Static Dissipative Protective Gloves

Abstract

The present invention relates to a static dissipative protective glove and a corresponding method for manufacturing the protective glove, which comprises a polymer foam layer, the volume resistivity of which is reduced to a desired value by adding carbon fibers.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates to static dissipative protective gloves and corresponding methods of manufacturing protective gloves. [Background technology]

[0002] Static dissipative gloves have a particular role in the field of protective gloves, for example in explosive workplaces where reliable dissipation of static electricity is required.

[0003] It is known to incorporate additives into polymeric coatings on protective gloves to favorably affect various properties such as abrasion resistance, grip, flexibility, etc.

[0004] It is also known to incorporate conductive additives into coatings to reduce their surface and / or volume resistivity. For example, a dispersion of conductive carbon black is added to the polymeric coating compound. Due to the spherical structure of the carbon black particles contained therein, a large amount of them must be used to achieve the desired electrical conductivity.

[0005] Alternatively, dispersions containing elongated particles such as carbon nanotubes can be used, and because of their anisotropic properties, smaller amounts are effective. The drawback of using carbon nanotubes is that a highly diluted dispersion must be added to the polymer compound to prevent the carbon nanotubes from agglomerating. Dispersions containing less than 5% carbon nanotubes are common. This necessitates the use of larger amounts of dispersion, which is only possible by reducing the proportion of polymer in the polymer compound. However, reducing the proportion of polymer can result in undesirable changes in properties such as the pH or viscosity of the polymer compound.

[0006] In particular, protective gloves coated with foamed polymers present problems due to the increased volume resistivity caused by insulating gas pockets. Furthermore, many conventional conductive additives have the drawback of reduced foaming stability as the polymer content decreases. This means that the foam becomes coarse and / or dense within a relatively short period of time, meaning that the foam tends to collapse more quickly. As a result, stable product quality cannot be ensured. Summary of the Invention [Problem to be solved by the invention]

[0007] It is an object of the present invention to provide an electrostatic dissipative protective glove having a polymer foam layer with improved polymer foaming stability. It is also an object of the present invention to provide a method for manufacturing the protective glove according to the present invention.

[0008] The object of the present invention is to provide a protective glove according to claim 1. In the bag This is achieved. Advantageous embodiments are the subject matter of the dependent claims. [Means for solving the problem]

[0009] The protective glove of the present invention is comprised of at least two layers, the first of which is a polymer foam layer. The polymer foam layer contains carbon fibers, which reduce volume resistivity. Carbon fibers are particularly suited to this application because their elongated shape allows fewer carbon fibers to form conductive paths within the polymer matrix than spherical particles. Therefore, a significantly smaller number of carbon fibers can be added to the latex compound to achieve the desired volume resistivity. Furthermore, unlike carbon nanotubes, carbon fibers are added directly to the latex compound without pre-dissolving them in a dispersion. Therefore, the additive has little effect on the properties of the latex compound, such as polymer content, viscosity, pH value, and ultimately workability. Furthermore, the addition of carbon fibers has little effect on the mechanical properties of the finished glove. Furthermore, it has been surprisingly discovered that carbon fibers provide higher foam stability compared to conventional conductive additives. That is, foaming, and therefore product quality, remains stable for a longer period of time compared to compounds without carbon fibers.

[0010] The carbon fiber is preferably 10 μ m to 1000 μ m length, particularly preferably 50 μ m to 250 μ The carbon fibers are crushed carbon fibers having a length of 1000 m. To obtain this, for example, the fibers can be cut or crushed.

[0011] According to the invention, the diameter of the carbon fibers is significantly smaller than their length, preferably 2 μ m to 25 μ m, particularly preferably 3 μ m to 9 μ m. Also, fiber bundles consisting of several carbon fibers are possible, and the diameter of the fiber bundle is longer, for example, 100 μ It will also be obvious to one skilled in the art to use other conductive synthetic or natural fibers available in a wide variety of shapes, for example, metallized or coated with conductive carbon black.

[0012] The foam layer may be composed of a synthetic or natural polymer. Preferably, the polymer foam layer comprises nitrile, chloroprene, isoprene, natural latex, polyurethane rubber, or a mixture of one or more of these components. Preferably, the foamable polymer coating may contain, in addition to the carbon fiber according to the present invention, other additives such as crosslinking aids, thickeners, or color pigments. Particularly preferably, the polymer foam layer is substantially composed of nitrile rubber.

[0013] According to the present invention, the polymer foam layer is foamed, i.e., contains gas pockets. This may be a closed-pore foam, an open-pore foam, or a mixture of both types. The pockets may contain air or another gas or gas mixture, which may be introduced in various ways. Those skilled in the art will recognize, for example, the use of a foam mixer or chemical foaming as common methods. [Brief explanation of the drawings]

[0014]

Figure 1

[0015] In a preferred embodiment of the protective glove, the second layer of the glove is comprised of a textile substrate. This type of knitted glove can provide, for example, increased comfort or cut protection. The textile substrate contacts the user's skin, while the polymer foam layer forms the outer layer of the glove.

[0016] In another preferred embodiment of the protective glove, the conductive yarn is incorporated into the textile substrate. The conductive yarn provides dissipative properties to the textile substrate. Suitable materials for the conductive yarn may be, for example, metallic materials (e.g., steel, copper, or silver), may include carbon fiber, or may be otherwise metallized or conductively modified yarn.

