SA01220106A - Polymeric polycarboxylie acid crosslinked cellulosic fibers - Google Patents

Abstract

Cellulosic fibers intertwined from the inside of the fiber are detected with a polymerized polyacrylic acid tangle. In one embodiment, the polymerized polycarboxylic acid is polyacrylic acid, and in another embodiment, the polycarboxylic acid is polyalic acid. Methods are also detected to form cellulosic fibers with stable intracellular fibers and to form crosslinked cellulose fibers with a low contract level.

Description

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Crosslinked Cellulosic Fibers with Polycarboxylic Acid Full Description BACKGROUND The present invention relates generally to crosslinked cellulosic fibers and more particularly to crosslinked cellulosic fibers with polymerized polycarboxylic acid crosslinking agents; Methods of producing these fibers and absorbent formations that contain fibers crosslinked with a polymerized polycarboxylic acid. In general, cellulose fibers are intertwined to give distinctive properties (Fie) increased absorption capacity, large size, and rebound ability for formations that contain cellulose fibers. The fibers of large size are generally more intertwined and characterized by high absorption capacity and high ability to rebound. Its preparation is widely known, Tersoro and willard, Cellulose and Cellulose Derivatives, Bikales and Segal, ed., part v, Wiley — Interscience, New York, (1971), PP. 835 — 875. Crosslinked cellulose fibre" refers to a cellulose fiber with crosslinks within the fiber, i.e. linking individual cellulose chains through one cellulose fibre. Generally, crosslinks are formed within the fiber by treating the crosslinking agent by fermentation or aging in the presence of fibers. The expression 'treatment with fermentation or aging' refers to Formation of a covalent bond (i.e. crosslinking) between the crosslinking agent and the fiber.In general, crosslinking agents are compounds with a dual function, and in the subject of cellulose crosslinking, these agents covalently couple a hydroxy group of a cellulose chain with another hydroxy group in an adjacent cellulose chain. H. Several crosslinking agents are used to crosslink cellulose resulting in varying degrees of success.

v Ordinary cellulose crosslinking agents include aldehyde and urease-based formaldehyde-adding products Los LA See, for example, US Patent Nos. Their suitability for use as absorbent products in contact with human skin (eg diapers) is limited in terms of safety. These crosslinking materials are known to cause irritation to human skin. © In addition, the formaldehyde that remains from crosslinked formaldehyde products is

EPA is known to be dangerous to health and has been registered in the list of substances that cause cancer by, and thus the defects associated with the crosslinking agents of formaldehyde and other formaldehyde derivatives prompted the finding of alternatives that are safe.

Cy and other aldehyde crosslinking agents are known eg die aldehyde crosslinking agents (E0 in the production of sorbent compositions containing Lad dialdehydes and preferably glutaraldehyde) are used - Cg 1831148 on crosslinked cellulose fibres. See eg US Patent Nos. While these crosslinking die-aldehydes overcome the health risks associated with LEAYY SOT formaldehyde as a crosslinker; These crosslinking agents suffer from chemical defects related to the formation of crosslinked dialdehyde fibers. 0 Cellulose is also crosslinked with carboxylic acid crosslinking agents. Poly acids are used

Gl carboxylic acids are specially formulated to provide absorbent formations in which a polycarboxylic acid reacts with in the form of crosslinks within the fiber eg US Patent No. ©, Crosslinking Polycarboxylic Acids Jal se f/a/177© 0132015 Use ©0077 These are -© and ©007 polycarboxylic acids of low molecular weight which contain from © 00 to 4 carbon atoms in the chain or at least 1 at least three carboxylic groups and have a bea ring separating two groups of the carboxyl groups. For example, tetra-4' 7 0 contains tricarboxypropane, polycarboxylic YO- and ©-0: Ali.

carboxy (liam) and oxydisuccinic acid. The Cy - Co polycarboxylic acid of particular preference is 7-hydroxy-0; 1,7-tricarboxypropane; Mans Lind defines citric. Aldehyde-based crosslinking agents noted Undesirability is high; these polycarboxylic acids are non-toxic and citric acid is a preferred polycarboxylic acid; 0 crosslinking agent is commercially available at a relatively low price.Furthermore, while aldehyde-based crosslinking agents form relatively unstable acetal crosslinks, crosslinking agents A polycarboxylic acid, Cy -©: esters give relatively stable bonding.While some of the disadvantages related to the above-mentioned crosslinking agents have been overcome by the development and use of new and developed crosslinking agents, the crosslinking agents are generally characterized by the relatively narrow 0 degree temperature range used in the processing. The time taken at a particular curing temperature is a parameter in the crosslinking fibres.The narrow curing temperature range of conventional crosslinking agents such as those mentioned above is due to their chemical reactivity.Most crosslinking agents have dual function reactivity and will withstand the chemical BK at a temperature sufficient to cause the functional groups of the crosslinking agent (eg the aldehyde group in ve formaldehyde or the carboxylic acid group in citric acid) to react with the crosslinking sites in the cellulose fiber (ie the hydroxy group). In general, crosslinking occurs rapidly once a sufficient temperature is reached to form a bond between the agent and the fibres. Thus there is a need in art for a crosslinking agent which allows greater flexibility in the production of interwoven fibers with specific and desirable properties. More specifically, a safe and economical 0 crosslinking agent that can be cured over a wide range of temperatures is needed to produce similarly interwoven fibers that have a wide crosslinking range and related remarkable absorbent properties. Despite the advantages offered by polycarboxylic acid crosslinking agents, certain cellulosic fibers, especially cellulosic fibers crosslinked with polycarboxylic acids, have weight

Low molecular weights such as citric acid lose their tangles over time and revert to tangle-free fibers. For example, the crosslinked fibers of citric acid show a significant loss of tangle upon storage. This reversal of tangles generally thwarts the goal of tangling the fibers, which increases the size and strength of the fibers. Therefore, the useful storage life of fibers crosslinked with these poly©carboxylic acids is short and renders the fibers in a way of limited use.

The loss of entanglement leads to the loss of the distinctive properties conferred on the fibers by entanglement. Durable fibers mean those fibers that have undergone tangle loss and can be characterized by having relatively less bulk, limited absorption capacity, and lower liquid-gaining capacity than the same fibers that were originally shaped.

0 Therefore, there is a need for suitable interwoven cellulose fibers inside the fiber that give the absorbent properties and advantages that can be obtained with conventional interlocking fibers; Which, Tail an, has to be intertwined inside the loofah over the passage of days and in storage to provide an interlocking loofah that has a really long storage life. The present invention fulfills these requirements and provides other related advantages.

1 General description of AAO in an appearance; The present invention provides single chemically crosslinked cellulose fibers comprising individual cellulose fibers crosslinked from within the fiber with a polymerized polycarboxylic acid crosslinking agent. In one embodiment, the crosslinking agent is a polymerized polycarboxylic acid polymer, and in another embodiment, the crosslinking agent is a polymerized polycarboxylic acid.

Ye is a maleic acid polymer. The polycarboxylic acid crosslinked fibers of the present invention are characterized by their large size, increased absorption capacity, and improved liquid book rates (Cy) compared to non-crosslinking cellulosic fibers and conventional crosslinking agents.

