FORM-2
THE PATENT ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(see section 10 and rule 13)
MODIFIED POLYESTER FIBRES
RELIANCE INDUSTRIES LIMITED
an Indian organization of 3rd Floor, Maker Chamber-IV 222, Nariman Point, Mumbai-400021,
Maharashtra, India.
Inventors:
1. GAJELLI Chandramouli Gangaram
2. KELKAR Anil Krishna
3. GURUDATT Krishnamurthy
4. SREEKUMARThaliyilVeedu
5. NIKAM Suresh Bhanudas
6. BHANGALE Vikas Kadu
7. ARORA Arun
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

FIELD OF THE DISCLOSURE:
The present disclosure relates to surface modified polyester fibres and a process for preparing the same. The present disclosure also relates to a polyester cementitious product comprising surface modified polyester fibres and a process for preparing the polyester cementitious product.
BACKGROUND:
Natural fibres are used in cement because of their dispersing capacity in cement slurry to form webs and binding ability with cement.
For example, cellulosic fibres are used in the manufacture of autoclaved fibre-cement sheets which require high temperatures (around 180°C) and high pressures (around lObar). These autoclaved sheets are preferred over air-cured sheets because of higher strength and dimensional stability.
However, the cellulosic fibres used in the cement are sourced from nature and there is strain on the nature resoruces.
Therefore, there exists a need for a product that replaces natural fibres for economic reasons and simultaneously provides binding strength to the cementitious products.
Accordingly, the inventors of the present invention provide surface modified polyester fibres which can be utilized in the cement and concrete material as a secondary reinforcement component.
OBJECTS:
Some of the objects of the present disclosure which at least one embodiment is adapted to provide, are described herein below:
It is an object of the present disclosure to provide surface modified polyester fibres.
It is another object of the present disclosure to provide surface modified polyester fibres having improved binding-ability with cementitious material.

It is still another object of the present disclosure to provide surface modified polyester fibres capable of imparting flexural strength to a product derived from cementitious material.
It is further object of the present disclosure to provide a process for preparing surface modified polyester fibres.
It is still further object of the present disclosure to provide polyester modified cementitious product having improved flexural strength.
It is still farther object of the present disclosure to provide a process for preparing polyester modified cementitious product having improved flexural strength.
Other objects and advantages of the present disclosure will be more apparent from the following description.
SUMMARY:
In accordance with one aspect of the present disclosure there is provided surface modified polyester fibres comprising fibres of at least one polyester coated with at least one surface modifier.
Typically, the ratio of the polyester to the surface modifier in the surface modified polyester fibres ranges from 1:0.1 to 1:0.5.
Typically, the surface modified polyester is capable of imparting flexural strength to a product derived from cementitious material.
Typically, the surface modifier is at least one chemical selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes.
Typically, the styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer, styrene ethyl acrylate copolymer.

Typically, the water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide.
In accordance with the another aspect of the present disclosure there is provided a process for preparing surface modified polyester fibres, said process comprising the following steps:
i. treating fibres of at least one polyester with at least one surfactant to obtain a treated polyester fibres; and
ii. modifying the surface of the treated polyester fibre with at least one surface modifier by using at least one technique selected from the group consisting of spraying, dipping, impregnating, applying, brushing, painting, blowing, pouring and contacting followed by drying to obtain the surface modified polyester fibres having the ratio of the polyester to the surface modifier from 1:0.1 to 1:0.5.
Typically, the surface modifier is at least one chemical selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes.
Typically, the styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer, styrene ethyl acrylate copolymer.
Typically, the water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide.
In accordance with still another aspect of the present disclosure there is provided a polyester modified cementitious product comprising:
i. at least one cementitious material in an amount ranging from 50.0 wt%
to 60.0 wt%; ii. silica in an amount ranging from 30.0 wt% to 40.0 wt%;

iii. cellulose in an amount ranging from 3.0 wt% to 6.0 wt%; and iv. surface modified polyester fibres in an amount ranging from 0.1 wt% to 1.0 wt%; said surface modified polyester fibres comprising fibres of at least one polyester coated with at least one surface modifier, wherein said surface modified polyester is capable of imparting flexural strength to said cementitious product and the ratio of the polyester to the surface modifier ranges from 1:0.1 to 1:0.5.
Typically, the surface modifier is at least one chemical selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes.
Typically, the styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer, styrene ethyl acrylate copolymer.
Typically, the water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide.
In accordance with further aspect of the present disclosure there is provided a process for preparing a polyester modified cementitious product, said process comprising the following step:
a. obtaining a composition comprising;
i. at least one cementitious material in an amount ranging from 50.0 wt% to 60.0 wt%;
ii. silica in an amount ranging from 30.0 wt% to 40.0 wt%;
iii. cellulose in an amount ranging from 3.0 wt% to 6.0 wt%;
iv. a surface modified polyester in an amount ranging from 0.1 wt% to 1.0 wt%; said surface modified polyester comprises fibres of at least one polyester coated with at least one surface modifier

