BR112019020470A2 - natural fiber treatment process - Google Patents

Abstract

the invention relates to a process for treating natural fibers that allows them to be packed for the optimal production of yarns and subsequently of textile bases. the process comprises the steps of alkaline treatment, bleaching and the addition of a softening agent.

Description

PROCESS OF TREATING NATURAL FIBERS FIELD OF THE INVENTION [001] The present invention fits in the textile sector, particularly in processes of treatment of natural fibers for different applications.

BACKGROUND OF THE INVENTION [002] Currently, the leaves of the Aspargaceae family are considered a variety of fibrous plant materials with a high potential for exploitation in the textile industry. Generally, these plant materials have a high cellulose content that can be used in the manufacture of textile bases for clothing. However, its use as a raw material in the construction of textile bases is limited due to its low fineness and fiber roughness, due to the presence of non-cellulosic components, which does not make it suitable for obtaining threads that can be spun with machinery for the construction of textile bases.

[003] With the height of the study of new applications of Liberian natural fibers, the most recent advances have focused on developing cotonization processes, which refer to the processing of Liberian or hard fibers to make them similar to cotton fibers in terms of its properties (for example, length, smoothness, diameter or fineness). This cotonization is obtained by removing all or part of the pectins, lignin and hemicellulose without damaging the cellulose of the fiber and separating the elementary fibers that are joined to each other by these compounds.

[004] In the state of the art processes are described

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2/11 treatment of natural fibers from the families Poaceae, Urticaceae, Malvaceae, Linaceae, Gramineae, Fabaceae, Cannabaceae, with which fibers with different properties and characteristics are obtained. The processes that are disclosed generally include alkaline treatment, bleaching and drying steps.

[005] US7481843 B2 describes a procedure for the extraction and preparation of bast fibers from ramie (Urticaceae family), jute (Malvaceae family) and hemp (Cannabaceae family), with which fibers are obtained for the production of fine spun yarns , pure, in which the conventional spinning train is fed 100% with the selected fiber, or mixtures, in which, before the carding process different fibers are mixed in the desired proportions and, at the end of the spinning process, a yarn is obtained intimate blend spun.

[006] Document US5718802 discloses the use of the sugar cane by-product (family Poaceae) for the production of yarns and non-woven fabrics, in which, for the extraction of fibers, an alkaline treatment with NaOH (caustic soda) and temperature Is it used. Combined mechanical treatments are also used, such as steam explosion, gas bubbles under pressure, strong boiling, among others.

[007] The document US20070199669 discloses a method for the extraction of cellulosic fibers from leaves and stalks of corn, pasture, rice, barley (family Poaceae) sorghum, wheat, (family Gramineae), soybeans (family Fabaceae) and cotton stalks (Malvaceae family), using an alkaline treatment to partially delignify the material and a subsequent enzymatic treatment to extract

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3/11 the fibers.

[008] US 7624478 B2 describes a method for processing Liberian fibers derived from cotton stalk (Malvaceae family), which comprises extraction, degumming, preservation, cutting, opening, carding, sorting and packaging. US 7526837 B2 discloses a process for the treatment of flax fibers (Linaceae family), which consists of cleaning, cottoning, macerating and drying the raw material using an electro-hydraulic process.

[009] The document US 4359859 B2 describes a thread formed with the fibers of the leaves and the sheaths of corn, by immersing the leaves and sheaths in a solution of caustic soda to release them and subsequently dried, carded and spun. . CN101041916 (A); describes a process for obtaining a mixture yarn of bamboo fiber (family Poaceae) and ramie (family Urticaceae).

[010] In the extraction and preparation of fibers from the Aspargaceae family, improper processing can damage fibers to a great extent, generating low fiber yield and economic losses. Therefore, there is a need to design procedures for the extraction and preparation of fibers from the Aspargaceae family, which allow obtaining fibers suitable for the construction of high quality textiles for clothing.

[011] The process of the invention allows obtaining natural fibers for new textile bases for the diversification of their applications in clothing, expanding the portfolio of opportunities for these fibers within the textile world.

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BRIEF DESCRIPTION OF THE INVENTION [012] The process of the present invention allows to obtain modified natural fibers from the leaves of plants of the Aspargaceae family, by adding a softening agent to the natural fibers after they have been subjected to an alkaline and bleaching treatment. The obtained fibers exhibit excellent tactile properties due to the removal of non-cellulosic components, favoring a reduction in the diameter of the fibers and an increase in their flexibility.

BRIEF DESCRIPTION OF THE FIGURES [013] FIGURE 1. Photograph of the natural fiber (a) and the cotton fiber (b).