In another aspect of the present invention, a method is provided to chemically form interwoven cellulosic fibers within the fiber in a single manner. In the method, a crosslinking agent is supplied to a polymerized polycarboxylic acid in a mat of cellulose fibers, and then the mat is separated into individual unseparated fibers, then the individual fibers are dried and the crosslinking agent is treated to form o tangles inside the fiber. Alternately in another aspect oof the fibers may be interwoven (eg partially) in the mat before the fibers are separated and the individual fibers are formed. Another aspect of the present invention provides a method for producing crosslinked fibers having absorbent properties that depend on the temperature at which the fibers are cured. Fahrenheit. In addition to another appearance, a method for forming interwoven fibers with stable entanglements is provided. In this method the cellulosic fibers are crosslinked with a polymerized polycarboxylic acid crosslinking agent. And still in another aspect the present invention provides a method for forming cellulose crosslinked fibers having a significantly lower level than in conventional crosslinked fibers; In this method, 1 _ cellulosic fibers are crosslinked with a polymaleic acid crosslinking agent. The present invention also provides sorbent compositions which contain crosslinked single polymer polycarboxylic acid fibers of the invention and sorbent compositions incorporating these compositions. 1 Row T 1 The present invention is directed to a polymerized polycarboxylic acid crosslinking agent for cellulose fibers 0, crosslinked cellulose fibers of polymerized polycarboxylic acid fibers, products containing such crosslinking fibers, and methods of attachment of these fibers. In one embodiment, the present invention provides for single chemically crosslinked cellulose fibers which are crosslinked within the fiber with a polymerized polycarboxylic acid crosslinking agent. As used here

The term “prea polymerized polycarboxylic acid” refers to a polymer having several carboxylic acid denatured groups available to form esterified bonds with cellulose (ie crosslinks). The polymerized polycarboxylic acid crosslinkers that are useful in this invention generally consist of monomers or co-monomers which contain contain carboxylic acid groups or 0 functional groups which can be converted to carboxylic acid groups Suitable crosslinking agents useful in the formation of crosslinked fibers of the present invention include polyacrylic acid copolymers 0 polymaleic acid copolymers acrylic acid copolymers Copolymers of maleic acid and mixtures thereof. Other suitable copolymerized polycarboxylic acids include commercially available polycarboxylic acids such as polyaspartic; glutamic; poly(©-hydroxy)0-butyric acids; polyinconic acids. "polyacrylic acid" refers to a polymerized acrylic acid (i.e., polyacrylic acid); the expression "acrylic acid copolymer" refers to a polymer consisting of acrylic acid and clin monoacrylic copolymers and low molecular weight monoalkyl PS exchange phosphinate Phosphates and mixtures thereof. The expression refers to "polymaleic acid polymer". to a polymeric maleic acid (i.e., 0 _ copolymerized maleic acid) or maleic anhydride; The expression "maleic acid copolymer" refers to a polymer consisting of a maleic acid (or maleic anhydride) and a suitable monomer; Maleic acid and low molecular weight mono-alkyl phosphinate-substituted copolymers; Phosphates and mixtures thereof. Polyacrylic acid copolymers contain polymers formed by the polymerization of edly acid SF stearate 0 acrylic acid 0 and mixtures thereof. Polymalic acid copolymers contain polymers formed by the polymerization of maleic acid; maleic acid stearate; maleic anhydrides and mixtures thereof. Polyacrylic acid and polymaleic acid copolymers are commercially available from; For example, Rohm and Hass, and examples of suitable polyacrylic acid polymers contain poly

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(co-acrylamide with acrylic acid); poly(acrylic acid combined with malic acid); Poly(ethylene co-acrylic acid) and poly(1-vinylpyrrolidone co-acrylic acid) as well as other polyacrylic acid derivatives such as poly (ethylene co-cured with methacrylic acid) and poly (methyl methacrylate co-capped with methacrylic acid) . Suitable polymalic acid copolymers contain poly(methylvinyl ether covalent with maleic acid); Pulsi 0 (co-styrene with malic acid) » and poly (vinyl chloride co-coated with vinyl acetate with maleic acid ale available). The polymers representing the aforementioned polycarboxylic acid have multiple molecular weights and molecular weight limits from commercial sources. from about 0 to 10,000 g/mol. It is preferable for polyacrylic acids to have polymers with weights of 0. It is preferable for polymers to have 150801. to about 150010 molecules in the range of about polymaleic acid with molecular weights in the range from 300 to 19060. On the contrary, factors Crosslinking polymerized polycarboxylic acid with high molecular weight In the present invention, the aforementioned polycarboxylic acids and ©: -© have molecular weights not exceeding about 1 g / mol. 0 As mentioned above, they are also polymers. A polycarboxylic acid useful for the formation of the crosslinked cellulose fibers of the present invention. Suitable carboxylic acid copolymers include acrylic acid copolymers (ie copolymers of acrylic acid) and maleic acid copolymers (ie copolymers of maleic acid) and have molecular weights ranging from about 0.0001 lm/mg to about 50,806,085. Preferred more than about 0100 to about 0

The weight ratio of acrylic or maleic acid to co-monomer of these copolymers can range from about 1:01 to about 1:1 and more preferably from about 0:8 to about

7 Co-monomers suitable for forming polyacrylic© and polymaleic acid copolymers contain any copolymer which, when copolymerized with an acrylic acid or maleic acid (or their esters) gives a polycarboxylic acid crosslinking agent which yields crosslinked cellulose fibers having the characteristic properties of size The absorption capacity, liquid gain rate, and entanglements within the fiber are stable. It contains representative common monomers; For example; on ethyl acrylate; vinyl acetate; acrylamide; vinyl pyrrolidone; methacrylic acid; Ve Methylphenyl Ether; styrene; Vinyl chloride, etachonic acid and monosuccinic thiartrate. Preferred monomers contain vinyl acetate; methacrylic acid; Methylphenyl ether and itaconic acid. Polyacrylic acid and polymaleic acid copolymers prepared from the above-mentioned copolymer models are available in various molecular weights and molecular weight limits from commercial sources. In a preferred embodiment, the polyacid copolymer

A carboxylic copolymer of acrylic and malic acids. The polycarboxylic acid polymers useful in forming the crosslinked fibers of the present invention contain self-catalytic polycarboxylic acid polymers. As used herein, the term “self-catalyzed polycarboxylic acid polymer” denotes a polymer derivative of a polycarboxylic acid that forms crosslinks with cellulose fibers at a practical rate at mild 0 curing temperatures without the aid of a crosslinker catalyst. The autocatalytic polycarboxylic acid crosslinking agent is preferably a copolymer of either an acrylic acid or a malic acid and a low molecular weight mono-alkyl substituent of phosphines and phosphonates. These “copolymers” may be prepared with hypophosphorous acid and its salts, eg sodium hypophosphite and/or

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Phosphorous acids as chain transformation agents. Polycarboxylic acid polymers can be used

as well as its copolymers, which are highly described individually by the conjugate; or in combination with factors

Another well-known tangle in Art.

Anyone well versed in the range of polycarboxylic acid polymers will recognize that the polycarboxylic acid polymer crosslinking elements described above can appear in

Different forms of free acid and its salts. Although the free acid form is

Preferably, it is certain that all images of the acid are contained within the scope of the present invention. And for models

The invention, which contains a polymer of polymaleic acid, is polymaleic acid with ace

low pH which has a pH of about 1 to about ; be preferred.

0 Cellulose fibers crosslinked with polycarboxylic acid crosslinkers described above can be produced at practical rates without a catalyst, provided that the pH of the crosslinking reaction is kept at a neutral pH (i.e. the pH ranges from about 1 to about *) and is described The effect of the pH of the crosslinking solution on the sorption capacity of a typical polymalic acid crosslinked fiber formed according to the present invention in Example (8). It is preferable to remain

0 pH of the crosslinking solution at a pH value in the range of about JY of about 3 and alternately; Polycarboxylic acid crosslinking agents can be used with a crosslinking catalyst to accelerate the crosslinking reaction between the crosslinking agent and the cellulose fibers to produce the crosslinked cellulose fibers of the present invention. Suitable crosslinking catalysts contain any stimulant that increases the rate of crosslinking

Ye forms an ester bond between a polycarboxylic acid crosslinker and cellulose fibres. Preferred crosslinking catalysts contain phosphorous alkali metal salts. In particular, catalysts containing alkali metal polyphosphonates such as sodium hexameta phosphate and hypophosphine metal alkali metal hypophosphine are preferred. The crosslinking catalyst is typically present in the crosslinking reaction in an amount of

11 about © to about 9670 by weight of crosslinking agent. It is preferred that the catalyst be present in quantity

GL by weight of crosslinking agent. A typical method for forming circa 70010 crosslinked cellulose with the help of a catalyst is described in an example. In this method the crosslinking catalyst is added to the cellulose fibers in a similar manner by adding a crosslinking agent to the fibers as described above. The crosslinking agent can be added to the fibers before, after, or at the same time as the crosslinking agent. Therefore, the present invention presents a method for producing crosslinked fibers containing the treatment of the crosslinking agent in the presence of a crosslinking catalyst. Generally, the crosslinking catalyst promotes the formation of ester bonds between a polycarboxylic acid and cellulose fibers. The catalyst is effective in increasing the degree of crosslinking (ie the number of ester bonds formed) at a desired process temperature. For example, as shown in the figure "The crosslinking level (as assumed by the adsorption capacity) achieved at 0°F without a catalyst is compared to the crosslinking level achieved with a catalyst at m" Fahrenheit. In other words, at a required processing temperature, the use of a crosslinking catalyst gives an increase in the crosslinking process. The preparation and properties of cellulose fibers crosslinked with 7. A typical carboxylic acid crosslinker and crosslinking catalyst are described in Example 1. The crosslinked cellulose fibers of the present invention have an effective amount of a carboxylic acid crosslinker that reacts with the fibers to form crosslinks within the fiber. As used herein, the expression "effective amount of polycarboxylic acid polymer crosslinking agent" refers to an amount of crosslinking agent of eg capacity; the size; The rate (lo) is sufficient to give an improvement in the absorption (gain) or physical properties (such as entanglement within a stable, low-knot fiber) of the 0 fiber relative to conventional mode or untangled fibres; Or interwoven fibers with intertwined ends A other crosslinking agents. In general, cellulose fibers are treated with an appropriate amount of agent so that an effective amount of crosslinking agent interacts with the fibers.

