OA16580A - Cellulose fibre composition - Google Patents
Cellulose fibre composition Download PDFInfo
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- OA16580A OA16580A OA1201300156 OA16580A OA 16580 A OA16580 A OA 16580A OA 1201300156 OA1201300156 OA 1201300156 OA 16580 A OA16580 A OA 16580A
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- fibres
- length
- composition
- weighted average
- cellulosic
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- 239000000203 mixture Substances 0.000 title claims abstract description 71
- 229920003043 Cellulose fiber Polymers 0.000 title claims description 8
- 239000000835 fiber Substances 0.000 claims abstract description 79
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 29
- 239000000123 paper Substances 0.000 claims description 14
- 238000000227 grinding Methods 0.000 claims description 10
- 240000000218 Cannabis sativa Species 0.000 claims description 8
- 235000009120 camo Nutrition 0.000 claims description 8
- 235000005607 chanvre indien Nutrition 0.000 claims description 8
- 239000011487 hemp Substances 0.000 claims description 8
- 235000012765 hemp Nutrition 0.000 claims description 8
- 235000012766 marijuana Nutrition 0.000 claims description 8
- 239000000843 powder Substances 0.000 claims description 7
- 229920000742 Cotton Polymers 0.000 claims description 6
- 239000002994 raw material Substances 0.000 claims description 6
- 239000002699 waste material Substances 0.000 claims description 6
- 238000001125 extrusion Methods 0.000 claims description 5
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- 241000196324 Embryophyta Species 0.000 claims description 4
- 240000006962 Gossypium hirsutum Species 0.000 claims description 4
- 239000000654 additive Substances 0.000 claims description 4
- 238000007670 refining Methods 0.000 claims description 4
- 238000004078 waterproofing Methods 0.000 claims description 4
- 240000005337 Agave sisalana Species 0.000 claims description 3
- 240000000491 Corchorus aestuans Species 0.000 claims description 3
- 235000011777 Corchorus aestuans Nutrition 0.000 claims description 3
- 235000010862 Corchorus capsularis Nutrition 0.000 claims description 3
- 240000006240 Linum usitatissimum Species 0.000 claims description 3
- 235000004431 Linum usitatissimum Nutrition 0.000 claims description 3
- 240000000907 Musa textilis Species 0.000 claims description 3
- 238000004880 explosion Methods 0.000 claims description 3
- 238000011084 recovery Methods 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 2
- 229920000126 Latex Polymers 0.000 claims description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M NaHCO3 Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 2
- 235000015450 Tilia cordata Nutrition 0.000 claims description 2
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 2
- 238000004040 coloring Methods 0.000 claims description 2
- 239000000975 dye Substances 0.000 claims description 2
- 239000000945 filler Substances 0.000 claims description 2
- 239000003063 flame retardant Substances 0.000 claims description 2
- 239000003292 glue Substances 0.000 claims description 2
- 239000004816 latex Substances 0.000 claims description 2
- 239000004571 lime Substances 0.000 claims description 2
- 239000010447 natron Substances 0.000 claims description 2
- 239000000049 pigment Substances 0.000 claims description 2
- 229920005989 resin Polymers 0.000 claims description 2
- 239000011347 resin Substances 0.000 claims description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N silicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 claims description 2
- 239000001993 wax Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 description 14
- 238000000034 method Methods 0.000 description 10
- 229920002678 cellulose Polymers 0.000 description 9
- 235000010980 cellulose Nutrition 0.000 description 9
- 239000000047 product Substances 0.000 description 9
- 210000001138 Tears Anatomy 0.000 description 7
- 239000001913 cellulose Substances 0.000 description 7
- 206010061592 Cardiac fibrillation Diseases 0.000 description 6
- 238000009826 distribution Methods 0.000 description 6
- 230000002600 fibrillogenic Effects 0.000 description 6
- 239000002657 fibrous material Substances 0.000 description 6
- 238000000465 moulding Methods 0.000 description 6
- 239000010893 paper waste Substances 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- 238000011068 load Methods 0.000 description 5
- 230000002522 swelling Effects 0.000 description 4
- 238000004064 recycling Methods 0.000 description 3
- 238000007792 addition Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 239000012467 final product Substances 0.000 description 2
- 238000001746 injection moulding Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 210000002421 Cell Wall Anatomy 0.000 description 1
- 102100015236 FKBP15 Human genes 0.000 description 1
- 101710005643 FKBP15 Proteins 0.000 description 1
- 229920001410 Microfiber Polymers 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000002596 correlated Effects 0.000 description 1
- 230000000875 corresponding Effects 0.000 description 1
- 229950008597 drug INN Drugs 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000002655 kraft paper Substances 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000003658 microfiber Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
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Abstract
A cellulosic composition comprising fibres having a length weighted average fibre length ("LWAFL") of 0.25 to 0.40 mm.
