TWI767110B - Lyocell fiber with increased tendency to fibrillate - Google Patents

Abstract

The present invention provides a lyocell fiber with increased tendency to fibrillate, requiring a time of less than 80 minutes to obtain a 50° SR value according to ISO 5267-1:1999 while the reduction of the working capacity [cN/tex*%] at the 50° SR value is less than 50%, as well as a method for producing same and products comprising same.

Description

Lay fiber with increased fibrillation tendency

The present invention relates to a fibrillated fiber having an increased fibrillation tendency, a method for producing the same, and a product comprising the same.

Various types of fibers are used to make products such as wet wipes and tissue. Typically, such fibers do exhibit a high degree of fibrillation in order to be able to absorb other materials (eg, during use or to provide functionalized wet wipes). One example of fibers used in this field are cellulose-based fibers. For example, fibrillated regenerated cellulose fibers are used in wood pulp-containing blends in a so-called wet-laid process milled in a refiner well known to those skilled in the art. The product from this process can be used in many applications - such as wipes and tissue for cleaning and wiping and technical applications. The fibrillated fibers result in increased stability and improved absorption for cleaning purposes and reduced air permeability and porosity.

US 8187422 describes a blend with fibrillated fibrils-microfibers and pulp to optimize the cleaning performance of the final wet tissue product, resulting in increased opacity and porosity and improved end product softness. In this patent, it is shown that fibrillated fibers can be fibrillated in an aqueous medium with a low solids content using a disc refiner or similar device. Usually chemical pretreatment of the fibers to fibrillate the fibers without any chemical pretreatment consumes a lot of energy and time. US 8187422 discloses processing already fibrillated fibers (obtained from external suppliers) to produce disposable wet wipes containing 25 to 75% of these fibrillated fibers.

US 6042769 shows examples of chemical treatments that enhance the tendency to fibrillation. It reveals a chemical treatment that reduces the DP (degree of polymerization) by 200 units, thereby tending to increase fibrillation. The chemical treatment mentioned in this patent refers to the use of bleaching agents such as sodium hypochlorite or mineral acids such as hydrochloric acid, sulfuric acid or nitric acid. So far, the commercialization of this procedure has not been successful.

US 9222222 discloses blends of lye fibers and low DP or standard DP cellulosic wood pulp fibers with a CSF (Canadian Standard Freeness) of 250ml or less, maintaining the CSF value even after drying. Wood pulp fibers comprise 10 to 75% of the total weight of fibers in the mixture. The low DP wood pulp contains a higher amount of hemicellulose, but is only added to the mixture in the form of the low DP wood pulp without mentioning any relevance of the hemicellulose content.

The fibrillation tendency was measured using the CSF method (Canadian Freeness Standard) according to TAPPI Standard T227 om-94. US 2015//0184338 A1 discloses compositions comprising kraft pulp. These are described as having low hemicellulose content. For example, the pulp is chemically pretreated with bleaching agents and/or acids. WO 99/47733 describes fibrous fibres and compositions for their preparation. WO2011/079331 A1, WO 01/81664 A1, WO 2014/161018 A1 and WO 2016/1977156 A1 disclose technical background information on cellulose fibers and compositions that can be used to prepare such fibers.

WO 2016065377 describes a wet tissue containing 5 to 20% by weight of rapidly fibrillated fibrillated fibers produced by chemical treatment with mineral acids. This fiber is characterized by very rapid fibrillation. During lapping, this rapid fibrillation is not always feasible. While standard Lay fibers tend to fibrillate too slowly, this fiber fibrillates too quickly. Furthermore, it must be taken into account that chemical treatment-induced fibrillation has an adverse effect on fiber properties. US 6706237 discloses that meltblown fibers obtained from hemicellulose-rich wood pulp show a reduced tendency towards fibrillation. US 8420004 discloses another example of meltblown fibers for making nonwoven fabrics.

