TWI620847B - Urine absorbing product - Google Patents

Abstract

The invention provides a urine absorption device with modified kraft pulp fibers having unique properties. The kraft fiber is produced by a method having at least one acidic iron-catalyzed peroxide treatment process. The at least one acidic iron-catalyzed peroxide treatment process can be incorporated into at least one stage of a multi-stage bleaching process. Products can be diapers, incontinence products and other urine absorption devices.

Description

Urine absorption products

This application is a partial continuation application of US application No. 13 / 314,493 filed on December 8, 2011, and US application No. 13 / 314,493 is US application No. 13 of filed on November 23, 2011 / 322,419 continued application, US Application No. 13 / 322,419 is the national phase of PCT International Application No. PCT / US2010 / 036763 filed under 35 USC § 371 since May 28, 2010, and this The application claims the priority and rights of the application date of US Provisional Application No. 61 / 182,000 filed on May 28, 2009. The subject matter of all cases is incorporated by reference.

This disclosure relates to the chemical modification of cellulose fibers. More specifically, the present disclosure relates to chemically modified cellulose fibers derived from bleached kraft pulp, which exhibit a unique set of properties, thereby improving its performance and making it available for use with standard cellulose fibers derived from kraft pulp So far it has been limited to expensive fiber applications (eg cotton or high alpha cellulose sulfite pulp). Specifically, chemically modified bleached kraft fiber may exhibit one or more of the following beneficial properties including, but not limited to: improved odor control, improved compressibility, and / or improved brightness. Chemically modified bleached kraft fiber can exhibit one or more of these beneficial properties while also maintaining one or more other characteristics of non-chemically modified bleached kraft fiber (eg, maintaining fiber length and / or freeness).

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

This disclosure also pertains to methods for producing the improved fibers described. This disclosure partially provides a method for simultaneously increasing the carboxylic acid and aldehyde functionality of kraft fiber. Catalytic oxidation treatment of the fibers described. In some embodiments, iron or copper is used to oxidize the fiber and then further bleached to provide a fiber with beneficial brightness characteristics (eg, brightness comparable to standard bleached fibers). In addition, at least one process is disclosed that can provide the above-mentioned improved beneficial characteristics without introducing cost-increasing steps for post-treatment of bleached fibers. In this less costly embodiment, the fibers can be processed in a single stage of the kraft paper process (eg, kraft paper bleaching process). Another embodiment relates to a five-stage bleaching process that includes the sequence D ₀ E1D1E2D2, where the fourth stage (E2) includes catalytic oxidation treatment.

Finally, the present disclosure relates to consumer products, cellulose derivatives (including cellulose ethers and esters), and microcrystalline cellulose, which are 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. The source of cellulose and the conditions of cellulose treatment generally determine the characteristics of the cellulose fiber, and thus the suitability of the fiber for certain end applications. There is a need for cellulose fibers that can be processed relatively inexpensively but have a high degree of versatility so that they can be used in various applications.

Cellulose is usually stored in the form of polymer chains containing hundreds to tens of thousands of glucose units in. Various methods of oxidizing cellulose are known. In the oxidation of cellulose, the hydroxyl group of the glycoside of the cellulose chain can be converted into, for example, a carbonyl group (such as an aldehyde group or a carboxylic acid group). Depending on the oxidation method and conditions used, the type, degree and location of carbonyl modification may vary. It is known that certain oxidizing conditions can degrade the cellulose chain itself, for example, by cleaving the glycosidic ring in the cellulose chain, thereby depolymerizing. In most cases, depolymerized cellulose not only has a reduced viscosity, but also has a shorter fiber length than the starting cellulose material. When cellulose degrades (eg, by depolymerization and / or significantly reducing fiber length and / or fiber strength), it may be difficult to handle and / or may not be suitable for many downstream applications. There is still a need for cellulose fiber modification methods that can improve the functionality of carboxylic acids and aldehydes. These methods do not extensively degrade cellulose fibers. This disclosure provides a unique solution to one or more of these defects.

Various attempts have been made to oxidize cellulose to provide carboxylic acid and aldehyde functionality to the cellulose chain without degrading cellulose fibers. In traditional cellulose oxidation methods, when aldehyde groups are present on cellulose, it may be difficult to control or limit the degradation of cellulose. Previous attempts to solve these problems have included the use of multi-step oxidation processes (such as targeted modification of certain carbonyl groups in one step and oxidation of other hydroxyl groups in another step) and / or provision of mediators and / or protective agents, both of which can Give the cellulose oxidation process additional costs and by-products. Therefore, there is a need for a cellulose-modifying method that is cost-effective and / or can be implemented in a single step of the process (eg, kraft paper process).

This disclosure provides a novel method with significant improvements over the methods tried in the prior art. Generally, in the prior art, the oxidation of cellulose kraft fiber is carried out after the bleaching process. Surprisingly, the inventors have discovered that the existing stage of the bleaching sequence (particularly the fourth stage of the 5-stage bleaching sequence) can be used to oxidize cellulose fibers. In addition, surprisingly, the inventors have found that metal catalysts (especially iron catalysts) can be used in the bleaching sequence to achieve this oxidation without interfering with the final product, because (for example) the catalyst does not Remain bound to cellulose so that at least some residual iron is removed earlier than expected based on industry knowledge before the end of the bleaching sequence. In addition, unexpectedly, the inventors have discovered that these methods can be implemented without substantially degrading the fiber.

It is known in the art that metals and peroxides and / or peracids can be used to oxidize cellulose 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), pages 180-184. Metals and peroxides (such as Fenton's reagents) are relatively inexpensive oxidants, making them suitable for large-scale applications to some extent (such as kraft paper processes). In the case of Fenton's reagent, this oxidation method is known to degrade cellulose under acidic conditions. Therefore, it is expected that Fenton's reagent cannot be used in the kraft paper process under acidic conditions and will extensively degrade fibers, for example, accompanied by fiber length loss. To prevent cellulose degradation, Fenton's reagent is usually used under alkaline conditions, in which Fenton reaction is significantly inhibited. However, there are other disadvantages when using Fenton's reagent under alkaline conditions. For example, cellulose may still degrade or discolor. In kraft pulp processing, cellulose fibers are usually bleached in a multi-stage sequence, which usually includes strong acid and strong alkaline bleaching steps, wherein at least one alkaline step is included at or near the end of the bleaching sequence. Therefore, contrary to what is known in the industry, it is quite surprising that using iron to oxidize fibers in the acidic stage of the kraft paper bleaching process results in fibers with enhanced chemical properties but no physical degradation or discoloration.

Therefore, a low cost and / or single-step oxidation is required, which can impart aldehyde and carboxylic acid functionality to cellulose fibers (eg, fibers derived from kraft pulp) and does not extensively degrade cellulose and / or render cellulose unsuitable Many downstream applications. In addition, there is still a need to impart high levels of carbonyl groups to cellulose fibers, such as carboxylic acid, ketone, and aldehyde groups. For example, unlike using Fenton's reagent at an alkaline pH, it is desirable to use an oxidizing agent under conditions that do not inhibit the oxidation reaction to, for example, impart a high content of carbonyl groups. The present inventor has overcome many difficulties of the prior art, thereby providing a method to meet these needs.

In addition to difficulties in controlling the chemical structure of cellulose oxidation products and the degradation of their products, known oxidation methods can affect other properties, including chemical and physical properties and / or impurities in the final product. For example, the oxidation method can affect the crystallinity, hemicellulose content Amount, color and / or impurity content in the final product. Finally, oxidation methods can affect the ability to process cellulose products for industrial or other applications.

The pulp is usually bleached by selectively increasing the whiteness or brightness of the pulp (usually by removing lignin and other impurities), which does not negatively affect the physical properties. The bleaching of chemical pulp (eg kraft pulp) usually requires several different bleaching stages to achieve the desired brightness with good selectivity. In general, the bleaching sequence employs stages carried out at alternating pH ranges. This alteration helps to remove impurities generated in the bleaching sequence, for example, by dissolving the lignin decomposition products. Therefore, in general, it is expected that the use of an acid stage series (eg, a sequence of three acid stages) in a bleaching sequence will not provide the same brightness as alternating acid / alkaline stages (eg, acid-alkaline-acid). For example, a typical DEDED sequence produces a product that is brighter than the DEDAD sequence (where A refers to acid treatment). Therefore, a sequence that does not have an intermediate alkaline stage still produces products with the same brightness, which cannot be expected by those skilled in the art.

Generally, although it is known that certain bleaching sequences may have advantages over other sequences in the kraft paper process, the reason behind any advantage is not fully understood. As far as oxidation is concerned, there is no research demonstrating any oxidation priority in a specific stage of a multi-stage sequence or any knowledge about fiber properties that can be affected by post-oxidation stages / treatments. For example, the prior art does not reveal any prioritization of late stage oxidation over early stage oxidation. In some embodiments, the present disclosure provides a method that is uniquely implemented in a specific stage (eg, a later stage of the bleaching process), which benefits the kraft paper process and results in fibers with a unique set of physical and chemical properties.

In addition, with regard to the brightness in the kraft paper bleaching process, it is known that metals (specifically, transition metals naturally present in the starting material of the pulp) are not conducive to the brightness of the product. Therefore, the bleaching sequence is usually aimed at removing certain transition metals from the final product to achieve the target brightness. For example, chelating agents 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 usually do not add any metals to the bleaching sequence, which will increase the difficulty of achieving brighter products.

In the case of iron, in addition, the addition of this material to the pulp causes significant discoloration, which is similar to the discoloration that exists when, for example, burning paper. So far it is believed that, like the fading of burning paper, this fading is irreversible. Therefore, it is expected that after the wood pulp added with iron is faded, the pulp will permanently lose its brightness, and the brightness cannot be restored by using additional bleaching.

Therefore, although iron or copper and peroxides are known to oxidize cellulose inexpensively, they have not been used in pulp bleaching processes in a way that achieves a comparable brightness to the standard sequence that does not employ iron or copper oxidation steps. Generally, avoid using it in the pulp bleaching process. Surprisingly, the inventors have overcome these difficulties, and in some embodiments provide a novel method for cheaply oxidizing cellulose using iron or copper in the pulp bleaching process. In some embodiments, the method disclosed herein results in products with very surprising characteristics that are contrary to the characteristics predicted by them based on the teachings of the prior art. Therefore, the method of the present disclosure can provide products that are superior to those of the prior art and can be produced more cost-effectively.

For example, it is generally understood in the industry that metals (such as iron) are sufficiently bound to cellulose and cannot be removed by normal washing. Generally, 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 cellulose products can have several disadvantages, especially in pulp and paper applications. For example, iron may cause discoloration of the final product and / or may not be suitable for applications where the final product is in contact with the skin (such as diapers and wound dressings). Therefore, the use of iron in the kraft paper bleaching process is expected to produce many disadvantages.

To date, the oxidation treatment of kraft fiber used to improve functionality is generally limited to the oxidation treatment after bleaching the fiber. In addition, known processes that give fibers greater aldehyde functionality also result in a loss of fiber brightness or quality. In addition, the known process of reinforcing aldehyde functionality also results in a loss of carboxylic acid functionality. The method of the present disclosure does not create one or more of these disadvantages.

Kraft fibers produced by chemical kraft pulping methods provide a cheap source of cellulose fibers (usually maintaining fiber length through pulping), and generally provide end products 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) due to the chemical structure of cellulose derived from standard kraft pulping and bleaching. In general, standard kraft fiber contains excessive residual hemicellulose and other naturally occurring materials that can interfere with the 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 rigidity and roughness of kraft fiber may require layering or the addition of different types of materials (such as cotton) in applications that require contact with human skin (such as diapers, hygiene products, and paper towels). Therefore, it may be desirable to provide cellulose fibers with better flexibility and / or flexibility to reduce the need to use other materials, such as in multilayer products.