Description
The disclosure relates to cellulosic compositions that are useful as structural building components for objects including, but not limited to, buildings, furniture, car parts, coffins, cabinets & cases, electronic housing, structural building pillars, beams, boards, sheets, veneers, chairs, musical instruments, and toys.
Large amounts of waste generated in the pulp and paper processing industry are typically disposed to landfill. Disposai to landfill, however, is becoming increasingly problematic due to the environmental constraints associated with land availability and land/soil contamination. As such, there is significant pressure to reduce the amount of waste disposed to landfill, one means of réduction being recycling.
Recycling of paper and textile materials requires the breakdown of such materials into fibres or fibre-like material which may then be reformed into material to provide paper and paper-like products. As an alternative to reforming into material to provide paper and paper-like products, a recycling process has previously been developed for producing moulded pièces out of cellulose fibres in which the spécifie gravity of the moulded pièces approaches that of pure cellulose, 1.5. The process involves finely chopping and grinding cellulose fibres in the presence of water into micro-fibres prior to forming a fibre-water mixture in which the cellulose fibre content is about 1-15% by weight. The process subsequently involves shaping and drying the mixture of cellulose fibres and water into the moulded pièces. Details of the process and the moulded pièces produced by the process are set out in US Patent No. 6,379,594.
- 2 Efforts have continued in the production of cellulosic based compositions derived from pulp and paper processing waste and plant fibres which have high load bearing capacities and the ability for use as structural components.
Summary
The disclosure provides a cellulosic composition comprising fibres having a length weighted average fibre length (LWAFL) of 0.25 to 0.40mm.
Preferably, 0.28 to 0.38mm.
The disclosure also provides a cellulosic composition comprising, by weight:
(a) 15¾ to 25¾ fibres of a length weighted average fibre length of 0.001 mm to 0.2 mm;
(b) 40% to 50% fibres of a length weighted average fibre length of 0.2 mm to 0.5 mm;
(c) 8% to 35% fibres of a length weighted average fibre length of 0.5 mm to 1.2 and (d) less than 3% fibres of a length weighted average fibre length of 1.2 mm to 2.0 mm.
The length weighted average fibre length (LWAFL) provides a measure of the average length of the fibres in a sample of fibres which is weighted by the length of the individual fibres. The LWAFL gives emphasis to the longer fibers in the sample and imparts less emphasis to the shorter fibers and fines. The LWFAFL is sometimes referred to as just the weighted average fibre length or WAFL.
The LWAFL can be compared to other measures of the average length of the fibres in a sample such as the arithmetic or numerical average (AFL) and the weight weighted average fiber length (WWAFL). These averages are obtained through the following calculations:
/1/7, = whcrt;.
N
LWAl-'L =
Σ(/χ ' nà
Σ(/χ w*) <ï = hin »
WWAFL = ·ξ·( /ξ * *x}
Σ(/* · ηύ
I = Inn nitxltnn liingtli n “ bin liber p.iuni N = total number of libers cou ntnd
Preferably, the composition has a Water Rétention Value (WRV) of 600% to 2000%, more preferably, 700% to 1300%.