[014] FIGURE 2. Scanning electron microscope (SEM) images of natural fiber (a) and cotton fiber (b).

[015] FIGURE 3. Photograph of a cotton / cotton blend yarn (1: 1).

[016] FIGURE 4. Screen photograph produced with a cotton / pita blend yarn (1: 1).

DETAILED DESCRIPTION OF THE INVENTION [017] The hard fibers from the leaves of the plants of the Aspargaceae family are basically composed of cellulose (between 40% and 70%), hemicellulose, pectins and lignin, which are responsible for agglutinating and maintaining the integrity of the cellulosic fibers. These other non-cellulosic components are responsible for these fibers being rough, not very flexible and with low hygroscopicity. These components must be removed with chemical, mechanical, enzymatic

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5/11 and / or physical to obtain softer and individualized fibers with applications in the textile sector.

[018] Thus, the present invention relates to a process for the treatment of natural fibers from the Aspargaceae family, including pita, henequém and sisal, whose leaves and stems are initially shredded and the fibers cut lengthwise between sizes 10 mm and 1500 mm.

[019] Once the fibers are defibrated and cut, they are subjected to an alkaline treatment that consists of submerging them in an alkaline solution of KOH or NaOH (1% to 20% w / w), with a fiber / alkaline solution between 1: 5 and 1:50, at a temperature between 20 and 90 ° C, for 1 to 24 hours. In one embodiment of the process of the invention, the fibers are submerged in an alkaline solution of NaOH between 10% and 15% (w / v), at a fiber / solution ratio between 1:20 and 1:40, at a temperature between 60 ° C and 80 ° C for 1 to 5 hours. In another embodiment of the process of the invention, the fibers are submerged in a 15% (w / v) solution of KOH at a temperature of 80 ° C for 2 hours.

[020] The obtained fibers are rinsed one or more times with water and subjected to a bleaching phase, which can be carried out by chemical treatment or enzymatic treatment at a temperature between 20 ° C and 90 ° C, for 0.1 to 168 hours, after which the fibers are rinsed again with water. In one embodiment of the process of the invention, the bleaching phase is carried out by chemical treatment at a temperature between 60 ° C and 90 ° C, for 0.5 to 3 hours, preferably at a temperature of 80 ° C, for 2 hours.

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6/11 [021] For the purposes of the present invention, ο chemical treatment of the bleaching phase consists of adding to the fibers a bleaching agent, a strong base, a catalyst and a defoamer. The bleaching agent is selected from chemical compounds like chlorine in any state, compounds and / or salts derived from chlorine (eg sodium hypochlorite), sulfides or sulfuric compounds, oxygen or ozone or compounds that release oxygen such as peroxides, perborates , persulfates or perchlorates, alkali metals, alkaline earth metals, composed of ammonium, and mixtures thereof, in concentrations ranging from 1% to 30% (w / v). In one embodiment of the invention, the bleaching agent is hydrogen peroxide.

[022] The strong base that is added in the bleaching phase can be NaOH or KOH, at concentrations between 0.1 and 5% (w / w); the catalyst is selected from inorganic salts, hydrocarbons, alcohols, organic acids and their derivatives, in concentrations between 0.01% and 1.0%; and the defoaming agent is selected from siliconized, non-siliconized emulsions or stearic derivatives of alcohols or siloxanes, in concentrations of 1.0% to 10.0%. In one embodiment of the process of the invention, the strong base is NaOH, the catalyst is magnesium sulfate, the bleaching agent is hydrogen peroxide and the defoamer is a stearic alcohol.

[023] The enzymatic bleaching treatment consists of adding to the natural fibers one or more enzymes such as: peroxidases, laccases, oxidases catalases, pectinases, cellulases, at concentrations between 1 and 100 g / L, at a temperature between 20 and 60 ° C, between 1 and 168 hours. In

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7/11 a modality of the invention, the enzymatic treatment is carried out by adding peroxidases and cellulases at a concentration between 0.01% and 5% (v / v) at a temperature between 20 ° C and 40 ° C, for 1 to 168 hours. In another embodiment of the invention, the enzymatic treatment is carried out by adding peroxidase at a concentration of 0.3 (v / v), temperature of 25 ° C, for 168 hours.

[024] Once the bleaching phase is complete, a softening agent is added to the fibers, which is selected from cationic, anionic, non-ionic, reactive, amphoteric, siliconized or enzymatic emulsions, in order to smooth the fiber and to avoid hornification of cellulose, which would hinder the carding process, in which the fiber is opened, separated and cleaned of dirt and short fibers, in order to be individualized and parallelized to form a veil that will be converted into a card at the end of the process.

