, wherein the composition comprising clay mineral, metal salt of fatty acid and surfactant, optionally starch, wax, silicone, thickener or any combinations thereof.

Description

AN ANTI-TACK COMPOSITION AND A METHOD FOR PRODUCING A NON- TACKY POWDER-FREE ELASTOMERIC ARTICLE

FIELD OF THE INVENTION

The present invention relates to anti-tack coating for an elastomeric article, particularly an anti-tack composition and a method for producing a non- tacky powder-free elastomeric article.

BACKGROUND OF THE INVENTION

The extent of stickiness or tackiness of a synthetic or natural rubber relate to the number of unsaturated molecules. High number of unsaturated molecules results in more tackiness, and vice versa. The problem of tackiness in the thin rubber articles like dipped rubber causes poor donnability which then leads to unusable condition or uncomfortable when in use. The tackiness inside the glove results in shrinking of the glove and causes difficulty in opening up the glove and put on the hands. The outer tackiness of the glove results in sticking of the gloves when stacking and may lead to uncomfortable finger movement due to high friction between fingers caused by tackiness.

Nowadays, the glove thickness is getting thinner/smaller in view of the materials cost. In such case, tackiness of the glove affects the donnability and in extreme case the thin glove may tear off during donning. Therefore, various methods have been developed to remove tackiness in both inside and outside of the glove. Some of the examples will be discussed as below.

For inside of the glove, USP grade corn starch has been applied in a slurry form after curing and post-leaching for acting as an anti-tacking agent to avoid sticking inside the glove and ease the donning. It is known that corn starch carries natural protein. In the case of the natural rubber glove applied with the corn starch, corn starch dust tends to be released in the air and consequently create allergic reactions to the people that are allergic to the natural protein. Another disadvantage of using corn starch is the wearer’s hand will be coated with powder and messy. As for outer surface of the glove, calcium carbonate powder and metallic stearates salt are applied in the nitrile glove production to resolve the tackiness issue. Besides, off line chlorination is also being applied to remove sticking tendency on outer surface of the glove.

W02002032475A2 discloses a method of making a non-tacky powder- free neoprene article by dipping a former in a neoprene or neoprene copolymer latex comprises one or more anionic anti-tack to prevent any significant development of tack for a period of up to at least seven days when the article is stored at 70°C or at least 90 days when stored at 45°C, wherein the anti-tack is included in a latex formulation prior to formation of the article or, alternatively, or in addition, the article is washed in a solution of anti-tack agent after the article has been formed. However, the prior art uses non-biodegradable synthetic materials for polymer coating. Further, the polymer coating will bind to the base neoprene elastomer and thus may influence film properties.

US5178676A discloses an anti-tack composition and a method of reducing the tack of uncured rubber compounds. The method comprises a step contacting the surface of the uncured rubber with the anti-tack composition consisting essentially kaolin clay and a non-ionic surfactant via spraying for at least 5 seconds to provide a coating pickup value of said composition of 2.0% or less by weight. Applying anti-tack coat via spraying can maintain high quality finish. However, the anti-tack coat can easily be contaminated by the air contaminants.

US20030138579A1 discloses an article comprising a two-side treated formed rubber article and a process of making thereof. The method comprises the steps of immersing a glove former in an aqueous polymer composition, immersing the glove former in a coagulant to produce a coated former, immersing the coated former into a rubber latex, chlorinating the latex on the coated former, curing the chlorinated latex and removing the finished article from the former. The prior art combines polymer coating and chlorination to produce a powder-free glove with less tacky as well as good donnability and anti-blocking. However, the high consumption of synthetic polymer materials and chlorine are not environmentally friendly. Further, the large amount of the synthetic polymer materials and chlorine create chemical reaction with the latex film which leads to damage of the latex film.

Accordingly, there is a need to address the abovementioned issues by providing a non-reactive anti-tack composition and an improved method which can eliminate or minimize the use of reactive materials to produce a non-tacky powder-free elastomeric article with enhanced quality, good donnability and eco-friendly.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

It is an objective of the present invention to provide a method for producing a non-tacky powder-free elastomeric article by dipping a latex film in an anti-tack solution after pre-leaching, in which the latex film with the anti-tack coating is subjected to curing such that the anti-tack property is retained even after post-leaching.

