DESC:Field of the Invention
The present invention relates to the field of fabrics, and more particularly to a process for preparation of self-cushioning automotive fabrics.
Background of the Invention
Various kind of automotive fabrics are available in market such as woven, knitted or non-woven fabrics that provide both, visual as well as aesthetic properties to automotive products. Further, is it desirable that the seat cover fabrics should be un-creased & cushioned, for which the seat cover fabrics are usually laminated with low density polyurethane foam with the thickness varying from about 2mm to 10 mm to achieve seat covers with attractive sew lines. Furthermore, to help seat cover fabric slide along with the sewing machine surface during sewing, the scrim is also laminated with the other side of polyurethane foam. The fabric for seat cover is used as tri-laminates, and for door casings used as bi-laminate i.e. without scrim.
Polyurethane foam is adhered to textile material by flame lamination technique. The polyurethane foam passes over the flame and burnt at around 950°C wherein the foam melts and adheres with the textile material by calendaring together. This process involves gaseous emissions of carbon and isocyanate fumes which are very harmful to humans and environment.
Polyurethane foams are made with an aromatic isocyanate, hence burning of the same produces isocyanates fumes, exposure to which cause skin and mucous membranes irritation, chest tightness and breathing difficulties. Isocyanates include compounds classified as potential human carcinogens and known to cause cancer in human and animals.
Another disadvantage is that the process produces solid bond layers with little porosity, making the laminate stiff, as well as process includes calendaring with fabric after burning the foam to adhere, which causes flattening of fabric surface because of which tactile behaviour of face fabric deteriorates. The scrim which is laminated with the other side of foam causes creasing in the fabric after repeated use.
Further, attempts have been made to reduce seating discomfort by providing a cushion that has a substantially continuous and uniform thickness. Such cushions may be made of, for example, foam or other materials. Such cushions, while softening the seating surface over that of a solid surface, substantially block air flow to the person's posterior, thereby adding to the person's thermal and sweating discomfort. In addition, existing seat cushions, when made from foam, the seat cushion may not have a sufficient level of rigidity to support the user without bending or collapsing the seat cushion structure.
Furthermore, the existing fabrics and processes include steps having solvent free aqueous polyurethane dispersions, however comprises of fully formed polyurethaneurea with blocked isocyanate end groups. Typically, such polyurethanes are either fully formed non-reactive polymers or reactive isocyanate-terminated prepolymers. Such reactive polyurethane adhesives often require extended curing time to develop adequate bonding strength, which can be a disadvantage in manufacturing processes. In addition, the isocyanate groups of the polyurethanes are known to be sensitive to moisture, which limits the storage stability and reduces the shelf life of the product incorporating such polyurethanes. There are existing processes that discloses an aqueous polyurethane dispersion for adhesive bonding in wet and dry laminations stated to have superior coatability, adhesive strength and heat resistance. Said dispersion contains a substantial amount of organic solvent—methyl ethyl ketone (MEK). Though the dispersion is stable in storage, and the film formed from the dispersion has good tensile properties. However, this dispersion still has organic solvent present and the longer curing time needed is unsuitable for fabric bonding and lamination in practice.
Furthermore, there are disclosures stating method for making a polyurethane dispersion that is free of organic solvent such as N-methylpyrrolidone (NMP). However, the composition is limited to a prepolymer having low free diisocyanate species, such as methylene bis(4-phenylisocyanate) (4,4'-MDI). The process to produce such a prepolymer with low free diisocyanate is complicated and such processing also requires short path distillation of the free diisocyanate and is thus not economical in producing a prepolymer for making a polyurethane dispersion.
There are known methods for making cushion assemblies which solve the problems such as discomfort of the cushions due to heavy structured foams, reduced life span of the seat cushions due to foam deformations, etc.
Accordingly, there is a need for an automotive fabric preparation process which overcomes all the drawbacks of the prior art and which provides desired properties to the automotive fabric.