Applications involving absorption of body waste and / or body fluids (e.g. diapers, adult incontinence products, wound dressings, sanitary napkins and / or cotton balls) are usually exposed to ammonia present in body waste and / or to the body Ammonia produced by bacteria associated with waste and / or body fluids. In such applications, it may be desirable to use cellulose fibers that not only provide volume and absorbency, but also have odor reduction and / or antibacterial properties (eg, can be reduced from nitrogen-containing compounds (eg, ammonia (NH ₃ )) The smell). To date, the modification of kraft fiber by oxidation to improve its odor control ability has always undesirably reduced brightness. There is a need for cheap modified kraft fiber that exhibits good absorption characteristics and / or odor control capabilities 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 design requires lower fiber weight and can result in loss of product integrity (if the fiber used is too short). Chemical modification of kraft fiber can result in loss of fiber length, making it unacceptable for use in certain types of products (eg, ultra-thin products). More specifically, kraft fiber treated to improve aldehyde functionality (which is related to improved odor control) can lose fiber length during chemical modification, making it unsuitable for ultra-thin product designs. Need to exhibit compressibility without losing fiber length to make it uniquely suitable for cheap fibers with ultra-thin design (i.e. based on the amount of fibers that can be compressed into a smaller space while maintaining product integrity at a lower fiber weight Good absorption products).

Traditionally, cellulose sources that can be used to produce absorbent products or paper towels cannot also be used to produce downstream cellulose derivatives, such as cellulose ethers and cellulose esters. The production of low-viscosity cellulose derivatives from high-viscosity cellulose raw materials (such as standard kraft fiber) requires additional manufacturing steps, which will increase a large amount of cost while giving undesirable by-products and reducing the overall quality of the cellulose derivative. Cotton linters and high alpha cellulose content sulfite pulps (which usually have a high degree of polymerization) are commonly used to make cellulose derivatives, such as cellulose ethers and esters. However, the production of lint and sulfite fibers with high polymerization and / or viscosity is relatively expensive due to the following factors: starting material cost (in the case of cotton), high energy for pulping and bleaching, chemical and environmental costs (In the case of sulfite pulp) and the extensive purification process required (in both cases). In addition to high costs, the supply of sulfite pulp that can be used in the market has decreased. Therefore, these fibers are extremely expensive and have limited applicability in pulp and paper applications. For example, higher DP or higher viscosity pulp may be required. For cellulose derivative manufacturers, such pulp constitutes the majority of their overall manufacturing costs. Therefore, there is a need for low-cost fibers that can be used to produce cellulose derivatives, such as modified kraft fiber.

There is also a need for cheap cellulose materials that can be used to make microcrystalline cellulose. Microcrystalline cellulose is widely used in food, medicine, cosmetics and industrial applications, and is a purified crystalline form of partially depolymerized cellulose. To date, the use of kraft fiber has been restricted in the production of microcrystalline cellulose without adding extensive post-bleaching treatment steps. Microcrystalline cellulose produces a cellulose starting material that usually requires a high degree of purification, which is acid hydrolyzed to remove the amorphous segments of the cellulose chain. See U.S. Patent No. 2,978,446 issued to Battista et al. And U.S. Patent No. 5,346,589 issued to Braunstein et al. The low degree of polymerization of the chain after removing the amorphous segment of cellulose (called "stable DP") is usually used as the starting point for the production of microcrystalline cellulose and its value depends mainly on the source and treatment of cellulose fibers. The dissolution of non-crystalline sections from standard kraft fiber usually degrades the fiber to the point that it is not suitable for most applications. This is caused by at least one of the following reasons: 1) residual impurities; 2) lack of sufficient length Crystal Section; or 3) which results in cellulose fibers with an excessively high degree of polymerization (usually in the range of 200 to 400), making them useful for producing microcrystalline cellulose. For example, kraft fiber with good purity and / or lower stable DP value is more desirable because the drawn fiber can provide greater versatility in the production and application of microcrystalline cellulose.

In this disclosure, fibers with one or more of the described properties can be produced simply by modifying typical kraft pulping and bleaching processes. The fibers of this disclosure overcome many of the limitations associated with the known modified kraft fiber mentioned 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

This disclosure provides a novel method of processing cellulose fibers. In some embodiments, the present disclosure provides a method of modifying cellulose fibers, which includes providing cellulose fibers and oxidizing the cellulose fibers. As used herein, "oxidized (oxidized)" and "catalytically oxidized (catalytic oxidation)" should be understood to be used interchangeably and refer to the use of at least one of at least one catalytic amount of iron or copper And at least one peroxide (for example, hydrogen peroxide) treats the cellulose fiber, so that at least some hydroxyl groups of the cellulose fiber are oxidized. The phrase "iron or copper" and similarly "iron (or copper)" mean "iron or copper or a combination thereof". In some embodiments, the oxidation includes simultaneously increasing the carboxylic acid and aldehyde content of the cellulose fiber.

The cellulose fibers used in the methods described herein can be derived from softwood fibers, hardwood fibers, and mixtures thereof. In some embodiments, the modified cellulose fiber system is derived from softwood, such as southern pine wood. In some embodiments, the modified cellulose fiber system is derived from hard Wood, for example by tree. In some embodiments, the modified cellulose fiber is derived from a mixture of softwood and hardwood. In yet another embodiment, the modified cellulose fibers are derived from cellulose fibers that have previously been subjected to all or part of the kraft paper process, that is, kraft fiber.

The "cellulose fiber" or "kraft fiber" mentioned in this disclosure can be used interchangeably unless specifically indicated as different or understood by those skilled in the art.

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

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

In at least one embodiment, the method includes providing cellulose fibers, partially bleaching the cellulose fibers, and oxidizing the cellulose fibers. In some embodiments, the oxidation is performed during the bleaching process. In some embodiments, the oxidation is performed after the bleaching process.

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

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

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

As discussed above, according to the present disclosure, the oxidation of cellulose fibers involves treating the cellulose fibers with at least a catalytic amount of iron or copper and hydrogen peroxide. In at least one embodiment, the method includes oxidizing cellulose 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 (eg ferrous sulfate heptahydrate), ferrous chloride, ferrous ammonium sulfate, ferric chloride, ferric ammonium sulfate Or citric acid Ferric ammonium.

In some embodiments, the method includes oxidizing cellulose 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 cellulose fibers using a combination of copper and iron and hydrogen peroxide.

In some embodiments, the present disclosure provides a method of treating cellulose fibers, which includes providing cellulose fibers, pulping the cellulose fibers, bleaching the cellulose fibers, and oxidizing the cellulose fibers.

In some embodiments, the method further includes performing oxygen delignification on the cellulose fibers. Oxygen delignification can be carried out by any method known to those skilled in the art. For example, the oxygen delignification can be conventional two-stage oxygen delignification. For example, it is known that oxygen delignification of cellulose fibers (such as kraft fiber) can change the carboxylic acid and / or aldehyde content of cellulose fibers during processing. In some embodiments, the method includes performing oxygen delignification on the cellulose fibers before bleaching the cellulose fibers.

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

When the cellulose fibers are oxidized in the bleaching step, the cellulose fibers should not be subjected to substantially alkaline conditions during or after oxidation in the bleaching process. In some embodiments, the method includes oxidizing cellulose fibers at an acidic pH. In some embodiments, the method includes providing cellulose fibers, acidifying the cellulose fibers, and then oxidizing the cellulose fibers at an acidic pH. In some embodiments, the pH is between about 2 to about 6, for example, about 2 to about 5, or 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 Or the filtrate from the acid bleaching stage of the bleaching process (such as the chlorine dioxide (D) stage of the multistage bleaching process) to adjust the pH. For example, cellulose fibers can be acidified by adding 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 from the bleaching step (eg, waste filtrate) is used to acidify the cellulose fibers. In some embodiments, the acid filtrate from the bleaching step does not have high iron content. In at least one embodiment, the cellulose fiber is acidified with the acid filtrate from the D-stage of the multi-stage bleaching process.

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

According to the present disclosure, the multi-stage bleaching sequence may 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 DEDED sequence. In some embodiments, the bleaching sequence is a D ₀ E1D1E2D2 sequence. In some embodiments, the bleaching sequence is a D ₀ (EoP) D1E2D2 sequence. In some embodiments, the bleaching sequence is D ₀ (EO) D1E2D2.

The non-oxidation stage of the multi-stage bleaching sequence can include any conventional stage or be implemented under conventional conditions after the discovered series of stages, provided that no alkaline bleaching step can be present after the oxidation step to be used to produce what is described in this disclosure Modified fiber.

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

In some embodiments, after the oxidation of cellulose fibers, the kappa value (kappa number) has increased. More specifically, based on the expected reduction in materials that react with permanganate reagents, such as lignin, it is generally expected that the Kappa number will decrease during this bleaching stage. However, in the method as described herein, the Kappa number of cellulose fibers can be reduced due to loss of impurities (eg, lignin); however, the Kappa value can be increased due to chemical modification of the fibers. Without wishing to be bound by theory, it is believed that increasing the functionality of the modified cellulose provides additional sites that can react with the permanganate reagent. Therefore, the Kappa value of the modified kraft fiber is higher than that of the standard kraft fiber.

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

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

Advantageously, before bleaching, the cellulose fiber is digested to the target Kappa number. For example, when oxidized cellulose is desired for paper-grade or fluff pulp cellulose, Lo-Solids ^TM can be used to digest cellulose fibers to Kappa before being bleached and oxidized in a two vessel hydraulic digestion tank The value is between about 30 and about 32. Another option is that if oxidized cellulose is desired in cellulose derivative applications (eg in the manufacture of cellulose ethers), the cellulose fibers can be digested to the card before bleaching and oxidizing the cellulose according to the method of the present disclosure The Berber value is between about 20 and about 24. In some embodiments, before bleaching and oxidizing the cellulose fiber, the cellulose fiber is digested and delignified in a conventional two-stage oxygen delignification step. Advantageously, delignification is performed until the target Kappa value is between about 6 and about 8 (when oxidized cellulose is intended for cellulose derivative applications) and the target Kappa value 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 performed under certain conditions until it reaches about 88- 90% final target ISO brightness, for example between about 85% to about 95% or about 88% to about 90%.

The present disclosure also provides a method of treating cellulose fibers, which includes providing cellulose fibers, reducing the DP of cellulose fibers, and maintaining the fiber length of cellulose fibers. In some embodiments, the cellulose fiber is kraft fiber. In some embodiments, the DP of cellulose fibers is reduced during the bleaching process. In some embodiments, the DP of the cellulose fiber 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 stage 4 of the multi-stage bleaching sequence.

Alternatively, the multi-stage bleaching sequence can be changed to provide more stable bleaching conditions before the cellulose fibers are oxidized. In some embodiments, the method includes providing more stable bleaching conditions before the oxidation step. More stable bleaching conditions may allow the use of smaller amounts of iron or copper and / or hydrogen peroxide in the oxidation step to reduce the degree of polymerization and / or viscosity of the cellulose fibers. Therefore, the bleaching sequence conditions can be modified so that the brightness and / or viscosity of the final cellulose product can be further controlled. For example, reducing the amount of peroxides and metals while providing more stable bleaching conditions before oxidation can provide products with lower viscosity and higher brightness than oxidized products produced using the same oxidation conditions but using less stable bleaching . In some embodiments, these 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 cellulose fiber so that it is lower than the crystallinity of the cellulose fiber measured before the oxidation stage. For example, according to the method of the present disclosure, the crystallinity index of cellulose fibers can be reduced by as much as 20% relative to the initial crystallinity index measured before the oxidation stage.

In some embodiments, the method of the present disclosure further includes treating the modified cellulose fiber with at least one caustic or alkaline substance. For example, in at least one embodiment, a method of treating cellulose fibers includes providing the oxidized cellulose fibers of the present disclosure, exposing the oxidized cellulose fibers to an alkaline or caustic substance, and then allowing the cellulose to produce Quality control method. Without being bound by theory, it is believed that the addition of at least one caustic substance to the modified cellulose can yield cellulose fibers with extremely high functionality and extremely low fiber lengths.