It is also an objective of the present invention to provide a method which eliminates or requires only trace amount of polymer materials and chlorine in producing a non-tacky powder-free elastomeric article.

It is further an objective of the present invention to provide an anti-tack composition for a non-tacky powder-free elastomeric article, in which the antitack composition is made up of non-reactive materials which do not harm the environment.

It is yet another objective of the present invention to provide an elastomeric article which is eco-friendly in nature while fulfilling the anti-tack requirements of a dipped article. Accordingly, these objectives may be achieved by following the teachings of the present invention. The present invention discloses a method or producing a non-tacky powder-free elastomeric article, the method characterized by the steps of dipping a latex film in a solution comprising antitack particles after a pre-leaching process, curing the latex film to entrap the anti-tack particles in the surface of the latex film for producing the non-tacky elastomeric article, wherein the anti-tack particles comprise clay minerals coated by secondary anti-tack materials. The present invention also discloses an anti-tack composition for a non-tacky powder-free elastomeric article, wherein the composition comprising clay mineral, metal salt of fatty acid and surfactant, optionally starch, wax, silicone, thickener or any combinations thereof.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may have been referred by embodiments, some of which are illustrated in the appended drawings. However, it is to be noted that the appended drawing illustrates only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

The features, benefits, and advantages of the present invention will become apparent by reference to the following figures, with like, wherein:

Figure 1 is a flow diagram showing a method for producing a non-tacky powder-free elastomeric article in accordance with an embodiment of the present invention;

Figure 2 is a diagram illustrating the anti-tack coated film structure produced by dip coating in accordance with a preferred embodiment of the present invention; Figure 3 is a diagram illustrating the anti-tack and polymer coated film structure produced by dip coating followed by polymer coating in accordance with a second embodiment of the present invention;

Figure 4 is a diagram illustrating the anti-tack and chlorine coated film structure produced by dip coating followed by chlorination in accordance with a third embodiment of the present invention; and

Figure 5 is a diagram illustrating the anti-tack, polymer and chlorine coated film structure produced by dip coating followed by polymer coating and chlorination in accordance with a fifth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention is described herein by way of example using embodiments and illustrative drawings, those skilled in the art will recognize that the invention is not limited to the embodiments of drawing or drawings described, and are not intended to represent the scale of the various components. Further, some components that may form a part of the invention may not be illustrated in certain figures, for ease of illustration, and such omissions do not limit the embodiments outlined in any way. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claim. As used throughout this description, the word "may" is used in a permissive sense (i.e. meaning having the potential to), rather than the mandatory sense, (i.e. meaning must). Further, the words "a" or "an" mean "at least one” and the word “plurality” means “one or more” unless otherwise mentioned. Furthermore, the terminology and phraseology used herein is solely for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely to provide a context for the present invention. It is not suggested or represented that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention.

In this disclosure, whenever a composition or an element or a group of elements is preceded with the transitional phrase “comprising”, it is understood that we also contemplate the same composition, element or group of elements with transitional phrases “consisting of”, “consisting”, “selected from the group of consisting of, “including”, or “is” preceding the recitation of the composition, element or group of elements and vice versa.

The present invention is described hereinafter by various embodiments with reference to the accompanying drawing, wherein reference numerals used in the accompanying drawing correspond to the like elements throughout the description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. In the following detailed description, numeric values and ranges are provided for various aspects of the implementations described. These values and ranges are to be treated as examples only, and are not intended to limit the scope of the claims. In addition, several materials are identified as suitable for various facets of the implementations. These materials are to be treated as exemplary, and are not intended to limit the scope of the invention.

With reference to Figures 1 to 5, the invention will now be described in more detailed.

Figure 1 is a flow diagram showing the method (100) for producing a non-tacky powder-free elastomeric article in accordance to an embodiment of the present invention. The method (100) comprises conventional steps in the elastomeric article production process, the conventional steps include cleaning a former, drying the former, dipping the former in coagulant, drying the former with coagulant, dipping the former into a latex compound to obtain a latex film, gelling the latex film, optionally repeating the dipping and gelling, pre-leaching, beading, curing the latex film, post-leaching, drying and stripping.