The water rétention value (WRV) is defined as the amount of water that participâtes in the swelling of the fibrous material and that which is not released under the application of a centrifugal force. The WRV is also highly correlated to the bonding ability of kraft fibers. The test to détermine the WRV is carried out by placing a pad of moist fibers in a centrifuge tube that has a fritted glass filter at its base. The centrifuge is accelerated at 3000g for 15 minutes to remove water from the outside surfaces and lumens of the fiber. The remaining water is believed to be associated with submicroscopic pores within the cell wall. The centrifuged fibers are weighed, dried at 105°C, and then reweighed. The WRV can then be calculated from the ratio of the water mass to the dry mass. The apparatus used to measure the WRV is shown schematically in Figure 1.
In an embodiment, the composition comprises, by weight:
(a) 15% to 25% fibres of a length weighted average fibre length of 0.001 mm to 0.2 mm;
(b) 45% to 55% fibres of an a length weighted average fibre length of 0.2 mm to 0.5 mm;
(c) 20% to about 30% fibres of a length weighted average fibre length of 0.5 mm to 1.2 mm and (d) less than 1% fibres of a length weighted average fibre length of 1.2 mm to 2.0 mm.
The cellulosic composition may be in a wet or dry state.
In an embodiment, the cellulosic composition are dried in the form of pellets, granules or powders. In the dry state, the cellulosic composition may be conveniently stored and transported.
The dry pellets, granules or powders may be mixed with water to form mouidable, fine pulps that may be dried to create materiais for use as structural components.
The mouidable, fine pulps may be moulded using any suitable method including, but not limited to, spray molding, injection molding, extrusion or three stage molding. The moulded or green articles may be subsequently dried to form a product
The density of the product produced from a composition according to the disclosure may be from 0.5 g/cm3 to 1.5 g/cm3. The tensile modulus of the product may be from 3500 MPa to 10800 MPa and the tensile strength may be from 27 MPa to 115 MPa.
Whilst functional additives (such as dyes and pigments for colouring, resins and waxes for waterproofing, lime, fire retardants including natron silicate, glues, métal powders and graphites for electrical conductivity, latex for flex and waterproofing, fillers and very long fibres of 1.5-6.0mm in length for increased tensile strength) may be added to the pulp of dry cellulosic powders/granules/pellets mixed with water, there is no need for the addition of any functional additives or the application of pressure to dry and harden the pulp.
In an embodiment, the composition may be prepared by any one or combination of processing methods including, but not limited to, ultra friction grinding, high pressure homogenizing, cryo grinding, extrusion, steam explosion, ultra sonie treatment, enzyme-fibre séparation, high
- 5 consistency/medium consistency/low consistency refining, chemical treatment or whitewater fines recovery.
Components of the composition may be prepared separately and mixed together. In an embodiment, two or 5 more intermediary compositions with different fibre length distributions may be prepared and mixed in the required proportions to form the compositions defined above.
Various raw materials may be used in the préparation of the compositions as described herein, including, but 10 not limited to, short/ultra short cellulose fibres/fines recovered from waste streams, for example, recovered paper, recovered fines in whitewater from paper & pulp processing and recovered cotton fibers. Additional raw materials may also include any cellulosic fibers used in 15 pulp δ paper processing and various plant fibers having a high cellulosic content, for example, hemp, flax, cotton, abaca, sisal and jute.
The disclosure also provides a product made from a composition as described herein.
Brief description of the Figures
Embodiments will now be described, with reference to the accompanying Figures, in which:
Figure 1 is a schematic view of an apparatus for 25 measuring the Water Rétention Value (WRV) of fibre samples;
Figures 2-6 depict Norval Wilson stained microscope images of wet pulp compositions derived from wastepaper a the scales indicated;
Figure 7 depicts Norval Wilson stained microscope images of wet pulp compositions derived from hemp cellulose at the scales indicated; and
Figures 8-13 are graphs of the fibre length distributions for the wet pulp compositions shown in 35 Figures 2-7.
t
- 6 Detailed Description of the Embodiments
Embodiments provide cellulosic composition made up of fibres having different spécifie lengths, a high degree of fibrillation and a high water rétention capacity· These composition may be subsequently moulded and dried to produce finished wood-like or horn-like articles of high strength and which therefore can be used as load bearing products.
