Nitrile coated gloves and method of producing the gloves

Abstract

The present invention relates to a nitrile coated glove, and a method of producing same. The glove comprising: a glove liner; a first layer of a nitrile compound which has been roll coated onto the liner, the first layer being formed from a coating having a first viscosity; at least one second layer of a nitrile compound coated onto the first layer, the second and any subsequent layers having a lower viscosity of nitrile compound coating than that of the first layer; and one or more friction areas formed by a plurality of nitrile granules spread on the second layer.

Description

[0001] NITRILE COATED GLOVES AND METHOD OF PRODUCING THE GLOVES

[0002] FIELD OF TECHNOLOGY

[0003] The present invention relates generally to the field of glove and its manufacturing process, more particularly, to gloves having at least a layer of nitrile coating and its manufacturing process.

[0004] BACKGROUND OF THE INVENTION

[0005] Nitrile gloves are gaining popularity as compared to natural rubber gloves due to reduced risk of latex allergies. Further, nitrile gloves are relatively strong and resistance to most chemicals. Additionally, nitrile gloves are well-accepted in countries with strict regulations for use in dealing with fatty foods, such as, fish, chicken, or red meat. There are gloves with liners coated with nitrile compounds to widen the application. For example, Canadian Patent No. CA 2639874 C and European Patent No. EP 3369332 Bl. Further, there are nitrile gloves incorporated with textures or features such as those as disclosed in LTnited States Patent No. 7356852, LTnited States Patent No. 10349690 B2, United States Patent Application No. US 2018125132 Al and Chinese Patent No. 108433220 B, mainly to enhance gripping. Particularly, United States Patent No. 7356852 and United States Patent Application No. US 2018125132 Al focused on the shapes and dimensions of the gripping features, while United States Patent No. 10349690 B2 is focused on the combination of different polymeric compositions adapted to enhance grip, such as a coating of nitrilebutadiene composition and raised features comprising polyurethane. Further, CN 108433220 B provided gripping features made of nitrile granules. Due to vast possibilities and also a high demand of nitrile-coated gloves, there is a need for an environmentally friendly method to manufacture them without compromising the quality. The present invention provides a manufacturing process of nitrile-coated gloves aimed to use less chemicals and with simplified steps.

[0006] SUMMARY OF THE INVENTION

[0007] One aspect of the present invention is to provide a glove which is soft to touch. Particularly, a roll-coating step is involved in manufacturing the glove whereby the penetration of the nitrile compound on the liner can be controlled hence preventing over-penetration of the nitrile compound that causes formation of undesirable hard layer on the liner.

[0008] Another aspect of the present invention is to provide a glove comprising friction areas formed by nitrile granules. In one embodiment, the nitrile granules are randomly distributed on the gloves. In a preferred embodiment, the granules are concentrated on a certain area of the gloves, as desired. For instance, the nitrile granules are distributed in the palm area and / or the finger areas of the gloves.

[0009] Another aspect of the present invention is to provide a glove comprising a back-hand area configured with a protective feature derived from thermoplastic rubber (TPR) and / or thermoplastic polyurethane (TPU). A back-hand area refers to an area of the glove which covers the dorsal side of a hand. Preferably, the TPR and / or TPU protective feature is configured in strips and / or patches with foldable ridges to maintain a best possible flexibility of the gloves when in use.

[0010] Another aspect of the present invention is to provide a method to prevent over-penetration of nitrile compound on a fabric liner, such as a cotton liner. The method involves a step of roll-coating of nitrile compound on the liner so as to prevent over-penetration problem commonly caused by dip-coating. Another aspect of the present invention is to provide an environmentally friendly method of producing nitrile-coated gloves. Advantageously, the method omits the use of alcohol or coagulants commonly used in pre-treatment of liners.

[0011] At least one of the preceding aspects is met, in whole or in part, by the present invention, in which one of the embodiments of the present invention is a nitrile coated glove comprising: a glove liner; a first layer of a nitrile compound which has been roll coated onto the liner, the first layer being formed from a coating having a first viscosity; at least one second layer of a nitrile compound coated onto the first layer, the second and any subsequent layers having a lower viscosity of nitrile compound coating than that of the first layer; and one or more friction areas formed by a plurality of nitrile granules spread on the second layer.