In accordance with a preferred embodiment of the present invention, the distinctiveness of the method (100) for producing the non-tacky powder-free elastomeric article lies on dipping the latex film in a solution comprising antitack particles (102) after the pre-leaching, curing the latex film to entrap the anti-tack particles in the surface of the latex film for producing the non-tacky elastomeric article, wherein the anti-tack particles comprise clay minerals. More specifically, the clay minerals are further coated by secondary anti-tack materials comprised of metal salt of fatty acid and surfactant, optionally, starch, wax, silicone, thickener or any combinations thereof. The coating of secondary anti-tack materials keeps the clay minerals loosely entrapped in the surface of the latex film thereby preventing the clay minerals from attaching themselves with the latex film. During the anti-tack dipping (102), the anti-tack particles are partially or fully entrapped in the outer surface of the latex film. The anti-tack particles get trapped in the surface of the latex film during curing. In other words, the method of the present invention ensures the adherence of the antitack particles to the latex film using the curing characteristics of the latex film. Furthermore, the anti-tack coating is not reacting with the latex film and thus making the anti-tack coating washable. Due to the anti-tack particles are entrapped in the surface of the latex film during curing, the anti-tack property is able to be retained even after washing in post-leaching.

In accordance with a second embodiment of the present invention, the method (100) for producing the non-tacky powder-free elastomeric article further comprises subjecting the latex film to polymer coating (104) after antitack dipping (102) and prior to beading and curing, wherein polymer coating comprises polyacrylic, polyurethane, polyacrylate, poly-styrene acrylate or any combinations thereof, in a concentration of 0.01 to 8.0% w/v. In accordance with a third embodiment of the present invention, the method (100) for producing the non-tacky powder-free elastomeric article further comprises the step of subjecting the latex film to chlorination (106) after anti-tack dipping, beading and curing, wherein the chlorination comprises chlorine with a concentration less than 500 ppm. Optionally, the latex film can be subjected to cooling prior to chlorination. Optionally, the chlorinated latex film can further be subjected to neutralization after chlorination.

In accordance with a fourth embodiment of the present invention, the method (100) for producing the non-tacky powder-free elastomeric article further comprises the step of subjecting the latex film to a second anti-tack dipping (108) or slurry overcoat after the first anti-tack dipping, beading, curing and post-leaching.

In accordance with a fifth embodiment of the present invention, the method (100) for producing the non-tacky powder-free elastomeric article further comprise the steps of subjecting the latex film to polymer coating (104) before beading and curing, chlorination (106) after curing and second anti-tack dipping (108) after curing and post-leaching.

The present invention also discloses an anti-tack composition for a non- tacky powder-free elastomeric article.

In accordance with an embodiment of the present invention, the composition comprises clay mineral, metal salt of fatty acid and surfactant.

In accordance with an embodiment of the present invention, the composition further comprises starch, wax, silicone, thickener or any combinations thereof.

In accordance with an embodiment of the present invention, the clay mineral is hydrous aluminium phyllosilicates comprise transition metals, alkali metals, alkaline earth metals or any combinations thereof, in a concentration of 0.05 to 5.0% w/v with a particle size less than 15.0 pm so that the particles properly function as anti-tacking agent upon partial encapsulation as well as not hindering the ease of donning. More preferably, the clay mineral is in a concentration of 0.30 to 0.40% w/v with a particle size of 0.1 to 8.0 pm, wherein the clay mineral preferably but is not limited to sodium aluminium silicate base clay mineral.

In accordance with an embodiment of the present invention, the metal salt of fatty acid comprises metal hydroxide and unsaturated fatty acid, in a concentration of 0.1 to 3.0% w/v. More preferably, the metal salt of fatty acid is in a concentration of 0.5 to 0.6% w/v. More particularly, the metal oxide comprises metal selected from potassium, magnesium, calcium, zinc or any combinations thereof. More particularly, the unsaturated fatty acid comprises caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid or any combinations thereof. The metal salt of fatty acid preferably but is not limited to calcium stearate and potassium stearate.

