Patent Description:
The development of synthetic rubber materials have made possible the manufacture of a wide variety of elastomeric articles having varying properties of strength and chemical resistance. Among these articles are gloves designed for use in various industries, such as the medical, pharmaceutical, and electrical component manufacturing and handling fields. As safety accessories, the gloves protect a user from environmental hazards such as chemicals or pathogens. Relatively thin and flexible gloves have traditionally been made of natural rubber latex in a dipping process. The donning surface (i.e., the interior) of these gloves may be coated with corn starch, talcum, or lypcopodium powder to lubricate the gloves, making them easier to don. In recent years, powder-free gloves have largely replaced powdered gloves because of changing needs and perceptions of glove consumers. Powders, for example, are often unsuitable for clean rooms such as those used in the manufacture of semiconductors and electronics.

Glove consumers have also been moving away from natural rubber gloves due, in part, to an increasing rate of allergic reactions, and to anxiety of potentially developing allergic reactions, to proteins in natural rubber latex among health professionals as well as the general population. The industry has increasingly moved to latex emulsions based on synthetic rubber materials. While hospitals, laboratories, or other work environments that use rubber gloves often want to go "latex free" to protect workers and to alleviate anxiety, the higher cost of nonlatex products, such as nitrile rubber, often limits their ability to make the change. For example, nitrile rubber gloves may cost two or more times the price of the natural rubber latex or vinyl-based counterparts. This increased cost has often caused purchasers in cost-sensitive environments either to switch to less expensive polyvinyl chloride gloves, or has prevented them from switching to the synthetic materials altogether.

In addition to being more expensive, nitrile-butadiene rubber gloves are typically stiffer and are perceived as being much less comfortable to wear in comparison to similar gloves made from natural rubber latex materials. For instance, natural rubber latex (NRL) gloves typically require a stress of about <NUM> MPa (<NUM> psi) to stretch to an elongation of about <NUM> percent of its original dimensions. This often is referred to as the glove's <NUM> percent modulus. Nitrile rubber gloves, on the other hand, typically require more than twice that amount of stress (~<NUM>-<NUM> MPa, ~<NUM>-<NUM> psi) to achieve the same <NUM> percent elongation. Thus, donning of nitrile rubber gloves over prolonged periods of time may result in hand fatigue to a user. While polyvinyl chloride medical exam gloves can be inexpensive, polyvinyl chloride medical exam gloves are typically considered a lower performance choice. That is, polyvinyl chloride medical exam gloves are typically stiffer and less elastomeric than even the conventional thicker nitrile rubber medical exam gloves.

Other considerations in the selection of industrial or medical gloves are tactile sensitivity and specific chemical resistance to hazardous materials. For example, many users require gloves that provide a combination of tactile sensitivity that enables them to perform tasks and to use tools with precise dexterity, and of protection from hazardous materials for up to several hours of use. Thicker gloves generally have enhanced chemical resistance and reduced tactile sensitivity, while thinner gloves generally have reduced chemical resistance and enhanced tactile sensitivity.

Thus, there remains a need for a disposable elastomeric glove that is affordable, and that provides enhanced tactile sensitivity and protection to a user.

According to the invention, an elastomeric glove comprises a body-facing layer of a first elastomeric material, a middle layer of a second elastomeric material, and an outer layer of a third elastomeric material different than at least the second elastomeric material. The third elastomeric material has an acrylonitrile content greater than at least the second elastomeric material.

According to the invention, an elastomeric glove comprises a glove body including a cuff region, a finger region, and a palm region. The glove body includes a body-facing layer of an accelerator-free elastomeric material, a middle layer of a natural rubber latex material, and an outer layer of a high acrylonitrile nitrile material. The body-facing layer, the middle layer, and the outer layer of material have a combined thickness of less than about <NUM> millimeters in the palm region of the glove body.

The invention further relates to a method of fabricating said elastomeric glove, the method comprising dipping a hand-shaped former into a first dip tank containing the third elastomeric material such that a first layer of the third elastomeric material is formed on the hand-shaped former; dipping the hand-shaped former into a second dip tank containing the second elastomeric material such that a second layer of the second elastomeric material is formed over the first layer; and dipping the hand-shaped former into a third dip tank containing the first elastomeric material such that a third layer of the first elastomeric material is formed over the second layer. The first elastomeric material has an acrylonitrile content greater than at least the second elastomeric material.

Turning now to the drawings, <FIG> illustrate one suitable embodiment of an elastomeric glove, indicated generally at <NUM>, of the present disclosure. The glove <NUM> seen in <FIG> is illustrated being donned by a user <NUM>. The glove <NUM> includes a glove body <NUM> having a cuff region <NUM>, a finger region <NUM>, and a palm region <NUM> located between the cuff region <NUM> and the finger region <NUM>. The finger region <NUM> is defined by a plurality of fingers <NUM>, with each of the five fingers <NUM> having a base <NUM> and a fingertip <NUM>. As described herein, the palm region <NUM> includes an area on the glove body <NUM> extending between the cuff region <NUM> and the bases <NUM> of the fingers <NUM>. The glove <NUM> may be designed to be ambidextrous, or may be designed for left-handed or right-handed use only.

