KR20060134158A - On-line making of powder-free rubber gloves - Google Patents

Abstract

A powder-free medical glove having a first surface of a powder-free coagulant and a second surface with a polymer coating to ease donning. The powder-free coagulant on the first surface comprises micronized high-density polyethylene, a micro-emulsion of amino silicone, a dimethicone emulsion, calcium salts, an ethoxylated acetylenic diol surfactant and a cellulose thickener. The medical gloves are made in an on-line process of making latex articles that involves dipping hand-shaped formers into the coagulant before dipping them into the latex. The gloves are thereafter coated with a polymer to improve donnability before removal from the formers. The novel coagulant formulation permits easy removal of the articles from the formers, eases double-donning of gloves and eliminates the need for off-line processing.

Description

On-Line Manufacturing of Powder-Free Rubber Gloves {ON-LINE MAKING OF POWDER-FREE RUBBER GLOVES}

FIELD OF THE INVENTION The present invention relates to on-line methods of preparing powderless synthetic and natural rubber latex gloves by medical gloves and dipping, and methods and materials used to make these gloves. The present invention particularly relates to synthetic and natural latex medical gloves and other latex articles using powderless flocculants during the manufacturing process.

Various problems have arisen for gloves made from elastomeric materials such as natural rubber latex and synthetic latex. One important criterion for medical gloves is that they fit snugly in the wearer's hand. Natural rubber, due to its inherent high coefficient of friction, makes it difficult to wear gloves. To solve this problem, conventional medical gloves use a lubricant on the inner surface to facilitate wearing of the glove. Such lubricants also allow for easy removal of gloves from hand-shaped molds used in the manufacturing process. Typically, the lubricant is in powder form and is generally absorbent, for example starch powder is commonly used. However, there are doubts in the medical community about the use of loose dusting powder in gloves used in surgical procedures. As a result, many efforts have been made to reduce or eliminate the use of loose powders to facilitate the wearing of medical gloves by developing various powderless methods to improve wearability.

Synthetic latex and natural rubber gloves are typically used in a method of first immersing a hand tool or mandrel into a powder coagulant bath, immersing the tool into a latex or natural rubber bath, and finishing with a leaching and drying process. Is produced by. Often, gloves produced by this method result in gloves that tend to stick to the molding sphere after drying. When stripping gloves from the molding tool, gloves made by this method often stick and tear together.

In commercially manufactured gloves, the flocculant bath comprises a powder of mineral origin, providing a cohesion on the surface of the molding sphere. The non-tacky powder prevents the two layers of gloves from sticking together. The powder is usually calcium carbonate or talc because it can withstand the high temperatures (100-130 ° C.) used in the construction of latex gloves. On the outer surface, a starch or other powder layer is applied by immersing the molding tool with cured latex gloves into the starch slurry bath. Alternatively, the cured latex glove may be coated with a synthetic polymer coating to impart a tacky adhesion.

There are also disclosures relating to off-line chlorination, washing and silicone treatment processes for making powderless medical gloves. These processes remove talc and cornstarch powder residues, reduce tack and improve glove wear. However, these processes are usually labor intensive and use large amounts of water, which is expensive. Moreover, chlorination can lead to poor physical strength, discoloration and poor aging characteristics of gloves. In some cases, chlorination can cause storage and environmental hazards.

Preparation of powderless medical gloves using a chlorination process, polymer coating methods, or a combination of both is described in US Pat. 6,195,805; No. 5,674,818; No. 5,612,083; No. 5,570,475; No. 5,284,607; No. 5,088,125; No. 4,597,108 and 4,143,109. However, very few disclosures describe powderless glove manufacture without post-treatment or off-line steps such as chlorination, washing and / or silicone treatment. Among them, US Patent No. 6,075,081; No. 5,534,350 and No. 4,310,928 are disclosed.

Nile US Patent No. 6,075,081 discloses powderless flocculants for use in latex dipping processes, including salt-stable dispersions of polychloroprene rubber and inorganic metal salts. The flocculants of this disclosure may also contain powderless mold release agents including polypropylene wax emulsions and cationic surfactants to aid in the release of articles immersed from the molding tool.