The composition comprise fibres having a length weighted average fibre length (LWAFL) of 0.25 to 0.40mm, preferably 0.28 to 0.38mm. The fibre lengths in the composition are distributed in a skewed bell curve, with the composition comprising, by weight:
(a) 15% to 25% fibres of a length weighted average fibre length of 0.001 mm to 0.2 mm;
(b) 40% to 60% (preferably 45% to 55%) fibres of a length weighted average fibre length of 0.2 mm to 0.5 mm;
(c) 8% to 35% (preferably 20% to 30%) fibres of a length weighted average fibre length of 0.5 mm to 1.2 and (d) less than 3% (preferably less than 1%) fibres of a length weighted average fibre length of 1.2 mm to 2.0 mm.
Thus the composition consists of a significant amount of fines (fibre length <0.2mm) mixed with short length fibres (fibre length of 0.2-1.2mm).
Additionally, the composition has a high degree of fibrillation indicatd by a high Water Rétention Value (WRV) of 600-2000%, preferably, 700-1300%.
The composition is prepared by any one or combination of processing methods including, but not limited to, ultra friction grinding, high pressure homogenizing, cryo grinding, extrusion, steam explosion, ultra sonie treatment, enzyme-fibre séparation, high consistency/medium consistency/iow consistency refining, chemical treatment or whitewater fines recovery.
- Ί Components of the composition may be prepared separateiy and mixed together. In some embodiments, two or more intermediary compositions with different fibre length distributions are prepared and mixed in the required proportions to form the composition.
Various raw materials may be used in the préparation of the composition, including, but not limited to, short/ultra short cellulose fibres/fines recovered from waste streams, for example, recovered paper, recovered fines in whitewater from paper ί pulp processing and recovered cotton fibers. Additional raw materials may also include any cellulosic fibers used in pulp & paper processing and various plant fibers having a high cellulosic content, for example, hemp, flax, cotton, abaca, sisal and jute.
The composition may be dried for transport and/or storage in the form of pellets, granules or powders. From these forms, the compositions may be re-wetted to form moldable, fine pulps. Alternatively, the compositions may 20 be prepared as a pulp and used directly in a molding process. The compositions as a pulp may be moulded by any moulding operations known to persons skilled in the art, for example, spray molding, injection molding, extrusion or three stage molding. The moulded or green articles may 25 be subsequently dried to form a product.
Advantageously, the composition can be used to create a material with appropriate hardness, strength and ductility to be used as a structural material yet remains (as a wet pulp) capable of being readily handled during processing and manufacture of articles from the composition, including very large articles. Furthermore, the composition does not require excessive energy to produce and is therefore economically viable.
Accordingly when molded and dried, the composition can be used to create structural and industrial components such as coffins, electronic housings, structural building t
- 8 pillars, beams, boards, sheets, veneers, boxes, chairs, cabinets, cases and other furniture, car parts and toys.
It will be appreciated that due to a variation in the compositions of the raw materials in terms of, for example, lignin content, ash content, OH bonding capacity and degree of entanglement/fibrillation, as well as the choices of fibre processing parameters, the physicaï properties of the final product produced from the composition will vary. For example, the density may vary from 0.5 to 1.5g/cm3, the tensile modulus may vary from 3500 to 10800MPa and the tensile strength may vary from 27 to llSMPa.
Examples
Fibre furnish and degree of fibrillation
Five samples (A to E) based on waste paper, RCW80 deinked recovered waste paper from Amcor, and one sample (F) based on hemp cellulose, Hempcell B from Celesa in Spain, were subjected to grinding in a high consistency 22 refiner. The fibre (solids) content in the pulp was 16wt% and the flow rate of pulp through the refiner was
| approximately 200L/min. The spécifie energy | (the amount of to the fibre) | ||
| energy transferred | from the refiner's motor of the Samples: | ||
| input was | for each | ||
| Sample A | 1.8kWh/kg | ||
| Sample B | 1.8kWh/kg | ||
| Sample C | 1,8kWh/kg | ||
| Sample D | 1.6kWh/kg | ||
| Sample E | 2.0kWh/kg | ||
| Sample F | 1,9kWh/kg | ||
| The | spécifie | edge load (the amount of | energy applied |
across one meter of refiner plate's bar edge and transferred to the pulp in one second) was between 4-8Ws/m at the beginning of the refining process and this load was
- 9 gradually reduced to between l-4Ws/m by the end of the process.