The glove <NUM> may also have any suitable length L (shown in <FIG>) based on its intended use. For example, the glove <NUM> may be intended for use in a medical, dental, pharmaceutical, electrical, or clean room setting. In one suitable embodiment, the length L of the glove <NUM> is between about <NUM>,<NUM> (<NUM> inches) and about <NUM>,<NUM> (<NUM> inches), between about <NUM>,<NUM> (<NUM> inches) and about <NUM>,<NUM> (<NUM> inches), between about <NUM>,<NUM> (<NUM> inches) and about <NUM>,<NUM> (<NUM> inches), or between about <NUM>, <NUM> (<NUM> inches) and about <NUM>,<NUM> (<NUM> inches). In the illustrated embodiment, for example, the length L of the glove <NUM> is approximately <NUM>,<NUM> (<NUM> inches). In other suitable embodiments, the length L of the glove <NUM> can be equal to or greater than about <NUM>,<NUM> (<NUM> inches) without departing from some aspects of the disclosure. In such an embodiment, the length L of the glove body <NUM> is increased such that the cuff region <NUM> covers a larger portion of the arm of the user <NUM> compared to a glove having a shorter length.

Turning now to <FIG>, the glove body <NUM> includes a body-facing layer <NUM>, a middle layer <NUM>, and an outer layer <NUM>. Each layer <NUM>, <NUM>, and <NUM> is fabricated from any suitable elastomeric material that enables the glove <NUM> to function as described herein. As used herein, the term "elastomeric material" refers to a material that is stretchable to an elongation of at least about <NUM> percent of its relaxed length, i.e., can be stretched to at least about one and one-quarter times its relaxed length, and upon release of the stretching force will recover at least about <NUM> percent of the elongation.

In general, the glove <NUM> is formed in a dipping process using a series of compositions, such as a coagulant composition and an elastomeric composition, as needed to attain the desired glove characteristics. The layers formed from the compositions may be allowed to solidify before additional layers are formed. Any combination of layers may be used, and although specific layers are described herein, it should be understood that other layers and combinations of layers may be used as desired.

To fabricate the body-facing layer <NUM>, any suitable coagulant composition and elastomeric material may be used that facilitates providing comfort to the user <NUM>, but that does not cause an allergic reaction or contribute to anxiety of potentially developing an allergic reaction of the user <NUM> donning the glove <NUM>. Thus, the coagulant composition is powder-free, thereby rendering the glove <NUM> and the body-facing layer <NUM> likewise powder-free per ASTM D6124 and EN455-<NUM>.

In addition, the elastomeric material of the body-facing layer <NUM> is accelerator-free. Accelerators are compounds sometimes included in a bath of elastomeric material for use in facilitating vulcanization of the elastomeric material. However, the presence of accelerators may cause an adverse reaction in users of articles formed from the elastomeric material including an accelerator. The reaction is commonly referred to as a Type IV allergy, which generally occurs within <NUM> to <NUM> hours of contact with the article and that is localized to the area of the skin where contact is made. Preparing a bath of the elastomeric material, for use in fabricating the body-facing layer <NUM>, that is accelerator-free facilitates reducing or substantially eliminating adverse reactions to the user <NUM> donning the glove <NUM>.

Suitable examples of the elastomeric material used to form the body-facing layer <NUM> include, but are not limited to, neoprene, nitrile, butyl, elastane, polychloroprene, styrene-butadiene rubber, and polyisoprene. The elastomeric material is devoid of natural rubber latex. As such, the body-facing layer <NUM> contains less than about <NUM> micrograms/gram of protein, or less than about <NUM> micrograms/gram of protein.

To fabricate the middle layer <NUM>, any suitable coagulant composition and elastomeric material may be used that facilitates providing comfort and dexterity to the user <NUM> donning the glove <NUM>. That is, the elastomeric material is selected such that the middle layer has a <NUM> percent modulus value less than that of the outer layer <NUM>. As such, the middle layer <NUM> facilitates increasing the flexibility and perceived comfort of the glove <NUM>. Suitable examples of the elastomeric material used to form the middle layer <NUM> include, but are not limited to, natural rubber latex, neoprene, nitrile, butyl, elastane, polychloroprene, styrene-butadiene rubber, and polyisoprene.

As illustrated in <FIG>, the middle layer <NUM> is encapsulated by the body-facing layer <NUM> and the outer layer <NUM>. As such, the illustrated configuration enables the middle layer <NUM> to be fabricated from natural rubber latex so as to provide the desired comfort and dexterity inherent to natural rubber latex without exposing the user <NUM> to potential allergens.

To fabricate the outer layer <NUM>, any suitable coagulant composition and elastomeric material may be used that facilitates forming a layer that provides physical and chemical protection to the user <NUM>, but that does not cause an allergic reaction or contribute to anxiety of potentially developing an allergic reaction of the user <NUM> donning the glove <NUM>. Thus, the coagulant composition is powder-free, thereby rendering the glove <NUM> and the outer layer <NUM> likewise powder-free per ASTM D6124 and EN455-<NUM>. In one suitable embodiment, the elastomeric material is a high acrylonitrile nitrile material. As used herein, "high acrylonitrile nitrile" refers to a polymeric material having an acrylonitrile content greater than <NUM> percent, defined within a range between <NUM> percent and <NUM> percent, defined within a range between about <NUM> percent and about <NUM> percent, or defined within a range between about <NUM> percent and about <NUM> percent by weight.

The elastomeric material of the outer layer <NUM> has an acrylonitrile content greater than the elastomeric materials of the body-facing layer <NUM> and the middle layer <NUM>. It is believed, without being bound by any particular theory, that fabricating the outer layer <NUM> from high acrylonitrile nitrile material facilitates imparting enhanced chemical resistance properties to the glove <NUM>, as will be described in more detail below. Thus, fabricating only the outer layer <NUM> from high acrylonitrile nitrile material enables the glove <NUM> to have specific chemical resistance at a reduced price point.