Zhang et al. (Polymer Engineering and Science, 2007, 47, 702-706) describe fibers with higher hemicellulose content. The authors hypothesized that the fibers tended to exhibit enhanced fibrinofibrotic capacity, lower crystallinity, and better dyeability. They also hypothesized that tensile strength was only slightly reduced and that higher hemicellulose concentrations in the spinning dope could further improve fiber properties. Zhang et al. (Journal of Applied Polymer Science, 2008, 107, 636-641), Zhang et al. (Polymer Materials Science and Engineering, 2008, 24, 11, 99-102) disclosed and Zhang (Polymer Engineering and Science, 2007, 47, 702-706) the same figure, while Zhang et al. (China Synthetic Fiber Industry, 2008, 31, 2, 24-27) describe better mechanical properties. The same authors postulate the same theory in Journal of Applied Science, 2009, 113, 150-156. object of the present invention

In view of the increasing demand for fibers based on cellulose raw materials suitable for products such as wet tissue and tissue, it is expected that as described in WO 2016065377 and US 6042769, it can be obtained between standard fibrillated fibers and fast fibrillated fibers. A well-balanced fiber with a tendency to fibrillate fibers. At the same time, it would be beneficial if the chemical pretreatments disclosed in the prior art that are necessary to achieve the desired fibrillation tendencies could be avoided, since these would increase the cost of the final product and reduce the mechanical properties, the fibers obtained are not always is suitable for all desired applications. It was therefore the task of the inventors to provide fibers that can be fibrillated in a cost-effective manner while maintaining most of their working capacity to obtain good mechanical properties of wet wipes. Furthermore, some specific instances require well-balanced fibrillation mechanics during the refining process. In many nonwoven applications, there is a need for rapidly fibrillating fibers with good fiber properties because it makes processing of the fibers easier and results in improved strength and porosity properties of wet wipes.

Therefore, the inventors provide the fiber as defined in the 1st claim of the patentable scope, the fiber manufacturing method as defined in the 11th of the patented scope, and the product containing the fiber as defined in the 16th of the patented scope, and as Uses as defined in Scope Item 8. Preferred specific examples are described in the scope and specification of each dependent application.

In particular, the present invention provides the following specific examples, which are further explained and illustrated below. 1.) A non-chemically treated fibrillated fiber whose fibrillation tendency is increased, it takes less than 80 minutes to obtain a 50° SR value according to ISO 5267-1:1999, and work at this 50° SR value The reduction in capacity [cN/tex*%] is less than 50%. 2.) Lay fiber as in Example 1, wherein the time required to obtain the 50° SR value is shorter than 60 minutes but longer than 40 minutes. 3.) The fiber of the embodiment 1 and/or 2, wherein the reduction of the working capacity is less than 40%, preferably less than 30%. 4.) Lay fiber as in any one of specific examples 1 to 3, which has a denier of 9 dtex or less, such as 6 dtex or less, preferably 3 dtex or less. 5.) The fibrous fiber of any one of Embodiments 1 to 4, which is manufactured from wood pulp having a hemicellulose content of 7% by weight or more and 25% by weight or less. 6.) The fibrous fiber of embodiment 5, wherein the hemicellulose comprises a C5/xylan (xylan) to C6/mannan (mannan) ratio of 125:1 to 1:3, preferably 25: 1 to 1:2. 7.) The fiber of any one of embodiment 5 or 6, wherein the wood pulp comprises 5% by weight or higher xylan, preferably 8% by weight or higher, more preferably 10% by weight or more and/or 3 wt% or more mannans, preferably 5 wt% or more mannans, and/or 1 wt% or less mannans. 8.) A use of wood pulp to manufacture the fibers of any one of specific examples 1 to 7, wherein the wood pulp has a hemicellulose content of 7 wt% or more and 25 wt% or less. 9.) Use as in embodiment 8, wherein the hemicellulose comprises a C5/xylan to C6/mannan ratio of 125:1 to 1:3, preferably 25:1 to 1:2. 10.) The purposes of any one of specific examples 8 or 9, wherein the wood pulp comprises 5% by weight or more of xylan, preferably 8% by weight or more, more preferably 10% by weight or more High and/or 3 wt% or more mannans, preferably 5 wt% or more mannans, and/or 1 wt% or less mannans. 11.) A method of manufacturing the fibrous fiber as any one of specific examples 1 to 7, which utilizes a direct dissolution process. 12.) The method for producing fibrous fibers as in embodiment 11, which utilizes an amine oxide process, wherein the aqueous solution of amine oxide and the wood pulp form a cellulose suspension and a shapeable solution, The formable solution is formed and coagulated in a spin bath from which the fibrous fibers are obtained after washing and pretreatment steps. 13.) The method for producing fibrous fibers as in Example 12, which utilizes aqueous tertiary amine oxide, preferably aqueous NMMO. 14.) The method for producing a fibrous fiber as in any one of specific examples 11 to 13, wherein the spinning solution contains more than 10% by weight based on the total weight of the cellulose and hemicellulose contained. Wood pulp with hemicellulose content. 15.) The fibrous fiber, use or method of any of the preceding embodiments, wherein the wood pulp has a scan viscosity of 300 to 440 ml/g. 16.) A product comprising a lyofibre fiber as in any one of Embodiments 1 to 7 or 15 or a fiber as produced in any one of Embodiments 11 to 15. 17.) The product of embodiment 16, wherein the product is a nonwoven fabric. 18.) The product of embodiment 16 and/or 17, which is selected from tissue and wet tissue. 19.) The product of specific example 16, wherein the product is a specialty paper. 20.) The product of embodiment 19, wherein the specialty paper is filter paper.