[025] The smoothing agent at a concentration between 0.1% and 10%, preferably between 0.5% and 2.0%, and is added to the fibers at a temperature between 30 ° C and 80 ° C, with a ratio fiber / solution between 1: 5 and 1:50 and for a period of time between 0.5 and 2 hours. In one embodiment of the invention the smoothing agent is a siliconized nanoemulsion at a concentration of 1.0%, the fiber / solution ratio is 1:40, the temperature is 60 ° C, for one hour.

[026] Finally, the fibers can be subjected to a drying step, which can be carried out at room temperature (15 ° C to 25 ° C) or by convection in an oven at a temperature between 40 ° C and 80 ° C for 0.5 to 36 hours.

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8/11 [027] The fibers obtained by the process of the invention have characteristics similar to cotton fiber, such as soft feel, white color, greater flexibility and fineness. For having these characteristics, the fiber can be intimately mixed with other fibers such as cotton, and with all types of artificial and synthetic fibers in the production of fine threads, which facilitate the production of textile bases that can be used in garments, accessories , tapestry and decoration in general.

[028] The following Examples illustrate the invention without the concept of the invention being restricted to them.

Example 1. Treatment of pita fibers [029] Pita fibers of a length of 35mm were cut with a guillotine. The fibers were subjected to an alkaline process at 80 ° C for 2 hours, using a solution of 666.6 g of potassium hydroxide and 3333.3 ml of water.

[030] Subsequently the fibers were rinsed and the bleaching phase was carried out, in which 2918 ml of water, 80 g of caustic soda in a concentration of 90%, 2.0 g of magnesium sulphate, 200 g of defoamer (stearic alcohol) and 800 g of hydrogen peroxide in a concentration of 10% (w / w).

[031] The obtained solution was brought to a temperature of 80 ° C, maintained for one hour and afterwards the fibers were rinsed 3 times by overflow. Finally, the fiber was subjected to a smoothing process, for which a solution was prepared with 3920 ml of water and 80 g of a siliconized nanoemulsion. This solution was brought to a temperature of 60 ° C to add

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9/11 the fiber and subject it to that process for one hour. The resulting cotton fiber was dried in an oven at 40 ° C for 24 hours.

Example 2. Treatment of Pita fibers [032] Pita fibers of a length of 35mm were cut with a guillotine. The fibers were subjected to an alkaline process at 60 ° C for 0.5 hours, using a solution of 222.2 g of potassium hydroxide and 3777.7 ml of water.

[033] Subsequently, the fibers were rinsed and the bleaching phase was carried out, in which 2918 ml of water, 80 g of caustic soda in a concentration of 90%, 2.0 g of magnesium sulphate, 200 g of defoamer (stearic alcohol) and 800 g of hydrogen peroxide in a concentration of 10% (w / w).

[034] The obtained solution was brought to a temperature of 80 ° C, maintained for one hour and afterwards the fibers were rinsed 3 times by overflow. Finally, the fiber was subjected to a smoothing process, for which a solution was prepared with 3920 ml of water and 80 g of a siliconized nanoemulsion. This solution was brought to a temperature of 60 ° C to add the fiber and subject it to this process for one hour. The resulting cotton fiber was dried in an oven at 40 ° C for 24 hours.

Example 3. Treatment of Sisal fibers [035] Sisal fibers of a length of 35mm were cut with a guillotine. The fibers were subjected to an alkaline process at 80 ° C for 2 hours, for which a solution of 666.6 g of hydroxide was used

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10/11 potassium and 3333.3 ml of water.

[036] Subsequently the fibers were rinsed and the bleaching phase was carried out, in which 2918 ml of water, 80 g of caustic soda in a concentration of 90%, 2.0 g of magnesium sulfate, 200 g were added

of defoamer (stearic alcohol) and 800 g of peroxide in hydrogen in a concentration of 10 % (w / w) · [037] A solution obtained was taken The an temperature 80 ° C, maintained during a hour and

subsequently the fibers were rinsed 3 times by overflow. Finally, the fiber was subjected to a smoothing process, for which a solution was prepared with 3920 ml of water and 80 g of a siliconized nanoemulsion. This solution was brought to a temperature of 60 ° C to add the fiber and subject it to this process for 1 hour. The resulting cotton fiber was dried in an oven at 40 ° C for 24 hours.