The remainder of the elastomeric material used to fabricate the outer layer <NUM> may include polymers such as butadiene, and the like. Polymers with higher levels of acrylonitrile tend to have better resistance to aliphatic oils and solvents, but are also stiffer than polymers that have lower levels of acrylonitrile. Thus, the acrylonitrile content of the elastomeric material is selected to provide a balance of chemical resistance and comfort to the user <NUM>. The elastomeric material is also devoid of natural rubber latex. As such, the outer layer <NUM> contains less than about <NUM> micrograms/gram of protein, or less than about <NUM> micrograms/gram of protein. Thus, the combination and orientation of the body-facing layer <NUM> and the outer layer <NUM> relative to the middle layer <NUM> enables the glove <NUM> to be considered, and labeled as, "latex safe" or "latex free" in accordance with Federal Drug Administration guidelines.

In view of the above criteria, the glove <NUM> may be fabricated from any combination of layers that enables the glove <NUM> to have the desired properties described herein. For example, the outer layer <NUM> may be fabricated from a different material than both the body-facing layer <NUM> and the middle layer <NUM>. In one suitable embodiment, for example, the body-facing layer <NUM> and the middle layer <NUM> may be fabricated from the same material, and the outer layer <NUM> fabricated from a different material than the body-facing layer <NUM> and the middle layer <NUM>. In another suitable embodiment, for example, each of the body-facing layer <NUM>, the middle layer <NUM>, and the outer layer <NUM> are fabricated from different materials. In an alternative embodiment, the outer layer <NUM> may be fabricated from the same material as the body-facing layer <NUM>, and from a different material than the middle layer <NUM>.

In one suitable embodiment, the glove <NUM> is fabricated by dipping a mold into a coagulant bath and then a bath containing elastomeric material in multiple (e.g., at least three) iterative process steps. A coagulant composition in the coagulant bath facilitates adhering the elastomeric material to a hand-shaped former <NUM> (shown in <FIG>), and facilitates adhering adjacent layers <NUM>, <NUM>, and <NUM> of elastomeric material to each other.

Referring to <FIG>, the glove body <NUM> has a combined thickness TC, TP, and TF in respective regions of the glove <NUM>. It should be understood that the dipping process used to fabricate the glove <NUM> may result in variations in the thickness TC of the glove <NUM> in the cuff region <NUM>, the thickness TP of the glove <NUM> in the palm region <NUM>, and thickness TF of the glove <NUM> in the finger region <NUM>. That is, the fingertips <NUM> (shown in <FIG>) of the hand-shaped former <NUM> are typically submerged within a particular bath of elastomeric material first, and thus are in contact with the elastomeric material for a greater period of time than the remainder of the hand-shaped former <NUM>.

As illustrated in <FIG>, the thickness TC of the glove <NUM> in the cuff region <NUM> is defined as a function of a thickness T<NUM> of the body-facing layer <NUM>, a thickness T<NUM> of the middle layer <NUM>, and a thickness T<NUM> of the outer layer <NUM>. As illustrated in <FIG>, the thickness TP of the glove <NUM> in the palm region <NUM> is defined as a function of a thickness T<NUM> of the body-facing layer <NUM>, a thickness T<NUM> of the middle layer <NUM>, and a thickness T<NUM> of the outer layer <NUM>. As illustrated in <FIG>, the thickness TF of the glove <NUM> in the finger region <NUM> is defined as a function of a thickness T<NUM> of the body-facing layer <NUM>, a thickness T<NUM> of the middle layer <NUM>, and a thickness T<NUM> of the outer layer <NUM>.

The thickness TP as measured in the palm region <NUM> of the glove body <NUM> is typically used as the standard for quantifying the feel and tactile sensitivity that may be provided by the glove <NUM>. However, the dipping process should be performed to likewise maintain the thickness TC in the cuff region <NUM> and the thickness TF the finger region <NUM> within predefined tolerances. In one suitable embodiment, the thickness TP is defined within a range between about <NUM> millimeters (mm) and less than <NUM>. The thickness TC is defined within a range between about <NUM> and about <NUM>, defined within a range between about <NUM> and about <NUM>, or defined within a range between about <NUM> and about <NUM>. The thickness TF as measured in the finger region <NUM> is defined within a range between about <NUM> and about <NUM>, defined within a range between about <NUM> and about <NUM>, or defined within a range between about <NUM> and about <NUM>. Thus, the glove <NUM> is fabricated with thicknesses TC, TP, and TF that are selected to provide the user <NUM> with enhanced tactile sensitivity while donning the glove <NUM>.

In the illustrated embodiments, the middle layer <NUM> has a greater average thickness than each of the body-facing layer <NUM> and the outer layer <NUM> in each of the cuff region <NUM>, the finger region <NUM>, and the palm region <NUM>. That is, the average value of thicknesses T<NUM>, T<NUM>, and T<NUM> is greater than the average value of thicknesses T<NUM>, T<NUM>, and T<NUM>, and is greater than the average value of thicknesses T<NUM>, T<NUM>, and T<NUM>. As noted above, the middle layer <NUM> facilitates increasing the flexibility of the glove <NUM> to provide comfort and dexterity to the user <NUM> donning the glove <NUM>. As such, fabricating the middle layer <NUM> to have a greater average thickness than the body-facing layer <NUM> and the outer layer <NUM> in each layer <NUM>, <NUM>, and <NUM> enhances the comfortability of the glove body <NUM> in view of the comparatively stiff materials used to fabricate the body-facing layer <NUM> and the outer layer <NUM>.