As defined in claim 1, the fibers according to the present invention are fibrillated fibers with increased fibrillation tendency that do not require chemical pretreatment. This chemical pretreatment step is exemplified as described in AT 515693 B1.

The fibrillation process is well known in the art and relates to cellulosic wood pulp or other cellulose-based feedstocks in polar solvents (eg, N-methylmorpholine N-oxide [NMMO, NMO] or ionic liquids) in the direct dissolution process. Commercially, this technology is used to manufacture a range of cellulosic staple fibers (commercially available from Lenzing AG, Lenzing, Austria under the registered trademark TENCEL® or TENCEL™), which are widely used in the textile and nonwoven industries. Other cellulose bodies from Layfiber Technology have also been produced.

According to this method, the solution of the cellulose is extruded by means of a forming machine in a so-called wet and dry spinning process, and the moulding solution is guided, for example through an air gap, into a precipitation bath, where it is precipitated by the cellulose A molded body is obtained. After further processing steps, the mouldings are washed and optionally dried.

Such fibrous fibres are well known in the art and their general method of manufacture is for example disclosed in US 4,246,221 and analysed in BISFA (International Bureau for Standardisation of Man-Made Fibres) publication " Terminology of Man-Made Fibres ", 2009 edition . Both references are incorporated herein by reference.

The term fibrous fiber as used herein defines the fibers obtained by this process, since it has been found that fibers according to the present invention differ from fibers obtained, for example, from a meltblown process, even when utilized with cellulosic wood pulp or other cellulose-based The same is true for the direct dissolution process of the main starting materials in polar solvents such as N-methylmorpholine N-oxide [NMMO, NMO] or ionic liquids to make starting materials.

The term hemicellulose, as used herein, refers to materials known to those skilled in the art that are present in wood and other cellulosic feedstocks, such as annual plants, ie, feedstocks from which cellulose is typically obtained. Hemicellulose is present in wood and other plants in the form of branched short-chain polysaccharides composed of pentose and/or hexose (C5 and/or C6-sugar units). The main building blocks are mannose, xylose, glucose, rhamnose and galactose. The backbone of the polysaccharide may consist of a single unit (eg xylan) or two or more units (eg mannan). The side chain consists of arabinosyl, acetyl, galactosyl and O-acetyl and 4-O-methylglucuronic acid groups. The precise hemicellulose structure varies significantly within wood species. Due to the presence of side chains, hemicellulose exhibits much lower crystallinity than cellulose. It is well known that mannan is mainly bound to cellulose and xylan is bound to lignin. In conclusion, hemicellulose affects the hydrophilicity, accessibility and degradation properties of cellulose-lignin aggregates. During the processing of wood and wood pulp, the side chains are cleaved and the degree of polymerization is reduced. Known to those skilled in the art and as used herein the term hemicellulose includes hemicellulose in its natural state, hemicellulose degraded by ordinary processing and chemically modified by special process steps such as derivatization of hemicellulose and short-chain cellulose and other short-chain polysaccharides with a degree of polymerization (DP) up to 500.

