A LATEX DIPPED ARTICLE CONTAINING A NATURAL MINERAL COMPOSITE WITH A MAGNETICALLY DETECTABLE PROPERTY AND METHOD OF MAKING

Abstract

A latex dipped article, specifically an unsupported glove having magnetically detectable property and its method of manufacturing is disclosed here. The glove contains at least one layer of elastomeric material that consist of a composition of evenly dispersed natural mineral composite containing; magnetite, illmenite, zircorn and quartz. The composition renders the article or small pieces of the latex dipped article magnetically detectable property.

Claims

1. A magnetically detectable latex dipped article/glove comprising at least one layer of a elastomeric material comprising an evenly dispersed natural mineral composite containing; magnetite, illmenite, zircorn and quartz.

2. A magnetically detectable latex dipped article/glove comprising at least one layer of a elastomeric material wherein the natural mineral composite of claim 1 comprises, Magnetite—>86.45%, Illmenite—7.29% as main magnetic detectable constituents.

3. A magnetically detectable glove comprising at least one layer of a elastomeric material wherein the natural mineral composite of claims 1 and 2 is incorporated into the latex compound in the form of a dispersion with the particle size range from 0.5 to 5 micron.

4. The natural mineral composite of claims 1 and 2 comprises; magnetic component comprises magnetite and illmenite and non-magnetic component as zircon and quartz which act as grinding medium to reduce the particle size of the natural mineral composite dispersion and as a result improves the sensitivity in terms of the magnetic constituent in the unit area of the glove.

5. A magnetically detectable glove comprising a layer of natural composite dispersion having the magnetic detectability of glove pieces as small as 5×5 mm detected by a metal detector calibrated for detecting 1.2 mm diameter iron sphere.

6. A magnetically detectable latex dipped article/glove of claims 1 and 2, wherein the elastomer used for the dipped article is made out of natural rubber latex, acrylonitrile butadiene rubber (nitrile rubber), chloroprene latex, synthetic polyisoprene latex, PVC or blend of above elastomeric materials.

7. A magnetically detectable latex dipped article/glove of claims 1 and 2 comprising; multiple layers wherein at least one layer comprises natural mineral composite or any combination of layers containing flock or without flock. The flock can be synthetic fibers or cotton or a blend of synthetic and cotton fibers.

8. A method of making a glove, which process comprises the step of incorporating natural mineral composite in the form of a dispersion with the particle size range from 0.5 to 5 micron to the elastomeric material, in latex dipping process and vulcanization process.

9. A latex dipped article/glove according to claim 6, wherein magnetic detectability of the glove pieces does not vary with time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0018] The magnetically detectable latex dipped article, particularly the glove is made using latex, standard sulphur/accelerator/zinc oxide and formulations with the natural mineral composite that confer magnetic detectability. The natural mineral composite is a by-product of the Illemite separation process from raw mineral sand. During Illmenite separation process, magnetite and other minerals having magnetic property are separated as by-products using a permanent magnet where the nonmagnetic mineral separates from the magnetic minerals due to its inherent magnetic property. The constituents are combined in a way that allows the mineral to stay distinct and identifiable. The composition is stated below in Table 1.

Composition of Natural Mineral Composite

[0019]

TABLE-US-00001 TABLE 1 Mineralogical composition of natural mineral composite, Constituent Weight % Magnetic Magnetite >86.45 Illmenite 7.29 Others 1.79 Non-magnetic Zircon 1.87 Quartz 2.60

[0020] The dispersion of the natural mineral composite, which has a particle size of 0.15 mm, is prepared by reducing the particle size to 0.5 to 10 micron preferably to below 5 microns. Presence of combination of magnetite and illmenite in reduced particle size, preferably below 5 micron, within a unit area of latex article/glove has increased the electromagnetically detectable property of the article. The surface of the natural mineral composite is organically modified using an anionic surfactant to enhance the compatibility with latex and to reduce the settling of the particles. Anionic surfactants such as natural salt of napthalene sulphonic acid, sodium diisobutyl napthalene sulfonate, alkyls napthalene sulphonate used as dispersing agents. The formulation of the dispersion made from the natural mineral composite is stated in Table 2 below.

TABLE-US-00002 TABLE 2 Natural mineral composite dispersion formulation Compound By weight % Natural mineral composite 45 Bentonite clay 1.25 TiO2 1.75 Anionic surfactants 3 Water 49

[0021] The constituents in the dispersion, magnetite and illemenite are the magnetic constituents which increases the magnetic detectability whilst zircon and quartz are the non-magnetic constituents that helps to reduce the particle size when preparing the natural mineral composite dispersion and thereby improve the magnetic sensitivity of the glove.

[0022] Dispersion of electromagnetically detectable natural mineral composite is introduced into the latex material such as natural rubber (NR), synthetic latex such as acrylonitrile butadiene rubber (nitrile rubber), chloroprene latex, synthetic polyisoprene (IR), polyvinyl chloride or blend of two or many different latex types.

