Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/22—Addition to the formed paper
  • D21H23/24—Addition to the formed paper during paper manufacture
  • D21H23/26—Addition to the formed paper during paper manufacture by selecting point of addition or moisture content of the paper
  • D21H23/28—Addition before the dryer section, e.g. at the wet end or press section
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
  • D21H25/02—Chemical or biochemical treatment
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H15/00—Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution
  • D21H15/02—Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution characterised by configuration
  • D21H15/06—Long fibres, i.e. fibres exceeding the upper length limit of conventional paper-making fibres; Filaments
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/10—Coatings without pigments
  • D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
  • D21H19/20—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds

Definitions

• the present invention relates to a process for reinforcing a hydro-entangled pulp fibre material, and to a reinforced hydro-entangled pulp fibre material which has been subjected to the process.
• the reinforced hydro-entangled pulp fibre material is particularly well suited for conversion into industrial wipes, but can be utilised in many other applications which require a relatively inexpensive, textile-like nonwoven material with high absorption capacity for water, organic solvents, oil and grease, high dry and wet strength, low dry and wet linting, and low stiffness.
• Hydro-entangled nonwoven materials can be used in a variety of applications, e.g. for industrial wipes, baby diapers, sanitary napkins, data diskette liners, etc..
• a low degree of lint release is required in many of the applications where hydro- entangled nonwoven materials are utilised.
• the water-jet treatment in the hydro- entangling process removes some loose fibres and debris.
• the presently available hydro-entangled nonwoven materials still may exhibit a lint release level which is higher than desired, either in a dry state (dry linting) or in a wet state (wet linting), or both. This problem is particularly pronounced when hydro-entangled non-woven materials containing pulp fibres are concerned.
• EP 0 411 752 Al describes a method for hydro-entangling a nonwoven fibrous sheet material to significantly increase the strength thereof at low latex add-on values which employs small diameter jets of high-pressure water in the form of coherent streams that concentrate the hydraulic energy over a distance equal to approximately the diameter of the fibres being entangled.
• a relatively low pressure is employed for the fibre rearrangement along with a synergistic effect of wood pulp and long polyester fibres coupled with small amounts of latex to achieve the unexpectedly high strengths within these light weight materials.
• the latex binder generally an acrylic latex binder, is applied onto the fibrous web after drying, e.g.
• the resultant sheet material possesses excellent uniformity of fibre distribution and improved strength characteristics over those typically obtained from prior art water jet entanglement processes requiring 300-2000% the entanglement energy employed in the described process.
• U.S. Patent No. 6,103,061 describes a method of making a nonwoven composite material.
• the method includes the steps of providing a hydraulically entangled web containing a fibrous component and a nonwoven layer of substantially continuous filaments, applying a bonding material to at least one side of said web, and creping said at least one side of the hydraulically entangled web.
• the bonder material may be an aqueous mixture including a curable latex polymer, a pigment and a cure promoter.
• the bonding material may be a conventional adhesive such as e.g. an acrylate, a vinyl acetate, a vinyl chloride, or a methacrylate type adhesive.
• the binder material may for example be applied to cover from about 10% to about 60%, desirably from about 20% to about 40%, of the surface area of each side of the fabric.
• EP 0 538 971 A2 discloses a nonwoven liner for a diskette cartridge which is made of hydro-entangled fibres and impregnated with a small amount of binder which is uniformly distributed throughout the fabric.
• the binder comprises no more than 5% by weight and preferably between 1.5 - 3.0 % by weight of the fabric, wherein it is claimed that the low concentration of binder ensures that the liner surface does not become totally coated with plastic film that reduces cleaning ability, but still provides improvements in tensile strength and debris reduction and ensures a low risk of chemical attack of the disk media surface.
• the fabric is produced from staple length fibres which typically have a denier in the range of 0,5-6 and a length of a half inch to several inches.
• the hydro-entangled fabric is claimed to clean the disk media more efficiently, to have less fibre debris, to contain less environmental contaminants, to be substantially loftier, and to be cut with cleaner edges that standard thermally bonded diskette liners.