In one suitable embodiment, the body-facing layer <NUM> and the outer layer <NUM> may have the same thicknesses. That is, the average value of thicknesses T<NUM>, T<NUM>, and T<NUM> is substantially equal to the average value of thicknesses T<NUM>, T<NUM>, and T<NUM>. In another suitable embodiment, the body-facing layer <NUM> may be thicker than the outer layer <NUM>. That is, the average value of thicknesses T<NUM>, T<NUM>, and T<NUM> is greater than the average value of thicknesses T<NUM>, T<NUM>, and T<NUM>. In another suitable embodiment, the outer layer <NUM> may be thicker than the body-facing layer <NUM>. That is, the average value of thicknesses T<NUM>, T<NUM>, and T<NUM> is greater than the average value of thicknesses T<NUM>, T<NUM>, and T<NUM>.

In the illustrated embodiment, the thicknesses T<NUM>, T<NUM>, and T<NUM> of the body-facing layer <NUM> may be equal to or less than about <NUM>, defined within a range between about <NUM> and about <NUM>, or defined within a range between about <NUM> and about <NUM>. The thicknesses T<NUM>, T<NUM>, and T<NUM> of the middle layer <NUM> may be defined within a range between about <NUM> and about <NUM>, defined within a range between about <NUM> and about <NUM>, or defined within a range between about <NUM> and about <NUM>. The thicknesses T<NUM>, <NUM>, and T<NUM> of the outer layer <NUM> may be equal to or less than about <NUM>, defined within a range between about <NUM> and about <NUM>, or defined within a range between about <NUM> and about <NUM>.

The glove <NUM> fabricated in view of the above description has a variety of physical properties. For example, the glove <NUM> has a tensile strength (before aging) equal to or greater than about <NUM> MPa, or approximately equal to about <NUM> MPa per ASTM D412, ASTM D573, and ASTM D6319. The glove <NUM> has an ultimate elongation (before aging) equal to or greater than about <NUM> percent, or approximately equal to about <NUM> percent per ASTM D412, ASTM D573, and ASTM D6319. The glove <NUM> has a median force at break (before aging) equal to or greater than about <NUM> Newtons, or approximately equal to about <NUM> Newtons per ASTM D412 and EN455-<NUM>:<NUM>. The glove <NUM> has a tensile strength (after aging) equal to or greater than about <NUM> MPa, or approximately equal to about <NUM> MPa per ASTM D412, ASTM D573, and ASTM D6319. The glove <NUM> has an ultimate elongation (after aging) equal to or greater than about <NUM> percent, or approximately equal to about <NUM> percent per ASTM D412, ASTM D573, and ASTM D6319. The glove <NUM> has a median force at break (after aging) equal to or greater than about <NUM> Newtons, or approximately equal to about <NUM> Newtons per ASTM D412 and EN455-<NUM>:<NUM>.

In addition, the glove <NUM> according to the present disclosure provides protection for handling radioactive and/or hazardous materials, such as hazardous chemicals or biological material. It is believed, without being bound by any particular theory, that the presence of high acrylonitrile nitrile material in the outer layer <NUM> enhances the chemical resistance of the glove <NUM> in accordance with the disclosure. When used in combination with the body-facing layer <NUM> and the middle layer <NUM>, the glove <NUM> has specific chemical resistance to certain oils, solvents, and hazardous materials not currently met today with other thin elastomeric articles.

For example, the glove <NUM> has a chemical resistance breakthrough time of greater than about <NUM> minutes for each of Carmustine, Cycophasphomide, Doxorubicin, Eptoposide, Fluorouracil, Paclitaxel, Cisplatin, Dicarbazine, Ifosfamide, Mitoxantrone, Thoitepa, and Vincristine in accordance with ASTM D6978.

The glove <NUM> also has a chemical resistance breakthrough time of greater than about <NUM> minutes, or greater than about <NUM> minutes, for each of methanol, acetone, acetonitrile, dichloromethane, carbon disulphide, toluene, diethylamine, tetrahydrofuran, ethyl acetate, n-haptane, <NUM> percent sodium hydroxide, <NUM> percent sulphuric acid, <NUM> percent nitric acid, <NUM> percent acetic acid, <NUM> percent ammonium hydroxide, <NUM> percent hydrogen peroxide, <NUM> percent hydrofluoric acid, and <NUM> percent formaldehyde in accordance with EN <NUM>-<NUM>. That is, the glove <NUM> has a chemical performance of at least Class <NUM> against all <NUM> chemicals listed in EN ISO <NUM>-<NUM>.

The glove <NUM> also has a chemical resistance breakthrough time of greater than about <NUM> minutes for each of isopropyl alcohol and dimethyl sulfoxide, and has a chemical resistance breakthrough time of greater than about <NUM> minutes for hydrochloric acid per EN <NUM>-<NUM>.

The glove <NUM> also complies with the requirements for the registration of new products with the Korean Occupation Safety & Health Administration (KOSHA). That is, the glove <NUM> has a chemical resistance breakthrough time of greater than about <NUM> minutes for at least three chemicals in the following list of chemicals: methanol, acetone, acetonitrile, dichloromethane, carbon disulphide, toluene, diethylamine, tetrahydrofuran, ethyl acetate, n-hexane, <NUM> percent sodium hydroxide, and <NUM> percent sulphuric acid. That is, the glove <NUM> has a chemical performance of at least Class <NUM> against three of the chemicals listed above.