Example 1

[0023]

TABLE-US-00003 TABLE 3 Composite of natural rubber latex- natural mineral formulation Compound phr Natural latex 100 KOH 0.15 Curing system(sulphur, 2.26 Accelerators and activators) Potassium salt of Stearate 2.5 Antioxidant 0.7 Natural mineral composite 50 dispersion Color pigment 0.3 Anti-forming agents 0.03 Viscosity modifiers 0.6

Example 02

[0024]

TABLE-US-00004 TABLE 4 Composite of nitrile buta diene rubber latex - natural mineral formulation Compound phr Nitrile rubber 100 Wetting agents 0.3 KOH 0.8 Dispersing agents 0.4 Curing system(sulphur, 6.2 Accelerators and activators) Antioxidant 0.75 Antiforming agents 0.01 Potassium salt of Stearate 2.5 Natural mineral composite 60 dispersion

[0025] The method of making the magnetically detectable article follows the conventional steps of glove manufacturing; and comprising the step of dipping the glove in the composite of latex—natural mineral wherein the at least one layer contains magnetically detectable dispersion in a particle size ranging from 0.5 to 10 micron and have magnetic detectability of 5×5 mm glove fragments detected by a metal detector calibrated for detecting 1.2 mm diameter iron sphere.

[0026] The process of making magnetically detectable glove is described below:

[0027] Coagulant dipping as an initial step former is dipped in a coagulant which is Calcium nitrate to facilitate the latex film formation.

Dipping of Composite of Latex—Natural Mineral Dipping

[0028] Then the former is dipped in the composite of latex-natural mineral to obtain a thin layer on top of the ceramic former.

Leaching

[0029] Gloves are leached in water at a temperature of approximately 50° C. to remove water soluble materials and excess calcium nitrate in composite of latex-natural mineral layer.

Curing/Vulcanization

[0030] Then the composite of latex-natural mineral layer expose to heat where improve the elasticity and the strength of the final product by vulcanization.

Stripping

[0031] Finish product is stripped from the ceramic former manually or automatically.

[0032] The glove is made according to the principles of the present invention disclosed. In yet another embodiment, a latex article having multiple-layers may be made wherein a composite of latex-natural mineral is sandwiched between two conventional compounded latex layers.

[0033] Processes described in example 1 & 2 can be used to construct the glove in following ways:

[0034] 1. Glove is constructed with a single layer of composite of latex-natural mineral

[0035] 2. Glove is constructed with a double layer where outer layer is with conventional compounded latex and inner layer with composite of latex-natural mineral

[0036] 3. Glove is constructed with composite of latex-natural mineral is sandwiched between two conventional compounded latex layers

[0037] 4. Glove is constructed with blend of natural and synthetic latex-natural mineral composite

[0038] 5. Glove is constructed with combination of natural and synthetic latex layers

[0039] 6. Glove with a half dipped of composite latex-natural mineral layer on the outer surface/inner surface or to any other length from the fingertips to the cuff

[0040] 7. Disposable glove version with latex-natural mineral composite material

[0041] 8. Fabric supported glove, with a composite coating of latex-natural mineral

[0042] 9. Flock lined glove where the inner layer of the glove with cotton flock line and composite of latex natural mineral

[0043] Thickness of the glove is varying with the number of dips in the latex-natural mineral composite and the coagulant concentration. In fabric supported glove, particular liners are cuts and sewn or woven. Fabric can be synthetic or natural fibers.

Metal Detection Sensitivity of Glove Made Out of as Per the Example 1 & 2

[0044] 1. 5×5 mm glove fragments prepared from above constructed gloves were detected by a metal detector calibrated for detecting 1.2 mm diameter iron sphere. [0045] 2. Detectability did not vary, along the length of the glove. [0046] 3. The dimensions of the fragment detected did not vary along the glove length. [0047] 4. 5×5 mm glove fragments were also be detected when it is buried inside a food container.

Thermal Oxidative Stability of Glove Made Out of as Per the Example 1 & 2

[0048] The glove having the said behavior, metal detectability does not affect significantly in the un-aged mechanical properties such as tensile, tear or flexibility.

[0049] The performance of the glove for un-aged and aged properties is measured according to the ASTM D 412:2016 standard

TABLE-US-00005 TABLE 5 Thermal oxidative stability data - Natural rubber-mineral composite layer Un- 70° Retention Test Parameter aged 7 days aged % Tensile strength(MPa) 31.3 23.8 76 Elongation at break (%) 900 1000 111 Modulus (100%) 1.0 0.6 60

TABLE-US-00006 TABLE 6 Thermal oxidative stability data - NBR latex - natural mineral composite layer Un- 70° Retention Test Parameter aged 7 days aged % Tensile strength (MPa) 20.4 21.3 104 Elongation at break (%) 650 800 123.7 Modulus (100%) 1.9 1.6 84

[0050] After aging for seven days at 70° C., over 70% of the original performances retained. Detectability does not change significantly with the time. Corrosion caused by the magnetic material in the glove is comparatively low compared to the synthetic magnetite.