• the low concentration of binder provides unexpected gains in strength, debris reduction, flexural rigidity, and a dramatic increase of the dimensional stability measured as force to elongate by 1%, i.e. an increased tensile stiffness.
• EP 0 530 113 Bl describes a continuous process for producing a spunlace non- woven cotton fabric, which consists in advancing a non-woven cotton fibre fabric, interlacing these fibres by means of a plurality of pressurized water jets, drying the interlaced fabric, and finally collecting the obtained fabric.
• the process further includes to drain the free water contained in the interlaced fabric, after interlacing and before drying, and to impregnate the drained fabric by using an aqueous solution of a polyamide-amine-epichlorohydrine resin in an amount of 0.2 % to 1%, measured as dry solids, of the weight of the cotton fibers and, after having expelled the excess solution, to dry the impregnated fabric, at a temperature sufficient to at least initiate the cross-linking of the deposited PAE-resin.
• hydro-entangled nonwoven materials exhibit a relatively low linting level.
• these materials are constituted primarily or exclusively of expensive raw materials such as long staple fibres or synthetic filaments, or long natural fibres, such as cotton, ramie, flax, etc..
• Wood pulp fibres e.g. originating from a chemical or chemi-thermomechanical pulping process, can be used in hydro-entangled nonwoven materials together with longer fibres, e.g. staple fibres or long natural fibres.
• Pulp is a much cheaper raw material than long manmade or natural fibres, but contains a lot of fine material, so-called fines. Consequently, an addition of pulp fibres will increase the linting level and especially the wet linting of a hydro-entangled nonwoven material, usually resulting in a wet linting level which is 5 - 10 times higher than the wet linting level of a hydro-entangled nonwoven material without any pulp fibres.
• the linting level of a hydro-entangled nonwoven material can be reduced by means of a suitable chemical binder, e. g. a so-called latex binder.
• a suitable chemical binder e. g. a so-called latex binder.
• the methods described in the prior art exhibit certain disadvantages.
• One such disadvantage is that the methods according to prior art usually incorporate the chemical binder in the form of a discontinuous surface pattern.
• Such a discontinuous surface pattern results in a higher risk of linting since there will be a larger number of unbonded fibres and fine particles, and a very high total add-on of chemical binder will be required in order to get a sufficient reduction of the linting level or a sufficient linting reduction will be impossible.
• Such a high content of chemical binder will influence the absorption properties of the hydro-entangled nonwoven material adversely and increase the material stiffness, something which is unacceptable for many applications, e. g. industrial wipes.
• hydro-entangled nonwoven materials can be impregnated with polyamide-amine-epichlorohydrine resin (PAE) in order to improve the durability in a wet state.
• PAE polyamide-amine-epichlorohydrine resin
• Hydro-entangled nonwoven materials containing PAE-resin will require a comparatively long curing time, sometimes several weeks and preferably at a temperature higher than room temperature, in order to reach the desired high wet strength level. This Is impractical and increases the production cost, and the wet linting reduction is often insufficient.
• a first object of the present invention is to provide a process for reinforcing a hydro-entangled pulp fibre material which eliminates the above- described problems associated with the prior art, including the problem with additional storage time for curing, and which enables production of a hydro- entangled nonwoven material which is constituted primarily of pulp fibres, but which still exhibits a very low linting level and the desired open and textile-like fibre structure and low stiffness level.
• this first object is achieved by means of a process according to claim 1, including the steps of: mixing pulp fibres, including pulp fines, and water in order to form a fibre suspension; dewatering the fibre suspension in order to form a precursor web; hydro-entangling the precursor web at a maximum water-jet pressure higher than 85 bar in order to remove a majority of the pulp fines and create an open fibre structure after the hydro-entangling; and drying the hydro-entangled precursor web in order to form the hydro-entangled fibre material; and further including the steps of: introducing reinforcement fibres, having a fibre length above 5 mm, into the process, in order to give the hydro-entangled precursor web a dry solids content of the reinforcement fibres which is lower than the dry solids content of the pulp fibres and pulp fines; and introducing a copolymer dispersion acting as a chemical binder into the process.