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It is preferable that the crosslinking agent of a polymerized polycarboxylic acid be present in the fibers in an amount from about 1 to about 900 by weight of the total weight of the fibers. It is more preferable that the polymerized polycarboxylic acid is present in an amount of about AY about 964 wt of the total fibres, and in a more preferable form of about AT about 966 wt of the total fibres. The effect of the amount of 0 polycarboxylic acid polymerized on the size of the fibers is described; The capacity and rate of liquid gain in the examples from JN© and Example 7. In general, an increase in the amount of crosslinking agent in the fibers increases the size and strength of the fibers. In general, fibers crosslinked with GT 964 polymalic acid have a much greater liquid gain rate than fibers crosslinked by the Alas method with a typical urea-based crosslinking agent.” DMDHEU 0. As stated above the present invention relates to cellulose fibers. Which are chemically crosslinked from the inside of the fiber with a polymeric polycarboxylic acid crosslinking agent. Although other sources are available, cellulose fibers are mainly derived from wood pulp. The wood pulp fibers suitable for use with the present invention can be obtained from chemical processes well known as the Kraft and Sulfite processes with or without subsequent modification. Wood pulp fibers can also be treated with a Ne-mechanical or thermo-chemical method or a combination of them. The preferred wood pulp fibers are produced by chemical methods. Original wood fibers can be used; Recycled or secondary wood pulp fibres, modified and unmodified wood pulp fibres. The preferred starting material is prepared from the long-fiber pine type Jia southern pine; Douglas fir; Fir (a resinous white wood); Poison hemlock (fir). The specifics of wood pulp fiber production are well known to those experienced in the art. These fibers are commercially available from a number of companies, including Warehouser; to which the present invention is entrusted. For example, a suitable cellulose GL produced from southern pine that may be used with the present invention is available from Warehouse Inc. under markings 01416 FR516 PL416 (NF405 13416).

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Wood pulp fibers suitable for use in the present invention may also be reprocessed prior to use in the present invention. This pre-treatment may include a physical treatment, such as exposing the fibers to water vapor, or a chemical treatment. Although this is not considered exclusive, examples of pre-treated fibers contain the application of fire retardants for fibers; surfactants or other liquids such as water or solvents that modify the surface chemistry of the fibres. Other © pre-treatments contain antimicrobials; pigments; and thickening agents or softening agents. Fibers that have been pretreated with other chemicals such as Cm plastics and heat hardening resins can also be used. It can use a combination of preprocessors. Processing cellulosic fibers of granular binders and/or bulking aids of 0 density/softness known in the art may also be used according to the present invention. Granular binders work to bind other materials such as super absorbent polymers, along with other materials, to cellulosic fibers. Cellulose fibers treated with suitable granular binders and/or densifying/softening aids and the method of their union with cellulose fibers are disclosed in the following patents and US patent applications (7) eal Patent No. 4771 00 under the title “Polymeric Binders for Bonding Granules to (1) (: 0

A Under the heading “Organic non-polymer binders for bonding particles to” © OAVAY Patent No. Under the title “Wet-laid fiber board manufactured with oN AY binders Patent No. (0) under the title “OTOY EAL method” For bonding granules to binders". Al-Kabeer.” (1) serial number to deposited on August 11, 7 under the name “Granule binding materials that enhance the process of increasing the density of fibers.” () AYA serial number 7 and deposited on August 117, 1447” under the title "Granule Binders"; (A) serial number Ve AY YA/A filed August 117, 1997 under the title

"bond granules to fibers"; (3) Serial No. 0177/8 and filed on August 147, 1711 under the title “Binders for Bonding Water-Soluble Particles to Fibers” (01) Patent No. 1748/8647 under the title “Granule Binding Materials”;) V1) Serial No. 018718/8 filed on 117 Aug 07 under the title “Granules Attached to (VY) Fibers Patent No. 5708895 under 0 “Granules Attached to Fibers of Large Size”. They are all clearly here by reference.

A polymerized polycarboxylic acid crosslinking agent may be added to cellulose fibers by any of the methods known to produce treated fibers. For example, the polymerized carboxylic acid can come into contact with the fibers such as passing a fiber board through a pass containing the acid

Polycarboxylate.

Lis, 0 Other methods of adding polycarboxylic acid which involve a fiber spray or spray and press or dip and press in a polycarboxylic acid solution are also within the scope of the present invention. In general, cellulose fibers intertwined within the fiber in the present patent can be formed by adding a polymerized polycarboxylic acid crosslinking agent to the cellulose fibers; And separate the mat that has been processed

ve into individual fibers and then curing the crosslinking agent at a temperature sufficient to complete the crosslinking between the polymerized polycarboxylic acid and the cellulose fibres. The polymeric carboxylic acid crosslinker may be treated by heating the crosslinking agent treated fibers to a temperature and for a period of time sufficient for crosslinking to occur. The rate and degree of tangle depends on a number of factors including the moisture content of the fibres;

ye temperature; pH number; In addition to the quantity and type of catalyst. Those experienced in the art will understand the relationship between time and temperature that exists to cure a crosslinking agent. In general, the extent of processing and thus the degree of crosslinking is a function of the processing temperature. It is preferable to treat the crosslinking agents of a polymerized polycarboxylic acid in the present invention at degrees

11 Fahrenheit to about 780 Fahrenheit. The result of ©71 heat ranges from about crosslinked to acid GLY curing temperature on size and absorption capacity in relation to and generally increases the size and capacity of (As © GF oY) a typical polycarboxylic polymer in examples Fiber absorption Interlocking by increasing the processing temperature

0 In general, the cellulose fibers of the present invention may be prepared with a system and apparatus such as those described in US Patent No. EEVAVY Ling, Sir, et al.; which are incorporated herein by reference in their entirety. In short, the fibers are prepared with a system and apparatus comprising a conveyor to transport a mat of cellulose fibers through a fiber treatment area and a rod used to apply a curing agent such as a polymerized polycarboxylic acid crosslinker from upstream to the fibers in a treatment area

0 fiber; a fiber apparatus for the complete separation of individual cellulose fibers comprising the mat to create a fiber output comprising virtually unbroken cellulose fibers and a desiccant associated with the fiber apparatus for evaporating residual moisture from the flash method and for curing the crosslinking agent(s); To form dry, cured interlocking fibers. LS is used herein, the term "mat" refers to any non-woven board configuration that includes

ve cellulose fibers or other fibers which are not covalently bonded together. GLI contains fibers obtained from wood pulp or other sources including cotton rags; cout herbs; seed husk stick; corn sticks; or any other suitable source of cellulose fibres, which shall be placed on a board. The cellulose fiber mat is preferably in the form of an elongated sheet, and it can be one of several sheets in the form of a bundle of distinct sizes, or it can be a roll.