Summary of the invention
Accordingly, the present invention in one aspect provides a process for preparation of self cushioning automotive fabric. The process comprises of providing a textile fabric having a first layer of polyurethane. Next step includes mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents together and embedding silver nanoparticles, to form silver nanoparticle-embedded semi-solid second foam. The silver nanoparticle- embedded second foam is applied at a rear side of the first layer by knife over roll coating technology and the above layer of the above step is cured at a predefined elevated temperature to the obtain solid self cushioning automotive fabric with embedded silver nanoparticles .
The textile fabric having the first layer of polyurethane comprises the steps of mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents together to form a semi solid foam solution; applying said semi solid foam over the rear side of a textile fabric as a first layer and drying said first layer.
In another embodiment, the aqueous polyurethane solution is in an amount ranging from 800 parts to 1100 parts. In an embodiment, embedding the semi-solid second foam with silver nanoparticles comprises adding a predefined amount of silver nanoparticles in a predefined amount of fixing agents to obtain a silver nanoparticles solution. Mixing of the silver nanoparticles solution with the semi-solid second foam to form the silver nanoparticle-embedded semi-solid second foam.
In an embodiment, the silver nanoparticles are in a range from 10 parts to about 15 parts. The curing temperature is from 80 °C to 150°C. The drying is carried out at a temperature of 80-110°C.
The foaming agent is selected from alpha olefin sulphonate, surfactant foaming agents, Ammonium stearate. The fixing agent is the non-ionic melamine resin cross linker. The process of the present invention is devoid of isocyanate particle formation.
In another aspect, a self cushioning automotive fabric is disclosed. The fabric comprises a textile fabric with a polyurethane as a first layer, a second foam layer, wherein the second layer is formed by mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents, followed by air agitation, to form a even foam solution for obtaining the second foam. The second foam is an aqueous porous foam layer of polyurethane embedded with silver nanoparticles to form second form layer (120). The first layer is selected from woven fabric, knitted fabric or non-woven fabric. The fabric is selected from the group comprising of polyester, cotton, polyamide and/ or their blends. The second foam is selected from the group comprising of polyurethane aqueous solution, wherein the aqueous polyurethane is selected from the group comprising of water, anionic polyurethane binders, and the like. The second foam is a layer of polyurethane with the wet GSM range of 450 to 700 gm/m2. The silver nanoparticle- embedded second foam layer (120) has a GSM range of 100 GSM to 500 GSM.
Brief Description of Drawings
FIG. 1 is a cross-sectional view of an automotive fabric in accordance with a preferred embodiment of the present invention;
FIG. 2 is a graph showing comparative study on the wicking property of the fabric (100) of the present invention;
FIG. 3 is a graph showing comparative study on the air permeability of the fabric (100) of the present invention;
FIG. 4 is a graph showing comparative study on the improved of the fabric (100) of the present invention; and
FIG.5 is a graph showing comparative study on the anti-microbial property of the fabric (100) of the present invention.
Description of the invention
Although specific terms are used in the following description for sake of clarity, these terms are intended to refer only to particular structure of the invention selected for illustration in the drawings, and are not intended to define or limit the scope of the invention.
References in the specification to “preferred embodiment” means that a particular feature, structure, characteristic, or function described in detail thereby omitting known constructions and functions for clear description of the present invention.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.
In one aspect, provided herein is a process for preparation of a self cushioning automotive fabric.
In another aspect, provided herein is a self cushioning automotive fabric, and a process for preparation thereof in accordance with a preferred embodiment of the present invention.
In a preferred embodiment, the present invention provides a process for preparation of self cushioning automotive fabric, said process comprising the steps of:
a) providing a textile fabric having a first layer (110) of polyurethane;
b) mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents together to form a semi-solid second foam and embedding silver nanoparticles to the semi-solid second foam to form a silver nanoparticle- embedded semi-solid second foam layer (120);
c) applying the silver nanoparticle- embedded second foam layer (120) at a rear side (130) of the first layer (110) by knife over roll coating technology; and
d) curing of the above layer (120) of step c) at a predefined elevated temperature to the obtain solid self cushioning automotive fabric with embedded silver nanoparticles (100).