Liu's US Patent No. 5,534,350 discloses an on-line powderless medical glove manufacturing method that facilitates stripping gloves from ceramic moldings using polyurethane polymers in a flocculant that acts as a waterproof lubricating layer. The polyurethane polymer coat on the inside of the glove improves wear.

Joung US Patent No. 4,310, 928 discloses coating a glove molding tool with a flocculant containing a lipo compound and a surfactant in a dispersion. These materials remain with the glove after the glove has been stripped from the molding, thereby providing a release surface for the glove.

Additionally, U.S. Patent No. Hassan et al. 6,378,137 discloses the manufacture of powderless medical gloves using a non-tacky composition of polymers or copolymers and waxes mixed with micronized high density polyethylene materials. This composition makes it easier to wear gloves. However, the gloves remain substantially powderless only in the finished product and require treatment of the silicone emulsion / wax mixture during off-line processing. US Patent No. of Hassan et al. 6,019,922 discloses a further powderless medical glove manufacturing method comprising a silicone treatment on the outer surface of the glove and a tacky composition on the inner surface of the glove. Non-tacky compositions of this reference include polymers or copolymers, micronized high density polyethylene materials, and waxes. However, in order to fabricate the gloves of this reference, the manufacturer must clean the finished gloves to remove residual coagulant powder. This cleaning process is not complete and results in a glove that is only substantially powder-free, not completely powder-free. The glove process of this disclosure also requires off-line processing, which involves treating the glove with a silicone solution to produce the finished product.

Therefore, it is desirable to have a powder-free, non-tacky glove with good wearability, which can be easily stripped from the glove forming tool after fabrication. In addition, such powder-free gloves preferably do not require minimal processing steps, most preferably off-line processing. Therefore, it would be desirable to provide a novel method of making powderless synthetic latex or natural rubber soaked gloves that solves the above problems of off-line processing. Embodiments of the present invention provide a novel coagulant composition that eliminates off-line processing because no calcium carbonate is used, resulting in off-line chlorination, washing and silicone treatment. As a result, the method lowers production costs and yields gloves that are completely powderless.

Summary of the Invention

According to one embodiment of the present invention, the powderless flocculant composition is used with synthetic polychloroprene latex during the on-line process to produce gloves that are powderless and do not require any off-line process. In particular, the process used to make such gloves, in one embodiment, prior to immersing the molding sphere into a natural rubber or synthetic latex composition, the hand molding sphere is micronized high density polyethylene, amino silicone micro-emulsion, dimethicone emulsion Immersion into a novel flocculant composition comprising a calcium salt, a surfactant, and a cellulose thickener.

In one embodiment, the method of making an article of the present invention comprises forming the preformed shaped spheres of salt-stable with micronized high density polyethylene, amino silicone micro-emulsions, dimethicone emulsions, acetylene diol surfactants and inorganic metal salts. Dipping into an aqueous powderless solution comprising an aqueous solution; Immersing the molding sphere in a polychloroprene latex dispersion to form a gelled latex film and to form a non-stick surface for the article; Leaching the gelled latex membrane; Treating the gelled latex membrane with a low-salt solution as a primer; Dipping the gelled latex film into the polymer coating; Drying the polymer coating; Curing the formed rubber article on a molding tool; And stripping the cured non-tacky article from the molding tool.

The polymer coating on the inside of the glove may be acrylic or polyurethane based and will be applied prior to curing. This coating can be further enhanced by immersing the cured glove into a silicon dip before removing the glove from the mold. This polymer coating, optionally with a silicone dip, will facilitate the wearing of the glove.

In accordance with the principles of the present invention, methods are provided for preparing powderless rubber or latex articles, in particular articles produced by conventional dipping processes, such as medical and surgical gloves, condoms and catheters.

1 illustrates a flow chart of an immersion process for preparing powder-free gloves on-line in accordance with an embodiment of the present invention.

