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. |
---|
3024-del-1998-correspondence-others.pdf
3024-del-1998-correspondence-po.pdf
3024-del-1998-description (complete).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:
|
||||||||||||||||
PCT International Classification Number | D21F 11/00 | |||||||||||||||
PCT International Application Number | N/A | |||||||||||||||
PCT International Filing date | ||||||||||||||||
PCT Conventions:
|