|Title of Invention||
COATING COMPOSITION FOR SPINNING ROLLERS
|Abstract||A coating composition for spin rollers comprising a cross linking compound triphenylmethane 4,4',4"-triisocyanate and a diluent such as organic solvent in definite proportions of said triphenylmethane 4,4',4"-triisocyanate : diluent in the ratio of 1:3 and mixing these solutions to form a viscous mixtures with viscosity ranging between 3-3.5mPa"s.|
|Full Text||FORM -2
THE PATENTS ACT 39 OF 1970
SECTION-10, RULE 13 COATING COMPOSITION FOR SPINNING ROLLERS
SRIDHAR VAIDYANATH Of 14/221 "SURYALAYA", SION EAST, MUMBAI 4000022
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE
Field of invention
The present invention relates to a coating composition for spinning rollers used to spin yarns and more particularly a coating composition used to prevent yarn or fibers from lapping in the rubber rollers used in spinning in textile industry.
Background and Prior art:
In textile Industry, yarns are spun where the yarns or fibers are passed to series of rollers rotating at a greater speed or relatively higher than the previous one. The yarn is passed through the rollers and spun into a continuous yarn before taking for further processing in textile industry. The spinning rollers have a bottom metal roller with grooves and the top roller is mounted with synthetic rubber. When yarns particularly cotton/polyester passing through these rollers, they lap around the top rubber rollers causing yarn break resulting in poor quality of spun yarn. This process is commonly known as roll lapping in textile industry. Roller lapping results in fluff accumulation in Comber, Draw frames. The fluff accumulation results in decreased yarn quality to about 30 to 40%. Also that high fly liberation from the yarn makes the environment very unhealthy.
Sharp knifes are used to remove roller laps, which damages the rubber rollers and reduces the life of rubber roller.
Mills in order to control roller lapping were running the machines at about 30% lower speed than the optimum possible. The mills also tried to under spin by using higher raw material. This resulted in loss of productivity as well as competitiveness.
Berkolising technique was also used to control roller lapping, in which rubber roller were exposed to ultraviolet rays for 20-45 minutes. The effect lasted till the handling of the roller. The treatment required special machine and the replacement cost of UV tube was very high.
The other mechanical development in draft zone could solve problem in one particular mixing and did not offer universal solution for all the mixing. Adopting them would have reduced mills ability to spin all variety of counts as per market demand. These modifications needed additional cost and were very difficult to maintain.
Currently in textile industry when such problems arise, the spinning machines has to be stopped and mechanically cleaned resulting in shut down of the machine for minimum of 4-6hours which ends up in loss of production. In GB patent no 142336 and 277151 rollers and roller heads, is mounted between the bottom front drawing-roller and the clearing-roller of spinning frames, such as ring frames and mules and is rotated in the same direction as, at a greater surface, speed than, the drawing roller and delivers it to the clearing-roller. As the rollers rotate faster than the front rollers, the end is attenuated, thereby facilitating piercing. The roller is mounted in a bracket bolted to the roller stand, and the clearing-roller is carried in spring supports. All these prior art invention uses mechanical means, which needs
additional attachment to the machine thus increasing the cost as well as maintenance time.
In US patent 6,51600 teaches devices for cleaning of a spinning rotor independently of the support of the spinning rotor, a rotary drive is selectively movable into and out of contact with an outer rotor surface via entraining elements for imparting rotary movement to the spinning rotor. The entraining elements are arranged such that radial forces produced by the contact are mutually cancelled. The entraining elements are advantageously attached directly to the electric rotor of the rotary drive
Apart from mechanical means there are no prior arts dealing any chemical composition that is applied to the rubber rollers to prevent roll lapping of the yarns. Conventionally roller varnish is applied but this fails to meet the stringent requirement of processing on latest high-speed machines. Also the effect lasts only for few hours resulting in frequent application and frequent stoppage of machines. Hence there is a need to provide composition that can be applied to the rollers for preventing lap rollers.
It is an object of the present invention to provide a novel coating
composition for rollers from preventing yarn lapping.
It is also an object of the present invention to provide a coating composition
for rollers where it can be applied at ease.
It is also another object of the present invention to provide a coating
composition for rollers that uses less quantity.
Yet another object of the present invention is to provide a coating
composition for rollers that last for longer duration.
