| JP2011149011 | METHOD FOR PRODUCING AQUEOUS DISPERSION OF URETHANE-(METH)ACRYLIC COMPOSITE RESIN |
| WO/2001/085365 | METHOD FOR PREPARING RESIN-COATED SHEET |
| JP52077186 | FILMS COATED WITH RESINS |
Keshavlal, Mody Arvind (Kilfire House, C-17 Dalia Industrial Area, Off Link Roa, Andheri Mumbai 3, 400 05, IN)
Mukund, Khandwe Milind (Plot No. 29, MIDC Road "C", Street No. 1, Satpur Nasik 7, 422 00, IN)
Keshavlal, Mody Arvind (Kilfire House, C-17 Dalia Industrial Area, Off Link Roa, Andheri Mumbai 3, 400 05, IN)
| 1. | A process for manufacturer of a protective covers comprising of PP (Polypropylene) fabric coated / laminated with TPO compound, henceforth termed as 'coated fabric', the TPO (Thermoplastic olefin) compound coated lamina can be coated fabric can be between 1201500 gsm. The composite form can be stitched, welded (thermosealing) hemmed to design a required shape of required size and geometry, henceforth referred as 'fabricated structure'. The coated / laminated fabric can be stitched or welded or fixed with any kind of fixtures to other materials like fabrics, plastic or metal sheets. The fabricated structure of coated fabric may be fixed with eyelets / grommet and ropes if required;. |
| 2. | A process as claimed in claim 1 where is PP fabric made up using texturized, micro or filament yarn, solution or dope dyed or natural undyedwhite;. |
| 3. | A process as claimed in claim 1 wherein PP fabric consisting of blend of two or more yarn made out of other synthetic or natural polymers in any form viz. mono or multifilament, texturized, micro or nano;. |
| 4. | A process as claimed in of claim 1 wherein TPO (Thermoplastic Olefin) layer consisting of virgin TPO (reactor modified) or blend of virgin TPO with additives and other olefin polymers or copolymer;. |
| 5. | The use of fire / insect / microbe/ UV resistant additive in TPO layer as mentioned in claim 4;. |
| 6. | The use of woven, nonwoven PP fabric and blends made out of yarns as mentioned in claim 2 & 3 . |
| 7. | The use of coated fabric for fabrication of item viz. Tarpaulins, vehicle, Tarpaulins, Agriculture covers, Fumigation sheets, Awnings, Canopies, Tents, Bio Gas Covers etc;. |
| 8. | The use of ropes / loop or any material stitched, heat sealed or fixed by any means to the coated fabric as per claim 1 & 7 . |
| 9. | The use of eyelets / grommets or fasteners of any metal / alloy or polymer to the fabricated structure as per claim 1 & 8 . |
| 10. | Recycling of coated fabric after use as per claim 1 by means of melting / granulating process;. |
PRIOR ART
Use of coated fabrics in manufacture of protective covers has a long history. The products mainly categorized as PVC coated fabrics, PU coated fabrics, acrylic polymer coated fabric, wax coated fabrics (canvas) and rubber coated fabrics. The common usage of protective covers are for example (i) Tarpaulins (ii) Vehicle covers or truck tarpaulins (iii) Tents (iv) Agriculture coverings and fumigation sheets (v) Awnings (vi) Canopies, Tents, Covers etc. In all the types of coated fabrics, fabric component impart desired mechanical property, i.e. Breaking strength, tearing strength, bursting strength, dimensional stability etc. There are number of types of yarns used for manufacturing a fabric; they are polyester, nylon (polyamide), cotton regenerated celluslose etc. There are number of types of processes that are used in manufacturing a fabric, they are weaving, knitting and random laying of fibers to make a non-woven. The mechanical properties desired in coated fabrics are decided by Various properties of fabric used viz. weight, type of yarn, structure whether monofilament, multifilament or texturised, twists, polymer material property like crystallinity, chemical and thermal resistance etc. One can choose a fabric material from almost unlimited options available for the purpose of coating as per the end usage requirement.