[0012] In another embodiment, the nitrile coated glove further comprising thermoplastic rubber (TPR) and / or thermoplastic polyurethane (TPU) configured at the back-hand area of the gloves.

[0013] In one embodiment, the nitrile compound of the first, second or any subsequent layers comprises at least one of acrylonitrile butadiene rubber, chloroprene, polyisoprene, or any combination thereof.

[0014] Preferably, the highest viscosity of the second and any subsequent layers is substantially lower than the lowest viscosity of the first layer. In a preferred embodiment, the first viscosity ranges from 800 to 1200 mPa.s and the lower second viscosity ranges from 200 to 600 mPa.s. In one embodiment, the first viscosity is suitable for coating of the first nitrile compound onto the liner. In another embodiment, the second viscosity is suitable for coating of the second nitrile compound onto the first nitrile layer. Viscosity is relevant to control thickness of each layer. Hence, a suitable viscosity is able to ensure evenness in the coating thereby preventing dripping. Preferably, the liner is made of at least one of cotton, terry cotton, rayon, fleece, or any combination thereof. More preferably, the liner is cut-resistant by incorporating high performance polyethylene (HPPE) or having additional layer of cut-resistant material Examples of cut-resistant material includes mixed yams or aramids.

[0015] In one embodiment, the nitrile granules are formed by acrylonitrile butadiene rubber. An advantage of providing the granules by means of nitrile, is to provide a glove with palm granules which is 100 % environmental, social and governance (ESG) compliant, soft, comfortable, food-safe and with excellent dexterity. Nonetheless, the granules may be made from latex or polyvinyl chloride (PVC), or a mixture thereof. Alternatively, the granules may be made from a combination of at least two of acrylonitrile butadiene rubber, latex, and PVC.

[0016] Advantageously, the granules have an average size between 10 to 60 mesh.

[0017] In general, if the surface tension of a coating is higher than that of the substrate, the coating will obtain the lowest possible common surface with the substrate. Based on the preceding description, the first nitrile layer is coated on a liner, while the second nitrile layer is coated on the first nitrile layer. In consideration of this, a nitrile compound with a suitable surface tension value is preferred. In one embodiment, the first nitrile compound has a surface tension value above 34 mN / m. In one embodiment, the second or subsequent nitrile compound has a surface tension value below or equal to 34 mN / m.

[0018] At least one of the preceding aspects is met, in whole or in part, by the present invention, in which one of the embodiments of the present invention is a method of producing a nitrile coated glove, the method comprising the steps of: preparing a glove liner to be coated on a former; roll-coating a first nitrile compound having a first viscosity on the liner by rotating the former in a bath of the first nitrile compound to obtain a first nitrile layer on the liner; drying the roll coated first nitrile layer; coating the first nitrile layer with a second nitrile compound having a second viscosity which is different to the first viscosity to form a second nitrile layer; spreading, prior to curing of the second nitrile layer, a plurality of nitrile granules on the second nitrile layer to form one or more friction areas to enhance the gripping characteristics of the glove; drying the high friction areas; and coating the or each high friction area with a third nitrile compound having a third viscosity to form a third nitrile layer and curing thereof.

[0019] In one embodiment, the method further comprising a step of adhering thermoplastic rubber (TPR) and / or thermoplastic urethane (TPU) at the back-hand area of the gloves.

[0020] Preferably, the method further comprising a step of adjusting the viscosity of the first, second and subsequent layers of nitrile compound in respective layers by adding diluent and / or thickeners thereto.

[0021] Preferably, wherein the step of spreading the nitrile granules is conducted by sprinkling the granules at a predetermined area on the second nitrile layer thereby forming the friction area.

[0022] In one embodiment, the nitrile compound of at least one of the first, second or any subsequent layers comprises at least one of acrylonitrile butadiene rubber, chloroprene, polyisoprene, or any combination thereof.

[0023] At least one of the preceding aspects is met, in whole or in part, by the present invention, in which one of the embodiments of the present invention is nitrile coated gloves produced according to the preceding description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention is illustrated, although not limited, by the following description of embodiments made with reference to the accompanying drawings in which:

[0025] FIG. 1 shows a front-hand with friction area of an exemplary pair of gloves of the present invention.