Embodiments of the present invention provide the ability to change the grip properties of synthetic latex or natural rubber articles, particularly medical gloves, depending on the amount of dimethicone emulsion incorporated into the novel coagulant formulation. In one embodiment, the novel coagulant formulation will be on the outer surface of the glove at the end of the manufacturing process and will overlap to form a slippery surface that will improve the ability to double wear or to wear two pairs of gloves. .

Articles, in particular medical gloves, made in accordance with an embodiment of the present invention are formed by immersing a heated hand tool (smooth, patterned, or surface-shaped) into a novel flocculant composition. The novel coagulant compositions include micronized high density polyethylene, amino silicone micro-emulsions, dimethicone emulsions, calcium salts, ethoxylated acetylene diol surfactants and cellulose thickeners. The coagulant-coated moldings are then removed from the coagulant tank and immersed into a synthetic or natural elastomeric latex dispersion to form a gelled latex film. Preferably, the latex is polychloroprene latex. The gelled latex film is then leached and immersed into the polymer coating.

According to one embodiment of the present invention, the gelled latex glove is then cured on the mold before stripping the cured non-tacky article from the mold. In another embodiment of the present invention, the gelled latex glove is cured on the tool, and then immersed into a silicone dip before removing the glove from the tool. As described in this embodiment of the present invention, the polymer coating with a silicone dip will further facilitate wearing of the glove.

Preferably, the dimethicone-based silicone emulsion is prepared from a polydimethylsiloxane fluid having a viscosity at 25 ° C. ranging from about 10,000 to about 100,000 centistokes and an average molecular weight between about 62,700 and about 116,500.

Emulsions prepared from dimethicone fluids within these viscosity ranges, when incorporated into new flocculating formulations, will provide relatively small viscosity variations over a wide temperature range. The emulsion will provide good thermal / oxidative stability, chemical inertness and resistance to breakage under mechanical shear. They will also exhibit good antifriction properties on the exposed elastomeric surface of the glove in contact with the novel flocculant, which will make it easier to remove the glove from the molding during the manufacturing process.

Various emulsions and fluids prepared from dimethicone fluids are commercially available. For example, an emulsion made from a dimethicone fluid having a viscosity of about 10,000 centistokes is marketed under the trade name SM 2140 by GE Silicones, USA. Fluids made from the same base material are sold under the trade name VISCASIL 10M by GE Silicones, USA. An emulsion made from a dimethicone fluid having a viscosity of about 100,000 centistokes is sold under the trade name XS65-135891 by GE Toshiba Silicones Co. Ltd, Japan. Fluids made from the same base material are commercially available from GE Toshiba Silicones, Japan under the trade name TSF 451-10M. Dimethicone fluids ranging from about 10,000 to about 100,000 centistokes are classified as high viscosity fluids and are marketed under the trade name 200 FLUID by Dow Corning Corporation. Emulsions can also be prepared from mixtures of dimethicone and cyclomethicone, an example of such an emulsion being marketed under the trade name DOW CORNING Q2-1803 by Dow Corning.

The use of amino silicone micro-emulsions has been devised to create a glossy texture on the glove surface and to enhance the ductility of the glove. Amino silicone micro-emulsions are available under the trade name SOFTEX 5850 sold by Kao Industrial Companly Ltd (Thailand).

The use of micronized high density polyethylene can act as an anchor, improving not only the flocculant film application rate, but also facilitating stripping of the glove from the hand shaped tool. Micronized high-density polyethylene also provides gamma and stickiness to the outer surface of the glove (glove face that is in contact with the flocculant during the dipping process). Effective melting point ranges for high density polyethylene are typically between about 100 and about 130 ° C. The average particle size of the micronized high density polyethylene is typically between about 3 and about 12 microns.

Nonionic acetylene diol surfactants are normally used as wetting agents for flocculants, and cellulose thickeners are preferred for thickening flocculants.

Embodiments of the present invention will now be further described in the following examples, which are accompanied by a flow chart (FIG. 1) for manufacturing such articles in accordance with embodiments of the present invention.