0 connected. Each cellulose fiber mat is conveyed by a conveyor such as a JB sernaval or a series of driven rollers. The conveyor carries the mats through the GUY treatment area

In the fiber treatment area, a polymerized polycarboxylic acid crosslinking agent is applied to the cellulose fibers. It is preferable that the polymerized polycarboxylic acid be applied to one or both surfaces of the mat using any of the various methods known in the art which include spraying, spinning or dipping. Once the crosslinking agent has been applied to the mat, the crosslinking agent © can be distributed evenly throughout the mat; For example ; By passing the mat through a pair of rotating cylinders. After treating the fibers with a crosslinking agent, the impregnated mat is fibrous by passing the mat through a grinding hammer. The hammer mill separates the mat into a single component of cellulosic fibres, which the dryer performs two successive functions, the first is to remove the residual moisture from the fibers and the second is to treat the polymerized polycarboxylic acid crosslinking agent. In one embodiment, the dryer includes a pre-drying area to receive the fibers and to remove residual moisture from the fibers by flash drying; And another drying area for crosslinking agent treatment. Alternately in another embodiment the treated fibers are blown through a flash dryer to remove residual moisture and then transferred to an oven where the treated fibers are wed processed. The interwoven cellulose fibers in this invention show distinctive absorbent properties that include increased absorption capacity; increased absorption rate; increased volume; And increased bounce (backward bounce) in relation to untangled fibers. In general, the absorption capacity of fiber (recorded in units of g water/g fiber) and the water absorption rate (milliliter/sec) increase by 0; volume cm”/g; and resilience (i.e. the extent to which the fibers bounce back) by increasing the tangle. For the crosslinked fibers of the present invention, increased crosslinking can be achieved either by contacting the fibers to be crosslinked with increased amounts and/or concentrations of a crosslinking agent or alternately by increasing the temperature at which the acid-treated fibers are treated.

and Polly Mallick. The preparation and some specifications of some typical polymeric polycarboxylic acid crosslinked cellulose fibers in the invention are described in Example 1 (polyacrylic acid crosslinked fibers) and Examples from ; to © (polymalic acid crosslinked fibers). As Ladle above, the absorption characteristics of the crosslinked cellulose GLYs in this invention are generally affected by the extent of crosslinking by a polymerized carboxylic acid crosslinking agent. Moreover, it was discovered that it is possible to control the extent of crosslinking with a polymerized polycarboxylic acid, and thus the resulting absorption qualities of the fibers, by the temperature used in treating the treated fibers (i.e. leading to the formation of an ester bond). At high processing temperatures, more ester bonds are formed between the two acids polycarboxylate and fibers, resulting in more tangles. 0 Thus, in another aspect, the invention, Ja, presents a method for forming interwoven cellulosic fibers that have adsorption properties that depend on the processing temperature. In this method, the crosslinked fibers are generally prepared as described above using a polymeric carboxylic acid crosslinking agent, then treated at a treatment temperature in the range from about 771 Fahrenheit to about TAY Fahrenheit, and the treatment temperature is chosen in order to achieve the required properties of the ability to absorption»; vo volume; rebound and liquid gain rate. The effect of the change in the curing temperature on the properties of the crosslinked fibers of a polymerized carboxylic acid is described as examples 1-? The effect of curing temperature for crosslinking fibers of maleic acid is also described in example (0) and as noted above, an increase in curing temperature generally leads to crosslinking fibers having increased size and absorption capacity. Boards or mats having absorbent capacity, volume and resilience.For example, these interwoven fibers can be combined with other fibers containing other interwoven and non-knitted fibers.dai, i. Boards and mats on polycarboxylic acid crosslinked fibers can be incorporated into products

Various absorbents including, for example: paper sheets; disposable diapers; menstrual pads; Tampons and bandages. The interwoven polycarboxylic acid polymerized fibers of the present invention exhibit a density that remains virtually unchanged over the life of the fiber fabric made from such fibers. This resistance to aging or decrease in density is related to the stability of crosslinks within the fiber formed using polymerized polycarboxylic acid crosslinking agents. On the other hand, cellulose fibers crosslinked with citric acid showed a significant increase in density associated with a loss in volume and absorption capacity over the course of days. In general, an increase in density shows a decrease in the level of crosslinking (ie reversed) in the fibres. In addition to the increase in density, the decrease in entanglement in fibrous tissue results in tissue with a non-bulky size of 0 and thus reduces the resorption capacity and fluid acquisition capacity. Thus, the present invention presents a method for forming cellulose fibers that have crosslinks inside the stable fiber, which contains cellulose fibers crosslinked with a polymerized carboxylic acid crosslinking agent. Increased density returned (Jil) from about 96700, and it is more preferable less than about 9600, and in contrast, GLE is The crosslinking of citric acid increased a reflux density of about 1600 which is much greater than 1 the reflux density value of the fiber formed according to the present invention. The effect of aging (i.e. rebounding of the crosslinking process) on the density of fibrous textiles consisting of crosslinked polyacrylic acid fibers and fibrous textiles composed of crosslinked fibers of citric acid is described in an example (11). Polymaleic acid remains virtually unchanged in the aging process, which indicates that fibers crosslinked with polymaleic acid© also maintain their crosslinking.In another aspect of the present invention a method for forming crosslinked fibers having a low knot level is provided.In this method cellulosic fibers are crosslinked with an acid polymer Polymalic as generally described is dle and is typical for poly'malic acid crosslinked fibers resulting in a knot level less than about 96010 and preferably less than about 965. The fibers have

crosslinking with a typical urea-based crosslinking agent; (DMDHEU) has a knot level of about 9670 which is significantly greater than the knot level of the formed fibers according to the invention. A comparison of the knot level for crosslinking fibers of polymaleic acid and DMDHEU is described in an example. In embodiment al the present invention presents fibers cellulose which are crosslinked with a mixture of crosslinking agents which contain the polymerized polycarboxylic acid described above and a second crosslinking agent.It is preferable to crosslink the fibers with a second crosslinking agent having a lower curing temperature than that of the polymerized carboxylic acid.For this model the second crosslinking agents possess Curing temperature lower than the curing temperature of polycarboxylic acid crosslinking agents; ie, 0 less than about 771 F. The second preferred crosslinking agents contain urea-based derivatives such as for example urea treated with methyl alcohol; ureates A alles dla with methyl alcohol; cyclic ureates with low alkaline substitutions treated with methyl alcohol; dihydroxyuriate with methyl alcohol; Other suitable urea derivatives contain 0 dimethyl dihydroxyurea (DMDHU ?-dimethyl-;; 10 z-hydroxy-7-imidazole danione); Dimethyloldihydroxy Cold Urea (DMDHEU) 1,7-Dihydroxymethyl-;-09-Dihydroxy-?-imidazole dione); dimethylol (DHEU) bus 4; lame hydroxy-7-imidazole dienone); dimethyl ethylene urea (DMEU) 017-dihydroxymethyl-7"-imidazole dienone); dimethyldihydroxy0ethyleneurea (001;4;©-dihydroxy-"); 7-dimethyl-7 -Imidazole Dienone My favorite second-crosslinking agents contain polycarboxylic acids containing, for example, citric acid; tartaric acid; malic acid; oe clin aS glutric acid; And acid

Monosuccinic tartrate. In more favorable embodiments, the second crosslinking agent is citric acid or

Maleic acid (or maleic anhydride). :

Other preferred crosslinking agents include glyoxal acid and glyoxylic acid. while

The composition of the crosslinking mixture can be changed to form crosslinked cellulosic fibers with desired properties, with polymerized polycarboxylic acid (PCA) being the dominant crosslinking agent in the mixture. There is generally a factor

The second crosslink in the mixture in an amount from about © to about 0 968 by weight of the crosslinking mixture

total.

The characteristics of typical crosslinked cellulose fibers prepared from mixtures of acid are explained

Polyacrylic, malic acid, and citric acid in examples » 01, respectively. Generally, size 0 and absorption capacity of crosslinked cellulose fibers with polymerized polycarboxylic acid mixtures

They are greater than in the case of fibers that are crosslinked with either a polycarboxylic acid or a crosslinking agent

The second solo. Moreover, the problem of discoloration of the interwoven fibers has been overcome

Which crosslinked with citric acid only, using a mixture of polymerized polycarboxylic acid

Without sacrificing the beneficial aspects of the absorbency of fiber. It was found that 1_cellulose fibers crosslinked with a mixture of polymerized polycarboxylic acid and citric acid had a luster.

Improved compared to fiber crosslinking with only citric acid. In addition, the resistance of Dla

crosslinking of crosslinked polycarboxylic acid fibers i.e. loss of crosslinking; confer stability

For crosslinking fibers with polymerized polycarboxylic acid blends. For example while you are

Cellulose fibers crosslinked with citric acid only are susceptible to detangling, so fibers 0 crosslinked with a mixture of citric acid and a polymerized polycarboxylic acid show the properties of

Characteristic absorption and stable crosslinking.