• a small amount from about 0.5 to about 10 g/m 2 dry solids of the copolymer dispersion is applied onto the precursor web after the hydro-entangling but before the drying, wherein the copolymer dispersion is applied as a substantially continuous coating onto the precursor web being in a wet state enabling the copolymer dispersion to migrate in a z-direction in order to become uniformly distributed throughout the web after the drying, and the small amount and the uniform distribution result in a reinforced fibre network capable of binding and retaining a majority of the pulp fibres and any remaining pulp fines within the reinforced hydro-entangled pulp fibre material while maintaining a low material stiffness.
• a second object of the present invention is to provide a reinforced hydro-entangled pulp fibre material, which can be produced at a relatively low raw material cost, and which exhibits an open fibre structure and excellent absorption properties at the same time as it exhibits a very low linting level and a low material stiffness.
• this second object is achieved by means of a reinforced hydro-entangled pulp fibre material according to claim 17, which material has been subjected to a process according to the invention, and which exhibits a basis weight between 50 and 120 g/m 2 , a wet linting value which is lower than 30 particles/cm 2 when measured as released lint particles/cm 2 in a Biaxial Shake Linting Test, and a tensile stiffness index /MD X CD which is lower than 260 Nm/g.
• Fig. 1 is a schematic representation of a four-roii offset gravure roll coater 1 which can be used in a preferred embodiment of the process according to the invention.
• the process according to the invention is intended for reinforcing a hydro-entangled pulp fibre material.
• "reinforcing” should be understood as making stronger and/or more elastic and/or more durable and/or less linting in comparison to a web containing 100 % pulp fibres.
• the process includes the step of mixing pulp fibres, including pulp fines, and water in order to form a fibre suspension.
• This process step can be performed with raw materials, equipment and process settings which are well known to the skilled person.
• the process further includes the step of dewatering the fibre suspension in order to form a precursor web. Also this process step can be performed with equipment and process settings which are well known to the skilled person.
• the process includes the step of hydro-entangling the precursor web at a maximum water-jet pressure higher than 85 bar in order to remove a majority of the pulp fines and create an open fibre structure after the hydro-entangling. Also this process step is well known to the skilled person. However, as discussed above, this type of high pressure hydro-entanglement process will create "pores" or channels through the fibre structure which are necessary for achieving the desired physical material properties and which in a process according to prior art, but not in the process according to the invention, will Increase the risk of a high wet linting level of the finished material.
• the process further includes the step of drying the hydro-entangled precursor web in order to form the hydro-entangled fibre material.
• the drying can be performed in any suitable dryer, but is preferably performed in a through-drying unit of the type which is wellknown to the skilled person.
• the process further includes the step of introducing reinforcement fibres, having a fibre length above 5 mm, into the process, in order to give the hydro-entangled precursor web a dry solids content of the reinforcement fibres which is lower than the dry solids content of the pulp fibres and pulp fines.
• the reinforcement fibres are mixed with the pulp fibres and pulp fines in order to form the above-mentioned fibre suspension which subsequently is dewatered in order to form the precursor web which is to be hydro-entangled.
• the reinforcement fibres are introduced in another way, e.g. as continuous filaments, or as a separately formed, second precursor web which is hydro-entangled together with the above-mentioned, first precursor web.
• the process includes the step of introducing a copolymer dispersion acting as a chemical binder into the process.
• a small amount from about 0.5 to about 10 g/m 2 dry solids of the copolymer dispersion is applied onto the precursor web after the hydro-entangling but before the drying.
• the copolymer dispersion is applied as a substantially continuous coating onto the precursor web while the precursor web is in a wet state enabling the copolymer dispersion to migrate in a z-direction in order to become uniformly distributed throughout the web after the drying.