It is known that cellulose including increased aldehyde groups may have advantageous properties to improve the wet strength of cellulose fibers. See, for example, US Patent No. 6,319,361 issued to Smith et al. And No. 6,582,559 issued to Thornton et al. Such properties can be beneficial for, for example, absorbent material applications. In some embodiments, the present disclosure provides a method of improving the wet strength of a product, which includes providing the modified cellulose fiber of the present disclosure and adding the modified cellulose fiber of the present disclosure to a product, such as a paper product. For example, the method may include oxidizing cellulose fibers in a bleaching process, further treating the oxidized cellulose fibers with acidic or caustic substances, and adding the treated fibers to the cellulose product.

According to the present disclosure, hydrogen peroxide is added to the cellulose fibers present in the acidic medium in an amount sufficient to achieve the desired degree of oxidation and / or polymerization and / or viscosity of the final cellulose product. For example, based on the dry weight of the pulp, the peroxide may be added in an amount of about 0.1% to about 4% or about 1% to about 3% or about 1% to about 2% or about 2% to about 3%.

Iron or copper is added at least in an amount sufficient to catalyze the oxidation of cellulose and peroxide. For example, iron can be added in an amount between about 25 ppm and about 200 ppm based on the dry weight of kraft pulp. Those skilled in the art can easily 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 cellulose product.

In some embodiments, the method additionally involves adding steam before or after adding 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 before the oxidation step. Those skilled in the art realize that other properties of the modified kraft fiber of the present disclosure can be affected by the amount of iron or copper and hydrogen peroxide and the stability of the bleaching conditions before 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 before 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 cellulose fibers, which includes providing cellulose fibers, reducing the degree of polymerization of cellulose fibers, and maintaining the fiber length of cellulose fibers.

In some embodiments, the oxidized kraft fiber of this disclosure is not refined. Refining oxidized kraft fiber can have a negative effect on its fiber length and integrity. For example, refining fibers can cause fiber splitting.

In some embodiments, each stage of the 5-stage bleaching process includes 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 the D1 stage scrubber, the iron source is also added to the kraft pulp on the D1 stage scrubber, the iron source (or copper source) is followed by the mixer or pump before the E2 stage column Peroxide is added at the point of addition, the kraft pulp is reacted in the E2 tower and washed on the E2 scrubber, and steam may be added in the steam mixer before the E2 tower as appropriate.

In some embodiments, iron (or copper) may be added until the end of the D1 phase, or iron (or copper) may also be added at the beginning of the E2 phase, provided that it is first (that is, before adding iron) in the D1 phase Acidified pulp. Optionally, add steam before or after adding the peroxide.

In an exemplary embodiment, a method of preparing low viscosity modified cellulose fibers may involve bleaching kraft pulp in a multi-stage bleaching process and at or near the final stage of the multi-stage bleaching process (e.g. in a multi-stage bleaching process The fourth stage, for example in the fourth stage of the five-stage bleaching process, is to reduce the pulp DP 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 appropriate application of iron or copper and hydrogen peroxide, as further explained in the example section. In some embodiments, a fiber suitable for producing low DP fibers (ie, fibers with a DPw between about 1180 to about 1830 or a 0.5% capillary CED viscosity between about 7 mPa‧s to about 13 mPa‧s) The amount and conditions to provide iron or copper and hydrogen peroxide. In some exemplary embodiments, it may be suitable for producing ultra-low DP fibers (ie, DPw between about 700 to about 1180 or 0.5% capillary CED viscosity between about 3.0 mPa‧s to about 7 mPa‧s Fiber) in quantities and conditions to provide iron or copper and hydrogen peroxide.

For example, in some embodiments, treatment with hydrogen peroxide and iron or copper in an acidic medium may 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 added hydrogen peroxide to the kraft pulp.

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

In some embodiments, a method of preparing modified cellulose fibers within the scope of the present disclosure involves reducing DP by treating kraft pulp with hydrogen peroxide in an acidic medium in the presence of iron (or copper), wherein the acidic , Hydrogen peroxide and iron (or copper) treatment are included in the multi-stage bleaching process. In some embodiments, iron, acid, and hydrogen peroxide treatments are incorporated into a single stage of a multi-stage bleaching process. In some embodiments, iron (or copper), acid, and hydrogen peroxide treatments are 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 treatments 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, the pulp processing can occur in a single stage (eg, E2 stage). In some embodiments, each stage of the 5-stage bleaching process includes 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 the D1 stage scrubber, Iron source is also added to the kraft pulp on the D1 stage scrubber. Peroxide sources can be added after the iron source (or copper source) before the E2 stage column mixer or at the point of addition in the pump, which can be added to the E2 column The kraft pulp is reacted and washed on the E2 scrubber, and steam is optionally added in the steam mixer before the E2 tower. In some embodiments, for example, iron (or copper) may be added until the end of the D1 stage, or iron (or copper) may also be added at the beginning of the E2 stage, provided that it is first (that is, before adding iron) In the 1 stage, the pulp is acidified, additional acid may be added as necessary to bring the pH to the range of about 3 to about 5, and the peroxide may be added after iron (or copper). Steam can be added before or after the peroxide is added.

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

According to another example (where cellulose fibers are softwood fibers), the above exemplary 5-stage bleaching process can produce modified cellulose softwood fibers having the following properties: the average fiber length is at least 2.0 mm (eg, between about 2.0 mm to about 3.7mm or about 2.2mm to about 3.7mm), the viscosity is less than 13mPa‧s (for example, the viscosity is about 3.0mPa‧s to less than 13mPa‧s or about 3.0mPa‧s to about 5.5mPa‧s or about 3.0mPa ‧S to about 7mPa‧s or about 7 mPa‧s to less than 13rrPa‧s), and the brightness is at least 85 (for example, between about 85 to about 95).

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

The present disclosure also provides methods for reducing odors (such as odors from body waste, such as urine or blood). In some embodiments, the present disclosure provides a method for controlling odors, which includes providing the modified bleached kraft fiber of the present disclosure, and applying an odorant to the bleached kraft fiber so that Compared with the air volume of the odorant after applying an equivalent amount of odorant, the air volume of the odorant is reduced. In some embodiments, the present disclosure provides a method for controlling odor, which includes inhibiting bacterial odor generation. In some embodiments, the present disclosure provides a method for controlling odor, which includes absorbing an odorant (eg, a nitrogen-containing odorant) on modified kraft fiber. As used herein, "nitrogen-containing odorant" is understood to mean an odorant that includes at least one nitrogen.

In at least one embodiment, a method for reducing odor includes providing the modified cellulose fiber of the present disclosure, and applying an odorant (such as a nitrogen-containing compound (such as ammonia) or a compound capable of generating a nitrogen-containing compound to the modified kraft fiber organism). In some embodiments, the method further includes forming fluff pulp from the modified cellulose fiber before adding the odorant to the modified kraft fiber. In some embodiments, the odorant includes at least one bacteria capable of producing nitrogen-containing compounds. In some embodiments, the odorant includes a nitrogen-containing compound, such as ammonia.

In some embodiments, the method of reducing odor further includes absorbing ammonia in the repaired Decorated on cellulose fibers. In some embodiments, the method of reducing odor further includes inhibiting bacterial ammonia production. In some embodiments, the method of inhibiting bacterial ammonia production includes inhibiting bacterial growth. In some embodiments, the method of inhibiting bacterial ammonia production includes inhibiting bacterial urea synthesis.

In some embodiments, the method of reducing odor includes combining the modified cellulose fiber with at least one other deodorant, and then applying the odorant to the modified cellulose fiber combined with the deodorant.

Exemplary deodorants are known in the industry, and include, for example, odor reducing agents, odor masking agents, biocides, enzymes, and urease inhibitors. For example, the modified cellulose fibers can be combined with at least one deodorant selected from the group consisting of zeolite, activated carbon, diatomaceous earth, cyclodextrin, clay, and chelating agents (e.g. they contain Metal ions such as ions or zinc ions), ion exchange resins, antibacterial or antimicrobial polymers and / or fragrances.

In some embodiments, the modified cellulose fiber is combined with at least one superabsorbent polymer (SAP). In some embodiments, SAP can be a deodorant. Examples of SAPs that can be used in this disclosure include, but are not limited to, Hysorb ^™ sold by BASF, Aqua Keep® sold by Sumitomo, and FAVOR® sold by Evonik.

II. Kraft fiber

This article refers to "standard", "conventional" or "traditional" kraft fiber, kraft paper bleached fiber, kraft paper pulp or kraft paper bleached pulp. The fiber or pulp is usually described as a reference point for defining the improved properties of the present invention. As used herein, these terms are used interchangeably and refer to the target fiber or pulp that has not undergone any oxidation (single or subsequent one or more alkali or acid treatments) has the same composition and is treated in a similar manner (i.e. Treated in standard or conventional way) fiber or pulp. As used herein, the term "modified" means that the fiber is subjected to an oxidation treatment (single or subsequent one or more alkali or acid treatments).

The physical properties (such as fiber length and viscosity) of the modified cellulose fiber mentioned in the specification were measured according to the scheme provided in the example section.

This disclosure provides kraft fiber with low and ultra-low viscosity. Unless otherwise specified, "viscosity" as used herein refers to the 0.5% capillary CED viscosity measured according to TAPPI T230-om99 mentioned in the protocol. The modified kraft fiber of the present invention exhibits unique characteristics indicative of its chemical modification. More specifically, the fiber of the present invention exhibits characteristics similar to those of standard kraft fiber (ie, length and freeness), but also exhibits some extremes that change with the increase in the number of functional groups included in the modified fiber Different characteristics. This modified fiber exhibits unique characteristics when implementing the cited TAPPI test for measuring viscosity. Specifically, the cited TAPPI test uses caustic reagents to treat fibers as part of the test method. As stated, the application of caustic agents to the modified fibers causes the modified fibers to hydrolyze in a manner different from the standard kraft fiber, thereby reporting a viscosity that is generally lower than that of the standard kraft fiber. 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 cited TAPPI method) represents the viscosity of kraft fiber used to calculate the degree of fiber polymerization.

Unless otherwise specified, "DP" as used herein refers to the average weight polymerization (DPw) calculated from the 0.5% capillary CED viscosity measured according to TAPPI T230-om99. For example, see JF Cellucon Conference, The Chemistry and Processing of Wood and Plant Fibrous Materials , page 155, Test Protocol 8, 1994 (Woodhead Publishing Co., Abington Hall, Abinton Cambridge CBI 6AH England, edited by JF Kennedy et al.). "Low DP" means a DP between about 1160 to about 1860 or a viscosity between about 7 mPa‧s to about 13 mPa‧s. "Ultra-low DP" fiber means a DP between about 350 to 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 fiber of the present invention exhibits an artificial degree of polymerization when the DP is calculated via the CED viscosity measured according to TAPPI T230-om99. Specifically, it is believed that the catalytic oxidation treatment of the fibers of the invention does not decompose cellulose to the level indicated by the measured DP To the extent, it mainly has the effect of opening bonds and adding substituents to make cellulose more reactive, rather than cleaving cellulose chains. It is also believed that the CED viscosity test (TAPPI T230-om99, which begins with the addition of caustic reagents) has the effect of cleaving cellulose chains at new reactive sites, resulting in a much higher level than that found in the pre-fiber test Cellulose polymer with a shorter number of sections. This can be confirmed by the fact that the fiber length does not decrease significantly during production.

In some embodiments, the modified cellulose fiber has a DP between about 350 and about 1860. In some embodiments, the DP is between about 710 to about 1860. In some embodiments, the DP is between about 350 to about 910. In some embodiments, the DP is between about 350 to about 1160. In some embodiments, the DP is between about 1160 to 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 cellulose fiber has a viscosity 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 cellulose fiber has 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, when the modified cellulose fiber is a softwood fiber, the modified Cellulose 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 3.2mm, about 3.3mm, about 3.4mm, about 3.5mm, about 3.6mm or about 3.7mm. In some embodiments, the average fiber length is between about 2 mm to about 3.7 mm or about 2.2 mm to about 3.7 mm.

