RU2671504C2 - Surface treated modified cellulose from chemical kraft fiber and methods of making and using the same - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: group of inventions relates to medicine. Modified kraft pulp fiber, which has a low degree of polymerization (DP), is described. Method for manufacturing a modified fiber and products obtained therefrom is described. Process is a one-step, iron-catalyzed peroxide treatment in an acid medium, which can be incorporated into a single stage of a multi-stage bleaching process. Products are chemical cellulose starting materials, microcrystalline cellulosic starting materials, fluff pulp and products made from them.EFFECT: fiber has improved chemical properties without physical destruction and discoloration.23 cl, 2 dwg, 30 tbl, 26 ex

Description

FIELD OF THE INVENTION

The present invention provides a chemical modification of cellulose fiber. More specifically, the present invention provides a chemically modified cellulose fiber, the source of which is bleached sulfate cellulose, which exhibits a unique set of properties that improve its performance compared to standard cellulose fiber, the source of which is sulfate cellulose, and making it suitable for use in applications, which until now have been limited to expensive fibers (such as cotton or high soda neigh alpha isomer sulphite cellulose). In particular, a chemically modified bleached sulfate fiber may exhibit one or more of the following useful characteristics, including, but not limited to, improved odor control, improved compressibility, and / or improved whiteness. Chemically modified bleached sulfate fiber may exhibit one or more of these useful characteristics, while also retaining one or more other characteristics of chemically unmodified bleached sulfate fiber, for example, maintaining fiber length and / or degree of milling. The benefits of a modified fiber can be further enhanced when the fiber is processed using one or more surfactants.

In addition, the present invention provides a chemically modified cellulose fiber, the source of which is bleached softwood and / or hardwood sulfate cellulose, which is characterized by a low or ultra low degree of polymerization, making it suitable for use as fluff pulp in absorbent products, as the starting chemical cellulosic material in the manufacture of cellulose derivatives, including ethers and cellulose esters, as well as in consumer products. As used herein, the term “degree of polymerization” may be referred to by the abbreviation “DP”. In addition, the present invention provides cellulose, the source of which is a chemically modified sulfate fiber, which has an aligned degree of polymerization of less than about 80, more specifically, a chemically modified sulfate fiber, described herein and exhibiting a low or ultra low degree of polymerization (hereinafter abbreviated “LDP” or “ULDP”) can be processed by acid or alkaline hydrolysis to further reduce the degree of polymerization d less than about 80, for example, less than about 50, making the material suitable for a variety of subsequent applications.

The present invention also provides methods for manufacturing the described improved fiber. The present invention provides, in particular, a method for simultaneously increasing the content of carboxyl and aldehyde functional groups in sulfate fibers. The described fiber is processed by catalytic oxidation. In some embodiments, the fiber is oxidized in the presence of iron or copper, and then bleached further to produce a fiber having useful whiteness characteristics, such as, for example, comparable to standard bleached fiber. In addition, at least one process is described that can provide the aforementioned improved utility characteristics without introducing costly additional steps for subsequent processing of bleached fiber. According to this less expensive embodiment, the fiber can be processed using a one-step sulfate process, such as a sulfate bleaching process. According to a further embodiment, a five-step bleaching process is proposed comprising the sequence D ₀ E1D1E2D2, where the catalytic oxidation treatment is carried out in the fourth step (E2).

Finally, the present invention provides consumer products, cellulose derivatives (including ethers and cellulose esters), as well as microcrystalline cellulose, all of which are manufactured using chemically modified cellulose fiber as described.

BACKGROUND

Cellulose fiber and its derivatives are widely used in paper, absorbent products, food or food related applications, pharmaceutical products and industrial applications. The main sources of cellulose fiber are wood pulp and cotton. The source of pulp and the processing conditions of the pulp, as a rule, determine the characteristics of the cellulose fiber, and thus the possibility of using the fiber for specific end uses. There is a need for cellulose fiber, which is relatively cheap to process and yet highly versatile, which ensures its use in a variety of applications.

Cellulose, as a rule, exists in the form of a polymer chain containing from hundreds to tens of thousands of glucose units. A variety of methods for oxidizing cellulose are known. In the oxidation of cellulose, the hydroxyl groups of the glucosides of the cellulose chains can be converted, for example, to carbonyl groups, such as aldehyde groups or carboxyl groups. Depending on the methods and conditions used for oxidation, the type, degree and position of carbonyl modifications may vary. As is known, under certain oxidation conditions, the cellulose chains themselves can be destroyed, for example, by opening glycosidic rings in the cellulose chain, and depolymerization results as a result. In most cases, depolymerized cellulose not only has a reduced viscosity, but also has a shorter fiber length than the original cellulosic material. When cellulose is destroyed, for example, by depolymerization and / or a significant reduction in fiber length and / or fiber strength, its processing may be difficult and / or it may become unsuitable for many subsequent applications. There remains a need for methods of modifying cellulose fiber that can increase the content of carboxyl and aldehyde functional groups, and these methods should not lead to a significant destruction of cellulose fiber. The present invention provides unique methods that eliminate one or more of these disadvantages.

A variety of efforts have been made to oxidize cellulose and simultaneously introduce carboxyl and aldehyde functional groups into the cellulose chain without breaking the cellulose fiber. In traditional methods for the oxidation of cellulose, it may be difficult to control or limit the decomposition of cellulose when aldehyde groups are present in the cellulose chain. Previous attempts to solve these problems included the use of multi-stage oxidation processes, for example, specific modification of certain carbonyl groups at one stage and oxidation of other hydroxyl groups at the next stage, and / or the introduction of auxiliary substances and / or protective substances, all of which can add value and produce by-products in the process of cellulose oxidation. Thus, there is a need for cellulose modification methods that are economical and / or can be carried out in a one-step process, such as a sulfate process.

The present invention provides new methods that provide significant improvements over the methods implemented in the prior art. Typically, the oxidation of sulphate pulp fibers in the prior art was carried out after the bleaching process. The inventors of the present invention unexpectedly found that it is possible to use the existing stages of the bleaching sequence, in particular the fourth stage of the five stages of the bleaching sequence, for the oxidation of cellulose fibers. In addition, the inventors of the present invention unexpectedly found that a metal catalyst, in particular an iron catalyst, can be used in the bleaching sequence to carry out this oxidation without contaminating the final product, for example, because the catalyst does not remain bound to cellulose, and as a result, a simpler removal of at least some of the residual iron before the end of the bleaching sequence than might be expected from the summary th available in technology. In addition, the authors of the present invention unexpectedly discovered that such methods can be carried out without practically destroying the fibers.

It is known in the art that cellulose fiber containing sulphate cellulose can be oxidized in the presence of metals using peroxides and / or peracids. For example, cellulose can be oxidized using iron and peroxide ("Fenton's reagent" (Fenton)). See Kishimoto et al., Holzforschung, 1998, vol. 52, No. 2, p. 180-184. Metals and peroxides, such as Fenton’s reagent, are relatively cheap oxidizing agents, which makes them somewhat desirable for large-scale applications such as sulfate processes. In the case of Fenton's reagent, it is known that during the oxidation process, cellulose can decompose in an acidic environment. Thus, it cannot be assumed that the Fenton reagent could be used in the sulfate process without significant destruction of the fibers in an acidic medium, for example, with a corresponding reduction in fiber length. To prevent cellulose degradation, Fenton's reagent is often used in an alkaline environment, where the Fenton reaction is largely inhibited. However, when using Fenton's reagent in an alkaline environment, additional disadvantages may arise. For example, cellulose may still decompose or discolor. In the processing of sulphate pulp, the cellulose fiber is often bleached in multi-stage sequences, which traditionally contain bleaching stages in a strongly acidic medium and in a highly alkaline medium, including at least one stage in an alkaline medium at the end or near the end of the bleaching sequence. Thus, unlike the processes known in the art, it turned out to be completely unexpected that a fiber oxidized in the presence of iron in the acidic stage of the sulfate bleaching process can turn into a fiber having improved chemical properties, but without physical destruction and discoloration.

Thus, there is a need for low-cost and / or one-step oxidation, which could introduce aldehyde and carboxy functional groups into a cellulose fiber, such as fiber, which is sulphate cellulose, without substantially destroying the cellulose and / or producing cellulose that is not suitable for many subsequent applications. In addition, there remains a need for introducing a large number of carbonyl groups, such as carboxyl, ketone and aldehyde groups, into the cellulose fiber. For example, it would be desirable to use an oxidizing agent under such conditions so as not to inhibit the oxidation reaction, as opposed to using a Fenton reagent in an alkaline environment, for example, to provide a high content of carbonyl groups. The authors of the present invention overcame the many difficulties of the prior art by proposing methods that satisfy these requirements.

In addition to the difficult regulation of the chemical structure of the products of cellulose oxidation and decomposition of these products, it is known that other properties can change during the oxidation process, including chemical and physical properties, and / or impurities can end up in the final products. For example, the oxidation process can change the degree of crystallinity, hemicellulose content, color and / or impurity content in the final product. Finally, during the oxidation process, the suitability of the pulp product for processing for industrial or other applications can change.

Wood pulp bleaching is usually carried out in order to selectively increase the brightness or whiteness of the pulp, usually by removing lignin and other impurities, without affecting the physical properties. Bleaching of chemical cellulose, such as sulphate pulp, typically involves several different bleaching stages to achieve the desired whiteness with good selectivity. Typically, the bleaching sequence includes steps carried out at alternating pH values. This alternation helps to remove impurities that are formed in the bleaching sequence, for example, by solubilization of lignin decomposition products. Thus, it is generally assumed that the use of a number of acidic steps in a bleaching sequence, for example, three acidic steps in a sequence, cannot provide the same whiteness as alternating acidic and alkaline steps, such as acid-base-acid. For example, in a typical DEDED sequence, a product having a higher whiteness is produced than in a DEDAD sequence (where A stands for acid treatment). Accordingly, in a sequence in which there is no intermediate alkaline stage, a product of comparable whiteness is still produced, which a specialist in the art would not have expected.

As a rule, although it is known that certain bleaching sequences can have advantages over others in the sulfate process, the reasons on which any advantages are based are not completely understood. Regarding oxidation, there are no studies demonstrating any preference for oxidation, in particular the multi-stage sequence step, or any evidence that fiber properties can be influenced in subsequent oxidation / treatment steps. For example, in the literature of the prior art does not describe any preferences regarding the late stage of oxidation compared to the early stage of oxidation. According to some embodiments of the present invention, uniquely practiced methods are provided, in particular stages (for example, final stages of the bleaching process) that provide advantages in the sulfate process and which produce fibers having a unique set of physical and chemical characteristics.

In addition, with regard to whiteness in the sulfate bleaching process, it is known that metals, in particular transition metals, which are naturally present in the cellulosic starting material, are unfavorable for the whiteness of the product. Thus, in bleaching sequences, the goal is often to remove certain transition metals from the final product to achieve a given whiteness. For example, chelating agents can be used to remove metals from cellulose that are present for natural reasons. Thus, since the task is to remove metals from cellulose that are present for natural reasons, a person skilled in the art, as a rule, should not introduce any metals into the bleaching sequence that could increase the difficulty in obtaining products with high whiteness.

In addition, with regard to iron, the introduction of this material into cellulose leads to significant discoloration, close to discoloration, which occurs, for example, in the process of burning paper. This discoloration, similar to paper discoloration during combustion, has so far been considered irreversible. Thus, it was assumed that when bleaching wood pulp by the introduction of iron, cellulose will experience a permanent loss of whiteness, which cannot be restored by additional bleaching.

Thus, although it is known that iron or copper and peroxide can be used for the cheap oxidation of cellulose, they have not yet been used in the process of bleaching cellulose in such a way as to provide whiteness comparable to the standard sequence without using oxidation steps in the presence of iron or copper . As a rule, their use in cellulose bleaching processes is undesirable. Unexpectedly, the authors of the present invention were able to overcome these difficulties and, according to some variants of implementation, to propose a new low-cost method for the oxidation of cellulose in the process of bleaching cellulose in the presence of iron or copper. In some embodiments, the methods described herein make it possible to obtain products that have characteristics that are very unexpected and run counter to the predictions made based on the descriptions of the prior art. Thus, by the methods of the present invention, products superior to those of the prior art can be manufactured, and more economical production can also be carried out.

For example, it is generally recognized in the art that metals, such as iron, bind well to cellulose and cannot be removed by conventional washing. As a rule, the separation of iron from cellulose is difficult and expensive, and this requires additional process steps. The presence of a high residual iron content in the pulp product is known to have several drawbacks, in particular in the pulp and paper production process. For example, iron may discolour end products and / or may not be suitable for applications in which the end product comes in contact with the skin, for example, in the case of diapers and wound dressings. Thus, it should be assumed that the use of iron in the sulfate bleaching process will have several disadvantages.

To date, the oxidative treatment of sulfate fiber to increase the content of functional groups has often proved to be a limited oxidative treatment after bleaching the fiber. In addition, the known processes for introducing more aldehyde groups into the fiber also cause a corresponding loss in brightness or quality of the fiber. In addition, the known processes, as a result of which the content of aldehyde functional groups in the fiber increases, also lead to the loss of carboxyl functional groups. The methods of the present invention do not suffer from any of the aforementioned disadvantages.

Sulphate fiber made by chemical sulphate treatment of cellulose is a cheap source of cellulose fiber, which, as a rule, retains its length during the processing of pulp, and usually end products having good whiteness and strength characteristics are obtained. For this reason, they are widely used as paper products. However, standard sulfate fiber has limited applicability in subsequent applications, such as the manufacture of a cellulose derivative, due to the chemical structure of the cellulose that results from standard sulfate treatment and bleaching of cellulose. Typically, standard sulfate fiber contains an excessively large amount of residual hemicellulose and other naturally occurring materials that can affect subsequent physical and / or chemical modification of the fiber. In addition, standard sulfate fiber contains a limited number of chemical functional groups, as a rule, is tough and does not have a high compression ability.

The stiff and rough nature of the sulfate fiber may require the application of layers or the addition of various types of materials, such as cotton, in products that must come in contact with human skin, such as diapers, hygiene products and thin paper products. Accordingly, it may be desirable to manufacture cellulose fiber having increased flexibility and / or softness in order to reduce the required use of other materials, for example, in a multilayer product.

Cellulose fiber in such products that must absorb body excreta and / or body fluids, such as diapers, adult incontinence products, wound dressings, sanitary napkins and / or tampons, is often exposed to ammonia that contains excreta and / or body fluids and / or ammonia produced by bacteria that contain excreta and / or body fluids. It may be desirable for such products to use cellulose fiber, which not only provides volume and absorption capacity, but which also provides odor reduction and / or has antibacterial properties, for example, it can reduce the smell of nitrogenous compounds such as ammonia (NH ₃ ). To date, the modification of sulfate fiber through oxidation, which improves its ability to limit odor, inevitably caused an undesirable decrease in brightness. There is a need for a cheap modified sulphate fiber that exhibits good absorption characteristics and / or odor limits while maintaining good whiteness characteristics.

In today's market, consumers require absorbent products, such as diapers, adult incontinence products, and sanitary napkins that are thinner. The design of ultra-thin products requires a reduction in fiber density, which can lead to loss of product integrity if the fiber used is excessively short. Chemical modification of sulfate fiber can lead to loss of fiber length, which makes it unacceptable to use it in certain types of products, such as ultra-thin products. More specifically, sulfate fiber treated to increase the content of aldehyde functional groups associated with improved odor control may suffer from a loss of fiber length during chemical modification, which makes it unsuitable for use in ultra-thin product designs. There is a need for a cheap fiber that is compressible without loss of fiber length, which makes it uniquely suited for ultra-thin structures (i.e., the product retains good absorption capacity based on the amount of fiber that can be compressed, taking up less space while maintaining product integrity while reducing fiber density).

Conventional cellulose sources that were suitable for use in the manufacture of absorbent articles or thin paper products were also not suitable for use in the subsequent manufacture of cellulose derivatives such as cellulose ethers and cellulose ethers. The manufacture of low viscosity cellulose derivatives from high viscosity cellulosic starting materials, such as standard sulphate fiber, requires additional manufacturing steps that additionally require significant costs, while generating undesired by-products, and reducing the overall quality of the cellulose derivatives. Containing cotton fluff and having a high alpha isomer fraction, sulfite cellulose, which typically has a high degree of polymerization, is typically used in the manufacture of cellulose derivatives such as ethers and cellulose ethers. However, the manufacture of cotton fluff-containing sulfite fiber having a high degree of polymerization and / or viscosity is expensive due to the cost of the starting material in the case of cotton; high costs of energy, chemicals and the environment are required to process and bleach pulp in the case of sulfite pulp; and also requires significant cleaning processes that are carried out in both cases. In addition to the high cost, there is a decrease in the available supply of sulfite pulp to the market. Thus, this fiber is very expensive and has limited applicability in the manufacture of pulp and paper products, for example, where an increased degree of polymerization or increased viscosity of the pulp may be required. For the manufacture of cellulose derivatives, this pulp is a significant part of the total production costs. Thus, there is a need for a low cost fiber, such as a modified sulfate fiber, which can be used in the manufacture of cellulose derivatives.

In addition, there is a need for cheap cellulosic materials that can be used in the manufacture of microcrystalline cellulose. Microcrystalline cellulose, which is widely used in food, pharmaceutical, cosmetic and industrial products, is a purified crystalline form of partially depolymerized cellulose. The use of sulfate fiber in the manufacture of microcrystalline cellulose without the introduction of a large-space process steps after bleaching has been limited to date. The manufacture of microcrystalline cellulose typically requires a highly purified cellulosic starting material that undergoes acid hydrolysis to remove amorphous segments of the cellulose chain. See US patent No. 2978446 (Battista and others) and US patent No. 5346589 (Braunstein and others). The low degree of polymerization of the chains after removal of the amorphous cellulose segments, called the term “aligned degree of polymerization”, is often the starting point for the manufacture of microcrystalline cellulose, and its numerical value depends primarily on the source and processing of cellulose fibers. The dissolution of non-crystalline segments from standard sulfate fiber typically destroys the fiber to such an extent that it becomes unsuitable for most applications, due to at least one of factors such as (1) residual impurities; (2) the absence of sufficiently long crystalline segments; or (3) a cellulose fiber is formed having an excessively high degree of polymerization, typically between 200 and 400, to make it suitable for use in the manufacture of microcrystalline cellulose. A sulphate fiber having a high purity and / or reduced value of the aligned degree of polymerization, for example, would be desirable as a starting fiber, which can provide increased flexibility in the manufacture and use of microcrystalline cellulose.

According to the present invention, a fiber having one or more of the described properties can simply be made by modifying a typical sulfate treatment of cellulose, including a bleaching process. The fiber of the present invention overcomes many of the limitations that are associated with the known modified sulfate fiber discussed above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of the final capillary measured using a CED viscosity of a 0.05% solution as a function of percent peroxide consumption.

FIG. 2 is a graph of the relationship between wet strength and dry strength, illustrated as a function of the wet strength of the polymer.

DESCRIPTION

I. Methods

The present invention provides new methods for treating cellulose fiber. According to some embodiments of the present invention, there is provided a method for modifying a cellulosic fiber, comprising producing a cellulosic fiber and oxidizing the cellulosic fiber. As used herein, all the terms “oxidized”, “catalytically oxidized”, “catalytic oxidation” and “oxidation” are to be understood as interchangeable, and they mean treating the cellulosic fiber with at least a catalytic amount of at least one metal, which is iron or copper, and at least one peroxide, such as hydrogen peroxide, so that at least some of the hydroxyl groups of the cellulose fibers are oxidized. The expression “iron or copper” and, likewise, “iron (or copper)” means “iron or copper, or a combination thereof”. In some embodiments, oxidation involves simultaneously increasing the content of carboxyl groups and aldehyde groups of cellulose fiber.

The cellulosic fiber used in the methods described herein can be produced using coniferous fiber, hardwood fiber, and mixtures thereof. In some embodiments, the modified cellulosic fiber is made from coniferous wood, such as southern pine. In some embodiments, the modified cellulosic fiber is made from hardwood, such as eucalyptus. In some embodiments, the modified cellulosic fiber is made from a mixture of coniferous and deciduous wood. According to a further embodiment, the source of the modified cellulosic fiber is a cellulosic fiber that has been previously subjected to full or partial sulphate treatment, i.e., sulphate fiber.