The coating formulations are based on main polymer categories viz PVC (Polyvinyl Chloride), PE and other Poly olefins, PU (Polyurethane), Acrylics, Rubber (natural or synthetic) and waxes. Cotton fabric coated with wax formulations are called canvas, is a most common and primitive form of coated fabric. With the invention of new materials and their formulations the number of options available are plenty. The most common are PVC and rubber based formulation where a number of additives are used to prepare a
suitable fluid to coat on a fabric. The categories of additives are - fillers, pigments and dyes, solvents, plasticizers and functional additives are used in almost all types of polymers to formulate a compound having desired property. The coatings impart or modify surface properties, barrier properties and aesthetics of a coated fabiic for the required function or end use.
There are number of processes used for coating a fabric but the main categories are two (i) Solution coating including plastisols in the case of PVC (ii) Hot melt coating viz calendar coating including cold calendaring in the case of rubbers. These processes are generally followed by heating or cooling. The process of coating can be used on one or both the sides of fabric. Surface properties of the coatings can further be modified using physical treatment like embossing, chemical treatment like lacquering, printing, metallizing or film or foil lamination.
There are number of ways to fabricate an article out of coated fabric for protective cover application. Since individual application demand specific size and shape whereas coated fabrics are manufacture in standard width and lengths, depending on the process of manufacturing, joining two or more pieces are required. The standard processes are- joining with adhesives, stitching, hot air or hot wedge welding, HF/RF welding etc. Use of fixtures of desired shape or size viz eyelets, grommets, D rings, brackets, webbings, ropes are known and are quite common.
The biggest problem is, disposal of waste, generated after the use of coated fabrics. Recycling of coated fabrics is not an easy or a common task. In almost all of the cases the family of polymer used in manufacturing a fiber and coating compound are heterogeneous hence their physical mixing to regenerate in the form of recyclable goods, is not possible even by applying high temperature or pressure. The second option, though not environment friendly remain to dissolve, but again common solvent or mixture of solvents
cannot dissolve entire coated fabric for recycling purpose. There are solvents available to partly dissolve a coating but it is not an economical and environmentally friendly process, because of volatility of solvents. The only option remains to safely incinerate the waste, which has long-term economic effects, if all the precautions are taken from environmental point of view.
The Patent GB 1340465 discloses the method of making Tarpaulin cover for truck frame, which comprises of two angle sectioned horizontal side.
United states Patent 2594910 which covers construction pail to prevent leakage of rain water into the load and which have track ways that would binding of sliding supports.
Canada Patent No 767,537 discloses the reinforced retractable cover which provides depending extensions of the fabric cover material outside the box walls. But its tracks do not allow free sliding when the box sider are distended and also its constructions requires bulky and costly mountings, particularly ridge pole supports.
The cited document WO 9633882 discloses a retractable cover system for open topped container, which comprises of a plurality of bows to which cover is attached. Spanning the open top and supporting the cover, each bow having guide at its two ends.
However the conventional methods used have many disadvantages over the present invention. Some of which are mentioned below :
Recycling of the material is very difficult. Hence conventional material is not environmental friendly.
The conventional material is heavy by weight as density of PVC, PU and rubber is high.
' JPO coated PP Fabric ] ; poor thermal ageing properties, trantre
The TPO compound used in present invention have good multiaxial strain. .
The present invention Process for Manufacture of Protective Covers using TPO compound coated PP Fabric" is developed with a goal to overcome the disadvantages of the conventional protective covers and provide a better alternative.
The first objective of the present invention is that recycling of the material should be easy and it should be environmental by friendly.
The second objective of the present invention is that it should be light weight, density of material should be low.
The other objective of the present invention is that it should have outstanding resistance to low temperature applications.
The present invention should have excellent UV and thermal ageing properties.
The present invention should have high dimensional stability.
It should have good tear resistance.
Olefin polymers are most chemical resistant inert material available in their commercial category. Recycling of the material is easy and standard processes are known for the solid waste management, hence more environmental friendly. The aliphatic content makes them inert toward UV degradation and UV stabilizer can be added during processing if required.
The density of material is low as compared to PVC, PU or rubber, hence for the same volume these are light weight option for article design i.e. fabricated structure.
The chemical inertness is also advantageous for biological resistance and the coated fabric is resistant to gram-positive and gram-negative bacterium.