In accordance with an embodiment of the present invention, the surfactant comprises non-ionic surfactant, anionic surfactant or combination thereof, in a concentration of 0.1 to 1.0% w/v. More preferably, the surfactant is anionic surfactant in a concentration of 0.2% w/v, wherein the surfactant preferably but is not limited to sodium laureth sulphate and sodium dodecyl benzene sulphate.

In accordance with an embodiment of the present invention, the starch is in a concentration of 0.1 to 3.0% w/v. More preferably, the starch is in a concentration of 0.20 to 0.30% w/v.

In accordance with an embodiment of the present invention, the wax comprises natural wax, synthetic wax or combination thereof, in a concentration of 0.05 to 3.00% w/v. More preferably, the natural wax in a concentration of 0.10 to 0.20% w/v, wherein the natural wax preferably but is not limited to paraffin-based wax and vegetable-based wax. In accordance with an embodiment of the present invention, the silicone comprises amino silicone, dow corning silicone, regular dimethicone silicone or any combinations thereof, in a concentration of 0 to 2.0% w/v. More preferably, the silicone is amino silicone in a concentration of 0.05 to 0.50% w/v.

In accordance with an embodiment of the present invention, the thickener comprises sodium polyacrylate, hydroxyl ethyl cellusose or combination thereof, in a concentration of 0.01 to 0.80% w/v. More preferably, sodium polyacrylate thickener in a concentration of 0.10 to 0.30% w/v.

In accordance with an embodiment of the present invention, the elastomeric article is a glove having the anti-tack particles coated in the inner surface, wherein the elastomeric article is made up of natural rubber, synthetic rubber, blend of natural and synthetic or blend of various synthetic rubbers.

Figure 2 is a diagram illustrating the anti-tack coated film structure produced by dipping the latex film in the solution comprising anti-tack particles (102) in accordance with a preferred embodiment of the present invention. The clay particles are partially and could be fully also encapsulated in the outer surface of the latex film during dipping. If the latex article is a glove, the coating will be presented in the inner surface of the glove at the donning side after stripping from the former. The coating on the clay particles could be comprised of metal salt of fatty acid and surfactants. Optionally, the coating on the clay particles could also be comprised of starch, wax, silicone and thickener. In comparison with the reactive materials in the conventional polymer coating and chlorination, the non-reactive anti-tack composition of the present invention does not have any capability to react with the latex film. For instance, the antitack particles do not form bonding onto the latex film compare to the conventional chlorinated latex film that has a direct chlorine bonding as a result of reaction takes place. Nevertheless, the anti-tack composition of the present invention has some physical adhesion of non-permanent nature to get entrapped in the latex film at wet and non-curing state. Also, the anti-tack composition of the present invention gets physically attached and entrapped during curing of the latex film. The non-reactive nature of the coating material and process neither disturb the curing of the latex film nor make permanent change like crosslinking pattern in the latex film upon completion of the operation. Other than the inner surface of the latex film, the anti-tack composition of the present invention is also feasible to be applied to the outer surface of the latex film during coagulant dipping with addition of calcium nitrate. The anti-tack composition of the present invention is not permanently bonded with the latex film. Therefore, the coating could be removed physically by normal cleaning after the glove has been stripped off from the former.

Figure 3 is a diagram illustrating the anti-tack and polymer coated film structure produced by dipping the latex film in the solution comprising anti-tack particles (102) followed by polymer coating (104) in accordance with a second embodiment of the present invention. After the latex film has coated with the non-reactive anti-tack composition of the present invention, an optional polymer coating could be carried out by applying at low amount of synthetic polymer to form a very thin layer on the surface of the latex film. The non-reactive anti-tack composition acts as a cushion in between the polymer layer and the latex film to obstruct the polymer layer bonds on the latex film. Therefore, the consumption of synthetic polymeric material could be significantly reduced by applying the anti-tack coating prior to the polymer coating while fulfilling the needs of required anti-tack properties for specific applications. The advantages of this option are low consumption of synthetic polymeric material minimizing the side effect of synthetic polymer, and low adherence or no adherence to the latex film depending on the conditions set by the anti-tack composition. For single use disposable dipped elastomeric article, such a weak polymer coating serves as a purpose of one-time donning and non-tackiness during storage of the article.