In some embodiments, when the modified cellulose fiber is a hardwood fiber, the modified cellulose fiber has an average fiber length of about 0.75 mm to about 1.25 mm. For example, the average fiber length may 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 standard kraft fiber. In some embodiments, the modified cellulose fiber has 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 about 86 to about 90 or about 87 to about 90 or about 88 to about 90.

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

In some embodiments, the modified cellulose 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 cellulose fibers of the present disclosure can be compressed to a density between about 0.21 g / cc and about 0.24 g / cc. In at least one embodiment, after compression at 20 psi gauge pressure, the modified cellulose fibers of the present disclosure have a density between about 0.21 g / cc and about 0.24 g / cc.

In some embodiments, after compression at about 5 psi gauge pressure, the modified cellulose fibers of the present disclosure have a density between about 0.110 g / cc to about 0.114 g / cc. For example, after compression at about 5 psi gauge pressure, the modified cellulose fibers of the present disclosure may 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 ) Density.

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

In some embodiments, the modified cellulose fibers of the present disclosure can be compressed to a density that is at least about 8% higher than the density of standard kraft fiber. In some embodiments, the density of the modified cellulose fibers of the present disclosure is about 8% to about 16% higher than the density of standard kraft fiber, such as about 10% to about 16% higher or about 12% to about 16% higher Or about 13% to about 16% higher or about 14% to about 16% higher or about 15% to about 16% higher.

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 cellulose fiber has a carboxyl group content between about 2 meq / 100 g and about 9 meq / 100 g. In some embodiments, the carboxyl content is between about 3 meq / 100g and about 8 meq / 100g. In some embodiments, the carboxyl content is about 4meq / 100g. In some embodiments, the carboxyl content is at least about 2 meq / 100g, such as at least about 2.5meq / 100g, such as at least about 3.0meq / 100g, such as at least about 3.5meq / 100g, such as at least about 4.0meq / 100g, such as at least about 4.5 meq / 100g, or for example at least about 5.0meq / 100g.

The modified kraft fiber of this disclosure has increased aldehyde content relative to standard bleached kraft fiber. In some embodiments, the modified kraft fiber has between about 1 The aldehyde content between meq / 100g and 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 cellulose fiber has 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 group ratio is between about 0.3 to about 1.5. In some embodiments, the ratio is between about 0.3 to about 0.5. In some embodiments, the ratio is between about 0.5 to about 1. In some embodiments, the ratio is between about 1 to about 1.5.

In some embodiments, the modified kraft fiber has a higher kink and curl than standard kraft fiber. The modified kraft fiber of the present invention has a kink index in the range of about 1.3 to about 2.3. For example, the knot index may be between about 1.5 to about 2.3 or about 1.7 to about 2.3 or about 1.8 to about 2.3 or about 2.0 to about 2.3. The modified kraft fiber of the present disclosure may have a length-weighted curl index in the range of about 0.11 to about 0.23 (eg, about 0.15 to about 0.2).

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

In some embodiments, the modified cellulose of the present disclosure has an R10 value between about 65% to about 85% (eg, about 70% to about 85% or about 75% to about 85%). In some embodiments, the modified fiber of the present disclosure has an R18 value between about 75% to about 90% (eg, about 80% to about 90%, such as about 80% to about 87%). The contents of R18 and R10 are described in TAPPI 235. R10 represents the residual undissolved material remaining after extracting the pulp with 10% by weight caustic solution, and R18 represents the residual amount of undissolved material remaining after extracting the pulp with 18% caustic solution. Generally, in a 10% caustic solution, hemicellulose and chemically degraded short-chain cellulose are dissolved in the solution and removed. In contrast, usually only half fiber The element is dissolved in 18% caustic solution and removed. Therefore, 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 (such as kink and curl of fibers, increased functionality, and crystallinity of modified kraft fiber), those skilled in the art expect that the modified kraft fiber of the present disclosure has standard kraft fiber Some features not possessed. For example, it is believed that the kraft fiber of the present disclosure may be more flexible than standard kraft fiber, and may stretch and / or bend and / or exhibit elasticity and / or increase wicking. In addition, without being bound by theory, it is expected that the modified kraft fiber may, for example, provide entanglement of fibers in the fluff pulp and fiber / fiber bonding or entanglement of materials applied to the pulp (so that these materials remain relatively within the pulp The physical structure at a fixed spatial position to prevent its dispersion). In addition, it is expected that the modified kraft fiber of the present disclosure is softer than standard kraft fiber at least due to a reduction in crystallinity relative to standard kraft fiber, thereby enhancing its applicability in absorbent product applications such as diaper and bandage applications Sex.

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

In some embodiments, the strength of the modified cellulose fiber (as measured by the wet zero-break length) is between about 4 km to about 10 km (eg, about 5 km to about 8 km). In some embodiments, the fiber strength is at least about 4 km, about 5 km, about 6 km, about 7 km, or about 8 km. In some embodiments, the fiber strength is between about 5 km to about 7 km or about 6 km to 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 menstrual fluid. In some embodiments, the modified kraft fiber absorbs ammonia. In some embodiments In the modified kraft fiber inhibits bacterial odor production, for example, in some embodiments, the modified kraft fiber inhibits bacterial ammonia production.

In at least one embodiment, the modified kraft fiber can absorb odorants (eg, nitrogen-containing odorants, such as ammonia).

As used herein, the term "odorant" should be understood to mean a chemical material having a taste or odor or capable of interacting with olfactory receptors, or an organism (such as bacteria, such as bacteria, such as bacteria that can generate a taste or odor) Urea-producing bacteria).

In some embodiments, the modified kraft fiber reduces the atmospheric ammonia concentration more than the standard bleached kraft fiber reduces atmospheric ammonia. For example, 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 atmospheric ammonia by at least about 40% more than the standard kraft fiber, such as at least about 50% or more than about 60% or about 70% or more than about 75% more than the standard kraft fiber More than about 80% or more than about 90% ammonia.

In some embodiments, after applying 0.12 g of 50% ammonium hydroxide solution to about 9 g of modified cellulose and a 45 minute incubation time, the modified kraft fiber of the present disclosure will have an atmospheric ammonia concentration in a volume of 1.6 L 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 about 5 ppm ammonia / gram fiber to about 10 ppm ammonia / gram fiber. For example, modified cellulose can absorb about 6 ppm ammonia / gram fiber to about 10 ppm ammonia / gram fiber or about 7 ppm ammonia / gram fiber to about 10 ppm ammonia / gram fiber or about 8 ppm ammonia / gram fiber to about 10 ppm ammonia / gram fiber to about 10 ppm ammonia / gram fiber 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 Vitamin fiber has a brightness of between about 85 to about 92 and can reduce odor. For example, the modified cellulose may have a brightness of between about 85 to about 92 and absorb from about 5 ppm ammonia / gram fiber to about 10 ppm ammonia / gram fiber.

In some embodiments, the modified cellulose fiber is less than 2 on 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 oxidized cellulose, specifically cellulose including aldehyde and / or carboxylic acid groups, exhibits antiviral and / or antimicrobial activity. For example, see Song et al., Novel anliviral activity of dialdehyde starch, Electronic J. Biotech., Vol. 12, No. 2, 2009; US Patent No. 7,019,191 issued 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 commonly used in wound care applications, this part The ground system has bactericidal and hemostatic properties. Therefore, in some embodiments, the cellulose fibers of the present disclosure may exhibit antiviral and / or antimicrobial activity. In at least one embodiment, the modified cellulose fiber exhibits antibacterial activity. In some embodiments, the modified cellulose 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). The stable DP can be measured by methods known in the industry, 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, method from March to mid-April 1955.

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

In some embodiments, the modified kraft fiber is kraft fiber bleached in a multi-stage process, wherein at least one bleaching step is performed after the oxidation step. In these embodiments, the modified fiber after at least one bleaching step has a "k value" between about 0.2 and about 1.2, as measured according to TAPPI UM 251. For example, the k value may be between about 0.4 to about 1.2 or about 0.6 to about 1.2 or about 0.8 to about 1.2 or about 1.0 to about 1.2.

In some embodiments, the modified cellulose fiber has 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 may be greater than about 3. In some embodiments, the copper value is between about 2.5 to about 5.5, such as about 3 to about 5.5, such as about 3 to about 5.2.

In at least one embodiment, the modified kraft fiber has substantially the same hemicellulose content as standard unbleached kraft fiber. For example, the hemicellulose content of softwood kraft fiber can be between about 16% to about 18%. For example, the hemicellulose content of hardwood kraft fiber can be between about 18% and about 25%.

III. Further processing-acid / alkali hydrolysis

In some embodiments, the modified kraft fiber of the present disclosure is suitable for producing cellulose derivatives, for example, suitable for producing lower viscosity cellulose ethers, cellulose esters, and microcrystalline cellulose. In some embodiments, the modified kraft fiber of the present disclosure is a hydrolyzed modified kraft fiber. As used herein, "hydrolyzed modified kraft fiber", "hydrolyzed kraft fiber" and the like should be understood to mean fibers that are hydrolyzed using any known acid or alkali treatment to depolymerize cellulose chains. 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 acid or alkali.

In some embodiments, the present disclosure provides a method of treating kraft fiber, which includes bleaching the kraft fiber of the present disclosure, and then hydrolyzing the bleached kraft fiber. The hydrolysis can be carried out by any method known to those skilled in the art. In some embodiments, at least one acid-hydrolyzed bleached kraft fiber is used. In some embodiments, an acid selected from sulfuric acid, mineral acid, and hydrochloric acid is used to hydrolyze the bleached kraft fiber.

This disclosure also provides methods for producing cellulose ethers. In some embodiments, the method of producing cellulose ethers includes bleaching the kraft fiber of the present disclosure, treating the bleached kraft fiber with at least one alkaline agent, such as sodium hydroxide, and reacting the fiber with at least one etherifying agent.

The disclosure also provides methods for producing cellulose esters. In some embodiments, the method of producing cellulose esters includes bleaching the kraft fiber of the present disclosure, treating the bleached kraft fiber with a catalyst (eg, sulfuric acid), and then treating the fiber with at least one acetic anhydride or acetic acid. In an alternative embodiment, the method of producing cellulose acetate includes 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 disclosure also provides methods for producing microcrystalline cellulose. In some embodiments, the method of producing microcrystalline cellulose includes providing the bleached kraft fiber of the present disclosure, using at least one acid to hydrolyze the bleached kraft fiber until the desired DP is reached or under conditions to achieve a stable DP. In another embodiment, the hydrolyzed bleached kraft fiber is processed mechanically (eg, by milling, grinding, or shearing). Those skilled in the art know methods for mechanically treating hydrolyzed kraft fiber in the production of microcrystalline cellulose, and can provide the desired particle size. Other parameters and conditions for producing microcrystalline cellulose are known, and are described in, for example, US 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 agent or a caustic agent to reduce its viscosity and / or degree of polymerization. Alkaline treatment (pH above about 9) causes the dialdehyde to react and β-hydroxyl elimination. This further modified fiber treated with alkaline reagents 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 to replace some or all of the strength modifiers used to produce paper towels and towel products.

As mentioned above, there are three types of fiber products that can be made by the process described herein. The first category is fibers treated by catalytic oxidation. The fibers are almost indistinguishable from their conventional counterparts (at least with regard to physical and papermaking properties), but they have functionalities associated with them to impart one or more of the following properties For: Odor control properties, compressibility, low and ultra-low DP and / or "in situ" conversion to low DP under alkaline or acid hydrolysis conditions (e.g. cellulose derivative production (e.g. ether or acetate) production conditions) The ability of low viscosity fiber. The physical properties and papermaking properties of such fibers make them suitable for typical papermaking and absorbent product applications. On the other hand, the increased functionality (such as aldehydes and carboxylic acids) and properties related to the functionality make this fiber more desirable and more versatile than standard kraft fiber.

The second type of fibers are fibers that are subjected to catalytic oxidation and then treated with alkaline or caustic reagents. The alkaline reagent causes the fiber to decompose at the site of the carbonyl functionality increased through the oxidation process. This fiber has physical and papermaking properties that are different from fibers that are only subjected to oxidation, but can exhibit the same or similar DP values because the test used to measure viscosity and thus DP subjects the fiber to caustic reagents. Those skilled in the art will understand that different alkaline reagents and contents can provide different DP values.