The fibres were processed until the spread of the average fibre length matched a known bell curve. From expérience and knowing the process inputs, this occurs after a certain time period of processing. However, the fibres may be sampled to confirm that they hâve this distribution of fibre lengths.
A light microscope and a Norval Wilson stain was used on the prepared slides containing dispersed fibre samples and images were taken of each sample as depicted in Figures 2 to 7. As can been seen from these Figures, a high degree of fibrillation is observed for the six samples and most of the fibres were broken or eut into very small fragments.
Suspension properties: morphological properties as well as résistance to déhydration and swelling behaviour
0.2g (dry weight) of each Sample A-F after the grinding process described above were strongly diluted by pre-suspending in water, stirring, and subsequently filling with water to 5000 ml. From this suspension, 25 ml were taken (corresponding to 1.0 mg (dry weight) fibrous material) and photographed. The photographs were subsequently analysed (double détermination) using FibreLab 3.0 equipment to détermine the fibremorphological properties and distribution parameters for the separated and suspended fibres, încluding the fibre length. The results for fibre length are provided in Table 1 below.
I t
- 10 Table 1 - Fibre length
| Sample | Arithmetic Fibre Length (mm) | Length Weighted Average Fibre Length (mm) | Mass Weighted Average Fibre Length (mm) |
| (AFL) | (LWAFL) | (WWAFL) | |
| A | 0.25 | 0.37 | 0.47 |
| B | 0.27 | 0.40 | 0.54 |
| C | 0.26 | 0.39 | 0.49 |
| D | 0.30 | 0.44 | 0.55 |
| E | 0.25 | 0.36 | 0.46 |
| F | 0.20 | 0.29 | 0.41 |
The results in Table 1 show that ail samples (A to F) contain extremely shortened fibres. The arithmetic average of the measured fibre lengths is skewed somewhat by the presence of fines (<0.2mm). This can be mathematically corrected (reduced), by weighting the lengths and masses, ie. by referring to the LFAFL or WWAFL.
In practice the length weighted average fibre length (LFAFL) is typically used for the comparison of fibrous materials with one another. From the values of the LFAFL for ail Samples in Table 1, it can be seen that similar values are obtained for ail Samples based on wastepaper (A to E) with a slightly shorter value for the Sample based on hemp cellulose (F).
The results shown in Table 2 below are an évaluation of the distribution of fibre lengths within certain length ranges. The majority of fibres of ail six Samples (A to F) after processing are 0.2-0.5mm, which is considered to be the short fibre or fibre fragment range. This is also shown graphically in Figures 8-13. Each of these Figures (for respective samples) contains two graphs. The top graph in each of Figures 8-13 shows the distribution of fibres having lengths of <0.06mm whilst the lower graph in each of these Figures shows the distribution of fibres having lengths of >0.1mm.
t
- 11 Table 2 - Distribution of fibre lengths (length weighted average length in length ranges) by weight%
| 0.001- 0.2mm | 0.2- 0.5mm | 0.5- 1.2mm | 1.2- 2.0mm | 2.0- 3.2mm | 3.2- 7.6mm | |
| Sample A | 22.8% | 54.1% | 23.1% | 0.1% | 0.0% | 0.0% |
| Sample B | 19.3% | 51.0% | 29.1% | 0.3% | 0.2% | 0.1% |
| Sample C | 19.1% | 53.11 | 27.8% | 0.0% | 0.0% | 0.0% |
| Sample D | 15.2% | 48.7% | 35.8% | 0.3% | 0.0% | 0.0% |
| Sample E | 22.5% | 55.6% | 21.8% | 0.2% | 0.0% | 0.0% |
| Sample F | 33.2% | 57.2% | 9.3% | 0.2% | 0.1% | 0.0% |
The fines content of the ground samples were investigated further by determining the fraction of the fines (fibres <0.2mm) in each Sample based on the arithmetic average fibre length (AFL). This fraction for each Sample is compared to the length weighted fraction of fines (as per 10 Table 2) is shown in Table 3 below. As can be seen from
Table 3, the fines content of ail Samples (A to F) is very high. The hemp cellulose Sample F, notably contained markedly more fine material than the wastepaper samples (A to E) .