The preferred wood pulps for use in the present invention do exhibit high levels of hemicellulose as described herein. The preferred wood pulp used in accordance with the present invention does also exhibit other differences compared to the standard low hemicellulose content wood pulp used to make standard lye fibers, these differences are summarized below.

Compared to standard wood pulp, the wood pulp used herein exhibits a more fluffy appearance, which is present in a high proportion of larger particles after milling (during the preparation of the starting material for forming the spinning solution for the fibrous process). produced below. As a result, the overall density is much lower than standard wood pulp with low hemicellulose content. This low overall density requires compliance with dose parameters (eg doses from at least two storage devices). Furthermore, the wood pulp used according to the present invention is more difficult to impregnate with NMMO. This can be seen by evaluating the impregnation properties according to Cobb's estimation method. Although standard wood pulps generally have a Cobb value greater than 2.8 g/g (determined according to DIN EN ISO 535, compliant with 78% NMMO in water at 75°C plus a soaking time of 2 minutes), the wood pulp used in the present invention did Shows a Cobb value of about 2.3 g/g. This requires adjustments during spinning solution preparation, such as increased dissolution time (eg as explained in WO 9428214 and WO 9633934) and/or temperature and/or increased burn during dissolution (eg WO 9633221, WO 9805702 and WO 9428217 ). This ensures the preparation of spinning solutions such that the wood pulps described herein can be used in standard fibrous spinning processes.

In a preferred embodiment of the present invention, the scanning viscosity of the wood pulp used for the preparation of fiber products, preferably fibers, as described herein is in the range of 300 to 440 ml/g, especially 320 to 420 ml/g. g, more preferably in the range of 320 to 400 ml/g. The scanning viscosity is determined according to SCAN-CM 15:99 in a cupriethylenediamine solution, which method is known to those skilled in the art and can be carried out on commercially available equipment, such as Apparatus Auto PulpIVA PSLRheotek purchased from psl-rheotek. The scanned viscosity is an important parameter affecting especially the processing of the wood pulp to prepare spinning solutions. Even though the two-wood pulp appears to be very similar to the raw material for this fibrous process, the different scanning viscosities will result in completely different behavior during processing. In a direct solvent spinning process like the Lay fiber process, the wood pulp is dissolved in NMMO as-is. Compared to the mucilage silk process, there is no maturation step, wherein the degree of polymerization of the cellulose is adjusted according to the needs of the process. Therefore, the viscosity specification of the raw wood pulp is usually within a small range. Otherwise, problems during production may occur. According to the present invention, it has been found to be beneficial if the pulp viscosity is as defined above. Lower viscosity will impair the mechanical properties of the fiber product. In particular, a higher viscosity may result in a higher viscosity of the spinning dope and therefore a slower spinning speed. With slower spinning speeds, lower draw ratios are obtained, which significantly alter the fiber structure and its properties (Carbohydrate Polymers 2018, 181, 893-901; Structural analysis of Ioncell-F fibres from birch wood, Shirin Asaadia; Michael Hummel; Patrik Ahvenainen; Marta Gubitosic; Ulf Olsson, Herbert Sixta). This will require process adjustments and will result in a reduction in equipment capacity. Smooth processing and production of high quality products can be achieved with wood pulp having the viscosities defined herein.