The third type of fiber is a fiber that is subjected to catalytic oxidation and then treated in an acid hydrolysis step. Acid hydrolysis makes it possible for the fiber to decompose to the extent consistent with its stable DP.

In some embodiments, the fibers produced as described can be treated with surfactants. The surfactant used in the present invention may be solid or liquid. The surfactant may be any surfactant, including but not limited to softeners, degumming agents, and surfactants that are insubstantial to the fiber (that is, do not interfere with its specific absorption rate). As used herein, surfactants that are "insubstantial" to the fibers exhibit a specific absorption increase of 30% or less, as measured using the pfi test as described herein. According to an embodiment, the specific absorption rate is increased by 25% or less, for example 20% or less, for example 15% or less, for example 10% or less. Undesirable Theoretically, the addition of surfactant causes competition with the test fluid for the same site on cellulose. Therefore, when the surfactant has too large a substance, it reacts at too many sites, thereby reducing the absorption capacity of the fiber.

As used in this article, PFI is measured according to the SCAN-C-33: 80 test standard, Scandinavian Pulp, Paper and Board Testing Committee. The method is usually as follows. First, a PFI pad making machine was used to prepare samples. The vacuum was turned on and approximately 3.01 g of fluff pulp was fed into the inlet of the pad machine. Turn off the vacuum, remove the test part and place it on the balance to check the quality of the pad. The fluff quality was adjusted to 3.00 + 0.01g and recorded as dry mass. Place the fluff in the test cylinder. Place the cylinder containing fluff in the shallow porous disk of the absorption tester and open the water valve. Lightly apply a 500g load to the fluff pad while lifting the test part cylinder and quickly pressing the start button. The tester will run for 30s before the display reads 00.00. When the display reading is 20 seconds, record to the nearest 0.5mm dry pad height (dry height). When the display reads 00.00 again, 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 automatically lowers and runs for another 30S. When the display reading is 20s, record to the nearest 0.5mm wet pad height (wet height). Remove the sample holder, transfer the wet pad to the balance for measuring the wet mass and close 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) is [19.64cm2 × wet height / 3] / 10. The dry volume is [19.64cm2 × dry height / 3] / 10. The reference standard used for comparison with surfactant-treated fibers is the same fiber with no surfactant added.

It is agreed that softeners and degummers are usually only purchased as complex mixtures rather than as single compounds. Although the following discussion focuses on the main substances, it should be understood that commercially available mixtures are usually used in practice. Those skilled in the art are easily aware of suitable softeners, degummers and surfactants and are widely reported in the literature.

Suitable surfactants include cationic surfactants, anionic surfactants, and nonionic surfactants that are not essential to the fiber. According to an embodiment, the surface activity The sex 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 vegetable-based fatty acids, such as vegetable-based fatty acid quaternary ammonium salts. 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 used. Representative biodegradable cationic softeners / gelling agents are disclosed in US Patent Nos. 5,312,522, 5,415,737, 5,262,007, 5,264,082, and 5,223,096, the entire contents of which are incorporated herein by reference. The compound is a biodegradable diester of a fourth-grade ammonia compound, a fourth-grade ammonium amine-ester, and a biodegradable vegetable oil-based biodegradable functional group having a fourth-grade ammonium chloride and a diester dicarbyldimethylammonium chloride Ester is a representative biodegradable softener.

The surfactant is added in an amount of up to 8 lbs / ton, for example 2 lbs / ton to 7 lbs / ton, for example 4 lbs / ton to 7 lbs / ton, for example 6 lbs / ton to 7 lbs / ton.

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

According to an embodiment, when used in a slime process, the fibers of the present invention have improved filtration rates compared to the same fibers without the addition of surfactants. For example, the filtration rate of the mucus solution including the fiber of the present invention is at least 10% lower than that of a mucus solution prepared in the same way using the same fiber without surfactant, such as at least 15% lower, such as at least 30% lower At least 40% lower. The filtration rate of the mucus solution was measured by the following method. Place the solution in a nitrogen-pressurized (27 psi) vessel with a 19 / 16-inch filter orifice at the bottom-the filter media from outside to inside of the vessel is as follows: porous metal disc, 20 mesh stainless steel screen, thin Gauze, Whatman 54 filter paper and double flannel with the fluff side up towards the contents of the vessel. Within 40 minutes, the solution was filtered through the medium, then at an additional 40 minutes of 40 minutes (Thus, at 40 minutes, t = 0), using the elapsed time as the X coordinate and the weight of the filtered mucus as the Y coordinate to measure (weight) the volume of the filtered solution-the slope of this graph is the filtered value. Record at 10 minute intervals. The reference standard used for comparison with surfactant-treated fibers is the same fiber with no surfactant added.

According to an embodiment of the present invention, the surfactant-treated fiber of the present invention exhibits a limited increase in specific absorption rate (eg, less than 30%), and at the same time, the filtration rate decreases (eg, at least 10%). According to an embodiment, the surfactant-treated fibers have an increased specific absorption rate 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 fibers have an increased specific absorption rate 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 fibers have an increased specific absorption rate of less than 20% and a reduced filtration rate of at least 10% (such as at least about 20%, such as at least 30%, such as at least 40%). According to another embodiment, the surfactant-treated fibers have an increased specific absorption rate of less than 15% and a reduced filtration rate of at least 10% (such as at least about 20%, such as at least 30%, such as at least 40%). According to another embodiment, the surfactant-treated fibers have an increased specific absorption rate 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

This disclosure provides products made from the modified kraft fiber described herein. In some embodiments, the products are those usually made from standard kraft fiber. In other embodiments, the products are those usually made from cotton linter or sulfite pulp. More specifically, the modified fiber of the present invention can be used to produce absorbent products without further modification and as a starting material for preparing chemical derivatives such as ethers and esters. So far, there is no fiber that can be used to replace high alpha content cellulose (such as cotton and sulfite pulp) and traditional kraft fiber.

Such as "can replace lint (or sulfite pulp) ..." and "can be used interchangeably with lint (or sulfite pulp) ..." and "can be used to replace lint ( Or sulfite pulp) ... "and the like only mean that the fiber has properties suitable for end-use applications usually made with cotton linter (or sulfite pulp). The phrase is not intended to mean that the fibers must have all the same characteristics as cotton wool (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, nursing pads, adult incontinence products, feminine hygiene products (eg, including sanitary napkins and cotton balls), Airflow nonwoven products, airflow composites, "tabletop" handkerchiefs, napkins, paper towels, towels and the like. The absorbent product of this disclosure may be disposable. In their embodiments, the modified fibers of the present invention can completely or partially replace bleached hardwood or softwood fibers that are commonly used to produce such products.

In some embodiments, the modified cellulose fiber is in the form of fluff pulp and has one or more properties that make the modified cellulose fiber more effective in absorbent products than conventional fluff pulp. More specifically, the modified fiber of the present invention may have improved compressibility and improved odor control, all of which allow it to desirably replace currently available fluff pulp fibers. Because the fibers of the present disclosure have improved compressibility, they can be used in embodiments that seek to produce thinner, more compact absorbent structures. After understanding the compression properties of the fiber of the present disclosure, those skilled in the art can easily design absorbent products that can use the fiber. For example, in some embodiments, the present disclosure provides ultra-thin sanitary products that include the modified kraft fiber of the present disclosure. Ultra-thin fluff cores are commonly used in, for example, feminine hygiene products or baby diapers. Other products that can be produced using the fibers of the present disclosure can be anyone who needs an absorbent core or compressed absorbent layer. Upon compression, the fibers of the present invention do not exhibit absorption losses or no substantial absorption losses, but exhibit improved flexibility.

According to an embodiment, the absorbent product may be a product that absorbs and retains urine, such as diapers or incontinence devices. Such devices usually contain absorbent fluff cores. The fibers of the present disclosure can be used to create absorbent devices that can improve wicking and retention, thereby gaining more Comfortable clothing or equipment.

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

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

Compared to products made from fibers that have not been subjected to an oxidation step, the products described can exhibit improved flexibility (especially when used on the curved side of multilayer cores), improved dimensional stability (after stimulation), and improvements The 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 may include one or more fiber layers, which are treated in different ways to improve the overall uptake and retention of the device. As used herein, treatment refers to any chemical or physical process that changes the absorbency, wicking, or retention of fibers. A common treatment is the addition of surfactants. According to an embodiment, the core may have multiple layers, such as 2, 3, 4, or 5. According to an embodiment, the fibers of the invention can be used in any layer of a 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 core that is first stimulated by urine and closest to the skin. Similarly, "bottom" refers to the layer farthest from the user. The other layers may be called "intermediate layers". The fibers of the present disclosure can be used in an "untreated" state, which means that the fibers are not post-treated (for example) with a surfactant. Fibers can also be used in a "treated" state, which means fibers are modified by including surfactants. The treated or untreated fibers can be used in any layer and 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 yet another embodiment, the fibers of the present invention are used in the middle layer of the 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 in the top and bottom layers of the absorbent core. In addition, the fibers of the present disclosure can be used in the top layer, bottom layer, and middle layer of the absorbent 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 yet another embodiment, the fibers in the middle layer are treated fibers.

The treated fibers and untreated fibers of the present disclosure can be combined in a single layer or can be used in separate layers of the absorbent core. According to an embodiment, the top layer of the absorbent core includes the untreated fibers of the present disclosure and the bottom layer of the absorbent core includes the treated fibers of the present disclosure. According to another embodiment, the treated fiber of the present disclosure is used to manufacture an absorbent core The top layer of the heart uses the untreated fibers of the present disclosure to make one or more middle layers and the treated fibers of the present disclosure to make the bottom layer.

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

Without further modification, the modified fibers of the present invention can also be used to produce absorbent products, including but not limited to paper towels, towels, napkins, and other paper products formed on traditional papermaking machines. The traditional papermaking process involves preparing an aqueous fiber slurry that is usually deposited on a forming line where water is subsequently removed. The increased functionality of the modified cellulose fibers of the present disclosure can provide improved product characteristics to products containing such modified fibers. For the reasons mentioned above, the modified fiber of the present invention may allow products made using it to exhibit improved strength, which may be related to the increased functionality of the fiber. The modified fiber of the present invention can also obtain products with improved flexibility.

In some embodiments, without further modification, the modified fibers of the present disclosure can be used to make cellulose ethers (eg, carboxymethyl cellulose) and esters instead of having a very high DP of about 2950 to about 3980 (also That is, fibers with viscosities between about 30 mPa‧s to about 60 mPa‧s, as measured by 0.5% capillary CED) and very high cellulose percentages (eg 95% or greater, eg they are derived from cotton wool And bleached softwood fibers produced by the acid sulfite pulping process). The modified fiber of the present invention that has not been subjected to acid hydrolysis is usually subjected to this acid hydrolysis treatment in the production process for producing cellulose ethers or esters.

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

V. Acid / alkali hydrolysis products

In some embodiments, the present disclosure provides a substitute for cotton wool or sulfite Modified kraft fiber of pulp. In some embodiments, the present disclosure provides modified kraft fiber that can be used, for example, to produce cellulose ether, cellulose acetate, and microcrystalline cellulose instead of cotton wool or sulfite pulp.

Without being bound by theory, it is believed that increasing the aldehyde content relative to conventional kraft pulp will provide additional activity for etherification to the final product (eg, carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, and the like) Sites, thereby enabling the production of fibers that can be used in papermaking and cellulose derivatives.

