Title of Invention

PROCESS FOR THE PREPARATION OF NON-WOVEN COATED ABRASIVE WEBS FROM NATURAL FIBRES

Abstract

ABSTRACT 589/MAS/2002 A process for manufacturing non-woven coated abrasive web from naturally occurring fibres comprising the steps of converting the naturally occuring fibres to soft, fibrous and fluffy web having a density of 0.2 gm/cc to 30 gms/cc by mechanical treatment and spraying an adhesive such as herein described, sprinkling a particulate abrasive material on the web and drying the abrasive coated web at a temperature less than 115°C to obtain a non-woven coated abrasive web.

Full Text

This invention relates to a process for the preparation of non-woven coated abrasive web from naturally occurring fibres. Coated abrasives are products wherein abrasive grains are coated on to a backing substrate by means of an adhesive bond. The backing substrate can be paper, woven fabrics or vulcanized fibre. It can also be non-woven webs made out of fibres. The prior art on these non-woven webs have described the use of a range of synthetic fibres and yam or threads made out of them as the backing substrate. This invention describes a process wherein naturally occurring fibres are used for the preparation of non-woven coated abrasive webs. The abrasive grains used can be flint, garnet, emery, aluminium oxide, sihcon carbide of defined range of particle size distribution. They can also be fine particulate of carbonaceous or siliceous powers. The adhesive for binding the grain to the substrates can be water based or other solvent based solutions of animal glue or synthetic resin solutions made with urea-formaldehyde, phenol-formaldehyde, alkyds, epoxies, acrylics, polyurethane or poly-vinyl alcohol or acetates either as emulsions or as liquid resins or solutions. The adhesive can be applied to the substrates either by full impregnation by dipping or by roller coating before and/or after grain coating or by spraying. The adhesive bonds can be dried for durations ranging between 30-150 minutes at varying temperatures ranging between 50 degree C to 120 degree C, to dry the resin film and liberate the solvents. The temperature also cures the resin film to enable firm adhesion of the resin film to the backing as well to the grain. The invention pertains to the backing of the non-woven web type of coated abrasives and the improvement in the choice of the material of construction of the non-woven web. So far, the non-woven maferials for these applications have been made of synthetic fibres such as polyester or polyamide type of materials. The coated abrasive products made out of them have been widely used for domestic utensil cleaning and other similar applications. After usage, these are discarded to the earth. On account of the slow bio- degradable rates of these synthetic materials in earth, use of these materials add to the already existing environmental problem of solid waste disposals. As a remedy to this problem, we have now found that it is possible to make non-woven coated abrasive products by replacing the syntheUc fibres with naturally occurring fibres either directly or by chemical, mechanical or physical modification of the naturally occurring fibres and use these for making non-woven coated abrasives. The natural fibres used for the above application can be made out of processed cloth, coconut coirs, banana fibres, sisal fibres or jute fibres. This invention specifically covers the use of the natural fibres made out of the above materials and using coated abrasive products out of them. In the process according to the invention the natural fibres are subjected to mechanical treatment to render them soft, fibrous and fluffy by means of vibro-mechanical devices. The resultant density of the fibrous and fluffy web materia! thus made is in the range of 0.2 gm/cc to 30 gm/cc. Accordingly the present invention provides a process for manufacturing non-woven coated abrasive web from naturally occurring fibres, such as herein described, comprising the steps of converting the naturally occuring fibres to soft, fibrous and fluffy web having a density of 0.2 gm/cc to 30 gms/cc by mechanical treatment; spraying an adhesive, such as herein described, on the web; sprinkling a particulate abrasive material on the web; and drying the abrasive coated web at a temperature less than 11 S'^C to obtain the non-woven coated abrasive web. The following are the illustrative examples which elucidate the above invention. These are by no means limiting the scope of the claims of the invention. Example-1 50 kgs of processed soft, fluffy coconut coir fibres made to the required level of web density of 0.25 to 0.38 gm/cc are snread on a table and sprayed with a 3% solution of polyvinyl alcohol till uniform distribution of the adhesive coat is ensured on the entire surface of the fibres. The dry adhesive added is within the range of 50-200% of the base weight of the fibre. The fibre with sprayed adhesive is then sprinkled with abrasive material of fme particulate size silica ash to increase the weight of the web to 40-250% based on the initial weight of the web. The web is partially dried to remove the solvent and passed through needle locking presses to compress the web. The web is then dried in a hot chamber at a temperature of 90 degree C for 2 hours and 115 degree C for a period of 3 hours and then slit into required strips for use a hand-usable abrasive pad. Optionally this hand pad can be bound using an adhesive spongy back-up pads to avoid irritation and discomfort to the user at the time of usage of the hand-pad. Example 2 65 kgs of processed, soft, fluffy sisal fibres made to the required web density of 0.45 to 0.65 gms/cc are spread on a table and sprayed with a 6.5% solution of poly-urethane (Desmocoll 176 from Bayer A G) till uniform distribution of the adhesive coat is ensured on the entire surface of the fibres. The dry adhesive added is within the range of 50-210% of the base weight of the fibre. The fibre with adhesive sprayed is then sprinkled with abrasive material of fine particulate size silicon carbide powder of mesh size 1000-1500 BSS to increase the weight of the web in a range of 40-220% of the initial weight of the web. The web is partially dried to remove the solvent and then passed through needle locking presses to compress the web. The web is then dried in the hot chamber at a temperature of 95'C for 2 hours and \25'^C for a period of 4 hours and then slit into required strips for use as a hand-usable abrasive pad. WE CLAIM : 1. A process for manufacturing non-woven coated abrasive web from naturally occurring fibres, such as herein described, comprising the steps of converting the naturally occuring fibres to soft, fibrous and fluffy web having a density of 0.2 gm/cc to 30 gms/cc by mechanical treatment; spraying an adhesive, such as herein described, on the web; sprinkling a particulate abrasive material on the web; and drying the abrasive coated web at a temperature less than 115°C to obtain the non-woven coated abrasive web. 2. The process as claimed in claim 1, wherein the quantity of the adhesive sprayed is from 50 to 210% by weight of the fibre. 3. The process as claimed in claim I, wherein sprinkling of particulate abrasive material is carried out such that the increase in weight of the finished abrasive coated web is 40 to 250% more than the weight of the fibrous fluffy web. 4. The process as claimed in claim 1, wherein the particulate abrasive material is silicon carbide powdsr of mesh size 1000 to 1500 BSS. 5. The process as claimed in claim 1, wherein the abrasive material is silica ash. 6. A process for manufacturing non-woven coated abrasive web from naturally occurring fibres, substantially as hereinabove described and exemplified.

Documents:

0589-mas-2002 abstract (provisional).pdf

0589-mas-2002 abstract duplicate.pdf

0589-mas-2002 abstract.pdf

0589-mas-2002 claims duplicate.pdf

0589-mas-2002 claims.pdf

0589-mas-2002 correspondence-others.pdf

0589-mas-2002 correspondence-po.pdf

0589-mas-2002 description (complete) duplicate.pdf

0589-mas-2002 description (complete).pdf

0589-mas-2002 description (provisional).pdf

0589-mas-2002 form-1.pdf

0589-mas-2002 form-19.pdf

0589-mas-2002 form-26.pdf

0589-mas-2002 form-3.pdf

0589-mas-2002 form-4.pdf

0589-mas-2002 form-5.pdf