As used herein, the terms fiberizing process and fiberizing technology refer to cellulosic wood pulp or other cellulose-based feedstocks in polar solvents such as N-methylmorpholine N-oxide [NMMO, NMO] or Direct dissolution process in ionic liquid). This technology is used to manufacture a range of cellulosic staple fibers (commercially available under the registered trademark TENCEL® or TENCEL™ from Lenzing AG, Lenzing, Austria), which are widely used in the textile and nonwoven industries. Other cellulose bodies from Layfiber Technology have also been produced. According to this method, the solution of the cellulose is extruded by means of a forming machine, usually in a so-called wet-dry spinning process, and the moulding solution is led, for example through an air gap, into a precipitation bath, where it is carried by the cellulose Precipitation yields molded bodies. After further processing steps, the mouldings are washed and optionally dried. Processes for the manufacture of fibrous fibers are described, for example, in US 4,246,221, WO 93/19230, WO 95/02082 or WO 97/38153. Until this case discusses the disadvantages associated with the prior art and the unique properties of the novel products disclosed and claimed herein, in the use of laboratory equipment (especially in the prior art) or (semi-industrial) pilot equipment and commercial fiber spinning units In this context, the present invention should be understood in relation to larger scale plants/units, the following can be considered with regard to their respective production capacities: Semi-industrial test equipment about 1 kt/a Industrial equipment >30 kt/a

The above-mentioned task is solved by the fibrillation tendency of lyophilized fibers, which are produced without any chemical pretreatment. The chemical pretreatment step impairs the fiber properties (working capacity) on the one hand and increases the cost of the fiber manufacture on the other hand. Furthermore, the fibers according to the present invention show well-balanced fibrillation mechanics between standard fibrillated fibers and fast fibrillated fibers obtained by additional chemical pretreatment.

Thus, the fibrillated fibers according to the present invention avoid the need for chemical pretreatment while achieving rapid fibrillation.

Standard Layfiber fibers are currently produced industrially from high quality wood pulp, such as hemicellulose, with high alpha-cellulose content and low non-cellulose content. Commercially available lye fibers, such as TENCEL™ fibers produced by Lenzing AG, exhibit excellent fiber properties for nonwoven and textile applications.

As mentioned in the above-mentioned patents, if a high fibrillation tendency is desired, these fibrous fibers are chemically pretreated using, for example, mineral acids or bleaching agents. The fiber properties are drastically weakened and the working capacity is reduced by this chemical treatment.

The present invention overcomes the shortcomings of the prior art by providing the lyofibre fibers described herein.

Preferably, these are made from hemicellulose-rich wood pulp having a hemicellulose content of at least 7% by weight. Contrary to the disclosures of the prior art discussed above, it is surprising that for lyofibre fibers according to the definitions provided herein, this high hemicellulose content produces an increased tendency to fibrillation, while the mechanical properties of the fibers are only has a small impact. At the same time, this enhanced fibrillation tendency does not require chemical treatments that have been considered necessary in the prior art. Thus, the present invention surprisingly achieves the tasks described above while using a cellulose-based feedstock with a higher hemicellulose content compared to standard lysate fibers. Since the present invention does not require the use of chemical pretreatment to achieve the desired fibrillation, the reduction in mechanical fiber properties associated with the prior art can be overcome.

As mentioned above, Zhang et al. (Polym. Engin. Sci., 2007, 47, 702-706) describe fibers with higher hemicellulose content. The authors hypothesized that the received fibers tended to show enhanced fibrotic capacity for fibrinogenesis.

The fibers were analyzed for fibrillation tendency according to ISO 5267-1:1999 - Determination of drainage - Part 1: Schopper-Riegler (SR) method. The SR method provides drainage velocity ratings for diluted cellulosic fiber suspensions. Surprisingly, the present invention provides fibers with completely different properties, since the higher hemicellulose content results in a dramatic increase in the tendency for fibrillation. One possible explanation for these comparative results might be that the fibers according to the present invention were produced using large-scale production equipment, whereas the Zhang et al. ratio, production speed and post-processing do not reflect scale-up quality) manufactured by laboratory equipment for the manufacture of lyofibre fibers. Thus, fibers made without adequate drawing and adequate post-treatment exhibit different structures and properties than fibers produced on a production scale at deniers reflecting market applications.

The fibers according to the invention are produced by means of semi-industrial pilot plants (approximately 1 kt/a) and quasi-complete industrial post-processing of the fibers. Direct scale-up from this manufacturing cell to an industrial cell (> 30 kt/a) is feasible and reliable.

The hemicellulose content can be adjusted according to procedures known in the art. The hemicellulose can be hemicellulose derived from the wood from which the wood pulp is obtained, but individual hemicelluloses can also be added to high-purity cellulose with low virgin hemicellulose content depending on the fiber properties desired from other sources. The addition of individual hemicelluloses can also be employed to adjust the composition of the hemicellulose content, for example to adjust the hexose to pentose ratio.