The following examples are provided for illustrative purposes and are not limited to. to"

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Examples Preparation and Properties of a Typical Polyacrylic Acid Crosslinking Fiber: 1 Example and Polyacrylic Acid Crosslinking Fiber In this example the preparation and properties of a typical polymerized polycarboxylic acid crosslinked fiber are described. Fibreboards consisting of single cellulose fibers (commercially available from Wehrhauser under the brand name NB416) were treated with a polyacrylic acid (self-catalyst) having a molecular weight of about YO g/mol (commercially available under the brand Acumer 9930 from Rohm and Haas). In short, the fiberboard was fed from a roll by being continuously refilled with 0% aqueous polyacrylic acid solution and the concentration was adjusted to obtain the required level of polyacrylic acid to be added to the fiberboard.Then the treated fiberboard was transported through a micro outlet of a rotating cylinder adjusted to remove enough liquid to provide a fiberboard having a moisture content of about 9600 and after passing through the outlet of the cylinder the wet fiberboard was fibrous by passing the board through a grinding hammer The resulting fibers were blown through a rotating storm flash dryer (J) where the fibers were collected The treatment of the treated fibers was completed by placing the fluff fibers in a laboratory oven and heating them up to TAC Fahrenheit for a period of minutes The absorption capacity and volume of the prepared fibers were determined as described above by the following procedures: An absorbent quality analyzer for fibers (Waerhouser Company) was used. Federal Way, WA to hire K measure volume (wet and dry); absorption capabilities; And resilience when wet and that of GLY wood pulp. 0 _ In the procedures, a sample of a gram of wood pulp fibers is placed through a small mill to establish the wood pulp and then placed with air in a tube. Then the tube is placed in a Pascal vacuum analyzer and the dT was determined, then a piston was placed on a fluff filling with a pressure of FAQ of the filling.

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Pascal and then recalculate the volume. It is @Y,0, and the weight is increased to obtain a capacity pressure. The result is obtaining two volume readings for the fluff pulp at two different pressure values. While co at a pressure of 9, ?kPa, water was introduced into the bottom of the tube (bottom of the packing). The time 0 required for the water to reach the plunger is calculated. From this, the determination of the absorption rate and the time of determination of the final volume of the wet filler at 7.5 kPa are calculated. After that, the absorption Lad is calculated. The plunger 0 is withdrawn from the tube and the wet wad is allowed to expand for 010 seconds. The piston is repositioned

Aon at 0,000 kPa and the volume is specified. The final volume of the wet filling in Pascal is the wetted volume (cm/g) of the pulp produced. The capacity is determined by weighing the wet filling after draining the water from the device and recording it as grams of water per gram of dry pulp. The SAAN was summarized to 964 by weight 1, the absorption capacity and the wetted volume of the crosslinked fibers, which have 0 in addition to (1). A union of crosslinked fibers of polyacrylic acid, which was prepared as it was prepared, and the board size was calculated. A 0:7 was described above and untreated fibers at a ratio of (1). Lodge summarization of the dry volume measurements in fiber capacity and volume Polyacrylic acid crosslinker (1) Table 10 Treated fibers (cm”/g) | (pf pu) Polyacrylic in fibers | (g/g) Pa 01 Laa Laa 961 6 7, 7 %Y yo,Y 11 11 or 1 wound VV, ¢ %¢

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Increasing the amount of polycarboxylic acid from the fibers (1), and the results summarized in a table are shown, increases the absorption capacity of the fibers and also increases the size of the acidified panels of crosslinked polycarboxylic acid fibers. Polyacrylic prepared according to the above description. The results found 0 with fibers prepared in a similar way were summarized using other crosslinking agents. exerted on the fibres.The percentage of resilience recorded in the following represents the percentage increase in the volume of the fiber as a result of the decrease in the pressure exerted from *.7 kPa to Pa. k0: Resilience of various interwoven fibers (Y) Table 0 11.0 DMDHEU (NB 416) 011 DMDHU (NB 416)

VV, (NF 405) Citric Acid A (NB 416) Polyacrylic Acid 4 4 (NB 416) Polyacrylic Acid 7 High Crosslinking fibers of polycarboxylic acid (Y) as is shown in a table that is clearly larger than that observed for either a urea-based crosslinked fiber (i.e., moreover, the amount of rebound that 0 or a citric acid crosslinked fiber (DMDHEU) for a polyacrylic acid increases with increasing polyacrylic acid In the fiber, GLI was observed and the absorption capacity (g of water / g of fiber) of crosslinked cellulose fibers of polyacrylic acid was determined from 10 0 Fahrenheit to 780 + 771 Fahrenheit as described above and cured at temperatures from

A(T) The results of these crosslinked fibers as a function of the processing temperature are summarized in a table

Y¢ at temperatures (PAA) Table (*) Absorption capacity of crosslinked polyacrylic acid fibers (nn (Fernet) No. 7 for YY. 7 A "7 YE

V0,. 8 Ed via 1.1 7 VE, V TA. Table (©) shows that for a special crosslinking treatment, the adsorption capacity increases with increasing curing temperature. The results show that increasing the processing temperature increases the amount of crosslinking (i.e. ester formation between the polycarboxylic acid and the fiber) and that increasing the crosslinking of the fibers gives an increase in iad, the absorption capacity of the fiber. It is reported that increasing the amount of polycarboxylic acid crosslinking agent in the fibers increases the absorption capacity of the crosslinking fibers, with reference to the table; Increase the amount of polycarboxylic acid in the fibers. To 964 generally gives a greater increase in absorption capacity than when the amount of carboxylic acid in the fibers increases from; to 966 by weight of the total weight of the fibers. 0 Example (1): Preparation and properties of a typical polymerized carboxylic acid crosslinking fiber in the presence of a catalyst crosslinker 0 In this example, the preparation and properties of the fibers crosslinked with a polycarboxylic acid are described © - Typical polymer - Polyacrylic acid - and curing in the presence of a model crosslinker catalyst - Sodium hypophosphite 0

Yo The crosslinked fibers were generally prepared as described in Example (1) above. The fibers were treated with polyacrylic acid to produce fibers that have 967 polyacrylic acid in, by weight, in relation to 100:1 acid. Poly Acrylic. Table (;).

(degrees Fahrenheit) (g / g) (cm' / g) As seen in the example (1) above For the polycarboxylic acid crosslinked fibers in the invention, the absorption capacity and volume increase with the increase in the processing temperature. A table shows (;) that at a required curing temperature, the fibers crosslinked with polyacrylic acid in the presence of a catalyst crosslinker have greater absorption capacity and volume than similar fibers, but in the absence of a catalyst crosslinker. In the fibre, more crosslinking occurs (i.e., more ester bonds, Ve, are formed between the crosslinking agent and the fibre) in the presence of a crosslinking catalyst.

scales ¥ &; And at 967 crosslinking agents in All, the adsorption capacity of the crosslinked fibers that were prepared without a catalyst at a temperature of i. dallas Fahrenheit (VY, A) g/g; See Table 0. Only Sati is greater than that of fibers prepared with a catalyst at .m" Fahrenheit (7.1g/g; see Table.4).

© Example (©): Preparation and properties of crosslinked fibers with a typical polymerized polycarboxylic acid cross-linking agent mixture; Polyacrylic acid and DLA In this example the preparation and properties are described for a crosslinking fiber with a typical solution of crosslinking agents containing a polycarboxylic acid alia - polyacrylic acid - and a second crosslinking agent - maleic acid -. The crosslinked fibers were prepared as generally described in example (1) above. The effect of the curing temperature on the absorption capacity and size of the crosslinked fibers was compared with the crosslinking mixture with fibers treated with polyacrylic acid only. The results are summarized in In the following table, mixture one refers to fibers crosslinked with Led (0) poly acid, table g/mol and malic acid, and mixture two refers to fibers 0001 acrylic with a molecular weight of about

ve crosslinked with a polyacrylic acid having a molecular weight of about Tove g/mol and maleic acid. Table (2) 5038 Absorption (g/g) and wetted volume (cm”/g) of fibers treated with polyacrylic acid and maleic acid compared to crosslinked fibers of polyacrylic acid at different processing temperatures. (sia)