Example 4. Pita fiber characterization [038] The following characterization tests were carried out with the pita fibers obtained according to Example 1: length, diameter, tensile strength, final lignin content, final cellulose content, final content hemicellulose (Table 1).

Table 1

Property Banner Longitude 20 - 35 mm Fineness / Diameter 54 - 125 mm Tensile strength 48 - 257 MPa Lignin content 4.2 - 7.6% Cellulose content 60 - 80% Hemicellulose content 0.0% - 13.5%

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Example 5. Obtaining yarn from Pita fibers [039] From the pita fibers obtained according to Example 1, a spun yarn with a cotton / cotton composition (1: 1) was developed. For the development of this thread, a 28 mm cotton with a fineness of 3.6 micronaire was selected. The fibers were mixed in a 50/50 ratio, passed through the opening process in a Shirley opener and carding, in which fixed flat cards were used.

[040] The brace in card was last 3 times consecutive by the dowel to in regular the mass of brace, which had a grammage in 3.3 g / m. The belt

The resulting dowel was processed in an industrial electro-jet roving frame to obtain a 0.850 g / m wick. Finally, a wire from a cable was obtained in a pinter ring spinning machine with a 520 twist / meter Z twist with a Ne 14 title.

Example 6. Obtaining a textile base [041] From yarns obtained according to Example 5, a textile base was obtained which was produced on a Jacquard loom. The loom, previously woven with a polyester cotton blend yarn and a cotton wool / cotton pita (1: 1), was inserted into the weft. Flat fabric was produced in the taffeta, twill and satin ligaments.

Claims (13)

1. Process for treating natural fibers CHARACTERIZED by the fact that it comprises the following steps: a) subject the natural fibers to an alkaline treatment; b) subjecting the fibers obtained in (a) to a bleaching phase; and c) add a softening agent to the fibers obtained in step (b). 2. Process, according to claim 1, CHARACTERIZED by the fact that the natural fibers are from the Aspargaceae family. 3. Process, according to claim 2, CHARACTERIZED by the fact that natural fibers are selected from sisal, pita, henequém and abaca. 4. Process, according to claim 1, CHARACTERIZED by the fact that the alkaline treatment of step (a) is carried out by incorporating the natural fibers in a 15% (w / v) NaOH or KOH solution a a temperature between 25 ° C and 100 ° C and a period of time between 0.1 and 24 hours. 5. Process, according to claim 1, CHARACTERIZED by the fact that the bleaching phase of step (b) is carried out by chemical treatment or enzymatic treatment. 6. Process according to claim 1, CHARACTERIZED by the fact that the bleaching step of step (b) is carried out by adding a defoaming agent, a strong base, a catalyst and an agent Petition 870190107175, of 10/22/2019, p. 5/10 2/3 bleach, maintaining a temperature between 20 ° C and 100 ° C, for a period of time between 0.1 and 24 hours. 7. Process, according to claim 6, CHARACTERIZED by the fact that the defoaming agent is a stearic derivative of alcohols or siloxanes, the strong base is NaOH or KOH. 8. Process, according to claim 6, CHARACTERIZED by the fact that the catalyst is selected from inorganic salts, hydrocarbons, alcohols, organic acids and their derivatives. 9. Process according to claim 6, CHARACTERIZED by the fact that the bleaching agent is selected from hydrogen peroxide, sodium chlorite, sodium hypochlorite and mixtures thereof. 10. Process, according to claim 1, CHARACTERIZED by the fact that the bleaching process of step (b) is carried out by means of an enzymatic treatment that consists of adding at least one ligninolytic enzyme selected from peroxidases, oxidases, laccases and mixtures thereof, at a temperature between 20 ° C and 80 ° C for 0.1 to 168 hours. 11. Process, according to claim 1, CHARACTERIZED by the fact that the smoothing agent of step (c) is selected from silicones, silicone emulsions, silicone nanoemulsions, ligninolytic enzymes and mixtures thereof. 12. Process according to claim 1, CHARACTERIZED by the fact that it additionally comprises a drying step, carried out at a temperature between 15 ° C and 80 ° C. Petition 870190107175, of 10/22/2019, p. 6/10 3/3 13. Natural fibers obtained according to the process of claims 1 to 12, CHARACTERIZED by the fact that they have the following properties: Property Banner Longitude 20 - 35 mm Fineness / Diameter 54 - 125 mm Tensile strength 48 - 257 MPa Lignin content o \ ° CD 1 C \ 1 Cellulose content 60 - 80% Hemicellulose content 0.0 - 13.5% Petition 870190107175, of 10/22/2019, p. 7/10