The wood pulp capable of producing fibers according to the invention preferably exhibits a C5/glycan to C6/mannan ratio of 125:1 to 1:3, preferably 25:1 to 1:2. The hemicellulose content may be 7 wt% or higher, preferably 10 wt% or higher, more preferably 14 wt% or higher, and in specific examples up to 25 wt% or even 30 wt%. In a specific example, in combination with or alone the aforementioned hemicellulose content, the xylan content is 5 wt% or more, such as 8 wt% or more, and in a specific example 10 wt% or more. In particular examples, either alone or in combination with the hemicellulose and/or xylan contents described above, the mannan content is 3 wt% or higher, eg, 5 wt% or higher. In other embodiments, the mannan content, preferably in combination with a high xylan content as defined above, may be 1 wt% or less, such as 0.2 wt% or 0.1 wt% or less.

As mentioned above, the hemicellulose content of the fibers of the present invention is generally higher than that of standard lay fibers. A suitable content is 5% by weight or more and up to 30% by weight. Preferably, fibers according to the present invention exhibit a C5/xylan to C6/mannan ratio of 125:1 to 1:3, preferably in the range of 25:1 to 1:2. With regard to the xylan and/or mannan content, the specific examples described above for wood pulp also apply to the fibers themselves.

Fibres according to the invention typically have a denier of 9 dtex or less, eg 3.3 dtex or less, eg 2.2 dtex, depending on the intended application. If the fibers are intended for nonwoven applications, a denier of 1.3 or higher, eg, 1.7 dtex, is generally suitable. However, the present invention also encompasses fibers having a much lower denier, with a suitable lower limit for denier being 0.5 dtex or higher, such as 0.8 dtex or higher, and in particular 1.3 dtex or higher. These upper and lower values disclosed herein define the range of 0.5 to 9 dtex, and include all other ranges formed by combining any one of the upper and lower values.

Fibers according to the present invention can be prepared according to standard spinning processes known to those skilled in the art using spinning techniques using cellulose solutions and spinning processes using precipitation baths. Furthermore, the fibers used do not require any known chemical pretreatment to enhance the fibrillation tendency, which typically reduces DP by several hundred since the present invention achieves the desired degree of fibrillation without such treatment. unit.

The fibers according to the present invention can be used in various applications, such as the manufacture of nonwoven fabrics. Examples of products include tissue, wet wipes, and specialty papers made by wet-laid and/or air-laid techniques (eg, filter paper applications). The fibers according to the invention can be used as the sole fibers of the desired product or they can be mixed with other types of fibers. The mixing ratio can depend on the desired end use. If, for example, wet wipes with improved mechanical properties are desired, the fibers according to the present invention may be present in higher amounts relative to other high-fiber fibers according to the prior art to ensure the desired mechanical properties, while other In applications, relatively low amounts of the fibers of the present invention may suffice.

As far as the parameters mentioned herein, eg crystallinity, scanning viscosity, etc. are concerned, it is understood that they are determined to be the same as outlined herein in the general section of the specification and/or as outlined in the examples below. In this regard, it should be understood that the parameter values and ranges defined herein with respect to fibers refer to the use of materials derived from wood pulp and containing only additives typically added to spinning dope (eg, processing aids) and other additives (eg, matting agents) (TiO ₂ , typically added in an amount of 0.75 wt %), with a total amount of up to 1 wt % (based on the fiber weight) of fibers measured for properties. The unique and special properties reported herein are properties of the fibers themselves, Rather than properties obtained by adding specific additives and/or post-spinning treatments (eg, fibrillation improvement treatments, etc.).