In this embodiment, the textile fabric having the first layer (110) of polyurethane is formed by mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents together to form a semi solid foam solution; applying said semi solid foam over the rear side (130) of a textile fabric as a first layer and drying said first layer. The drying is carried out at a temperature of 80-110°C. Alternatively, the polyurethane layer is formed on the textile fabric by any of the known method.
The semi-solid second foam is formed by preparing a foam solution by foaming technology. The foam solution is formed by mixing the aqueous polyurethane and foaming agents to form a first mixture. Said mixture is agitated with air to form an even foam solution of about 150 to 300 GPL weight. The second foam is an aqueous and porous layer having micro pores. The foaming agents are selected from the group comprising of alpha olefin sulphonate, surfactant foaming agents, Ammonium stearate, and the like. The fixing agents are non-ionic melamine resin cross linkers. The second foam is a semi-solid layer of polyurethane with the wet GSM range of 450 to 700 gm/m2.
In this embodiment, the semi-solid second foam is embedded with silver nanoparticles comprising the steps of adding a predefined amount of silver nanoparticles in a predefined amount of fixing agents to obtain a silver nanoparticles solution. The silver nanoparticles solution is mixed with the semi-solid second foam to form the silver nanoparticle-embedded semi-solid second foam layer (120). According to an embodiment, the silver nanoparticles are in a range from about 10 parts to about 15 parts. The aqueous solution for preparing the aqueous polyurethane is selected from the group comprising of water, anionic polyurethane binders, and the like. The foam of the present invention is prepared in a foaming machine called as foamer, to create foam by taking pre-defined amount of chemical paste and pressurized air, followed by mixing to achieve desired foam density (gm/ltr volume). In accordance to an embodiment, the aqueous polyurethane solution is in an amount ranging from 800 parts to 1100 parts and the curing temperature is from 80 °C to 150°C.
Further, in this one embodiment, the silver nanoparticle-embedded semi-solid second foam layer (120) is an even thick layer on the rear side (130) of the first layer (110) with better adhesion to fabric, which provides better cushioning by improving compression set throughout the surface by its porous structure and un-creased face fabric surface with retained tactile behaviour of primary fabric surface. The second foam layer (120) absorbs perspiration i.e. higher wicking property and better air permeability. Further, this foam layer is embedded on the fabric surface providing cushioning itself since there is no requirement of applying another foam on the fabric by any other method.
In an embodiment, the first layer (110) is selected from the group comprising of woven fabric, knitted fabric, non-woven fabric and the like.
In an embodiment, the fabric is selected from the group comprising of polyester, cotton, polyamide and/ or their blends, and the like.
In an embodiment, the second foam is selected from the group comprising of polyurethane and the aqueous solution for preparing the aqueous polyurethane is selected from the group comprising of water, anionic polyurethane binders, and the like.
In an embodiment, the foaming agents are selected from the group comprising of alpha olefin sulphonate, surfactant foaming agents, Ammonium stearate and the like.
In an embodiment, the fixing agents are non-ionic melamine resin cross linkers.
In an embodiment, the GSM range of the aqueous and porous foam layer embedded with silver nanoparticles is in a range of about 100 GSM to 500 GSM.
In an embodiment, the aqueous polyurethane solution is in an amount ranging from 800 parts to 1100 parts. The silver nanoparticles are in a range from 10 parts to about 15 parts. The curing temperature is from 80 °C to 150°C. The process as claimed in claim 2, wherein drying is carried out at a temperature of 80-110°C.
In accordance to a preferred embodiment of the present invention, the bilayered automotive fabric has antimicrobial properties. The second foam is applied by aqueous based coating technology and is devoid of isocyanate particles. It is to be noted that in view of absence of isocyanate, the fabric is an eco-friendly product. Also there is no isocyanate fume formation due to aqueous coating and curing technology.