having the ratio of the polyester to the surface modifier from 1:0.1 to 1:0.5,
b. molding said composition into a product; and
c. curing said product by autoclaving at pre-determined temperature and pressure
parameters to obtain the polyester modified cementitious product.
DETAILED DESCRIPTION:
Cellulosic fibres are being used as reinforcement of cement and cementitious products for high temperature auto-clave applications. However, cellulose fibres being natural fibres are draining the natural resources as they being made from wood pulp. Hence, synthetic polyester fibres are being explored for this purpose. However, polyester fibres have lower binding ability with cement as compared to natural fibres. Therefore, they cannot be used in cement applications. To make polyester fibres compatible for applications in cement the inventors of the present invention modified the surface of polyester fibre. The surface of the polyester is modified by coating fibres of polyester with at least one surface modifier. The fibres to be surface modified can be of one or more polyester. The inventors of the present disclosure found that the surface modified polyester imparts enhanced flexural strength to a product in which it is used.
The surface modifier, which facilitates fibre-cementitious material adhesion and curing of cementitious material, is at least one chemical selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes. Examples of acrylate polymer include styrene-butyl acrylate copolymer and styrene-ethyl acrylate copolymer. Epoxides, useful for the purpose of the present invention include glycerol epoxide, sorbitol epoxide and combination thereof.
The process by which the surface modified polyester fibres of the present disclosure are prepared is described herein after.

In the first step, fibres of at least one polyester are treated with at least one surfactant known to a person skilled in the art to obtain treated polyester fibres. The treated polyester fibres are then subjected to surface modification using at least one technique one technique selected from the group consisting of spraying, dipping, impregnating, applying, brushing, painting, blowing, pouring and contacting to obtain the surface modified polyester fibres. The ratio of the polyester to the surface modifier in the surface modified polyester fibres obtained according to the process of the present disclosure ranges from 1:0.1 to 1:0.5.
The surface modified polyester fibres of the present disclosure have improved binding-ability to cementitious material at high temperatures and pressures and are capable of imparting flexural strength to a product in which it is used. The amount of the surface modified polyesters fibres of the present disclosure in the product in which it is used plays a considerable role in obtaining the desired result.
Accordingly, after series of experiments the following polyester modified cementitious product was found to provide the desired properties:
i. at least one cementitious material in an amount ranging from 50.0 wt% to 60.0 wt%;
ii. silica in an amount ranging from 30.0 wt% to 40.0 wt%;
iii. cellulose in an amount ranging from 3.0 wt% to 6.0 wt%; and
iv. surface modified polyester fibres in an amount ranging from 0.1 wt% to 1.0 wt%; said surface modified polyester fibres comprising fibres of at least one polyester coated with at least one surface modifier, wherein said surface modified polyester is capable of imparting flexural strength to said cementitious product and the ratio of the polyester to the surface modifier ranges from 1:0.1 to 1:0.5.
The process for preparing the polyester modified cemetitious product is also provided in the present disclosure. The first step for preparing polyester modified cemetitious product is to obtain a composition comprising at least one cementitious material in an amount ranging from 50.0 wt% to 60.0 wt%; silica in an amount ranging from 30.0

wt% to 40.0 wt%; cellulose in an amount ranging from 3.0 wt% to 6.0 wt%; surface modified polyester fibres in an amount ranging from 0.1 wt% to 1.0 wt%. The surface modified polyester fibres used for obtaining the polyester modified cemetitious product comprises fibres of at least one polyester coated with at least one surface modifier and are capable of imparting flexural strength to the cementitious product and the ratio of the polyester to the surface modifier ranges from 1:0.1 to 1:0.5.
The obtained composition is then molded into a desired product and cured by autoclaving at pre-determined temperature and pressure parameters to obtain the polyester modified cementitious product.
The invention will now be described with the help of the following non-limiting examples.
Example 1:
Step A: Preparation of surface modified polyester
0.5 gm of 1.5d, 6mm polyester fibres were treated with 0.5 gm of non-ionic surfactant blend of castor oil ethoxylates and then coated with 0.15 gm of styrene-acrylate copolymer by spraying technique.
Step B: Preparation of sheets
0.5 gm of surface modified polyester obtained in step A was mixed with 94.2 gm of cement, 62.8 gm of silica. 7.5 gm of cellulose to obtain a composition. The composition is then molded into sheets which were then autoclaved at 180 °C and 8 bar pressure to obtain sheets containing surface modified polyester.
Example 2:
Step A: Preparation of surface modified polyester
0.5 gm of 1.5d, 6mm polyester fibres were treated with 0.5 gm of non-ionic surfactant blend of castor oil ethoxylates and then coated with 0.15 gm of vinyl acetate polymer by spraying technique.