Example 1

The ceramic earthenware sphere was heated to 60-70 ° C. and then immersed in a non-tacky coagulant dispersion at 25-35 ° C. for about 5-10 seconds. The flocculant dispersion contained:

Calcium nitrate 18 wt% Micronized HDPE 1 wt% Amino silicone micro-emulsion 1 wt% Cellulose thickener 0.2 wt% Acetylene diol surfactant 0.3 wt% water 79.5% by weight

For the formulation of Example 1, micronized HDPE is added as a 20% dispersion, amino silicone micro-emulsions are supplied as 20 to 22% emulsions, the cellulose thickener is diluted with a 1% solution and acetylene diol surfactants are supplied. Added as needed. After immersion in the coagulant dispersion, the ceramic molding sphere was slowly pulled out of the coagulant dispersion and rotated to uniformly distribute the coagulant throughout the molding sphere surface. The mold was then moved to an oven heated to 90 ° C. for about 90 seconds to dry the flocculant. After drying, the ceramic mold was immersed into the polychloroprene latex dispersion for about 20-30 seconds. This polychloroprene latex dispersion contained 40% dry polymer and was maintained at 25 ° C. Polychloroprene latex was deposited on the moldings, then spun up and heated in an oven at 75 ° C. for about 60 seconds. Next, the gelled polychloroprene latex was leached between 40 and 60 ° C. for about 180 seconds. Then, the polychloroprene polymer gel on the ceramic molding sphere was dipped into 1 to 2% salt solution primer before being immersed into the polyurethane or acrylic coating solution. The ceramic tool was then gradually dried between 110 and 140 ° C. for 35 minutes. The mold was then cooled before the glove was stripped from the tool. The mold can be reused during further production cycles by washing in acid and then water. The moldings were also easily cleaned with the standard cleaners used for glove dipping.

The gloves immersed using the powderless coagulant formulation of Example 1 were free of thin patches and were easily stripped from ceramic moldings. Glove grips were satisfactory and double gloving with gloves of the same type and size was satisfactory. This polychloroprene glove had a powderless property with a powder level of less than 2 mg per glove.

Example 2

According to Example 1, gloves were prepared in a similar procedure except for the cohesive flocculant composition. The non-tacky coagulant dispersion for this example contained the following:

Calcium nitrate 18 wt% Micronized HDPE 1 wt% Amino silicone micro-emulsion 1 wt% Dimethicone / cyclomethicone emulsion 0.1 wt% Cellulose thickener 0.2 wt% Acetylene diol surfactant 0.3 wt% water 79.4% by weight

In this example, the added dimethicone / cyclomethicone blend emulsion was fed as a 60% emulsion. The gloves produced in this example were well immersed without thin patches and easily stripped from the ceramic moldings. The glove grip was less aggressive than the glove prepared in Example 1, and double glove using good gloves of the same type and size was good. Polychloroprene gloves had a powderless property with powder levels of less than 2 mg per glove.

Example 3

According to Example 1, gloves were prepared in a similar procedure except for the cohesive flocculant composition. The non-tacky coagulant dispersion for this example contained the following:

Calcium nitrate 18 wt% Micronized HDPE 1 wt% Amino silicone micro-emulsion 1 wt% Dimethicone / cyclomethicone emulsion (100,000 centistokes) 0.1 wt% Cellulose thickener 0.2 wt% Acetylene diol surfactant 0.3 wt% water 79.4% by weight

In this example, the supplied dimethicone / cyclomethicone blend emulsion was prepared from a polydimethyl siloxane fluid having a viscosity of 100,000 centistokes measured at 25 ° C. The glove was well immersed without thin patches and easily stripped from the ceramic molding. The glove grip was slippery than all previous embodiments, and the double glove using the same type and size glove was excellent. Polychloroprene gloves had a powderless property with powder levels of less than 2 mg per glove.