In addition, the glove <NUM> achieves at least Class <NUM> performance for at least one of the testing items listed in Table <NUM>, in accordance with KOSHA requirements.

In addition, the glove <NUM> is food contact safe in accordance with BfR Regulations (European Union) and in accordance with US FDA Cfr <NUM> (North America and Canada), is safe to use with disinfectants, conforms to ESD <NUM> for surface resistivity, and conforms to ISO <NUM> for viral penetration.

In the illustrated embodiment, the glove <NUM> is cleanroom approved. For example, the glove <NUM> has a particle count less than about <NUM> per square centimeter for particles <NUM> microns or larger per IEST-RP-CC005. In addition, the glove <NUM> has a calcium ion concentration equal to or less than about <NUM> micrograms/gram, a chloride ion concentration equal to or less than about <NUM> micrograms/gram, a magnesium ion concentration equal to or less than about <NUM> micrograms/gram, a nitrate ion concentration equal to or less than about <NUM> micrograms/gram, a potassium ion concentration equal to or less than about <NUM> micrograms/gram, a sodium ion concentration equal to or less than about <NUM> micrograms/gram, a sulfate ion concentration equal to or less than about <NUM> micrograms/gram, a zinc ion concentration equal to or less than about <NUM> micrograms/gram, a ammonium ion concentration equal to or less than about <NUM> micrograms/gram per IEST-RPCC005.

In some embodiments, the wet and dry gripping ability of the gloves <NUM> are improved via texturing, for example, as will be described in more detail below. The gripping ability of the gloves <NUM> is measured using grip tests such as the SATRA TM437 methodology, the SATRA TM438 methodology, and the SATRA <NUM> methodology. SATRA TM437 covers finger and thumb 'pinch grip', and SATRA TM438 provides a method of testing 'whole hand grip' (thumb, four fingers and palm).

The SATRA TM437 'pinch-grip test' requires a subject wearing a glove to grip an instrumented, vertically-suspended flat metal bar, and to pull the bar downwards to lift a counterbalanced weight by a set distance. The grip is then relaxed until slippage of the bar against the glove surface is detected, when the wearer must increase the grip to prevent further slippage. The bar is then gently raised to its original, unloaded position. Throughout the test cycle, the grip forces are recorded by means of an electronic load cell within the bar. The wearer's comments on the ease of action and the effectiveness of the grip (which will include a subjective opinion of the security between the glove lining and the wearer's skin, as well as that between the glove outer and the test bar) are also recorded. The results generated are both objective (force data from the load cell within the grip bar) and subjective (user comments on glove performance).

The SATRA TM438 'whole hand grip' test requires the test subject to grip a cylinder, and to pull the cylinder downwards to lift a large counterbalanced weight to a set distance. The grip is then held for a set time before returning the cylinder to the original, unloaded position. If any slippage occurs, the subjects are required, if possible, to maintain grip by applying a higher force. This test gives an indication of how the grip surface across the whole glove performs under realistic working conditions. Again, the results generated are both objective (force data from the load cell within the grip cylinder) and subjective (user comments on glove performance).

The article of the present invention may be formed using a variety of processes including dipping, for example spraying, tumbling, drying, and curing. As will be described in more detail below, each layer <NUM>, <NUM>, and <NUM> is formed in a dip process in a series of process steps. For example, referring to <FIG>, a series of glove molds or hand-shaped formers <NUM> may be used to form the glove <NUM> (shown in <FIG>) of the present disclosure. Referring to <FIG>, the outer layer <NUM> is initially formed on the hand-shaped former <NUM> such that the outer layer <NUM> is in contact with the hand-shaped former <NUM>. The middle layer <NUM> and then the body-facing layer <NUM> are formed on the hand-shaped former <NUM> over the outer layer <NUM>. The glove <NUM> is inverted when stripped from the hand-shaped former <NUM> such that the body-facing layer <NUM> defines an interior of the glove <NUM> for receiving the hand and arm of the user <NUM>, and such that the outer layer <NUM> is exposed to an ambient environment.

The hand-shaped formers <NUM> shown in <FIG> are illustrated on a pallet <NUM> used in a batch processing operation, but it should be understood that the process of the present disclosure may also be utilized in a continuous operation.

A hand-shaped former <NUM> may be generally recognized as a contoured mold having a textured or smooth surface which may accept a series of coatings and then release the formed glove <NUM>. Example coating materials include, but are not limited to, calcium stearate, poly vinyl chloride, and poly (methyl methacrylate). The hand-shaped former <NUM> may be fabricated from any material that enables the process of the present disclosure to function as described herein. For example, the surface of the hand-shaped former <NUM> may be formed of ceramic, porcelain, glass, metal, or certain fluorocarbons.

Texturing the hand-shaped former <NUM> facilitates improving the wet and dry gripping ability of the gloves <NUM> formed thereon. The texturing may be achieved by embossing, divoting, flexible casting, and the like. In one suitable embodiment, the hand-shaped former <NUM> is textured to have a patterned area <NUM> on select areas of the mold, such as on the fingertips <NUM> of the hand-shaped former <NUM>. Alternatively, the patterned area <NUM> may be provided on other areas of the mold to provide texturing over the whole, or part, of other regions of the glove, such as the finger region <NUM> and the palm region <NUM>. As will be described in more detail below, the glove <NUM> formed on each hand-shaped former <NUM> is stripped and inverted to remove the glove <NUM> from the hand-shaped former <NUM>. Thus, as illustrated in <FIG>, texturing the hand-shaped former <NUM> facilitates defining a corresponding patterned area <NUM> on the former-facing layer (i.e., the outer layer <NUM>) of the glove <NUM> during fabrication.