• the small amount and the uniform distribution result in a reinforced fibre network capable of binding and retaining a majority of the pulp fibres and any remaining pulp fines within the reinforced hydro- entangled pulp fibre material while maintaining a low material stiffness.
• the small amount of copolymer dispersion is between 0.5 and 3.6 g/m 2 , when calculated as dry solids (DS) of copolymer dispersion / square meter of reinforced hydro- entangled pulp fibre material.
• DS dry solids
• the dry solids content of the precursor web is between 20 and 30 % when applying the smali amount of copoiymer dispersion between the hydro-entangling and the drying.
• the copolymer dispersion is applied directly after the hydro-entanglement step.
• the process further includes a dewatering treatment between the hydro-entanglement and the drying, wherein the dewatering treatment can be accomplished e.g. by means of a suction device.
• the dry solids content of the precursor web is between 30 and 70 %, and preferably between 45 and 55 %, when applying the small amount of copolymer dispersion between the dewatering treatment and the drying.
• the copolymer dispersion is applied in the form of an aqueous dispersion having a dry content between 25 and 60 %, preferably about 50%.
• the copolymer dispersion can be constituted of a number of different polymer combinations and can be provided in the form of various dispersions. However, the copolymer dispersion preferably is applied in the form of a vinyl acetate-ethylene copolymer dispersion.
• This embodiment enables the production of a reinforced hydro-entangled pulp fibre material which exhibits a very low wet linting level at a very low add-on of copolymer dispersion.
• the introduction of the small amount of copoiymer dispersion into the process most advantageously results in a wet linting of the reinforced hydro-entangled pulp fibre material which, measured as released lint particles/cm 2 in a Biaxial Shake Linting Test, is reduced to less than 10 %, and preferably to less than 5%, of the wet linting of an otherwise similar hydro- entangled pulp fibre material but which has been reinforced with the reinforcement fibres only.
• This very dramatic reduction of the wet linting makes the process excellent for production of reinforced hydro-entangled pulp fibre material intended for industrial wipes.
• the introduction of the copolymer dispersion into the process most advantageously results in a tensile stiffness index VMD x CD of the reinforced hydro-entangled pulp fibre material which is increased less than 30 % in comparison to a hydro-entangled pulp fibre material which has been reinforced with the reinforcement fibres only.
• This relatively small stiffness increase means that this embodiment can be used for production of reinforced hydro-entangled pulp fibre materials which are to be used in applications requiring a high level of material flexibility and softness.
• the reinforced fibre network is maintained substantially intact after the drying by means of minimizing friction against any stationary surfaces in the process and in a subsequent converting into a finished product.
• This minimized friction can be achieved e.g. by means of eliminating any stationary surfaces such as creping doctor blades or the like, and by means of selecting converting machinery which uses rotary machine elements only.
• the process includes a wetforming unit.
• the wet- forming unit can be of any suitable type as long as its capable of handling the relatively long reinforcement fibres and of producing a fibre formation which is sufficiently uniform for the subsequent hydro-entanglement.
• a foam surfactant is added to the fibre suspension before the dewatering, and the process includes a foamforming unit.
• the hydro-entanglement and drying are performed inline.
• the hydro-entangling is performed with water-jet pressures ranging between 90 and 130 bar, and advantageously at a machine speed exceeding 45 m/min, and preferably exceeding 100 m/min.
• the copolymer dispersion is applied in the form of an aqueous dispersion by means of an offset gravure roll coater, e.g. of the type which is commercially available from Paper Converting Machine Company (PCMC), Green Bay, Wisconsin, U.S.A.
• PCMC Paper Converting Machine Company
• the copolymer dispersion is applied by means of another suitable equipment, e. g. by means of a spraying equipment.
• a reinforced hydro-entangled pulp fibre material which has been subjected to a process according to the invention will be described in greater detail.
• the material exhibits a basis weight between 50 and 120 g/m 2 , a wet linting value which is lower than 30 particles/cm 2 when measured as released lint particles/cm 2 in a Biaxial Shake Linting Test, and a tensile stiffness index /MD X CD which is lower than 260 Nm/g.