[0026] FIG. 2 shows a close-up of the nitrile granules of FIG. 1.

[0027] FIG. 3 shows a back-hand area of the pair of gloves of FIG. 1.

[0028] FIG. 4 shows in a larger scale a cross section of the friction area of FIG. 1.

[0029] FIG. 5 shows in a larger scale a cross section of the back-hand area of FIG. 3.

[0030] DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention provides gloves suitable for use in fisheries, oil and gas industry, food processing industry, household, but not limited thereto. The gloves can be ambidextrous or hand-specific.

[0032] Exemplary, non-limiting embodiments of the invention will be disclosed. However, it is to be understood that limiting the description to the preferred embodiments of the invention is merely to facilitate discussion of the present invention and it is envisioned that those skilled in the art may devise various modifications without departing from the scope of the appended claim. One embodiment of the present invention provides a nitrile coated glove comprising: a glove liner 10 (see FIG. 4 and 5); a first layer 100 of a nitrile compound which has been roll coated onto the liner, the first layer 100 being formed from a coating having a first viscosity; at least one second layer 200 of a nitrile compound coated onto the first layer 100, the second 200 and any subsequent layers 300, 400 having a lower viscosity of nitrile compound coating than that of the first layer 100; and one or more friction areas formed by a plurality of nitrile granules 201 spread on the second layer 200.

[0033] The gloves according to the present invention may vary in length to include long gloves, also known as elbow-length gloves, usually having a length of 60 cm to 68 cm. Nonetheless, it shall be understood that the gloves according to the present invention includes short gloves, commonly understood as wrist-length gloves, usually having a length of 33 to 39 cm. For long gloves, the first layer 100 is preferably roll-coated up to full length of the glove liner 10. Further, the second and third layer 200, 300 are preferably dip-coated from a finger area 202 up to palm area 203 of the gloves. Optionally, if desired, the second 200 and third 300 layer may dip-coated beyond a palm area 203 of the gloves, such as up to a wrist area 204 of the gloves. For short gloves, the first layer 100 is preferably roll-coated up to the full length of the glove liner 10, and the second and third layer 200, 300 are preferably dip-coated up to the palm 203 and / or wrist area 204.

[0034] In the present invention, the friction areas comprise mainly the front-hand areas, such as the palm 203 and / or the fingers 202 area. FIG. 1 shows an exemplary embodiment of the gloves whereby the nitrile granules 201 are provided at the palm 203 and fingers areas 202. Alternatively, the nitrile granules can be provided at only certain area of the gloves, such as at the thumb and fingers areas only, or only at the palm area. The nitrile granules can be provided in a random manner (as shown in FIG. 1 and 2) or in a specific pattern according to needs, such as a plurality of granules formed into patches (not shown) in zigzag, geometrical shapes, or the like. Preferably, the nitrile granules 201 have an average size between 10 to 60 mesh, more preferably 10 to 25 mesh. The granules 201 can be a mixture of fixed mesh sizes, or a mixture of a plurality of sizes, so as to form protrusions of various dimensions at the friction area. It shall be understood that the second nitrile layer 200 is roughen by granules 201 of relatively small sizes and also having protrusions formed by granules of relatively big sizes, as shown in close-up of FIG. 2. According to FIG. 1 and 2, the granules 201 can be felt and seen externally from an outermost nitrile layer of the nitrile coated gloves. More particularly, the granules 201 are spread on the second, wet nitrile layer of the glove. Preferably, the nitrile granules 201 are solid granules derived from acrylonitrile butadiene rubber. More preferably, the solid granules 201 are ground into the aforementioned sizes, and then spread on the second layer, followed by drying of the second nitrile layer 200. Preferably, the step of spreading the nitrile granules 201 is conducted by sprinkling or spraying the granules 201 at a desired area of the glove, thereby forming the friction area.