Table 3 - Fine material contents
| Sample | Fine material (<0.2mm) | Fine material (<0.2mm) |
| (arithmetic average) | (length weighted average) | |
| % | % | |
| A | 49.4 | 22.8 |
| B | 45.0 | 19.3 |
| C | 45.7 | 19.1 |
| D | 38.7 | 15.2 |
| E | 47.3 | 22.5 |
| F | 57.3 | 33.2 |
Further measurements of the diameter, wall thickness and calculated (curvature) parameters using the Fibrelab
!
- 12 equipment show that samples A to E derived from wastepaper hâve similar values whereas sample F derived from hemp cellulose has smaller fibre dimensions and a smaller curvature. This resuit corresponds with the fibre lengths 5 determined as well as with the fibre fragments présent.
Table 4 - Further fibre data
| Sample | Fibre width | Fibre wall thickness | Fibre curvature |
| pm | pm | % | |
| A | 16.5 | 3.8 | 17.9 |
| B | 16.2 | 3.8 | 18.1 |
| C | 16.4 | 3.8 | 17.3 |
| D | 17.0 | 4.1 | 19.3 |
| E | 17.0 | 4.0 | 18.0 |
| F | 13.9 | 3.3 | 16.2 |
Détermination of the Water Rétention Capacity (WRC) according to Zellcheming fact sheet IV/33/57
Ail Samples A to F (after grinding described above) were homogenised by mixing prior to sampling for détermination of their Water Rétention Capacity (WRC).
The Samples of fibrous material were dehydrated (to a solids content of approximately 25wt%) on a G2 frit in the absence of a vacuum and transferred to a swell tube (according to DIN 53814) . The swell tube was filled to approximately two-thirds capacity (resulting in a solids content of approximately 0.150wt%). The swell tube was sealed with a plug and subjected to a centrifugal force of 3000g for 15 minutes. Six parallel déterminations were performed.
The water not participating in the swelling of the fibres was removed from the fibrous material by the centrifugation. The swelling water and the water rétention capacity were gravimetrically determined by drying the fibrous material at 105°C until a constant mass solids content was achieved. The results are shown in Table 5.
- 13 Table 5 - Water Rétention Capacity
| Sample | A | B | C | D | E | F | |
| Water Rétention Capacity | o *0 | 841 | 742 | 1532 | 774 | 1138 | 1052 |
The values of the water rétention capacity are extremely high and atypical particularly compared to commercially available, strongly ground celluloses. The higher WRC generally equates to a denser material which when moulded and dried into a final product results in a product which has a lower tear or tensile strength but a higher load io bearing capacity and Young's modulus. A preferred range for Water Rétention Capacity is generally between 700 and 1200% as above this range, the low tear strength makes it difficult to form sheets - as was found with Sample C.
Material properties: physical/strength properties
Samples A to F were ground as described above and mixed with water in a mixer to a solids concentration in the range between 0.3 and 0.4wt% (3 to 4 g/L) as per Table 20 8 below.
Table 8
| Sample | A | B | C | D | E | F | |
| Solids Concentration in the mixer | wt% | 0.367 | 0.379 | 0.351 | 0.379 | 0.354 | 0.351 |
The objective was to produce test sheets with an average grammage of mA of 80+2 g/m2, for use in subséquent strength testing according to the Rapid-Kothen method (in accordance with ISO 5269-2). It is noted that due to the very low déhydration capability of ail of the Samples, the ISO 5269-2 test spécifications had to be adapted by reducing the volume of filling water in the cylinder and varying the period of drop and suction to suit the
- 14 required conditions for sheet forming for each of Samples A to F.