However, it will be clear to those of ordinary skill in the art that the fibers disclosed and claimed herein may contain conventional amounts of additives, such as inorganic fillers and the like, as long as the presence of such additives does not adversely affect dope preparation and spinning operations . The types of such additives and the respective amounts to be added are known to those skilled in the art. Example:

在Andritz實驗室設備12-1C磨片精研機(NFB，S01-218238)中以6 g/l、1400 rpm及172 l/min流速的起始濃度精研3種不同類型纖維。 間隙固定於1 mm。 精研結果舉例說明於圖1。可見到，與萊纖標準纖維相比，萊纖提昇的原纖化纖維及萊纖化學原纖化纖維以顯著更高的速率原纖化，這意指時間及能量的縮減。然而，該萊纖提昇的原纖化纖維顯示出原纖化的提昇比化學原纖化纖維更慢。 Example 1 : Comparison of fibrillation mechanics 3 different fiber types were compared: Standard 1.7 dtex/4 mm lye fibers are commercially available under the tradename TENCEL™ fibers from Lenzing AG ("the lye standard"). Lay fibers subjected to chemical pretreatment ("laid chemical fibrillation") were produced as described in WO 2016065377. Fiber tows with a single denier of 1.7 dtex were impregnated with dilute sulfuric acid in a liquid ratio of 1:10 at room temperature and then extruded to about 200% moisture. The fiber tow was post-treated in a steam cooker for about 10 minutes so that water vapor could be applied under pressure. The fiber bundles are acid-free cleaned, a softening agent is applied and the fibers are dried. The dried fiber tows were cut into 4 mm staple fibers, which were then terminated with 1.7 dtex/4 mm "laid-fiber chemical fiberized" fibers. "Lifted fibrillated" fibers are made from wood pulp rich in hemicellulose, with a hemicellulose content >10% (xylan, mannan, arabinan, ...), after A 1.7 dtex/4 mm "laid-lifted fibrillated" fiber was obtained after post-spinning treatment. The composition of the hemicellulose-enriched wood pulp is shown in Table 1 compared to the standard wood pulp used to make the fibrous fibers. Table 1: Comparison of different hemicellulose contents of wood pulp

3 different types of fibers were refined in an Andritz laboratory equipment 12-1C Disc Refiner (NFB, S01-218238) at starting concentrations of 6 g/l, 1400 rpm and a flow rate of 172 l/min. The gap is fixed at 1 mm. The refined results are illustrated in Figure 1. It can be seen that the fibrillated fibers raised and the chemical fibrillated fibers fibrillated at a significantly higher rate, which means a reduction in time and energy, compared to the standard fibers. However, the fiber-lifted fibrillated fibers showed a slower increase in fibrillation than chemical fibrillated fibers.

可見到該二纖維類型顯示出高的原纖化趨向。為了達成50°SR，二類型的纖維皆需要不到60分鐘的時間。 這也很明顯；然而，該化學處理對該纖維性質也有不利影響，因為該工作容量顯著降至其初始值的約60%。另一方面，根據本發明的纖維僅顯示輕微下降的工作容量，從而證明本發明萊纖提升的原纖化纖維的優越性。 於表4中，比較了不同纖維類型的CSF (根據TAPPI標準T227 om-94分析)的值。顯示混合8分鐘之後的CSF值。 該纖維係根據實施例1製造，切割長度為38 mm。該非織造纖維(NW)摻入0.75% TiO₂ 作為消光劑(dulling agent)。將用以製製該萊纖提昇的原纖化II的富含半纖維素的木漿之組成顯示於表3中。結果再次確證，根據本發明獲得原纖化趨向被提昇的萊纖纖維，而不需要化學處理而且也沒有先前技藝中與此處理相關的不利影響。 表3：用以製造萊纖提升的原纖化II的富含半纖維素的木漿之糖含量。

表4：不同纖維經過8分鐘的混合時間之後的CSF值之比較。

Example 2 : Comparison of fibrillation time and tenacity In Table 2, the time to reach 50°SR (analyzed according to ISO 5267-1:1999) and the fibrillated fibers lifted by the fibrillated fibers and the fibrillated chemical fibrils were compared Fiber toughness of chemical fibers. In the observed fibrillation window, the lye standard fiber did not achieve 50°SR. Table 2: Comparison of time to 50°SR and tenacity of fibers (working capacity determined according to the BISFA definition).