[0035] Another embodiment of the present invention provides a nitrile coated glove comprising a glove liner 10; a first layer 100 of a nitrile compound which has been roll coated onto the liner 10, the first layer 100 being formed from a coating having a first viscosity; at least one second layer 200 of a nitrile compound coated onto the first layer, the second 200 and any subsequent layers 300, 400 having a lower viscosity of nitrile compound coating than that of the first layer 100; one or more friction areas formed by a plurality of nitrile granules 201 spread on the second layer 200; and a thermoplastic rubber (TPR) and / or thermoplastic urethane (TPU) configured at the back-hand area of the gloves. The TPR and / or TPU are configured to provide extra protection for the gloves. Preferably, the TPR and / or TPU are provided at back-hand area of the gloves and being configured such that wearing the gloves are not obstructed to any noticeable degree as compared with a glove according to the invention that is not provided with TPR and / or TPU. Particularly, the TPR and / or TPU are configured as individual strips and / or patches 500 with foldable ridges 501 to be resemble joints of a hand, such as the knuckles, the carpal areas of a hand, as shown in FIG.3. The strips and / or patches 500 are adhered to the gloves, and the foldable ridges 501 may be squeezed or twisted following a hand movement, hence a movement of joints of the hands by a user wearing the glove will be substantially similar to a glove according to the invention that is not provided TPR and / or TPU.

[0036] In the present invention, the glove liner 10 may be made of cotton, terry cotton, rayon, fleece, or any combination thereof. For example, the glove liner 10 can be configured with cut-resistant feature by incorporating cut-resistant material, such as high-performance polyethylene (HPPE) into the liner. Alternatively, an additional cut-resistant material, such as mixed yarn or aramids, can be used to cover a cotton liner in order to render the glove being cut-resistant. According to FIG. 4, a cut-resistant material 11 is included underneath the liner 10 to provide a cut-resistant glove. In a position of use of the glove, the cutresistant layer 11 will face against a skin of the hand of a wearer.

[0037] In one embodiment, the nitrile compound of the first second or any subsequent layers comprises at least one of acrylonitrile butadiene rubber, chloroprene, polyisoprene, or any combination thereof. More preferably, acrylonitrile butadiene rubber present predominantly in the first, second or any subsequent layers. Optionally, chloroprene and / or polyisoprene may be added.

[0038] In the present invention, the viscosity of the first, second, third and the optional nitrile compounds may be adjusted by adding suitable amount of diluent and / or thickener to obtain a desired viscosity. The diluent used is preferably water. The thickener used includes aqueous acrylic thickeners suitable for nitrile latex. More preferably, the thickener provides a pseudoplastic (low shear) flow behaviour and viscosity stability for the nitrile compounds used in the present invention.

[0039] Preferably, the first viscosity ranges from 800 to 1200 mPa.s, more preferably 800 to 1000 mPa.s. The second and the third viscosity are relatively lower than the first viscosity. Optionally, the second viscosity and the third viscosity are the same. Preferably, the second viscosity ranges from 200 to 600 mPa.s, more preferably 400 to 600 mPa.s. Further, the viscosity of the additional nitrile compound may be relatively lower or within the range of the second or third viscosity. Preferably, the viscosity of the additional nitrile compound may be about 500 mPa.s.

[0040] In one embodiment, the first layer 100 of nitrile compound is formed by a first nitrile compound comprising carboxynitrile butadiene rubber having a relatively high surface tension value, which is above 34 mN / m. More preferably, 35 nM / m to 45 mM / m. The first nitrile compound enables a suitable adherence upon contacting with the glove liner. Additionally, the roll-coating step controls the amount and contact period between the liner 10 and the first nitrile compound. A combination of roll-coating step with the first nitrile compound is able to provide a coating of minimum thickness between about 0.1 to 0.2 mm on the liner 10. Such thickness is sufficient to seal the liner 10 without formation of an undesirable hard nitrile coating.

[0041] In another embodiment, the second 200 or subsequent layer 300, 400 of nitrile compound is preferably formed by a second nitrile compound comprising carboxynitrile butadiene rubber having a surface tension value below or equal to 34 mN / m, more preferably 25 mN / m to 33 nM / m. The second nitrile compound is suitable for a subsequent dip-coating step and for adherence of nitrile granules thereto. Preferably, the second or subsequent layer of nitrile layer has a thickness of about 0.06 to 0.15 mm.