Figure 4 is a diagram illustrating the anti-tack and chlorine coated film structure produced by dipping the latex film in the solution comprising anti-tack particles (102) followed by chlorination (106) in accordance with a third embodiment of the present invention. After the latex film has coated with the non-reactive anti-tack composition of the present invention, an optional mild chlorination could be carried out to form a very thin layer on the surface of the latex film. The consumption of chlorine could be significantly reduced by applying the anti-tack coating prior to the chlorination while fulfilling the needs of required anti-tack properties for specific applications. The advantages of this option are low consumption of chlorine gas, low reaction and less coupling of chlorine molecules to the latex film depending on the conditions set by the composition of the anti-tack composition and chlorine concentration in the chlorination bath. For single use disposable dipped elastomeric article, such a weak chlorination serves as a purpose of one-time donning and non-tackiness during storage of the article. The hybrid form of the anti-tack application compositing the base elastomer with non-reactive anti-tack composition and chlorine rendering space occupied by the clay particles and other non-reactive materials to avoid the attachment of the chlorine molecule on the elastomer surface.

Figure 5 is a diagram illustrating the anti-tack, polymer and chlorine coated film structure produced by dipping the latex film in the solution comprising anti-tack particles (102) followed by polymer coating (104) and chlorination (106) in accordance with a fifth embodiment of the present invention. After the latex film has coated with the non-reactive anti-tack composition of the present invention, an optional polymer coating (104) could be applied. Upon beading and curing, an optional mild chlorination (106) could be carried out over the polymer coating (104). The advantages of this option are low consumption of synthetic polymeric material and chlorine, low adherence or no adherence of the polymer layer and chlorine to the latex film thereby minimizing damage to the latex film and less discoloration.

Hereinafter, an example of the present invention will be provided for a more detailed explanation and comparative study. The advantages of the present invention may be more readily understood and put into practical effect from this example. However, it is also to be understood that the following example do not limit the scope of the present invention in any way. Example

84 sets of experiments were carried out according to the flowchart as shown in Figure 1 to evaluate the performance of the elastomeric film produced using the method (100) and the anti-tack composition of the present invention. The evaluation was done by visual observation for powder mark, coating evenness, oiliness, surface roughness, tendency to stick in before aging (BA) and after aging (AA) conditions. The after aging condition is stimulated by keeping the elastomeric film under a weight of 1 kg at a temperature of 100°C for 1 hour. The aged elastomeric film was evaluated for sticking tendency and donning characters. Tables 1 and 2 below show the abbreviation given to the chemical components and donning performance rating which will be used in the result tables for easy understanding.

Table 1 : Abbreviation of the chemical components

Table 2: Abbreviation of the donning performance rating

Results and Discussion

The anti-tack compositions and the results for 84 sets of experiments are shown in Tables 3 to 1 3. The units given to the chemical components of the anti-tack composition are percentage to the total solution weight of 100 (% w/v).

Table 3: Results of experiments 1 to 9

Table 3 shows the anti-tack compositions and results of experiments 1 to 9 with calcium stearate in a concentration from 0.375 to 1 .5% w/v. Experiment 1 and 2 did not comprise clay whereas experiments 3 to 9 comprises clay. Paraffin wax and silicone were present in all the experiments 1 to 9. The results show that elastomeric film in Experiment 5 gave better performance and this could be due to the presence of clay in the anti-tack composition of both first anti-tack coating and the second anti-tack coating. Excess thickener in the first anti-tack coating and excess clay in the second anti-tack coating results in powder mark which is obvious. Experiments 4, 6 and 8 were satisfactory with respect to donning even without second anti-tack coating implying that the first anti-tack coating is sufficient for the practical purposes for producing non-tacky glove with better donning. Meanwhile, the mild powder mark in experiment 6 and 8 could be due to absence of silicone as well as introduction of thickener in experiment 8 which was intended to improve pick up of anti-tack coating and resulted in more powder retention on the elastomeric film.