The TPO compound in formulated as well as in virgin form and the substrate used for coating i.e. PP fabric are from the same family of aliphatic olefin polymers. Hence are quite compatible.
Manufacturing a coated fabric offer good adhesion between coating layer and fabric layer. The thermo sealed joints are very strong in nature in either of the cases i.e. both side coated or only one side coated fabric with TPO compound. This feature of compatibility also makes the recycling process easy.
The TPO compounds are new generation of materials, which have benefits of rubber and processibility of thermoplastics. Absence of plasticizers, vulcanizing agent, isocyanate crosslinker which are basic necessity of PVC 5 Rubber and PU / acrylics respectively makes this TPO coated PP fabric more environmental friendly. The low density means ease of handling of finished articles and long term fuel savings for air boren articles.
The present invention should have high flexibility without using plasticizer.
Present invention should have 25 % lower density.
The present invention should have improved low temperature flexibility and puncture resistance.
It should not use any toxic ingredients and no toxic vapour formation on burning.
It should have better processibility so that the production can be much faster than rubber.
It should have better UV resistance due to non-existence of conjugation.
The present invention is resistive against microbe attack due to absence of Polymerization impurities in the case of synthetics and natural impurities.
DESCRIPTION
The present invention relates "Process for Manufacture of Protective Covers using TPO compound coated PP Fabric" can be explained with the help of figure 1 & figure 2 of accompanying drawing.
Figure 1 shows cross section of single side coated fabric.
Figure 2 shows cross section of double side coated fabric.
Figure 1 & 2 illustrates TPO compound (1), Poly Propylene fabric (2).
The fabric material used for coating is PP based. PP based yarns are produced by many manufactures all over the world including India. PP yarns are available in monofilament, multifilament, twisted, texturized, dope dyed as well as natural in colour. All types of yarns are used in manufacturing fabric required for coating. The weight of fabric, thus made, was ranging from 20 to 600 grams per square meter (gsm). All the types of fabric manufacturing processes are used viz. weaving, knitting and random laying fibers in the case of non-wovens.
The coating consists of number of thermoplastic compounds formulated using well known base polymers viz. PP. homo and copolymers manufactured using various types of catalysts based processes, Engage® Chemigum®. One of the formulations is tabulated and discussed below as an example. The filler and other additives are mixed as per the product requirement.
Jn the TPO compound rmulations, for 100 parts of PP home ymer or co-polymer, Engage 10-300 parts by weight, Chemigum P 81, 0-500 parts by weight, precipitated CaCO 3 0-100 parts by weight, Carbon black / TiO 2 or colorant 0-30 parts by weight, UV- stabilizer Tinuvin 783 0-10 parts by weight, wax based lubricant 0-20 parts by weight are added first in a twin screw extruder. The processing temperature of the zones and die head was ranging from 130-220° C, suitable mesh filters were used. A typical formulation and General properties of TPO compound are listed in tables NO. I and II. Table I TPO compound formulation :
Table II
General property range of TPO compound :
The granulated form of TPO compound was used for calendar coaBng of PP based fabric. The granulates were fed from a single screw extruder over a two roll calendaring machine using a suitable die. The temperature of extruder was kept between 130-30O 0 C and calendar roll temperature was kept between 130-250° C. The pressure for calendaring was kept between 10-100 kg. The speed of coating was between 2-55 meters per minute. The TPO compound was either coated on one side or both the sides of the PP based fabric. The weight of coating on either side or both the sides of the PP based fabric. The weight of coating on either' side was between 10-500 gsm. The weight of coated fabric was between 120-1500 gsm. The properties of a typical coated fabric is given in table No. III.
Table III
Specified Properties of Coated Fabric
Fabricated protective covers which were exposed in environment for 6 months were collected and metallic parts were removed. The coated fabric thus obtained was shreddedinto pieces on a standard grinding machine. The shredded pieces were washed with water and dried. The pieces of coated fabric were extruded into strands using a single screw extruder maintaining a temperature gradient of 130-250 0 C, and granulated. The granules can be used as thermoplastic material for extrusion or injection molding. The granules were found compatible with PP, LDPE, HDPE. The typical properties of recycled granules are tabulated in table IV.
Table IV
Properties of Recycled Material :