[0042] The present invention also provides a method for producing the aforementioned glove, the method comprising the steps of: preparing a glove liner 10 to be coated on a former; rollcoating a first nitrile compound having a first viscosity on the liner by rotating the former in a bath of the first nitrile compound to obtain a first nitrile layer 100 on the liner 10; drying the roll coated first nitrile layer 100; coating the first nitrile layer 100 with a second nitrile compound having a second viscosity which is different to the first viscosity to form a second nitrile layer 200; spreading, prior to curing the second nitrile layer 200, a plurality of nitrile granules 201 on the second nitrile layer 200 to form one or more friction areas to enhance the gripping characteristics of the glove; drying the high friction areas; and coating the or each high friction area with a third nitrile compound having a third viscosity to form a third nitrile layer 300 and curing thereof. In another embodiment, the method further comprising a step of forming thermoplastic rubber (TPR) and / or thermoplastic polyurethane (TPU) at the back-hand area of the gloves. Optionally, the method may further comprise another step of coating the third nitrile layer 300 with a fourth nitrile compound and curing thereof.

[0043] More particularly, the glove liner 10 is prepared by wearing the liner on a suitable former. Preferably, a metal or ceramic glove former is used. Subsequently, there is a step of rollcoating a first nitrile compound having a first viscosity on the liner by rotating the former in a bath of the first nitrile compound to obtain a first nitrile layer 100, followed by drying at a temperature about 60 to 80 °C for about 10 to 20 minutes. Preferably, the rotation of the former is controlled such that the rotation enables coating of whole liner 10 (front and back) within a contact period between 1 to 10 seconds. This is to prevent over-penetration of the first nitrile compound on the liner 10, as compared to dipping technique. Thereinafter, the first nitrile layer 100 formed on the liner 10 is subjected to dip-coating in a second nitrile compound, followed by spreading the nitrile granules 201 thereon and then drying at a temperature about 60 to 80 °C for about 10 to 20 minutes to obtain a second nitrile layer 200. Additionally, the second nitrile layer 200 is subjected to dip-coating in a third nitrile compound and curing at a temperature about 60 to 90 °C for about 10 to 20 minutes to obtain a third nitrile layer 300. Optionally, the third nitrile layer 300 is subjected to dipcoating in a fourth nitrile compound and curing at a temperature about 80 to 120 °C for about 60 to 75 minutes to obtain a fourth nitrile layer 400.

[0044] According to the preceding description, the method further comprising a step of adjusting the viscosity of the first 100, second 200 and / or subsequent 300, 400 layers of nitrile compound in respective layers by adding diluent and / or thickeners thereto. In one embodiment, the viscosity of the first nitrile compound can be adjusted by adding suitable amount of thickener in order to achieve the aforementioned first viscosity. In another embodiment, the viscosity of the second nitrile compound can be adjusted by adding suitable amount of water and thickener hence achieving the aforementioned second, or lower viscosity as compared to the first viscosity. For example, the step of adjusting viscosity of the first nitrile compound is conducted by adding about 2 wt% to 5 wt % of thickener therein. In another example, the step of adjusting viscosity of the second and / or subsequent nitrile compound is conducted by adding about 3 wt% to 6 wt% of water and 3 to 6 wt% of thickener therein.

[0045] Preferably, the step of spreading a plurality of nitrile granules 201 is conducted by sprinkling the granules 201 at a predetermined area on the second nitrile layer 200 thereby forming the friction areas. The step of sprinkling the granules 201 can be conducted manually or automated by means of machinery. Hence, the present invention provides a nitrile coated glove which includes friction areas configured with nitrile granules 201.

[0046] In one embodiment, the method comprises a step of adhering thermoplastic rubber (TPR) and / or thermoplastic polyurethane (TPU) at the back-hand area of the glove. For example, TPR is adhered on the outermost cured nitrile layer, such that the TPR can be provided on the back-hand area of the gloves. As aforementioned, the TPR are provided in strips and / or patches 500 as shown in FIG. 3 and 5. The foldable ridges 501 provide space for movement of joints of a hand thereby providing flexibility in hand movement of a user. Conventional way of sewing TPR on fabric gloves may not be applicable in the present invention as sewing may puncture the nitrile layers. It is preferred that the TPR strips and / or patches 500 are adhered to the outermost layer of the glove by means of high-performance adhesives, such as high-performance polyurethane glue, or the like.