It can be seen that this difibrillar type shows a high tendency to fibrillation. To achieve 50°SR, both types of fibers require less than 60 minutes. This is also evident; however, the chemical treatment also had a detrimental effect on the fiber properties, as the working capacity was significantly reduced to about 60% of its initial value. On the other hand, the fibers according to the present invention show only a slightly reduced working capacity, thus demonstrating the superiority of the fibrillated fibers lifted by the present invention. In Table 4, the values of CSF (analyzed according to TAPPI standard T227 om-94) for different fiber types are compared. The CSF values after 8 minutes of mixing are shown. The fibers were made according to Example 1 with a cut length of 38 mm. The nonwoven fibers (NW) were incorporated with 0.75% _TiO2 as a dulling agent. The composition of the hemicellulose-rich wood pulp used to make the fibrillated raised fibrillation II is shown in Table 3. The results reconfirmed that, according to the present invention, fibrillated fibers with increased fibrillation tendencies are obtained without the need for chemical treatment and without the adverse effects associated with this treatment in the prior art. Table 3: Sugar content of hemicellulose-enriched wood pulp used to make fibrillated fibrillated II.

Table 4: Comparison of CSF values for different fibers after a mixing time of 8 minutes.

Figure 1 shows the fibrillation mechanics of fibres according to the present invention compared to standard fibres and fibres subjected to chemical fibrillation.

Claims (20)

A non-chemically treated Layfiber fiber with increased fibrillation tendency, which takes less than 80 minutes to obtain a 50° SR value in accordance with ISO 5267-1:1999, while the working capacity for this 50° SR value [cN /tex*%] is less than 50% and is made from wood pulp with a hemicellulose content of 14% by weight or more. As claimed in claim 1, the lyofiber fiber, wherein the time required to obtain the 50° SR value is shorter than 60 minutes but longer than 40 minutes. As for the lyofiber fiber of the first item of the patented scope, the reduction of the working capacity is less than 40%. The lyofibre fiber according to any one of items 1 to 3 of the claimed scope has 9dtex to 0.5dtex. As claimed in claim 1 of the patented scope, the fiber is made of wood pulp with a hemicellulose content of at most 30% by weight. The fiber of claim 5, wherein the hemicellulose comprises a ratio of C5/xylan to C6/mannan of 125:1 to 1:3. A use of wood pulp for the manufacture of lyofibre fibers as claimed in any one of claims 1 to 6, wherein the wood pulp has a hemicellulose content of 14 to 25% by weight. The use as claimed in claim 7, wherein the hemicellulose comprises a ratio of C5/xylan to C6/mannan of 25:1 to 1:2. A method for producing the fibrous fiber as claimed in any one of items 1 to 6 of the scope of the application, which utilizes a direct dissolution process. According to the method for producing fibrous fiber in item 9 of the scope of the application, it uses an amine oxide process, wherein the aqueous solution of amine oxide and the wood pulp form a cellulose suspension and can be A forming solution, the formable solution after washing and pretreatment steps is formed and coagulated in a spin bath from which the fibrous fibers are obtained. For example, the method for producing lyofiber in the 10th patent application scope utilizes water-based tertiary amine oxide. The method for producing a fibrous fiber according to any one of claims 9 to 11 of the claimed scope, wherein the spinning solution contains at most 25 wt % of hemicellulose based on the total weight of the cellulose and hemicellulose contained. Wood pulp with cellulose content. The fiber as claimed in any one of claims 1 to 3, wherein the wood pulp has a scan viscosity of 300 to 440 ml/g. The use of any one of claims 7 to 8 of the claimed scope, wherein the wood pulp has a scan viscosity of 300 to 440 ml/g. The method for producing fibrous fibers according to any one of claims 9 to 11 of the claimed scope, wherein the wood pulp has a scan viscosity of 300 to 440 ml/g. A product comprising a fiber as claimed in any one of claims 1 to 6 or 13 or a fiber produced by the method of any one of claims 9 to 12 or as claimed in claim 15 . Such as the product of claim 16, wherein the product is a non-woven fabric. For example, the product of claim 16 or 17 of the scope of the application is selected from tissue and wet tissue. Such as the product of item 16 of the scope of the application, wherein the product is special paper. As for the product of item 19 of the patent application scope, the special paper is filter paper.

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