According to the present invention, the terms “cellulosic fiber” or “sulfate fiber” are used interchangeably unless they are expressly indicated as different, or where they are considered different by one of ordinary skill in the art.

According to at least one embodiment, the method comprises producing a cellulosic fiber and oxidizing the cellulosic fiber, in which, as a rule, the length of the cellulosic fiber is maintained.

The terms “fiber length” and “average fiber length” are used interchangeably when they are used to describe the properties of the fiber, and they mean the weighted average length of the fiber. Thus, for example, a fiber in which the average fiber length is 2 mm is to be understood as a fiber in which the length-weighted average length is 2 mm.

According to at least one embodiment, the method includes making cellulosic fiber, partially bleaching the cellulosic fiber, and oxidizing the cellulosic fiber. According to some embodiments, the oxidation is carried out during the bleaching process. In some embodiments, oxidation is performed after the bleaching process.

According to at least one embodiment, the method comprises producing a cellulosic fiber and oxidizing the cellulosic fiber, and as a result, the polymerization degree of the cellulosic fiber is reduced.

According to at least one embodiment, the method comprises producing cellulosic fiber and oxidizing the cellulosic fiber, while maintaining the degree of milling according to the Canadian standard (“degree of milling”) of the cellulosic fiber.

According to at least one embodiment, the method comprises producing a cellulosic fiber, oxidizing the cellulosic fiber and increasing the whiteness of the oxidized cellulosic fiber compared to standard cellulosic fiber.

As discussed above, in accordance with the present invention, the oxidation of a cellulosic fiber comprises treating the cellulosic fiber with at least a catalytic amount of iron or copper and hydrogen peroxide. According to at least one embodiment, the method comprises oxidizing the cellulosic fiber with hydrogen peroxide in the presence of iron. As a source of iron, any suitable source may be present that is recognized by a person skilled in the art, such as, for example, iron (II) sulfate (e.g., iron (II) sulfate heptahydrate), iron (II) chloride, double iron (II) sulfate ) and ammonium, iron (III) chloride, double sulfate of iron (III) and ammonium, or double citrate of iron (III) and ammonium.

In some embodiments, the method comprises oxidizing the cellulosic fiber with hydrogen peroxide in the presence of copper. Similarly, any suitable source recognized by one of skill in the art may be present as a copper source. Finally, in some embodiments, the method comprises oxidizing the cellulosic fiber with hydrogen peroxide in the presence of a combination of copper and iron.

According to some embodiments of the present invention, there is provided a method for treating cellulosic fiber, comprising making cellulosic fiber, treating cellulosic fiber, bleaching the cellulosic fiber, and oxidizing the cellulosic fiber.

In some embodiments, the method further includes oxygen delignification of the cellulose fiber. Oxygen delignification can be carried out by any method known to those of ordinary skill in the art. For example, oxygen delignification may be a traditional two-stage oxygen delignification. It is known, for example, that the oxygen delignification of a cellulose fiber, such as a sulfate fiber, can change the content of carboxyl groups and / or the content of aldehyde groups of the cellulose fiber during processing. According to some embodiments, the method includes oxygen delignification of the cellulosic fiber prior to bleaching the cellulosic fiber.

According to at least one embodiment, the method comprises oxidizing the cellulose fiber in at least one stage, which is a sulfate treatment of cellulose, an oxygen delignification step and a sulfate bleaching step. According to a preferred embodiment, the method comprises oxidizing the cellulosic fiber in at least one sulfate bleaching step. According to at least one embodiment, the method comprises oxidizing the cellulosic fiber in two or more than one sulfate bleaching stage.

When the cellulosic fiber is oxidized in the bleaching step, the cellulosic fiber should not be substantially affected by the alkaline environment during the bleaching process during or after oxidation. In some embodiments, the method comprises oxidizing the cellulosic fiber at an acidic pH. In some embodiments, the method includes making cellulosic fiber, acidifying the cellulosic fiber, and then oxidizing the cellulosic fiber at an acidic pH. In some embodiments, the pH is from about 2 to about 6, for example, from about 2 to about 5, or from about 2 to about 4.

The pH can be adjusted using any suitable acid that is known to the person skilled in the art, for example, such as sulfuric acid or hydrochloric acid, or a filtrate from the acid bleaching stage of the bleaching process, such as stage (D) using chlorine dioxide in a multi-stage process whitening. For example, cellulose fiber can be acidified by the addition of an external acid. Examples of external acids are known in the art and include, but are not limited to, sulfuric acid, hydrochloric acid, and carbonic acid. In some embodiments, the cellulosic fiber is acidified using an acidic filtrate, such as isolating the filtrate from the bleaching step. In some embodiments, the acid filtrate from the whitening step should not have a high iron content. According to at least one embodiment, the cellulosic fiber is acidified using an acidic filtrate from step D of a multi-stage bleaching process.

In some embodiments, the method comprises oxidizing the cellulosic fiber in one or more stages of a multi-stage bleaching sequence. In some embodiments, the method comprises oxidizing the cellulosic fiber in one step of a multi-stage bleaching sequence. In some embodiments, the method comprises oxidizing the cellulose fiber at the end or near the end of the multi-stage bleaching sequence. In some embodiments, the method comprises oxidizing the cellulosic fiber in at least a fourth step of a five-step bleaching sequence.

In accordance with the present invention, the multi-stage bleaching sequence can be any bleaching sequence that does not include an alkaline bleaching step after the oxidation step. According to at least one embodiment, the multi-stage bleaching sequence is a five-stage bleaching sequence. In some embodiments, the whitening sequence is a DEDED sequence. In some embodiments, the whitening sequence is a sequence D ₀ E1D1E2D2. In some embodiments, the whitening sequence is a sequence D ₀ (EoP) D1E2D2. In some embodiments, the whitening sequence is a sequence of D ₀ (EO) D1E2D2.

The non-oxidizing steps of a multi-stage bleaching sequence can include any conventional or subsequently detected series of steps that are carried out under traditional conditions, provided that they are suitable for use in the manufacture of the modified fiber described in accordance with the present invention, no alkaline bleaching step can be carried out after oxidation stages.

In some embodiments, oxidation is included in the fourth stage of the multi-stage bleaching process. According to some embodiments, the method is a five-step bleaching process having the sequence D ₀ E1D1E2D2, and a fourth step (E2) is used to oxidize the sulfate fiber.

In some embodiments, the permanganate number increases after oxidation of the cellulose fiber. More specifically, it can be expected that, as a rule, the permanganate number will decrease during this bleaching step based on the expected reduction in material, such as lignin, which reacts with the permanganate reagent. However, in the method described herein, the permanganate number of the cellulose fiber may decrease due to the loss of impurities, for example, lignin; however, the permanganate number can be increased due to chemical modification of the fiber. Not intending to be limited by theory, the authors believe that an increase in the content of functional groups in modified cellulose creates additional centers with which a permanganate reagent can react. Accordingly, the permanganate number of the modified sulfate fiber is increased compared to the permanganate number of the standard sulfate fiber.

According to at least one embodiment, the oxidation occurs at one stage of the bleaching sequence after iron or copper and peroxide are added and some holding time is provided. An appropriate holding time is a period of time that is sufficient to catalyze the reaction of hydrogen peroxide with iron or copper. Such a time can easily be determined by a person of ordinary skill in the art.

In accordance with the present invention, oxidation is carried out for such a time and at such a temperature that are sufficient to provide the desired completion of the reaction. For example, oxidation can be carried out at a temperature of from about 60 to about 80 ° C, and for a time of from about 40 to about 80 minutes. The desired time and temperature of the oxidation reaction can be easily determined by a person skilled in the art.

Preferably, the cellulose fiber is cooked to a predetermined permanganate number before bleaching. For example, when oxidized cellulose, the quality of which is paper or fluff pulp, is desired, the cellulosic fiber can be cooked using a dual-tank hydraulic cooking apparatus, cooking in Lo-Solids ™ mode and producing a permanganate number of about 30 to about 32 before bleaching and oxidation of cellulose. Alternatively, if oxidized cellulose is desired for the manufacture of cellulose derivatives, for example, for the manufacture of cellulose ethers, the cellulose fiber can be cooked to obtain a permanganate number of about 20 to about 24 before bleaching and oxidizing the cellulose using methods according to the present invention. In some embodiments, the cellulosic fiber is cooked and delignified in a conventional two-stage oxygen delignification process before bleaching and oxidizing the cellulosic fiber. Advantageously, delignification is carried out to a predetermined permanganate number of from about 6 to about 8 when the oxidized cellulose is intended to make cellulose derivatives, and to a predetermined permanganate number of from about 12 to about 14 when the oxidized cellulose is to make paper and / or fluffy cellulose.

In some embodiments, the whitening process is performed under conditions designed to obtain a given final whiteness of approximately 88 to 90%, including approximately 85 to approximately 95%, or approximately 88% to approximately 90% of the ISO standard. .

The present invention also provides a method for treating cellulosic fiber, comprising making a cellulosic fiber, reducing the degree of polymerization of the cellulosic fiber, and maintaining the length of the cellulosic fiber. In some embodiments, the cellulosic fiber is a sulfate fiber. In some embodiments, the degree of polymerization of the cellulosic fiber decreases during the bleaching process. In some embodiments, the degree of polymerization of the cellulosic fiber decreases at the end or near the end of the multi-stage bleaching sequence. In some embodiments, the degree of polymerization is reduced in at least the fourth stage of the multi-stage bleaching sequence. In some embodiments, the degree of polymerization decreases during or after the fourth stage of the multi-stage bleaching sequence.

Alternatively, the multi-stage bleaching sequence can be modified to provide more stable bleaching conditions before oxidizing the cellulose fiber. In some embodiments, the method comprises providing more stable bleaching conditions before the oxidation step. More stable bleaching conditions can provide a reduction in the degree of polymerization and / or viscosity of the cellulose fiber in the oxidation step when using less iron or copper and / or hydrogen peroxide. Therefore, it may be possible to modify the sequence of bleaching conditions so that the whiteness and / or viscosity of the final pulp product can be further controlled. For example, by reducing the amounts of peroxide and metal while providing more stable bleaching conditions before oxidation, it is possible to produce a product having a lower viscosity and higher whiteness than an oxidized product made under identical oxidation conditions, but with less stable bleaching. Such conditions may prove advantageous according to some embodiments, in particular in the manufacture of cellulose ethers.

According to some embodiments, the methods of the present invention further include reducing the crystallinity of the cellulose fiber so that it is lower than the crystallinity of the same cellulose fiber when measured before the oxidation step. For example, by implementing the methods of the present invention, the crystallinity index of the cellulose fiber can be reduced by 20% with respect to the initial crystallinity index, which is measured before the oxidation step.

According to some embodiments of the present invention, the methods further comprise treating the modified cellulosic fiber with at least one caustic or alkaline substance. For example, according to at least one embodiment of the present invention, a method for treating a cellulosic fiber comprises producing an oxidized cellulosic fiber, exposing the oxidized cellulosic fiber to a caustic or alkaline substance, and then dry laying the cellulosic article. Not intending to be limited by theory, the authors believe that as a result of introducing at least one alkaline substance into the modified cellulose, it is possible to obtain a cellulose fiber having a very high content of functional groups and a very low fiber length.

It is known that cellulose having a high content of aldehyde groups can have advantageous properties while increasing the wet strength of cellulose fibers. See, for example, US patents No. 6319361 (Smith and others) and No. 6582559 (Thornton and others). Such properties may be useful, for example, in the manufacture of absorbent material. According to some embodiments of the present invention, there is provided a method for increasing the wet strength of an article, comprising manufacturing a modified cellulosic fiber according to the present invention and incorporating the modified cellulosic fiber according to the present invention into an article, such as a paper article. For example, the method may include oxidizing the cellulosic fiber during the bleaching process, further treating the oxidized cellulosic fiber with an acidic or alkaline substance, and introducing the treated fiber into the cellulosic article.

In accordance with the present invention, hydrogen peroxide is added to the cellulosic fiber in an acidic environment in an amount sufficient to achieve the desired degree of oxidation and / or polymerization and / or viscosity of the final cellulosic product. For example, peroxide can be added in an amount of from about 0.1 to about 4%, or from about 1% to about 3%, or from about 1% to about 2%, or from about 2% to about 3% with respect to to dry pulp.

Iron or copper is added at least in an amount sufficient to catalyze the oxidation of cellulose with peroxide. For example, iron may be added in an amount of from about 25 to about 200 ppm based on the dry weight of sulphate pulp. One of skill in the art should be able to easily optimize the amount of iron or copper to achieve the desired level or degree of oxidation and / or degree of polymerization and / or viscosity of the final cellulosic product.

According to some embodiments, the method further comprises introducing steam, including before or after the addition of hydrogen peroxide.

In some embodiments, the final degree of polymerization and / or the viscosity of the cellulose can be controlled by the amount of iron or copper and hydrogen peroxide and the stability of the bleaching conditions before the oxidation step. The person skilled in the art understands that other properties of the modified sulfate fiber according to the present invention can be influenced by changing the amounts in which iron or copper and hydrogen peroxide are added, and the stability of the bleaching conditions before the oxidation step. For example, one skilled in the art can control the amounts of iron or copper and hydrogen peroxide, as well as the stability of the bleaching conditions before the oxidation step according to a predetermined level or to achieve a desired whiteness in the final product and / or a desired degree of polymerization or viscosity.

According to some embodiments of the present invention, there is provided a method for modifying a cellulosic fiber, comprising producing a cellulosic fiber, reducing the polymerization degree of the cellulosic fiber, and maintaining the length of the cellulosic fiber.

In some embodiments, the oxidized sulfate fiber of the present invention is not purified. Purification of oxidized sulfate fiber can adversely affect fiber length and integrity, for example, purification of fiber can cause fiber degradation.

According to some embodiments, at least a mixer, a reactor, and a washer (which are known to those skilled in the art) are used for each stage of the five-stage bleaching process.

In some embodiments, sulphate cellulose is acidified in step D1 in the washer, an iron source is also added to sulphate pulp in step D1 in the washer, peroxide is added after the iron (or copper source) at the point of addition in the mixer or pump in front of the column of step E2, sulphate cellulose reacts in an E2 column and is washed in an E2 washer, and steam can optionally be added before the E2 column in a steam mixer.

In some embodiments, iron (or copper) can be added until the end of stage D1, or iron (or copper) can also be added at the beginning of stage E2, provided that the cellulose is first acidified (i.e., before iron is added) to stage D1. Steam can optionally be introduced, including before or after the addition of peroxide.

According to an exemplary embodiment, a method of manufacturing a low viscosity modified cellulose fiber may include bleaching sulphate cellulose in a multi-stage bleaching process and reducing the degree of polymerization of the cellulose accurately or approximately at the final stage of the multi-stage bleaching process (for example, in the fourth stage of the multi-stage bleaching process, for example, in the fourth stage five-stage bleaching process) using treatment with hydrogen peroxide in acidic environment and in the presence of iron. For example, the final degree of cellulose polymerization can be controlled by the appropriate use of iron or copper and hydrogen peroxide, as described further in the Examples section. In some embodiments, iron or copper and hydrogen peroxide are present in amounts and conditions that are consistent with the manufacture of a low polymerizable fiber (i.e., a fiber with a weight average polymerization of from about 1180 to about 1830, or measured by capillary using CED, the viscosity of a 0.5% solution is from about 7 to about 13 mPa · s). In some exemplary embodiments, iron or copper and hydrogen peroxide may be present in amounts and conditions that are consistent with the manufacture of an ultra-low polymerization fiber (i.e., a fiber in which the weight average polymerization is from about 700 to about 1180, or 0 , 5% measured by capillary method using CED viscosity of a 0.5% solution is from about 3.0 to about 7 mPa · s).

For example, in some embodiments, treatment with hydrogen peroxide in an acidic environment in the presence of iron or copper may include setting the pH of sulfate cellulose to a level of about 2 to about 5, adding a source of iron to acidified cellulose, and adding hydrogen peroxide to sulfate cellulose.

According to some embodiments, for example, a method of manufacturing a modified cellulose fiber within the scope of the present invention may include acidifying sulfate cellulose to a pH of about 2 to about 5 (for example, using sulfuric acid), mixing an iron source (such as iron sulfate (II), for example, iron (II) sulfate heptahydrate with acidified sulfate cellulose when using from about 25 to about 250 ppm Fe (II) relative to the dry weight of sulfate cellulose with a consistency of from about 1% to about 15%, as well as hydrogen peroxide, which can be added in the form of a solution at a mass concentration of from about 1% to about 50%, and in an amount of from from about 0.1% to about 1.5% with respect to the dry weight of sulphate pulp. In some embodiments, the iron (II) sulfate solution is mixed with sulfate pulp at a consistency of about 7% to about 15%. In some embodiments, the acidified sulfate cellulose is mixed with an iron source and reacted with hydrogen peroxide for a period of about 40 to about 80 minutes and at a temperature of about 60 to about 80 ° C.

According to some embodiments, a method of manufacturing a modified cellulose fiber within the scope of the present invention includes reducing the degree of polymerization by treating sulfate cellulose with hydrogen peroxide in an acidic medium in the presence of iron (or copper), this treatment with hydrogen peroxide in the presence of iron (or copper) in acidic The environment is included in a multi-stage bleaching process. In some embodiments, treatment with hydrogen peroxide in the presence of iron in an acidic environment is included in one step of a multi-stage bleaching process. According to some embodiments, the treatment with hydrogen peroxide in the presence of iron (or copper) in an acidic environment is included in one step, which is carried out at the end or near the end of the multi-stage bleaching process. In some embodiments, the treatment with hydrogen peroxide in the presence of iron (or copper) in an acidic environment is included in the fourth stage of the multi-stage bleaching process. For example, the treatment of cellulose can occur in one step, such as step E2, after iron (or copper) and peroxide are added and some holding time is provided. In some embodiments, at least one mixer, reactor, and washer (which are well known to those skilled in the art) are used in each step of the five-step bleaching process, and sulfate pulp can be acidified in the washer in step D1, an iron source can also be added to sulfate cellulose in the scrubber in step D1, peroxide can be added after the iron source (or copper source) at the point of addition in the mixer or pump in front of the column in step E2, sulfate cellulose per can react in a column E2 and washed in a scrubber E2, and steam may optionally be administered before E2 column in steam mixer. In some embodiments, for example, iron (or copper) can be added until the end of stage D1, or iron (or copper) can also be added at the beginning of stage E2, provided that the cellulose is acidified before (i.e., before iron is added ) in step D1, additional acid may be added, if necessary, to set the pH in the range from about 3 to about 5, and peroxide can be added after iron (or copper). Steam can be added before or after the addition of peroxide.

For example, in one embodiment, the five-stage bleaching processes described above that use softwood pulp as a starting material can produce modified cellulose fiber having one or more of the following properties: average fiber length of at least 2.2 mm, viscosity from about 3.0 mPa⋅s to less than 13 mPa⋅s, alkali solubility S10, from about 16% to about 20%, alkali solubility S18, from about about 14% to about 18%, a carboxyl group content of about 2 meq / 100 g to about 6 meq / 100 g, an aldehyde group content of about 1 meq / 100 g to about 3 meq / 100 g, carbonyl content groups of from about 1 to 4, a degree of grinding of from about 700 ml to about 760 ml, a fiber strength of from about 5 km to about 8 km, and a whiteness of from about 85 to about 95 according to the ISO standard. For example, in some embodiments, the above-described exemplary five-stage bleaching processes can produce modified coniferous cellulose fibers having all of the above properties.

According to the following example, in which the cellulose fiber is a coniferous fiber, the above-described exemplary five-stage bleaching processes can produce a modified coniferous cellulose fiber, in which the average fiber length is at least 2.0 mm (for example, from about 2.0 mm to about 3.7 mm, or from about 2.2 mm to about 3.7 mm), the viscosity is less than 13 mPa⋅s (for example, the viscosity is from about 3.0 mPa⋅s to less than 13 mPa⋅ s or approx specifically 3.0 mPa⋅s to about 5.5 mPa⋅s, or from about 3.0 mPa⋅s to about 7 mPa⋅s, or from about 7 mPa⋅s to less than 13 mPa⋅s), and whiteness is at least 85 (for example, from about 85 to about 95).