In some embodiments, the modified kraft fiber has chemical properties that make it suitable for making cellulose ethers. Therefore, the present disclosure provides cellulose ethers derived from the modified kraft fiber. In some embodiments, the cellulose ether is selected from ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl methyl cellulose. It is believed that the cellulose ether of the present disclosure can be used in any application where cellulose ether is generally used. By way of example, and not limitation, the cellulose ethers of the present disclosure can be used in coatings, inks, adhesives, controlled-release drug tablets, 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 derived from the modified kraft fiber of the present disclosure, such as cellulose acetate. In some embodiments, the present disclosure provides products that include cellulose acetate derived from the modified kraft fiber of the present disclosure. By way of example and not limitation, the cellulose esters of the present disclosure can be used in household furniture, cigarettes, inks, absorbent products, medical devices, and plastics (including, for example, 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 highly purified starting cellulose materials that require relatively clean. Therefore, traditionally, expensive sulfite pulp is mainly used for its production. This disclosure provides microcrystalline cellulose derived from the modified kraft fiber of this disclosure. Therefore, this disclosure provides cost-effective cellulose for the production of microcrystalline cellulose to source. In some embodiments, the microcrystalline cellulose is derived from modified kraft fiber with a DP of less than about 100 (eg, less than about 75 or less than about 50). In some embodiments, the microcrystalline cellulose system is derived from an R10 value between about 65% and about 85% (e.g., about 70% to about 85% or about 75% to about 85%) and an R18 value between about Between 75% and about 90% (eg, about 80% to about 90%, such as about 80% to about 87%) of the modified kraft fiber.

The modified cellulose of the present disclosure can be used in any application where microcrystalline cellulose is commonly used. By way of example and not limitation, the modified cellulose of the present disclosure can be used in medical or nutritional applications, food applications, cosmetic applications, paper applications, or as structural composites. For example, the modified cellulose of the present disclosure can be binders, diluents, disintegrants, lubricants, tableting aids, stabilizers, conditioners, fat substitutes, build-up agents, anti-caking agents , Foaming agents, emulsifiers, thickeners, separating agents, gelling agents, carrier materials, opacifiers or viscosity modifiers. In some embodiments, the microcrystalline cellulose is colloidal.

VI. Products including acid hydrolysis products

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

In some embodiments, the present disclosure provides food products that include bleached kraft fiber of the present disclosure that has been hydrolyzed. In some embodiments, the present disclosure provides food products that include at least one product derived from the cattle bleached leather fiber of the present disclosure. In other embodiments, the present disclosure provides food products that include microcrystalline cellulose derived from kraft fiber of the present disclosure. In some embodiments, the food product includes colloidal microcrystalline cellulose derived from kraft fiber of the present disclosure. Food products can Any food product that normally uses microcrystalline cellulose. Those skilled in the art are familiar with exemplary food types that can use microcrystalline cellulose and can refer to, for example, Codex Alimentarius (eg, Table 3). For example, the microcrystalline cellulose derived from the chemically modified kraft fiber of the present disclosure may be an anti-caking agent, accumulating agent, emulsifier, foaming agent, stabilizer, thickener, gelling agent and / or Or suspending agent

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

As used in this article, "about" is intended to explain changes caused by experimental errors. Unless specifically stated otherwise, all measured values should be understood as modified by the word "about", whether or not explicitly stated as "about". Thus, for example, the statement "fiber with a length of 2 mm" should be understood to mean "fiber with 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. After considering the present disclosure, those skilled in the art should understand other embodiments of the present invention.

Examples A. Test plan

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

2. Measure the carboxyl content according to TAPPI T237-cm98.

3. Measure the aldehyde content according to the special program ESM 055B of Econotech Services Co., 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 viscosity of 0.5% capillary CED according to TAPPI T230-om99.

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

8. Calculate the viscosity from 0.5% capillary CED according to the formula: DPw = -449.6 + 598.4ln (0.5% capillary CED) + 118.02ln ² (0.5% capillary CED), calculate the DP, 1994 Cellucon Conference, published in The Chemistry and Processing Of Wood And Plant Fibrous Materials , page 155, Woodhead Publishing Co., Abington Hall, Abington, Cambridge CBI 6AH, England, JF Kennedy and others.

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

10. From the carbohydrate composition, the cellulose content is calculated according to the formula: cellulose = dextran- (mannan / 3), TAPPI Journal 65 (12): 78-80 1982.

11. Calculate the hemicellulose content by subtracting the cellulose content from the total sugar content.

12. Measure cellulose length and roughness on Fiber Quality Analyzer ^TM from OPTEST, Hawkesbury, Ontario according to manufacturer's standard procedures.

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

14. Measure the degrees of freedom according to TAPPI T227-om99.

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

16. Determine the DCM (dichloromethane) extract according to TAPPI T204-cm97.

17. Determine the 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 the brightness according to TAPPI T525-om02.

21. Measure the porosity according to TAPPI 460-om02.

22. Determine the burst factor according to TAPPI T403-om02.

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

24. According to TAPPI T494-om01 to determine the length of rupture and elongation.

25. Determine opacity according to TAPPI T425-om01.

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

27. Determine the fiber length and form factor on the L & W fiber tester from Lorentzen & Wettre, Kista, Sweden according to the manufacturer's standard procedures.

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

B. Exemplary method of manufacturing modified cellulose fibers

Semi-bleached or substantially bleached kraft pulp can be treated with acid, iron and hydrogen peroxide to reduce fiber viscosity or DP. Sulfuric acid, hydrochloric acid, acetic acid, or filtrate from the scrubber of the acid bleaching stage (eg, chlorine dioxide stage) can be used to adjust the fiber to a pH of about 2 to about 5 (if not already in this range). 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). The ferrous sulfate can be dissolved in water at a concentration between about 0.1 g / L and about 48.5 g / L. The ferrous sulfate solution can be added at an application rate (in the form of Fe ⁺² based on the dry weight of the pulp) of between about 25 ppm to about 200 ppm. The ferrous sulfate solution can then be thoroughly mixed with the pH-adjusted pulp (thickness of about 1% to about 15%, measured as the dry pulp content of the total wet pulp mass). An aqueous solution of hydrogen peroxide (H ₂ O ₂ ) can then be added at a concentration of about 1% to about 50% by weight H ₂ O ₂ and in an amount of about 0.1% to about 3% (based on the dry weight of the pulp). The pulp mixed with ferrous sulfate and peroxide (pH of about 2 to about 5) can be reacted at a temperature of about 60 ° C to about 80 ° C for a time between about 40 minutes to 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 applied peroxide and iron, residence time and temperature.

Treatment can be achieved using standard sequences 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 preferably be used for processing. The fibers on the D1 stage scrubber can be adjusted to a pH of about 2 to about 5 by adding acid or filtrate from the D2 stage as needed. The ferrous sulfate solution can be added to the pulp by: (1) spraying it on the D1 stage scrubber felt through an existing shower head or new head, (2) adding it through the spray mechanism at the pulper, Or (3) Add via the point of addition 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 before the fourth stage column. Optionally, steam can be added before the tower in the steam mixer. The pulp can then react in the tower for an appropriate residence time. The chemically modified pulp can then be washed on the stage 4 scrubber in the normal way. Depending on the situation, additional bleaching can be achieved by the fifth or D2 stage operating in the normal way after treatment.

Example 1 Method for preparing fibers of this disclosure A. Grinding method A

The southern pine wood cellulose is digested and oxygen delignification is performed in a conventional two-stage oxygen delignification step until the Kappa value is about 9 to about 10. The delignified pulp is bleached in a 5-stage bleaching plant using the sequence D ₀ (EO) D1E2D2. Prior to stage 4 or E2, the filtrate from stage D of the sequence is used to adjust the pH of the pulp to a range of about 2 to about 5. After adjusting the pH, adding to the E2 phase column kraft fiber 0.2% hydrogen peroxide (based on pulp dry weight) and 25ppm Fe ⁺² (as a form of FeSO ₄ .7H ₂ O, based on the dry weight of the pulp) and about 78 The reaction is carried out at a temperature of from ℃ to about 82 ℃ for about 90 minutes. The reacted fibers are then washed on the stage 4 scrubber, and then bleached in stage 5 (D2) 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 .

Exemplary fiber properties

After the above five-stage bleaching sequence, the fiber samples prepared according to grinding methods A (Sample 2), B (Sample 3), and C (Sample 4) were collected. Measure some of these samples as well as standard fluff grade fibers (GP Leaf River Cellulose, New Augusta, MS; sample 1) and commercially available samples (PEACH ^™ , sold by Weyerhaeuser; sample 5) according to the above scheme 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 processed under the same conditions as those reported for Sample 1 was obtained. The iron content of their 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 some differences in the total carbonyl content, carboxyl content and aldehyde content different. Due to the difference between the total carbonyl group and the aldehyde group, the additional carbonyl functional group can be in the form of other ketones. The data shows that a relatively high aldehyde content can be achieved while retaining carboxylic acid groups while maintaining the 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 also relatively strong and absorbent.

As can be seen in Table 1, the standard down grade fiber (Sample 1) has a carboxyl content of 3.13 meq / 100g and an aldehyde content of 0.97 meq / 100g. Low-dose treatment with 0.2% H ₂ O ₂ and 25 ppm Fe ⁺² (sample 2) or higher-dose treatment with 0.6% H ₂ O ₂ and 75 ppm Fe ⁺² (sample 3) or 1.4% H ₂ O ₂ and 100 ppm Fe ⁺² were treated at a higher dose (Sample 4), the fiber length and the calculated cellulose content were relatively unchanged, and the fiber strength (as measured by the wet zero distance method) was slightly reduced , But the content of carboxyl, carbonyl and aldehydes have increased, indicating that cellulose has undergone extensive oxidation.

In contrast, commercially available samples of oxidized kraft cork southern pine fiber prepared by the alternative method (sample 5) showed significantly shorter fiber lengths and fibers compared to the down grade fibers as reported in sample 1 The strength (as measured by the wet zero-distance method) is lost by about 70%. The aldehyde content of sample 5 is practically unchanged compared to standard fluff-grade fibers, and the inventive fiber (sample 2-4) prepared by the grinding method AC has a highly increased aldehyde content, such as about 70% to Approximately 100% of the total calculated carbonyl content of cellulose is represented. In contrast, PEACH® aldehyde content is less than 30% of the total calculated carbonyl content of cellulose. The ratio of total carbonyl to aldehyde appears to be a good indicator of fibers with broad applicability of modified fibers within the scope of this disclosure, especially when the ratio is in the range of about 1 to about 2, as in samples 2-4. Low viscosity fibers with a carbonyl / aldehyde ratio of about 1.5 to less than 2.0 (e.g., samples 3 and 4) will maintain the fiber length, as opposed to the other samples of comparative sample 5.

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 cellulose 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

Use hydrogen peroxide (apply 0.25% to 1.5%) and 50 or 100 ppm Fe ⁺² (added in the form of FeSO ₄ ‧7H ₂ O) at about 10% consistency to treat bleaching equipment from OD (EOP) D (EP) D D1 stage 0.5% capillary CED viscosity is about 14.6mPa‧s samples of southern pine pulp. Add Fe ⁺² aqueous solution and mix well with the pulp. Then a 3% aqueous solution of hydrogen peroxide was mixed with the pulp. The mixed pulp was kept in a water bath at 78 ° C for 1 hour. After the reaction time, filter the pulp and measure the pH and residual peroxide of the filtrate. Wash the pulp and determine the 0.5% capillary CED viscosity according to TAPPI T230. The results are shown in Table 3.

Example 3

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

Example 4

In the same manner as described in Example 2, 0.75% hydrogen peroxide and 150 ppm Fe ^{+2 were used to} treat 0.5% capillary CED with a viscosity of 14.8 mPa‧s (DPw 2020) from the bleaching equipment described in Example 2. For the sample, the processing time is only 80 minutes. The results are shown in Table 5.

Example 5

At 10% consistency using hydrogen peroxide (0.25 wt% is applied or 0.5 wt%, based on pulp) and 25ppm, 50ppm or 100ppm Fe ⁺² (added in the form of FeSO ₄ .7H ₂ O) from the processing OD ₀ (EO) D1 (EP) Southern Pine wood pulp with 0.5% capillary CED viscosity of 15.6mPa‧s (DPw 2085) in D1 stage of D2 sequence. Add Fe ⁺² aqueous solution and mix well with the pulp. Then a 3% aqueous solution of hydrogen peroxide was mixed with the pulp, and the mixed pulp was kept in a water bath at 78 ° C for 1 hour. After the reaction time, filter the pulp and measure the pH and residual peroxide of the filtrate. Wash the pulp and determine the 0.5% capillary CED viscosity 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 25ppm, 50ppm or 75ppm Fe ⁺² was 15.2mPa Another sample. The results are shown in Table 7.