After producing the test sheets for each of the Samples, the test sheets were acclimatised in standard climate conditions (23C°/50% relative air humidity).
The grammage of the acclimatised test sheets was ten determined according to DIN EN ISO 536. The results of the grammage testing are shown in Table 9.
Table 9 - Sample Grammage
| Sample | A | B | C | D | E | F | |
| Grammage | g/m2 | 79.3 | 81.2 | 74.4 | 81.0 | 78.5 | 77.6 |
Due to the characteristics of the materials it was very difficult to produce test sheets with uniform grammage. This was especially the case of sample C wherein the targeted value (80±2 g/m2) could not be realised despite repeated corrections. This is due to the very high Water Rétention Capacity (WRC) of the Samples. In order to compensate for the non-uniformity in grammage between the test sheets, the strength values hâve been corrected with respect to grammage.
The test sheets were subjected to thickness and apparent sheet density testing, the results of which are shown in Table 10.
Table 10 - Sheet thickness and apparent sheet density
| Sample | A | B | C | D | E | F | |
| Thickness | pm | 84 | 88 | 78 | 89 | 80 | 81 |
| Apparent sheet density | g/cm3 | 0.94 | 0.92 | 0.95 | 0.91 | 0.98 | 0.96 |
By virtue of the high proportion of very short, fine fibres, the thickness at the grammage strived for was small and the density very high. This corresponds to the normal behaviour at high packing densities that are achieved with very short fibres.
- 15 The test sheets were subjected to tensile testing according to DIN EN ISO 1924-2, the results of which are shown in Table 11 below.
The values for breaking force, élongation, breaking length and Young's modulus determined from this testing are not corrected with respect to the grammage, but are corrected with respect to the breaking length (represented as the Tensile Index):
Table 11 - Tensile test results
| Sample | A | B | C | D | E | F | |
| Breaking force | N | 81.1 | 85.5 | 71.8 | 84.3 | 74.5 | 77.5 |
| Elongation | % | 3.0 | 3.0 | 2.2 | 3.3 | 2.3 | 3.5 |
| Breaking length | m | 7050 | 7250 | 6500 | 7100 | 6500 | 6700 |
| Tensile Index | Nm/g | 69.1 | 71.0 | 63.7 | 69.7 | 63.7 | 65.9 |
| Young's modulus | GPa | 7.85 | 7.77 | 7.88 | 7.48 | 7.92 | 7.92 |
From the results in Table 11, the tensile strength, expressed as tensile index, corresponds to that of ground cellulose. Whilst the tensile strength values for the Samples differ, there is little variation in the Young's modulus of the Samples which is high. The high Young's modulus of each of the Samples is indicative that the Samples can withstand tensile loads elastically for long periods of time. Without wishing to be bound by theory, it is expected that this is due to the high amount of fibrillation of the fibres and the subséquent linkages between the fibrillated fibres.
The test sheets were eut into strips and subjected to tear résistance testing according to DIN EN 21974, The results are shown in Table 12. The résistance to tearing is not corrected according to the grammage, only according to the tear index.
- 16 Table 12 - Tear Résistance
| Sample | A | B | C | D | E | F | |
| Tear résistance (E) | mN | 222 | 280 | 181 | 294 | 195 | 215 |
| Tear index | Mn m’/g | 2.67 | 3.41 | 2.46 | 3.62 | 2.55 | 2.80 |
The tearing strength of ail samples, measured on standard celluloses, is at a very low level, i.e. the résistance to tear is low. This can be attributed primarily to very short fibres.
In the claim which follows and in the preceding description, except where the context requires otherwise due to express Ianguage or necessary implication, the word comprise or variations such as comprises or comprising is used in an inclusive sense, ie. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments.
It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms part of the common general knowledge in the art, in Australia or any other country.