[0017] In another embodiment, the protective glove includes a second, non-foamed polymer layer in addition to the foam layer according to the present invention. Thus, by using the non-foamed polymer layer as a substrate for the foam layer according to the present invention, a nonwoven glove can be provided. This is suitable, for example, for chemical protection gloves. The non-foamed polymer layer in this embodiment can be conductively modified as needed.

[0018] Alternatively, the protective glove may be constructed from a multi-layer system including a textile substrate, one or more non-foamed polymer layers, and a foam layer according to the present invention. All additional layers may be conductively modified. In a corresponding embodiment, the protective glove may include, for example, a non-foamed polymer layer between the textile substrate according to the present invention and the polymer foam layer. As a result, the present invention allows for the waterproofing properties of the non-foamed layer and the dissipative properties of the polymer layer to be combined with the comfortable wearability of the textile.

[0019] Furthermore, combinations of other textile or polymer layers, whether identical or different, are contemplated. It is also clear that the various layers may cover the glove to different extents. For example, knitted mechanical protection gloves are coated only in the finger and palm areas. In contrast, chemical protection gloves are fully coated, i.e., including the cuff, but often have an additional grip layer that covers only the finger and palm areas.

[0020] In another preferred embodiment, the protective glove according to the present invention has a volume resistivity of 10 8 This satisfies the requirements for protective gloves of DIN EN 16350. According to the present invention, this volume resistivity can be achieved by setting the solids content of carbon fibers in the latex compound to less than 4 wt.%.

[0021] The method according to the present invention for producing a protective glove according to the present invention comprises the following steps for a nitrile rubber foam layer: First, a latex compound is provided. Preferably, the latex compound is a latex compound containing nitrile rubber. Carbon fibers are added to the latex compound. The carbon fibers do not need to be in suspension and can be added directly to the latex compound without undesired agglomeration occurring. In the next step, the compound is foamed. Foaming is carried out by mechanically incorporating a defined amount of air into the latex compound, preferably in a foam mixer. The added carbon fibers improve foam stability. The foamed mass is then pumped to a dip tank.

[0022] In a preferred method for manufacturing nonwoven protective gloves, a hand-shaped former is prepared and dipped into a foamed latex compound containing carbon fiber. The former may be treated with a coagulating saline solution prior to dipping. The glove is then dried and removed from the former.

[0023] A preferred method for manufacturing knitted protective gloves involves the following steps: First, a hand-shaped dip former is prepared and preheated. The dip former is preferably made of aluminum or a ceramic material. A knitted glove made of a textile substrate is placed on the preheated dip former. Preferably, the knitted glove is interspersed with conductive threads. Particularly preferably, the knitted glove is made from a single piece of fabric, i.e., a so-called "seamless" glove. In the next step, the dip former with the knitted glove is immersed in a coagulating saline solution. The coagulating agent prevents rubber bubbles from completely penetrating the textile substrate before the latex compound begins to coagulate. In the next step, the dip former is removed from the saline solution and dried. Next, the dip former with the dried knitted glove is immersed in a foam latex compound containing carbon fiber. The dip former is then removed from the latex compound and pre-dried. Following this, the former with the newly coated textile substrate is immersed in a water bath to remove excess coagulant. In the next step, the former with the coated textile substrate is dried, preferably at a temperature of 100°C to 130°C. In the final step, the finished protective glove is removed from the former.

[0024] In a preferred method for manufacturing multi-layer knitted protective gloves, knitted gloves on a former are first dipped in a coagulating saline solution, dried, and then dipped in a non-foaming coating compound. The coated gloves are then dipped in a foaming latex compound containing carbon fiber. The former is then removed from the latex compound, pre-dried, washed, dried, and finally the gloves are stripped from the former.

[0025] The solid content of carbon fiber in the latex compound is preferably less than 4.0 wt.%, and particularly preferably 4.0 wt.% to 1.0 wt.%. Such a low solid content has almost no effect on the mechanical properties of foaming, and has the advantage of increasing foaming stability. [Explanation of symbols]

[0026] 1 Nitrile rubber foam layer 2. Inside

Claims

1. A protective glove consisting of at least two layers, a first layer and a second layer, wherein the first layer is a polymer foam layer, the polymer foam layer being on an outer layer of the protective glove; The polymer foam layer contains carbon fibers having a diameter of 3 μm to 9 μm, and the polymer foam layer contains a latex compound to which the carbon fibers are added to produce a predetermined volume resistance of the protective glove, and the volume resistance of the protective glove measured in accordance with DIN EN 16350 is 10 ８ and the solid content of the carbon fiber in the latex compound is 4.0 wt. % to 1.0 wt. %.

2. 10. The protective glove of claim 1, wherein the polymer foam layer comprises nitrile, chloroprene, isoprene, natural latex, or polyurethane rubber, or a mixture thereof.

3. 3. The protective glove of claim 1, wherein the polymer foam layer substantially comprises nitrile rubber.

4. 4. The protective glove according to claim 1, wherein the second layer is formed by a textile substrate.

5. The protective glove according to claim 4, wherein conductive yarn is blended into the woven fabric substrate.

6. 4. The protective glove according to claim 1, wherein the second layer is formed by a non-foamed polymer layer.

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