Table (0) shows that at all the examined processing temperatures, the ability to absorb and the size of the fibers crosslinked with a polycarboxylic acid in a union of polyacrylic acid and maleic acid is greater than in the case of fibers crosslinked with a single polyacrylic acid. Referring to the data for the two mixtures We find that increasing the absorption capacity and volume with respect to 0 of the two mixtures containing polyacrylic acid with a molecular weight of about 3000 g / mol can show that increasing the molecular color of polyacrylic acid gives an increase in crosslinking and thus an increase in the absorption capacity and volume, compared to a mixture. One that contains polyacrylic acid has a lower molecular weight (i.e., 000810 g/mol). Example (8): Methods for forming crosslinked cellulose fibers of a typical polymeric polycarboxylic acid; Example Methods for forming crosslinked cellulosic fibers polymerized with NMPA in the present invention Wood pulp boards (prepared from kraft wood pulp) were treated with polymalic acid (Axiomer 4701 Rohm & Haas) according to the following procedures. Shortener 0 south is commercially available from Wei Rhouser under the brand NBA16 from a roll through a tub that is continually refilled with a chemical crosslinking solution. The board to be treated is then passed through a narrow outlet of a rotating cylinder adjusted to dispense enough solution so that the treated wood core board has 0 moisture content. The concentration of the crosslinking agent in the vat was adjusted to obtain the required level of chemical added to the wood pulp board. Sodium hypophosphite 00 was used as a catalyst at a level of 1:1 (catalyst: crosslinking agent). After the treated board passed through the outlet of the rotating cylinder, the board was passed through a grinding hammer to fibrous the pulp. The pulp was then passed through a flash dryer into a rotating turret where the treated fluff was collected. The OLS curing of the treated pulp was done by placing it in an oven at the curing temperature (eg FY to 7800 F) for ¾ minutes.

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The performance specifications (volume; ability to absorb capacity; liquid acquisition rate) were explained crosslinked for a typical polymaleic acid polymer formed by methods GLY (hold level) 8. mentioned above in examples (from © to example 0) ( : Volume and absorption capacity of crosslinked cellulosic fibers of a typical polymaleic acid This example illustrates the size and absorption capacity of fibrous mats composed of crosslinked cellulosic fibers of typical polymaleic acid in the present invention. A crosslinking of a typical poly: maleic acid has been prepared as Described in example (£) above. In short, Southern Pine Pulp Fiber (Wairhouser Co.; Mark 803416) was treated with various amounts of a polyacid crosslinker (Rohm & Haas) and cured at various temperatures. Acumer 4701 (high malic) has been designated (1) the size and absorption capacity of fibers by the procedures explained in Example 0 The absorption capacity and size for a mat formed from interwoven fibers of polymalic acid (i.e. 701 Acumer and variable amounts of typical NB416 prepared from wood pulp fibres.

Vet (Fahrenheit in tables 7400 by weight of fiber) at a processing degree of 96 As + 4 7, respectively.

Tee Table (1) The size and absorption capacity of cross-linked polymalic acid fibers at a processing temperature Ve Fahrenheit Dma dn h Volume (cm / g) Absorption capacity (g / g) A all tongues because z

Table (V) The adsorption capacity and volume of crosslinked GL of polymaleic acid at a curing temperature of 00 Fahrenheit Volume (cm/g) The adsorption capacity (g/g) Zn SNA and generally resulting from an increase in the crosslinking agent Polymalic acid polymer in fibers are fibers that have increased volume and absorbent capacity. The effect of changing the curing temperature (ie, from 771°F to 780°F)© on the volume and adsorption capacity of two typical polymalic acid crosslinked fibers (ie 7; by weight Acumer 107; on 113416 wood pulp fibres) prepared As described above in an example (;) in Table (A) Table (A) The size and adsorption capacity of crosslinked polymaleic acid fibers and the effect of curing temperature. on

Ye. In general, increasing the processing temperature leads to an increase in volume and absorption capacity. Example (1): Liquid gain rate of a typical polymaleic acid crosslinked cellulosic fiber In this example, the liquid gain rates of a polymerized polycarboxylic acid crosslinked absorbent garment incorporating fibers of the present invention are compared to the liquid gain rate of a © absorbent garment including crosslinked fibers DMDHEU for comparison. Preparation of polymalic acid crosslinked fibers by the method described in an example above. when ? And the; % by weight crosslinking agent based on the total fiber weight and cured at 7660 F. 0 The treated fibers were then shaped into patches to capture the liquid by placing the fibers with air in a wadding of 701 g/m. The wadding was compressed at 5080 lb/in and cut into patches which were placed in a commercially available diaper ( Kimberly-Clark) instead of the fluid acquisition layer in the diaper. Then, the fluid acquisition rates were determined for absorbent garments that include fibrous patches by the procedures described below.: Procedures for determining the fluid acquisition rate 0 The acquisition rates were determined for absorbent garments containing fibers Crosslinking of a typical maleic polymaleic acid by embedding the fibers in a commercially available nappy (Kimberly-Clark)

DMDHEU and comparison of the acquisition time of a modified comparative diaper to contain cross-fibres. The acquisition time (WA (Federal Way commercially available from Wehrhauser Company” NHB416) 0 was determined according to the procedures described below. Briefly, we measure the procedures for the time required for each one. Three doses of liquid industrial urea to spread in the diaper.

Test samples were prepared by modifying commercially available diapers. The non-woven upper layer of a commercial nappy was carefully peeled off and the acquisition layer of the nappy was removed. The absorbent formations (ie, patches of crosslinked polymaleic acid polymer and cross-comparator fibers 17) were inserted into the diaper and the non-directional layer was replaced. © Once the sample has been prepared, a “TX” mark is placed on the sample about an inch from the center of the down mat towards the front of the nappy © and a dosing ring (daa h ? inch; inside diameter ¥ inch) is placed over the XT mark. ". A funnel containing 100 milliliters of industrial urea is placed over the ring. The fluid is supplied through the dosing ring by opening the probe at the bottom of the funnel. The time is calculated in seconds from the moment the funnel is opened until the liquid is absorbed and diffused into the Ye product from the bottom of the dosing ring. This is repeated two more times, keeping in mind that Ye should wait a minute between doses. The rate of acquisition is calculated by dividing 0ml by the time taken to absorb the liquid per dose. The liquid acquisition time is recorded either by the pause length (secs) required for the liquid to be absorbed into the procedure for each of the three doses or the rate (mL/sec) at which liquid Ye is absorbed into the product for each of the doses. The aqueous solution used in the tests is a synthetic urea available from Scientific International under the trade name RICCA. The industrial urea is a brine containing NYO and 08: / sodium; a 1 [meq calcium; 7a/a 1 [meq magnesium» 1.54 96 urea by weight (dependent on total weight); In addition to other parts. The liquid acquisition rates were summarized for absorbent apparel containing a typical PMA crosslink (i.e. 108416 PMA-treated crosslinked wood pulp fiber* w; 96 wt) and a comparison DMDHEU crosslink (ie, wood pulp fiber (NHB416). In the following table (9).

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Table (4) Liquid acquisition rate for absorbent apparel containing crosslinked polymalic acid fibers.

EE surveys and table (3) were the rates of fluid acquisition for the clothing (1) as shown in the figure

Baal containing intertwined polymalic acid fibers are clearly larger than in the dressed DMDHEU. Containing fibers intertwining with the level of knots in a typical polymalic acid villous core: (V) Example 1 This example shows a level Low knots in villous pulp crosslinked with polymalic acid formed according to the present invention. The level of ganglia in a villous core crosslinked with typical polymalic acid was determined by an acoustic fractionation process. Briefly, the acoustic segmentation system uses a combination of low-frequency acoustic vibrations and an air stream to separate fibers based on their size. In this process, then (mesh) a gram of interwoven fluff pulp was distributed evenly over a sieve © mesh ye mesh. A speaker above the top of the Yoo Te VY shows the sieve being placed on top of a sieve assembly with a sieve

ABA VY The set of screens and connects to an adapter to provide the tone of its frequency Directing an air stream through the set of screens to help distribute the excited fibers during Lad minutes The tone and the air stream are separated and the fluff pulp distributed in each sieves is weighed. And after the villousness (recorded as a percentage of the contract) by taking the weight lll sieve. The knot level was set at 10 and divided by the process starting weight of the fluff pulp. The total VY 8 fluff pulp in the sieves was prepared by the wet laying method as described above in Mithshal (4). For this example, the pulp fibers contained 966 polymalic acid by weight