Table 4: Results of experiments 10 to 15

Table 4 shows the anti-tack compositions and results of experiments 10 to 15. In this set up variations with respect to calcium stearate, wax, silicone and other items were tried. All the results in experiments 10 to 15 were not satisfactory, this could be due to non-presence of clay or less clay. Moreover, the presence of calcium carbonate resulted in very powdery product. These experiments are to be taken as a learning curve for the possible best conditions ahead. Table 5: Results of experiments 16 to 19

Table 5 shows the anti-tack compositions and results of experiments 16 to 19. In this set up variations with respect to clay and other chemical components were tried. All the results in experiments 16 to 19 were not satisfactory. The presence of starch resulted in very sticky product. These experiments are to be taken as a learning curve for the possible best conditions ahead.

Table 6: Results of experiments 20 to 25

Table 6 shows the anti-tack composition and results of experiments 20 to 25. The donning results were satisfactory for the experiments 20 to 22 and 25 even though there was mild sticky. Experiments 24 and 25 comprise same anti-tack composition in the first coating but different anti-tack composition in the second coating. The results revealed that the elastomeric film in experiment 25 was less sticky and exhibited good donning compared to the elastomeric film in experiment 24. Table 7: Results of experiments 26 to 35

Table 7 shows the anti-tack composition and results of experiments 26 to 35. The results of 34 and 35 were very good and distinct change is that amino silicone is not present in these two sets of experiments. However, starch was present in all sets of experiments in a concentration of 0.3% w/v. The reduction of calcium stearate and clay in experiments 28 and 29 compared to 26 and 27 resulted more sticky and poor donning characteristics. Meanwhile, the second coating does not have any effect in experiments 26 to 29. Besides, Lutensol did not have any significant effect towards the performance of the elastomeric film.

Table 8: Results of experiments 36 to 45

Table 8 shows the anti-tack composition and results of experiments 36 to 45. The anti-tack composition of first coating comprises equal amount of calcium stearate, thickener and surfactant for all sets of experiments. Experiment 37 shows the best result out of all sets of experiments.

Table 9: Results of experiments 46 to 55

Table 9 shows the anti-tack composition and results of experiments 46 to 55. Experiment 55 shows the best result out of all sets of experiments. One of the important differences is the use of multiple metallic stearates in combination with the second coating. The result of experiment 47 was satisfactory even without metallic stearate and silicone. These results indicate that second coating enables better performance.

Table 1 0: Results of experiments 46 to 64

Table 1 0 shows the anti-tack composition and results of experiments 56 to 64. All sets of the experiments comprise starch, surfactant, clay, wax and cellulose type thickener. The results of experiments 60 to 62 shows better performance.

Table 1 1 : Results of experiments 65 to 74

Table 1 1 shows the anti-tack composition and results for experiments 65 to 74. All sets of experiments comprise calcium stearate, clay, wax, starch and surfactant. The result of experiment 66 shows the best performance out of all other sets of experiments. Table 1 2: Results of experiments 76 to 84

Table 1 2 shows the anti-tack composition and results of experiments 76 to 84. All sets of experiments comprise calcium stearate, wax, clay, starch and surfactant. The polymer coating was applied after first coating in experiments 77, 78 and 82. The chlorination was applied after curing chlorination in experiments 81 to 84. Notably, experiment 82 comprises first anti-tack coating, polymer coating, chlorination and second coating. In experiments 76, 78, 80 and 82, polymer was included in the second coating. All the final results have same performance rating with respect to visual and donning aspects. These results indicate that the anti-tack composition and methods (100) of the present invention is feasible to produce the anti-tacky powder-free glove with good donning characteristic.

The method (100) of the present invention allows the anti-tack particles to be first entrapped on the outer surface of the latex film by dipping it in the anti-tack solution and then further utilizes the curing characteristic of the latex film to ensure adherence of the anti-tack particles to the latex film. Hence, the anti-tack tendency is able to retain even after washing in the post-leaching process. Moreover, the present invention eliminates or minimizes the use of synthetic polymeric materials and chlorine to solve the environmental problem caused by conventional polymer coating and chlorination. Additionally, the present invention address the allergic issue by providing the anti-tack composition that is non-reactive and skin friendly.

Various modifications to these embodiments are apparent to those skilled in the art from the description and the accompanying drawings. The principles associated with the various embodiments described herein may be applied to other embodiments. Therefore, the description is not intended to be limited to the embodiments shown along with the accompanying drawings but provides the broadest scope consistent with the principles and the novel and inventive features disclosed or suggested herein. Accordingly, the invention is anticipated to hold on to all other such alternatives, modifications, and variations that fall within the scope of the present invention and appended claim.