Step B: Preparation of sheets
0.5 gm of surface modified polyester obtained in step A was mixed with 94.2 gm of cement, 62.8 gm of silica, 7.5 gm of cellulose to obtain a composition. The composition is then molded into sheets which were then autoclaved at 180 °C and 8 bar pressure to obtain sheets containing surface modified polyester.
Comparative Example 1:
Step A: Preparation of sheets
9.9 gm of cellulose was mixed with 93.1 gm of cement, 62.0 gm of silica to obtain a composition. The composition is then molded into sheets which were then autoclaved at 180 oC and 8 bar pressure to obtain sheets.
The flexural strength of the sheets obtained in Examples 1 and 2 were compared with sheets obtained in comparative example 1. The results are provided in table 1 below:
Table 1: Comparative results of flexural strength of sheets of Examples 1 and 2 and comparative example 1

Sr. No. Particulars Flexural strength (kg/cm2) in MRA
I Sheets of comparative example 1 50.6
2 Sheets of example 1 63.3
3 Sheets of example 2 62.1
TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE
The polyester fibres of the present invention provide improved binding ability with cementitious material.

The embodiments as described herein above, and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the description. Descriptions of well-known components and . processing techniques are omitted so as to not unnecessarily obscure the embodiments herein.
The foregoing description of specific embodiments will so fully reveal the general nature of the embodiment herein, that others can, by applying current knowledge, readily modify and/or adapt for various applications of such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein. Further, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
Having described and illustrated the principles of the present disclosure with reference to the described embodiments, it will be recognized that the described embodiments can be modified in arrangement and detail without departing from the scope of such principles. Without departing from the scope of this invention all standard processing additives can be used in any of the embodiment.
Many modifications of the present disclosure will be apparent to those skilled in the art to which the present disclosure applies. Further, it may be desirable to use some of the above-described features without the corresponding use of other features. Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

WE CLAIM:
1. Surface modified polyester fibers comprising fibers of at least one polyester coated with least one surface modifier.
2. The surface modified polyester fibers as claimed in claim 1, wherein the ratio of the polyester to the surface modifier ranges from 1:0.1 to 1:0.5.
3. The surface modified polyester fibers as claimed in claim 1, wherein said surface modified polyester is capable of imparting flexural strength to a product derived from cementitious material.
4. The surface modified polyester fibers as claimed in claim 1, wherein the surface modifier is at least one chemical selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes.
5. The surface modified polyester fibers as claimed in claim 4, wherein the styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer, styrene ethyl acrylate copolymer.
6. The surface modified polyester fibers as claimed in claim 4, wherein the water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide.
7. A process for preparing surface modified polyester fibers as claimed in claim 1, said process comprising the following steps:
i. treating fibers of at least one polyester with at least one surfactant to obtain a treated polyester fibers; and

ii. modifying the surface of the treated polyester fiber with at least one surface modifier by using at least one technique selected from the group consisting of spraying, dipping, impregnating, applying brushing, painting, blowing, pouring and contacting followed by drying to obtain the surface modified polyester fibers having the ratio of the polyester to the surface modifier from 1:0.1 to 1:0.5.
8. The process as claimed in claim 7, wherein the surface modifier is at least one chemical selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes.
9. The process as claimed in claim 8, wherein the styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer, styrene ethyl acrylate copolymer.
10. The process as claimed in claim 8, wherein the water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide.
11. A polyester modified cementitious product comprising:
i. at least one cementitious material in an amount ranging from 50.0
wt% to 60.0 wt%; ii. silica in an amount ranging from 30.0 wt% to 40.0 wt%; iii. cellulose in an amount ranging from 3.0 wt% to 6.0 wt%; and iv. surface modified polyester fibers in an amount ranging from 0.1
wt% to 1.0 wt%; said surface modified polyester fibers

comprising fibers of at least one polyester coated with at least one surface modifier, wherein said surface modified polyester is capable of imparting flexural strength to said cementitious product and the ratio of the polyester to the surface modifier ranges from 1:0.1 to 1:0.5.
12. The polyester modified cementitious product as claimed in claim 11, wherein the surface modifier is at least one chemical selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes.
13. The polyester modified cementitious product as claimed in claim 12, wherein the styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer, styrene ethyl acrylate copolymer.
14. The polyester modified cementitious product as claimed in claim 12, wherein the water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide.
15. A process for preparing a polyester modified cementitious product, said process comprising the following step:
a. obtaining a composition comprising;
i. at least one cementitious material in an amount ranging from
50.0 wt% to 60.0 wt%; ii. silica in an amount ranging from 30.0 wt% to 40.0 wt%; iii. cellulose in an amount ranging from 3.0 wt% to 6.0 wt%;

iv. a surface modified polyester in an amount ranging from 0.1 wt% to 1.0 wt%; said surface modified polyester comprises fibers of at least one polyester coated with at least one surface modifier having the ratio of the polyester to the surface modifier from 1:0.1 to 1:0.5,
b. molding said composition into a product; and
c. curing said product by autoclaving at pre-determined temperature and
pressure parameters to obtain the polyester modified cementitious product.