Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – With chemical or physical modification of liberated fiber
Reexamination Certificate
2001-08-16
2004-11-30
Fortuna, José A. (Department: 1731)
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
With chemical or physical modification of liberated fiber
C162S157600, C162S109000, C008S181000, C008S189000
Reexamination Certificate
active
06824645
ABSTRACT:
The present invention relates to oxidized cellulose-containing fibrous materials and products obtainable therefrom. These particularly include planar products such as papers or nonwovens. A particularly preferred aspect of the invention relates to tissue papers and tissue products made of such cellulose-containing fibrous materials characterized by advantageous properties, particularly regarding their strength and behavior with respect to moisture that acts from outside. The invention also makes available a method of producing the oxidized fibrous materials and the products derived therefrom.
Planar products which include cellulose-containing fibrous materials according to the invention or which are made therefrom may be present in various forms and are also designated in correspondingly varied ways: for example, the German term “Vlies” (=mat or nonwoven) is used in different ways in German-speaking countries (cf. in this respect:
Handbuch der Papier
-
und Pappenfabrikation
(
Papierlexikon
), second edition, Vol. II, 1971, p. 1997: ISBN 3 500 16 000 X). In the technical language employed by paper makers, the above term is used for the moist fibrous mat which is formed from an aqueous fibrous-material suspension during sheet making upon simultaneous drainage on a screen or between two revolving endless screens. This is then referred to as a moist fibrous mat, the initially formed moist sheet or in the case of an industrial paper machine, as the initially formed, still moist paper web. In the case of higher dry contents, the terms sheet, paper sheet or web and/or paper web are more common.
The German terms “Vlies” and “Vliesstoffe” are also applied to a wide range of products which in terms of their properties are located between the groups of paper, cardboard, board on the one hand and the textile products on the other and are nowadays summarized under the term “nonwovens” (see ISO 9092-EN29092). As regards the production of nonwovens, a large number of extremely varied production processes is used, such as the so-called air-laid and spun-laid techniques, as well as so-called wet-laid techniques, the former as a typical choice from the so-called dry-laid techniques predominating by far and the wet-laid techniques similar to paper manufacturing forming more a marginal group.
Today, the nonwovens are understood as an independent group of products. Nonwovens include mats, nonwoven fabrics and finished products made therefrom, in many cases for hygiene requirements. These composite materials, which frequently resemble textiles, represent flexible porous fabrics that are not produced by the classic methods of weaving warp and weft or by looping, but by intertwining and/or by cohesive and/or adhesive bonding of typical synthetic textile fibers which may for example be present in the form of endless threads or threads prefabricated with an endless length, as synthetic threads produced in situ or in the form of staple fibers. Alternatively, they may be made of blends of synthetic fibers in the form of staple fibers and natural fibers, e.g. natural vegetable fibers (see DIN 61 210 T2 of October 1988 and ISO 9092-EN 29092).
“Papers” are also planar materials, albeit essentially composed of fibers of a vegetable origin and formed by drainage of a fibrous-material suspension on a screen or between two endless revolving screens and by subsequent compression and drainage or drying of the thus produced mat (cf. DIN 6730, May 1996). The standard restricts the range of mass per unit area (basis weight) for paper to less than/equal to 225 g/m
2
.
In German standard DIN 6730, the German term “Karton” (=cardboard) has a definition similar to paper, though the basis weight range extends from 150 g/m
2
to 600 g/m
2
, i.e. there is an overlap here with respect to paper. The term Karton is common only in German-speaking countries.
The German term “Pappe” (=(paper)board) is defined in DIN 6730 as a generic term for solid board and corrugated fibre board and encompasses products in the basis weight range above 225 g/m
2
.
Based on the underlying compatibility of the production processes (wet laying), “tissue” production is counted among the paper making techniques. The production of tissue, or more accurately, raw tissue if the one-ply (intermediate) product manufactured on a special-purpose paper machine of the tissue or tissue paper machine is meant, is delimited from paper production as a result of the extremely low basis weight of normally less than 65, more often less than 40 g/m
2
and as a result of the much higher tensile energy absorption index. The tensile energy absorption index is arrived at from the tensile energy absorption in which the tensile energy absorption is related to the test sample volume before inspection (length, width, thickness of sample between the clamps before tensile load). Paper and tissue paper also differ in general, as do tissue papers which differ from the raw material, chemical additives and production conditions with regard to the modulus of elasticity that characterizes the stress-strain properties of these planar products as a material parameter.
A tissue's high tensile energy absorption index results from the outer or “inner” creping. The former is produced by compression of the paper web adhering to a drying cylinder as a result of the action of a crepe doctor or in the latter instance as a result of a difference in speed between two fabrics. In the latter technique, often referred to as “(wet) rush transfer”, for instance the forming fabric of the paper machine is moved at greater speed than the fabric the formed paper web is transferred to, for instance a transfer fabric or a TAD fabric (through air drying), so that the paper web is bundled somewhat when it is taken up by the transfer fabric. This causes the still moist, plastically deformable paper web to be internally broken up by compression and shearing, thereby rendering it more stretchable under load than paper which has not been subjected to outer or inner creping. Many prior art documents (e.g. EP-A-0 617 164, WO-94/28244, US-5 607 551, EP-A-0 677 612, WO-96/09435) mean this “inner creping”, if they describe the production of “uncreped” tissue paper by rush transfer techniques.
Most of the functional properties typical of tissue and tissue products result from the high tensile energy absorption (see DIN EN 12625-4 and DIN EN 12625-5).
An example of papers and paper products is represented by hygiene papers, particularly tissue papers and hygiene products (tissue products) made therefrom and which are e.g. used in personal grooming and hygiene, the household sector, industry, the institutional field in a wide variety of cleaning processes. They are used to absorb fluids, for decorative purposes, for packaging or even as supporting material, as is common for example in medical practices or in hospitals. In terms of their wide variety, hygiene products are now considered to be everyday products.
Hygiene paper primarily includes all kinds of dry-creped tissue paper, as well as wet-creped paper and cellulose or pulp wadding.
The one-ply intermediate products originating from the paper machine and made of lightweight paper usually dry-creped on a yankee cylinder by means of a crepe doctor are generally described as “tissue paper” or more accurately raw tissue paper. The one-ply raw tissue may be built up of one or a plurality of layers respectively.
All one-ply or multi-ply final products made of raw tissue and tailored to the end user's needs, i.e. fabricated with a wide variety of requirements in mind, are known as “tissue products”.
Typical properties of tissue paper include the ready ability to absorb tensile stress energy, their drapability, good textile-like flexibility, properties which are frequently referred to as bulk softness, a high surface softness, a high specific volume with a perceptible thickness, as high a liquid absorbency as possible and, depending on the application, a suitable wet and dry strength as well as an interesting visual appearance of the ou
Besemer Arie Cornelis
Bragd Petter
Gunnars Susanna
Jaschinski Thomas
Jetten Jan Matthijs
Fortuna Jos'e A.
SCA Hygiene Products GmbH
LandOfFree
Oxidized cellulose-containing fibrous materials and products... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Oxidized cellulose-containing fibrous materials and products..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Oxidized cellulose-containing fibrous materials and products... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3343039