Still another object of the present invention is to provide a coating
composition for rollers that are less expensive.
Yet another object of the present invention is to provide a coating
composition for roller that requires very less production loss.
These and still other features and advantages of the present invention will be apparent from the description, which follows. The following description is of the preferred embodiments.
SUMMARY OF THE INVENTION
The present invention relates to a coating composition for spin rollers comprising a cross linking compound such as poly isothiocyanates and a diluent such as organic solvent in definite proportions of polyisothiocyanates .diluent and mixing these solutions to form viscous mixtures and applying the mixtures on to the rollers that cures at room temperature to prevent roll lapping of yarns.
DETAILED DESCRIPTION OF INVENTION
The present invention deals with a novel composition that can be applied as coating composition to the rubber rollers of the spinning machines. The composition comprises a cross linking compound such as poly isothiocyanates and a diluents such as organic solvents mixing these
compounds at a definite proportion to form a solution and applying the mixture to the rubber rollers within say 4 hours before hardening onto the rubber rollers. The mixture on application forms an effective cross-linking with the help of the poly isothiocyanates with the rubber components to form a thin film. The thin film coating on the rubber prevents the yarn from forming lapping on the rollers very effectively.
The composition of the present invention when applied on to the rubber roller forms a thin film. Normally the rubber of the rollers carries a static charge and when the yarn is rolled onto the rubber roller, roll lapping occurs due to the opposite charge of the yarn fibers. Incidentally the inventors have found out that the novel composition comprising mixtures of poly isothiocyanates and organic solvents provides a thin film on the rubber coating thus preventing the static charge. The thin film produced is very effective and lasts for more than 20 days.
The composition of the present coating composition is prepared at a definite proportion. Although several proportion can be made the inventor has surprisingly found a proportion of 1:3 w/w of polyisothiocyanate .diluent to be effective coating composition that can be applied before hardening. Although other proportion can be tried the most preferred proportion is 1:3 which can be applied with sufficient time before hardening.
The poly isothiocyanate used in the present invention belongs to an aromatic polyisocyanate selected from the group such as polyisocyanurate of toluene of diisocyanate in ethyl acetate, tris(p-isocyanatophenyl)thiophosphate in ethyl acetate, poly isocyanurate with aliphatic and aromatic NCO groups in
ethyl acetate, m-xylylene diisocyanate, m-tetramethylxylylene diisocyanate known as meta-TMXDI available from Cytec Industries, Inc., Stamford, Conn.,. More preferably, the polyisocyanate is an aromatic polyisocyanate based on ethyl acetate and more preferably the polyisothiocyanate is triphenylmethane-4, 4',4"-trisiocyanate in ethyl acetate sold in trade name Desmodur® RE sold by Bayer. Preferably, the amount of polyisocyanate ranges from about 0.2 to about 10 percent and more preferably 0.2% to 27% by weight based upon 100% total weight of coating mixture.
Suitable diluents that can be used according to the present invention can be selected from such as The organic solvent used in the inventive composition is not particularly limitative provided that the above described cross linker polyisothiocyanate can be dissolved in the solvent. Examples of suitable organic solvents include ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl isoamyl ketone, 2-heptanone and 1,1,1-trimethyl acetone, polyhydric alcohols and derivatives thereof such as ethyl-enegrycol, ethyleneglycol monoacetate, diethyleneglycol and diethyleneglycol monoacetate as well as monomethyl, monopropyl, monobutyl and monophenyl ethers thereof, cyclic ethers such as dioxane and esters such as ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate and ethyl 3-ethoxy-propionate and combinations thereof. More preferably the solvents uses is chloro benzene solvents and most preferably monochloro benzene. Preferred amounts used to prepare the composition using the solvent according to the present invention is 3 parts to 1 parts of isothiocyanate.
The composition of the present invention requires a curing time of 6hrs to 24hrs and more preferably 10 to 24 hrs and the curing temperature is between 25 to 30 °C and most preferably between 27-30oC.
The composition of the present invention that are suitable to the rollers comprising rubber material belonging to the group such as PVA, EVA, polyurethane, poly butadiene, polystyrene and combinations thereof and more preferably rubbers made of polyurethane.