According to some embodiments of the present invention, there is provided a method for manufacturing fluff pulp, comprising manufacturing a modified sulfate fiber according to the present invention, and then manufacturing fluff pulp. For example, the method includes bleaching a sulfate fiber in a multi-stage bleaching process, oxidizing the fiber in at least the fourth or fifth stage of a multi-stage bleaching process with hydrogen peroxide in an acidic medium in the presence of a catalytic amount of iron or copper, and then making fluff pulp. According to at least one embodiment, the fiber is not cleaned after a multi-stage bleaching process.

In some embodiments, a fiber made as described above may be treated with a surfactant. The surfactant for use in the present invention may be solid or liquid. The surfactant may be any surfactant, including, but not limited to, softeners, disintegrants, and surfactants that are not essential to the fiber, i.e. which do not affect its specific absorption rate. When used herein, a surfactant that is “not essential” to the fiber exhibits an increase in specific absorption rate of 30% or less when measured using the PFI studies described herein. According to one embodiment, the specific absorption rate is increased by 25% or less, including 20% or less, including 15% or less, including 10% or less. Not intending to be limited by theory, the authors believe that the addition of a surfactant causes competition for those centers of cellulose on which the studied fluid is absorbed. Thus, when a surfactant is excessively substantial, it reacts with an excessively large number of centers, reducing the absorption capacity of the fiber.

As used herein, the specific absorption rate is measured according to method SCAN-C-33: 80, which was approved by the Scandinavian Committee for the Study of Pulp, Paper and Cardboard. As a rule, this method is carried out as follows. First, a sample is made using the PFI gasket manufacturing apparatus. The vacuum is turned on and approximately 3.01 g of fluff pulp is introduced into the inlet of the gasket manufacturing apparatus. The vacuum is turned off, the test sample is removed and placed on the scale to measure the mass of the gasket. Set the mass of fluff pulp at 3.00 ± 0.01 g and record it as a dry mass. The fluff pulp is placed in the measuring cylinder. A cylinder containing fluff pulp is placed in a shallow perforated cup of an absorption meter and a water tap is opened. Carefully set the load weighing 500 g on a pad of fluff pulp, while lifting the measuring cylinder, and immediately press the start button. The meter works for 30 seconds before the display shows 00.00. When the display shows 20 seconds, the height of the dry pad is measured with an accuracy of 0.5 mm (dry height). When the display shows 00.00 again, press the start button again to quickly bring up the tray to automatically raise the water, and then write down the time on the display (absorption time, T). The meter will continue to operate for 30 seconds. The water tray automatically lowers, and another 30 seconds pass. When the display shows 20 seconds, record the height of the wet pad with an accuracy of 0.5 mm (wet height). The sample holder is removed, the wet pad is transferred onto the balance to measure the wet mass, and the water tap is closed. The specific absorption rate (s / g) is calculated as T / dry weight. Specific capacity (g / g) is calculated as (wet weight - dry weight) / dry weight. The wet volume (cm ³ / g) is calculated as [19.64 cm ² × wet height / 3] / 10. Dry volume is calculated as [19.64 cm ² × dry height / 3] / 10. The comparative standard for comparison with a fiber treated with a surfactant is an identical fiber without the addition of a surfactant.

As a rule, it is believed that softeners and disintegrants are often commercially available only as complex mixtures, and not as individual compounds. Although the following discussion will focus on the predominant substances, it should be understood that in practice, commercially available mixtures are generally used. Suitable emollients, disintegrants and surfactants are well known to those skilled in the art and are described in detail in the literature.

Suitable surfactants include cationic surfactants, anionic surfactants and nonionic surfactants that are not essential to the fiber. In one embodiment, the surfactant is a nonionic surfactant. In one embodiment, the surfactant is a cationic surfactant. In one embodiment, the surfactant is a plant derived surfactant, such as a plant derived fatty acid, including a quaternary ammonium salt of a plant derived fatty acid. Such connections include DB999 and DB1009, which are supplied by Cellulose Solutions. Other surfactants may include, but are not limited to, the ethoxylated nonylphenol ether Berol 388 from Akzo Nobel.

Biodegradable softeners may be used. Exemplary biodegradable cationic softeners / disintegrants are described in US Pat. These compounds are biodegradable quaternary ammonium diesters, quaternized amino esters, and biodegradable esters derived from vegetable oil functionalized with quaternary ammonium chloride and diester dierucyl dimethyl ammonium chloride and are examples of biodegradable softeners.

Surfactant is added in amounts up to 8 pounds per ton, including from 2 pounds per ton to 7 pounds per ton, including from 4 pounds per ton to 7 pounds per ton, including from 6 pounds per ton up to 7 pounds per ton.

A surfactant can be added at any point before rolls, bales or pulp sheets are made. According to one embodiment, the surfactant is added directly in front of the pressurized pressurization tank, in particular at the inlet of the primary feed pump of the cleaning device.

According to one embodiment of the present invention, the fiber has an improved filtration capacity compared to the same fiber without the addition of a surfactant when used in a viscose process. For example, the filtration capacity of a viscose solution containing a fiber according to the present invention is at least 10% less, including at least 15% less, including at least 30% less including at least 40% less than the filtration capacity of a viscose solution made in the same way from an identical fiber without a surfactant. The filtration ability of a viscose solution is measured in the following way. The solution is placed in a tank containing nitrogen under a pressure of 27 psi (0.1862 MPa) and having a bottom filter hole with a diameter of 1 and 3/16 inch (3.01625 cm). The filtering device consists of the following elements from the outside into the tank: a perforated metal disk, a stainless steel mesh with a mesh size of 20 mesh (0.853 mm), muslin cloth, Whatman 54 filter paper and a two-layer dense flannel with a fleecy side facing the contents of the tank. For 40 minutes, the solution is filtered through a filter device, and then for the next 140 minutes (so that t = 0 at the time of 40 minutes), the volume (mass) of the filtered solution over time (coordinate X) and the mass of filtered viscose (coordinate Y), and the slope of the resulting graph is the filtering number. Results are recorded at intervals of 10 minutes. A comparable standard for comparison with a fiber treated with a surfactant is an identical fiber without the addition of a surfactant.

According to one embodiment of the present invention, the surfactant treated fiber of the present invention exhibits a limited increase in specific absorption rate of, for example, less than 30%, while at the same time a decrease in filtration capacity of, for example, at least 10%. According to one embodiment, a fiber treated with a surfactant exhibits an increase in specific absorption rate of less than 30% and a decrease in filtration capacity of at least 20%, including at least 30%, including at least 40%. According to yet another embodiment, the fiber treated with the surfactant exhibits an increase in specific absorption rate of less than 25% and a decrease in filtration capacity of at least 10%, including at least about 20% , including at least 30%, including at least 40%. According to a further embodiment, the fiber treated with the surfactant exhibits an increase in specific absorption rate of less than 20% and a decrease in filtration capacity of at least 10%, including at least about 20% , including at least 30%, including at least 40%. According to another embodiment, the fiber treated with the surfactant exhibits an increase in the specific absorption rate of less than 15% and a decrease in filtration capacity of at least 10%, including at least about 20 %, including at least 30%, including at least 40%. According to a further embodiment, the fiber treated with a surfactant has an increase in specific absorption rate of less than 10% and a decrease in filtration capacity of at least 10%, including at least about 20% , including at least 30%, including at least 40%.

To date, the incorporation of a cationic surfactant into the cellulose used to make viscose has been considered detrimental to the manufacture of viscose. Cationic surfactants are attached to the same centers of cellulose with which alkali must react in order for the decomposition of the cellulose fiber to begin. Thus, it has long been believed that cationic materials should not be used for the pretreatment of cellulose in the case of fibers used in the manufacture of viscose. Not intending to be limited by theory, the authors believe that since the fibers made according to the present invention differ from the prior art fibers in their form, nature and chemistry, the cationic surfactant does not bind in the same way as it binds to the prior art fibers. When the fibers of the present invention are treated with the surfactant of the present invention, the fibers are separated so as to improve alkali penetration and filtering ability. Thus, according to one embodiment of the present invention, fibers can be used as a replacement for expensive cotton or sulphite fibers to a greater extent than untreated or prior art fiber.

The incorporation of a surfactant into a fiber according to the present invention improves the performance of a fiber made from fluff pulp. In particular, a surfactant can reduce the number of nodes that can be formed between the fibers, and thus, manufacturing of the product by pneumatic stacking or pneumoforming is improved. The surfactant also improves the structure of the fluff pulp product. Since the fibers exhibit reduced affinity for each other, aggregate formation is reduced. In addition, a decrease in the number of nodes also leads to a reduction in energy consumption during fiber separation and cellulose fluffing.

The use of a surfactant also affects the physical characteristics of products made from treated fiber. Fiber containing a surfactant or disintegrant will exhibit a decrease in tensile strength of the mesh and an improvement in embossability. A side effect of using a surfactant to treat the fibers to be used in absorbent articles is that the surfactant can reduce the number of centers suitable for hydrogen bonding, and thus reduces the rate of water absorption and the total capacity.

The present invention also provides a method for reducing odor, such as the smell of body secretions, such as the smell of urine or blood. According to some embodiments of the present invention, there is provided a method for controlling an odor comprising producing a modified bleached sulfate fiber according to the present invention and applying a flavoring agent to a bleached sulfate fiber so that the amount of flavoring agent in the atmosphere is reduced compared to the amount of flavoring agent in the atmosphere after applying an equivalent amount of flavoring agent to an equivalent tape mass of standard sulfate fiber. According to some embodiments of the present invention, there is provided a method for controlling odor, comprising inhibiting the bacterial formation of odor. According to some embodiments of the present invention, there is provided a method for controlling odor comprising absorbing flavoring agents, such as nitrogenous flavoring agents, on a modified sulfate fiber. As used herein, the term “nitrogenous flavoring agents” is to be understood as meaning flavoring substances in the molecules of which contain at least one nitrogen atom.

According to at least one embodiment, the method of reducing odor comprises making a modified cellulosic fiber according to the present invention and applying a flavoring agent, such as a nitrogenous compound, for example ammonia, or microorganisms that are capable of producing a nitrogenous compound, onto a modified sulfate fiber. According to some embodiments, the method further comprises making fluff pulp from the modified cellulose fiber before applying the flavoring agent to the modified sulfate fiber. In some embodiments, the flavoring agent contains bacteria of at least one species that are capable of producing nitrogen compounds. In some embodiments, the flavoring agent contains nitrogen compounds, such as ammonia.

In some embodiments, the odor reduction method further comprises absorbing ammonia on the modified cellulose fiber. In some embodiments, the odor reduction method further comprises inhibiting the bacterial production of ammonia. In some embodiments, a method of inhibiting the bacterial production of ammonia comprises inhibiting the growth of bacteria. In some embodiments, a method of inhibiting the bacterial production of ammonia comprises inhibiting bacterial synthesis of urea.

According to some embodiments, the odor reduction method comprises combining the modified cellulose fiber and at least one odor reducing agent and then applying a flavoring agent to the modified cellulose fiber combined with the odor reducing agent.

Exemplary odor control agents are known in the art and include, for example, odor reducing agents, odor masking agents, biocides, enzymes and urease inhibitors. For example, a modified cellulose fiber can be combined with at least one odor control substance, which is selected as zeolites, activated carbon, diatomaceous earth, cyclodextrins, clay, chelating agents, such as substances containing metal ions, such as copper ions, silver or zinc, ion exchange resins, antibacterial or antimicrobial polymers and / or flavors.

In some embodiments, at least one superabsorbent polymer (SAP) is combined with a modified cellulosic fiber. In some embodiments, the SAP may be an odor control agent. Examples of SAP that can be used in accordance with the present invention include, but are not limited to, Hysorb ™, which is sold by BASF, Aqua Keep®, which is sold by Sumitomo, and FAVOR®, which is sold by Evonik.

II. Sulfate fibers

This document refers to "standard," ordinary "or" traditional "sulphate fibers, sulphate bleached fibers, sulphate pulp or sulphate bleached pulp. Such fibers or cellulose are often described as a starting point for determining the improved properties of the materials of the present invention. As used herein, these terms are used interchangeably and mean fibers or cellulose that are identical in composition and treated in the same way as specified fibers or cellulose without undergoing any oxidation, including separately or before one or more alkali treatment procedures. or acid (i.e., processed in a standard or traditional way). As used herein, the term “modified” means a fiber that undergoes an oxidative treatment, including separately or before one or more alkali or acid treatment procedures.

The physical characteristics (eg, fiber length and viscosity) of the modified cellulose fiber, which are referred to in the present description, are measured in accordance with the protocols presented in the "Examples" section.

The present invention provides a sulfate fiber having a low and ultra low viscosity. Unless otherwise specified, the term “viscosity,” as used herein, means the viscosity of a 0.5% solution measured by the capillary method using CED according to the TAPPI T230-om99 procedure, as presented in the protocols. The modified sulfate fiber according to the present invention exhibits unique characteristics that are indicative of chemical modifications made to the fiber. More specifically, the fiber according to the present invention exhibits characteristics that are similar to those of a standard sulfate fiber, such as length and degree of milling, but it also exhibits some very distinct characteristics that determine the increase in the number of functional groups contained in the modified fiber. This modified fiber exhibits unique characteristics when it is subjected to the aforementioned TAPPI test for viscosity measurement. In particular, in the aforementioned TAPPI study, an alkaline substance acts on the fiber as part of the research method. The effect of alkali on the modified fiber, as described above, causes the modified fiber to hydrolyze in a different way than standard sulfate fiber, and thus the measured viscosity is generally lower than the viscosity of standard sulfate fiber. Accordingly, one skilled in the art should understand that the viscosity measurement method may influence the measured viscosity values. For the purposes of the present invention, the viscosity values that are referred to herein as measured by the aforementioned TAPPI method are the sulfate fiber viscosity used to calculate the degree of fiber polymerization.

Unless otherwise specified, the term “degree of polymerization,” as used herein, means the weight average degree of polymerization (DPw) calculated from capillary measurements using the CED viscosity of a 0.5% solution according to TAPPI T230-om99. See, for example, Cellucon Conference on the Chemistry and Processing of Wood and Plant Fiber Materials, 1994, Study Protocol 8, p. 155, ed. J. F. Kennedy et al., Woodhead Publishing Ltd., Abington Hall, Abinton, Cambridge, CBI 6AH, England. The term "low degree of polymerization" refers to a degree of polymerization of from about 1160 to about 1860, or a viscosity of from about 7 to about 13 mPa · s. The term "ultra-low polymerization fibers" refers to fibers in which the polymerization degree is from about 350 to about 1160, or the viscosity is from about 3 to about 7 mPa.s.

Not intending to be limited by theory, the authors believe that the fiber according to the present invention characterizes the artificial degree of polymerization, when the degree of polymerization is calculated by measuring the viscosity using CED according to the TAPPI method T230-om99. In particular, the authors believe that the catalytic oxidative treatment of the fiber according to the present invention does not destroy the cellulose to the extent shown by the measured degree of polymerization, but instead, the effect of opening bonds and introducing substituents that make the cellulose more reactive and the cellulose chain is largely manifested. not destroyed. In addition, the authors believe that the TAPPI T230-om99 CED viscosity study, which begins with the addition of alkali, produces the effect of breaking the cellulose chain in the new reaction centers, and as a result a cellulose polymer that has a significantly larger number of short segments than were present in the fiber in the state before the study. This is confirmed by the fact that the fiber length does not change significantly during the manufacturing process.

In some embodiments, the modified cellulose fiber has a polymerization degree of from about 350 to about 1860. In some embodiments, the polymerization degree is from about 710 to about 1860. In some embodiments, the polymerization degree is from about 350 to about 910. In some embodiments, the degree of polymerization is from about 350 to about 1160. According to ome embodiments, the degree of polymerization is from about 1160 to about 1860. In some embodiments, the degree of polymerization is less than 1860, less than 1550, less than 1300, less than 820 or less than 600.

In some embodiments, the modified cellulosic fiber has a viscosity of about 3.0 mPa.s. to about 13 mPa.s. In some embodiments, the viscosity is from about 4.5 mPa⋅s to about 13 mPa⋅s. In some embodiments, the viscosity is from about 3.0 mPa · s to about 5.5 mPa · s. In some embodiments, the viscosity is from about 3.0 mPa · s to about 7 mPa · s. In some embodiments, the viscosity is from about 7 mPa.s to about 13 mPa.s In some embodiments, the viscosity is less than 13 mPa⋅s, less than 10 mPa⋅s, less than 8 mPa⋅s, less than 5 mPa⋅s, or less than 4 mPa⋅s.

According to some embodiments of the present invention, the modified sulfate fiber retains its degree of grinding during the bleaching process. In some embodiments, the modified cellulosic fiber has a “milling degree” of at least about 690 ml, for example at least about 700 ml, or about 710 ml, or about 720 ml, or about 730 ml.

According to some embodiments of the present invention, the modified sulfate fiber According to some embodiments, the modified sulfate fiber retains its fiber length during the bleaching process.

In some embodiments, when the modified cellulosic fiber is coniferous fiber, the modified cellulosic fiber has an average fiber length that is measured in accordance with study protocol 12, as described in the Examples section below, and which is approximately 2 mm or more. In some embodiments, the average fiber length is not more than about 3.7 mm. In some embodiments, the average fiber length is at least about 2.2 mm, about 2.3 mm, about 2.4 mm, about 2.5 mm, about 2.6 mm, about 2.7 mm, approximately 2.8 mm, approximately 2.9 mm, approximately 3.0 mm, approximately 3.1 mm, approximately 3.2 mm, approximately 3.3 mm, approximately 3.4 mm, approximately 3.5 mm, approximately 3 6 mm or approximately 3.7 mm. In some embodiments, the average fiber length is from about 2 mm to about 3.7 mm, or from about 2.2 mm to about 3.7 mm.

In some embodiments, when the modified cellulosic fiber is hardwood fiber, the modified cellulosic fiber has an average fiber length of about 0.75 to about 1.25 mm. For example, the average fiber length may be at least about 0.85 mm, including about 0.95 mm, or about 1.05 mm, or about 1.15 mm.

According to some embodiments of the present invention, the modified sulfate fiber has a whiteness equivalent to that of a standard sulfate fiber. In some embodiments, the modified cellulosic fiber has a whiteness of at least 85, 86, 87, 88, 89, or 90 according to the ISO standard. In some embodiments, the whiteness is no more than about 92. In some embodiments, the whiteness is from about 85 to about 92, or from about 86 to about 90, or from about 87 to about 90, or from about 88 to about 90 .

According to some embodiments of the present invention, the modified cellulosic fiber is more compressible and / or embossable than standard sulfate fiber. In some embodiments, the modified cellulosic fiber can be used to make structures that are thinner and / or higher in density than structures made using equivalent amounts of standard sulfate fiber.

According to some embodiments of the present invention, the modified cellulosic fiber can be compressed to a density of at least about 0.21 g / cm ³ , for example, about 0.22 g / cm ³ , or about 0.23 g / cm ³ , or approximately 0.24 g / cm ³ . According to some embodiments of the present invention, the modified cellulosic fiber can be compressed to a density of about 0.21 to about 0.24 g / cm ³ . According to at least one embodiment, the modified cellulosic fiber of the present invention at a gauge compression pressure of 20 psi (0.1379 MPa) has a density of from about 0.21 to about 0.24 g / cm ³ .

According to some embodiments of the present invention, the modified cellulosic fiber at a gauge compression pressure of about 5 psi (0.03447 MPa) has a density of about 0.110 to about 0.114 g / cm ³ . For example, the modified cellulosic fiber according to the present invention at a gauge compression pressure of approximately 5 psi (0.03447 MPa) may have a density of at least about 0.110 g / cm ³ , for example at least about 0.112 g / cm ³ , or about 0.113 g / cm ³ , or about 0.114 g / cm ³ .

According to some embodiments of the present invention, the modified cellulosic fiber at a gauge compression pressure of about 10 psi (0.06895 MPa) has a density of about 0.130 to about 0.155 g / cm ³ . For example, the modified cellulose fiber according to the present invention at a gauge compression pressure of approximately 10 psi (0.06895 MPa) may have a density of at least about 0.130 g / cm ³ , for example at least about 0.135 g / cm ³ , or about 0.140 g / cm ³ , or about 0.145 g / cm ³ , or about 0.150 g / cm ³ .