• This unique combination of material properties i.e. a high pulp fibre content, an open fibre structure, and a low wet linting at a relatively low tensile stiffness level, makes the reinforced hydro- entangled pulp fibre material according to the invention very well suited for use in industrial wipes.
• the reinforced hydro-entangled pulp fibre material exhibits a wet linting value which is lower than 10 particles/cm 2 when measured as released lint particles/cm 2 in a Biaxial Shake Linting Test.
• this very low linting level has only been reached by hydro-entangled nonwoven materials without any pulp fibres, i.e. materials which only can be produced at a relatively high raw material cost.
• the material exhibits a tensile stiffness index MD X CD which is lower than 210 Nm/g. This relatively low tensile stiffness level makes the material suitable also for applications where a high material flexibility and softness are required.
• the reinforced hydro-entangled pulp fibre material contains between 0.4 and 12 weight-% dry solids of the copolymer dispersion, and more advantageously between 0.8 and 4 weight-%. In the preferred embodiment, the reinforced hydro-entangled pulp fibre material contains between 1.0 and 3.0 weight-% dry solids of the copolymer dispersion. As will be appreciated by the skiiied person reading this description, the content of copolymer dispersion wiii be minimized for each particular case, while taking the required level of physical properties into consideration (e.g. the wet linting level).
• the material contains a vinyl acetate-ethyl ene copolymer dispersion.
• the reinforced hydro-entangled pulp fibre material according to the invention preferably contains between 51 and 75 weight-% of pulp fibres.
• the pulp fibres included in the material are preferably unbleached or bleached softwood or hardwood pulp fibres originating from a chemical or chemi-thermomechanical pulping process.
• the reinforced hydro-entangled pulp fibre material preferably contains between 20 and 45 weight-% of reinforcement fibres.
• the reinforcement fibres preferably include manmade staple fibres, between 0.4 and 2.5 dtex, made from synthetic or natural polymers. However, it is also conceivable with embodiments where other reinforcement fibres are included, e.g. staple fibres with other dimensions or continuous filaments of suitable polymers.
• the reinforcement fibres include polyethylene, polypropylene (PP), polyester (PET), polyamide, viscose or lyocell fibres, or splitfibres made from these polymers.
• PP polypropylene
• PET polyester
• polyamide polyamide
• viscose or lyocell fibres or splitfibres made from these polymers.
• the reinforcement fibres include natural fibres from cotton, flax, hemp, ramie, milkweed, or other natural fibres exhibiting a fibre length between 5 and 30 mm.
• This embodiment provides a reinforced hydro-entangled pulp fibre material with a higher degree of biodegradability.
• the reinforced hydro- entangled pulp fibre material includes between 54 and 62 weight-% bleached softwood sulphate pulp fibres, between 21 and 29 weight-% PET-fibres, between 13 and 21 weight-% PP-fibres, and between 1,8 and 2,6 weight-% dry solids of vinyl acetate-ethylene copolymer dispersion, wherein the PET- and PP-fibres exhibit fibre dimensions within a range of 1.5 - 1.9 dtex and 15 - 25 mm.
• E-TOR Strong manufactured by SCA Hygiene Products AB
• E-TORK Strong is produced by means of hydro- entangling a precursor web consisting of a mixture of bleached softwood sulphate pulp fibres, polyester staple fibres, and polypropylene staple fibres.
• the pulp fibre content in the finished nonwoven material is higher than 55 weight-%.
• the remaining nonwoven web material was coated in the offset gravure roll coater with different pick-up levels of an aqueous copolymer dispersion, Dur-O-Set Elite 20 ® supplied by Vinamul Polymers (Vinamul DSE-20).
• the dry solids content of the dispersion was 50%.
• the copolymer dispersion was applied onto the nonwoven webs by means of a 440 mm wide, four-roll offset gravure roll pilot coater 1, as illustrated in Fig. 1.