The composition prevents various yarns from roll lapping during spinning process. Various yarns where the novel coating composition is used to prevent roll lapping belong to such as cotton, rayon, polyester, polycot, terry cot, polyester blends and cotton blends and combinations thereof. More preferably the composition can be applied to yarns such as cotton and polyester blends with polyester, viscose and cotton.
Optionally suitable film formers can be used to form a uniform film over the rubber roller. Film formers that can be used in the present invention belongs to methyl cellulose, ethyl cellulose, hydroxy propyl cellulose and combinations thereof.
Optionally suitable antioxidants can be used in the composition to prevent and oxidation suitable antioxidants that can be used in the present invention belong to Butyl hydroxy toluene, di butyl hydroxyl toluene, sebacic acid, tocopherol Butyl hydroxyl, bisphenon derivatives, 4,4'butyledene bis (5-methyl-6-t-butyl phenol), arylamines such as Phenyl -x-napthylamine,
phenyl-b-naphthylamine, or piperonyl butoxide, phosphonates, diaolyl thio di propionate, disterayl thio di propionate and mixtures thereof.
The cross linker and diluent can be packed in a pet or glass bottle separately where the user before using mixes in 1:3 proportions of the cross linker and diluent to prepare the coating composition of the present invention. It is also possible to provide a marking in the bottle containing cross linker where the user dilutes the cross linker up to the mark to prepare the coating composition. It is also possible to provide the cross linker and the diluent in tubes where the user uses the chemicals in the prescribed proportion to prepare the coating composition. It is also possible to provide the composition in aerosol form where the mixture can be sprayed on to the rollers to form the film.
The following example describes the invention in detail but it should be understood that this invention is by no means limited by the example. Example 1
Weighed quantities of poly isothiocyanate solution preferably of triphenylmethane 4,4',4"-triisocyanate in ethyl acetate is weighed and mixed with monoclorobenzene solvents in different proportions. The proportions studied ranged between 1:1, 1:2, 1:3,2: 3 parts of triphenylmethane4, 4', 4"-triisocyanate: monochlorobenzene mixture is prepared and about 20mg of the mixed solution is applied to the rubber rollers of the spinning machine. The rollers are allowed to cure for about 24 to 48hrs at room temperature (between 27-30oC). After this period, the yarn is spun over the rollers. From this the percentage of rollers where lapping observed is calculated with reference to total breaks and the frequency with which the roller lapping
occurred in roller with and without application and also at different
proportions is observed for different yarn types.
Table 1 Effect of different proportion of coating composition on the roller
From the table it is clear that 1:3 proportions showed a lesser harden time and the spun yarn length and yarn weight were maximum indicating there is no roller lapping for about 20-25 days.
Table 2 Effect of different proportions of coating composition on lapping frequency of different yarn types
CLAIMS I claim
1. A coating composition for spin rollers comprising a cross linking compound triphenylmethane 4,4',4"-triisocyanate and a diluent such as organic solvent in definite proportions of said triphenylmethane 4,4',4"-triisocyanate : diluent in the ratio of 1:3 and mixing these solutions to form a viscous mixtures with viscosity ranging between 3-3.5mPa"s.
2. A coating composition for spin rollers as claimed in claim 1 wherein the organic solvent belongs to group belonging to chlorobenzene solvents.
3. A coating composition for spin rollers as claimed in claim 2 wherein the chlorobenzene solvent is monochlorobenzene.
4. A method of coating spin roller comprising the steps of applying a layer of coating composition on to spin rollers comprising a cross linker selected from polyisothiocyanate such as triphenylmethane 4,4',4"-triisocyanate and a diluent selected from chlorobenzene solvent, mixing them together in 1:3 ratio and applying the mixture onto the spin rollers and allowing them to cure for 24-48hrs at temperature ranging between 27-30°C
5. A coated film obtainable by the method as claimed in claim 4.
6. A coating composition substantially as herein before described with reference to claiml, and accompanying examples
7. Date: 22-02-07
|Indian Patent Application Number||1319/MUM/2004|
|PG Journal Number||28/2007|
|Date of Filing||10-Dec-2004|
|Name of Patentee||SRIDHAR VAIDYANATH|
|Applicant Address||14/221, "SURYALAYA", SION EAST, MUMBAI,|
|PCT International Classification Number||G03F 7/04|
|PCT International Application Number||N/A|
|PCT International Filing date|