The patterned area <NUM> may include any suitable texturing that facilitates improving the grip of the glove <NUM>. The texturing may be defined by any suitable geometric shapes, non-geometric shapes, or combinations thereof. For example, as illustrated in FIG. <NUM>, the patterned area <NUM> is defined by a plurality of shapes <NUM> having a diamond configuration formed in the outer layer <NUM> of the glove <NUM>. Adjacent shapes <NUM> are spaced from each other by a distance D, and the distance D may be any suitable distance for improving the grip of the glove <NUM>. The spacing between adjacent shapes <NUM> is illustrated as being substantially equidistant. However, the shapes <NUM> may be spaced from each other by irregular distances D as well. In addition, the shapes <NUM> may be formed as indents recessed relative to a surface <NUM> of the outer layer <NUM>, or as ridges that are raised relative to the surface <NUM> of the outer layer <NUM>.

Turning to <FIG>, the hand-shaped former <NUM> is fabricated from material such that at least a surface <NUM> of the hand-shaped former <NUM> is colored to provide a contrasting visual appearance with the layers of elastomeric material to be formed thereon. Typically, hand-shaped formers <NUM> commonly fabricated from ceramic material have a substantially white visual appearance. When subsequent layers of elastomeric material having the same color as the hand-shaped former <NUM> are formed thereon, it becomes increasingly difficult to visually inspect the glove <NUM> and/or to readily determine if the glove <NUM> is defective. In the illustrated embodiment, the surface <NUM> of the hand-shaped former <NUM> is a first color <NUM>, as illustrated by a first pattern, that provides a contrasting visual appearance with layers of the glove <NUM> for rapid on-line inspection of the gloves <NUM> for defects.

In addition, each layer <NUM>, <NUM>, and <NUM> of elastomeric material formed on the hand-shaped former <NUM> may likewise be colored to provide a contrasting visual appearance with the hand-shaped former <NUM>, and/or with the other layers included in the glove body <NUM>. In the illustrated embodiment, the body-facing layer <NUM> is a second color <NUM>, the middle layer <NUM> is a third color <NUM>, and the outer layer <NUM> is a fourth color <NUM>, each illustrated by contrasting patterns in FIG. In one suitable embodiment, the first color <NUM>, the second color <NUM>, the third color <NUM>, and the fourth color <NUM> are each different contrasting colors. Alternatively, the second color <NUM>, the third color <NUM>, and the fourth color <NUM> of the layers <NUM>, <NUM>, and <NUM> are the same color, which is different than the first color <NUM> of the hand-shaped former <NUM>. Further alternatively, the second color <NUM> and the fourth color <NUM> are the same color, and the third color <NUM> is different than the second color <NUM> and the fourth color <NUM>. As such, the contrasting colors facilitate providing a visual indication of a potential defect on the manufacturing line, or of wear and tear during use of the glove <NUM>.

Turning to <FIG>, an exemplary dipping process for forming the glove <NUM> is described herein, though other processes may be employed to form various articles having different shapes and characteristics.

In the illustrated embodiment, the hand-shaped former <NUM> (shown in <FIG>) is cleaned <NUM> prior to formation of a glove on the hand-shaped former <NUM>. The cleaning process generally includes an optional water pre-rinse followed by an acid wash. After the acid wash, the hand-shaped former <NUM> is mechanically scrubbed with a brush, for example, and then rinsed with water and submerged in a heated caustic solution prior to a final rinse. After the optional cleaning process, the hand-shaped former <NUM> is dried <NUM> in preparation for forming a glove on the hand-shaped former <NUM> through a series of dipping and drying steps.

For example, in one suitable embodiment, after the cleaning <NUM>, the hand-shaped former <NUM> is dipped into a powder-free coagulant composition in a first coagulant dip tank <NUM>. In general, the coagulant composition causes a base polymer, which will form a substrate body of the glove <NUM>, to coagulate and polymerize on the hand-shaped former <NUM>. Coagulants that may be used in the present disclosure may include a solution of a coagulant salt such as a metal salt. Examples of coagulants may include but are not limited to water soluble salts of calcium, zinc, aluminum, and the like. For example, in one embodiment, calcium nitrate in water or alcohol may be used in the coagulant composition. In some embodiments, calcium nitrate may be present in the solution in an amount of up to about <NUM>% by weight although a greater or lesser amount may also be used. Optionally, the coagulant composition may also contain additives such as surfactants.

After being immersed in the coagulant composition, the hand-shaped former <NUM> is withdrawn from the first coagulant dip tank <NUM> and the coagulant present on the surface of the former is allowed to dry in a first coagulant drying step <NUM>. For many applications, the coagulant may be air dried for a time of from about one minute to about two minutes. Once dried, a residual coating of the coagulant remains on the hand-shaped former <NUM>.

If desired, the coagulant composition may optionally contain certain additives. For example, the coagulant composition may contain various additives which may improve the tactile characteristics of a surface of the glove. Alternatively, the coagulant composition may contain certain release aids which, when combined with the processes of the present invention, may further improve the stripping ability of the glove <NUM> from the hand-shaped former <NUM>. In any case, coagulant composition additives should not hinder the processes of the present invention.

