Title of Invention

"A PROCESS FOR THE MANUFACTURE OF HIGH STRENGTH PAPER FROM BAMBOO PULP"

Abstract A process for the manufacture of high strength paper from bamboo comprising in the steps of: i) preparing bamboo pulp from bamboo chips by the known method of kraft cooking; ii) subjecting such a pulp 1o single, double and third stage of fractionation as herein described to obtain a pulp containing enriched quantity of long fibres; iii) mixing said fractionated pulp with a waste pulp, such as double sorted old corrugated container having long fibres and then; iv) manufacturing the paper from the mixed pulp by a known method, characterized by the step of fractionation of Bamboo pulp wherein single step fractionation comprises feeding the bamboo pulp/feed to the fractionator with the basket of 0.35 mm hole at a pressure of 2-2.2 kg/cm2 and at a consistency of 2.8-3%, short fraction received through the accept side of the fractionator screen and the long fraction of the pulp from the reject side of the fractionator screen, the long fraction are further subjected to double and third stage of fractionation after dilution with water.
Full Text FIELD OF INVENTION
This invention relates to a method of
manufacture of high strength paper from tropical raw material such as bamboo pulp.
PRIOR ART
The copies of pulp from soft wood for
manufacture of high strength paper is recognised in the art, as softwood contains long fibers which imparts the
high strength properties of paper. Thus, high strength paper such as extensible sack paper used in specially
packaging, wrapping and other applications is mainly manufactured from pulp made of softwoods fibre such as
pine and spruce or softwood mixed with double sorted old corrugated containers (DSOCC). The incorporation of
DSOCC pulp in the aforesaid pulp mixture is in order to reduce the costs, Typically 40% softwood and 60% DSOCC
pulp is used for making extensible sack paper in Indian paper mills. The pulps required for manufacture of high
strength paper from softwood and DSOCC determined from hand-sheets made at 25°SR (schapper reigler) generally
have the following properties.
(Table Removed)
However, hard wood and non-wood raw materials are not suitable for manufacturing high strength paper due to insufficient quantity of long fibres in the pulp obtained from such raw material.
Bamboo which is abundantly available in the tropical region, has reasonably high proportion of long
fibre fraction. Pulp obtained from bamboo contains about 35-40% long fibre fraction which is retained on +14/+28 mesh of Bauer McNett fibre classifier. The average fibre length of this long fibre bamboo fraction is 3.0 to 3.5 mm. Thus the long fibre fraction of bamboo pulp has the requisite physical strength properties suitable for manufacture of high strength paper.
OBJECTS OF THE INVENTION
The main object of this invention is to propose a method for manufacture of high strength paper such as extensible sack by using tropical raw material such as bamboo.
Another object of this invention is to separate the long fibre fraction of bamboo kraft pulp for obtaining pulp of requisite quality for manufacture of high stength paper.
BRIEF DESCRIPTION OF THE INVENTION
According to this invention there is provided a process for the manufacture of high strength paper from bamboo comprising in the steps of:
i) preparing bamboo pulp from bamboo chips by the known method of kraft cooking;
ii) subjecting such a pulp to single, double and third stage of fractionation as herein described to obtain a pulp containing enriched quantity of long fibres;
iii) mixing said fractionated pulp with a waste pulp, such as double sorted old corrugated container having long fibres and then;
iv) manufacturing the paper from the mixed pulp by a known method, characterised by the step of fractionation of Bamboo pulp wherein single step fractionation comprises feeding the bamboo pulp/feed to the fractionator with the basket of 0.35 mm hole at a pressure of 2-2.2 kg/cm2 and at a consistency of 2.8-3%, short fraction received through the accept side of the fractionator screen and the long fraction of the pulp from the reject side of the fractionator screen, the long fraction are further subjected to double and third stage of fractionation after dilution with water.
In accordance with the present invention the method of manufacturing high strength paper with the bamboo pulp includes the step of separation of long fibre fraction from bamboo pulp through a fractionation process. The fractionation process involves fractionation of bamboo pulp through one, two or more successive stages, depending upon the size of the fibre required to be obtained. The bamboo or mixed pulp is