• the copolymer dispersion (not shown) is circulated through a doctor blade chamber 2 in connection with a rotating gravure roll 3.
• the gravure roll 3 picks up copolymer dispersion from the doctor blade chamber and transfers the copolymer dispersion to the offset roll 4.
• the nonwoven web 5 is gently pressed between the pair of offset rolls 4, 4', and in the press nip 6 the copolymer dispersion is transferred onto both sides of the nonwoven web.
• peripheral surfaces of the gravure roiis 3, 3' are engraved with a continuous and very fine pattern in order to produce substantially continuous coating films which can be transferred to the offset rolls 4, 4' and onto both sides of the nonwoven web 5.
• a substantially continuous coating across both web faces will be the most favourable for reducing the linting of the coated nonwoven material.
• the gravure roll speed was set to 10, 20 and 50% of the offset roll speed.
• samples of the different nonwoven materials were dried in an oven at 130 °C for 5 minutes.
• the applied coating weights, or pick-up levels, were determined by means of comparing the basis weights before and after coating treatment.
• Table 1 below shows results from wet linting measurements on the different samples.
• the measurements were performed on dried nonwoven material samples by means of a method called "Biaxial Shake Linting". This method is based on Standard Test Method 1ST 160:2 (95) (Aqueous Method for Determining Release of Particulates) and is suitable for determining the linting level of nonwoven materials in a wet state.
• a 110 x 160 mm test specimen is cut from the nonwoven material which is to be tested, wherein the longer side of the test specimen corresponds to the machine direction (MD).
• a thoroughly rinsed plastic container is filled with 800 ml of demineralised water, and the test specimen is placed at the bottom of the container below the water surface.
• the cap of the plastic container is screwed on, and the plastic container is placed on a biaxial shaking table where it is subjected to shaking for 5 minutes, with a shake setting of 4.5.
• the test specimen is iifted above the water surface by means of a pair of tweezers and water may pour off for approx. 10 seconds before the test specimen is lifted out of the plastic container.
• two 50 ml water samples are extracted in two glass beakers. Fibres and particles
• the copolymer dispersion had a 50% dry solids content when it was applied onto the nonwoven material. This high dry content of the copolymer dispersion is advantageous since it reduces the volume requirements in the coating section, and also since less water has to be evaporated in the dryer.
• the present inventors believe that one reason for this dramatic effect is that the material in a dry state absorbs the water in the copolymer dispersion very rapidly which results in a poor wetting and an non-uniform distribution of the copolymer dispersion on the fibre surfaces and particularly in the z-direction of the material, whereas the material which is in a wet state when treated allows a much better wetting with copolymer dispersion resulting in a very uniform distribution of the copolymer dispersion throughout the fibre structure and also in the z-direction.
• Table 2 is a summary of the results from the laboratory testing of physical material properties performed on the samples from the above-discussed pilot trials.
• Basis weight was measured by means of determining the weight of a test specimen having a known surface area.
• Thickness was measured by means of a conventional thickness meter working at a pressure of 2 kPA.
• Tensile strengths, drv and in water, and stretch were measured by means of a commercially available tensile testing equipment: LLoyd Instruments model LRX, Ametek Test and Calibration Instruments, Foreham, Hampshire, England.
• the test specimens were 50 x 100 mm, the clamping length 100 mm, the tensioning rate 100 mm/min.
• Relative strength in water was calculated from the formula: ( ⁇ (tensile MD * CD, water)/ ⁇ (tensile MD * CD, dry)) * 100%

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• Biochemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Nonwoven Fabrics (AREA)
• Reinforced Plastic Materials (AREA)

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• 2004
  • 2004-11-23 WO PCT/SE2004/001705 patent/WO2005061772A1/en not_active Application Discontinuation
  • 2004-11-23 BR BRPI0417441-0A patent/BRPI0417441A/pt not_active Application Discontinuation
  • 2004-11-23 EP EP04820695A patent/EP1699960A1/en not_active Withdrawn

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