[0047] The method in the present invention further comprising steps of leaching the cured gloves to remove chemical remains thereof. Optionally, the method may further comprise steps of chlorinating the gloves using chlorine or sodium hypochlorite, followed by neutralization. The concentration of chlorine or sodium hypochlorite used may vary based on situation. For example, 100 to 500 ppm of chlorine or sodium hypochlorite can be used. The present invention may be embodied in other specific forms without departing from its essential characteristics. The described embodiments are to be considered in all aspects only as illustrative and not restrictive. The scope of the invention is therefore indicated by the appended claims rather than by the foregoing description. All changes, which come within the meaning and range of equivalency of the claims, are to be embraced within their scope.

Claims

CLAIMS1. A nitrile coated glove comprising: a glove liner; a first layer of a nitrile compound which has been roll coated onto the liner, the first layer being formed from a coating having a first viscosity; at least one second layer of a nitrile compound coated onto the first layer, the second and any subsequent layers having a lower viscosity of nitrile compound coating than that of the first layer; and one or more friction areas formed by a plurality of nitrile granules spread on the second layer.

2. The nitrile coated glove according to claim 1 further comprising thermoplastic rubber (TPR) and / or thermoplastic polyurethane (TPU) configured at the back-hand area of the gloves.

3. The nitrile coated glove according to any one of the preceding claims, wherein the nitrile compound of the first, second or any subsequent layers comprises at least one of acrylonitrile butadiene rubber, chloroprene, polyisoprene, or any combination thereof.

4. The nitrile coated glove according to any one of the preceding claims, wherein the highest viscosity of the second and any subsequent layers is lower than the lowest viscosity of the first layer.

5. The nitrile coated glove according to any of the preceding claims, wherein the first viscosity ranges from 800 to 1200 mPa.s.

6. The nitrile coated glove according to any of the preceding claims, wherein the lower viscosity ranges from 200 to 600 mPa.s.

7. The nitrile coated glove according to any one of the preceding claims, wherein the liner is made of at least one of cotton, terry cotton, rayon, fleece, or any combination thereof.

8. The nitrile coated glove according to claim 7, wherein the liner further comprises a cut-resistant material.

9. The nitrile coated glove according to any one of claims 1-7, wherein at least a portion of the glove further comprises a cut-resistant layer added to the liner.

10. The nitrile coated glove according to any one of the preceding claims, wherein the nitrile granules are formed by acrylonitrile butadiene rubber.

11. The nitrile coated glove according to any one of the preceding claims, wherein the nitrile granules have an average size between 10 to 60 mesh.

12. The nitrile coated glove according to any one of the preceding claims, wherein the nitrile compound for the first layer has a surface tension value above 34 mN / m.

13. The nitrile coated glove according to any one of the preceding claims, wherein the nitrile compound for the second or subsequent layer has a surface tension value below or equal to 34 mN / m.

14. A method of producing a nitrile coated glove, the method comprising the steps of: preparing a glove liner to be coated on a former;roll-coating a first nitrile compound having a first viscosity on the liner by rotating the former in a bath of the first nitrile compound to obtain a first nitrile layer on the liner; drying the roll coated first nitrile layer; coating the first nitrile layer with a second nitrile compound having a second viscosity which is different to the first viscosity to form a second nitrile layer; spreading, prior to curing the second nitrile layer, a plurality of nitrile granules on the second nitrile layer to form one or more friction areas to enhance the gripping characteristics of the glove; drying the high friction areas; and coating the or each high friction area with a third nitrile compound having a third viscosity to form a third nitrile layer and curing thereof.

15. The method according to claim 14 further comprising a step of adhering thermoplastic rubber (TPR) and / or thermoplastic polyurethane (TPU) at the backhand area of the gloves.

16. The method according to claim 14 or 15 further comprising a step of adjusting the viscosity of the first, second and / or subsequent layers of nitrile compound in respective layers by adding diluent and / or thickeners thereto.

17. The method according to claim 14, wherein the step of spreading the nitrile granules is conducted by sprinkling the granules at a predetermined area on the second nitrile layer thereby forming the friction area.

18. The method according to any one of claims 14 to 17, wherein the nitrile compound of the first, second or any subsequent layers comprises at least one of acrylonitrile butadiene rubber, chloroprene, polyisoprene, or any combination thereof.

19. Nitrile coated glove produced according to any one of claims 14 to 18.

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