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The level of knots of this fiber crosslinked with polymalic acid and the comparative villous pulp was determined by the fractionation method (DMDHEU) urea lid crosslinked with acoustic dimethylol dihydroxy (01) described above. The results are summarized in a table. The level of knots in villous core crosslinked with polymalic acid (01) Table ETE | Amso The level of knots in villous core crosslinked with polymalic acid is significantly lower than in similar villous core crosslinked with DMDHEU. The effect of pH on the adsorption capacity of crosslinked fibers with polymalic acid: (A) A typical maleic example In this example, the effect of the pH of the crosslinking reaction on the adsorption capacity of a crosslinked fiber mat with polymalic acid was determined. Treating the pulp with polymaleic acid 964 as described 0, and adjusting the chemical basin of the treatment at different levels of high Ja pH, using either concentrated hydrolytic acid or sodium hydroxide as needed.The absorption capacity of the prepared fibrous mats was determined. of villous pulp crosslinked with polymalic acid at various pH values (eg 7; 7.5; 3 7.5 and 4) and TM and 7280 Fahrenheit) 310 FE Ys treated at various temperatures (for example, 0 (11). The results are summarized in Table (1). As described in example vie, the absorption capacity of crosslinked fibers with polymaleic acid: Effect of pH (11) Table | of the crosslinking solution. spies pH | pH | pH | pH | pH od treatment degree t ro r Yo Y Fahrenheit z The results showed that crosslinked polymalic acid had a pH of about ? To about ¥ gives interwoven fibers that have a higher absorption capacity. Acquisition of a fiber of interwoven cellulose fibers with typical polymalic acid. Baga: (3) Example

Gila comprehensive size and absorbency properties (i.e. volume (FAQ) This example compares the acquisition quality of a wet fiber; absorption time and absorption capacity) of a fiber crosslinked with a polymaleic acid copolymer prepared by Beleclene and a polymaleic acid copolymer ( Any (Belclene 2000 (i.e., hydrolyzed polymer formed by the polymerization of maleic anhydride, ethyl acrylic, and vinyl acetate) is available. The properties of the crosslinked fibers were also compared with the non-tangled pulp fibers commercially from FMC. Briefly, crosslinked fibers were prepared. By treating the pulp fibers with an aqueous solution containing (0) 045416 by weight crosslinking agent and 161.5 by weight sodium hypophosphite based on the total weight 7 at a pH of about ?. The crosslinking agent solution was added to the pulp board containing 0 pulp for the fibers. Hardness Then 96500 of the type of southern pine fluff 113416 is passed to give the pulp a cohesion of about ant ol the board twice through a small mill in its filling and placed with air to fibrosis the pulp.Then it was treated

Yo of fluff filling by thermal bonding through the air at 97 m for two minutes. All samples were conditioned: .9650 and examined in a medium with relative humidity, and the wet and dry volumes were determined, and the absorption capacity of the panels consisting of various fibers was high. (1) Crosslinked with a polycarboxylic acid was determined by the procedures described in the example of absorption time by the procedure described in Example (6) above. The results for the crosslinked oo (VY) fibers mixed with polycarboxylic acid and the comparison fibers are summarized in Table No. The effect of the crosslinking agent on the fiber acquisition quality. (VY) Table No. (sec) Pa (cm "/g) (g / g) The crosslinking fibers with typical maleic acid copolymers had absorption times similar to other fibers. Uncrosslinked cellulose, improved wetted size and absorption capacity compared to non-crosslinked fibers. For fibrous mats composed of crosslinked modular cellulose with a mixture of polyacrylic acid and citric acid. Modular crosslinked cellulose fibers with a mixture of polyacrylic acid and high-10 acid were prepared. (1) Citric as generally explained in an example ri with an agent mixture (NBA16) briefly treated with pine pulp fibers (Wearhouser; crosslinker of polyacrylic acid and citric acid in various formulations Then it is processed. (1) The size and absorption capacity of the resulting fibers were determined by the procedures explained above in the example of polyacrylic acid (1). The size and absorption capacity of the crosslinked fibers were summarized with (7) (i.e. 964; 967; 968 wt. Polyacrylic acid based on the total weight of the fibres); (VY) Crosslinked Fiber Volume and Capacity Table (VF) Crosslinked Fiber Table cm" / g g / g q" 4 CA %¢ [| PPA 7 \R IY 714 CA %¥ PPA %¥

YY,” AER! CA %¢ [ PPA* 7

Yt Yo CA %Y [ PPA* %Y

Yo, Ye, CA %¢ | MA %Y Raqqa 7 BC CA %Y | MA %Y read YA, IA %Y | MA %Y

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PPA* 5. A polyacrylic acid with a molecular weight of about PPA (VF) in the table indicates an acid 08 Ne 0081 a polyacrylic acid with a molecular weight of about J indicates an acid Itaconic TAs denotes MA citric maleic acid; volume and absorption capacity generally increase with increasing amount of crosslinking agent (VF) and with reference to the polyacrylic acid schedule. These interwoven fibers, which have 967 by weight, have a crosslinking factor of 0 of the total weight of the fibers. The fibers that are crosslinked with polyacrylic acid / citric acid mixtures have a greater volume and absorption capacity than in the case of fibers with the same crosslinking agent added at the same level and interwoven with either Polyacrylic acid Unit or mixtures of ASL carboxylic treated poly acids of low molecular weight. The same trend is observed in fibers with a crosslinking agent of 968 by weight of the total fibers. The results show that mixtures of polyacrylic acid / citric acid crosslinking agent give fibers that have improved size and absorption capacity compared to fibers crosslinked with polyacrylic acid alone or Low molecular weight polycarboxylic acid mixtures. Also fibers crosslinked with citric acid 167 have a lower volume and absorption capacity compared to fibers crosslinked with the same amount of polyacrylic acid. In this example the aging resistance or density rebound of textiles of fibers crosslinked with a polymerized polycarboxylic acid is described in the present invention. In general, the fibers crosslinked with polymerized polycarboxylic acid in this invention show a density that remains virtually unchanged 0 over the life of the fibrous textiles prepared from these fibers. On the other hand, the fibrous pulp crosslinked with citric acid shows a marked increase in density, followed by a decrease in volume accompanied by a decrease in absorption capacity over the course of days. In general, an increase in density indicates a decrease in level

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Tangle (i.e. bounce) in fibrous textiles. The decrease in the entanglement of fibrous tissues results in a decrease in the volume of the sage, and thus a decrease in the absorption capacity and the ability to acquire liquid. The effect of aging (i.e. resilience of the similarity process) is explained in the density of a fibrous interwoven fabric consisting of crosslinking Ad fibers with typical polyacrylic acid of the present invention and weaving with citric acid (each crosslinking agent 766). By weight based on total fiber weight) in the following. To hours A In this method, the sample was then placed at room temperature for a period of 0 hours before determining the density of fibrous textiles. The effect of accelerating aging in the density of fibrous fillings is explained.

NE lbs/inch in a table or ofan 400 that has a base weight of 0 table (1 pound) density of fibrous interwoven textiles, mainly based on

PAA %1 1,1 - YAY CAT

IAA YY VEY CA LH 7,6 YY EY The results show that the density of fibrous textiles consisting of fibers crosslinked with polyacrylic acid remains virtually unchanged after aging. On the other hand, the density of fibrous textiles .965 consisting of crosslinked fibers with citric acid increases by about, results that the fiber crosslinked with a mixture of polyacrylic acid and citric acid also cps 1: resists the increase in density. va

Also, the effect of aging acceleration on the size and absorbency of fibrous textiles was determined

It consists of fibers crosslinked with polymalic acid. Fluff pulp was prepared as described above

For example, he was subjected to the aging process described above. Size and capacity were measured

The absorbency of these fibrous textiles before and after the aging process. Store the results in the No ° table

Table (V0) Volume and Absorption Capacity of Fiber Crosslinked with Polymalic Acid: Accelerated Age

Polymaleic cm / g g g / g The results show that the aging process has no effect on the villous pulp crosslinked with acid.

Polymalec has also been indicated by the indistinct changes in the size and absorption capacity of these tissues.

The results show that fibers crosslinked with polymerized polycarboxylic acid (le) for example 0 fibers crosslinked with polyacrylic acid or polymaleic acid) maintain their crosslinking throughout

The days thus produce fibrous textiles that do not actually increase in density and do not decrease in size or shape

The ability to absorb over the days.