After the first coagulant drying step <NUM> is complete, the hand-shaped former <NUM> is dipped into a first elastomer dip tank <NUM> containing a first elastomeric material. The first elastomeric material is a composition that coincides with the material for forming the outer layer <NUM>, as described above. The first elastomeric material may also contain various additives such as pH adjustors, stabilizers, and the like as are generally known in the art. Upon contact of the first elastomeric material with the coagulant composition, the coagulant may cause some of the first elastomeric material to become locally unstable and coagulate on the surface of the hand-shaped former <NUM>. In many applications, the coagulant itself does not form a separate layer of the final glove, but rather becomes a part of the outer layer <NUM> of the glove <NUM>. Any additives in the coagulant composition may, depending upon what they are, remain between the hand-shaped former <NUM> and the outer layer <NUM>, or alternatively may be incorporated into the outer layer <NUM>. After the desired amount of time, the hand-shaped former <NUM> is withdrawn from the first elastomer dip tank <NUM>, and the coagulated layer of elastomeric material is allowed to coalesce fully on the former.

The amount of time the hand-shaped former <NUM> is immersed (commonly termed as dwell time) in the first elastomeric material determines the thickness of the outer layer <NUM>. Increasing the dwell time of the hand-shaped former <NUM> in the first elastomeric material causes the thickness of the outer layer <NUM> (shown in <FIG>) to increase. The total thickness of the glove body <NUM> may depend on other parameters as well, including, for example, the solids content of the latex emulsion and the additive content of the latex emulsion and/or the coagulant composition. In the illustrated embodiment, the dwell time of the hand-shaped former <NUM> within the first elastomer dip tank <NUM> is selected to define the thickness T<NUM>, T<NUM>, and T<NUM> (shown in <FIG>) of the outer layer <NUM> in accordance with the parameters noted above.

Once the hand-shaped former <NUM> is removed from the first elastomeric material, the outer layer <NUM> formed thereon may be, optionally, at least partially cured <NUM> in preparation for the hand-shaped former <NUM> receiving subsequent layers, such as the middle layer <NUM> and the body-facing layer <NUM> (both shown in <FIG>), thereon. The process steps for forming the middle layer <NUM> and the body-facing layer <NUM> on the hand-shaped former <NUM> is generally the same as the process steps for forming the outer layer <NUM> thereon. For example, after the optional curing <NUM>, the hand-shaped former <NUM> with the outer layer <NUM> formed thereon is dipped into a coagulant composition in a second coagulant dip tank <NUM>, the coagulant composition is allowed to dry in a second coagulant drying step <NUM>, and the hand-shaped former <NUM> is dipped into a second elastomer dip tank <NUM> containing a second elastomeric material. The second elastomeric material is a composition that coincides with the material for forming the middle layer <NUM>, as described above.

The hand-shaped former <NUM> is then removed from the second elastomeric material, and the middle layer <NUM> formed thereon may be, optionally, at least partially cured <NUM>. The hand-shaped former <NUM> with the outer layer <NUM> and the middle layer <NUM> formed thereon is dipped into a coagulant composition in a third coagulant dip tank <NUM>, the coagulant composition is allowed to dry in a third coagulant drying step <NUM>, and the hand-shaped former <NUM> is dipped into a third elastomer dip tank <NUM> containing a third elastomeric material. The third elastomeric material is a composition that coincides with the material for forming the body-facing layer <NUM>, as described above. Specific process details, examples, and additive options, for example, described in the context of formation of the outer layer <NUM> on the hand-shaped former <NUM> are described in detail above. However, it should be understood that the process details, examples, and additive options are also applicable in the formation of the middle layer <NUM> and the body-facing layer <NUM> on the hand-shaped former <NUM>.

Once removed from the third elastomer dip tank <NUM>, the glove <NUM> is beaded <NUM> to facilitate defining the cuff region <NUM> of the glove, and to facilitate stripping of the glove <NUM> from the hand-shaped former <NUM>. The glove <NUM> may then be further processed, as desired. For example, various pre-cure processing techniques are generally known in the art. For example, the uncured body-facing layer <NUM> may be leached <NUM> with flowing hot water. The leaching process may extract various emulsion constituents, such as salts and water, for example, from the coalesced elastomeric material. This may cause the glove body <NUM> to shrink somewhat on the hand-shaped former <NUM> and remove impurities from the coalesced emulsion.

The outer layer <NUM>, middle layer <NUM>, and body-facing layer <NUM> may then be cured <NUM>, or vulcanized, to form the glove body <NUM>. In general, the elastomeric materials are cured by high temperature reaction with a vulcanizing agent, such as sulfur, to cause cross-linking of the polymer chains. Curing <NUM> may generally take place at temperatures of between about <NUM>,<NUM>° C (<NUM>° F) and about <NUM> (<NUM>° F). In addition to curing the elastomeric materials, the high temperature process may cause the evaporation of any volatile components remaining on the hand-shaped former <NUM>, including any water remaining in the emulsion. Therefore, the curing process <NUM> may cause shrinkage in the glove body <NUM> and the thickness of the cured elastomeric layers may generally be less than the thickness of the emulsions coalesced on the hand-shaped former <NUM>.

After the elastomeric materials have been cured, additional processing steps may be performed. For example, the surface of the glove may be chemically treated following the curing, such as in a halogenation process <NUM>. Halogenation processes <NUM> such as chlorination are known in the art and have been used for various purposes, such as for reducing the tackiness on the surface of a nitrile rubber article. In one embodiment, a halogenation process <NUM> includes injecting a halogen gas, such as chlorine gas, for example, into water and then dipping the hand-shaped former <NUM> into the halogenated water. Other known methods of chlorinating the glove can alternatively be used, however.