fed to the fractionator at a controlled consistency. Other process parameters such as feed rate, reject rate
and the operating pressure are also kept under control to separate the short fraction as an accept from the
fractionator screen and the long fraction of the pulp is withdrawn from the reject side of the fractionator
screen.
The long fraction so obtained from the
reject side of the first stage fractionation can be subjected to further fractionation after dilution with
water, if required, to obtain desired quality of long fibre fraction. The fractionation process described
above can be repeated further, depending on the requirement.
According to an option the short fibre
obtained from accept side of the fractionator screen can be recycled to maximize the recovery of long fibre
fraction.
The long fraction (LF2) of bamboo pulp
received after second/double stage of fractionation are mixed with double sorted old corrugated contains (DSOCC)
in the percentage as 70-80% LF2 with 20-30% DSOCC or any other such fibre. Similarly (long fraction) LF3
received after third stage of fractionation are mixed as follows:-
00.55 - 607. by weight of LF3 with 40 - 45% DSOCC
Though fractionation is known but
fractionation Bamboo fibre under the proposed condition is not known which is for yielding high strength fibre
suitable for high strength paper.
The process parameters for single stage and
double stage fractionation are maintained as follows:— Single stage fractionation
Screen with 0.35 mm slots
Pressure,kg/cm2 Consistency ,7.
First stage, feed 2-2.2 2.8-3
First stage,short fraction 1.2-1.8 1.8-2 First stage,long fraction — 4—4.5
Double stage fractionation Basket with 1.2 mm dia round holes in first stage and
0.35 mm slots in the second stage.
Pressure,kg/cm2 Consistency ,X
First stage, feed 0.9-1.2 2.8-3.2(preferably 3.0)
First stage,short 0.7-0.9 1.7-1.9(preferably 1.8)
fraction (Preferably .8)
First stage,long fraction - 4-5
Second stage, feed 1.3—1.7 2.5—3.5
Second stage, short 0.7-0.9 1.6-1.95 fraction
Second stage, long - 4-5 (preferably 4.5)
fraction
After second fractionation long fibre in the pulp increases by approximately 20%, breaking length by
1700 to 2100 meter, stretch by 0.7 to 0.9 percent, tear factor by 30-37 points and TEA (Tensile Energy
Absorption) by 25 to 30 J/m2. Air resistance of long fibre fraction is reduced by 40—50X.
Illrd STAGE FRACTIONATION
Basket with 1.2 mm diameter round hole basket in first stage 0.35 mm slot in the second stage and .25 mm slot in the Illrd stage.
Pressure, kg /cm Consistency,%
First stage, feed 0.9-1.2 2.8-3.2 (preferably
3.0)
First stage,short 0.6-0.9 1.8-2.2 (preferably 2%)
fraction (preferably .8)
First stage,long fraction - 4-5 (preferably 4.5) Second stage, feed 1.3—1.8 2.5—3.5
Second stage, short 0.6-0.9 1.8-2.2(preferably 2.0) fraction
Second stage, long — 4—5(preferably 4.0)
fraction
Third stage, feed 1-1.5 2.5-3.5
Third stage, short 0.6-0.9 2-2.2(Preferably
fraction 2.1)
Third stage, long — 4—5
fraction
After 3rd stage fractionation long fibre in the pulp increases by approximately 22-24%, breaking length by 2200 to 2300 meter, stretch by 1 to 1.1%, tear factor by 35-40 points and (Tensile Energy Absorption) by 50 to 54 J/m2. Air resistance of long fibre fraction is reduced by 40—50%.
A method of manufacture of high strength paper from bamboo pulp according to a preferred embodiment is herein described in detail and is examplified in the following.
EXAMPLE
12.623 metric ton bamboo pulp was processed per
hour through a first stage fractionator with the basket of 1.2 mm hole at pressure of 1 kg/cm2 and
at a consistency of 3%. This was resulted in a first stage short fraction at a pressure ,8kg/cm2 and
at a consistency of 27. with the pulp yield of 5.049 ton per hour. Also first stage long fiber was obtain
at a consistency of 4.5% with yield of 7.574 m ton per hour.
The first stage long fiber pulp after diluting
with water was fed to second stage fractionator of 0.35mm slot at a pressure of 1.5 kg/cm2 at a
constitency of 2.9%. This resulted in second stage of short fibre of 3.408 m ton per hour at a pressure
of 0.8 kg/cm2 at a consistency of 2%. It also resulted in second stage long fibre generation of
4.166 meter ton per hour at a consistency of 4.5%
The second stage long fibre fraction was passed through a third stage fractionator of 0.25 mm slot basket after dilution to a consistency of
2.9% at feed pressure of 1.2 kg/cm2. This resulted in generation of IIIrd stage short fibre of 2.083 m
ton/per hour at a consistency of 2.1% and at a pressure of 0.7 kg/cm2. The third stage long
fibre generation was 2.0S3 m. ton per hour at a consistency of 4.6%.