Claims

1. A method (100) for producing a non-tacky powder-free elastomeric article, the method (100) characterized by the steps of: dipping a latex film in a solution comprising anti-tack particles (102) after a pre-leaching process; curing the latex film to entrap the anti-tack particles in the surface of the latex film for producing the non-tacky elastomeric article; wherein the anti-tack particles comprise clay minerals coated by secondary anti-tack materials.

2. The method (100) for producing the non-tacky powder-free elastomeric article as claimed in claim 1 , wherein the latex film is further subjected to polymer coating (104) before curing.

3. The method (100) for producing the non-tacky powder-free elastomeric article as claimed in claim 1 , wherein the latex film is further subjected to chlorination (106) after curing.

4. The method (100) for producing the non-tacky powder-free elastomeric article as claimed in claim 1 or 3, wherein the latex film is further subjected to a second anti-tack dipping (108).

5. The method (100) for producing the non-tacky powder-free elastomeric article as claimed in claim 1 , wherein the latex film is further subjected to polymer coating (104) before curing, chlorination (106) and second antitack dipping (108) after curing.

6. The method (100) for producing the non-tacky powder-free elastomeric article as claimed in claim 1 , wherein the secondary anti-tack materials comprise metal salt of fatty acid and surfactant.

7. The method (100) for producing the non-tacky powder-free elastomeric article as claimed in claim 6, wherein the secondary anti-tack materials further comprises starch, wax, silicone, thickener or any combinations thereof.

8. The method (100) for producing the non-tacky powder-free elastomeric article as claimed in claim 2 or 5, wherein the polymer coating (104) comprises polyacrylic, polyurethane, polyacrylate, poly-styrene acrylate or any combinations thereof, in a concentration of 0.01 to 8.0% w/v.

9. The method (100) for producing the non-tacky powder-free elastomeric article as claimed in claim 3 or 5, wherein the chlorination (106) comprises chlorine with a concentration less than 500 ppm.

10. A non-tacky powder-free elastomeric article produced according to any of the claims 1 to 9, wherein the elastomeric article is a glove having anti-tack particles coated in the inner surface.

11.An anti-tack composition for a non-tacky powder-free elastomeric article, the composition comprising clay mineral, metal salt of fatty acid and surfactant.

12. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 11 , wherein the anti-tack composition further comprises starch, wax, silicone, thickener or any combinations thereof.

13. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 11 , wherein the clay mineral is hydrous aluminium phyllosilicates comprise transition metals, alkali metals, alkaline earth metals or any combinations thereof, in a concentration of 0.05 to 5.0% w/v.

14. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 11 , wherein the clay mineral is in a particle size less than 15.0 pm.

15. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 11 , wherein the metal salt of fatty acid comprises metal hydroxide and unsaturated fatty acid, in a concentration of 0.10 to 3.0% w/v.

16. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 15, wherein the metal hydroxide comprises metal selected from potassium, magnesium, calcium, zinc or any combinations thereof.

17. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 15, wherein the unsaturated fatty acid comprises caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid or any combinations thereof.

18. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 11 , wherein the surfactant comprises nonionic surfactant, anionic surfactant or combination thereof, in a concentration of 0.10 to 1 .0% w/v.

19. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 12, wherein the starch is in a concentration of 0.1 to 3.0% w/v.

20. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 12, wherein the wax comprises natural wax, synthetic wax or combination thereof, in a concentration of 0.05 to 3.0% w/v. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 12, wherein the silicone comprises amino silicone, dow corning silicone, regular dimethicone silicone or any combinations thereof, in a concentration of 0 to 2.0% w/v. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in claim 12, wherein the thickener comprises sodium polyacrylate, hydroxyl ethyl cellusose or combination thereof, in a concentration of 0.01 to 0.8% w/v. The anti-tack composition for the non-tacky powder-free elastomeric article as claimed in any of the claims 11 to 22, wherein the non-tacky powder-free elastomeric article is a glove having the clay minerals coated in the inner surface.