The detailed process for preparation of self-cushioning automotive fabric is described in detail hereinafter:
Referring to FIGS. 1, in an initial step, a textile fabric having a first layer (110) of polyurethane is provided. Next step includes mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents together to form a semi-solid second foam and embedding silver nanoparticles to the semi-solid second foam to form a silver nanoparticle- embedded semi-solid second foam layer (120). This above step of forming silver nanoparticle- embedded semi-solid second foam layer (120) includes providing an aqueous polyurethane solution initially, followed by mixing a predefined amount of aforesaid aqueous polyurethane with a predefined amount of foaming agents together to form a foam solution. In this, next step includes agitating the foam solution with air to form an even foam solution for obtaining a second foam. In this, a further step includes embedding the second foam with silver nanoparticles by adding a predefined amount of silver nanoparticles in a predefined amount of fixing agents to obtain a silver nanoparticle solution, wherein the silver nanoparticles solution is mixed with the semi-solid second foam to form a silver nanoparticle- embedded semi-solid layer (120).
In a next step the above layer (120) is cured at a predefined elevated temperature. Final step includes applying the silver nanoparticle-embedded second foam layer (120) at a rear side (130) of the first layer (110) by knife over roll coating technology to obtain solid self cushioning automotive fabric (100) of the present invention.
The initial step of forming the textile fabric having a first layer (110) of polyurethane comprises the steps of mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents together to form a semi solid foam solution; applying said semi solid foam over rear side of a textile fabric as a first layer and drying the said first layer.
In an embodiment, the present invention provides a self cushioning automotive fabric. The self cushioning automotive fabric is a bilayered fabric comprising:
a textile fabric with a polyurethane as a first layer;
a second foam layer, wherein the second foam is formed by mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents, followed by air agitation, to form a even foam solution for obtaining the second layer; and wherein the second foam being an aqueous porous foam of polyurethane embedded with silver nanoparticles.
Examples
Example 1: Preparation of foam layer formulation.
About 800 to 1100 parts (w/w) aqueous polyurethane matrix was mixed with about 5 to 15 parts (w/w) foaming agents to form an aqueous mixture. The aqueous mixture was further mixed with about 20 to 40 parts (w/w) of fixing agents embedded with 10 to 15 parts (w/w) of nano silver, as anti-microbial agent.
Example 2: Comparative study on the wicking property of the fabric (100) of the present invention.

Table 1
A comparative study on the wicking property of the fabric (100) of the present invention was conducted. The test method followed was AATCC 197, wherein it was observed that the wicking property of the fabric (100) of the present invention (hereinafter,’ invented fabric’) was comparatively improved than the wicking property of the regular fabric. Referring to Table 1 and Figure 2, the fabric (100) of the present invention showed improved wicking of 9cm as compared to the 6 cm wick of the regular fabric.
Example 3: Comparative study on the air permeability of the fabric (100) of the present invention.

A comparative study on the air permeability of the fabric (100) of the present invention was conducted. The test method followed was ASTM D 737, wherein it was observed in Table 1 and Figure 3, that the air permeability of the fabric (100) of the invented fabric was improved to 24.83 cc/sec/cm2 as against the regular fabric with air permeability of 21.36 cc/sec/cm2.
Example 4: Comparative study on the improved compression and anti-microbial property of the fabric (100) of the present invention.

A comparative study on the improved compression and anti-microbial property of the fabric (100) of the present invention was conducted. The test methods followed was ASTM D 1056 and AATCC 6538 respectively. As shown in Table 1 and Figure 4, the compression of the fabric (100) of the invented fabric improved as against the regular fabric. Further, there was 99.10% efficiency of the fabric (100) with respect the anti-microbial property.
In the context of the present invention, the process of preparation of the second foam layer (120) is advantageously located on a rear side (130) of the automotive fabric to provide dimensional stability and a stable structure to the fabric of the present invention. The second foam layer (120) advantageously provides a self cushioning property to the fabric of the present invention. The process for preparation of the self cushioning automotive fabric of the present invention is an ecofriendly process. The process of the present invention is harmless to health and is user friendly as there are no harmful isocyanate fumes generated during as well as after the process. The second porous layer of the fabric with embedded silver nanoparticles of the present invention has antimicrobial properties. The fabric with embedded silver nanoparticles is a porous coating with antimicrobial properties. Porous coating is layer of coating having micro pores and due to the porosity the layer looks bulky similar to foam which is used in general automotive fabric. The fabric (100) of the present invention provides better cushioning by improving compression set throughout the surface by the porous structure of the second layer and un-creased fabric surface of the first layer. The second foam layer of the fabric of the present invention advantageously absorbs perspiration i.e. higher wicking property and provides better air permeability.