According to some embodiments of the present invention, the modified cellulosic fiber can be compressed to a density of at least about 8% more than the density of a standard sulfate fiber. According to some embodiments of the present invention, the modified cellulose fiber has a density that is higher than the density of a standard sulfate fiber, and the corresponding difference is from about 8% to about 16%, for example, from about 10% to about 16%, or from about 12% to about 16%, or from about 13% to about 16%, or from about 14% to about 16%, or from about 15% to about 16%.

According to some embodiments of the present invention, the modified sulfate fiber has an increased content of carboxyl groups relative to standard sulfate fiber.

In some embodiments, the modified cellulose fiber has a carboxyl group content of about 2 meq / 100 g to about 9 meq / 100 g. In some embodiments, the carboxy group content is about 3 meq / 100 g to about 8 meq / 100 g. In some embodiments, the carboxyl group content is about 4 meq / 100 g. In some embodiments, the carboxyl group content is, p at least about 2 meq / 100 g, for example at least about 2.5 meq / 100 g, for example at least about 3.0 meq / 100 g, for example at least about 3, 5 meq / 100 g, for example at least about 4.0 meq / 100 g, for example at least about 4.5 meq / 100 g, or, for example, at least about 5.0 meq / 100 g

The modified sulfate fiber according to the present invention has an increased content of aldehyde groups with respect to standard bleached sulfate fiber. In some embodiments, the modified sulfate fiber has an aldehyde group content of about 1 meq / 100 g to about 9 meq / 100 g. In some embodiments, the aldehyde group content is at least about 1.5 meq / 100 g, approximately 2 meq / 100 g, approximately 2.5 meq / 100 g, approximately 3.0 meq / 100 g, approximately 3.5 meq / 100 g, approximately 4.0 meq / 100 g, approximately 4.5 meq / 100 g, or approximately 5.0 meq / 100 g, or at least approximate at least 6.5 meq, or at least about 7.0 meq.

In some embodiments, the modified cellulosic fiber has a ratio of total aldehyde groups to carboxyl groups of more than about 0.3, including more than about 0.5, including more than about 1, including more than approximately 1.4. in some embodiments, the ratio of the total content of aldehyde groups to the content of carboxyl groups is from about 0.3 to about 1.5. In some embodiments, the ratio is from about 0.3 to about 0.5. In some embodiments, this ratio is from about 0.5 to about 1. In some embodiments, this ratio is from about 1 to about 1.5.

In some embodiments, the modified sulfate fiber has a higher bending and crimping index than standard sulfate fiber. The modified sulfate fiber of the present invention has a bending index in the range of about 1.3 to about 2.3. For example, the bend index may range from about 1.5 to about 2.3, or from about 1.7 to about 2.3, or from about 1.8 to about 2.3, or from about 2.0 to about 2,3. The modified sulfate fiber of the present invention may have a length-weighted crimp index of about 0.11 to about 0.23, including from about 0.15 to about 0.2.

In some embodiments, the crystallinity index of the modified sulfate fiber is reduced, and this decrease is from about 5% to about 20%, for example, from about 10% to about 20%, or from about 15% to about 20% with respect to the crystallinity index standard sulfate fiber.

In some embodiments, the modified cellulose of the present invention has an R10 value of from about 65% to about 85%, for example, from about 70% to about 85%, or from about 75% to about 85%. In some embodiments, the modified fiber of the present invention has an R18 value of from about 75% to about 90%, for example, from about 80% to about 90%, for example, from about 80% to about 87%. The values of R18 and R10 are described in the TAPPI 235 method. The value of R10 represents the content of residual undissolved material that remains after the extraction of cellulose with a solution containing 10 wt. % alkali, and the value of R18 represents the content of residual undissolved material, which remains after the extraction of cellulose with a solution containing 18 wt. % alkali. Typically, in a 10% alkaline solution, hemicellulose and chemically broken short chain cellulose are dissolved and removed in solution. On the other hand, as a rule, only hemicellulose is dissolved and removed in an 18% alkaline solution. Thus, the difference between the R10 value and the R18 value (R = R18 - R10) represents the number of chemically broken short pulp chains that are present in the cellulose sample.

Based on one or more of the aforementioned properties, such as an index of fiber bending and crimping, an increase in functional groups and a degree of crystallinity of the modified sulfate fiber, one skilled in the art may assume that the modified sulfate fiber of the present invention will have certain characteristics that the standard does not have sulfate fiber. For example, the authors believe that the sulfate fiber according to the present invention may be more flexible than standard sulfate fiber, and may also stretch and / or bend and / or exhibit elasticity and / or increased capillarity. In addition, not intending to be limited by theory, the authors suggest that the modified sulfate fiber can create a physical structure, for example, in fluffy cellulose, which will cause the fibers to weave and form bonds between the fibers, or weave materials attached to the cellulose so that these the materials will occupy a relatively fixed spatial position in the cellulose volume, which delays their dispersion. In addition, it is assumed, at least due to the reduced crystallinity with respect to standard sulfate fiber, that the modified sulfate fiber according to the present invention will be softer than standard sulfate fiber, which increases its applicability in the manufacture of absorbent products, such as diapers and dressings materials.

In some embodiments, the modified cellulosic fiber has an alkali solubility S10 of about 16% to about 30%, or from about 14% to about 16%. In some embodiments, the modified cellulosic fiber has an S18 alkali solubility of from about 14% to about 22%, or from about 14% to about 16%. In some embodiments, the modified cellulose fiber has an ΔR (difference between S10 and S18) of about 2.9 or more. In some embodiments, the difference ΔR is about 6.0 or more.

In some embodiments, the modified cellulosic strength of a fiber, the measure of which is the breaking length in the wet state at zero distance between the clamps, is from about 4 km to about 10 km, for example, from about 5 km to about 8 km. In some embodiments, the fiber strength is at least about 4 km, about 5 km, about 6 km, about 7 km, or about 8 km. In some embodiments, the fiber strength is from about 5 km to about 7 km, or from about 6 km to about 7 km.

In some embodiments, the modified sulfate fiber has odor control properties. In some embodiments, the modified sulfate fiber is able to reduce the smell of body excretions such as urine or menstrual blood. In some embodiments, the modified sulfate fiber absorbs ammonia. In some embodiments, the modified sulfate fiber inhibits odor formation by bacteria, for example, in some embodiments, the modified sulfate fiber inhibits bacterial production of ammonia.

According to at least one embodiment, the modified sulfate fiber is capable of absorbing flavoring agents, such as nitrogen-containing flavoring agents, for example, ammonia.

As used herein, the term “odor producing” is to be understood as meaning a chemical material that has a smell or aroma, or that is capable of interacting with olfactory receptors, or that term refers to microorganisms, such as bacteria, that are capable of forming compounds that produce an odor or aroma, for example, the bacteria that make urea.

In some embodiments, the modified sulphate fiber reduces the concentration of ammonia in the atmosphere more than the standard bleached sulphate fiber reduces the concentration of ammonia in the atmosphere. For example, a modified sulfate fiber can reduce the concentration of ammonia in the atmosphere by absorbing at least a portion of the ammonia sample deposited on the modified sulfate fiber, or by inhibiting the bacterial production of ammonia. According to at least one embodiment, the modified sulfate fiber absorbs ammonia and inhibits the bacterial production of ammonia.

According to some embodiments, the modified sulfate fiber reduces the concentration of ammonia in the atmosphere by at least about 40% more than standard sulfate fiber, for example, at least about 50% more, or about 60% more, or about 70% more, or about 75% more, or about 80% more, or about 90% more than standard sulfate fiber.

According to some embodiments of the present invention, the modified sulfate fiber after applying 0.12 g of a solution of 50% ammonium hydroxide to about 9 g of modified cellulose and incubating for 45 minutes reduces the concentration of ammonia in the atmosphere in a volume of 1.6 l to less than 150 parts per million, for example, less than about 125 parts per million, for example, less than about 100 parts per million, for example, less than about 75 parts per million, for example, less than about 50 parts per million and a million.

In some embodiments, the modified sulfate fiber absorbs from about 5 to about 10 ppm ammonia per gram of fiber. For example, modified cellulose can absorb from about 6 to about 10 parts per million, or from about 7 to about 10 parts per million, or from about 8 to about 10 parts per million ammonia per gram of fiber.

In some embodiments, the modified sulfate fiber simultaneously has improved odor limiting properties and improved whiteness compared to standard sulfate fiber. According to at least one embodiment, the modified cellulosic fiber has a whiteness of from about 85 to about 92, and an odor reducing ability. For example, modified cellulose can have a whiteness of from about 85 to about 92, and absorbs from about 5 to about 10 parts per million ammonia per 1 g of fiber.

In some embodiments, the modified cellulosic fiber has a cytotoxicity assay of isolating a minimum support medium according to ISO 10993-5 of less than 2 on a scale of 0 to 4 points. For example, cytotoxicity may be less than about 1.5, or less than about 1.

It is known that oxidized cellulose, in particular cellulose, which contains aldehyde and / or carboxyl groups, exhibits antiviral and / or antimicrobial activity. See, for example, Song et al., “New Antiviral Activity of Dialdehyde Starch,” Electronic J. Biotech., 2009, v. 12, No. 2; U.S. Patent No. 7019191 (Looney et al.). For example, aldehyde groups in dialdehyde starch are known to provide antiviral activity, and oxidized cellulose and oxidized regenerated cellulose, for example, containing carboxyl groups, are often used in wound care products, in particular due to their bactericidal and hemostatic properties. Accordingly, according to some embodiments of the present invention, cellulosic fibers can exhibit antiviral and / or antimicrobial activity. According to at least one embodiment, the modified cellulosic fiber exhibits antibacterial activity. In some embodiments, the modified cellulose fiber exhibits antiviral activity.

According to some embodiments of the present invention, the modified sulfate fiber has an aligned polymerization degree of less than 200, including less than about 100, or less than about 80, or less than about 75, or less than about 50, or not more than about 48. The aligned degree of polymerization can be measured by methods known in the art, for example, by the methods described in Battista et al., “Aligned degree of polymerization”, the whole chemistry section yulozy Symposium on the decomposition of cellulose and cellulose derivatives, a collection of 127, American Chemical Society (the ACS), Cincinnati (Ohio, USA), March-April 1955

In some embodiments, the modified sulfate fiber has a permanganate number of less than about 2. For example, the modified sulfate fiber can have a permanganate number of less than about 1.9. In some embodiments, the modified sulfate fiber has a permanganate number of about 0.1 to about 1, including about 0.1 to about 0.9, including about 0.1 to about 0.8, for example from about 0.1 to about 0.7, for example, from about 0.1 to about 0.6, including from about 0.1 to about 0.5, or from about 0.2 to about 0.5 .

In some embodiments, the modified sulphate fiber is a sulphate fiber that has been bleached in a multi-stage process in which at least one bleaching step is performed after the oxidation step. According to such embodiments, the modified fiber after at least one bleaching step has a “permanganate number”, measured according to the TAPPI UM 25 application method, from about 0.2 to about 1.2. For example, the permanganate number may range from about 0.4 to about 1.2, or from about 0.6 to about 1.2, or from about 0.8 to about 1.2, or from about 1.0 to approximately 1.2.

In some embodiments, the modified cellulosic fiber has a copper number of more than about 2. In some embodiments, the copper number is more than 2.0. In some embodiments, the copper number is more than about 2.5. For example, the copper number may be more than about 3. According to some embodiments, the copper number is from about 2.5 to about 5.5, including from about 3 to about 5.5, for example, from about 3 to about 5 , 2.

According to at least one embodiment, the hemicellulose content of the modified sulfate fiber is substantially the same as that of a standard unbleached sulfate fiber. For example, the hemicellulose content of coniferous sulfate fiber may range from about 16% to about 18%. For example, the hemicellulose content of hardwood sulphate fiber can range from about 18% to about 25%.

III. Subsequent treatment - hydrolysis in acid / alkaline medium

According to some embodiments of the present invention, the modified sulfate fiber is suitable to produce cellulose derivatives, for example, to produce low viscosity cellulose ethers, cellulose esters, and microcrystalline cellulose. According to some embodiments of the present invention, the modified sulfate fiber is a hydrolyzed modified sulfate fiber. As used herein, the terms “hydrolyzed modified sulfate fiber”, “hydrolyzed sulfate fiber” and similar terms are to be understood as meaning a fiber that has been hydrolyzed during any treatment in an acidic or alkaline medium in which cellulosic depolymerization is known. chain. According to some embodiments of the present invention, the sulfate fiber is subjected to further processing to reduce its viscosity and / or degree of polymerization. For example, the sulfate fiber of the present invention can be treated with an acid or a base.

According to some embodiments of the present invention, there is provided a method for treating a sulfate fiber, comprising bleaching the sulfate fiber of the present invention, and then hydrolyzing the bleached sulfate fiber. Hydrolysis can be carried out by any method known to those of ordinary skill in the art. In some embodiments, the bleached sulfate fiber is hydrolyzed by at least one acid. In some embodiments, the bleached sulfate fiber is hydrolyzed with acid, which is selected as sulfuric acid, hydrochloric acid and other mineral acids.

The present invention also provides a method for the manufacture of cellulose ethers according to some embodiments, wherein the method for the manufacture of cellulose ethers includes bleaching a sulfate fiber according to the present invention, treating the bleached sulfate fiber with at least one alkaline substance such as sodium hydroxide, and introducing the fibers into a reaction with at least one ether forming substance.

The present invention also provides methods for making cellulose esters. According to some embodiments, the method of manufacturing cellulose esters involves bleaching a sulfate fiber in accordance with the present invention, treating the bleached sulfate fiber with a catalyst such as sulfuric acid, and subsequently treating the fiber with at least one acetic anhydride or acetic acid material. According to an alternative embodiment, the method of manufacturing cellulose acetate involves bleaching a sulfate fiber in accordance with the present invention, hydrolyzing the bleached sulfate fiber with sulfuric acid, and treating the hydrolyzed sulfate fiber with at least one substance, which is acetic anhydride or acetic acid.

The present invention also provides methods for making microcrystalline cellulose. According to some embodiments, a method for producing microcrystalline cellulose comprises the manufacture of a bleached sulfate fiber according to the present invention, hydrolysis of the bleached sulfate fiber with at least one acid to achieve the desired degree of polymerization or while approaching an equalized degree of polymerization. According to a further embodiment, the hydrolyzed bleached sulphate fiber is machined in which, for example, milling, grinding or shearing is performed. Techniques for machining hydrolyzed sulfate fibers in the manufacture of microcrystalline cellulose are known to those skilled in the art and can provide the desired particle sizes. Other parameters and manufacturing conditions of microcrystalline cellulose are also known, and they are described, for example, US patent No. 2978446 and No. 5346589.

According to some embodiments of the present invention, the modified sulfate fiber is further processed using a caustic or alkaline substance to reduce the viscosity and / or degree of polymerization of the fiber. Alkaline treatment at a pH of more than about 9 causes dialdehydes to react and undergo beta-hydroxyl elimination. This further modified fiber, which is treated with an alkaline substance, may also be suitable for use in the manufacture of tissue paper, towels and other absorbent products, as well as in the manufacture of cellulose derivatives. In more traditional paper manufacturing, strength-enhancing substances are often added to the fiber slurry to modify the physical properties of the final products. This alkali-modified fiber can be used to replace some or all of the strength-regulating substances used in the manufacture of tissue paper and towels.

As described above, there are three types of fibrous products that can be manufactured by carrying out the processes described herein. The first type is a fiber that is processed by catalytic oxidation, and this fiber is almost impossible to distinguish from its traditional counterpart (when at least the physical characteristics and properties of paper production are considered), and yet it contains functional groups associated with it which give it one or more of its properties, including odor limitation, compressibility, low and ultra low degree of polymerization, and / or the ability to transform "n spot "having a low degree of polymerization / low viscosity in the fiber hydrolysis in alkaline or acidic medium, such as the conditions of manufacture of cellulose derivatives, such as the manufacture of ethers or acetates. The physical characteristics and properties of the production of paper from this type of fiber make it suitable for use in typical paper production and the manufacture of absorbent products. On the other hand, an increase in the content of functional groups, for example, aldehyde and carboxyl groups, as well as properties associated with these functional groups, make this fiber more desirable and more versatile than standard sulfate fiber.

The second type of fiber is a fiber that has been catalytically oxidized and then treated with a caustic or alkaline substance. An alkaline substance causes the fiber to break down at the points of the carbonyl functional groups that were introduced during the oxidation process. This fiber has different physical characteristics and paper production properties compared to a fiber that has only been oxidized, but it can exhibit the same or similar degree of polymerization as a result of the study used to measure the viscosity and therefore the degree of polymerization when the fiber is exposed alkaline substance. It will be apparent to those skilled in the art that various alkaline substances and their levels may provide different degrees of polymerization.

A third type of fiber is a fiber that has been catalytically oxidized and then processed in an acid hydrolysis step. As a result of acid hydrolysis, the fiber decomposes, possibly to levels to which its aligned degree of polymerization corresponds.

IV. Products made from sulfate fibers

The present invention provides products made from a modified sulfate fiber, which is described herein. In some embodiments, the articles are typically articles made from standard sulfate fiber. According to other embodiments, the articles are typically articles made from cotton fluff or sulphite pulp. More specifically, the modified fiber according to the present invention can be used, without further modification, in the manufacture of absorbent articles and as a starting material in the manufacture of chemical derivatives such as ethers and esters. To date, there has been no fiber that is suitable for use in place of a high alpha isomer of cellulose, such as cotton and sulphite cellulose, as well as traditional sulphate fiber.

Expressions such as “which can replace cotton fluff (or sulfite cellulose)” and “interchangeable with cotton fluff (or sulfite cellulose)” and “which can be used instead of cotton fluff (or sulfite cellulose)” and similar expressions only mean that fiber has properties suitable for use in finished products, which are usually made using cotton fluff (or sulphite pulp). These expressions are not intended to indicate that the fiber necessarily has all the same characteristics as cotton fluff (or sulphite pulp).

According to some embodiments, the articles are absorbent articles, including but not limited to medical devices, including wound care products (e.g., dressings), baby diapers and diapers, adult incontinence products, feminine hygiene products, including, for example , sanitary pads and tampons, pneumatically laid non-woven products, pneumatically laid composite products, “table” wipes, scarves, towels, thin paper products, etc. Absorbent Elia according to the present invention may be disposable. According to such embodiments of the present invention, the modified fiber can be used as a complete or partial replacement for bleached hardwood or coniferous fiber, which is typically used in the manufacture of these products.

In some embodiments, the modified cellulose fiber is present in the form of fluff pulp and has one or more properties that make the modified cellulose fiber more effective than conventional fluff pulp in absorbent articles. More specifically, the modified fiber of the present invention can have improved compressibility and improved odor control, both of which make it desirable as a substitute for the currently fluff pulp fiber. Due to the improved compressibility of the fiber according to the present invention, it is suitable for use according to the embodiments, the task of which is to produce more compact absorbent products of reduced thickness. One of ordinary skill in the art, understanding the compressible nature of the fiber of the present invention, can easily develop absorbent products in which the fiber can be used. By way of example, according to some embodiments of the present invention, there is provided an ultrathin hygiene article comprising modified sulfate fibers of the present invention. The ultra-thin fluffy core is typically used, for example, to make feminine hygiene products or baby diapers. Other products that can be manufactured using the fiber of the present invention may be products that require an absorbent core or a compressed absorbent layer. When compressed, the fiber of the present invention exhibits zero or negligible absorption loss, but provides improved flexibility.

The modified fiber of the present invention can also be used without further modification in the manufacture of absorbent products, including, but not limited to, tissue paper, towels, napkins, and other paper products that are manufactured by a conventional paper machine. Traditional papermaking processes include the manufacture of an aqueous suspension of fibers, which are typically deposited on a forming wire, and then water is removed. An increase in the content of functional groups in the modified cellulose fibers according to the present invention can provide products having improved characteristics when the products contain these modified fibers. For the reasons discussed above, the modified fiber according to the present invention can lead to the fact that products made from it exhibit increased strength, which is likely due to an increase in the content of functional groups in the fibers. The modified fiber of the present invention may also contribute to the manufacture of articles having improved softness.