Example 4

According to Example 1, gloves were prepared in a similar procedure except for the cohesive flocculant composition. The non-tacky coagulant dispersion for this example contained the following:

Calcium nitrate 18 wt% Micronized HDPE 1 wt% Amino silicone micro-emulsion 2 wt% Dimethicone / cyclomethicone emulsion (10,000 centistokes) 0.2 wt% Cellulose thickener 0.2 wt% Acetylene diol surfactant 0.3 wt% water 78.3 wt%

In this example, the supplied dimethicone emulsion was prepared from a polydimethyl siloxane fluid having a viscosity of 10,000 centistokes measured at 25 ° C. The glove was well immersed without thin patches and easily stripped from the ceramic molding. The glove grip was less slippery than the glove prepared in Example 3, and less aggressive than the gloves of Examples 1 and 2. Double glove of gloves of the same size and type was excellent. Polychloroprene gloves had a powderless property with powder levels of less than 2 mg per glove.

Example 5

According to Example 1, gloves were prepared in a similar procedure except for the cohesive flocculant composition. The non-tacky coagulant dispersion for this example contained the following:

Calcium nitrate 18 wt% Micronized HDPE 1 wt% Amino silicone micro-emulsion 2 wt% Dimethicone Emulsion (10,000 Centistokes) 0 wt% Cellulose thickener 0.2 wt% Acetylene diol surfactant 0.3 wt% water 78.5 wt%

Example 6

According to Example 1, gloves were prepared in a similar procedure except for the cohesive flocculant composition. The non-tacky coagulant dispersion for this example contained the following:

Calcium nitrate 18 wt% Micronized HDPE 1 wt% Amino silicone micro-emulsion 2 wt% Dimethicone Emulsion (10,000 Centistokes) 0.2 wt% Cellulose thickener 0.2 wt% Acetylene diol surfactant 0.3 wt% water 78.3 wt%

Example 7

According to Example 1, gloves were prepared in a similar procedure except for the cohesive flocculant composition. The non-tacky coagulant dispersion for this example contained the following:

Calcium nitrate 18 wt% Micronized HDPE 1 wt% Amino silicone micro-emulsion 2 wt% Dimethicone Emulsion (10,000 Centistokes) 0.4 wt% Cellulose thickener 0.2 wt% Acetylene diol surfactant 0.3 wt% water 78.1% by weight

The grip properties obtained by using different levels of dimethicone in Examples 5-7 are tabulated in Table 1. Grip properties were measured on a coefficient of friction tester manufactured by RJ Harvey Instrument Corporation, USA.

Rubber Friction Properties Measured on Coagulant Side Dimethicone Level Example 5 0% Dimethicone Example 6 0.2% Dimethicone Example 7 0.4% Dimethicone Gram force Coefficient of friction (COF) Gram force Coefficient of friction (COF) Gram force Coefficient of friction (COF) Rubber upper metal 229 182-318 1.15 0.91-1.59 187 142-242 0.94 0.71-1.21 144 115-208 0.72 0.58-1.04 Rubber upper rubber 152 157-266 0.76 0.79-1.33 135 119-162 0.68 0.60-0.81 121 112-145 0.61 0.56-0.73

As can be seen in Table 1, by varying the dimethicone level of the flocculant, the friction properties on the flocculant side of the polychloroprene rubber surface can be varied according to the grip characteristic requirements. All polychloroprene gloves of Examples 5-7 had powderless properties, with powder levels below 2 mg per glove.

Example 8

According to Example 1, gloves were prepared in a similar procedure except that the composition of the non-tacky coagulant and the polychloroprene latex dispersion of Example 1 were replaced with natural rubber latex. The non-tacky coagulant dispersion for this example was the same as used in Example 4.

Natural rubber gloves were well immersed without thin patches and were easily stripped from ceramic moldings. The glove grip was more aggressive than all the gloves of Examples 1-7. The rubber friction characteristics as measured using RJ Harvey instruments showed a metal on rubber (MR) value of about 250 gmf, which correlated with a COF value of 1.26. Natural rubber gloves had powder-free properties, with powder levels less than 2 mg per glove.