For example, in one suitable embodiment, the halogenation process <NUM> includes contacting the glove <NUM> with bromine gas rather than chlorine gas. Use of the bromine gas in the halogenation process <NUM> facilitates reducing discoloration of the glove <NUM>, and is potentially safer to process and utilize in the glove manufacturing process.

After the glove is cured and any post-cure processing steps have been completed, the glove body <NUM> on the hand-shaped former is rinsed <NUM> with water, such as in a water bath, and then dried <NUM> prior to stripping <NUM> the article from the hand-shaped former <NUM>. For most applications, the gloves <NUM> may be dried <NUM> while still on the hand-shaped former <NUM> prior to stripping. Alternatively, however, in some applications, it may also be possible to strip the glove body <NUM> from the hand-shaped formers <NUM> while wet and then dry the articles later.

When drying <NUM> the articles prior to stripping <NUM>, the gloves <NUM> while still on the formers may be dried by applying heat to the gloves <NUM>. For instance, the gloves <NUM> while on the hand-shaped formers <NUM> may be contacted with hot air, such as in a convective oven. For example, in one embodiment, the hand-shaped formers <NUM> may be transferred from the liquid bath to an oven to be dried.

In the oven, convective air at a high temperature may dry the film and remove any residual moisture. For example, convective air at a temperature of between about <NUM>° C (<NUM>° F)and about <NUM>° C (<NUM>° F) may be used to dry the hand-shaped formers <NUM>. In this temperature range, the drying process may be very fast, for example, the gloves <NUM> may be dried in the oven for about <NUM> minutes. In one embodiment, the gloves <NUM> may be dried in the oven in about one minute. In another embodiment, the gloves <NUM> may be dried in the oven for less than about one minute.

In an embodiment wherein the gloves <NUM> are dried while still on the hand-shaped formers <NUM>, the gloves <NUM> may optionally be cooled after the residual moisture is removed and then stripped <NUM> from the hand-shaped formers <NUM>. The gloves <NUM> may be cooled either actively (e.g., subjecting the formers to a cool air stream) or passively, or a combination of both as by merely removal from the oven and cooled for period in ambient air. In one embodiment, the gloves <NUM> may be cooled to a temperature of less than about <NUM>° C (<NUM>° F). Once dried and cooled, the gloves <NUM> are stripped and packaged <NUM> from the hand-shaped formers <NUM>. The hand-shaped formers <NUM> may then be re-used to fabricate additional gloves <NUM>.

Referring again to <FIG>, in the illustrated embodiment, the hand-shaped formers <NUM> are each outfitted with a radio-frequency identification (RFID) system <NUM>. The RFID system <NUM> facilitates monitoring the steps and/or parameters of the process for fabricating the glove <NUM>, such as those illustrated in <FIG>. For example, the RFID system <NUM> counts of a number of cycles undergone by each hand-shaped former <NUM> upon initial engagement of the former cleaning step <NUM>. Counting the number of cycles facilitates tracking the usage of each hand-shaped former <NUM> to facilitate inspection and/or refurbishment of the hand-shaped former <NUM>. The RFID system <NUM> may also monitor the pH on the surface <NUM> (shown in <FIG>) of the hand-shaped former <NUM> in one or more of the illustrated process steps, such as the cleaning step <NUM> and the elastomer dipping steps <NUM>, <NUM>, and <NUM>. Monitoring the pH on the surface <NUM> ensures there is no material buildup on the hand-shaped former <NUM> in the cleaning step <NUM>, and ensures there is low webbing and no bubble formation in the dipping steps <NUM>, <NUM>, and <NUM>.

The RFID system <NUM> may also monitor the temperature on the surface <NUM> of the hand-shaped former <NUM> in one or more of the illustrated process steps, such as the drying step <NUM>, the coagulating drying steps <NUM>, <NUM>, and <NUM>, and the curing steps <NUM>, <NUM>, and <NUM>. Monitoring the temperature on the surface <NUM> facilitates determining whether the surface <NUM> is dry as a result of each cleaning step. Monitoring the temperature also ensures that the hand-shaped former <NUM> has spent enough time at a predetermined curing temperature to adequately cure the layers <NUM>, <NUM>, and <NUM> on the hand-shaped former <NUM>. In the beading step <NUM>, the RFID system <NUM> may also measure a length from a bead position to a fingertip of the middle finger on the glove <NUM> to verify the glove length. The RFID system <NUM> may also measure the bead thickness on the hand-shaped former <NUM>.

The terms "comprising," "including", and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

Claim 1:
An elastomeric glove (<NUM>) comprising:
a body-facing layer (<NUM>) of a first elastomeric material;
a middle layer (<NUM>) of a second elastomeric material; and
an outer layer (<NUM>) of a third elastomeric material different than the second elastomeric material,
wherein the third elastomeric material has an acrylonitrile content greater than both the first elastomeric material and the second elastomeric material,
wherein the elastomeric glove comprises a cuff region (<NUM>), a finger region (<NUM>), and a palm region (<NUM>),
characterized in that,
the body-facing (<NUM>), middle (<NUM>), and outer layers (<NUM>) of material have a combined thickness of less than <NUM> millimeters in the palm region (<NUM>) of the elastomeric glove (<NUM>), and
wherein the third elastomeric material has an acrylonitrile content of between <NUM> and <NUM> percent by weight.