Example 7

After increasing the degree of delignification in the kraft paper and oxygen stages to produce pulp with a lower DPw or 0.5% capillary CED viscosity, southern pine pulp was collected from the D1 stage of the OD (EO) D (EP) D bleaching sequence. The initial 0.5% capillary CED viscosity was 12.7mPa‧s (DPw 1834). Add 0.50% or 1.0% hydrogen peroxide and 100ppm Fe ⁺² . Other treatment conditions are 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, 0.5% capillary CED viscosity of D1 pulp from D1 stage of OD (EO) D (EP) D sequence was treated with 0.75% or 1.0% hydrogen peroxide and 75ppm or 150ppm Fe ⁺² with a viscosity of 11.5 The low viscosity sample of mPa‧s (DPw 1716) only has a processing time of 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 11.6mPa‧s (DPw 1726). Add 1.0%, 1.5% or 2% hydrogen peroxide and 75ppm, 150ppm or 200ppm Fe ⁺² . Other treatment conditions are 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‧s (DPw 1986). Add 1.0%, 1.5% or 2% hydrogen peroxide and 75ppm, 150ppm or 200ppm Fe ⁺² . Other treatment conditions are 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 15.3mPa‧s (DPw 2061). Add 3% (based on pulp) hydrogen peroxide and 200 ppm Fe ⁺² . Other treatment conditions are 10% consistency, 80 ° C and 1.5 hour reaction time. The results are shown in Table 12.

Examples 2-11 above show that using the acidic, catalytic, peroxide treatment of the present disclosure can achieve a significant reduction of 0.5% capillary CED viscosity and / or degree of polymerization. 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 pulp from two different factories ("Brunswick" and Leaf River ("LR")) Percent change in consumed peroxide. The peroxide consumed varies with the amount and concentration of applied peroxide and iron, reaction time and 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 is 14.8mPa‧s (DPw 2020). 1% (based on pulp) hydrogen peroxide was added and 100pm, 150pm or 200pm Cu ⁺² (in the form of CuSO ₄ .5H ₂ O). Other treatment conditions are 10% consistency, 80 ° C and 3.5 hours reaction time. The results are shown in Table 13.

Compared with untreated control pulp, the use of copper instead of iron will slow down the reaction and reduce the lower viscosity reduction, but still significantly change the viscosity, carboxyl content and aldehyde content.

Example 13

Changing the E2 (EP) stage of the OD (EOP) D (EP) D sequence to produce ultra-low polymerization pulp. At the scrubber pulper in stage D1, FeSO _{4 was} applied in the form of Fe ⁺² at an application rate of 150 ppm. The 7H ₂ O solution was sprayed on the pulp. No caustic (NaOH) was added to the E2 stage and the peroxide application was increased to 0.75%. The residence time is about 1 hour and the temperature is 79 ° C. The pH is 2.9. The treated pulp was washed on a vacuum drum washer and then treated with 0.7% ClO ₂ at 91 ° C. for approximately 2 hours in the final D2 stage. The final 0.5% capillary CED viscosity of the bleached pulp is 6.5mPa. 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 with a standard dryer. Samples of control pulp and pulp of the present invention (ULDP) were collected and analyzed for chemical composition and fiber properties. The results are shown in Table 14.

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

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 ultra-low polymerization pulp. In this example, add 75ppm FeSO ₄ . 7H ₂ O (in the form of Fe ⁺² ) and the hydrogen peroxide applied in the E2 stage is 0.6%. The pH of the treatment stage was 3.0, the temperature was 82 ° C, and the residence time was approximately 80 minutes. The pulp was washed and then treated with 0.2% ClO ₂ at 92 ° C for approximately 150 minutes in the D2 stage. The fully bleached pulp has a 0.5% capillary CED viscosity of 5.5 mPa‧s (DPw 914) and an ISO brightness of 88.2.

Example 16

The pulp produced in Example 15 was made into a pulp board on a Fourdrinier type pulp dryer with an air cushion Flakt ^™ dryer section. Samples of standard pulp and pulp of the present invention (ULDP) were collected and analyzed for chemical composition and fiber properties. The results are shown in Table 15.

Treated pulp (ULDP) has higher 10% and 18% NaOH basic solubility and 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-pitch break length. The brightness is still an acceptable value of 88.2. The treatment maintains the fiber length and freeness and there are no operational issues regarding the formation and drying of the board.

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 low degree of polymerization pulp. In this case, add 25ppm FeSO ₄ . 7H ₂ O (in the form of Fe ⁺² ) and the hydrogen peroxide applied in the E2 stage is 0.2%. The pH of the treatment stage was 3.0, the temperature was 82 ° C, and the residence time was approximately 80 minutes. The pulp was washed and then treated with 0.2% ClO ₂ at 92 ° C for approximately 150 minutes in the D2 stage. The fully bleached pulp has a 0.5% capillary CED viscosity of 8.9 mPa‧s (DPw 1423) and an ISO brightness of 89.

Example 18

The pulp produced in Example 15 was made into a pulp board on a Fourdrinier type pulp dryer with an air cushion Flakt ^™ dryer section. Samples of standard pulp and low-polymerization pulp (LDP) of the present invention were collected and analyzed for chemical composition and fiber properties. The results are shown in Table 16.

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

Example 19

The pulp board described in Example 14 was subjected to fiberization and air-formed into a 4 "× 7" pad using a Kamas laboratory hammer mill (Kamas Industries, Sweden). Then use a laboratory press to compress the air forming pads under various gauge pressures. After pressing, the thickness of the pad was measured using a 200-A Emveco precision ultrasonic thickness gauge caliper with a plantar pressure of 0.089 psi. The pad density is calculated from the pad weight and thickness. The results are shown in Table 17.

The data in Table 17 shows that the resulting modified fibers within the scope of this 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 cellulose oxidation destroys the crystalline structure of the polymer, making it less rigid and more compliant. Fiber composed of modified cellulose structure It then becomes more compressible, resulting in a higher density absorbent 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 14.9mPa‧s (DPw 2028). Add 1.0% or 2% hydrogen peroxide and 100ppm or 200ppm Fe ^{+2, respectively} . Other treatment conditions are 10% consistency, 80 ° C and 1 hour residence time. The fluff pulp was then slurried with deionized water, wet cloth layered on a screen to form a fiber mat, dewatered via a roller press, and dried at 250 ° F. The dried sheet was defibrillated and air-formed using a Kamas laboratory hammer mill (Kamas Industries, Sweden) into a 4 "x 7" air cloth mat (air-dried) weighing 8.5 grams. A single complete cover sheet of nonwoven fabric was applied to one side of each pad and the sample was densified using a Carver hydraulic flat press with a load of 145 psig.

Place these pads in individual 1.6L airtight plastic containers with removable covers fitted with inspection valves and sampling ports with ¼ "ID Tygon® tubing. Before securing the container cover, at room temperature Next, pour 60 grams of deionized water and 0.12 grams of 50% NH ₄ OH irritant into the center 1 ”ID vertical tube on the delivery device, which can apply a 0.1 psi load to the entire sample. After the stimulus is completely absorbed, the delivery device is removed from the sample, a lid with a sealed sampling port is fitted to the container, and the countdown timer is turned on. At the end of 45 minutes, headspace samples were obtained from the sampling port of the ammonia-selective short-term gas detection tube and ACCURO® bellows pump (both available from Draeger Safety, Pittsburgh, PA). The data in Table 18 shows that the modified fibers produced within the scope of this disclosure can reduce the amount of ammonia in the headspace, resulting in compounds that suppress volatile odors (usually cited as unpleasant in wetting incontinence products) Material) structure.

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 changed 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.

The resulting modified chemical cellulose was made into a pulp board on a Fourdrinier type pulp dryer with an air cushion Flakt ^™ dryer section. A Kamas laboratory hammer mill was used to defibrillate this product and the control kraft pulp board samples. The fiber properties of the samples before and after Kamas grinding were optically analyzed by the HiRes fiber quality analyzer available from Optest Equipment Company, Hawkesbury, ON, Canada according to the manufacturer's protocol. The results are shown in the table below.

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

The defibrillated fibers were air-formed into 4 "x 7" mats (air-dried) weighing 4.25 grams. Sodium polyacrylate superabsorbent (SAP) particles derived from BASF were evenly applied between two 4.25 g pads. Fully covered nonwoven fabric was applied to the top surface of the fiber / SAP substrate and the pad was densified by a 145 psig load applied via a Carver flat press.

Synthetic urine is prepared by: dissolving 2% urea, 0.9% sodium chloride, and 0.24% nutrient broth (Criterion ^TM brand, available through Hardy Diagnostics, Santa Maria, CA) in deionized water, and adding ordinary An aliquot of Proteus Vulgaris was used to obtain a starting bacterial concentration of 1.4 × 10 ⁷ CFU / ml. The pad was then placed in the headspace chamber as explained in Example 20 and stimulated with 80 ml of synthetic urine solution. Immediately after stimulation, the chamber was sealed and placed in an environment with a temperature of 30 ° C. Dräger sampling was continuously performed at intervals of 4 hours and 7 hours. The experiment was repeated three times, and the average results are reported in Table 21.

As can be seen from the data, the atmospheric ammonia derived from the hydrolysis of urea bacteria in the composite structure of modified cellulose fibers produced within the scope of this disclosure (which has a structure similar to retail urinary incontinence products) is lower than using standard kraft paper southern A composite structure produced by pine fibers. Therefore, the odor control properties of the structure of the modified cellulose fiber including the present disclosure is superior to the standard kraft southern pine fiber.

Example 22-Comparison between 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 weight of pulp) and 150 ppm Fe ^{+2 were added} . As used herein, "P *" is used to indicate the iron and hydrogen peroxide treatment stage. In the fourth stage of the sequence, the treatment was carried out at a consistency of 10% and a temperature of 78 ° C for 1 hour. This treated pulp was then washed and bleached with 0.25% ClO ₂ at 78 ° C for 2 hours in 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. The brightness and L * (whiteness), a * (red to green), and b * (blue to yellow) values were measured by Hunterlab MiniScan before and after the color reversion process according to the manufacturer's protocol. The results are shown in Table 23 below. A positive b value indicates more yellow. Therefore, higher b values are undesirable in most paper and pulp applications. The fade values reported below represent the difference between the ratio k / s before and after aging, where k = absorption coefficient and s = scattering coefficient, that is, fade value = 100 {(k / s) _after aging- ( k / s) _{before aging} }. See for example HWGiertz, Svensk Papperstid, 48 (13), 317 (1945).

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

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

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

As can be seen from the above data, the acid-catalyzed peroxide treatment in the fourth stage of the 5-stage bleaching plant gives beneficial brightness properties compared to the treatment after the final stage of the 5-stage bleaching plant. In the fourth stage of processing, any brightness loss from this processing stage can be Compensated by the final D2 bleaching stage, thereby still obtaining high brightness pulp. In the case of post-bleaching treatment, the brightness is significantly lost by 3.4 points and cannot be compensated. After the accelerated color reversion process, the latter case still has significantly lower brightness.

Example 23 Intensity data

Compare the strength of the fluff pulp produced from the modified cellulose with a viscosity of 5.1 mPa‧s from this disclosure with the conventional fluff pulp with a viscosity of 15.4 mPa‧s. The results are shown in Table 26 below.

Example 24 Derivation of modified cellulose

The ULDP sample from Example 21 was acid hydrolyzed using 0.05M 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 were tested by the following method.