Example 9

The flocculant preparation and glove making procedures were similar to Example 8 except for the flocculant composition. The non-tacky coagulant dispersion for this example contained the following:

Calcium nitrate 18 wt% Micronized HDPE 2.5 wt% Amino silicone micro-emulsion 2.5 wt% Dimethicone Emulsion (10,000 or 100,000 centistokes) 0.4 wt% Cellulose thickener 0.2 wt% Acetylene diol surfactant 0.3 wt% water 76.1 wt%

Natural rubber gloves made from the formulations of this example were well immersed without thin patches and were easily stripped from ceramic moldings. Glove grips were less aggressive than those seen in gloves made using the formulation of Example 7. Double glove of gloves of the same size and type was satisfactory. Rubber friction properties as measured using RJ Harvey instruments showed an MR value of about 135 gmf or a COF value of 0.68. Natural rubber gloves from this example had a powder-free property with powder levels of less than 2 mg per glove.

Although the present invention has been described in conjunction with specific embodiments thereof, it is evident that alternatives, modifications and variations will be apparent to those skilled in the art in light of the above description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and broad scope of the appended claims.

Claims (16)

An elastomeric material having a first surface and a second surface, the first surface of the elastomeric material being coated with a powder-free coagulant coating (powder-free coagulant composition is micronized high density polyethylene; amino silicone micro-emulsion; dime Powdery elastomeric article, comprising a ticon emulsion; an ethoxylated acetylene diol surfactant; and a cellulose thickener), the second surface of the elastomeric material being coated with a polymeric coating. The powderless elastomeric article of claim 1, wherein the article is a glove. 3. The powderless elastomeric article of claim 2 wherein the elastomeric material is selected from the group consisting of polychloroprene, natural rubber, synthetic polyisoprene, carboxylated acrylonitrile butadiene and polyurethane. 4. The powderless elastomeric article of claim 3 wherein the elastomeric material is combined with a standard hardener. 5. The powderless elastomeric article of claim 4, wherein the second surface is halogenated. High density polyethylene with finely divided flocculants; Amino silicone micro-emulsions; Dimethicone emulsions; Calcium salts; Ethoxylated acetylene diol surfactants; And a cellulose thickener, wherein the cohesive flocculant composition is used to prepare a powderless elastomeric article. The cohesive flocculant composition of claim 6 wherein the mean melting point of the micronized high density polyethylene is between about 100 and about 130 ° C. and the average particle size is between about 2 and about 12 microns. 7. The non-tacky coagulant composition of claim 6 wherein the amino silicone micro-emulsion comprises mixed particles ranging in size from about 1 to about 100 microns. The cohesive flocculant composition of claim 6 wherein the dimethicone is emulsified from a polydimethyl siloxane fluid source having a viscosity in the range of about 10,000 to about 100,000 centistokes. The non-tacky coagulant composition according to claim 6, further comprising cyclomethicone. The non-tacky coagulant composition of claim 10 wherein the dimethicone in combination with the cyclomethicone is emulsified from a polydimethyl siloxane fluid source having a viscosity ranging from about 10,000 to about 100,000 centistokes. The method of claim 6, Calcium salt between about 10% and about 30%; Between about 0.1% and about 3% micronized HDPE; Amino silicone micro-emulsion between about 0.1% and about 3%; Dimethicone emulsion between about 0% and about 1%; Between about 0% and about 0.5% cellulose thickener; And A non-tacky coagulant composition further comprising a total solids content of nonionic acetylene diol surfactant between about 0.1% and about 0.5%. Forming a first layer of powder-free article by immersing the molding sphere into a bath of the non-tacky coagulant according to claim 6; Forming a second layer over the first layer by immersing the molding sphere into the modified elastomeric material; Gelling the second layer Leaching the gelled layer to remove soluble non-rubber or non-latex components; Subcontracting the second layer with a low salt concentration solution; Forming a third layer over the second layer by immersing the molding sphere into the polymer coating; Drying the third layer; Heat treating the formed layers between about 120 and about 160 ° C .; And A method of making a powderless article comprising post-leaching the cured forming layers. The method of claim 13, wherein the molding sphere is immersed into the cohesive flocculant at a temperature between about 20 and about 40 ° C. 15. A powderless elastomeric article produced by the powderless article manufacturing method according to claim 13. The powderless elastomeric article of claim 15, wherein the article is a glove.

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