Claims (16)
- CLAIMS:1. À cellulosic composition comprising fibres having a length weighted average fibre length (LWAFL) of 0.25 to 0.40mm.
- 2. A cellulosic composition as claimed in claim 1, the composition comprising, by weight:(a) 15% to 25% fibres of a length weighted average fibre length of 0.001 mm to 0.2 mm;(b) 40% to 60% fibres of a length weighted average fibre length of 0.2 mm to 0.5 mm;(c) 8% to 35% fibres of a length weighted average fibre length of 0.5 mm to 1.2 and (d) less than 3% fibres of a length weighted average fibre length of 1.2 mm to 2.0 mm.
- 3. A cellulosic composition comprising, by weight:(a) 15% to 25% fibres of a length weighted average fibre length of 0.001 mm to 0.2 mm;(b) 40% to 60% fibres of a length weighted average fibre length of 0.2 mm to 0.5 mm;(c) 8% to 35% fibres of a length weighted average fibre length of 0.5 mm to 1.2 and (d) less than 3% fibres of a length weighted average fibre length of 1.2 mm to 2.0 mm.
- 4. A cellulosic composition as claimed in any one of the preceding claims, wherein the composition has a Water Rétention Value (WRV) of 600% to 2000%.
- 5. A cellulosic composition as claimed in any one of the preceding claims, wherein the composition comprises, by weight:(a) 15% to 25% fibres of a length weighted average fibre length of 0.001 mm to 0.2 mm;(b) 45% to 55% fibres of an a length weighted average fibre length of 0.2 mm to 0.5 mm;(c) 20% to about 30% fibres of a length weighted average fibre length of 0.5 mm to 1.2 mm and (d) less than 1% fibres of a length weighted average fibre length of 1.2 mm to 2.0 mm.
- 6. A cellulosic composition as claimed in any one of the preceding claims, wherein the cellulosic composition is in the form of pellets, granules or powder.
- 7. A cellulosic composition as claimed in any one of the preceding claims, wherein the composition also comprises one or more functional additives.
- 8. A cellulosic composition as claimed in claim 7, wherein the functional additives are selected from dyes and pigments for colouring, resins and waxes for waterproofing, lime, fire retardants including natron, silicate, glues, métal powders and graphites for electrical conductivity, latex for flex and waterproofing, fillers and very long fibres of 1.5-6.0mm in length for increased tensile strength^
- 9. A cellulosic composition as claimed in any one of the preceding claims, wherein the composition is prepared by any one or combination of processing methods including ultra friction grinding, high pressure homogenizing, cryo grinding, extrusion, steam explosion, ultra sonie treatment, enzyme-fibre séparation, high consistency/medium consistency/low consistency refining, chemical treatment or whitewater fines recovery.
- 10. A cellulosic composition as claimed in any one of the preceding claims, wherein components of the composition are prepared separately and mixed together.t
- 11. A cellulosic composition as claimed in claim 10, wherein two or more intermediary compositions with different fibre length distributions are prepared and mixed in the required proportions to form the composition.
- 12. A cellulosic composition as claimed in any one of the preceding ciaims, wherein the raw material used in the préparation of the compositions comprises one or more of short/ultra short cellulose fibres/fines recovered from îo waste streams, recovered paper, recovered fines in whitewater from paper & pulp processing and recovered cotton fibres, any cellulosic fibres used in pulp & paper processing and plant fibres having a high cellulosic content such as hemp, flax, cotton, abaca, sisal and jute.
- 13. A product made from a composition as claimed in any one of the preceding ciaims..
- 14. A product as claimed in claim 13, wherein the density 20 of the product is from 0.5 g/cm3 to 1.5 g/cm3.
- 15. A product as claimed in claim 13 or 14, wherein the tensile modulus of the product is from 3500 MPa to 10800 MPa.
- 16. A product as claimed in any one of ciaims 13-15, wherein the tensile strength of the product is from 27 MPa to 115 MPa.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2010904775 | 2010-10-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| OA16580A true OA16580A (en) | 2015-11-20 |
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