While the preferred embodiment is illustrated and explained in the invention, it is expected that several changes will be made to it

Without straying from the spirit and scope of invention. Z

Claims (1)

¢ 0 Elements _ of protection: 1-1 Cellulosic fibers chemically crosslinked individually, including cellulosic fibers intertwined inside the fiber Y with a polymerized polycarboxylic acid crosslinking agent, where the polymerized crosslinking carboxylic acid Y has a molecular weight of about On to about EERE 1 "- The crosslinking fibers of claim No. 1 wherein the crosslinking agent selects a 7-carboxylic acid polymer from the group consisting of a polyacrylic acid copolymer; a copolymer of maleic acid; a mixture of them. 1 *- The crosslinking fibers in Claim No. (1), where the fibers have between about 961 Y by weight and about 7600 by weight, a polymeric polycarboxylic acid crosslinking agent, Cy, calculated on the basis of the weight of the GLBU Gila that was reacted with that. 1; - The interwoven fibers in Claim No. (1), where the fibers have between about 7 964 by weight and about 768 by weight, a polymeric polycarboxylic acid crosslinking agent calculated as 3 on dry weight furniture for the fibers interacting with them. 1 #- The interwoven fibers in the Claim No. 1 No. (1) where the polymerized poly-7-carboxylic acid crosslinking agent has a molecular weight of about 800 to about 0.001 001 +- the crosslinking fibers in p Protection Victory No. (7) where the polyacid ALS polymer ¥ has a molecular weight of about 10001 to about 190080. 1 1 #- The crosslinked fibers of protection No. (Y) where the polymaleic acid polymer Y has a molecular weight of about 001 to about Nowe 1 - The crosslinked fibers of protection No. (Y) ) where the polymaleic acid polymer is a polymaleic acid with a low pH having a pH of about ¥3 to about 3" 1 8- Crosslinked fibers in claim No. ( \ ) where the poly/carboxylic acid polymer is a polymer of acrylic acid and maleic acid. -0 1 interwoven fibers in claim number (7) where Ja dy is the copolymer Yo of acrylic acid on a co-monomer; It is chosen from the group consisting of acetates Y-phenyl methacrylic acid; methylphenyl ether and itaconic acid. -11 1 The interwoven fibers of claim No. (7) wherein the copolymer “Y” of malic acid is immobilized on a co-monomer selected from the group consisting of “Y” vinyl acetate” methacrylic acid; methyl vinyl ether; Itaconic acid. IY) The interwoven fibers of claim No. (1) wherein the fibers have an absorption capacity of at least about 10 g water/g fibres. -1” 1 The intertwined fibers of claim No. (1) where the fibers have a size of at least a1v 0 name of fiber gm 0 Y 1 6-_ The intertwined fibers in protection element No. (1) where the fibers have a backlash at least Y about ore -10-1 Crosslinked fibers in protection element No. (1) where the cellulosic fibers Y crosslinked inside the fiber are also interwoven with a second crosslinking agent. : 1 = Crosslinked fibers in protection element No. (V0) where an agent is selected The second crosslinking Y of the group consisting of citric acid, malic acid, itaconic acid, Y-glyoxal, 0-glyoxalic acid and urea-based crosslinking agents. Where the second crosslinking agent, Y, is citric acid. And for the fibers interacting with this. To form cellulosic fibers chemically crosslinked inside the fiber individually, it includes the following steps:— F * Adding a polymerized polycarboxylic acid crosslinking agent to a mat of cellulose fibers, as it has a crosslinking agent. This polymerized polycarboxylic acid has a molecular weight of about 0*0 . 1 * Split the mat into individual fibers that are virtually unbroken. dallas * 1" crosslinking agent to form single cellulosic fibers crosslinked within the fiber with a polymerized polycarboxylic acid A 0 1a -71 1 The method in Claim No. (10) whereby a polymerized polylacarboxylic acid crosslinking agent is selected from the group consisting of a polyacrylic acid copolymer; a polymer and a polymaleic acid; an acrylic acid copolymer; a maleic acid copolymer ¢ and mixtures thereof . All vy 1 in Claim No. (01) where the fibers have between about ¥% by weight and about 9608 by weight a polymerized polycarboxylic acid crosslinking agent calculated on the basis of 1 dry weight of the fibers reacted with. YY 1 Method in claim No. (01) wherein a polycarboxylic acid polymer is a copolymer of an acrylic acid and a maleic acid. The VE method in claim (Ye) also includes the addition of a crosslinking catalyst to the Y mat of cellulosic fibers prior to partitioning of the mat into individual fibres. 1 ©?- method in claim (YE) wherein the crosslinking catalyst is an alkali metal Y salt of a phosphorus-containing acid. 1?- The method in Claim No. (YE), where the crosslinking catalyst is sodium L-hypophosphite. 1 77- The method in Claim No. (71) also includes adding a second crosslinking agent (J) Y to the cellulose fiber mat before splitting the mat into individual fibers. 1 78- The method in Claim No. (TV) where the second crosslinking agent is selected from the group consisting of citric acid; malic acid; cli (SLA) glyoxal acid; Y glyoxylic acid ¢ Urea-based crosslinking agents. 1 4- The method in Claim No. (YY) where the fibers have between about 961 by weight Y and about 96010 by weight a second crosslinking factor calculated on the basis of the weight of dry fibers 1W and the reactants with it. -Y. 1 Method in claim (Y v) wherein the second crosslinking agent has a degree Y of curing temperature lower than that of the polymerized polycarboxylic acid 1 treatment. 1) 7 A method for forming crosslinked cellulosic fibers inside the single fiber has a processing temperature Y on which the absorption property depends, and includes the following steps: Polycarboxylate polymers Molecular weight from about m YOu to about JE are > * Fragmentation of the mat into individual fibers that are virtually unbroken; "- * Curing the crosslinking agent at a curing temperature to form individual crosslinked fibers inside the fiber A that has an absorption property that depends on the curing temperature. 1-1 The method in Claim No. 1 0 where a crosslinking agent is selected Poly Y carboxylate copolymer of the group consisting of poly stl LST copolymer 1 Polymaleic acid copolymer;Acrylic acid copolymer; Maleic acid copolymer ¢ and mixtures thereof. 1 1 Method in claim No. 1) Where the process temperature is Y temperature in the range from about YY.Fahrenheit to about YA Fahrenheit. Mr. Dr 1 - The method in Claim No. (1 0) where at least one Y depends on the processing temperature: absorption capacity; the size; recoil and fluid acquisition rate. 1 **- A method for forming cellulose fibers that have crosslinks inside the fiber includes the following steps:- " - * Adding a polymeric polycarboxylic acid crosslinking agent to a cellulose fiber mat. - * Fragmenting the mat into individual fibers that are virtually unbroken and treating the crosslinking agent to form 3 Individual fibers intertwined within the fiber with a polymerized polycarboxylic acid have stable tangles 2 . aan where fibers crosslinked with (TO) method in claim No. 1-1: Ye polycarboxylate polymer have an increased transformer density of less than about Y 1 0 The method in Claim No. (ve) where the crosslinked fibers with polymerized Y polycarboxylic acid have an increased transformer density less than about 96010. 1 6 - The method in Claim No. (0°) in which two polycarboxylic acid crosslinking agents are selected from the group consisting of a polyacrylic acid polymer; Polymer Y, polymaleic acid; an acrylic acid copolymer; Copolymer of 4-malic acid and mixtures thereof. 1 74> The method in claim (©3) also includes the step of adding a second Y-crosslinking agent to the cellulosic fiber mat before separating the mat into individual fibres. 1 5 The method in Claim No. (34) where the second crosslinking agent is chosen from the group consisting of citric acid; Maleic acid, itaconic acid » glyoxal »: ¥ glyoxylic acid and urea-based crosslinking agents. 1 1 ?- A method for forming low de crosslinked fibers comprising the following 7 steps :- , » - * Addition of a polymaleic acid polymer crosslinking agent to the cellulosic fiber mat; 3 * Fragmentation of the mat into individual fibers that are virtually unbroken; © * Treating the crosslinking agent to form crosslinked fibers inside the fiber with a polymalic acid polymer. It has a lower contract level of about +oY 1?;- The method in Claim No. (6) where the intertwined fibers inside the fiber with aan Y polymaleic have a knot level less than about Yo 1 - The method in Claim No. (£Y) wherein a polymaleic acid copolymer crosslinking agent is selected from the group consisting of a polymaleic acid homopolymer; 1 copolymer of maleic acid and mixtures thereof.