According to some embodiments of the present invention, the modified fiber without further modification can be used in the manufacture of ethers (e.g. carboxymethyl cellulose) and cellulose esters to replace fiber having a very high degree of polymerization, comprising from about 2950 to about 3980 (i.e. fiber whose viscosity of a 0.5% solution, measured by capillary method using CED, is from about 30 mPa⋅s to about 60 mPa⋅) and is very high e cellulose content percentage (e.g., 95% or more), such as a fiber produced from cotton linters, and bleached softwood fibers manufactured in the process of sulphite pulp treatment in an acidic medium. A modified fiber according to the present invention that has not undergone acid hydrolysis is typically subjected to such a treatment by acid hydrolysis during the manufacturing process in order to produce cellulose ethers or esters.

As described above, fibers of the second and third types are made in processes in which derivatives are formed, or the fibers are hydrolyzed. These fibers may also be suitable for use in the manufacture of absorbent articles, absorbent paper products and cellulose derivatives, including ethers and esters.

V. Hydrolyzed Acid / Alkaline Products

According to some embodiments of the present invention, there is provided a modified sulfate fiber that can be used as a substitute for cotton fluff or sulfite pulp. According to some embodiments of the present invention, there is provided a modified sulfate fiber that can be used as a substitute for cotton fluff or sulfite pulp, for example, when cellulose ethers, cellulose acetates and microcrystalline cellulose are produced.

Not intending to be limited by theory, the authors believe that an increase in the content of aldehyde groups compared to traditional sulfate cellulose provides additional active centers for the esterification and production of end products, such as carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, etc., which ensures the production of fiber that can use to produce both paper and cellulose derivatives.

In some embodiments, the modified sulfate fiber has chemical properties that make it suitable to make cellulose ethers. Thus, the present invention provides cellulose ethers made from modified sulfate fiber as described above. In some embodiments, ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose and hydroxyethyl methyl cellulose are selected as cellulose ethers. The authors believe that the cellulose ethers according to the present invention can be used in any applications that traditionally use cellulose ethers. By way of example, but not limitation, the cellulose ethers of the present invention can be used to make coatings, paints, binders, controlled release tablets and films.

In some embodiments, the modified sulfate fiber has chemical properties that make it suitable to make cellulose esters. Thus, the present invention provides cellulose esters, such as cellulose acetate, derived from the modified sulfate fibers of the present invention. According to some embodiments of the present invention, there is provided an article comprising cellulose acetate, the source of which is a modified sulfate fiber according to the present invention. By way of example, but not limitation, the cellulose esters of the present invention can be used to make home furnishings, cigarettes, paints, absorbent articles, medical devices, and plastic products, including, for example, liquid crystal and plasma screens and windscreens.

In some embodiments, the modified sulfate fiber has chemical properties that make it suitable for the manufacture of microcrystalline cellulose. The manufacture of microcrystalline cellulose requires a relatively clean, highly purified cellulosic starting material. Thus, expensive sulfite cellulose is traditionally and mainly used for its manufacture. According to the present invention, there is provided microcrystalline cellulose, the source of which is a modified sulfate fiber according to the present invention. Thus, according to the present invention, an economical source of cellulose for producing microcrystalline cellulose is provided. According to some embodiments, the source of microcrystalline cellulose is a modified sulfate fiber having a polymerization degree that is less than about 100, for example, less than about 75 or less than about 50. According to some embodiments, the source of microcrystalline cellulose is a modified sulfate fiber having an R10 value of from about 65% to about 85%, for example, from about 70% to about about 85% or from about 75% to about 85%, and an R18 value of from about 75% to about 90%, for example, from about 80% to about 90%, for example, from about 80% to about 87%.

The modified cellulose according to the present invention can be used in any application in which microcrystalline cellulose is conventionally used. By way of example, but not limitation, the modified cellulose of the present invention can be used to make pharmaceutical or nutraceutical products, food products, cosmetics, paper products, or structural composite materials. For example, the modified cellulose according to the present invention may be a binder, diluent, disintegrant, lubricant, tablet preparation, stabilizer, texturing agent, fat replacer, sintering agent, foaming agent, emulsifier, thickener, release agent, gelling agent , a carrier material, an opacifier, or a viscosity modifier. In some embodiments, microcrystalline cellulose is a colloid.

VI. Products Containing Acid Hydrolyzed Products

According to some embodiments of the present invention, there is provided a pharmaceutical product comprising microcrystalline cellulose which is prepared using the modified hydrophilic sulfate fiber of the present invention. The pharmaceutical product may be any pharmaceutical product that traditionally uses microcrystalline cellulose. By way of example, but not limitation, the pharmaceutical product can be selected from tablets and capsules. For example, the microcrystalline cellulose according to the present invention may be a diluent, disintegrant, binder, compression aid, coating, and / or lubricant. According to other embodiments of the present invention, there is provided a pharmaceutical product comprising at least one modified and derivatized sulfate fiber according to the present invention, such as a hydrolyzed modified sulfate fiber.

According to some embodiments of the present invention, there is provided a food product comprising a bleached sulfate fiber of the present invention that has been hydrolyzed. According to some embodiments of the present invention, there is provided a food product comprising at least one product, the source of which is the bleached sulfate fiber of the present invention. According to further embodiments of the present invention, there is provided a food product comprising microcrystalline cellulose, the source of which is the sulfate fibers of the present invention. In some embodiments, the food product contains colloidal microcrystalline cellulose, the source of which is the sulfate fibers of the present invention. The food product can be any food product that has traditionally used microcrystalline cellulose. Exemplary categories of food products in which microcrystalline cellulose can be used are well known to those of ordinary skill in the art and are described, for example, by the Food Code, for example, in Table 3. For example, microcrystalline cellulose, the source of which is chemically modified sulfate fibers according to the present invention may be a sintering agent, filler, emulsifier, foaming agent, stabilizer, thickener, gelling agent and / or suspending agent.

Other products containing cellulose derivatives and microcrystalline cellulose, the source of which are the chemically modified sulfate fibers of the present invention, can also be developed by those of ordinary skill in the art. Such products may be present, for example, in cosmetic and industrial applications.

As used herein, the term “approximately” takes into account changes due to experimental error. All measurement results should be understood as modified by the word “approximately”, regardless of whether the word “approximately” is present, unless another condition is specified. Thus, for example, the expression “fiber having a length of 2 mm” should be understood as meaning “fiber having a length of approximately 2 mm”.

A detailed description of one or more non-limiting embodiments of the present invention is presented in the examples below. Other embodiments of the present invention should be apparent to those of ordinary skill in the art upon review of the present invention.

EXAMPLES

A. Research Protocols

1. Alkali solubility (R10, S10, R18, S18) is measured according to the TAPPI T235-cm00 procedure.

2. The content of carboxyl groups is measured according to the TAPPI T237-cm98 procedure.

3. Aldehyde groups are measured according to Econotech Services Ltd, proprietary ESM 055B procedure.

4. The copper number is measured according to the TAPPI T430-cm99 procedure.

5. The content of carbonyl groups is calculated based on the copper number according to the formula:

The content of carbonyl groups = (copper number - 0.07) / 0.6

(see Biomacromolecules, 2002, vol. 3, pp. 969-975).

6. The viscosity of a 0.5% solution is measured by the capillary method using CED according to the TAPPI T230-om99 procedure.

7. The intrinsic viscosity is measured according to ASTMD1795 (2007).

8. The degree of polymerization is calculated based on the viscosity of a 0.5% solution, measured by the capillary method using CED according to the formula:

Mass-average degree of polymerization = -449.6 + 598.4⋅ln (viscosity of 0.5% solution) + 118.02⋅ln ² (viscosity of 0.5% solution)

(see Cellucon Conference on the Chemistry and Processing of Wood and Plant Fiber Materials, 1994, Study Protocol 8, p. 155, edited by JF Kennedy et al., Woodhead Publishing Ltd., Abington Hall, Abinton, Cambridge, CBI 6AH, England).

9. The carbohydrate content is measured according to the TAPPI T249-cm00 procedure by analysis by ion chromatography on a Dionex system.

10. The cellulose content is calculated based on the carbohydrate composition according to the formula:

Cellulose content = glucan - (mannan / 3),

(see TAPPI Journal, 1982, vol. 65, No. 12, pp. 78-80).

11. The hemicellulose content is calculated by the sum of sugars minus the cellulose content.

12. Fiber length and fiber roughness are determined using a Fiber Quality Analyzer ™ from OPTEST (Hawkesbury, Ontario, Canada) according to standard manufacturer procedures.

13. The breaking length in the wet state at zero distance between the clamps is determined according to the TAPPI T273-pm99 procedure.

14. The degree of grinding is determined according to the TAPPI T227-om99 procedure.

15. The value of water retention capacity is determined according to the TAPPI UM 256 procedure.

16. The content of substances extracted with dichloromethane (DCM) is determined according to the TAPPI T204-cm97 procedure.

17. Iron content is determined by dissolving in acid and inductively coupled plasma (ICP) analysis.

18. Ash content is determined according to the TAPPI T211-om02 procedure.

19. The residual content of peroxides is determined according to the Interox procedure.

20. Whiteness is determined according to the TAPPI T525-om02 procedure.

21. Porosity is determined according to the TAPPI 460-om02 procedure.

22. The burst resistance index is determined according to the TAPPI T403-om02 procedure.

23. The tear resistance index is determined according to the TAPPI T414-om98 procedure.

24. The breaking length and deformation are determined according to the TAPPI procedure T494-om01.

25. Opacity is determined according to the TAPPI T425-om01 procedure.

26. Frazier porosity is determined using a low breathability Frazier instrument from Frazier Instruments (Hagerstown, Maryland, USA) according to the manufacturer's procedures.

27. The length and shape of the fiber is determined by the device for measuring the length and width of the fibers from Lorentzen & Wettre (Chist, Sweden) according to the standard procedures of the manufacturer.

28. The dirt content and bonfires are determined according to the TAPPI T213-om01 procedure.

B. An exemplary method of manufacturing a modified cellulose fiber

Semi-bleached or fully bleached sulfate cellulose can be treated with acid and hydrogen peroxide in the presence of iron to reduce the viscosity or degree of polymerization of the fiber. The pH of the fiber can be set in the range from about 2 to about 5 (if it is not already in this range), for which sulfuric, hydrochloric, acetic acid or filtrate from the washer are used in the acid bleaching stage, for which is used, for example, chlorine dioxide. Iron can be added in the form of Fe (II), for example, iron can be added in the form of iron (II) sulfate heptahydrate (FeSO ₄ ⋅ 7H ₂ O). Iron (II) sulfate can be dissolved in water at a concentration of from about 0.1 to about 48.5 g / L. A solution of iron (II) sulfate can be added in a ratio of from about 25 to about 200 parts per million Fe (II) in relation to the dry weight of cellulose. The iron (II) sulfate solution can then be thoroughly mixed with a predetermined pH cellulose at a consistency of from about 1% to about 15% when measured based on the dry cellulose content relative to the total wet weight of the cellulose. Hydrogen peroxide (H ₂ O ₂ ) can then be added in an aqueous solution, the concentration of which is from about 1% to about 50 wt.% H ₂ O ₂ , in an amount of from about 0.1% to about 3% with respect to dry pulp. Cellulose, the pH of which is from about 2 to about 5, is mixed with iron (II) sulfate, and the peroxide can react for a time of from about 40 to about 80 minutes at a temperature of from about 60 to about 80 ° C. The reduction in viscosity (or degree of polymerization) depends on the amount of peroxide used in the reaction, which determines the concentration and amount of peroxide and iron used, as well as the aging time and temperature.

The treatment can be carried out in a typical five-stage bleaching plant according to the standard sequence Do E1 D1 E2 D2. When using this scheme, no additional tanks, pumps, mixers, columns or washers are required. For processing, a fourth step or step E2 may preferably be used. The pH of the fiber in the scrubber in step D1 can be set in the range of from about 2 to about 5, adding acid or filtrate from step D2 as necessary. The iron (II) sulfate solution can be added to the cellulose by (1) spraying onto the washer substrate in step D1 and using existing spray heads or new heads, (2) adding via a spray mechanism through the spray, or (3) adding to the injection point in front of the mixer or a pump for the fourth stage. The peroxide in the form of a solution can be added after iron (II) sulfate to the point of introduction into the mixer or pump in front of the fourth stage column. Steam can also be introduced as necessary in front of the column into the steam mixer. Cellulose can then react in a column for an appropriate holding period. Chemically modified cellulose can then be washed in a fourth stage washer in normal operation. Additional bleaching can optionally be carried out after treatment in the fifth stage or stage D2, working in normal mode.

Example 1

Methods of making fibers according to the present invention

A. Method for treating cellulose A

Cellulose from southern pine wood was cooked and oxygen delignified in a traditional two-stage oxygen delignification unit to a permanganate number of about 9 to about 10. The delignified cellulose was bleached in a five-stage bleaching unit using the sequence D ₀ (EO) D1E2D2. Before the fourth step or step E2, the pH of the cellulose was adjusted to a range of from about 2 to about 5 using the filtrate from step D of this sequence. After the pH was established, 0.2% hydrogen peroxide was added with respect to the dry weight of cellulose and 25 ppm Fe (II) in the form _of FeSO ₄ ⋅ 7H ₂ O relative to the dry weight of cellulose in the sulfate fibers in the column in step E2, and the reaction continued for approximately 90 minutes at a temperature of from about 78 to about 82 ° C. The reacted fiber was then washed in a washer in a fourth step, and then bleached with chlorine in a fifth step (D2).

B. Method for treating cellulose B

The fiber was made according to the description of the processing method for cellulose A, except that this cellulose was treated using 0.6% peroxide and 75 ppm Fe (II).

C. Method for treating cellulose C

The fiber was made according to the description of the processing method for cellulose A, except that this cellulose was treated using 1.4% peroxide and 100 ppm Fe (II).

Properties of Exemplary Fibers

Fiber samples made according to the processing method of cellulose A (sample 2), B (sample 3) and C (sample 4) were obtained as a result of the implementation of the above five-stage bleaching sequence. Some of the properties of these samples, including standard fluff fiber (GP fiber sample 1 from Leaf River Cellulose (New August, Mississippi, USA)) and commercially available fiber (PEACH ™ fiber sample 5 sold by Weyerhaeuser Co.), measured according to the protocols described above. The results of these measurements are presented below in table 1.

Table 1 Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Fiber measurement Leaf River GP Fluff Pulp Cellulose The method of processing cellulose A The method of processing pulp B The method of processing cellulose C PEACH fiber from Weyerhaeu-ser Co. R10 % 86.8 85,2 82,4 72.5 78,4 S10 % 13,2 14.8 17.6 27.5 21.6 R18 % 87.0 87.2 85,4 78.7 84,4 S18 % 13.0 12.8 14.6 21.3 15.6 ΔR 0.2 0.2 3.0 6.2 6.0 The content of carboxyl groups meq / 100 g 3.13 3.53 3.70 3.94 3.74 The content of aldehyde groups meq / 100 g 0.97 1.24 2.15 4.21 0.87 Copper number 0.51 1,2 1.3 4.25 1.9 The calculated content of carbonyl groups mmol / 100 g 0.73 1.88 2.05 6.97 3.05 The calculated ratio of the content of carbonyl groups and aldehyde groups 0.75 1,52 0.95 1,66 3,5 Capillary viscosity using a CED viscosity of 0.5% solution mPa⋅s 15.0 8.9 6.5 3,50 4.16 Intrinsic viscosity [η] dl / g 7.14 5.44 4.33 2.49 3.00 The calculated degree of polymerization DPw 2036 1423 1084 485 643 Glucan % 83.0 85.9 84.9 85,4 82 Xylan % 9.0 8.8 9,4 8.2 8.4 Galactan % 0.2 0.2 0.2 0.2 0.2 Mannan % 5.9 5,4 5.3 5.5 6.2 Arabinan % 0.4 0.3 0.3 0.4 0.3 The calculated cellulose content % 81.0 84.1 82.8 83.6 79.9 The calculated hemicellulose content % 17.5 16.5 17.0 16.1 17,2 Fiber Length Lwl mm 2,34 2,57 2,53 2,30 2.19 Fiber Length Lww mm 3.39 3.34 3.34 3.01 Roughness 0.222 0.234 0.19 0.254 Bursting length when wet with zero distance between clamps Km 9.38 6.83 5.01 2,3 Content of dichloromethane extractable substances 0.006 0.006 Iron content parts per million 5.5 4.4 Water Retention Capacity (WRV) 0.98 0.99 0.85 White % ISO 89.6 89.0 88.2 88.5 88.5

As shown in table 1, the iron content in the control fiber (sample 1) was not measured. However, the iron content in the cellulose samples prepared at four plants was measured under the same conditions as those described for sample 1. The iron content in these samples averaged 2.6 ppm. Accordingly, for sample 1, it can be assumed that the iron content is approximately 2.5 ppm.

As can be seen in Table 1, the modified fiber according to the present invention unexpectedly differs from the control fiber (sample 1) and the alternative commercially available oxidized fiber (sample 5) with respect to the total content of carbonyl groups, as well as the content of carboxyl groups and the content of aldehyde groups. Since there is a difference between the total content of carbonyl groups and aldehyde groups, additional carbonyl functional groups may be present in another form of ketone groups. These data show that relatively high levels of aldehyde groups are achieved, while the content of carboxyl groups is maintained, and a ratio of the content of aldehyde groups and total carbonyl groups is close to unity (as can be seen in table 1, it is approximately 1.0 ( 0.95) to 1.6). This is even more unexpected in the case of a fiber that exhibits high whiteness, as well as a relatively high strength and absorbency.

As can be seen in table 1, the standard fluff fiber (sample 1) had a carboxyl group content of 3.13 meq / 100 g and an aldehyde group content of 0.97 meq / 100 g. After treatment with a low dose of 0.2% H ₂ O ₂ in the presence of 25 ppm Fe (II) (sample 2) or after treatment with a high dose of 0.6% H ₂ O ₂ in the presence of 75 ppm Fe (II) (sample 3), or after processing more a high dose of 1.4% H ₂ O ₂ in the presence of 100 ppm Fe (II) (sample 4) the fiber length and the calculated cellulose content remained relatively unchanged and the fiber strength, measured in the wet state at zero distance between the clamps, decreased to some extent, and the content of carboxyl, carbonyl and aldehyde groups increased, indicating a significant oxidation of cellulose.

By way of comparison, a commercially available sample of oxidized sulphate coniferous fiber from southern pine wood made by an alternative method (sample 5) represents a significant reduction in fiber length and approximately 70% reduction in fiber strength, measured in the wet state at zero distance between the clamps, compared with fluffy fiber described as sample 1. The content of aldehyde groups in sample 5 remained virtually unchanged compared to standard fluffy fiber, while fibers according to the present invention are manufactured by processing methods A-C (samples 2-4) had a somewhat higher content of aldehyde groups of from about 70 to about 100% of the calculated total content of carbonyl groups in the cellulose. On the other hand, the content of aldehyde groups in the PEACH® fiber was less than 30% of the total calculated content of carbonyl groups in the cellulose. The ratio of the total content of carbonyl groups and the content of aldehyde groups, apparently, is a good indicator that the fiber can have wide applicability as a modified fiber within the scope of the present invention, in particular, if this ratio is in the range from about 1 to about 2, as in samples 2-4. Having low viscosity fibers, such as samples 3 and 4, in which the ratio of the content of carbonyl and aldehyde groups ranged from about 1.5 to less than 2.0, the fiber length was maintained, in contrast to comparative sample 5.

The degree of grinding, density and strength of the standard fiber described above (sample 1) were compared with the parameters of the sample described above 3. The results of this analysis are presented in table 2.

Table 2. Pulp, paper and fiber properties for standard and modified sulfate fibers RPM when cleaning with PFI The degree of grinding (CSF) Density, g / cm ³ Breaking length, km The breaking length in the wet state at zero distance between the clamps, km A standard fluffy Leaf River fiber with a viscosity of 0.5% solution, measured by capillary method using CED, is approximately 15 mPa⋅s (sample 1) 0 737 0.538 2.16 9.38 300 721 0.589 3.57 Modified cellulose fiber (ULDP), in which the viscosity of a 0.5% solution, measured by capillary method using CED, is 6.5 MPa · s (sample 3) 0 742 0.544 2.19 6.83 300 702 0.595 3.75

As can be seen in Table 2 above, the modified cellulosic fibers according to the present invention can have a degree of milling comparable to standard fluffy fibers that have not been oxidized in the bleaching sequence.

Example 2

A pulp sample of southern pine wood after stage D1 of the bleaching OD (EOP) D (EP) D sequence, in which the viscosity of a 0.5% solution, measured by capillary method using CED, was approximately 14.6 mPa · s, was processed at approximately 10 % consistency with hydrogen peroxide at a concentration of 0.25% to 1.5% in the presence of 50 or 100 ppm Fe (II) added in the form _of FeSO ₄ ⋅ 7H ₂ O. Fe (II) was added in the form of an aqueous solution and carefully mixed with cellulose. Then, hydrogen peroxide in the form of a 3% aqueous solution was mixed with cellulose. The mixed cellulose was aged in a water bath for one hour at 78 ° C. After completion of the reaction, the cellulose was filtered, and the pH and residual peroxide content were measured in the filtrate. The cellulose was washed and the viscosity of the 0.5% solution measured by the capillary method using CED was determined according to the TAPPI T230 procedure. The results are presented in table 3.

Table 3 Added H ₂ O ₂ Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp final value mPa⋅s Control sample 14.6 2003 0.25 0.25 one hundred 4.8 8.6 6.0 1384 0.50 0.34 fifty 4.7 8.9 5.7 1423 0.50 0.50 one hundred 4.8 6.8 7.8 1131 0.75 0.19 fifty 4.6 10.6 4.0 1621 0.75 0.75 one hundred 4.7 5.8 8.8 967 1,0 0.20 fifty 4.6 9.0 5,6 1435 1,0 0.40 one hundred 4.7 7.8 6.8 1278 1,5 0.30 fifty 4.6 10.0 4.6 1554 1,5 0.40 one hundred 4.6 7.5 7.1 1235

Example 3

The cellulose sample after the bleaching stage D1 in the apparatus described in Example 2, in which the viscosity of a 0.5% solution measured by the capillary method using CED was 15.8 mPa · s (DPw 2101), was treated with a solution of 0.75% hydrogen peroxide in the presence of Fe (II) in an amount of 50 to 200 ppm, in the same manner as in Example 2, except that the aging time also varied from 45 to 80 minutes. The results are presented in table 4.

Table 4 Processing time Added H ₂ O ₂ Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw minutes % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp final value mPa⋅s 2101 Control sample 15.8 1291 45 0.75 0.72 one hundred 4.4 7.9 7.9 1035 60 0.75 0.75 200 4.1 6.2 9.6 1384 80 0.75 0.27 fifty 8.6 7.2 1018 80 0.75 0.75 one hundred 4.6 6.1 9.7 2101

Example 4

The cellulose sample after the bleaching stage D1 in the apparatus described in Example 2, in which the viscosity of a 0.5% solution measured by the capillary method using CED was 14.8 mPa · s (DPw 2020), was treated with a solution of 0.75% hydrogen peroxide in the presence of 150 ppm Fe (II) in the same manner as described in example 2, except that the processing time was 80 minutes. The results are presented in table 5.

Table 5 Processing time Added H ₂ O ₂ Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw minutes % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp final value mPa⋅s Control sample 14.8 2020 80 0.75 0.75 150 3.9 5.2 9.6 858

Example 5

Cellulose from southern pine wood after stage D1 of the sequence OD ₀ (EO) D1 (EP) D2, in which the viscosity of a 0.5% solution measured by the capillary method using CED was 15.6 mPa⋅s (DPw 2085), was treated at 10% consistency with a solution of hydrogen peroxide of 0.25% or 0.5 wt.% with respect to cellulose, in the presence of 25, 50, or 100 ppm Fe (II) added in the form _of FeSO ₄ ⋅ 7H ₂ O. Fe ( Ii) was added in the form of an aqueous solution and thoroughly mixed with cellulose. Hydrogen peroxide in the form of a 3% aqueous solution was then mixed with cellulose, and the mixed cellulose was kept in a water bath for one hour at 78 ° C. After completion of the reaction, the cellulose was filtered, and the pH and residual peroxide were measured at the filtrate. Cellulose was washed and the viscosity of a 0.5% solution measured by the capillary method using CED was determined according to the TAPPI T230 procedure. The results are presented in table 6.

Table 6 Added H ₂ O ₂ Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp final value mPa⋅s Control sample 15.6 2085 0.25 0.25 25 3,5 6.4 9.2 1068 0.50 O 50 fifty 2.9 4,5 11.1 717 0.50 0.50 one hundred 2.7 4,5 11.1 717

Example 6

The next cellulose sample after stage D1, in which the viscosity of a 0.5% solution measured by the capillary method using CED was 15.2 mPa · s (DPw 2053), was treated with a solution of 0.10, 0.25, 0.50, or 0, 65% hydrogen peroxide in the presence of 25, 50, or 75 parts per million Fe (II) in the same manner as in example 5. The results are presented in table 7.

Table 7 Processing time Added H ₂ O ₂ Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw minutes % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp final value mPa⋅s Control sample 15,2 2053 60 0.10 0.10 25 4.1 9.6 5,6 1508 60 0.25 0.19 25 4.0 7.9 7.3 1291 60 0.50 0.40 fifty 3,5 6.7 8.5 1116 60 0.65 0.65 75 3.3 4.4 10.8 696

Example 7

Cellulose from southern pine wood was obtained in stage D1 of the bleaching sequence OD (EO) D (EP) D after the oxygen delignification stage of sulfate cellulose, resulting in cellulose having a lower weight average polymerization degree or measured by a capillary method using a CED viscosity of 0.5% solution. The initial viscosity measured by a capillary method using CED of a 0.5% solution was 12.7 mPa · s (DPw 1834). A solution of 0.50 or 1.0% hydrogen peroxide was added in the presence of 100 ppm Fe (II). Other processing conditions were 10% consistency, 78 ° C and one hour treatment time. The results are presented in table 8.

Table 8 Added H ₂ O ₂ Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp final value mPa⋅s Control sample 12.7 1834 0.50 0.50 one hundred 2.1 5,6 7.1 932 1,0 0.35 one hundred 2.6 4.2 8.5 652

Example 8

The low viscosity cellulose sample after stage D1 of the OD (EO) D (EP) D sequence, in which the viscosity of the 0.5% solution measured by the capillary method using CED was 11.5 mPa · s (DPw 1716), was treated with a solution of 0.75 or 1.0% hydrogen peroxide in the presence of 75 or 150 parts per million Fe (II) in a manner analogous to example 7, except that the processing time was 80 minutes. The results are presented in table 9.

Table 9 Added H ₂ O ₂ Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp final value mPa⋅s Control sample 11.5 1716 0.75 0.75 75 3.2 3.6 7.9 511 0.75 0.75 150 3.0 3.8 7.7 560 one one 75 2.6 3.4 8.1 459 one one 150 2.6 3.4 8.1 459

Example 9

Cellulose from southern pine wood was obtained in step D1 of the sequence OD (EO) D (EP) D. The initial viscosity measured by a capillary method using CED of a 0.5% solution was 11.6 mPa · s (DPw 1726). A solution of 1.0%, 1.5%, or 2% hydrogen peroxide was added in the presence of 75, 150, or 200 ppm Fe (II). Other processing conditions were 10% consistency, 78 ° C and an hour and a half treatment time. The results are presented in table 10.

Table 10 Added H ₂ O Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw The content of carboxyl groups The content of aldehyde groups Copper number % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp final value mPa⋅s meq / 100 g meq / 100 g Control sample 11.6 1726 3.67 0.35 0.52 1,0 0.98 75 3.4 3,5 8.1 485 3.73 4.06 3.05 1,5 1.49 150 2.7 3.2 8.4 406 3.78 5.06 2,57 2.0 2.0 200 2.9 3.0 8.6 350 3.67 5.23 2.06

Example 10

Cellulose from southern pine wood was obtained in step D1 of the sequence OD (EO) D (EP) D. The initial viscosity measured by a capillary method using CED of a 0.5% solution was 14.4 mPa · s (DPw 1986). A solution of 1.0%, 1.5%, or 2% hydrogen peroxide was added in the presence of 75, 150, or 200 ppm Fe (II). Other processing conditions were 10% consistency, 78 ° C and an hour and a half treatment time. The results are presented in table 11.

Table 11 Added H ₂ O Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw The content of carboxyl groups The content of aldehyde groups Copper number % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp Final value mPa⋅s meq / 100 g meq / 100 g Control sample 14,4 1986 3.52 0.23 0.67 1,0 0.95 75 3.3 3.8 10.6 560 3.65 3.48 2.47 1,5 1,5 150 2,4 3,7 10.7 535 4.13 4.70 2,32 2.0 2.0 200 2,8 3.2 11,2 406 3.93 5.91 1.88

Example 11

Cellulose from southern pine wood was obtained in step D1 of the sequence OD (EO) D (EP) D. The initial viscosity measured by the capillary method using CED of a 0.5% solution was 15.3 mPa · s (DPw 2061). Hydrogen peroxide was added to cellulose in a 3% solution in the presence of 200 ppm Fe (II). Other processing conditions were 10% consistency, 80 ° C and an hour and a half treatment time. The results are presented in table 12.

Table 12 Added H ₂ O Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw The content of carboxyl groups The content of aldehyde groups Copper number % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp Final value mPa⋅s meq / 100 g meq / 100 g Control sample 15.3 2061 3.0 2.9 200 2,8 2.94 12,4 333 4.66 6.74 5.14

The above examples 2-11 show that a significant reduction in the capillary method measured using the CED viscosity of a 0.5% solution and / or degree of polymerization can be achieved by acid catalyzed peroxide treatment according to the present invention. The final viscosity or weight average polymerization degree is dependent on the amount of peroxide that is consumed during the reaction, as shown in FIG. 1, which illustrates the viscosity of cellulose from two different plants, namely Brunswick and Leaf River (LR), as a function of the percentage of peroxide consumed. Peroxide consumption determines the amount and concentration of peroxide used, processing time and reaction temperature.

Example 12

Cellulose from southern pine wood was obtained in step D1 of the sequence OD (EO) D (EP) D. The initial viscosity measured by a capillary method using CED of a 0.5% solution was 14.8 mPa · s (DPw 2020). Hydrogen peroxide was added in a solution of 1% cellulose in the presence of 100, 150, or 200 ppm Cu (II) added in the form of CuSO ₄ ⋅ 5H ₂ Oe. Other processing conditions were 10% consistency, 80 ° C, and a 3.5 hour treatment time. The results are presented in table 13.

Table 13 Added H ₂ O Spent H ₂ O ₂ Fe ⁺² pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw The content of carboxyl groups The content of aldehyde groups Copper number % in relation to the mass of cellulose % in relation to the mass of cellulose parts per million in relation to the mass of pulp final value mPa⋅s meq / 100 g meq / 100 g Control sample 14.8 2020 3.36 0.37 0.51 1,0 0.82 one hundred 2,4 6.1 8.7 1018 1,0 0.94 150 2,3 5.9 8.9 984 1,0 0.94 200 2,4 6.0 8.8 1001 3.37 2.71 1.8

The use of copper instead of iron led to a slowdown of the reaction and a decrease in viscosity, but nevertheless a significant change was observed in the viscosity, the content of carboxyl groups and the content of aldehyde groups in comparison with the control sample of untreated cellulose.

Example 13

Stage E2 (EP) of the sequence OD (EOP) D (EP) D was changed to obtain an ultra-low degree of polymerization of cellulose. A solution _of FeSO ₄ ⋅ 7H ₂ O was sprayed onto cellulose using a spray washer in step D1 when applied in an amount of 150 ppm Fe (II). No alkali (NaOH) was added in step E2, and the peroxide content increased to 0.75%. The aging time was approximately 1 hour, and the temperature was 79 ° C. The pH value was 2.9. The treated cellulose was washed using a vacuum drum washer, and then treated at the final stage D2 using 0.7% ClO ₂ for about 2 hours at 91 ° C. Measured by capillary method using CED, the viscosity of a 0.5% solution of the final bleached pulp was 6.5 MPa · s (DPw 1084), and the whiteness was 87 according to ISO standard.

Example 14

From the pulp made in Example 13, it was prepared into laminated board using a Fourdrinier type drying apparatus and standard drying tanks. Cellulose control samples and cellulose samples according to the present invention (ULDP) were collected and analyzed in relation to the chemical composition and properties of the fibers. The results are presented in table 14.

Table 14 Property Standard ULDP R10 % 85,2 81.5 S10 % 14.8 18.5 R18 % 86.4 84,4 S18 % 13.6 15.6 ΔR 1,2 2.9 The content of carboxyl groups meq / 100 g 4.06 4.27 The content of aldehyde groups meq / 100 g 0.43 1.34 Copper number 0.32 1,57 The calculated content of carbonyl groups mmol / 100 g 0.42 2,50 Capillary viscosity using a CED viscosity of 0.5% solution mPa⋅s 14.2 7.3 Intrinsic viscosity dl / g 6.76 4.37 The calculated degree of polymerization DPw 1969 1206 Glucan % 83.6 83.6 Xylan % 9.2 9.0 Galactan % 0.2 0.2 Mannan % 6.3 6.4 Arabinan % 0.4 0.4 The calculated cellulose content % 81.5 81.5 The calculated hemicellulose content % 18.2 18.1 Fiber Length Lwl mm 2,51 2,53 Fiber Length Lww mm 3.28 3.26 Roughness mg / m 0.218 0.213 Bursting length when wet with zero distance between clamps Km 9.86 6.99 The degree of grinding (CSF) ml 720 742 Water retention ability g H ₂ O / g cellulose 0.96 0.84 Content of dichloromethane extractable substances 0.008 0.007 Iron content parts per million 3,5 10.7 Ash content % 0.20 0.22 White % ISO 90,4 86.5

Treated cellulose (ULDP) had a higher solubility in alkali (solutions of 10% and 18% NaOH), as well as a higher content of aldehyde groups and a total content of carbonyl groups. Cellulose ULDP had a significantly lower degree of polymerization, determined on the basis of the measured capillary method using the CED viscosity of a 0.5% solution. The decrease in fiber integrity was also determined by the decrease in tensile strength in the wet state at zero distance between the clamps. Despite a significant decrease in the degree of polymerization, the fiber length and degree of grinding remained almost unchanged. There was no adverse effect on the stock or production of cardboard on the machine.

Example 15

Stage E2 (EP) of the sequence OD (EO) D (EP) D was changed to produce ultra-low polymerization cellulose in a similar manner to Example 13. In this example, FeSO ₄ ⋅ 7H ₂ O was added in an amount of 75 ppm as Fe ( II), and the amount of hydrogen peroxide used in step E2 was 0.6%. The pH at the treatment stage was 3.0, the temperature was 82 ° C, and the aging time was approximately 80 minutes. Cellulose was washed and then treated in step D2 using 0.2% ClO ₂ at 92 ° C for approximately 150 minutes. Measured by capillary method using CED, the viscosity of a 0.5% solution of fully bleached pulp was 5.5 MPa · s (DPw 914), and the whiteness was 88.2 according to ISO standard.

Example 16

Laminated board was prepared from the pulp manufactured in Example 15 using a Fudrinier type drying apparatus with a Flakt ™ air drying section. Standard pulp samples and pulp samples according to the present invention (ULDP) were collected and analyzed in relation to the chemical composition and properties of the fibers. The results are presented in table 15.

Table 15 Property Standard ULDP R10 % 86.8 82,4 S10 % 13,2 17.6 R18 % 87.0 85,4 S18 % 13.0 14.6 ΔR 0.2 3.0 The content of carboxyl groups meq / 100 g 3.13 3.70 The content of aldehyde groups meq / 100 g 0.97 2.15 Copper number 0.51 1.3 The calculated content of carbonyl groups mmol / 100 g 0.73 2.05 Capillary viscosity using a CED viscosity of 0.5% solution mPa⋅s 15.0 6.5 Intrinsic viscosity dl / g 7.14 4.33 The calculated degree of polymerization DPw 2036 1084 Glucan % 83.0 84.6 Xylan % 9.0 9,4 Galactan % 0.2 0.2 Mannan % 5.9 5.3 Arabinan % 0.4 0.3 The calculated cellulose content % 81.0 82.8 The calculated hemicellulose content % 17.5 17.0 Fiber Length Lwl mm 2,55 2,53 Fiber Length Lww mm 3.29 3.34 Roughness mg / m 0.218 0.234 Bursting length when wet with zero distance between clamps Km 9.38 6.83 The degree of grinding (CSF) ml 738 737 Iron content parts per million 1,6 4.4 White % ISO 89.6 88.2

Treated cellulose (ULDP) had a higher solubility in alkali (solutions of 10% and 18% NaOH), as well as a higher content of aldehyde groups and a total content of carbonyl groups. Cellulose ULDP had a significantly lower degree of polymerization, determined on the basis of the measured capillary method using a CED viscosity of 0.5% solution and a smaller breaking length in the wet state at zero distance between the clamps. Whiteness still retained an acceptable value of 88.2. During processing, the fiber length and degree of grinding were preserved, and there were no any technological problems in the manufacture and drying of cardboard.

Example 17

Stage E2 (EP) of the sequence OD (EO) D (EP) D was altered to produce cellulose having a low degree of polymerization in a manner analogous to Example 13. In this case, FeSO ₄ ⋅ 7H ₂ O was added in an amount of 25 ppm as Fe ( II), and the amount of hydrogen peroxide used in step E2 was 0.2%. The pH at the treatment stage was 3.0, the temperature was 82 ° C, and the aging time was approximately 80 minutes. Cellulose was washed and then treated in step D2 using 0.2% ClO ₂ at 92 ° C for approximately 150 minutes. Measured by capillary method using CED, the viscosity of a 0.5% solution of fully bleached pulp was 8.9 mPa⋅s (DPw 1423), and the whiteness was 89 according to ISO standard.

Example 18

From the cellulose manufactured in Example 15, it was prepared into laminated paperboard using a Foudrinier type drying apparatus with a Flakt ™ air drying section. Standard pulp samples and cellulose samples according to the present invention (LDP) were collected and analyzed in relation to the chemical composition and properties of the fibers. The results are presented in table 16.

Table 16 Property Standard ULDP R10 % 86.8 85,2 S10 % 13,2 14.8 R18 % 87.0 87.2 S18 % 13.0 12.8 ΔR 0.2 2.0 The content of carboxyl groups meq / 100 g 3.13 3.53 The content of aldehyde groups meq / 100 g 0.97 1.24 Copper number 0.51 1,2 The calculated content of carbonyl groups mmol / 100 g 0.73 1.88 Capillary viscosity using a CED viscosity of 0.5% solution mPa⋅s 15.0 8.9 Intrinsic viscosity dl / g 7.14 5.44 The calculated degree of polymerization DPw 2036 1423 Glucan % 83.0 85.9 Xylan % 9.0 8.8 Galactan % 0.2 0.2 Mannan % 5.9 5,4 Arabinan % 0.4 0.3 The calculated cellulose content % 81.0 84.1 The calculated hemicellulose content % 17.5 16.5 Fiber Length Lwl mm 2,55 2,57 Fiber Length Lww mm 3.29 3.34 Roughness mg / m 0.218 0.222 Iron content parts per million 1,6 5.5 White % ISO 89.6 89.0

Treated cellulose (LDP) had a higher solubility in alkali (solutions of 10% and 18% NaOH), as well as a higher content of aldehyde groups and a total content of carbonyl groups. LDP cellulose had a lower degree of polymerization, determined on the basis of the capillary method measured using the CED viscosity of a 0.5% solution. There was minimal loss of whiteness. During processing, the fiber length was preserved, and there were no any technological problems in the manufacture and drying of cardboard.

Example 19

The cellulose sheets described in Example 14 were subjected to fluffing and pneumatic molding to obtain sheets measuring 4 x 7 inches (10.16 x 17.78 cm) using a Kamas laboratory hammer mill from Kamas Industries (Sweden). The sheets produced by pneumoforming were then compressed at various gauge pressures using a laboratory press. After pressing, the sheet thickness was measured using a Model 200-A micrometer thickness gauge from Emveco at a foot pressure of 0.089 psi (613.6 Pa). The density of the sheets was calculated by measuring the mass and thickness of the sheets. The results are presented in table 17.

Table 17 Gauge pressure 5 pounds per square
inch 10 pounds on
square inch 20 pounds on
square inch Thickness mm Sheet weight, g Density, g / cm ³ Thickness mm Sheet weight, g Density, g / cm ³ Thickness mm Sheet weight, g Density, g / cm ³ Standard Sulphate Fiber from Southern Pine Wood 2.62 5.14 0.108 2.29 5.27 0.127 1.49 5.29 0.196 2.81 5.14 0,101 2.26 5.19 0.127 1.42 5.23 0,203 Modified Sulphate Fiber from Southern Pine Wood 2,51 5.16 0.114 2.13 5.33 0.138 1.23 5.39 0.242 2,56 5.26 0.114 1.93 5.37 0.154 1.32 5.26 0.220 Percentage increase in density 8.43 14.94 15.67

The data in table 17 show that the modified fibers made within the scope of the present invention were more compressible, and as a result, they had a lower thickness and higher structure density, more suitable for modern designs of disposable absorbent articles.

Not intending to be limited by theory, the authors believe that the oxidation of cellulose disrupts the crystalline structure of the polymer, making it less rigid and more deformable. In this case, the fibers constituting the structure of the modified cellulose become more compressible, enabling the manufacture of higher density absorbent structures.

Example 20

Cellulose from southern pine wood was obtained in step D1 of the sequence OD (EO) D (EP) D. The initial viscosity measured by a capillary method using CED of a 0.5% solution was 14.9 mPa · s (DPw 2028). A solution of 1.0% or 2% hydrogen peroxide was added in the presence of 100 or 200 ppm Fe (II), respectively. Other processing conditions were 10% consistency, a temperature of 80 ° C, and a one-hour aging time. This fluffy cellulose was then suspended in deionized water, laid out wet on a mesh to form a fibrous sheet, dried using a roller press, and dried at 250 ° F (121.1 ° C). The dry sheets were subjected to fluffing and pneumatic molding to obtain sheets having dimensions of 4 × 7 inches (10.16 × 17.78 cm) and a mass of 8.4 g (after air drying) using a Kamas laboratory hammer mill from Kamas Industries ( Sweden). One fully covering sheet of nonwoven coating material was applied to one side of each cellulosic sheet, and the samples were densified using a hydraulic plate press from Carver, with a gauge pressure of 145 psi (0.9997 MPa).

These sheets were placed in 1.6 L individual airtight plastic containers having a removable lid equipped with a shut-off valve and a sampling hole with a Tygon® tube having an inner diameter of ¼ inch (6.35 mm). Before fixing the container lid as a load, 60 g of deionized water and 0.12 g of a solution of 50% NH ₄ OH at room temperature were poured into a centered vertical tube having an internal diameter of 1 inch (2.54 cm) on an input device capable of applying the entire sample has a pressure of 0.1 psi (689.5 Pa). After the load was completely absorbed, the input device was removed from the sample, the lid with the attached sampling hole was mounted on the container, and the countdown timer was started. After 45 minutes, an air sample above the solution was taken through a sampling hole to which an ammonia quick detection tube and ACCURO® bellows pump, supplied by Dräger Safety Inc., were connected. (Pittsburgh, PA, USA). The data in table 18 show that the modified fibers manufactured within the scope of the present invention were able to reduce the amount of gaseous ammonia in the space above the solution, and as a result, a structure is obtained that suppresses the release of volatile odor compounds that are often released from wetted products for incontinence sufferers.

Table 18 Load: 60 g of H ₂ O + 0.12 g of a solution of 50% NH ₄ OH Measured by capillary method using CED viscosity of 0.5% solution (mPa⋅s) The content of aldehyde groups (meq / 100 g) The weight of the laid sheet (g) Ammonia (ppm) after 45 minutes Standard Sulphate Fiber from Southern Pine Wood 14.9 0.23 9.16 210 Modified Sulphate Fiber from Southern Pine Wood - 1.0% H ₂ O ₂ + 100 ppm Fe 4.7 3.26 9.11 133 Modified Sulphate Fiber from Southern Pine Wood - 2.0% H ₂ O ₂ + 200 ppm Fe 3.8 4.32 9.23 107

Example 21

The E2 step of the OD (EO) D (EP) D sequence of the industrial sulphate pulp treatment process was changed to produce a low polymerization cellulose in a similar manner to Example 14. In this example, in step E2, 100 ppm FeSO ₄ ⋅ 7H ₂ O was added million as Fe (II), and hydrogen peroxide was added in an amount of 1.4%. pulp properties are presented in table 19.

Table 19 Property ULDP R10 % 72.5 S10 % 27.5 R18 % 78.7 S18 % 21.3 ΔR 6.2 The content of carboxyl groups meq / 100 g 3.94 The content of aldehyde groups meq / 100 g 4.21 Copper number 4.25 The calculated content of carbonyl groups mmol / 100 g 6.97 Capillary viscosity using a CED viscosity of 0.5% solution mPa⋅s 3,50 Intrinsic viscosity dl / g 2.49 The calculated degree of polymerization DPw 485 Fiber Length Lwl mm 2,31 Roughness mg / m 0.19 White % ISO 88.5

Laminated cardboard was made from the obtained modified chemical cellulose using a Foudrinier type drying apparatus with a Flakt ™ air drying section. Samples of this product and control samples of sulphate pulp sheets were subjected to fluffing using a Kamas laboratory hammer mill. Optical fiber properties were analyzed before and after processing the samples using a Kamas laboratory hammer mill using a HiRes fiber quality analyzer, supplied by Optest Equipment, Inc. (Hawkesbury, Ontario, Canada), according to manufacturer's protocols. The results are presented in the table below.

Table 20 Property Control sample ULDP Control sample after hammer mill ULDP sample after hammer mill Bend index 1.79 2.29 1.51 2,32 Bending angle 59.15 79.56 48.52 80.26 The number of bends per 1 mm 0.81 1,07 0.68 1.06 Curl Index (Weighted Length) 0.171 0.211 0.149 0.225

As can be seen in table 20, ULDP fibers made in accordance with the present invention have higher bending and crimping indices than control fibers not treated with peroxide in the presence of iron,

The fluffed fibers were subjected to pneumoforming, producing sheets having dimensions of 4 × 7 inches (10.16 × 17.78 cm) and a weight of 4.25 g (after drying in air). BASF's sodium polyacrylate superabsorbent (SAP) pellets were uniformly placed between two 4.25 g sheets. A fully coated nonwoven coating material was placed on the upper side of the fiber / SAP matrix and the sheet using a company hydraulic press plate Carver applying 145 psi (0.9997 MPa) gauge pressure.

Synthetic urine was prepared by dissolving 2% urea, 0.9% sodium chloride and 0.24% Criterion ™ branded nutrient broth from Hardy Diagnostics (Santa Maria, California, USA) in deionized water and adding an aliquot of Proteus Vulgaris bacteria , resulting in an initial concentration of bacteria of 1.4 × 10 ⁷ CFU / ml. The sheet described above was then placed in a chamber for studying the composition of the gas above the solution, as described in example 20, and 80 ml of synthetic urine solution was poured onto it. Immediately after this, the chamber was sealed and placed in an environment with a temperature of 30 ° C. Sampling using the Dräger system was carried out sequentially with time intervals of 4 hours and 7 hours. The experiment was repeated three times, and the average results are presented in table 21.

Table 21 SAP Additive (%) Ammonia content after 4 hours (ppm) The decrease compared with the control sample (%) Ammonia after 7 h (ppm) The decrease compared with the control sample (%) Modified Sulphate Fiber from Southern Pine Wood 23 2,5 29th Control sulphate fiber from southern pine wood 23 21.5 88 175 83 Modified Sulphate Fiber from Southern Pine Wood 16.5 6.5 123 Control sulphate fiber from southern pine wood 16.5 36.5 82 550 78 Modified Sulphate Fiber from Southern Pine Wood 0 70 317 Control sulphate fiber from southern pine wood 0 197.5 65 575 45

As can be seen from these data, the ammonia content of the atmosphere as a result of bacterial hydrolysis of urea is lower in the case of composite products (similar in design to commercially available products for urinary incontinence) containing modified cellulose fibers made within the scope of the present invention, compared to composite products containing standard sulphate fibers from southern pine wood. Thus, products containing the modified cellulose fibers of the present invention showed improved odor control properties than products containing standard sulphate fibers from southern pine wood.

Example 22. Comparison of the fourth stage of processing after bleaching

Cellulose from southern pine wood was obtained in step D1 of the sequence OD (EO) D1 (EP) D2. The initial viscosity measured by capillary method using CED of 0.5% solution was 14.1 mP⋅. Hydrogen peroxide was added in an amount of 1.5% based on the dry weight of cellulose and 150 ppm Fe (II). As used herein, the term “P *” is used to indicate the stage of treatment with hydrogen peroxide in the presence of iron. The treatment was carried out at a consistency of 10% and a temperature of 78 ° C for one hour in the fourth stage of the sequence. This treated cellulose was then washed and bleached in step D2 using 0.25% ClO ₂ . for two hours at 78 ° C. The results are presented in table 22.

Table 22 Stage Chemicals Added pH Capillary viscosity using a CED viscosity of 0.5% solution Viscosity change DPw White Length-weighted average fiber length % in relation to the mass of cellulose final value mPa⋅s % ISO mm D1 14.1 1960 83.5 P * 1.5% H ₂ O ₂ 150 ppm Fe ⁺² 3,1 82.0 D2 0.25% ClO ₂ 2.7 3,7 10,4 540 89.5 2.20

The sample previously obtained in step D2 was also examined for whiteness recovery, keeping it in an oven at 105 ° C for one hour. The brightness values, as well as the coordinates L * (whiteness), a * (scale of red and green colors), and b * (scale of blue and yellow colors) were measured using a MiniScan device from HunterLab, according to the manufacturer's protocols, before and after reconditioning . The results are presented in table 23 below. More positive values of b show a more yellow color. Thus, elevated b values are undesirable for most paper and pulp products. The color change after bleaching, which is shown below, is the difference in the k / s ratios before and after bleaching, where k is the absorption coefficient and s is the scattering coefficient, i.e., the color change after bleaching is = 100⋅ {(k / s) _{after bleaching} - (k / s) _{before bleaching} }. See, for example, article HW Giertz, Svensk Papperstid, 1945, v. 48, No. 13, p. 317.

Table 23. Whiteness restoration Stage L * a * b * White Δ Change in whiteness Discoloration after bleaching D1 96.89 -0.28 5.13 85.8 DP * D before bleaching 97.89 -0.47 2.96 90.8 DP * D after bleaching 96.06 -0.55 8.01 80,4 10,4 1.92

Cellulose from southern pine wood was obtained in step D2 from the same plant as described above with the same initial viscosity, measured by capillary method using CED, and treated with hydrogen peroxide in the presence of Fe (II) as described above. Hydrogen peroxide was added in an amount of 1.5% based on the dry weight of cellulose in the presence of 150 ppm Fe (II). The properties of this treated pulp are presented in table 24.

Table 24 Stage Chemicals Added pH Capillary viscosity using a CED viscosity of 0.5% solution Δ Change in viscosity DPw White Length-weighted average fiber length % in relation to the mass of cellulose final value mPa⋅s % ISO mm D2 14.1 1960 90.2 P * 1.5% H ₂ O ₂ 150 ppm Fe ⁺² 2,8 3,5 10.6 485 86.8 2.17

Cellulose P * was investigated in relation to the restoration of whiteness, as described above. The results are presented below in table 25.

Table 25 Whiteness restoration Stage L * a * b * White Δ Change in whiteness Discoloration after bleaching D2 before bleaching 98.34 -0.61 2.54 92.54 D2 before bleaching 97.87 -0.57 3.67 89.92 2.62 0.26 DP (EP) DP * before bleaching 97.39 -0.47 4.49 87.68 DP (EP) DP * after bleaching 95.25 -0.34 9.78 76.45 11,2 2.76

As can be seen from the above data, the catalyzed peroxide treatment in an acidic medium in the fourth stage of the five-stage bleaching process compared to the treatment after the final stage of the five-stage bleaching process provides beneficial whitening properties. In the fourth processing step, any loss of whiteness during the processing can be compensated for in the final stage of bleaching D2, so that in any case cellulose having a high degree of brightness is obtained. In the case of treatment after bleaching, a significant loss of whiteness is observed, amounting to 3.4 points, which cannot be compensated. After accelerated processing in order to restore brightness in the latter case, a significantly lower degree of brightness is still obtained.

Example 23. Strength data

The strength of fluff pulp made from modified cellulose having a viscosity of 5.1 MPa · s according to the present invention was compared with the strength of conventional fluff pulp having a viscosity of 15.4 MPa · s. The results are presented below in table 26.

Table 26 Control fluff pulp Modified Pulp The surface density after drying in air, g / m ² 65.12 68.15 The surface density after drying in the oven, g / m ² 60.56 63.38 The degree of grinding CSF, ml 732 717 Thickness, 0.001 inches 4.88 5.09 Specific volume, cm ³ / g 1.90 1.90 Bulk density, g / cm ³ 0.53 0.53 Porosity in air, s / 100 ml 0.59 0.67 Burst resistance index, (g / cm ² ) / (g / m ² 16.6 14.0 The gap coefficient, gs⋅m ² / g 242 198 Breaking length, km 2,52 2.49 Tensile% 2.76 2.48 Opacity,% 72.1 73.5 Mud and bonfire, mm ² / m ² 0.3 1,5 Viscosity, cP 15.4 5.1 ISO whiteness 88.9 88.9 Frazier porosity, cc feet per minute 45.4 55.1 Fiber length mm 2,636 2,661 Form factor,% 85.8 85.8

Example 24. Obtaining derivatives of modified cellulose

Sample ULDP from example 21 was subjected to acid hydrolysis using a solution of 0.05 M HCl at a consistency of 5% for 3 hours at 122 ° C. The starting cellulose after step D1, ULDP cellulose and acid hydrolyzed ULDP cellulose were examined to determine the average molecular weight or degree of polymerization as described below.

Three cellulose samples were ground and sieved through a sieve with a mesh size of 20 mesh (0.853 mm). Cellulose samples weighing 15 mg were placed in separate tubes equipped with micromixers, and dried overnight in vacuum at 40 ° C. The tubes were then closed with rubber diaphragms. Anhydrous pyridine (4.00 ml) and phenylisocyanate (0.50 ml) were added sequentially using a syringe. The tubes were placed in an oil bath at 70 ° C and kept stirring for 48 hours. Methanol (1.00 ml) was added to neutralize any remaining phenylisocyanate. The contents of each tube were then added dropwise in 100 ml of a 7: 3 mixture of methanol and water to facilitate the precipitation of the cellulose derivatives. The solid was collected by filtration, and then washed with a mixture of methanol and water (once 50 ml) and then with water (2 times 50 ml). The cellulose derivatives were then dried overnight in vacuo at 40 ° C. Before analysis by gel permeation chromatography (GPC), cellulose derivatives were dissolved in THF tetrahydrofuran in an amount of 1 mg / ml, the solution was filtered through a filter with a hole size of 0.45 μm and placed in a 2 ml tank of an automatic sampler. The resulting values of the weight average degree of polymerization (DPw) and number average degree of polymerization (DPn) are presented below in table 27.

Table 27 The results of the study of the number average degree of polymerization (DPn) and the weight average degree of polymerization (DPw) Sample Mn (g / mol) Mw (g / mol) Dpn DPw D1 1.4601e5 2,2702e6 281 4374 DLDP 4.0775e4 7.4566e5 78 1436 Acid Hydrolyzed Cellulose ULDP 2,525e4 1.8966e5 48 365

As can be seen in the above table, the modified cellulose after acid hydrolysis according to the present invention can have a DPn value of 48.

Example 25

Using Leaf River ULDP fibers and standard coniferous fibers, hand-cast sheets were made by suspending the fiber, adjusting the pH to about 5.5, and then adding glyoxylated polyacrylamide as a temporary wet strength agent from Kemira Chemicals. After that, the fibers were formed, the sheets were pressed and dried. The characteristics of the sheets were measured by known methods. The results are presented below in table 28.

Table 28 Hand Casting Sheet Properties LR SW (control sample) ULDP TWS #T 0 10 twenty 40 0 10 twenty 40 Titrated charge ml / 10 ml 10-3n -0.166 +0.204 +0.389 +2,899 -0.143 -0.134 +0.474 +1,919 Surface density # / R 15.11 16.19 15,59 14.64 15.75 14.83 13.08 15.3 g / m ² 24.59 26.35 25.37 23.83 25.63 24.14 21.29 24.9 Volume Single layer thickness, mil 3.68 3.78 3.80 4.04 3.80 3.72 4.12 4.08 Specific volume, cm ³ / g 3.80 3.64 3.80 4.31 3.77 3.91 4.92 4.16 Dry Stretch Stretch g / inch 747 1335 1187 1118 716 825 866 864 Breaking length, km 1,196 1,995 1,842 1,847 1,100 1,346 1,602 1,366 Tensile% 2.6 3.2 2.9 3.0 2.2 2.7 3.3 2.9 Tensile energy consumption (TEA), mm⋅g / mm ² 0.10 0.28 0.21 0.21 0.06 0.11 0.17 0.12 Wet stretching Stretch g / inch four 209 218 256 23 148 200 168 Breaking length, km 0.0064 0.3123 0.3383 0.423 0,0353 0.2414 0.3699 0.2656 Sat Capacity, g / m ² 205.9 194.7 187.0 190.9 185.0 173.0 182.0 202.0 Speed g / s ^0.5 0.06 0.08 0,07 0.05 0.08 0,07 0,07 0.10 Time s 89.6 59.1 59.2 83.8 55.5 50,0 57.7 49.9 Wet / Dry Ratio one% 16% eighteen% 23% 3% eighteen% 23% 19%

As can be seen in Table 28 above, the ULDP fibers of the present invention can be used in the manufacture of wet-pressed paper. As shown in FIG. 2, the wet / dry ratio of hand-cast sheets made from ULDP fibers is more than the wet / dry ratio of comparative sheets made only from standard southern pine softwood fibers.

Example 26

Ultrafine fluffy fluffy core samples were prepared using standard and modified sulfate fibers having a surfactant-treated upper and lower layers and an untreated middle layer. Table 29 describes the configuration of the fabricated samples of the ultrafine fluffy core. The results are presented in Table 30. The tests were performed by Testing Service (Kalamazoo, Michigan, USA), using its own equipment and procedures for research. The tensile strength and percent elongation were determined for each product in the machine direction using the distance between the clamps of 5.00 cm, a sample 1.3 cm wide, the speed of the transverse head 2.5 cm / min and a load sensor of 30 kg If indicated, standard fiber was processed using TQ-2021, and modified sheets were processed using TQ-2028, both of which were surfactants supplied by Ashland, Inc. The absorption of the fluid was carried out by placing 5 ml of 0.9% saline solution on the sample and keeping the fluid for 5 minutes. After 5 minutes, re-wetting was carried out for 2 minutes using standard laboratory filter paper.

Table 29 Layer one 2 3 four 5 Surfactant treated topcoat Standard fiber Standard fiber Modified substance Modified substance Modified substance Raw middle layer Standard fiber Standard fiber Modified substance Modified substance Standard fiber Surfactant treated bottom layer Standard fiber Modified substance Modified substance Standard fiber Standard fiber

Table 30 Property one 2 3 four 5 Results for Defibrinated Bovine Blood Re-wetting Gms 0.37 0.38 0.38 0.32 0.33 Average thickness change % 29.2 26.8 26.5 25,4 25.8 Average estimated total capacity Gms 7.86 7.81 7.77 7.61 7.62 Average absorption time c 25.0 26.6 18.2 26.0 27.6 Other results Protective covering cm 5.1 6.2 6.8 6.4 5.8 The average change in thickness with saline % 236.9 169.2 176.7 154.7 153.9 Dry tensile strength Elongation (%) 7.56 7.89 8.59 9.60 9.56 Dry tensile strength Tensile Energy Consumption (TEA) (J / m ² ) 34,807 34,585 33,700 48.128 46,008 Wet tensile strength Elongation (%) 15.78 16.67 18,20 20.62 20.78 Wet tensile strength Tensile Energy Consumption (TEA) (J / m ² ) 16,268 19,247 19,900 28,268 28,799

As can be seen in Table 30 above, absorbent articles made using the surfactant-treated fibers of the present invention had improved flexibility, increased dimensional stability, higher strength and deformation in wet and dry conditions, and improved re-wettability .

Other embodiments of the invention

Although the presently desirable inventions of the applicants are defined in the attached claims, it should be understood that the present invention can also be defined in accordance with the following embodiments, which are not necessarily exclusive or restrictive with respect to the claimed claims:

A. Fiber, the source of which is bleached softwood or deciduous sulfate cellulose, wherein the fiber measured by capillary method using CED, the viscosity of a 0.5% solution is approximately 13 mPa⋅s or less, preferably less than about 10 mPa⋅s, more preferably less than 8 mPa⋅s, even more preferably less than about 5 mPa⋅s or even more preferably less than about 4 mPa⋅s.

B. Fiber, the source of which is bleached softwood sulfate cellulose, wherein the fiber has an average fiber length of at least about 2 mm, preferably at least about 2.2 mm, for example at least about 2, 3 mm or, for example, at least about 2.4 mm, or, for example, about 2.5 mm, more preferably from about 2 mm to about 3.7 mm, and even more preferably from about 2.2 mm to about 3.7 mm

C. Fiber, the source of which is bleached hardwood sulphate cellulose, wherein the fiber has an average fiber length of at least about 0.75 mm, preferably at least about 0.85 mm, or at least about 0 95 mm, or more preferably at least about 1.15, or from about 0.75 mm to about 1.25 mm.

D. Fiber, the source of which is bleached softwood sulfate cellulose, wherein the fiber measured by capillary using CED with a viscosity of 0.5% solution is approximately 13 mPa⋅s or less, the average fiber length is at least about 2 mm, and ISO whiteness is from about 85 to about 95.

E. Fiber according to any one of embodiments AD, wherein the viscosity is from about 3.0 mPa⋅s to about 13 mPa⋅s, for example, from about 4.5 mPa⋅s to about 13 mPa⋅s, preferably from about 7 mPa⋅s to about 13 mPa⋅s or, for example, from about 3.0 mPa⋅s to about 7 mPa⋅s and preferably from about 3.0 mPa⋅s to about 5.5 mPa⋅s.

F. Fiber according to options for implementation A-D, in which the viscosity is less than about 7 MPa · s.

G. Fiber according to options for implementation A-D, in which the viscosity is at least about 3.5 MPa · s.

H. Fiber according to embodiments A-D, wherein the viscosity is less than about 4.5 mPa · s.

I. Fiber according to options for implementation A-D, in which the viscosity is at least about 5.5 MPa · s

J. A fiber according to Embodiment E wherein the viscosity is not more than about 6 mPa · s.

K. A fiber according to one of the aforementioned embodiments, wherein the viscosity is less than about 13 mPa · s.

L. A fiber according to one of embodiments A-B and D-K, in which the average fiber length is at least about 2.2 mm.

M. A fiber according to one of embodiments A-B and D-L, in which the average fiber length is not more than about 3.7 mm.

N. A fiber according to one of the embodiments A-M, wherein the fiber has an alkali solubility of S10 from about 16% to about 30% and preferably from about 16% to about 20%.

O. The fiber according to one of the embodiments A-M, and this fiber has a solubility in alkali S10, comprising from about 14% to about 16%.

P. A fiber according to one of the embodiments A-O, wherein the fiber has an alkali solubility S18 of about 14% to about 22%, preferably from about 14% to about 18%, and more preferably from about 14% to about 16%.

Q. The fiber according to one of the embodiments A-P, and this fiber has a solubility in alkali S18, comprising from about 14% to about 16%.

R. A fiber according to one of embodiments A-Q, wherein the fiber has a ΔR value of about 2.9 or more.

S. A fiber according to one of the embodiments A-Q, wherein the fiber has a ΔR value of about 3.0 or more, preferably about 6.0 or more.

T. A fiber according to one embodiment of AS, wherein the fiber has a carboxyl group content of from about 2 meq / 100 g to about 8 meq / 100 g, preferably from about 2 meq / 100 g to about 6 meq / 100 g and more preferably about 3 meq / 100 g to about 6 meq / 100 g

U. A fiber according to one of embodiments A-S, the fiber having a carboxyl group content of at least about 2 meq / 100 g.

V. A fiber according to one of embodiments A-S, wherein the fiber has a carboxyl group content of at least about 2.5 meq / 100 g.

W. A fiber according to one of the embodiments A-S, the fiber having a carboxyl group content of at least about 3 meq / 100 g.

X. A fiber according to one of embodiments A-S, wherein the fiber has a carboxyl group content of at least about 3.5 meq / 100 g.

Y. A fiber according to one of embodiments A-S, wherein the fiber has a carboxyl group content of at least about 4 meq / 100 g.

Z. A fiber according to one of embodiments A-S, wherein the fiber has a carboxyl group content of at least about 4.5 meq / 100 g.

AA. A fiber according to one of embodiments A-S, wherein the fiber has a carboxyl group content of at least about 5 meq / 100 g.

BB. A fiber according to one of embodiments A-S, wherein the fiber has a carboxyl group content of about 4 meq / 100 g.

CC. A fiber according to one embodiment of A-BB, wherein the fiber has an aldehyde group content of from about 1 meq / 100 g to about 9 meq / 100 g, preferably from about 1 meq / 100 g to about 3 meq / 100 g

DD. A fiber according to one of the A-BB embodiments, the fiber having an aldehyde group content of at least about 1.5 meq / 100 g.

EE.

Ff. A fiber according to one of the A-BB embodiments, the fiber having an aldehyde group content of at least about 2.0 meq / 100 g.

Gg. A fiber according to one of the A-BB embodiments, the fiber having an aldehyde group content of at least about 2.5 meq / 100 g.

Hh. A fiber according to one of the A-BB embodiments, the fiber having an aldehyde group content of at least about 3.0 meq / 100 g.

II. A fiber according to one of the A-BB embodiments, the fiber having an aldehyde group content of at least about 3.5 meq / 100 g.

JJ. A fiber according to one of the A-BB embodiments, wherein the fiber has an aldehyde group content of at least about 4.0 meq / 100 g.

KK. A fiber according to one of the A-BB embodiments, the fiber having an aldehyde group content of at least about 5.5 meq / 100 g.

LL. A fiber according to one of the A-BB embodiments, wherein the fiber has an aldehyde group content of at least about 5.0 meq / 100 g.

MM A fiber according to one embodiment of A-MM, wherein the fiber has a copper number determined by copper number of more than about 2, preferably more than about 2.5, more preferably more than about 3, or copper content of carbonyl groups a number that is from about 2.5 to about 5.5, preferably from about 3 to about 5.5, more preferably from about 3 to about 5.5, or the fiber has soda neigh carbonyl groups defined copper number that ranges from about 1 to about 4.

NN. A fiber according to one of the embodiments A-NN, in which the content of carbonyl groups is from about 2 to about 3.

OO. A fiber according to one embodiment of A-NN, the fiber having a copper number of about 3 or more, determined by the copper number.

PP A fiber according to one of the A-NN embodiments, the fiber having a ratio of total carbonyl groups to aldehyde groups of from about 0.9 to about 1.6.

QQ. A fiber according to one of the embodiments A-NN, in which the ratio of the total content of carbonyl groups to the content of aldehyde groups is from about 0.8 to about 1.0.

RR. A fiber according to one of the aforementioned embodiments, wherein the fiber has a Canadian standard milling degree (“milling degree”) of at least about 690 ml, preferably at least about 700 ml, more preferably at least approximately 710 ml or, for example, at least approximately 720 ml or approximately 730 ml.

SS. A fiber according to one of the aforementioned embodiments, the fiber having a degree of milling of at least about 710 ml.

TT. A fiber according to one of the aforementioned embodiments, the fiber having a degree of milling of at least about 720 ml.

UU. A fiber according to any of the aforementioned embodiments, the fiber having a degree of milling of at least about 730 ml.

VV. A fiber according to one of the aforementioned embodiments, the fiber having a milling degree of not more than about 760 ml.

WW. A fiber according to one of the A-WW embodiments, the fiber having a fiber strength, the measure of which is the breaking length in the wet state at a zero distance between the clamps of about 4 km to about 10 km.

XX. A fiber according to one of the A-WW embodiments, the fiber having a fiber strength of about 5 km to about 8 km.

Yy A fiber according to one of the A-WW embodiments, the fiber having a fiber strength, the measure of which is the breaking length in the wet state at zero distance between the clamps, at least about 4 km.

Zz. A fiber according to one of the A-WW embodiments, the fiber having a fiber strength, the measure of which is the breaking length in the wet state at zero distance between the clamps, at least about 5 km.

AAA. A fiber according to one of the A-WW embodiments, the fiber having a fiber strength, the measure of which is the breaking length in the wet state at zero distance between the clamps, at least about 6 km.

BBB A fiber according to one of the A-WW embodiments, the fiber having a fiber strength, the measure of which is the breaking length in the wet state at zero distance between the clamps, at least about 7 km.

CCC A fiber according to one of the embodiments of A-WW, wherein the fiber has a fiber strength, the measure of which is the breaking length in the wet state at zero distance between the clamps, at least about 8 km.

DDD A fiber according to one of the A-WW embodiments, the fiber having a fiber strength, the measure of which is the breaking length in the wet state at a zero distance between the clamps of about 5 km to about 7 km.

EEE. A fiber according to one of the A-WW embodiments, the fiber having a fiber strength, the measure of which is the breaking length in the wet state at a zero distance between the clamps of about 6 km to about 7 km.

FFF A fiber according to one of the aforementioned embodiments, wherein the ISO whiteness is from about 85 to about 92, preferably from about 86 to about 90, more preferably from about 87 to about 90, or from about 88 to about 90 ISO.

GGG. A fiber according to one of the aforementioned embodiments, wherein the ISO whiteness is at least about 85, preferably at least about. 86, more preferably at least about 87, in particular at least about 88, more specifically at least about 89 or about 90 ISO.

Hhh. A fiber according to one of the embodiments of A-FFF, in which the whiteness according to the ISO standard is at least about 87.

III. A fiber according to one of the embodiments of A-FFF, in which the whiteness according to the ISO standard is at least about 88.

JJJ. A fiber according to one of the embodiments of A-FFF, in which the whiteness according to the ISO standard is at least about 89.

KKK. A fiber according to one of the embodiments of A-FFF, in which the whiteness according to the ISO standard is at least about 90.

Lll. A fiber according to any of the aforementioned embodiments, wherein the fiber is approximately the same length as a standard sulfate fiber.

MMM A fiber according to one of the embodiments A-S and SS-MMM having a higher content of carboxyl groups than standard sulfate fiber.

NNN. A fiber according to one of the embodiments A-S and SS-NNN having a higher aldehyde content than standard sulfate fiber.

OOO. A fiber according to embodiments AS and SS-MMM, in which the ratio of total aldehyde group to carboxyl group is more than about 0.3, preferably more than about 0.5, more preferably more than about 1.4, or, for example, is from about 0.3 to about 0.5, or from about 0.5 to about 1, or from about 1 to about 1.5.

PPP A fiber according to any of the aforementioned embodiments having a higher bending index than a standard sulfate fiber, for example, having a bending index of from about 1.3 to about 2.3, preferably from about 1.7 to about 2.3, more preferably from about 1.8 to about 2.3; or from about 2.0 to about 2.3.

QQQ. A fiber according to any of the aforementioned embodiments, having a length-weighted crimp index of from about 0.11 to about 0.2, and preferably from about 0.15 to about 0.2.

RRR A fiber according to any of the aforementioned embodiments having a lower crystallinity index than a standard sulfate fiber, for example, a crystallinity index whose reduction is from about 5% to about 20% with respect to a standard sulfate fiber, preferably from about 10% to about 20% preferably 15% to 20% with respect to standard sulfate fiber.

SSS. A fiber according to any one of the above embodiments, wherein the R10 value is from about 65% to about 85%, preferably from about 70% to about 85%, more preferably from about 75% to about 85%.

TTT. A fiber according to any one of the above embodiments, wherein the R18 value is from about 75% to about 90%, preferably from about 80% to about 90%, and more preferably from about 80% to about 87%.

UUU. A fiber according to any of the aforementioned embodiments, the fiber having odor limiting properties.

VVV. A fiber according to any of the aforementioned embodiments, wherein the fiber reduces the concentration of ammonia in the atmosphere by at least 40% more, preferably at least about 50% more, more preferably at least about 60% more, in particular at least about 70% more, or at least about 75% more, more specifically at least about 80% more, or about 90% more than standard sulfate fiber.

WWW. A fiber according to any one of the above embodiments, wherein the fiber absorbs from about 5 to about 10 parts per million ammonia per gram of fiber, preferably from about 7 to about 10 parts per million, and more preferably from about 8 to about 10 parts per million ammonia per gram fiber.

XXX A fiber according to any one of the aforementioned embodiments, wherein the fiber has a cytotoxicity test result of a minimum support medium of less than 2, preferably less than about 1.5, and more preferably less than about 1.

Yyy. A fiber according to any of the above embodiments, wherein the copper number is less than 2, preferably less than 1.9, more preferably less than 1.8, and even more preferably less than 1.7.

ZZZ. A fiber according to any one of embodiments A-YYY, wherein the permanganate number is from about 0.1 to about 1, preferably from about 0.1 to about 0.9, more preferably from about 0.1 to about 0.8, for example from about 0.1 to about 0.7, or from about 0.1 to about 0.6, or from about 0.1 to about 0.5, and more preferably from about 0.2 to about 0.5.

AAAA. A fiber according to any of the aforementioned embodiments having substantially the same hemicellulose content as standard sulfate fiber, which, for example, is from about 16% to about 18% when the fiber is coniferous fiber, or from about 18% to about 25% when the fiber is a deciduous fiber.

BBBB A fiber according to any of the aforementioned embodiments, wherein the fiber exhibits antimicrobial and / or antiviral activity.

. A fiber according to any of the embodiments BC or L-Priv, in which the degree of polymerization is from about 350 to about 1860, for example, from about 710 to about 1860, preferably from about 350 to about 910, or, for example, from about 1160 to about 1860 .

DDDD A fiber according to any one of embodiments B-C or L-Priv, in which the degree of polymerization is less than about 1860, preferably less than about 1550, more preferably less than about 1300, more preferably less than about 820 or less than about 600.

EEEE. A fiber according to any of the aforementioned embodiments, wherein the fiber is more compressible and / or embossable than standard sulfate fiber.

FFFF. A fiber according to embodiments of A-OOO, wherein the fiber can be compressed to a density of at least about 0.210 g / cm ³ , preferably at least about 0.220 g / cm ³ , more preferably at least about 0.230 g / cm ³ , in particular at least about 0.240 g / cm ³ .

GGGG. A fiber according to embodiments of A-OOO, wherein the fiber can be compressed to a density of at least about 8% more than the density of a standard sulfate fiber, in particular more than a density of a standard sulfate fiber, where the difference is from about 8 % to about 16%, preferably from about 8% to about 10%, or from about 12% to about 16%, more preferably from about 13% to about 16%, more preferably from about flax 14% to about 16% and, in particular, from about 15% to about 16%.

A number of embodiments have been described above. However, it should be understood that various modifications can be made without deviating from the idea and going beyond the scope of the present invention. Accordingly, other embodiments are within the scope of the following claims.

Claims (28)

1. A method of manufacturing an absorbent core for hygiene products having increased embossability, including: the inclusion in the core of sulfate fiber, which was oxidized with peroxide in the presence of a copper or iron catalyst in an acidic medium according to the bleaching sequence to obtain a bleached sulfate fiber, characterized by the content of aldehyde groups ranging from 1 meq / 100 g to 9 meq / 100 g, carboxyl content groups of at least 3 meq / 100 g, measured by the capillary method using a CED with a viscosity of 0.5% solution of less than 10 mPa⋅s, and which was additionally brabotano surfactant, in which the sulfate fiber exhibits an increase in the specific absorption rate of less than 30% after application of the surfactant. 2. The method according to p. 1, in which the surfactant is a baking powder or softener. 3. The method of claim 1, wherein the surfactant is a cationic surfactant. 4. The method according to claim 1, in which one or more ethoxylated nonylphenol ethers and quaternary ammonium salts of vegetable fatty acids are selected as a surfactant. 5. The method according to claim 4, in which the sulfate fiber exhibits an increase in the specific absorption rate of less than 25% after application of the surfactant. 6. The method according to p. 4, in which the fiber is oxidized in the fourth stage of the five-stage bleaching sequence. 7. The method of claim 1, wherein the fiber has an average fiber length of at least 2 mm. 8. Absorbent core for hygiene products, which contains at least three regions of the fiber, the first region, the second region and the third region, and in normal use, the first region comes into contact with the fluid earlier than the second region, and the second region comes into contact with the fluid earlier than the third region , in which at least one of the core regions contains an oxidized sulfate fiber characterized by an aldehyde group content of 1 meq / 100 g to 9 meq / 100 g, a carboxyl group content of at least 3 meq / 100 g measured by the capillary method using a CED with a viscosity of 0.5% solution of less than 10 mPa · s, and which was treated with a surfactant. 9. The core of claim 8, wherein the surface-active oxidized sulfate fiber is present in the first or third regions of the core. 10. The core of claim 8, wherein the surface-active oxidized sulfate fiber is present in at least two core regions. 11. The core of claim 10, wherein the oxidized fiber treated with the surfactant is present in at least the first and second regions of the core. 12. The core of claim 8, wherein the surface-active oxidized sulfate fiber is present in at least three core regions. 13. The core according to claim 8, in which one or more ethoxylated nonylphenol ethers and quaternary ammonium salts of vegetable fatty acids are selected as a surfactant. 14. The core of claim 13, wherein the sulfate fiber exhibits an increase in specific absorption rate of less than 30% after application of a surfactant. 15. Fluff pulp for the absorbent core of hygiene products, containing bleached softwood sulfate fiber, characterized by an aldehyde content of 1 meq / 100 g to 9 meq / 100 g, a carboxyl group of at least 3 meq / 100 g measured by a capillary method using a CED with a viscosity of 0.5% solution of less than 10 mPa⋅s, ISO has a whiteness of at least 88, and a length-weighted average fiber length of at least 2 mm, this fiber was arr Botan surfactant. 16. The cellulose of claim 15, wherein the surfactant is a disintegrant or a softener. 17. The cellulose of claim 15, wherein the surfactant is a cationic surfactant. 18. The cellulose according to claim 15, wherein one or more ethoxylated nonylphenol ethers and quaternary ammonium salts of vegetable fatty acids are selected as a surfactant. 19. The cellulose of claim 18, wherein the sulfate fiber exhibits an increase in specific absorption rate of less than 30% after application of the surfactant. 20. Fluff pulp for an absorbent core of hygiene products containing sulphate fiber made by bleaching cellulosic sulphate pulp using a multi-stage bleaching and oxidation process of sulphate pulp during at least one stage of a multi-stage bleaching process with peroxide in the presence of a catalyst in an acidic environment this multi-stage bleaching process includes at least one chlorine dioxide bleaching stage after the oxide stage yielding a bleached sulfate fiber characterized by an aldehyde group content of 1 meq / 100 g to 9 meq / 100 g, a carboxy group content of at least 3 meq / 100 g, measured by a capillary method using a CED viscosity of 0 , 5% solution of less than 10 mPaПs, moreover, this fiber is treated with one or more surfactants, and the sulfate fiber exhibits an increase in the specific absorption rate of less than 30% after application of the surfactant. 21. The cellulose of claim 20, wherein the surfactant is a disintegrant or a softener. 22. The cellulose of claim 20, wherein the surfactant is a cationic surfactant. 23. Cellulose according to claim 20, in which one or more ethoxylated nonylphenol ethers and quaternary ammonium salts of vegetable fatty acids are selected as surfactant.

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