Three pulp samples were milled to pass a 20 mesh screen. The cellulose sample (15 mg) was placed in a separate test tube of a micro stir bar and dried under vacuum at 40 ° C overnight. Then use a rubber septum to cap the test tube. Anhydrous pyridine (4.00 mL) and phenyl isocyanate (0.50 mL) were added sequentially via syringe. Place the test tube in a 70 ° C oil bath and stir for 48h. 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 derived cellulose. The solid was collected by filtration and then washed with methanol / water (1 × 50 mL), followed by water (2 × 50 mL). The derived cellulose was then dried under vacuum at 40 ° C overnight. Prior to GPC analysis, the derived cellulose was dissolved in THF (1 mg / mL), filtered through a 0.45 μm filter, and placed in a 2 mL autosampler vial. The resulting DPw and DPn (number-average degree of polymerization) are reported in Table 27 below.

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

Example 25

Leaf River ULDP fibers and standard cork fibers are made into handsheets by making the fibers a slurry, adjusting the pH to about 5.5, and then adding glyoxylated polypropylene amide from Kemira Chemicals as a temporary wet strength agent . The fibers are then formed, pressed into sheets and dried. The sheet properties are measured by known methods. The results are reported on 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, handsheets formed from ULDP have a wet / dry ratio that is higher than that of the control sheet obtained only from standard southern cork.

Example 26 Wicking, rewetting and strength data

Various densities (0.15g / cm ³ , 0.25g / cm ³ and 0.35g / cm ³ ) and basis weight (60gsm, etc.) prepared from pulp produced from modified cellulose and 10% bicomponent fibers using this disclosure The synthetic urine wicking capacity of 150gsm, 300gsm) sheets was compared with sheets made from self-study kraft pulp. With Materials Testing Service of Kalamazoo, Ml uses its own testing equipment and procedures to carry out the tests. Use 6.0cm × 16.0cm sample and 600 seconds lead reading time to test the synthetic urine wicking ability of the product. The results are shown in Table 29 below.

The retention, thickness change and wicking height are also measured. The results are shown in Table 30 below:

A rewetting test was also performed on the same sheet. Use 9.0cm × 20.3cm to cut the sample Use a drop tube method and a 10ml 0.9% saline solution to test the rewetting of the product. 120 seconds after application, the application tube was removed and the recorded pre-weighed 6 "x 6" sheet of Verigood blotting paper was placed on top and a 3 kpa load was applied for 60 seconds. The results are shown in Table 31 below.

The same sheets were also tested for dry and wet tensile strength and percent elongation. The tensile strength and percent elongation of each product were measured in the machine direction using a 5.00 cm gauge length, 1.3 cm sample width, 2.5 cm / min crosshead speed and 30 kg dynamometer. The results are shown in Tables 32 and 33 below.

Example 27 Wettability, vertical wicking and horizontal wicking data

Wetting, vertical wicking and leveling of sheets of various densities (0.15g / cm ³ , 0.30g / cm ³ and 0.45g / cm ³ ) prepared from pulp produced from modified cellulose of the present disclosure The wicking is compared with sheets made from self-study pulp. With Materials Testing Service of Kalamazoo, Ml uses its own testing equipment and procedures to carry out the tests.

Ten 50 cm ² samples were used to determine the required wettability characteristics. The results are shown in Tables 34-36 below.

Ten samples and a probe reading time of 600 seconds were used to determine the vertical wicking characteristics. The results are shown in Tables 37-38 below.

A 10-sample, 600-second probe reading time, and a 30-ml dose were used to measure the horizontal wicking characteristics at 7 ml / sec. The results are shown in Table 39 below.

Example 28 Multilayer absorbent sheet

Five different air cloth multilayer sheets were prepared and cut into 200 4 × 8 inch rectangles. Different groups are marked as shown in Table 40.

It should be noted that using TQ-2021 for conventional sheets and TQ-2028 for modified sheets, both surfactants are supplied by Ashland.

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, use standard laboratory filter paper to wet for another 2 minutes. The product has the characteristics shown in Tables 41 and 42.

Use 10 6.0cm × 16.0cm samples and 600 seconds pin reading time to test the synthetic urine wicking ability of the product. With Materials Testing Service of Kalamazoo, Ml uses its own testing equipment and procedures to carry out the tests. The results are shown in Tables 43 and 44 below.

Use the 9.0cm × 20.3cm cut sample to test the re-wetting of the product using the drop tube method and a 10ml 0.9% saline solution dosage using the Materials Testing Service. The results are shown in Table 45.

In the machine direction, 10 samples, 5.00 cm gauge length, 1.3 cm sample width, 2.5 cm / min cross head speed and 30 kg dynamometer were used to determine the wet tensile strength of each product (Materials Testing Service). The results are shown in Table 46 below.

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

Other inventive embodiments

Although the applicant's current desired invention is defined in the scope of the accompanying patent application, it should be understood that the present invention can also be defined according to the following embodiments, which are not necessarily excluded or limited to the claimed other embodiments:

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

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

C. A fiber derived from bleached hardwood kraft pulp, wherein the average fiber length of the fiber is 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 between about Between 0.75mm and about 1.25mm.

D. A fiber derived from bleached softwood kraft paper 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 of between about 85 to about 95 brightness.

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

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

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

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

I. The fiber 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 not greater than about 6 mPa‧s.

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

L. The fiber of any one 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 one of embodiments A to B and D to L, wherein the average fiber length is not greater than about 3.7 mm.

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

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

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

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

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

T. The fiber according to any one of embodiments A to S, wherein the fiber has between about 2 meq / 100g to about 8meq / 100g, preferably about 2meq / 100g to about 6meq / 100g, more preferably about 3meq / Carboxyl content between 100g and about 6meq / 100g.

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

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

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

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

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

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

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

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

CC. The fiber according to any one of embodiments A to BB, wherein the fiber has an aldehyde content between about 1 meq / 100 g to about 9 meq / 100 g, preferably about 1 meq / 100 g to about 3 meq / 100 g.

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

EE.

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

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

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

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

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

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

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

MM. The fiber of any one of embodiments A to MM, wherein the fiber has a carbonyl content as determined by a copper value greater than about 2, preferably greater than about 2.5, and more preferably greater than about 3, or as The carbonyl content determined by a copper value of about 2.5 to about 5.5, preferably about 3 to about 5.5, more preferably about 3 to about 5.5, or the fiber has a copper value as determined by a copper value of about 1 to about 4 The measured carbonyl content.

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

OO. 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.

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

QQ. The fiber according to any one of embodiments A to NN, wherein the total carbonyl content of the aldehyde The ratio is between about 0.8 to about 1.0.

RR. The fiber of any of the above 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, for example, at least about 720 mls or about 730 mls degree").

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

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

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

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

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

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

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

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

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

CCC. The fiber of any one of Embodiments A to WW, wherein the fiber has a fiber strength as measured by a wet zero-pitch break length of at least about 8 km.

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

EEE. The fiber of any one of embodiments A to WW, wherein the fiber has a fiber strength measured by a wet zero-distance break length between about 6 km and about 7 km.

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

GGG. The fiber of any of the above 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, more especially at least about 89 or about 90 ISO .

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

III. 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 through FFF, wherein the ISO brightness is at least about 89.

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

LLL. The fiber of any of the above embodiments, wherein the fiber has approximately the same length as standard kraft fiber.

MMM. The fiber of any of Examples A to S and SS to MMM, which has a higher carboxyl content than standard kraft fiber.

NNN. The fiber of any one of Examples A to S and SS to NNN, which has an aldehyde content higher than standard kraft fiber.

OOO. As in the fibers of Examples A to S and SS to MMM, the ratio of total aldehyde to carboxyl content is greater than about 0.3, preferably greater than about 0.5, more preferably greater than about 1.4 or, for example, between about 0.3 to about 0.5 or between about 0.5 to about 1 or between about 1 to about 1.5.

PPP. The fiber according to any one of the above embodiments, which has a knot index higher than the standard kraft fiber, for example, the knot index is between about 1.3 to about 2.3, preferably about 1.7 to about 2.3, more preferably about 1.8 to about 2.3 or between about 2.0 to about 2.3.

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

RRR. The fiber according to any one of the above embodiments, which has a crystallinity index lower than that of the standard kraft fiber, for example, the crystallinity index is reduced by about 5% to about 20%, preferably about 10% relative to the standard kraft fiber Up to about 20%, better reduced by 15% to 20% relative to standard kraft fiber.

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

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

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

VVV. The fiber according to any one of the above embodiments, wherein the fiber reduces atmospheric ammonia concentration by at least 40%, preferably by at least about 50%, more preferably by at least about 60%, more specifically than standard kraft fiber. Said at least about 70% or more at least about 75%, more especially at least about 80% or more about 90%.

WWW. The fiber according to any one of the above embodiments, wherein the fiber absorbs about 5 ppm ammonia / gram fiber to about 10 ppm ammonia / gram fiber, preferably about 7 ppm ammonia / gram fiber to about 10 ppm ammonia / gram fiber, more preferably From about 8 ppm ammonia / gram fiber to about 10 ppm ammonia / gram fiber.

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

YYY. The fiber according to any of the above embodiments, wherein the copper value is less than 2, preferably Ground is less than 1.9, more preferably less than 1.8, more preferably less than 1.7.

ZZZ. The fiber according to any one of Embodiments A to YYY, having a Kappa value of about 0.1 to about 1, preferably about 0.1 to about 0.9, more preferably about 0.1 to about 0.8, for example about 0.1 to about 0.7 or about 0.1 to about 0.6 or about 0.1 to about 0.5, more preferably about 0.2 to about 0.5.

AAAA. The fiber according to any of the above embodiments, which has substantially the same hemicellulose content as the standard kraft fiber, for example, between about 16% and about 18% when the fiber is a cork fiber, or When the fiber is a hardwood fiber, it is between about 18% and about 25%.

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

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

DDDD. The fiber of any 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 above embodiments, wherein the fiber is more compressible and / or embossed than standard kraft fiber.

FFFF. The fiber of Examples A to OOO, 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 / cc density.

GGGG. The fiber of Examples A to OOO, wherein the fiber can be compressed to a density higher than the density of the standard kraft fiber by at least about 8%, especially higher than the density of the standard kraft fiber by between about 8% to about 16%, Preferably about 8% to about 10% or about 12% to about 16% higher, more preferably about 13% to about 16% higher, more preferably about 14% to about 16% higher, in particular About 15% to about 16% is higher.

This article has described many embodiments. However, it should be understood that various modifications can be made without departing from the spirit and scope of the invention. Therefore, other embodiments are within the scope of the following patent applications.

Claims (11)

A urine absorption product comprising: oxidized kraft fiber, which is produced by: bleaching cellulose kraft pulp using a multi-stage bleaching process; and using peroxide and contact during at least one stage of the multi-stage bleaching process The medium oxidizes the kraft pulp under acidic conditions, wherein the multi-stage bleaching process includes at least one chlorine bleaching stage after the oxidation stage, wherein the oxidized kraft fiber is treated with a surfactant; wherein the urine absorption product contains multiple An absorbent fiber layer, and wherein the oxidized kraft fiber is incorporated into at least the bottom layer; and the urine absorbent product is wicked at 45 degrees compared to the same absorbent product made from kraft fiber that has not undergone the oxidation stage There is at least a 10% improvement. The urine absorption product of claim 1 has an improvement of at least 15% in the 45 degree wicking. The urine absorption product of claim 1 has an improvement of at least 20% in the 45 degree wicking. The urine absorbent product of claim 1, wherein the urine absorbent product has a density of 0.1 g / cm ³ to about 0.45 g / cm ³ . The urine absorbent product of claim 1, wherein the urine absorbent product has a density of at least about 0.15 g / cm ³ . The urine absorbent product of claim 1, wherein the urine absorbent product has a density of at least about 0.25 g / cm ³ . The urine absorbent product of claim 1, wherein the urine absorbent product has a density of at least about 0.35 g / cm ³ . A urine absorption product as in claim 6, wherein the product has an increased absorption rate and capacity over a comparable product made using only standard kraft fiber. The urine absorbent product of claim 6, wherein the product has improved dimensional stability over equivalent products made using only standard kraft fiber. The urine absorption product of claim 1, wherein the retention of the product is improved as the basis weight and density of the oxidized fiber increase. The urine absorbent product of claim 10, wherein the basis weight of the fibers in the product is at least about 150 gms.