The embodiments of the invention shown and discussed herein are merely illustrative of modes of application of the present invention. Reference to details in this discussion is not intended to limit the scope of the claims to these details, or to the figures used to illustrate the invention.
It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.
,CLAIMS:
1. A process for preparation of self cushioning automotive fabric (100), said process comprising the steps of:
a) providing a textile fabric having a first layer (110) of polyurethane;
b) mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents together and embedding silver nanoparticles, to form a silver nanoparticle- embedded semi-solid second foam (120);
c) applying the silver nanoparticle- embedded second foam (120) at a rear side (130) of the first layer (110) by knife over roll coating technology; and
d) curing of the above layer (120) of step c) at a predefined elevated temperature to the obtain solid self cushioning automotive fabric with embedded silver nanoparticles (100).
2. The process as claimed in claim 1, wherein the step of providing the textile fabric having the first layer (110) of polyurethane comprising steps of mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents together to form a semi solid foam solution; applying said semi solid foam over the rear side (130) of a textile fabric as a first layer and drying said first layer.
3. The process as claimed in claim 1, wherein the aqueous polyurethane solution is in an amount ranging from 800 parts to 1100 parts.
4. The process as claimed in claim 1, wherein the semi-solid second foam is embedded with silver nanoparticles comprising the steps of:
a) adding a predefined amount of silver nanoparticles in a predefined amount of fixing agents to obtain a silver nanoparticles solution,
b) the silver nanoparticles solution is mixed with the semi-solid second foam to form the silver nanoparticle-embedded semi-solid second foam (120).
5. The process as claimed in claim 1, wherein the silver nanoparticles are in a range from 10 parts to about 15 parts.
6. The process as claimed in claim 1, wherein the curing temperature is from 80 °C to 150°C.
7. The process as claimed in claim 2, wherein drying is carried out at a temperature of 80-110°C.
8. The process as claimed in claim 1, wherein the foaming agent is selected from alpha olefin sulphonate, surfactant foaming agents, Ammonium stearate.
9. The process as claimed in claim 4, wherein the fixing agents are the non-ionic melamine resin cross linkers.
10. The process as claimed in claim 1, wherein the present invention is devoid of isocyanate particle formation.
11. A self cushioning automotive fabric comprising:
a) a textile fabric with a polyurethane as a first layer;
b) a second foam layer, wherein the second foam layer is formed by mixing a predefined amount of aqueous polyurethane with a predefined amount of foaming agents, followed by air agitation, to form a even foam solution for obtaining the second foam; and wherein
c) the second foam being an aqueous porous foam layer of polyurethane embedded with silver nanoparticles to form second form layer.
12. The self cushioning automotive fabric as claimed in claim 11, wherein the first layer (110) is selected from woven fabric, knitted fabric or non-woven fabric.
13. The self cushioning automotive fabric as claimed in claim 11, wherein the fabric is selected from the group comprising of polyester, cotton, polyamide and/ or their blends.
14. The self cushioning automotive fabric as claimed in claim 11, wherein, the second foam is selected from the group comprising of polyurethane aqueous solution, wherein the aqueous polyurethane is selected from the group comprising of water, anionic polyurethane binders, and the like.
15. The self cushioning automotive fabric as claimed in claim 11, wherein the second foam is a layer of polyurethane with the wet GSM range of 450 to 700 gm/m2.
16. The self cushioning automotive fabric as claimed in claim 11, wherein the silver nanoparticle- embedded second foam layer (120) has a GSM range of 100 GSM to 500 GSM.