WE CLAIM;
1. A process for the manufacture of high strength paper from bamboo
comprising in the steps of:
i) preparing bamboo pulp from bamboo chips by the known method of kraft cooking;
ii) subjecting such a pulp to single, double and third stage of fractionation as herein described to obtain a pulp containing enriched quantity of long fibres;
iii) mixing said fractionated pulp with a waste pulp, such as double sorted old corrugated container having long fibres and then;
iv) manufacturing the paper from the mixed pulp by a known method, characterised by the step of fractionation of Bamboo pulp wherein single step fractionation comprises feeding the bamboo pulp/feed to the fractionator with the basket of 0.35 mm hole at a pressure of 2-2.2 kg/cm2 and at a consistency of 2.8-3%, short fraction received through the accept side of the fractionator screen and the long fraction of the pulp from the reject side of the fractionator screen, the long fraction are further subjected to double and third stage of fractionation after dilution with water.
2. A process as claimed in claim 1 wherein first step of double stage
fractionation comprises passing the pulp/feed through a basket of 1.2
mm diameter round holes at a feed pressure of 0.9-1.2 kg/cm2 and at
a consistency of 2.8-3.2%.
3. A process as claimed in claim 2 wherein the reject/long fractions of
the said first step of double stage fractionation is passed through a
0.35 mm slot basket at a feed pressure of 1.3- 1.7 kg/cm2 and
consistency 2.5-3.5% which constitute the second stage.
4. A process as claimed in claim 3, wherein 70-80% long fibres (LF2)
received after double stage fractionation are mixed with 20-30%
double sorted old corrugated containers (DSOCC).
5. A process as claimed in claim 1, wherein the first step of three
stage/step fractionation comprises passing the pulp through a basket
of 1.2 mm dia hole at a pressure of 0.9-1.2 kg/cm2 at a consistency of
2.5-3.5%.
6. A process as claimed in claim 5, wherein the reject/long fibres of said
first step of three stage fractionation are passed through a 0.35 mm
slots at the pressure of 1.3-1.8 kg/cm2 and the consistency of 2.5-
3.5% in the second step fractionation.
7. A process as claimed in claim 6, wherein the reject of said second step
of three stage fractionation is passed through a slot of 0.25 mm at the
pressure of 1-1.5 kg/cm2 and 2.5-3.5 consistency in the third step
fractionation.
8. A process as claimed in claim 7, wherein 55-60% by weight of Long
Fractions (received after third stage fractionation) are mixed with
40-45% by weight of double sorted old corrugated container.
9. A process for the manufacture of high strength paper from bamboo substantially as herein described illustrated.



Documents:

3024-del-1998-abstract.pdf

3024-del-1998-claims.pdf

3024-del-1998-correspondence-others.pdf

3024-del-1998-correspondence-po.pdf

3024-del-1998-description (complete).pdf

3024-del-1998-form-1.pdf

3024-del-1998-form-19.pdf

3024-del-1998-form-2.pdf

3024-del-1998-form-3.pdf

3024-del-1998-form-5.pdf

3024-del-1998-gpa.pdf


Patent Number 215107
Indian Patent Application Number 3024/DEL/1998
PG Journal Number 10/2008
Publication Date 07-Mar-2008
Grant Date 21-Feb-2008
Date of Filing 14-Oct-1998
Name of Patentee BALLARPUR INDUSTRIES LTD.
Applicant Address THAPER HOUSE, 124 JANPATH, NEW DELHI-110001
Inventors:
# Inventor's Name Inventor's Address
1 SUBHASH CHANDER PARUTHI BALLARPUR INDUSTRIES LTD. THAPER HOUSE, 124 JANPATH, NEW DELHI-110001
2 MR. RAJIV VEDERAH BALLARPUR INDUSTRIES LTD. THAPER HOUSE, 124 JANPATH, NEW DELHI-110001
3 RAGHAVAN VARDHAN BALLARPUR INDUSTRIES LTD. THAPER HOUSE, 124 JANPATH, NEW DELHI-110001
4 SUBHASH CHANRA SHENUY BALLARPUR INDUSTRIES LTD. THAPER HOUSE, 124 JANPATH, NEW DELHI-110001
PCT International Classification Number D21F 11/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA