TW201443314A - Modified cellulose from chemical kraft fiber and methods of making and using the same - Google Patents

Abstract

Urine absorbing devices having a modified kraft pulp fiber with unique properties is provided. The kraft fiber is made from a method having at least one acidic, iron catalyzed peroxide treatment process that can be incorporated into at least one stage of a multi-stage bleaching process. The products can be diapers, incontinence products and other urine absorbing devices.

Description

Modified cellulose derived from chemical kraft fiber and method of making and using same

This application is part of the continuation application of U.S. Application Serial No. 13/314,493, filed on Dec. 8, 2011, and U.S. Application Serial No. 13/314,493, filed on November 23, 2011 Continuing application No. 322,419, US application No. 13/322,419 entered the national phase under PCT International Application No. PCT/US2010/036763, filed on May 28, 2010 under 35 USC § 371, and The application claims the priority and the benefit of the filing date of the U.S. Provisional Application No. 61/182,000, filed on May 28, 2009, the entire disclosure of which is incorporated herein by reference.

The present disclosure relates to chemical modification of cellulosic fibers. More particularly, the present disclosure relates to chemically modified cellulosic fibers derived from bleached kraft pulp which exhibit a unique set of properties that improve the performance and make them useful for standard cellulosic fibers derived from kraft pulp. It has hitherto been limited to expensive fiber applications (such as cotton or high alpha cellulose content sulfite pulp). In particular, the chemically modified bleached kraft fiber can exhibit one or more of the following beneficial properties including: improved odour control, improved compression, and/or improved brightness. The chemically modified bleached kraft fiber can exhibit one or more of these beneficial properties while also maintaining one or more other characteristics of the non-chemically modified bleached kraft fiber (e.g., maintaining fiber length and/or freeness).

The present disclosure further relates to chemically modified cellulosic fibers derived from bleached softwood and/or hardwood kraft pulp which exhibit low or ultra-low degree of polymerization, making them suitable for use. It is used as a fluff pulp in absorbent products, as a chemical cellulose raw material for producing cellulose derivatives (including cellulose ethers and esters) and for use in consumer products. As used herein, "degree of polymerization" may be abbreviated as "DP". The present disclosure is additionally directed to cellulose having a stable degree of polymerization of less than about 80 derived from chemically modified kraft fiber. More specifically, the chemically modified kraft fiber exhibiting low or ultra-low degree of polymerization (referred to herein as "LDP" or "ULDP") as described herein can be further treated by acid or base hydrolysis to further reduce the degree of polymerization. To less than about 80 (e.g., to less than about 50), making it suitable for a variety of downstream applications.

The present disclosure is also directed to a method of producing the modified fibers described. The present disclosure provides, in part, a method of simultaneously increasing the carboxylic acid and aldehyde functionality of kraft fiber. The described fibers are subjected to catalytic oxidation treatment. In some embodiments, the fibers are oxidized using iron or copper and then further bleached to provide fibers having beneficial brightness characteristics, such as brightness comparable to standard bleached fibers. Additionally, at least one process is disclosed which provides the above-described improved beneficial properties and does not introduce the additional cost steps for post-treating bleached fibers. In this less costly embodiment, the fibers can be treated in a single stage of a kraft process, such as a kraft bleach process. Another embodiment relates to a 5-stage bleaching process comprising the sequence D ₀ E1D1E2D2, wherein the fourth stage (E2) comprises a catalytic oxidation treatment.

Finally, the present disclosure relates to consumer products, cellulose derivatives (including cellulose ethers and esters), and microcrystalline cellulose, all produced using the chemically modified cellulose fibers described.

Cellulose fibers and derivatives are widely used in paper, absorbent products, food or food related applications, pharmaceutical and industrial applications. The main sources of cellulose fibers are wood pulp and cotton. Cellulosic sources and cellulosic processing conditions generally determine the characteristics of the cellulosic fibers and thereby determine the suitability of the fibers for certain end uses. There is a need for cellulosic fibers that can be processed relatively inexpensively but are highly versatile such that they can be used in a variety of applications.

Cellulose is usually stored in the form of a polymer chain comprising hundreds to tens of thousands of glucose units. in. Various methods of oxidizing cellulose are known. In cellulose oxidation, the hydroxyl group of the glycoside of the cellulose chain can be converted to, for example, a carbonyl group (e.g., an aldehyde group or a carboxylic acid group). The type, extent and location of the carbonyl modification may vary depending on the oxidation method and conditions employed. Certain oxidative conditions are known to depolymerize, for example, by cleavage of the glycoside ring in the cellulose chain to degrade the cellulose chain itself. In most cases, the depolymerized cellulose not only has a reduced viscosity, but also has a fiber length shorter than the starting cellulosic material. When cellulose (eg, by depolymerization and/or significantly reducing fiber length and/or fiber strength) undergoes degradation, it can be difficult to handle and/or may not be suitable for many downstream applications. There remains a need for cellulosic fiber modification processes that modify carboxylic acid and aldehyde functionality that do not extensively degrade cellulose fibers. The present disclosure provides a unique method of addressing one or more of these deficiencies.

Various attempts have been made to oxidize cellulose to provide carboxylic acid and aldehyde functionality to the cellulose chains without degrading the cellulose fibers. In conventional cellulose oxidation processes, it may be difficult to control or limit the degradation of cellulose when the aldehyde groups are present on the cellulose. Previous attempts to address these issues have involved the use of multi-step oxidation processes (eg, modifying certain carbonyl groups in one step and oxidizing other hydroxyl groups in another step) and/or providing mediators and/or protectants, all of which may be Provides additional cost and by-products to the cellulose oxidation process. Thus, there is a need for a cellulose modification process that is cost effective and/or can be practiced in a single step of a process such as a kraft process.

The present disclosure provides novel methods that have significant improvements over the methods tried in the prior art. Typically, in the prior art, the oxidation of cellulose kraft fibers is carried out after the bleaching process. Surprisingly, the inventors have discovered that the cellulose fiber can be oxidized using the existing stage of the bleaching sequence, especially the fourth stage of the 5-stage bleaching sequence. In addition, it is surprising that the inventors have discovered that metal catalysts (especially iron catalysts) can be used in the bleaching sequence to achieve this oxidation without interfering with the final product, for example because the catalyst is not The binding remains in the cellulose such that at least some of the residual iron is removed earlier than expected based on industry knowledge prior to the end of the bleaching sequence. Additionally, surprisingly, the inventors have discovered that such methods can be practiced without substantially degrading the fibers.

It is known in the art that metals and peroxides and/or peracids can be used to oxidize cellulosic fibers (including kraft pulp). For example, iron and peroxide ("Fenton's reagent") can be used to oxidize cellulose. See Kishimoto et al., Holzforschung, Vol. 52, No. 2 (1998), pp. 180-184. Metals and peroxides (e.g., Fenton's reagent) are relatively inexpensive oxidants, making them desirable for large-scale applications (e.g., kraft process) to some extent. In the case of Fenton's reagent, this oxidation process is known to degrade cellulose under acidic conditions. Therefore, it is expected that Fenton's reagent will not be used in the kraft process under acidic conditions and will extensively degrade the fiber, for example with a loss of fiber length. To prevent cellulose degradation, Fenton's reagent is usually used under alkaline conditions, in which the Fenton reaction is significantly inhibited. However, there are other disadvantages when using Fenton's reagent under alkaline conditions. For example, cellulose can still degrade or fade. In kraft pulp processing, cellulosic fibers are typically bleached in a multi-stage sequence, which typically includes a strong acid and strong alkaline bleaching step wherein at least one alkaline step is included at or near the end of the bleaching sequence. Thus, contrary to what is known in the art, it is quite surprising that the use of iron to oxidize fibers during the acidic phase of the kraft bleaching process results in fibers having enhanced chemical properties but no physical degradation or fading.

Thus, there is a need for low cost and/or single step oxidation which imparts aldehyde and carboxylic acid functionality to cellulosic fibers (e.g., fibers derived from kraft pulp) and does not extensively degrade cellulose and/or render cellulose unsuitable for use. Many downstream applications. In addition, there is still a need to impart high levels of carbonyl groups to the cellulosic fibers, such as carboxylic acid, ketone and aldehyde groups. For example, unlike the use of Fenton's reagent at alkaline pH, it is desirable to use an oxidizing agent to, for example, impart a high level of carbonyl groups without inhibiting the oxidation reaction. The inventors have overcome many of the difficulties of the prior art to provide a method of meeting such needs.

In addition to the difficulties in controlling the chemical structure of cellulose oxide products and the degradation of their products, it is known that oxidation processes can affect other properties, including chemical and physical properties and/or impurities in the final product. For example, oxidation methods can affect crystallinity, hemicellulose content The amount, color and/or content of impurities in the final product. Finally, the oxidation process can affect the ability to process cellulosic products for industrial or other applications.

Wood pulp is typically bleached by selectively increasing the whiteness or brightness of the pulp (usually by removing lignin and other impurities) without adversely affecting the physical properties. Bleaching of chemical pulps, such as kraft pulp, typically requires several different bleaching stages to achieve the desired brightness with good selectivity. Typically, the bleaching sequence is carried out at a stage of alternating pH ranges. This altering helps to remove impurities formed in the bleaching sequence, for example, by dissolving the lignin decomposition product. Thus, in general, it is expected that the use of a series of acidic stages (e.g., a sequence of three acidic stages) in a bleaching sequence will not provide the same brightness as an alternating acidic/basic stage (e.g., acidic-alkaline-acidic). For example, a typical DEEDED sequence produces a product that is brighter than the DEDAD sequence (wherein A refers to acid treatment). Thus, a sequence that does not have an intermediate basic phase still produces a product of equal brightness, which is not expected by those skilled in the art.

In general, although certain bleaching sequences are known to have advantages over other sequences in the kraft process, the reasons behind any of the advantages are not fully understood. In the case of oxidation, no studies have shown any oxidative preference in a particular stage of a multi-stage sequence or any knowledge that the fiber properties can be affected by the post-oxidation stage/treatment. For example, the prior art does not disclose any prioritization of oxidation in the later stages of oxidation at a later stage. In some embodiments, the present disclosure provides a uniquely implemented method at a particular stage (eg, a post-bleaching stage) that benefits the kraft process and results in a fiber having a unique set of physical and chemical properties.

Furthermore, in terms of brightness in the kraft bleaching process, it is known that metals, in particular transition metals naturally present in the pulp starting material, are detrimental to product brightness. Therefore, bleaching sequences are generally intended to remove certain transition metals from the final product to achieve the desired brightness. For example, a chelating agent can be used to remove naturally occurring metals from the pulp. Therefore, due to the emphasis on the removal of metals naturally present in the pulp, those skilled in the art typically do not add any metal to the bleaching sequence, which would therefore increase the difficulty of achieving a brighter product.

In the case of iron, in addition, the addition of this material to the pulp results in significant discoloration similar to the fading that occurs, for example, when burning paper. It is believed to date that this fading is irreversible like the fading of burning paper. Therefore, it is expected that after the iron wood pulp is fading, the pulp will permanently lose brightness, and the use of additional bleaching will not restore brightness.

Thus, although iron or copper and peroxide are known to oxidize cellulose inexpensively, they have not been used to date in a pulp bleaching process in a manner that achieves comparable brightness to a standard sequence that does not employ an iron or copper oxidation step. Generally, avoid using it in the pulp bleaching process. Surprisingly, the inventors have overcome these difficulties and, in some embodiments, have provided a novel method of inexpensively oxidizing cellulose using iron or copper in a pulp bleaching process. In some embodiments, the methods disclosed herein result in products that are extremely surprising and have opposite characteristics to those predicted based on the teachings of the prior art. Thus, the methods of the present disclosure can provide products that are superior to prior art products and that can be produced more cost effectively.

For example, it is generally understood in the art that metals such as iron are sufficiently bound to cellulose and cannot be removed by normal washing. In general, it is difficult to remove iron from cellulose and is relatively expensive and requires additional processing steps. It is known that the presence of high levels of residual iron in cellulosic products can have several disadvantages, especially in pulp and papermaking applications. For example, iron can cause fading of the final product and/or can be unsuitable for applications where the final product is in contact with the skin (eg, diapers and wound dressings). Therefore, the use of iron in the kraft bleaching process is expected to have a number of disadvantages.

To date, kraft fiber oxidative treatment to improve functionality has generally been limited to oxidative treatment after bleaching the fibers. In addition, known processes for imparting greater aldehyde functionality to the fibers also result in simultaneous loss of fiber brightness or quality. In addition, known processes for enhancing the aldehyde functionality of the fibers also result in a loss of carboxylic acid functionality. The method of the present disclosure does not create one or more of its disadvantages.

Kraft fiber produced by the chemical kraft pulping process provides a cheap source of cellulosic fibers (typically maintaining fiber length via pulping) and generally provides a final product with good brightness and strength characteristics. Therefore, it is widely used in paper applications. However, standard cowhide Paper fibers have limited applicability in downstream applications, such as the production of cellulose derivatives, resulting from the chemical structure of cellulose derived from standard kraft pulping and bleaching. In general, standard kraft fiber contains too much residual hemicellulose and other naturally occurring materials that can interfere with subsequent physical and/or chemical modification of the fiber. In addition, standard kraft fiber has limited chemical functionality and is generally rigid and not highly compressible.

The rigid and rough nature of kraft fiber may require delamination or the addition of different types of materials (such as cotton) to applications that require contact with human skin, such as diapers, hygiene products, and paper towels. Accordingly, it may be desirable to provide cellulosic fibers having better flexibility and/or flexibility to reduce the need to use other materials, such as in multilayer products.

Cellulose fibers in applications involving absorption of body waste and/or body fluids (eg, diapers, adult incontinence products, wound dressings, sanitary napkins, and/or cotton balls) are typically exposed to ammonia present in body waste and/or by the body Ammonia produced by bacteria associated with waste and/or body fluids. In such applications it might be desirable to use cellulose fibers as follows: it provides not only the volume of the absorbent and, Qieyi having reduced odor and / or anti-bacterial properties (e.g. from a nitrogen-containing compound can be reduced (e.g., ammonia (NH ₃₎₎ The smell). To date, modifying kraft fiber by oxidation to improve its odour control ability has undesirably reduced brightness. There is a need for inexpensive modified kraft fibers that exhibit good absorbency characteristics and/or odour control while maintaining good brightness characteristics.

In the current market, consumers expect thinner absorbent products such as diapers, adult incontinence products and sanitary napkins. Ultra-thin product designs require lower fiber weight and can result in loss of product integrity (if the fibers used are too short). Chemical modification of kraft fiber can result in loss of fiber length, making it unacceptable for use in certain types of products, such as ultra-thin products. More specifically, kraft fiber treated to improve aldehyde functionality, which is associated with improved odor control, can lose fiber length during chemical modification, making it unsuitable for ultra-thin product designs. It is desirable to exhibit compressibility without losing fiber length to make it uniquely suitable for ultra-thin design of inexpensive fibers (ie, based on the amount of fiber that can be compressed into a smaller space while maintaining product integrity at lower fiber weights) A product that is well absorbed).

Traditionally, the source of cellulose that can be used to produce absorbent products or paper towels cannot be used to produce downstream cellulose derivatives, such as cellulose ethers and cellulose esters. The production of low viscosity cellulose derivatives from high viscosity cellulosic raw materials, such as standard kraft fiber, requires additional manufacturing steps which add significant cost while imparting undesirable by-products and reducing the overall quality of the cellulose derivative. Lint and high alpha cellulose content sulfite pulp, which typically has a high degree of polymerization, are commonly used in the manufacture of cellulose derivatives such as cellulose ethers and esters. However, the production of lint and sulfite fibers with high degrees of polymerization and/or viscosity is relatively expensive due to the cost of starting materials (in the case of cotton), high energy in pulping and bleaching, chemical and environmental costs. (in the case of sulphite pulp) and the extensive purification process required (where applicable). In addition to high costs, the supply of sulphite pulp available for the market has decreased. Thus, such fibers are extremely expensive and have limited applicability in pulp and paper applications, for example, where higher DP or higher viscosity pulp may be required. For cellulose derivative manufacturers, these pulps constitute the bulk of their overall manufacturing cost. Therefore, there is a need for low cost fibers that can be used to produce cellulose derivatives, such as modified kraft fibers.

There is also a need for inexpensive cellulosic materials that can be used to make microcrystalline cellulose. Microcrystalline cellulose is widely used in food, pharmaceutical, cosmetic, and industrial applications, and is a partially purified form of depolymerized cellulose. To date, the use of kraft fiber in the production of microcrystalline cellulose has been limited without increasing the extensive bleaching post-treatment steps. Microcrystalline cellulose produces a cellulose starting material that typically requires high purification, which is acid hydrolyzed to remove amorphous segments of the cellulose chain. No. 5,346,589 to Braunstein et al. The low degree of polymerization (referred to as "stable DP") of the chain after removal of the amorphous section of cellulose is generally used as a starting point for the production of microcrystalline cellulose and its value is primarily dependent on the source and processing of the cellulose fibers. Dissolution of the amorphous section from standard kraft fiber typically degrades the fiber to such an extent that it is unsuitable for most applications, due to at least one of the following reasons: 1) residual impurities; 2) lack of sufficient length Crystallization Section; or 3) it yields cellulosic fibers having an excessive degree of polymerization (typically in the range of 200 to 400), making them useful for producing microcrystalline cellulose. For example, kraft fiber having good purity and/or lower stable DP value is desirable because the drawn fiber can provide greater versatility in microcrystalline cellulose production and application.

In the present disclosure, fibers having one or more of the properties set forth can be produced simply by modifying a typical kraft pulping and bleaching process. The fibers of the present disclosure overcome many of the limitations associated with the known modified kraft fibers described above.

Figure 1 shows a graph of the final 0.5% capillary CED viscosity as a function of the percentage of peroxide consumed.

Figure 2 shows a graph of wet strength to dry strength ratio as a function of wet strength resin content.

I. Method

The present disclosure provides a novel method of treating cellulosic fibers. In some embodiments, the present disclosure provides a method of modifying cellulosic fibers comprising providing cellulosic fibers and oxidizing the cellulosic fibers. As used herein, "oxidized and oxidized", "catalytically oxidized" (catalytic oxidation) are understood to be used interchangeably and refer to the use of at least one of at least one catalytic amount of iron or copper. The cellulose fibers are treated with at least one peroxide (e.g., hydrogen peroxide) such that at least some of the hydroxyl groups of the cellulose fibers are oxidized. The phrase "iron or copper" and similarly "iron (or copper)" means "iron or copper or a combination thereof". In some embodiments, the oxidizing comprises simultaneously increasing the carboxylic acid and aldehyde content of the cellulosic fibers.

The cellulosic fibers used in the methods described herein can be derived from softwood fibers, hardwood fibers, and mixtures thereof. In some embodiments, the modified cellulosic fiber system is derived from softwood, such as southern pine. In some embodiments, the modified cellulosic fiber system is derived from a hard Wood, such as eucalyptus. In some embodiments, the modified cellulosic fiber is derived from a mixture of softwood and hardwood. In yet another embodiment, the modified cellulosic fiber is derived from cellulosic fibers that have previously been subjected to all or a portion of the kraft process, i.e., kraft fiber.

"Cellulose fibers" or "kraft fibers" as referred to in this disclosure are used interchangeably unless they are specifically indicated to be different or familiar to those skilled in the art.

In at least one embodiment, the method includes providing cellulosic fibers and oxidizing the cellulosic fibers while generally maintaining the fiber length of the cellulosic fibers.

When used to describe fiber properties, "fiber length" and "average fiber length" are used interchangeably and refer to length-weighted average fiber length. Thus, for example, a fiber having an average fiber length of 2 mm is understood to mean a fiber having a length-weighted average fiber length of 2 mm.

In at least one embodiment, the method includes providing cellulosic fibers, partially bleaching the cellulosic fibers, and oxidizing the cellulosic fibers. In some embodiments, the oxidation is carried out in a bleaching process. In some embodiments, the oxidation is performed after the bleaching process.

In at least one embodiment, the method includes providing cellulosic fibers and oxidizing the cellulosic fibers, thereby reducing the degree of polymerization of the cellulosic fibers.

In at least one embodiment, the method includes providing cellulosic fibers and oxidizing the cellulosic fibers while maintaining a Canadian standard freeness ("freeness") of the cellulosic fibers.

In at least one embodiment, the method includes providing cellulosic fibers, oxidizing the cellulosic fibers, and increasing the brightness of the oxidized cellulosic fibers compared to standard cellulosic fibers.

As discussed above, in accordance with the present disclosure, oxidation of cellulosic fibers involves treating the cellulosic fibers with at least a catalytic amount of iron or copper and hydrogen peroxide. In at least one embodiment, the method includes oxidizing the cellulosic fibers using iron and hydrogen peroxide. The source of iron can be any suitable source as recognized by those skilled in the art, such as ferrous sulfate (e.g., ferrous sulfate heptahydrate), ferrous chloride, ammonium ferrous sulfate, ferric chloride, ferric ammonium sulfate. Or citric acid Iron ammonium.

In some embodiments, the method includes oxidizing the cellulosic fibers using copper and hydrogen peroxide. Similarly, the copper source can be any suitable source recognized by those skilled in the art. Finally, in some embodiments, the method includes oxidizing the cellulose fibers using copper and a combination of iron and hydrogen peroxide.

In some embodiments, the present disclosure provides a method of treating cellulosic fibers comprising providing cellulosic fibers, pulping cellulosic fibers, bleaching cellulosic fibers, and oxidizing cellulosic fibers.

In some embodiments, the method further comprises applying oxygen delignification to the cellulosic fibers. Oxygen delignification can be carried out by any of the methods known to those skilled in the art. For example, oxygen delignification can be a conventional two-stage oxygen delignification. For example, oxygen delignification of cellulosic fibers (e.g., kraft fiber) is known to alter the carboxylic acid and/or aldehyde content of the cellulosic fibers during processing. In some embodiments, the method comprises applying oxygen delignification to the cellulosic fibers prior to bleaching the cellulosic fibers.

In at least one embodiment, the method comprises oxidizing the cellulosic fibers in at least one of a kraft pulping step, an oxygen delignification step, and a kraft bleaching step. In a preferred embodiment, the method comprises oxidizing the cellulosic fibers in at least one kraft bleaching step. In at least one embodiment, the method comprises oxidizing the cellulosic fibers in two or more kraft bleaching steps.

When the cellulosic fibers are oxidized during the bleaching step, the cellulosic fibers should not undergo substantial alkaline conditions during or after oxidation during the bleaching process. In some embodiments, the method comprises oxidizing the cellulosic fibers at an acidic pH. In some embodiments, the method includes providing cellulosic fibers, acidifying the cellulosic fibers, and then oxidizing the cellulosic fibers at an acidic pH. In some embodiments, the pH is between about 2 to about 6, such as from about 2 to about 5 or from about 2 to about 4.

Any suitable acid (such as sulfuric acid or hydrochloric acid) recognized by those skilled in the art can be used. The filtrate is adjusted from the acid bleaching stage of the bleaching process (for example, the chlorine dioxide (D) stage of the multi-stage bleaching process). For example, cellulose fibers can be acidified by the addition of a foreign acid. Examples of foreign acids are known in the art and include, but are not limited to, sulfuric acid, hydrochloric acid, and carbonic acid. In some embodiments, the acidic filtrate (eg, waste filtrate) from the bleaching step is used to acidify the cellulose fibers. In some embodiments, the acidic filtrate from the bleaching step does not have a high iron content. In at least one embodiment, the acid filtrate acidified cellulose fibers from the D stage of the multi-stage bleaching process are used.

In some embodiments, the method comprises oxidizing the cellulosic fibers in one or more stages of the multi-stage bleaching sequence. In some embodiments, the method comprises oxidizing the cellulosic fibers in a single stage of the multi-stage bleaching sequence. In some embodiments, the method comprises oxidizing the cellulosic fibers at or near the end of the multi-stage bleaching sequence. In some embodiments, the method comprises oxidizing the cellulosic fibers in at least stage 4 of the 5-stage bleaching sequence.

According to the present disclosure, the multi-stage bleaching sequence can be any bleaching sequence that does not include an alkaline bleaching step after the oxidation step. In at least one embodiment, the multi-stage bleaching sequence is a 5-stage bleaching sequence. In some embodiments, the bleaching sequence is a DEEDED sequence. In some embodiments, the bleaching sequence D ₀ E1D1E2D2 sequence. In some embodiments, the bleaching sequence is a _D0 (EoP)D1E2D2 sequence. In some embodiments, the bleaching sequence is D ₀ (EO) D1E2D2.

The non-oxidative stage of the multi-stage bleaching sequence can comprise any of the conventional stages or can be carried out under conventional conditions after the series of stages found, provided that there is no alkaline bleaching step after the oxidation step to be useful for producing the disclosures set forth in this disclosure. Modified fiber.

In some embodiments, the oxidation is incorporated into the fourth stage of the multi-stage bleaching process. In some embodiments, the process is carried out in a 5-stage bleaching process with the sequence D ₀ E1D1E2D2 and the 4th stage (E2) is used to oxidize the kraft fiber.

In some embodiments, the kappa number (kappa) after oxidation of the cellulose fibers Number) has increased. More specifically, based on the expected reduction in the material (e.g., lignin) that reacts with the permanganate reagent, it is generally expected that the Kappa number will decrease during this bleaching stage. However, in the methods as set forth herein, the Kappa number of the cellulose fibers can be reduced by loss of impurities such as lignin; however, the Kappa number can be increased by chemical modification of the fibers. Without wishing to be bound by theory, it is believed that increasing the functionality of the modified cellulose provides an additional site that can react with the permanganate reagent. Therefore, the Kappa number of the modified kraft fiber is increased relative to the Kappa number of the standard kraft fiber.

In at least one embodiment, the oxidation occurs in a single stage of the bleaching sequence after the addition of iron or copper and peroxide and providing some residence time. Proper retention of iron or copper is sufficient to catalyze the amount of hydrogen peroxide for a period of time. This time can be readily determined by those skilled in the art.

According to the present disclosure, oxidation is carried out for a certain period of time at a temperature sufficient to desirably complete the reaction. For example, the oxidation can be carried out at a temperature between about 60 ° C to about 80 ° C and a time between about 40 minutes and about 80 minutes can be implemented. The desired time and temperature of the oxidation reaction can be readily determined by those skilled in the art.

Advantageously, the cellulosic fibers are digested to a target Kappa number prior to bleaching. For example, when the paper grade pulp or cellulose fluff desired oxidized cellulose, cellulose fibers can be digested to a kappa use Lo-Solids ^TM two vessel hydraulic digester to digester prior to oxidation and bleaching cellulose The value is between about 30 and about 32. Alternatively, if oxidized cellulose is desired in cellulose derivative applications (e.g., in the manufacture of cellulose ethers), the cellulose fibers can be digested to the card prior to bleaching and oxidizing the cellulose in accordance with the methods of the present disclosure. The berth is between about 20 and about 24. In some embodiments, the cellulosic fibers are digested and the lignin is removed during the conventional two-stage oxygen delignification step prior to bleaching and oxidizing the cellulosic fibers. Advantageously, the delignification is carried out until the target Kappa number is between about 6 and about 8 (when the oxidized cellulose is intended for use in a cellulose derivative application) and the target Kappa number is between about 12 and about 14 Between (when oxidized cellulose is intended for paper and/or fluff applications).

In some embodiments, the bleaching process is carried out under conditions to achieve about 88- 90% of the final target ISO brightness, for example between about 85% to about 95% or between about 88% and about 90%.

The present disclosure also provides a method of treating cellulosic fibers comprising providing cellulosic fibers, reducing the DP of the cellulosic fibers, and maintaining the fiber length of the cellulosic fibers. In some embodiments, the cellulosic fibers are kraft fiber. In some embodiments, the DP of the cellulosic fibers is reduced during the bleaching process. In some embodiments, the DP of the cellulosic fibers is reduced at or near the end of the multi-stage bleaching sequence. In some embodiments, the DP is reduced at least in the fourth stage of the multi-stage bleaching sequence. In some embodiments, the DP is reduced during or after the fourth stage of the multi-stage bleaching sequence.

Alternatively, the multi-stage bleaching sequence can be altered to provide more stable bleaching conditions prior to oxidation of the cellulosic fibers. In some embodiments, the method includes providing more stable bleaching conditions prior to the oxidizing step. More stable bleaching conditions can be used to reduce the degree of polymerization and/or viscosity of the cellulosic fibers by using lesser amounts of iron or copper and/or hydrogen peroxide in the oxidation step. Thus, the bleaching sequence conditions can be modified to further control the brightness and/or viscosity of the final cellulosic product. For example, reducing the amount of peroxide and metal while providing more stable bleaching conditions prior to oxidation provides products with lower viscosity and higher brightness than oxidized products that use the same oxidation conditions but use less stable bleaching. . In some embodiments, such conditions may be particularly advantageous for cellulose ether applications.

In some embodiments, the method of the present disclosure further includes reducing the crystallinity of the cellulosic fibers such that they are less than the crystallinity of the cellulosic fibers measured prior to the oxidation stage. For example, according to the method of the present disclosure, the crystallinity index of the cellulose fibers can be reduced by up to 20% relative to the initial crystallinity index measured before the oxidation stage.

In some embodiments, the methods of the present disclosure further comprise treating the modified cellulosic fibers with at least one caustic or alkaline material. For example, in at least one embodiment, a method of treating cellulosic fibers includes providing the oxidized cellulosic fibers of the present disclosure, exposing the oxidized cellulosic fibers to an alkaline or caustic material, and then producing the cellulosic material The product is dry. Without being bound by theory, it is believed that the addition of at least one caustic to the modified cellulose results in cellulosic fibers having very high functionality and very low fiber length.

It is known that cellulose comprising an increased aldehyde group may have the advantageous property of improving the wet strength of the cellulosic fiber. See, for example, U.S. Patent No. 6,319,361 to Smith et al., and to No. 6,582,559 to Thornton et al. These properties can be beneficial, for example, to absorbent material applications. In some embodiments, the present disclosure provides a method of improving the wet strength of a product comprising providing a modified cellulosic fiber of the present disclosure and adding a modified cellulosic fiber of the present disclosure to a product, such as a paper product. For example, the method can include oxidizing the cellulosic fibers in a bleaching process, further treating the oxidized cellulosic fibers with an acidic or caustic material, and adding the treated fibers to the cellulosic product.

In accordance with the present disclosure, hydrogen peroxide is added to the cellulosic fibers present in the acidic medium in an amount sufficient to achieve the desired oxidation and/or degree of polymerization and/or viscosity of the final cellulosic product. For example, the 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%, based on the dry weight of the pulp.

Iron or copper is added at least in an amount sufficient to catalyze the oxidation of the cellulose with the peroxide. For example, iron may be added in an amount between about 25 ppm to about 200 ppm based on the dry weight of the kraft pulp. Those skilled in the art will be able to readily optimize the amount of iron or copper to achieve the desired degree or amount of oxidation and/or degree of polymerization and/or viscosity of the final cellulosic product.

In some embodiments, the method additionally involves adding steam before or after the addition of hydrogen peroxide.

In some embodiments, the final DP and/or viscosity of the pulp can be controlled by the amount of iron or copper and hydrogen peroxide and the stability of the bleaching conditions prior to the oxidation step. Those skilled in the art will recognize that other properties of the modified kraft fiber of the present disclosure may be affected by the amount of iron or copper and hydrogen peroxide and the stability of the bleaching conditions prior to the oxidation step. For example, those skilled in the art can adjust the amount of iron or copper and hydrogen peroxide and the stability of the bleaching conditions prior to the oxidation step to target or achieve the desired brightness and/or desired degree of polymerization or viscosity of the final product. degree.

In some embodiments, the present disclosure provides a method of modifying cellulosic fibers comprising providing cellulosic fibers, reducing the degree of polymerization of the cellulosic fibers, and maintaining the fiber length of the cellulosic fibers.

In some embodiments, the oxidized kraft fiber of the present disclosure is not refined. Refined oxidized kraft fiber can have a negative impact on fiber length and integrity, for example, finishing fibers can cause fiber splitting.

In some embodiments, each stage of the 5-stage bleaching process comprises at least a mixer, a reactor, and a scrubber (as known to those skilled in the art).

In some embodiments, the kraft pulp is acidified on a D1 stage scrubber, and the iron source is also added to the kraft pulp on a D1 stage scrubber, after the iron source (or copper source) before the E2 stage tower mixer or pump The peroxide is added at the point of addition, the kraft pulp is reacted in an E2 column and washed on an E2 scrubber, and steam may optionally be added to the steam mixer prior to the E2 column.

In some embodiments, iron (or copper) may be added until the end of the D1 phase, or iron (or copper) may be added at the beginning of the E2 phase, provided that first (ie before adding iron) in the D1 phase Acidified pulp. Steam may be added before or after the peroxide is added as appropriate.

In an exemplary embodiment, a method of making a low viscosity modified cellulosic fiber can involve bleaching kraft pulp in a multi-stage bleaching process and in the final stage of the multi-stage bleaching process or near the final stage (eg, in a multi-stage bleaching process) In the fourth stage, for example, in the fourth stage of the 5-stage bleaching process, the pulp DP is reduced by treatment with hydrogen peroxide in an acidic medium and in the presence of iron. For example, the final DP of the pulp can be controlled by the appropriate application of iron or copper and hydrogen peroxide, as further illustrated in the Examples section. In some embodiments, the fibers are adapted to produce low DP fibers (i.e., fibers having a DPw between about 1180 and about 1830 or a 0.5% capillary CED viscosity of between about 7 mPa ‧ and about 13 mPa ‧ s) Amount and conditions to provide iron or copper and hydrogen peroxide. In some exemplary embodiments, it may be suitable to produce ultra-low DP fibers (ie, a DPw of between about 700 and about 1180 or a 0.5% capillary CED viscosity of between about 3.0 mPa ‧ and about 7 mPa ‧ s) The amount and condition of the fiber) provides iron or copper and hydrogen peroxide.

For example, in some embodiments, treatment with hydrogen peroxide and iron or copper in an acidic medium can involve adjusting the pH of the kraft pulp to a pH between about 2 and about 5, adding to the acidified pulp. Iron source and hydrogen peroxide is added to the kraft pulp.

In some embodiments, for example, a method of making modified cellulose fibers within the scope of the present disclosure may involve acidifying kraft pulp to a pH between about 2 and about 5 (eg, using sulfuric acid), a source of mixed iron (eg ferrous sulfate, such as ferrous sulfate heptahydrate) and acidified kraft pulp (from about 25 ppm to about 250 ppm Fe ⁺² (based on dry weight of kraft pulp, between about 1% to about 15%) Under consistency) also hydrogen peroxide (which may be in the form of a solution having a concentration of from about 1% by weight to about 50% by weight and added in an amount of between about 0.1% and about 1.5% based on the dry weight of the kraft pulp) . In some embodiments, the ferrous sulfate solution is mixed with kraft pulp at a consistency of between about 7% and about 15%. In some embodiments, the acid kraft pulp is mixed with an iron source and reacted with hydrogen peroxide at a temperature between about 60 ° C to about 80 ° C for a period of time between about 40 minutes and about 80 minutes.

In some embodiments, a method of making modified cellulose fibers within the scope of the present disclosure involves reducing DP by treating the kraft pulp in the presence of iron (or copper) in an acidic medium using hydrogen peroxide, wherein the acid is Hydrogen peroxide and iron (or copper) treatment are included in the multi-stage bleaching process. In some embodiments, the treatment of iron, acid, and hydrogen peroxide is included in a single stage of a multi-stage bleaching process. In some embodiments, the treatment of iron (or copper), acid, and hydrogen peroxide is included in a single stage at or near the end of the multi-stage bleaching process. In some embodiments, iron (or copper), acid, and hydrogen peroxide treatment are included in stage 4 of the multi-stage bleaching process. For example, adding iron (or copper) and peroxide and providing some hysteresis After the residence time, pulp processing can occur in a single stage (eg, the E2 stage). In some embodiments, each stage of the 5-stage bleaching process comprises at least a mixer, a reactor, and a scrubber (as known to those skilled in the art), and the kraft pulp can be acidified on a D1 stage scrubber. An iron source is also added to the kraft pulp on the D1 stage scrubber, which can be added at the point of addition of the E2 stage tower before the E2 stage tower or in the pump after the source of iron (or copper source), in the E2 column The kraft pulp is reacted and washed on an E2 scrubber, and steam may optionally be added to the steam mixer prior to the E2 column. In some embodiments, for example, iron (or copper) may be added until the end of the D1 phase, or iron (or copper) may be added at the beginning of the E2 phase, provided that first (ie, prior to the addition of iron) The pulp is acidified in a stage, additional acid may be added as needed to bring the pH to a range of from about 3 to about 5, and the peroxide may be added after the iron (or copper). Steam can be added before or after the peroxide is added.

For example, in one embodiment, the above-described 5-stage bleaching process performed using a softwood cellulose starting material can produce modified cellulose fibers having one or more of the following properties: an average fiber length of at least 2.2 mm, The viscosity is between about 3.0 mPa‧s and less than 13 mPa‧s, the S10 caustic solubility is between about 16% and about 20%, the S18 caustic solubility is between about 14% and about 18%, and the carboxyl content is between Between 2 meq/100 g and about 6 meq/100 g, the aldehyde content is between about 1 meq/100 g to about 3 meq/100 g, the carbonyl content is about 1 to 4, and the freeness is between about 700 mls to about 760 mls, fiber strength. It is between about 5 km and about 8 km and has a brightness between about 85 ISO and about 95 ISO. For example, in some embodiments, the above exemplary 5-stage bleaching process can produce modified cellulose softwood fibers having each of the above properties.

According to another example, wherein the cellulosic fiber is a softwood fiber, the above exemplary 5-stage bleaching process produces a modified cellulosic softwood fiber having an average fiber length of at least 2.0 mm (eg, between about 2.0 mm and about Between 3.7 mm or about 2.2 mm to about 3.7 mm), the viscosity is less than 13 mPa ‧ (for example, the viscosity is between about 3.0 mPa ‧ s to less than 13 mPa ‧ s or about 3.0 mPa ‧ s to about 5.5 mPa ‧ s or about 3.0 mPa ‧s to about 7mPa‧s or about 7 mPa‧s to less than 13 rrPa s) and brightness of at least 85 (eg, between about 85 and about 95).

In some embodiments, the present disclosure provides a method of producing fluff pulp comprising providing a modified kraft fiber of the present disclosure and then producing fluff pulp. For example, the method comprises bleaching the kraft fiber in a multi-stage bleaching process, at least in the fourth or fifth stage of the multi-stage bleaching process, using hydrogen peroxide to oxidize the fiber under acidic conditions and a catalytic amount of iron or copper, And then fluff pulp is formed. In at least one embodiment, the fibers are not refined after the multi-stage bleaching process.

The present disclosure also provides methods of reducing odor (eg, from odors of body waste, such as odors from urine or blood). In some embodiments, the present disclosure provides a method of controlling odor comprising providing a modified bleached kraft fiber of the present disclosure, and applying an odorant to the bleached kraft fiber to a standard kraft fiber of equivalent weight The atmospheric amount of the odorant is reduced as compared to the atmospheric amount of the odorant after the equivalent amount of odorant is applied. In some embodiments, the present disclosure provides a method of controlling odor comprising inhibiting bacterial odor generation. In some embodiments, the present disclosure provides a method of controlling odor comprising absorbing an odorant (eg, a nitrogen-containing scent) onto a modified kraft fiber. As used herein, "nitrogen-containing scent" is understood to mean an odorant comprising at least one nitrogen.

In at least one embodiment, a method of reducing odor comprises providing a modified cellulosic fiber of the present disclosure, and applying an odorant (eg, a nitrogen-containing compound (eg, ammonia) or capable of forming a nitrogen-containing compound to the modified kraft fiber. organism). In some embodiments, the method further comprises forming the fluff pulp from the modified cellulosic fibers prior to adding the odorant to the modified kraft fiber. In some embodiments, the odorant comprises at least one bacterium capable of producing a nitrogen-containing compound. In some embodiments, the odorant comprises a nitrogen containing compound, such as ammonia.

In some embodiments, the method of reducing odor further comprises absorbing ammonia into the repaired Decorated with cellulose fibers. In some embodiments, the method of reducing odor further comprises inhibiting bacterial ammonia production. In some embodiments, a method of inhibiting bacterial ammonia production comprises inhibiting bacterial growth. In some embodiments, a method of inhibiting bacterial ammonia production comprises inhibiting bacterial urea synthesis.

In some embodiments, the method of reducing odor comprises combining the modified cellulosic fibers with at least one other deodorant, and then applying an odorant to the modified cellulosic fibers in combination with the deodorant.

Exemplary deodorants are known in the art and include, for example, odor reducing agents, odor masking agents, biocides, enzymes, and urease inhibitors. For example, the modified cellulosic fiber can be combined with at least one deodorant selected from the group consisting of zeolite, activated carbon, diatomaceous earth, cyclodextrin, clay, chelating agents (eg, such as copper ions, silver, etc.) A metal ion such as an ion or a zinc ion), an ion exchange resin, an antibacterial or antimicrobial polymer, and/or a fragrance.

In some embodiments, the modified cellulosic fibers are combined with at least one superabsorbent polymer (SAP). In some embodiments, the SAP can be an odorant. Examples of SAPs that may be used in the present disclosure include, but are not limited to, Hysorb ^(TM) sold by BASF Corporation, Aqua Keep® sold by Sumitomo Corporation, and FAVOR® sold by Evonik Corporation.

II. Kraft fiber

This article refers to "standard", "custom" or "traditional" kraft fiber, kraft bleached fiber, kraft pulp or kraft bleached pulp. The fiber or pulp is generally described as a reference point defining the improved properties of the present invention. As used herein, the terms are used interchangeably and refer to the same composition as the target fiber or pulp that has not been subjected to any oxidation (either alone or subsequently with one or more bases or acids) and treated in a similar manner (ie, Fiber or pulp treated in a standard or customary manner). As used herein, the term "modification" means that the fiber is subjected to an oxidation treatment (either alone or subsequently with one or more base or acid treatments).

The physical properties (e.g., fiber length and viscosity) of the modified cellulosic fibers referred to in the specification are measured according to the protocol provided in the Examples section.

The present disclosure provides kraft fiber having a low and ultra low viscosity. As used herein, "viscosity" means a 0.5% capillary CED viscosity as measured by TAPPI T230-om99 as referred to in the scheme. The modified kraft fiber of the present invention exhibits unique characteristics indicative of its chemical modification. More specifically, the fibers of the present invention exhibit properties similar to those of standard kraft fiber (i.e., length and freeness), but also exhibit some variation as the number of functional groups contained in the modified fiber increases. Different characteristics. This modified fiber exhibits unique properties when implemented in the reference TAPPI test for measuring viscosity. In particular, the referenced TAPPI test uses a caustic reagent to treat the fiber as part of the test method. As illustrated, the application of a caustic agent to the modified fibers causes the modified fibers to hydrolyze in a manner different from standard kraft fibers, thereby reporting a viscosity that is generally lower than the viscosity of standard kraft fibers. Therefore, those skilled in the art should understand that the reported viscosity can be affected by the viscosity measurement method. For the purposes of the present invention, the viscosity reported herein (as measured by the referenced TAPPI method) represents the viscosity of the kraft fiber used to calculate the degree of fiber polymerization.

As used herein, "DP" refers to the average weight polymerization (DPw) calculated from a 0.5% capillary CED viscosity measured according to TAPPI T230-om99, unless otherwise specified. See, for example JFCellucon Conference, The Chemistry and Processing of Wood and Plant Fibrous Materials, pp. 155, test program 8,1994 (Woodhead Publishing Ltd., Abington Hall, Abinton Cambridge CBI 6AH England, JFKennedy et al. Eds). By "low DP" is meant a DP between about 1160 and about 1860 or a viscosity between about 7 mPa ‧ s to about 13 mPa ‧ s. By "ultra-low DP" fiber is meant a DP between about 350 and about 1160 or a viscosity between about 3 mPa ‧ s to about 7 mPa ‧ s.

Without wishing to be bound by theory, it is believed that the fibers of the invention exhibit an artificial degree of polymerization when the DP is calculated via the CED viscosity measured according to TAPPI T230-om99. In particular, it is believed that catalytic oxidation of the fibers of the present invention does not decompose cellulose to be indicated by the measured DP To the extent that it primarily has the effect of opening the bond and adding a substituent to make the cellulose more reactive, rather than cracking the cellulose chain. It is also believed that the CED viscosity test (TAPPI T230-om99, which begins with the addition of caustic reagents) has the effect of cracking the cellulose chain at the new reactive site, resulting in a much higher than found in the pre-fiber test state. A shorter number of cellulosic polymers. This can be confirmed by the fact that the fiber length does not decrease significantly during production.

In some embodiments, the modified cellulosic fibers have a DP of between about 350 and about 1860. In some embodiments, the DP is between about 710 and about 1860. In some embodiments, the DP is between about 350 and about 910. In some embodiments, the DP is between about 350 and about 1160. In some embodiments, the DP is between about 1160 and about 1860. In some embodiments, the DP is less than 1860, less than 1550, less than 1300, less than 820, or less than 600.

In some embodiments, the modified cellulosic fibers have a viscosity of between about 3.0 mPa ‧ s to about 13 mPa ‧ s. In some embodiments, the viscosity is between about 4.5 mPa ‧ s to about 13 mPa ‧ s. In some embodiments, the viscosity is between about 3.0 mPa ‧ s to about 5.5 mPa ‧ s. In some embodiments, the viscosity is between about 3.0 mPa ‧ s to about 7 mPa ‧ s. In some embodiments, the viscosity is between 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.

In some embodiments, the modified kraft fiber of the present disclosure maintains its freeness during the bleaching process. In some embodiments, the modified cellulosic fibers have a "freeness" of at least about 690 mls (eg, at least about 700 mls or about 710 mls or about 720 mls or about 730 mls).

In some embodiments, the modified kraft fiber of the present disclosure maintains its fiber length during the bleaching process.

In some embodiments, the modified cellulose fiber softwood fiber is modified The cellulosic fibers have an average fiber length of about 2 mm or greater as measured according to Test Protocol 12 set forth in the Examples section below. In some embodiments, the average fiber length is no greater 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, about 2.8 mm, about 2.9 mm, about 3.0 mm, about 3.1 mm. , about 3.2 mm, about 3.3 mm, about 3.4 mm, about 3.5 mm, about 3.6 mm, or about 3.7 mm. In some embodiments, the average fiber length is between about 2 mm to about 3.7 mm or between about 2.2 mm to about 3.7 mm.

In some embodiments, the modified cellulosic fibers have an average fiber length of from about 0.75 mm to about 1.25 mm when the modified cellulosic fiber-based hardwood fibers are modified. For example, the average fiber length can be at least about 0.85 mm, such as about 0.95 mm or about 1.05 mm or about 1.15 mm.

In some embodiments, the modified kraft fiber of the present disclosure has a brightness equivalent to that of a standard kraft fiber. In some embodiments, the modified cellulosic fibers have a brightness of at least 85, 86, 87, 88, 89, or 90 ISO. In some embodiments, the brightness is no greater than about 92. In some embodiments, the brightness is between 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.

In some embodiments, the modified cellulosic fibers of the present disclosure are more compressible and/or embossable than standard kraft fibers. In some embodiments, the modified cellulosic fibers can be used to produce structures having a thinner and/or higher density than structures produced using equivalent amounts of standard kraft fiber.

In some embodiments, the modified cellulosic fibers of the present disclosure can be compressed to a density of at least about 0.21 g/cc, such as about 0.22 g/cc or about 0.23 g/cc or about 0.24 g/cc. In some embodiments, the modified cellulosic fibers of the present disclosure can be compressed to a density of between about 0.21 g/cc to about 0.24 g/cc. In at least one embodiment, the modified cellulosic fibers of the present disclosure have a density of between about 0.21 g/cc to about 0.24 g/cc after compression at 20 psi gauge.

In some embodiments, the modified cellulosic fibers of the present disclosure have a density of between about 0.110 g/cc to about 0.114 g/cc after compression at about 5 psi gauge. For example, the modified cellulosic fibers of the present disclosure can have at least about 0.110 g/cc (eg, at least about 0.112 g/cc or about 0.113 g/cc or about 0.114 g/cc after compression at about 5 psi gauge). The density of).

In some embodiments, the modified cellulosic fibers of the present disclosure have a density of between about 0.130 g/cc to about 0.155 g/cc after compression at about 10 psi gauge. For example, the modified cellulosic fibers of the present disclosure can have at least about 0.130 g/cc (e.g., at least about 0.135 g/cc or about 0.140 g/cc or about 0.145 g/cc after compression at about 10 psi gauge). Or a density of about 0.150 g/cc).

In some embodiments, the modified cellulosic fibers of the present disclosure can be compressed to a density that is at least about 8% higher than the density of standard kraft fibers. In some embodiments, the modified cellulosic fibers of the present disclosure have a density that is from about 8% to about 16% greater than the density of standard kraft fibers, such as 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%.

In some embodiments, the modified kraft fiber of the present disclosure has an increased carboxyl content relative to standard kraft fiber.

In some embodiments, the modified cellulosic fibers have a carboxyl content of between about 2 meq/100 g to about 9 meq/100 g. In some embodiments, the carboxyl group content is between 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 at least about 2 meq/100 g, such as at least about 2.5 meq/100 g, such as at least about 3.0 meq/100 g, such as at least about 3.5 meq/100 g, such as at least about 4.0 meq/100 g, such as at least about 4.5 meq/100 g, or for example at least about 5.0 meq/100 g.

The modified kraft fiber of the present disclosure has an increased aldehyde content relative to standard bleached kraft fiber. In some embodiments, the modified kraft fiber has a ratio of about 1 The aldehyde content between meq/100g to about 9meq/100g. In some embodiments, the aldehyde content is at least about 1.5 meq/100 g, about 2 meq/100 g, about 2.5 meq/100 g, about 3.0 meq/100 g, about 3.5 meq/100 g, about 4.0 meq/100 g, about 4.5 meq/100 g. Or about 5.0 meq/100 g or at least about 6.5 meq or at least about 7.0 meq.

In some embodiments, the modified cellulosic fibers have a ratio of total aldehyde to carboxyl content of greater than about 0.3 (eg, greater than about 0.5, such as greater than about 1, such as greater than about 1.4). In some embodiments, the aldehyde to base ratio is between about 0.3 and about 1.5. In some embodiments, the ratio is between about 0.3 and about 0.5. In some embodiments, the ratio is between about 0.5 and about 1. In some embodiments, the ratio is between about 1 and about 1.5.

In some embodiments, the modified kraft fiber has a kink and curl that is higher than standard kraft fibers. The modified kraft fiber of the present invention has a kink index in the range of from about 1.3 to about 2.3. For example, the kink index can be between 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 kraft fiber of the present disclosure can have a length weighted crimp index in the range of from about 0.11 to about 0.23 (e.g., from about 0.15 to about 0.2).

In some embodiments, the crystallinity index of the modified kraft fiber is reduced by from about 5% to about 20%, such as from about 10% to about 20% or from about 15% to about 20%, relative to the crystallinity index of the standard kraft fiber. .

In some embodiments, the modified cellulose of the present disclosure has an R10 value between about 65% to about 85% (eg, from about 70% to about 85% or from about 75% to about 85%). In some embodiments, the modified fibers of the present disclosure have an R18 value between about 75% to about 90% (eg, from about 80% to about 90%, such as from about 80% to about 87%). The R18 and R10 levels are set forth in TAPPI 235. R10 represents the residual undissolved material remaining after the pulp was extracted using 10% by weight of the caustic solution, and R18 represents the residual amount of the undissolved material remaining after the pulp was extracted using the 18% caustic solution. Typically, hemicellulose and chemically degraded short chain cellulose are dissolved in solution and removed in a 10% caustic solution. In comparison, usually only half fiber The compound is dissolved in 18% caustic solution and removed. Thus, the difference between the R10 value and the R18 value (R = R18 - R10) represents the amount of chemically degraded short chain cellulose present in the pulp sample.

Based on one or more of the above properties (e.g., kink knots and crimps, increased functionality, and crystallinity of the modified kraft fiber), those skilled in the art will appreciate that the modified kraft fiber of the present disclosure has standard kraft fiber. Some features are not owned. For example, it is believed that the kraft fiber of the present disclosure may be more flexible than standard kraft fiber and may be stretchable and/or curved and/or exhibit elasticity and/or increase wicking. In addition, without being bound by theory, it is contemplated that the modified kraft fiber can provide, for example, in the fluff pulp to entangle the fibers and bond the fibers/fibers or to wrap the material applied to the pulp (so that the materials remain in the pulp relative to each other) The physical structure at which the space is fixed to prevent it from being dispersed. In addition, it is expected that the modified kraft fiber of the present disclosure is softer than standard kraft fiber, at least because of the reduced crystallinity relative to standard kraft fiber, thereby enhancing its application in absorbent product applications such as diapers and bandage applications. Sex.

In some embodiments, the modified cellulosic fibers have an S10 caustic solubility of between about 16% to about 30% or between about 14% and about 16%. In some embodiments, the modified cellulosic fibers have an S18 caustic solubility of between about 14% to about 22% or between about 14% to about 16%. In some embodiments, the modified cellulosic fibers have a ΔR of about 2.9 or greater (the difference between S10 and S18). In some embodiments, ΔR is about 6.0 or greater.

In some embodiments, the modified cellulosic fiber strength (as measured by the wet zero break length) is between about 4 km and about 10 km (eg, between about 5 km and 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 between about 5 km and about 7 km or between about 6 km and about 7 km.

In some embodiments, the modified kraft fiber has odor control properties. In some embodiments, the modified kraft fiber can reduce the odor of body waste, such as urine or menses. In some embodiments, the modified kraft fiber absorbs ammonia. In some embodiments The modified kraft fiber inhibits bacterial odor generation, for example, in some embodiments, the modified kraft fiber inhibits bacterial ammonia production.

In at least one embodiment, the modified kraft fiber is capable of absorbing an odorant (eg, a nitrogen-containing odorant, such as ammonia).

As used herein, the term "odorant" is understood to mean a chemical material having a taste or odor or capable of interacting with an olfactory receptor, or an organism capable of producing a compound that produces a taste or odor (eg, a bacterium, eg, The bacteria that produce urea).

In some embodiments, the reduction in atmospheric ammonia over standard bleached kraft fiber, the modified kraft fiber reduces the greater atmospheric ammonia concentration. For example, the modified kraft fiber can reduce atmospheric ammonia by absorbing at least a portion of the ammonia sample applied to the modified kraft fiber or by inhibiting bacterial ammonia production. In at least one embodiment, the modified kraft fiber absorbs ammonia and inhibits bacterial ammonia production.

In some embodiments, the modified kraft fiber reduces at least about 40% of the atmospheric ammonia of the standard kraft fiber, such as at least about 50% or more than about 60% or more than about 70% or more than about 75% more than the standard kraft fiber. Or about 80% or more of about 90% ammonia.

In some embodiments, the modified kraft fiber of the present disclosure will have an atmospheric ammonia concentration in a volume of 1.6 L after applying 0.12 g of a 50% ammonium hydroxide solution to about 9 grams of modified cellulose and for a 45 minute incubation period. Reduced to less than 150 ppm (eg, less than about 125 ppm, such as less than about 100 ppm, such as less than about 75 ppm, such as less than about 50 ppm).

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

In some embodiments, the modified kraft fiber has improved odor control properties and improved brightness compared to standard kraft fiber. In at least one embodiment, the modified fiber The vitamin fibers have a brightness between about 85 and about 92 and are capable of reducing odor. For example, the modified cellulose can have a brightness between about 85 and about 92 and absorb about 5 ppm ammonia per gram of fiber to about 10 ppm ammonia per gram of fiber.

In some embodiments, the modified cellulosic fibers are less than 2 in the 0 to 4 scale in the MEM elution cytotoxicity test (ISO 10993-5). For example, the cytotoxicity can be less than about 1.5 or less than about 1.

It is known that cellulose oxidized, in particular cellulose comprising aldehydes and/or carboxylic acid groups, exhibits antiviral and/or antimicrobial activity. See, for example, Song et al., Novel antiviral activity of dialdehyde starch, Electronic J. Biotech., Vol. 12, No. 2, 2009; U.S. Patent No. 7,019,191 to Looney et al. For example, aldehyde groups in dialdehyde starch are known to provide antiviral activity, and oxidized cellulose and oxidized regenerated cellulose (eg, containing carboxylic acid groups) are typically used in wound care applications, this section The ground system has bactericidal and hemostatic properties. Thus, in some embodiments, the cellulosic fibers of the present disclosure may exhibit antiviral and/or antimicrobial activity. In at least one embodiment, the modified cellulosic fibers exhibit antibacterial activity. In some embodiments, the modified cellulosic fibers exhibit antiviral activity.

In some embodiments, the modified kraft fiber of the present disclosure has a stable DP of less than 200 (eg, less than about 100 or less than about 80 or less than about 75 or less than about 50 or less than or equal to about 48). Stable DP can be measured by methods known in the art, for example by revealing Battista et al., Level-Off Degree of Polymerization, Division of Cellulose Chemistry, Symposium on Degradation of Cellulose and Cellulose Derivatives, 127th meeting, ACS, Cincinnati , Ohio, the method from March to April 1955.

In some embodiments, the modified kraft fiber has a kappa number of less than about 2. For example, the modified kraft fiber can have a Kappa number of less than about 1.9. In some embodiments, the modified kraft fiber has a Kappa number between about 0.1 and about 1, such as about From 0.1 to about 0.9, such as from about 0.1 to about 0.8, such as from about 0.1 to about 0.7, such as from about 0.1 to about 0.6, such as from about 0.1 to about 0.5 or from about 0.2 to about 0.5.

In some embodiments, the modified kraft fiber is a kraft fiber that is bleached in a multi-stage process wherein at least one bleaching step is performed after the oxidizing step. In such embodiments, the modified fibers after at least one bleaching step have a "k value" between about 0.2 and about 1.2, as measured according to TAPPI UM 251. For example, the k value can be between 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 about 1.2.

In some embodiments, the modified cellulosic fibers have a copper value greater than about 2. In some embodiments, the copper value is greater than 2.0. In some embodiments, the copper value is greater than about 2.5. For example, the copper value can be greater than about 3. In some embodiments, the copper value is between about 2.5 and about 5.5, such as from about 3 to about 5.5, such as from about 3 to about 5.2.

In at least one embodiment, the modified kraft fiber has a hemicellulose content that is substantially the same as a standard unbleached kraft fiber. For example, the softwood kraft fiber may have a hemicellulose content of between about 16% and about 18%. For example, the hardwood kraft fiber may have a hemicellulose content of between about 18% and about 25%.

III. Further Treatment - Acid/Base Hydrolysis

In some embodiments, the modified kraft fiber of the present disclosure is suitable for producing a cellulose derivative, such as for producing a lower viscosity cellulose ether, a cellulose ester, and a microcrystalline cellulose. In some embodiments, the modified kraft fiber of the present disclosure is a modified kraft fiber that is hydrolyzed. As used herein, "hydrolyzed modified kraft fiber", "hydrolyzed kraft fiber" and the like are understood to mean a fiber which is hydrolyzed by treatment with any of the known acids or bases to depolymerize the cellulose chain. In some embodiments, the kraft fiber of the present disclosure is further processed to reduce its viscosity and/or degree of polymerization. For example, the kraft fiber of the present disclosure can be treated with an acid or a base.

In some embodiments, the present disclosure provides a method of treating kraft fiber comprising bleaching the kraft fiber of the present disclosure and then hydrolyzing the bleached kraft fiber. Hydrolysis can be carried out by any of the methods known to those skilled in the art. In some embodiments, at least one acid hydrolyzed bleached kraft fiber is used. In some embodiments, the bleached kraft fiber is hydrolyzed using an acid selected from the group consisting of sulfuric acid, mineral acid, and hydrochloric acid.

The present disclosure also provides methods of producing cellulose ethers. In some embodiments, a method of producing a cellulose ether comprises bleaching the kraft fiber of the present disclosure, treating the bleached kraft fiber with at least one alkaline agent (eg, sodium hydroxide), and reacting the fiber with at least one etherifying agent.

The present disclosure also provides methods of producing cellulose esters. In some embodiments, a method of producing a cellulose ester comprises bleaching the kraft fiber of the present disclosure, treating the bleached kraft fiber with a catalyst such as sulfuric acid, and then treating the fiber with at least one acetic anhydride or acetic acid. In an alternate embodiment, the method of producing cellulose acetate comprises bleaching the kraft fiber of the present disclosure, hydrolyzing the bleached kraft fiber with sulfuric acid, and treating the hydrolyzed kraft fiber with at least one acetic anhydride or acetic acid.

The present disclosure also provides methods of producing microcrystalline cellulose. In some embodiments, a method of producing microcrystalline cellulose comprises providing the bleached kraft fiber of the present disclosure using at least one acid hydrolyzed bleached kraft fiber until the desired DP is achieved or under conditions to achieve stable DP. In another embodiment, the hydrolyzed bleached kraft fiber is treated mechanically (e.g., by milling, grinding, or shearing). Methods known to those skilled in the art for mechanically treating hydrolyzed kraft fibers in the production of microcrystalline cellulose are provided and the desired particle size can be provided. Other parameters and conditions for the production of microcrystalline cellulose are known and are described in, for example, U.S. Patent Nos. 2,978,446 and 5,346,589.

In some embodiments, the modified kraft fiber of the present disclosure is further treated with an alkaline or caustic agent to reduce its viscosity and/or degree of polymerization. Alkaline treatment (pH above about 9) causes the dialdehyde to react and beta-hydroxy elimination. This further modified fiber treated with an alkaline agent can also be used to produce paper towels, towels and other absorbent products and cellulose derivative applications. In more conventional papermaking, strength agents are usually added to the fiber slurry. To modify the physical properties of the final product. This alkali modified fiber can be used in place of some or all of the strength modifiers used to produce paper towels and towel products.

As noted above, there are three types of fiber products that can be made by the processes set forth herein. The first type is a fiber that is treated by catalytic oxidation, which fiber is almost indistinguishable from its conventional counterpart (at least in terms of physical and paper properties), but which has functionalities associated therewith to impart one or more of the following properties: : Odor control properties, compressibility, low and ultra low DP and / or "in situ" conversion to low DP / under alkaline or acid hydrolysis conditions (such as cellulose derivative production (such as ether or acetate) production conditions) The ability of low viscosity fibers. The physical properties and papermaking properties of such fibers make them suitable for typical paper and absorbent product applications. On the other hand, increased functionality (e.g., aldehydes and carboxylic acids) and properties associated with such functionality make the fibers more desirable and versatile than standard kraft fibers.

The second type of fiber is subjected to catalytic oxidation and then treated with a caustic or caustic agent. The alkaline agent causes the fibers to decompose at sites of increased carbonyl functionality via the oxidation process. This fiber has physical and papermaking properties different from those of fibers that are only subjected to oxidation, but can exhibit the same or similar DP values because the fibers used to measure the viscosity and thus the DP are subjected to caustic reagents. Those skilled in the art will appreciate that different alkaline reagents and levels can provide different DP values.

The third type of fiber is a fiber that undergoes catalytic oxidation and is then treated in an acid hydrolysis step. Acid hydrolysis allows the fibers to decompose to the same extent as their stable DP.

In some embodiments, the fibers produced as described may be treated with a surfactant. The surfactant used in the present invention may be a solid or a liquid. The surfactant can be any surfactant, including but not limited to softeners, debonding agents, and surfactants that are non-essential to the fibers (ie, do not interfere with their specific absorption rate). As used herein, a surfactant that is "non-substantial" to the fiber exhibits a 30% or less increase in specific absorption, as measured using the pfi test as set forth herein. According to an embodiment, the specific absorption rate is increased by 25% or less, such as 20% or less, such as 15% or less, such as 10% or less. Not expected to be limited In theory, the addition of a surfactant results in competition with the test fluid for the same site on the cellulose. Therefore, when the surfactant has an excessively substantial substance, it reacts at a too many sites, thereby reducing the absorption capacity of the fiber.

As used herein, PFI was measured according to the SCAN-C-33:80 test standard, Scandinavian Pulp, Paper and Board Testing Committee. This method is generally as follows. First, a sample was prepared using a PFI pad machine. The vacuum was turned on and approximately 3.01 g of fluff pulp was supplied to the pad feeder inlet. Turn off the vacuum, remove the test part and place it on the balance to check the quality of the pad. The fluff mass was adjusted to 3.00 + 0.01 g and recorded as dry mass. Place the fluff in the test cylinder. The cylinder containing the fluff is placed in a shallow porous disk of the absorption tester and the water valve is opened. Apply a slight load of 500g to the pile mat while lifting the test unit cylinder and quickly pressing the start button. The tester will run for 30 seconds before the display reads 00.00. When the display reads 20 seconds, the height of the dry pad (dry height) of the nearest 0.5 mm is recorded. When the display reads again 00.00, press the start button again to cause the tray to automatically raise the water and then record the display time (absorption time, T). The tester continues to run for 30 seconds. The water tray is automatically lowered and run for another 30 seconds. When the display reads 20s, the wet pad height (wet height) of the nearest 0.5 mm is recorded. The sample holder is removed and the wet pad is transferred to the balance for measuring the wet mass and closing the water valve. The specific absorption rate (s/g) is T/dry mass. The specific capacity (g/g) is (wet mass - dry mass) / dry mass. The wet volume (cc/g) was [19.64 cm 2 × wet height / 3]/10. The dry volume is [19.64 cm 2 × dry height / 3]/10. The reference standard used for comparison with surfactant treated fibers does not add the same fibers of the surfactant.

It is agreed that softeners and debonders are usually only purchased as complex mixtures rather than as a single compound. While the following discussion focuses on the primary materials, it should be understood that commercially available mixtures are typically used in practice. Suitable softeners, debonders and surfactants are readily apparent to those skilled in the art and are widely reported in the literature.

Suitable surfactants include non-essential cationic surfactants, anionic surfactants, and nonionic surfactants. According to an embodiment, the surface is alive The agent is a nonionic surfactant. According to an embodiment, the surfactant is a cationic surfactant. According to an embodiment, the surfactant is a vegetable based surfactant, such as a vegetable based fatty acid, such as a vegetable based fatty acid quaternary ammonium salt. These compounds include DB999 and DB1009 available from Cellulose Solutions. Other surfactants may include, but are not limited to, Berol 388 (ethoxylated nonylphenol ether) from Akzo Nobel and TQ-2021 and TQ-2028 from Ashland Corporation.

Biodegradable softeners can be utilized. Representative biodegradable cationic softeners/debonding agents are disclosed in U.S. Patent Nos. 5,312,522, 5, 415, 737, 5, 262, 007, 5, 264, 082, and 5, 223, 096, the entire contents of each of which are incorporated herein by reference. The compound is a biodegradable diester of a quaternary ammonia compound, a quaternized ammonium amine ester, and a vegetable oil-based biodegradable compound having a quaternary ammonium chloride and a diester dimethyl dimethyl ammonium chloride functional group. Ester is a representative biodegradable softener.

Surfactants are added in amounts of up to 8 lbs/ton, such as from 2 lbs/ton to 7 lbs/ton, such as from 4 lbs/ton to 7 lbs/ton, such as from 6 lbs/ton to 7 lbs/ton.

The surfactant may be added at any point prior to the formation of the roll, bag or sheet of pulp. According to an embodiment, the surfactant is added just before the head box of the pulp machine, in particular at the entrance of the large sand removal pump.

According to one embodiment, the fibers of the present invention have improved filtration rates compared to the same fibers that do not contain a surfactant when used in a mucus process. For example, the mucus solution comprising the fibers of the invention has a filtration rate that is at least 10% lower than the mucus solution prepared in the same manner using the same fiber without the surfactant, such as at least 15% lower, such as at least 30% lower, such as At least 40% lower. The filtration rate of the mucus solution was measured by the following method. Place the solution in a nitrogen-pressed (27 psi) vessel with a 19/16 inch filter orifice at the bottom - filter media from the outside to the inside of the vessel as follows: porous metal disc, 20 mesh stainless steel mesh, thin Gauze, Whatman 54 filter paper and double flannel with the fluff side up towards the contents of the vessel. The solution was filtered through the medium over 40 minutes and then for an additional 140 minutes of 40 minutes. (Thus, at 40 minutes, t=0), the elapsed time is used as the X coordinate and the weight of the filtered mucus is used as the Y coordinate to measure (weight) the volume of the filtered solution - the slope of this plot is the filtered value. Recording was performed at 10 minute intervals. The reference standard used for comparison with surfactant treated fibers does not add the same fibers of the surfactant.

In accordance with an embodiment of the present invention, the surfactant treated fibers of the present invention exhibit a limited increase in specific absorption (e.g., less than 30%), while at the same time having a reduced filtration rate (e.g., at least 10%). According to an embodiment, the surfactant treated fiber has an increased specific absorption of less than 30% and a reduced filtration rate of at least 20% (eg, at least 30%, such as at least 40%). According to another embodiment, the surfactant treated fiber has an increased specific absorption of less than 25% and a reduced filtration rate of at least 10% (eg, at least about 20%, such as at least 30%, such as at least 40%). According to yet another embodiment, the surfactant treated fiber has an increased specific absorption of less than 20% and a reduced filtration rate of at least 10% (eg, at least about 20%, such as at least 30%, such as at least 40%). According to another embodiment, the surfactant treated fiber has an increased specific absorption of less than 15% and a reduced filtration rate of at least 10% (eg, at least about 20%, such as at least 30%, such as at least 40%). According to another embodiment, the surfactant treated fiber has an increased specific absorption of less than 10% and a reduced filtration rate of at least 10% (eg, at least about 20%, such as at least 30%, such as at least 40%).

IV. Products made from kraft fiber

The present disclosure provides products made from the modified kraft fiber described herein. In some embodiments, the products are typically made from standard kraft fiber. In other embodiments, the products are typically made from lint or sulfite pulp. More specifically, the modified fibers of the present invention can be used to produce absorbent products without any further modification and as a starting material for the preparation of chemical derivatives such as ethers and esters. To date, there have been no fibers that can be used to replace high alpha cellulose (such as cotton and sulfite pulp) as well as conventional kraft fibers.

Such as "can replace cotton lint (or sulfite pulp)..." and "can be used interchangeably with cotton linters (or sulfite pulp)..." and "can be used to replace lint ( Or a sulphite pulp) and the like, and the like only means that the fiber has properties suitable for use in the final application made from cotton linters (or sulfite pulp). This phrase is not intended to mean that the fibers must have all of the same characteristics as lint (or sulfite pulp).

In some embodiments, the product is an absorbent product, including but not limited to medical devices (including wound care (eg, bandages)), baby diapers, care pads, adult incontinence products, feminine hygiene products (eg, including sanitary napkins and cotton balls), Airflow nonwoven products, airflow composites, "desktop" handkerchiefs, napkins, paper towels, towels and the like. The absorbent product of the present disclosure may be disposable. In these embodiments, the modified fibers of the present invention may completely or partially replace the bleached hardwood or softwood fibers typically used to produce such products.

In some embodiments, the modified cellulosic fibers are in the form of fluff pulp and have one or more properties that render the modified cellulosic fibers more effective than conventional fluff pulp in absorbent products. More specifically, the modified fibers of the present invention have improved compressibility and improved odour control which are desirable to replace currently available fluff pulp fibers. Because of the improved compressibility of the fibers of the present disclosure, they can be used in embodiments that seek to create a thinner, more compact absorbent structure. After understanding the compression properties of the fibers of the present disclosure, those skilled in the art can readily design absorbent products that can utilize such fibers. For example, in some embodiments, the present disclosure provides an ultra-thin sanitary product comprising the modified kraft fiber of the present disclosure. Ultra-thin fluff cores are commonly used, for example, in feminine hygiene products or baby diapers. Other products that may be produced using the fibers of the present disclosure may be any that require an absorbent core or a compressed absorbent layer. The fibers of the present invention do not exhibit absorptive loss or substantial absorptive loss upon compression, but exhibit improved flexibility.

According to an embodiment, the absorbent product can be a product that absorbs and retains urine, such as a diaper or an incontinence device. These devices typically contain an absorbent fluff core. The fibers of the present disclosure can be used to create an absorbent device that can improve urinary wicking and retention, thereby resulting in a more Comfortable clothes or equipment.

The fibers of the present disclosure may improve vertical wicking, horizontal wicking, and/or 45 degree wicking. According to one embodiment, the absorbent product made using the fibers of the present disclosure improves vertical wicking by 10% compared to products made from fibers that have not been subjected to the oxidation step. According to another embodiment, the absorbent product made using the fibers of the present disclosure improves vertical wicking by 15% compared to products made from fibers that have not been subjected to the oxidation step. According to yet another embodiment, the absorbent product made using the fibers of the present disclosure improves vertical wicking by 20% compared to products made from fibers that have not been subjected to the oxidation step. Similar improvements can be seen in horizontal and 45 degree wicking.

The fibers of the present disclosure improve the rate of absorption and retention. According to one embodiment, the absorbent product made using the fibers of the present disclosure improves the rate of absorption by 10% compared to products made from fibers that have not been subjected to the oxidation step. According to another embodiment, the absorbent product made using the fibers of the present disclosure improves the rate of absorption by 15% compared to products made from fibers that have not been subjected to the oxidation step. According to yet another embodiment, the absorbent product made using the fibers of the present disclosure improves the rate of absorption by 20% compared to products made from fibers that have not been subjected to the oxidation step. Similar improvements can be seen in horizontal and 45 degree wicking. Similarly, according to one embodiment, the absorbent product made using the fibers of the present disclosure will have a total absorption improvement of 5% compared to a product made from fibers that have not been subjected to the oxidation step. According to another embodiment, the absorbent product made using the fibers of the present disclosure improves the total absorption by 10% compared to a product made from fibers that have not been subjected to the oxidation step. According to yet another embodiment, the absorbent product made using the fibers of the present disclosure improves the total absorption by 15% compared to products made from fibers that have not been subjected to the oxidation step.

Compared to products made from fibers that have not been subjected to an oxidation step, the products described exhibit improved flexibility (especially when used on the curved side of a multilayer core), improved dimensional stability (after stimulation), and improved Wet and dry strength (especially when the disclosed fibers are placed in the top layer of the multilayer core) and elongation.

According to an embodiment, the absorbent core used in the absorbent device can comprise one or more fibrous layers that are treated differently to improve overall uptake and retention of the device. As used herein, treatment refers to any chemical or physical process that alters the absorbency, wicking, or retention of a fiber. One common treatment is the addition of a surfactant. According to an embodiment, the core may have multiple layers, such as 2, 3, 4 or 5. According to one embodiment, the fibers of the present invention can be used in any of the layers of the multilayer absorbent core and can be treated or untreated.

According to another embodiment, the fibers of the invention are used in the top layer of the absorbent core. As used herein, "top" refers to the point on the core that is first stimulated by the urine and closest to the skin. Similarly, "bottom" refers to the layer that is farthest from the user. Other layers may be referred to as "intermediate layers." The fibers of the present disclosure may be used in an "untreated" state, which means that the fibers have not been post-treated, for example, using a surfactant. Fibers can also be used in a "treated" state, which means that the fibers are modified by the inclusion of a surfactant. Treated or untreated fibers can be used in either layer or in any combination.

According to an embodiment, the fibers of the invention are used in the top layer of the absorbent core. According to another embodiment, the fibers of the invention are used in the bottom layer of the absorbent core. According to a further embodiment, the fibers of the invention are used in an intermediate layer of an absorbent core.

In another embodiment, the fibers of the present disclosure are used in more than one absorbent core layer. The fibers of the present disclosure can be used to absorb the top and bottom layers of the core. Additionally, the fibers of the present disclosure can be used to absorb the top, bottom, and intermediate layers of the core. According to an embodiment, the fibers in the top layer are treated fibers. According to another embodiment, the fibers in the bottom layer are treated fibers. According to a further embodiment, the fibers in the intermediate layer are treated fibers.

The treated fibers and untreated fibers of the present disclosure may be combined in a single layer or may be used in separate layers of the absorbent core. According to an embodiment, the top layer of the absorbent core comprises the untreated fibers of the present disclosure and the bottom layer of the absorbent core comprises the treated fibers of the present disclosure. According to another embodiment, the treated fibers of the present disclosure are used to fabricate an absorption core The top layer of the heart, using the untreated fibers of the present disclosure to make one or more intermediate layers and using the treated fibers of the present disclosure to make the bottom layer.

The density of the absorbent core can vary and is typically between 0.10 g/cm ³ and 0.45 g/cm ³ . According to an embodiment, the absorbent core can have a density of about 0.15 g/cm ³ . According to another embodiment, the absorbent core can have a density of about 0.20 g/cm ³ . According to yet another embodiment, the absorbent core may have from about 0.25g / cm ³ of density.

The modified fibers of the present invention can also be used to produce absorbent products without modification, including, but not limited to, paper towels, towels, napkins, and other paper products formed on conventional papermaking machines. Conventional papermaking processes involve the preparation of an aqueous fiber slurry that is typically deposited on a forming line, on which water is subsequently removed. The increased functionality of the modified cellulosic fibers of the present disclosure provides improved product characteristics to products comprising such modified fibers. For the above reasons, the modified fibers of the present invention allow the products made therefrom to exhibit strength improvements which may be related to the increased functionality of the fibers. The modified fibers of the present invention can also provide products with improved softness.

In some embodiments, the modified fibers of the present disclosure can be used to make cellulose ethers (eg, carboxymethylcellulose) and esters in place of having a very high DP of from about 2950 to about 3980 without further modification. That is, fibers having a viscosity between about 30 mPa ‧ s and about 60 mPa ‧ s, as measured by 0.5% capillary CED) and a very high percentage of cellulose (eg, 95% or greater, such as those derived from cotton linters) And fibers of bleached softwood fibers produced by an acidic sulfite pulping process. The modified fibers of the present invention which have not been subjected to acid hydrolysis are typically subjected to this acid hydrolysis treatment in the production process for the production of cellulose ethers or esters.

As illustrated, the second and third types of fibers are produced via a process of deriving or hydrolyzing the fibers. These fibers can also be used to produce absorbent articles, absorbent paper products, and cellulose derivatives (including ethers and esters).

V. Acid/base hydrolysis products

In some embodiments, the present disclosure provides for replacing lint or sulfite Modified kraft fiber of pulp. In some embodiments, the present disclosure provides modified kraft fiber that can be used in place of lint or sulfite pulp to, for example, make cellulose ether, cellulose acetate, and microcrystalline cellulose.

Without being bound by theory, it is believed that increasing the aldehyde content relative to conventional kraft pulp provides additional activity for etherification to the final product (eg, carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, and the like). Sites, thereby enabling the production of fibers useful in papermaking and cellulose derivatives.

In some embodiments, the modified kraft fiber has chemical properties that make it suitable for the manufacture of cellulose ethers. Accordingly, the present disclosure provides cellulose ethers derived from the modified kraft fiber. In some embodiments, the cellulose ether is selected from the group consisting of ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl methyl cellulose. It is believed that the cellulose ethers of the present disclosure can be used in any application where cellulose ethers are typically used. By way of example and not limitation, the cellulose ethers of the present disclosure may be used in coatings, inks, adhesives, controlled release pharmaceutical lozenges, and films.

In some embodiments, the modified kraft fiber has chemical properties that make it suitable for making cellulose esters. Accordingly, the present disclosure provides cellulose esters, such as cellulose acetate, derived from the modified kraft fiber of the present disclosure. In some embodiments, the present disclosure provides a product comprising cellulose acetate derived from the modified kraft fiber of the present disclosure. By way of example and not limitation, cellulose esters of the present disclosure may be used in household furniture, cigarettes, inks, absorbent products, medical devices, and plastics (eg, including LCD and plasma screens and windshields).

In some embodiments, the modified kraft fiber has chemical properties that make it suitable for making microcrystalline cellulose. Microcrystalline cellulose produces a highly purified starting cellulosic material that requires relatively cleanliness. Therefore, expensive sulfite pulp has been used mainly for its production. The present disclosure provides microcrystalline cellulose derived from the modified kraft fiber of the present disclosure. Accordingly, the present disclosure provides cost effective cellulose for the production of microcrystalline cellulose source. In some embodiments, the microcrystalline cellulose is derived from a modified kraft fiber having a DP of less than about 100 (eg, less than about 75 or less than about 50). In some embodiments, the microcrystalline cellulose is derived from an R10 value of between about 65% to about 85% (eg, from about 70% to about 85% or from about 75% to about 85%) and the R18 value is between about From 75% to about 90% (e.g., from about 80% to about 90%, such as from about 80% to about 87%) of modified kraft fiber.

The modified cellulose of the present disclosure can be used in any application where microcrystalline cellulose is typically used. By way of example and not limitation, the modified cellulose of the present disclosure can be used in pharmaceutical or nutritional applications, food applications, cosmetic applications, paper applications, or as structural composites. For example, the modified cellulose of the present disclosure may be a binder, a diluent, a disintegrant, a lubricant, a tableting aid, a stabilizer, a tempering agent, a fat substitute, an accumulating agent, an anti-caking agent. , a foaming agent, an emulsifier, a thickener, a separating agent, a gelling agent, a carrier material, an opacifier or a viscosity modifier. In some embodiments, the microcrystalline cellulose is a gel.

VI. Products including acid hydrolysis products

In some embodiments, the present disclosure provides a pharmaceutical product comprising microcrystalline cellulose produced from modified kraft fiber of the present disclosure that has been hydrolyzed. The pharmaceutical product can be any pharmaceutical product that typically uses microcrystalline cellulose. By way of example and not limitation, the pharmaceutical product may be selected from the group consisting of tablets and capsules. For example, the microcrystalline cellulose of the present disclosure can be a diluent, a disintegrant, a binder, a compression aid, a coating, and/or a lubricant. In other embodiments, the disclosure provides a pharmaceutical product comprising at least one modified derivatized kraft fiber (eg, hydrolyzed modified kraft fiber) of the present disclosure.

In some embodiments, the present disclosure provides a food product comprising bleached kraft fiber of the present disclosure that has been hydrolyzed. In some embodiments, the present disclosure provides a food product comprising at least one product derived from the bovine bleached paper fibers of the present disclosure. In other embodiments, the present disclosure provides a food product comprising microcrystalline cellulose derived from the kraft fiber of the present disclosure. In some embodiments, the food product comprises colloidal microcrystalline cellulose derived from the kraft fiber of the present disclosure. Food products can It is any food product that usually uses microcrystalline cellulose. Those skilled in the art are familiar with exemplary food types that can use microcrystalline cellulose and can be found, for example, in the Food Standard (Codex Alimentarius) (e.g., Table 3). For example, microcrystalline cellulose derived from chemically modified kraft fiber of the present disclosure may be an anti-caking agent, a bulking agent, an emulsifier, a foaming agent, a stabilizer, a thickener, a gelling agent, and/or Suspending agent

Those skilled in the art can also design other products including cellulose derivatives and microcrystalline cellulose derived from chemically modified kraft fibers of the present disclosure. Such products can be found, for example, in cosmetic and industrial applications.

As used herein, "about" is intended to explain the variation caused by experimental error. Unless otherwise stated, all measurements are to be understood as modified by the word "about," whether or not explicitly stated as "about." Thus, for example, the statement "a fiber having a length of 2 mm" is understood to mean "a fiber having a length of about 2 mm".

The details of one or more non-limiting embodiments of the invention are set forth in the examples below. Other embodiments of the invention will be apparent to those skilled in the <RTIgt;

Instance A. Test plan

1. Measure the caustic solubility (R10, S10, R18, S18) according to TAPPI T235-cm00.

2. Measure the carboxyl content according to TAPPIT237-cm98.

3. Measure the aldehyde content according to the special procedure ESM 055B of Econotech Services Ltd.

4. Measure the copper value according to TAPPI T430-cm99.

5. Calculate the carbonyl content from the copper value according to the formula: carbonyl = (copper value - 0.07) / 0.6 ( Biomacromolecules 2002, 3, 969-975).

6. Measure the 0.5% capillary CED viscosity according to TAPPI T230-om99.

7. Measure the intrinsic viscosity according to ASTM D1795 (2007).

8. Since the 0.5% CED viscosity according to capillary formula: calculating DP DPw = -449.6 + 598.4ln (0.5 % capillary CED) + 118.02ln ² (0.5% capillary CED), 1994Cellucon Conference, disclosed in The Chemistry and Processing Of Wood And Plant Fibrous Materials , p. 155, Woodhead Publishing Ltd., Abington Hall, Abington, Cambridge CBI 6AH, England, JF Kennedy et al.

9. Measure carbohydrates by Dionex ion chromatography analysis according to TAPPI T249-cm00.

10. From the carbohydrate composition according to the formula: cellulose = dextran - (mannan / 3) to calculate the cellulose content, TAPPI Journal 65 (12): 78-801982.

11. Calculate the hemicellulose content from the sum of the sugar content minus the cellulose content.

12. from OPTEST, the Hawkesbury, Ontario the Fiber Quality Analyzer ^TM measured according to the standard procedures manufacturer cellulose length and roughness.

13. Determine the wet zero tension according to TAPPI T273-pm99.

14. Determine the degree of freedom according to TAPPI T227-om99.

15. Determine the water retention value according to TAPPI UM 256.

16. The DCM (dichloromethane) extract was determined according to TAPPI T204-cm97.

17. Determination of iron content by acid digestion and analysis and by ICP.

18. Determine the ash content according to TAPPI T211-om02.

19. Determine residual peroxide according to the Interox program.

20. Measure brightness according to TAPPI T525-om02.

21. Porosity was determined according to TAPPI 460-om02.

22. The burst factor was determined according to TAPPI T403-om02.

23. Determination of the anti-crack factor according to TAPPI T414-om98.

24. Determine the length and elongation of the fracture according to TAPPI T494-om01.

25. Opacity was determined according to TAPPI T425-om01.

26. Frazier porosity was determined according to the manufacturer's procedure on a Frazier Low Air Permeability Instrument from Frazier Instruments, Hagerstown, MD.

27. Fiber length and form factor were determined on an L&W fiber tester from Lorentzen & Wettre, Kista, Sweden according to the manufacturer's standard procedure.

28. Determine dust and debris according to TAPPI T213-om01.

B. An Exemplary Method of Making Modified Cellulose Fibers

Semi-bleached or substantially bleached kraft pulp can be treated with acid, iron and hydrogen peroxide for reducing the viscosity or DP of the fibers. The fibers can be adjusted to a pH of from about 2 to about 5, if not already in this range, using sulfuric acid, hydrochloric acid, acetic acid or a filtrate from a scrubber of an acid bleaching stage (e.g., chlorine dioxide stage). Iron in the form of Fe ⁺² may be added, for example, iron in the form of ferrous sulfate heptahydrate (FeSO ₄ 7H ₂ O) may be added. The ferrous sulfate may be dissolved in water at a concentration of between about 0.1 g/L to about 48.5 g/L. The ferrous sulfate solution can be added at an application rate between about 25 ppm and about 200 ppm (in the form of Fe ^{+ 2} , based on the dry weight of the pulp). The ferrous sulfate solution can then be thoroughly mixed with the pH adjusting pulp (consistency from about 1% to about 15%, measured as the dry pulp content of the total wet pulp mass). The aqueous hydrogen peroxide (H ₂ O ₂ ) solution can then be added in a concentration of from about 1% by weight to about 50% by weight H ₂ O ₂ and in an amount from about 0.1% to about 3% (based on the dry weight of the pulp). The pulp mixed with ferrous sulfate and peroxide (pH from about 2 to about 5) can be reacted at a temperature of from about 60 ° C to about 80 ° C for a time between about 40 minutes and about 80 minutes. The decrease in viscosity (or DP) depends on the amount of peroxide consumed in the reaction, which varies with the concentration and amount of peroxide and iron applied, and the residence time and temperature.

The treatment can be achieved using a standard sequence D ₀ E1 D1 E2 D2 in a typical 5-stage bleaching plant. With this solution, no additional tanks, pumps, mixers, towers or scrubbers are required. Stage 4 or E2 can be preferably used for processing. The fibers on the D1 stage scrubber can be adjusted to a pH of from about 2 to about 5 as needed by the addition of acid or filtrate from the D2 stage. The ferrous sulfate solution can be added to the pulp by: (1) spraying it onto the D1 stage scrubber mat via an existing sprinkler or new head, and (2) adding it via a spray mechanism at the pulper, Or (3) via the addition point before the mixer or pump used in stage 4. The peroxide solution can be added after the ferrous sulfate at the point of addition in the mixer or pump prior to the Stage 4 column. It is also possible to add steam before the tower in the steam mixer as needed. The pulp can then be reacted in the column for an appropriate residence time. The chemically modified pulp can then be washed in a normal manner on a Stage 4 scrubber. Additional bleaching may be achieved after treatment by the fifth or D2 stage of operation in the normal manner.

Example 1 Method of making the fibers of the present disclosure A. Grinding method A

The southern pine cellulose is digested and oxygen delignification is carried out in a conventional two-stage oxygen delignification step until the Kappa number is from about 9 to about 10. The de-lignin pulp was bleached in a 5-stage bleaching apparatus using the sequence D ₀ (EO) D1E2D2. Prior to stage 4 or E2, the pH of the pulp is adjusted to a range of from about 2 to about 5 using the filtrate from stage D of the sequence. After adjusting the pH, 0.2% hydrogen peroxide (based on the dry weight of the pulp) and 25 ppm Fe ⁺² (in the form of FeSO ₄ .7H ₂ O, based on the dry weight of the pulp) were added to the kraft fiber in the E2 stage column and at about 78 The reaction is carried out at a temperature of from ° C to about 82 ° C for about 90 minutes. The reacted fibers are then washed on a Stage 4 scrubber and then bleached in the 5th (D2) stage using chlorine dioxide.

B. Grinding method B

The fibers were prepared as described in Grinding Method A except that the pulp was treated with 0.6% peroxide and 75 ppm Fe ⁺² .

C. Grinding method C

The fibers were prepared as described in Grinding Method A except that the pulp was treated with 1.4% peroxide and 100 ppm Fe ⁺² .

Instance fiber properties

After the above 5-stage bleaching sequence, fiber samples obtained according to the grinding methods A (sample 2), B (sample 3), and C (sample 4) were collected. According to the above-described embodiment to measure the level of such sample and the standard fluff fibers (GP Leaf River Cellulose, New Augusta , MS; sample 1) and commercial samples (PEACH ^TM, sold by Weyerhaeuser Company; sample 5) of several nature. The results of these measurements are reported in Table 1 below.

As reported in Table 1, the iron content of the control fiber (Sample 1) was not measured. However, the iron content of the four milled pulp samples treated under the same conditions as those reported for the sample 1 was obtained. The iron content of these samples averaged 2.6 ppm. Therefore, for Sample 1, the iron content is expected to be about 2.5 ppm.

As can be seen from Table 1, unexpectedly, the modified fiber of the present invention and the control fiber (sample 1) and the alternative commercially available oxidized fiber (sample 5) have a total carbonyl content, a carboxyl group content, and an aldehyde content. different. Because of the differences between the total carbonyl groups and the aldehyde groups, the additional carbonyl functional groups may be in the form of other ketones. The data demonstrates that a relatively high aldehyde content can be achieved while retaining the carboxylic acid groups while maintaining a ratio of aldehyde to total carbonyl close to 1 (as seen in Table 1, about 1.0 (0.95) to 1.6). Even more surprising is that the fibers exhibit high brightness and are relatively strong and absorbent.

As can be seen in Table 1, the standard fluff grade fiber (Sample 1) had a carboxyl group content of 3.13 meq/100 g and an aldehyde content of 0.97 meq/100 g. Low dose treatment (sample 2) with 0.2% H ₂ O ₂ and 25 ppm Fe ⁺² or higher dose treatment (sample 3) with 0.6% H ₂ O ₂ and 75 ppm Fe ⁺² or 1.4% H _{After 2} O ₂ and 100 ppm Fe ⁺² for higher dose treatment (Sample 4), the fiber length and calculated cellulose content were relatively unchanged, and the fiber strength (measured by the wet zero distance method) was slightly weakened. However, the carboxyl group, carbonyl group and aldehyde content are all increased, indicating that the cellulose is widely oxidized.

In contrast, the commercially available sample of oxidized kraft cork southern pine fiber produced by the alternative method (sample 5) exhibited a significantly reduced fiber length and fiber compared to the fluff fiber as reported in sample 1. The strength (as measured by the wet zero distance method) is about 70% lost. The aldehyde content of the sample 5 was practically unchanged compared to the standard fluff fiber, and the inventive fiber (sample 2-4) obtained by the grinding method AC had a highly elevated aldehyde content, such as about 70% to A total of about 100% of the cellulose is represented by the calculated carbonyl content. In contrast, the PEACH® aldehyde content is less than 30% of the total calculated carbonyl content of the cellulose. The ratio of total carbonyl to aldehyde appears to be a good indication of fibers having broad applicability to the modified fibers within the scope of the disclosure, especially when the ratio is in the range of from about 1 to about 2, such as Samples 2-4. Low viscosity fibers (e.g., Samples 3 and 4) having a carbonyl/aldehyde ratio of from about 1.5 to less than 2.0 maintain fiber length, whereas those of Comparative Sample 5 do not.

The freeness, density and strength of the above standard fiber (sample 1) were compared with the above sample 3. The results of this analysis are shown in Table 2.

As can be seen in Table 2 above, the freeness of the modified cellulosic fibers of the present disclosure can be comparable to standard fluff fibers that have not been subjected to oxidation treatment in the bleaching sequence.

Example 2

Treatment of OD(EOP)D(EP)D bleaching equipment using hydrogen peroxide (applying 0.25% to 1.5%) and 50 or 100 ppm Fe ⁺² (added as FeSO ₄ ‧7H ₂ O) at about 10% consistency A 0.5% capillary CED viscosity of the D1 stage was a sample of southern pine pulp of about 14.6 mPa ‧ s. An aqueous solution of Fe ^{+ 2 was} added and thoroughly mixed with the pulp. A 3% aqueous solution of hydrogen peroxide was then mixed with the pulp. The mixed pulp was kept in a water bath at 78 ° C for 1 hour. After the reaction time, the pulp was filtered and the pH of the filtrate and residual peroxide were measured. The pulp was washed and the 0.5% capillary CED viscosity was determined according to TAPPI T230. The results are shown in Table 3.

Example 3

A sample of D1 pulp having a 0.5% capillary CED viscosity of 15.8 mPa ‧ (DPw 2101) from the bleaching apparatus described in Example 2 was treated with 0.75% of the applied hydrogen peroxide, and 50 ppm was added in the same manner as in Example 2. 200 ppm Fe ⁺² , but the residence time also varies from 45 minutes to 80 minutes. The results are shown in Table 4.

Example 4

D1 pulp having a 0.5% capillary CED viscosity of 14.8 mPa ‧ (DPw 2020) from the bleaching apparatus described in Example 2 was treated in the same manner as described in Example 2 using 0.75% hydrogen peroxide and 150 ppm Fe ⁺² The sample was only treated for 80 minutes. The results are shown in Table 5.

Example 5

Treatment with hydrogen peroxide (applying 0.25 wt% or 0.5 wt% based on pulp) and 25 ppm, 50 ppm or 100 ppm Fe ⁺² (added as FeSO ₄ .7H ₂ O) at 10% consistency from OD ₀ (EO) D1 (EP) The D1 stage of the D1 stage has a 0.5% capillary CED viscosity of 15.6 mPa ‧ (DPw 2085) of southern pine pulp. An aqueous solution of Fe ^{+ 2 was} added and thoroughly mixed with the pulp. A 3% aqueous solution of hydrogen peroxide was then mixed with the pulp, and the mixed pulp was kept at 78 ° C for 1 hour in a water bath. After the reaction time, the pulp was filtered and the pH of the filtrate and residual peroxide were measured. The pulp was washed and the 0.5% capillary CED viscosity was determined according to TAPPI T230. The results are shown in Table 6.

Example 6

In the same manner as in Example 5, the 0.5% capillary CED viscosity of D1 pulp treated with 0.10%, 0.25%, 0.50% or 0.65% hydrogen peroxide and 25 ppm, 50 ppm or 75 ppm Fe ⁺² was 15.2 mPa ‧ (DPw 2053) Another sample. The results are shown in Table 7.

Example 7

Southern pine pulp was collected from the D1 stage of the OD(EO)D(EP)D bleaching sequence after increasing the degree of lignin in the kraft and oxygen stages to produce a pulp having a lower DPw or 0.5% capillary CED viscosity. The initial 0.5% capillary CED viscosity was 12.7 mPa ‧ (DPw 1834). 0.50% or 1.0% hydrogen peroxide and 100 ppm Fe ^{+2 were added} . Other treatment conditions were 10% consistency, 78 ° C and 1 hour treatment time. The results are shown in Table 8.

Example 8

In a similar manner to Example 7, the 0.5% capillary CED viscosity of the D1 pulp from the D1 stage of the OD(EO)D(EP)D sequence was treated with 0.75% or 1.0% hydrogen peroxide and 75 ppm or 150 ppm Fe ^{+2 to} be 11.5. The low viscosity sample of mPa‧s (DPw 1716) was only treated for 80 minutes. The results are shown in Table 9.

Example 9

Southern pine pulp was collected from the D1 stage of the OD(EO)D(EP)D sequence. The initial 0.5% capillary CED viscosity was 11.6 mPa ‧ (DPw 1726). 1.0%, 1.5% or 2% hydrogen peroxide and 75 ppm, 150 ppm or 200 ppm Fe ^{+2 were added} . Other treatment conditions were 10% consistency, 78 ° C and 1.5 hour treatment time. The results are shown in Table 10.

Example 10

Southern pine pulp was collected from the D1 stage of the OD(EO)D(EP)D sequence. The initial 0.5% capillary CED viscosity was 14.4 mPa ‧ (DPw 1986). 1.0%, 1.5% or 2% hydrogen peroxide and 75 ppm, 150 ppm or 200 ppm Fe ^{+2 were added} . Other treatment conditions were 10% consistency, 78 ° C and 1.5 hour treatment time. The results are shown in Table 11.

Example 11

Southern pine pulp was collected from the D1 stage of the OD(EO)D(EP)D sequence. The initial 0.5% capillary CED viscosity was 15.3 mPa ‧ (DPw 2061). Add 3% (based on pulp) hydrogen peroxide and 200 ppm Fe ⁺² . Other treatment conditions were 10% consistency, 80 ° C and 1.5 hour reaction time. The results are shown in Table 12.

Examples 2-11 above demonstrate that a significant reduction in 0.5% capillary CED viscosity and/or degree of polymerization can be achieved using the acidic, catalytic, peroxide treatments of the present disclosure. The final viscosity or DPw seems to depend on the amount of peroxide consumed by the reaction, as shown in Figure 1, which reports the viscosity of the pulp from two different plants ("Brunswick" and Leaf River ("LR")). The percentage change in the percentage of peroxide consumed. The peroxide consumed varies depending on the amount and concentration of peroxide and iron applied, the reaction time, and the reaction temperature.

Example 12

Southern pine pulp was collected from the D1 stage of the OD(EO)D(EP)D sequence. The initial 0.5% capillary CED viscosity was 14.8 mPa ‧ (DPw 2020). Add 1% (pulp based pulp) hydrogen peroxide and add 100 pm, 150 pm or 200 pm Cu ⁺² (in the form of CuSO ₄ .5H ₂ O). Other treatment conditions were 10% consistency, 80 ° C and 3.5 hour reaction time. The results are shown in Table 13.

The use of copper instead of iron slows the reaction and reduces the lower viscosity reduction compared to the untreated control pulp, but still significantly changes the viscosity, carboxyl content and aldehyde content.

Example 13

The E2 (EP) stage of the OD (EOP) D (EP) D sequence was changed to produce ultra low polymerization degree pulp. FeSO _{4 was} ^{fed in the} form of Fe ⁺² at an application rate of 150 ppm at the D1 stage scrubber. The 7H ₂ O solution was sprayed onto the pulp. Caustic (NaOH) was not added to the E2 stage and the peroxide application was increased to 0.75%. The residence time was about 1 hour and the temperature was 79 °C. The pH was 2.9. And then washed using 0.7% ClO ₂ treatment at 91 ℃ D2 for about 2 hours at the final stage vacuum drum washer on the treated pulp. The final 0.5% capillary CED viscosity of the bleached pulp is 6.5 mPa. s (DPw 1084) and ISO brightness is 87.

Example 14

The pulp produced in Example 13 was made into a pulp board on a Fourdrinier type pulp dryer having a standard dryer. A sample of the control pulp and the pulp of the invention (ULDP) was collected and analyzed for chemical composition and fiber properties. The results are shown in Table 14.

Treated pulp (ULDP) has a higher 10% and 18% NaOH alkaline solubility and a higher aldehyde and total carbonyl content. The DP of ULDP is significantly lower, as measured by a 0.5% capillary CED viscosity. Fiber integrity is also reduced by a reduction in wet zero tensile strength. Although the DPw is significantly reduced, the fiber length and freeness are substantially unchanged. There is no detrimental effect on drainage or board manufacture on the machine.

Example 15

In a similar manner to Example 13, the E2 (EP) stage of the OD(EO)D(EP)D sequence was changed to produce an ultra-low polymerization degree pulp. In this example, 75 ppm FeSO _{4 was} added. 7H ₂ O (in the form of Fe ⁺² ) and hydrogen peroxide applied in the E2 stage was 0.6%. The pH of the treatment stage was 3.0, the temperature was 82 ° C, and the residence time was about 80 minutes. The pulp was washed and then treated with 0.2% ClO ₂ in the D2 stage at 92 ° C for approximately 150 minutes. The 0.5% capillary CED viscosity of the fully bleached pulp was 5.5 mPa ‧ (DPw 914) and the ISO brightness was 88.2.

Example 16

Pulped plate Fourdrinier type having an air cushion on the pulp dryer Flakt ^TM dryer section the pulp produced in Example 15 of. Samples of standard pulp and pulp of the invention (ULDP) were collected and analyzed for chemical composition and fiber properties. The results are shown in Table 15.

Treated pulp (ULDP) has a higher 10% and 18% NaOH alkaline solubility and a higher aldehyde and total carbonyl content. The DP of ULDP is significantly lower (as measured by 0.5% capillary CED viscosity) and has a lower wet zero break length. The brightness is still an acceptable value of 88.2. The treatment maintains fiber length and freeness and has no operational problems with respect to forming and drying the sheet.

Example 17

In a similar manner to Example 13, the E2 (EP) stage of the OD(EO)D(EP)D sequence was changed to produce a pulp of low degree of polymerization. In this case, 25 ppm FeSO _{4 was} added. 7H ₂ O (in the form of Fe ⁺² ) and hydrogen peroxide applied in the E2 stage was 0.2%. The pH of the treatment stage was 3.0, the temperature was 82 ° C, and the residence time was about 80 minutes. The pulp was washed and then treated with 0.2% ClO ₂ in the D2 stage at 92 ° C for approximately 150 minutes. The 0.5% capillary CED viscosity of the fully bleached pulp was 8.9 mPa ‧ (DPw 1423) and the ISO brightness was 89.

Example 18

Pulped plate Fourdrinier type having an air cushion on the pulp dryer Flakt ^TM dryer section the pulp produced in Example 15 of. A sample of the standard pulp and the low polymerization degree pulp (LDP) of the present invention was collected and analyzed for chemical composition and fiber properties. The results are shown in Table 16.

Treated pulp (ULDP) has a higher 10% and 18% NaOH alkaline solubility and a higher aldehyde and total carbonyl content. The DP of LDP is lower, as measured by a 0.5% capillary CED viscosity. Brightness has minimal loss. The treatment maintains fiber length and has no operational problems with respect to forming and drying the sheet.

Example 19

The pulp board set forth in Example 14 was fiberized and air formed into a 4" x 7" mat using a Kamas laboratory hammer mill (Kamas Industries, Sweden). The laboratory press was then used to compress the air forming mat under various gauge pressures. After compression, the thickness of the pad was measured using a 200-A Emveco Precision Ultrasonic Thickness Gauge with a plantar pressure of 0.089 psi. The mat density is calculated from the weight and thickness of the mat. The results are shown in Table 17.

The data in Table 17 demonstrates that the resulting modified fibers within the scope of the present disclosure are more compressible, resulting in a thinner and higher density structure that is more suitable for current disposable absorbent product designs.

Without being bound by theory, it is believed that oxidation of the cellulose destroys the crystalline structure of the polymer, resulting in less stiffness and greater compliance. Fiber composed of modified cellulose structure It then becomes more compressive, resulting in a higher density absorption structure.

Example 20

Southern pine pulp was collected from the D1 stage of the OD(EO)D(EP)D sequence. The initial 0.5% capillary CED viscosity was 14.9 mPa ‧ (DPw 2028). 1.0% or 2% hydrogen peroxide and 100 ppm or 200 ppm Fe ⁺² were added, respectively. Other treatment conditions were 10% consistency, 80 ° C and 1 hour residence time. The fluff pulp was then slurried using deionized water, wet laid on a screen to form a fiber mat, dewatered via a roller press, and dried at 250 °F. The dried sheets were defibrated and air formed into a 8.5 gram 4" x 7" air cloth mat (air dried) using a Kamas laboratory hammer mill (Kamas Industries, Sweden). A single intact cover sheet of nonwoven fabric was applied to one side of each pad and the sample was densified using a Carver hydraulic flat press applying a load of 145 psig.

The pads were placed in an individual 1.6 L airtight plastic container with a removable cover fitted with an inspection valve and a sampling port with a 1⁄4" ID Tygon® tube. Before fixing the container lid, at room temperature next, 60 g of deionized water and 0.12 g of 50% NH ₄ OH stimulus poured on the center of the delivery device 1 "ID vertical tube, the delivery device capable of applying a load to the entire specimen 0.1psi. After the irritant is completely absorbed, the delivery device is removed from the sample, the lid with the sealed sampling cassette is assembled to the container, and the countdown timer is turned on. At the end of 45 minutes, a headspace sample was taken from a sampling port with an ammonia selective short-term gas detection tube and an ACCURO® bellows pump (all available from Draeger Safety, Pittsburgh, PA). The data in Table 18 demonstrates that the modified fibers produced within the scope of the present disclosure are capable of reducing the amount of ammonia in the headspace, resulting in a repressible volatile malodorous compound (usually cited as unpleasant in wetting incontinence products) The structure of the substance).

Example 21

In a similar manner to Example 14, the E2 stage of the OD(EO)D(EP)D sequence of a commercial kraft pulping facility was varied to produce a low degree of polymerization pulp. In this example, 100 ppm FeSO ₄ ‧7H ₂ O (in the form of Fe ⁺² ) was added and the hydrogen peroxide applied in the E2 stage was 1.4%. The pulp properties are shown in Table 19.

Plate pulped chemically modified cellulose produced by the Fourdrinier type having a pulp dryer on the dryer section of the air cushion Flakt ^TM. Defibration of this product and a sample of the control kraft pulp board was carried out using a Kamas laboratory hammer mill. Optical analysis of the fiber properties of the Kamas pre- and Kamas-milled samples was performed according to the manufacturer's protocol using a HiRes fiber quality analyzer available from Optest Equipment, Inc., Hawkesbury, ON, Canada. The results are shown in the table below.

As can be seen in Table 20, the knots and crimps of the ULDP fibers made according to the present disclosure were higher than the control fibers not treated with iron and peroxide.

The above defibrated fibers were air formed into 4" x 7" mats (air dried) weighing 4.25 grams. The sodium polyacrylate superabsorbent (SAP) particles derived from BASF were uniformly applied between two 4.25 gram mats. A fully covered nonwoven fabric was applied to the top surface of the fiber/SAP matrix and the mat was densified by a 145 psig load applied via a Carver flat press.

The synthetic urine was prepared by the following manner: 2% urea, 0.9% NaCl and 0.24% nutrient broth (Criterion ^TM brand, available via Hardy Diagnostics, Santa Maria, CA) dissolved in deionized water, and add a normal An aliquot of Proteus Vulgaris was used to obtain an initial bacterial concentration of 1.4 x 10 ⁷ CFU/ml. The pad was then placed in the headspace chamber as described in Example 20 and stimulated with 80 ml of synthetic urine solution. Immediately after the stimulation, the chamber was sealed and placed in an environment at a temperature of 30 °C. Dräger sampling was continuously performed at 4 hour and 7 hour intervals. The experiment was repeated three times and the average results are reported in Table 21.

As can be seen from the data, atmospheric ammonia derived from the hydrolysis of urea bacteria is less than the standard kraft paper used in the composite structure of modified cellulose fibers produced in the scope of the present disclosure (which is similar in construction to retail urinary incontinence products). A composite structure produced by pine fibers. Thus, the odor control properties of the structure comprising the modified cellulosic fibers of the present disclosure are superior to standard kraft southern pine fibers.

Example 22 - Comparison of Stage 4 and Post-bleaching Treatment

Southern pine pulp was collected from the D1 stage of the OD(EO)D1(EP)D2 sequence. The initial 0.5% capillary CED viscosity is 14.1mPa. s. 1.5% hydrogen peroxide (based on dry pulp weight) and 150 ppm Fe ^{+2 were added} . As used herein, "P*" is used to indicate the iron and hydrogen peroxide treatment stages. In the fourth stage of the sequence, treatment was carried out for 1 hour at a temperature of 10% consistency and 78 °C. The treated pulp was then washed and bleached for 2 hours at ₂₈ ° C using 0.25% ClO ₂ in the D2 stage. The results are shown in Table 22.

The color reversion was also tested by placing the above D2 sample in an oven at 105 ° C for 1 hour. Luminance and L* (whiteness), a* (red to green), and b* (blue to yellow) values were measured before and after the recoloring process by Hunterlab MiniScan according to the manufacturer's protocol. The results are shown in Table 23 below. A positive b value indicates a yellower color. Therefore, higher b values are not desirable in most paper and pulp applications. The fade values reported below represent the difference k/s between before and after aging, where k = absorption coefficient and s = scattering coefficient, ie, fade value = 100 {(k/s) _{after aging} - ( k/s) _{before aging} . See, for example, HWGiertz, Svensk Papperstid, 48(13), 317 (1945).

Southern pine pulp having the same initial capillary CED viscosity was collected from the D2 stage of the same bleaching apparatus described above and treated with hydrogen peroxide and Fe ^{+ 2} as described above. 1.5% hydrogen peroxide (based on dry pulp weight) and 150 ppm Fe ^{+2 were added} .

The properties of this treated pulp are shown in Table 24.

The color reversion of the P* pulp was tested as described above. The results are shown in Table 25 below.

As can be seen from the above data, the acidic catalytic peroxide treatment in the fourth stage of the 5-stage bleaching apparatus results in beneficial brightness properties compared to the treatment after the final stage of the 5-stage bleaching apparatus. In the fourth stage of processing, any loss of brightness from this processing stage can be Compensated by the final D2 bleaching stage, still obtaining high brightness pulp. In the case of post-bleaching treatment, the brightness was significantly lost by 3.4 points and was not compensable. After accelerating the color reversion process, the latter case still has a significantly lower brightness.

Example 23 Strength Data

The strength of the fluff pulp produced from the modified cellulose having a viscosity of 5.1 mPa ‧ in the present disclosure was compared with a conventional fluff pulp having a viscosity of 15.4 mPa ‧ . The results are shown in Table 26 below.

Example 24 Derivatization of Modified Cellulose

The ULDP sample from Example 21 was acid hydrolyzed using 0.05 M HCl at 5% consistency and 122 °C for 3 hours. The average molecular weight or degree of polymerization of the initial pulp, ULDP and acid hydrolyzed ULDP from the D1 stage was tested by the following method.

Three pulp samples were milled through a 20 mesh screen. A sample of cellulose (15 mg) was placed in a separate test tube of a micro stir bar and dried overnight under vacuum at 40 °C. The test tube is then capped using a rubber septum. Anhydrous pyridine (4.00 mL) and phenyl isocyanate (0.50 mL) were added sequentially via a syringe. The test tube was placed in a 70 ° C oil bath and stirred for 48 h. Methanol (1.00 mL) was added to quench any remaining phenyl isocyanate. The contents of each test tube were then added dropwise to a 7:3 methanol/water mixture (100 mL) to promote precipitation of the derivatized cellulose. The solid was collected by filtration and then washed with methanol/water (1×50 mL) then water (2×50 mL). The resulting cellulose was then dried overnight under vacuum at 40 °C. Prior to GPC analysis, the derivatized cellulose was dissolved in THF (1 mg/mL), filtered through a 0.45 [mu]m filter, and placed in a 2 mL autosampler vial. The obtained DPw and DPn (number average degree of polymerization) are reported in Table 27 below.

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

Example 25

Leaf River ULDP fibers and standard softwood fibers were made into handsheets by slurrying the fibers to a pH of about 5.5, and then adding glyoxylated polypropylene decylamine from Kemira Chemicals as a temporary wet strength agent. . The fibers are then formed, pressed into a sheet and dried. Sheet properties are measured by known methods. The results are reported in Table 28 below.

As can be seen in Table 28 above, the ULDP of the present disclosure can be used to produce wet pressed paper. As shown in Figure 2, the wet/dry ratio of handsheets formed from ULDP is higher than the wet/dry ratio of comparative sheets only from standard southern softwood.

Example 26 wicking, rewet, and strength data

Various densities (0.15 g/cm ³ , 0.25 g/cm ³ and 0.35 g/cm ³ ) and basis weight (60 gsm,) were obtained from pulp produced using the modified cellulose and 10% bicomponent fibers of the present disclosure. The synthetic urinary wicking ability of the 150 gsm, 300 gsm) sheet was compared with the self-study sheet made of kraft pulp. With the Materials Testing Service of Kalamazoo, Ml uses its own test equipment and programs to implement the tests. The synthetic wicking ability of the product was tested using a 6.0 cm x 16.0 cm sample and a 600 second lead reading time. The results are shown in Table 29 below.

The retention, thickness variation and wicking height were also determined. The results are shown in Table 30 below:

A rewetting test was also performed on the same sheet. Cutting the sample with 9.0cm × 20.3cm The product was tested for rewet using a tube method and a dose of 10 ml 0.9% saline solution. 120 seconds after the application, the tube was removed and the pre-weighed 6" x 6" sheets of Verigood blotter paper were placed on top and a 3 kpa load was applied for 60 seconds. The results are shown in Table 31 below.

Dry and wet tensile strength and elongation percentage tests were also performed on the same sheet. The tensile strength and elongation percentage of each product were measured in the machine direction using a 5.00 cm gauge length, a 1.3 cm sample width, a 2.5 cm/min crosshead speed, and a 30 kg dynamometer. The results are shown in Tables 32 and 33 below.

Example 27 Wettability, Vertical Wicking, and Horizontal Wicking Data

Wettability, vertical wicking and level of sheets of various densities (0.15 g/cm ³ , 0.30 g/cm ³ and 0.45 g/cm ³ ) obtained from the pulp produced by the modified cellulose of the present disclosure. The wicking is compared to a sheet made from self-learning pulp. With the Materials Testing Service of Kalamazoo, Ml uses its own test equipment and programs to implement the tests.

The wettability characteristics were determined using 10 50 cm ² samples. The results are shown in Tables 34-36 below.

The vertical wicking characteristics were determined using 10 samples and a 600 second probe reading time. The results are shown in Tables 37-38 below.

Horizontal wicking characteristics were determined at 7 ml/sec using a 10 sample, a 600 second probe reading time, and a 30 ml dose. The results are shown in Table 39 below.

Example 28 Multilayer Absorbent Sheet

Five different air-laid multilayer sheets were prepared and cut into 200 4 x 8 inch rectangles. Different groups are labeled as shown in Table 40.

It should be noted that the conventional sheets were treated with TQ-2021 and the modified sheets were treated with TQ-2028, both of which were supplied by Ashland Corporation.

Test the fluid availability, profile and capacity of the product. Fluid acquisition was performed by applying 5 ml of 0.9% saline solution to the sample and then wicking the fluid for 5 minutes. After 5 minutes, it was incubated for 2 more minutes using standard laboratory filter paper. The product has the characteristics shown in Tables 41 and 42.

The synthetic urinary wicking ability of the product was tested using 10 6.0 cm x 16.0 cm samples and a 600 second lead reading time. With the Materials Testing Service of Kalamazoo, Ml uses its own test equipment and programs to implement the tests. The results are shown in Tables 43 and 44 below.

A 9.0 cm x 20.3 cm cut sample was used to test the rewet of the product using a dispensing tube method and a dose of 10 ml 0.9% saline solution using Materials Testing Service. The results are shown in Table 45.

The wetness tensile strength (Materials Testing Service) of each product was measured in the machine direction using 10 samples, a 5.00 cm gauge length, a 1.3 cm sample width, a 2.5 cm/min crosshead speed, and a 30 kg dynamometer. The results are shown in Table 46 below.

The dry tensile strength and elongation percentage of each product were measured in the machine direction using 10 samples, 5.00 cm gauge length, 1.3 cm sample width, 2.5 cm/min crosshead speed and 30 kg dynamometer (Materials Testing Service). ). The results are shown in Table 47 below.

Other inventive embodiments

Although the applicant's presently desired invention is defined in the scope of the accompanying claims, it is to be understood that the invention may be defined by the following examples, which are not necessarily excluded or limited to the embodiments claimed.

A. A fiber derived from bleached softwood or hardwood kraft pulp, wherein the fiber has a 0.5% capillary CED viscosity of about 13 mPa‧s or less, preferably less than about 10 mPa‧s, more preferably less than 8 mPa‧s, More preferably less than about 5 mPa‧s or even more preferably less than about 4 mPa‧s.

B. A fiber derived from bleached softwood kraft pulp, wherein the fiber has an average fiber length of at least about 2 mm, preferably at least about 2.2 mm, such as at least about 2.3 mm or such as at least about 2.4 mm or such as about 2.5 mm, More preferably, it is from about 2 mm to about 3.7 mm, more preferably from about 2.2 mm to about 3.7 mm.

C. A fiber derived from bleached hardwood kraft pulp, 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 mm or at about Between 0.75 mm and about 1.25 mm.

D. A fiber derived from bleached softwood kraft pulp, wherein the fiber has a capillary CED viscosity of about 13 mPa ‧ s or less, an average fiber length of at least about 2 mm, and an ISO between about 85 and about 95 brightness.

The fiber of any one of embodiments A to D, wherein the viscosity is between about 3.0 Between mPa‧s and about 13 mPa‧s, for example about 4.5 mPa‧s to about 13 mPa‧s, preferably about 7 mPa‧s to about 13 mPa‧s or, for example, about 3.0 mPa‧s to about 7 mPa‧s, preferably The ground is about 3.0 mPa‧s to about 5.5 mPa‧s.

F. The fiber of any of embodiments A to D, wherein the viscosity is less than about 7 mPa ‧ s.

G. The fiber of any of embodiments A to D, wherein the viscosity is at least about 3.5 mPa ‧ s.

H. The fiber of any of embodiments A to D, wherein the viscosity is less than about 4.5 mPa ‧ s.

I. The fiber of any of embodiments A to D, wherein the viscosity is at least about 5.5 mPa‧s

J. The fiber of embodiment E, wherein the viscosity is no greater than about 6 mPa ‧ s.

K. The fiber of any of the preceding embodiments, wherein the viscosity is less than about 13 mPa‧s.

L. The fiber of any of embodiments A to B and D to K, wherein the average fiber length is at least about 2.2 mm.

M. The fiber of any of embodiments A to B and D to L, wherein the average fiber length is no greater than about 3.7 mm.

N. The fiber of any of embodiments A to M, wherein the fiber has an S10 caustic solubility of between about 16% to about 30%, preferably between about 16% and about 20%.

O. The fiber of any of embodiments A to M, wherein the fiber has an S10 caustic solubility of between about 14% and about 16%.

P. The fiber of any one of embodiments A to O, wherein the fiber has from about 14% to about 22%, preferably from about 14% to about 18%, more preferably from about 14% to about 16% S18 caustic solubility between.

The fiber of any of embodiments A to P, wherein the fiber has an S18 caustic solubility of between about 14% and about 16%.

R. The fiber of any of embodiments A to Q, wherein the fiber has a ΔR of about 2.9 or greater.

The fiber of any one of embodiments A to Q, wherein the fiber has about 3.0 or Larger, preferably ΔR of about 6.0 or greater.

The fiber of any one of embodiments A to S, wherein the fiber has a mass 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, more preferably about 3 meq/ A carboxyl group content of from 100 g to about 6 meq/100 g.

U. The fiber of any of embodiments A to S, wherein the fiber has a carboxyl content of at least about 2 meq/100 g.

V. The fiber of any of embodiments A to S, wherein the fiber has a carboxyl content of at least about 2.5 meq/100 g.

W. The fiber of any of embodiments A to S, wherein the fiber has a carboxyl content of at least about 3 meq/100 g.

The fiber of any one of embodiments A to S, wherein the fiber has a carboxyl content of at least about 3.5 meq/100 g.

Y. The fiber of any of embodiments A to S, wherein the fiber has a carboxyl content of at least about 4 meq/100 g.

The fiber of any of embodiments A to S, wherein the fiber has a carboxyl content of at least about 4.5 meq/100 g.

AA. The fiber of any of embodiments A to S, wherein the fiber has a carboxyl content of at least about 5 meq/100 g.

BB. The fiber of any of embodiments A to S, wherein the fiber has a carboxyl content of about 4 meq/100 g.

The fiber of any of embodiments A to BB, wherein the fiber has an aldehyde content of between 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. The fiber of any of embodiments A to BB, wherein the fiber has an aldehyde content of at least about 1.5 meq/100 g.

EE.

FF. The fiber of any of embodiments A to BB, wherein the fiber has an aldehyde content of at least about 2.0 meq/100 g.

GG. The fiber of any of embodiments A to BB, wherein the fiber has an aldehyde content of at least about 2.5 meq/100 g.

HH. The fiber of any one of embodiments A to BB, wherein the fiber has an aldehyde content of at least about 3.0 meq/100 g.

The fiber of any of embodiments A to BB, wherein the fiber has an aldehyde content of at least about 3.5 meq/100 g.

J J. The fiber of any of embodiments A to BB, wherein the fiber has an aldehyde content of at least about 4.0 meq/100 g.

KK. The fiber of any of embodiments A to BB, wherein the fiber has an aldehyde content of at least about 5.5 meq/100 g.

LL. The fiber of any of embodiments A to BB, wherein the fiber has an aldehyde content of at least about 5.0 meq/100 g.

MM. The fiber of any one of embodiments A to MM, wherein the fiber has a carbonyl content as determined by a copper value of greater than about 2, preferably greater than about 2.5, more preferably greater than about 3, or as The carbonyl content as determined by a copper value of 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 having a copper value of from about 1 to about 4 The carbonyl content was determined.

NN. The fiber of any of embodiments A to NN, wherein the carbonyl content is between about 2 and about 3.

00. The fiber of any one of embodiments A to NN, wherein the fiber has a carbonyl content as determined by a copper value of about 3 or greater.

The fiber of any one of embodiments A to NN, wherein the fiber has a ratio of total carbonyl to aldehyde content of between about 0.9 and about 1.6.

The fiber of any one of embodiments A to NN, wherein the total carbonyl group has an aldehyde content The ratio is between about 0.8 and about 1.0.

The fiber of any of the preceding embodiments, wherein the fiber has a Canadian standard freeness of at least about 690 mls, preferably at least about 700 mls, more preferably at least about 710 mls, or such as at least about 720 mls or about 730 mls ("free degree").

The fiber of any of the preceding embodiments, wherein the fiber has a freeness of at least about 710 mls.

TT. The fiber of any of the preceding embodiments, wherein the fiber has a freeness of at least about 720 mls.

UU. The fiber of any of the preceding embodiments, wherein the fiber has a freeness of at least about 730 mls.

The fiber of any of the preceding embodiments, wherein the fiber has a freeness of no greater than about 760 mls.

WW. The fiber of any one of embodiments A to W, wherein the fiber has a fiber strength as measured by a wet zero break length of between about 4 km and about 10 km.

XX. The fiber of any of embodiments A to W, wherein the fiber has a fiber strength of between about 5 km and about 8 km.

YY. The fiber of any one of embodiments A to W, wherein the fiber has a fiber strength as measured by a wet zero break length of at least about 4 km.

ZZ. The fiber of any one of embodiments A to W, wherein the fiber has a fiber strength as measured by a wet zero break length of at least about 5 km.

AAA. The fiber of any one of embodiments A to W, wherein the fiber has a fiber strength as measured by a wet zero break length of at least about 6 km.

The fiber of any one of embodiments A to W, wherein the fiber has a fiber strength as measured by a wet zero break length of at least about 7 km.

The fiber of any one of embodiments A to W, wherein the fiber has a fiber strength as measured by a wet zero break length of at least about 8 km.

DDD. The fiber of any one of embodiments A to W, wherein the fiber has a fiber strength measured by a wet zero break length of between about 5 km and about 7 km.

The fiber of any one of embodiments A through W, wherein the fiber has a fiber strength measured by a wet zero break length of between about 6 km and about 7 km.

FFF. The fiber of any of the preceding embodiments, wherein the ISO brightness is between about 85 and about 92, preferably between about 86 and about 90, more preferably between about 87 and about 90, or between about 88 and about 90 ISO. between.

The fiber of any one of the preceding embodiments, wherein the ISO brightness is at least about 85, preferably at least about 86, more preferably at least about 87, especially at least about 88, and even more especially at least about 89 or about 90 ISO. .

HHH. The fiber of any of embodiments A to FFF, wherein the ISO brightness is at least about 87.

The fiber of any of embodiments A to FFF, wherein the ISO brightness is at least about 88.

JJJ. The fiber of any of embodiments A to FFF, wherein the ISO brightness is at least about 89.

KKK. The fiber of any of embodiments A to FFF, wherein the ISO brightness is at least about 90.

The fiber of any of the preceding embodiments, wherein the fiber has substantially the same length as a standard kraft fiber.

MMM. A fiber according to any one of embodiments A to S and SS to MMM having a carboxyl group content higher than that of a standard kraft fiber.

NNN. The fiber of any of embodiments A to S and SS to NNN having an aldehyde content higher than a standard kraft fiber.

The fibers of Examples A through S and SS to MMM having a total aldehyde to carboxyl group ratio of greater than about 0.3, preferably greater than about 0.5, more preferably greater than about 1.4, or such as at least Between 0.3 and about 0.5 or between about 0.5 and about 1 or between about 1 and about 1.5.

PPP. The fiber of any of the preceding embodiments having a kink index that is higher than a standard kraft fiber, such as a kink index of from about 1.3 to about 2.3, preferably from about 1.7 to about 2.3, more preferably. Between 1.8 and about 2.3 or between about 2.0 and about 2.3.

The fiber of any of the preceding embodiments having a length weighted crimp index of between about 0.11 to about 0.2, preferably between about 0.15 and about 0.2.

The fiber of any of the preceding embodiments having a crystallinity index lower than that of a standard kraft fiber, such as a crystallinity index reduced by from about 5% to about 20%, preferably about 10%, relative to a standard kraft fiber. Up to about 20%, more preferably from 15% to 20% relative to standard kraft fiber.

The fiber of any one of the preceding embodiments, wherein the R10 value is between about 65% and about 85%, preferably between about 70% and about 85%, more preferably between about 75% and about 85%. .

The fiber of any of the above embodiments, wherein the R18 value is between about 75% and about 90%, preferably between about 80% and about 90%, more preferably between about 80% and about 87%.

UUU. The fiber of any of the preceding embodiments, wherein the fiber has odor control properties.

The fiber of any of the preceding embodiments, wherein the fiber has a reduced atmospheric ammonia concentration of at least 40%, preferably at least about 50%, more preferably at least about 60%, more specifically than standard kraft fiber. It is at least about 70% or more at least about 75%, more particularly at least about 80% or more about 90%.

WWW. The fiber of any of the preceding embodiments, wherein the fiber absorbs from about 5 ppm ammonia per gram of fiber to about 10 ppm ammonia per gram of fiber, preferably from about 7 ppm ammonia per gram of fiber to about 10 ppm of ammonia per gram of fiber, more preferably About 8 ppm ammonia per gram of fiber to about 10 ppm ammonia per gram of fiber.

XXX. The fiber of any of the preceding embodiments, wherein the fiber has a MEM eluting cytotoxicity test value of less than 2, preferably less than about 1.5, more preferably less than about 1.

YYY. The fiber of any of the above embodiments, wherein the copper value is less than 2, preferably The ground is 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 to YYY having a Kappa number of 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, such as 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, more preferably from about 0.2 to about 0.5.

A AAA. The fiber of any of the preceding embodiments having substantially the same hemicellulose content as a standard kraft fiber, for example between about 16% and about 18% of the fiber-based softwood fiber, or The fiber-based hardwood fibers are between about 18% and about 25%.

BBBB. The fiber of any of the preceding embodiments, wherein the fiber exhibits antimicrobial and/or antiviral activity.

The fiber of any one of embodiments B to C or L to CCCC, wherein the DP is between about 350 to about 1860, such as from about 710 to about 1860, preferably from about 350 to about 910, or such as about 1160 to Between 1860.

DDDD. The fiber of any one of embodiments B to C or L to CCCC, wherein the DP 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. The fiber of any of the preceding embodiments, wherein the fiber is more compressible and/or embossable than standard kraft fiber.

FFFF. A fiber according to embodiments A to OO wherein the fiber is compressible to at least about 0.210 g/cc, preferably at least about 0.220 g/cc, more preferably at least about 0.230 g/cc, especially at least about 0.240 g/ The density of cc.

GGGG. The fiber of any of embodiments A to OO, wherein the fiber is compressible to a density greater than about 8% of the density of the standard kraft fiber, particularly above the density of the standard kraft fiber of between about 8% and about 16%, Preferably from about 8% to about 10% or from about 12% to about 16% higher, more preferably from about 13% to about 16% higher, more preferably from about 14% to about 16% higher, in particular From about 15% to about 16% higher.

A number of embodiments have been described herein. However, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims (20)

A diaper, incontinence device or other urine absorbing product comprising: oxidized kraft fiber produced by bleaching a cellulose kraft pulp using a multi-stage bleaching process; and during at least one stage of the multi-stage bleaching process The kraft pulp is oxidized under acidic conditions using a peroxide and a catalyst, wherein the multi-stage bleaching process includes at least one chlorine bleaching stage after the oxidation stage, and wherein the urine absorbing product is vertically wicked, horizontally wicked or There is at least a 10% improvement in 45 degree wicking. A urine absorbing product according to claim 1 which has an improvement of at least 15% in vertical wicking, horizontal wicking or 45 degree wicking. A urine absorbing product according to claim 1 which has an improvement of at least 20% in vertical wicking, horizontal wicking or 45 degree wicking. A urine absorbing product according to claim 1, wherein the modified kraft fiber is treated with a surfactant. The urine absorbing product of claim 1, wherein the product comprises a plurality of absorbent fibrous layers. The urine absorbing product of claim 1, wherein at least one of the layers comprises oxidized kraft fiber treated with a surfactant. A urine absorbing product according to claim 5, wherein at least two of the layers comprise oxidized kraft fiber. A urine absorbing product according to claim 5, wherein at least one oxidized kraft fiber layer is treated with a surfactant. A urine absorbing product according to claim 7 wherein at least two oxidized kraft fiber layers are treated with a surfactant. The urine absorbing product of claim 1, wherein the urine absorbing device has a density of from 0.1 g/cm ³ to about 0.45 g/cm ³ . The urine absorbing product of claim 10, wherein the density is at least about 0.15 g/cm ³ . The urine absorbing product of claim 10, wherein the density is at least about 0.25 g/cm ³ . The urine absorbing product of claim 10, wherein the density is at least about 0.35 g/cm ³ . The urine absorbing product of claim 12, wherein the product has an increased absorption rate and capacity over a comparable product made using only standard kraft fiber. The urine absorbing product of claim 12, wherein the product has improved dimensional stability over comparable products made using only standard kraft fiber. A urine absorbing product according to claim 5, wherein at least the top layer contains oxidized fibers. A urine absorbing product according to claim 5, wherein at least the bottom layer comprises oxidized fibers. The urine absorbing product of claim 17, wherein at least the top layer and the bottom layer comprise oxidized fibers. The urine absorbing product of claim 1, wherein the retention of the product is improved as the basis weight and density of the oxidized fiber are increased. The urine absorbing product of claim 19, wherein the basis weight of the fibers in the product is at least about 150 gms.