CN1793484A - Process for preparing modified cotton fibre - Google Patents

Abstract

The invention relates to a preparation method of modified cotton fiber, which belongs to the modification technology of textile fiber materials. The method is as follows: first scouring and bleaching the twisted cotton yarn; then placing the cotton yarn in a solution with a periodate concentration of 0.1 to 3 g/L for selective oxidation reaction treatment, and the temperature of the reaction solution is 30-60°C, the treatment time is 1-2 hours; then, remove the oxidant on the cotton fiber, fully wash with clean water, dehydrate, and dry to obtain the oxidized cotton fiber whose strength and elongation decrease rate is less than 25%; use molecular chain Substances with -NH ₂ and -OH active groups can be grafted and cross-linked to modify cotton fibers to prepare functional and multifunctional composite cotton fibers, which improves the wearability and added value of cotton fibers , greatly expanded the application field of cotton fiber, and effectively solved the functionalization problem of cotton fiber from the field of textile fiber raw materials.

Description

A kind of preparation method of modified cotton fiber

Technical field

The invention relates to a preparation method of modified cotton fiber, which belongs to the modification technology of textile fiber materials.

Background technique

Cotton fiber is one of the abundant renewable resources in nature, and its application involves various fields such as new materials, chemical raw materials, national defense, food, medicine, and environment. Cotton fiber is a linear semi-rigid natural polymer compound formed by D-glucopyranose anhydride linked by β-1,4-glycosidic bonds. There are 3 active hydroxyl groups on each glucosyl ring in its macromolecular chain ( two secondary hydroxyl groups and one primary hydroxyl group). As a natural cellulose fiber, cotton fiber has the characteristics of good hygroscopicity, air permeability, warmth retention, antistatic property and soft hand feeling, and plays an important role in the field of textile fiber materials. However, cotton fiber itself also has many shortcomings, such as poor wrinkle resistance, easy shrinkage after washing, poor antibacterial properties, and single function; with the continuous rise of high-performance, multi-functional synthetic fibers and other textile materials, cotton fibers have created a huge shock. In order to fully develop the potential functions of cotton fibers and improve the performance of cotton fibers, various methods of modification of cotton fibers have become a hot research direction in countries all over the world.

At present, there are mainly two ways in the chemical modification technology of cotton fiber. One is to use chemical reagents to directly modify the cotton fiber, and to improve its performance by changing the structure of the cotton fiber. For example, after mercerizing cotton fibers with caustic soda, "mercerized cotton" can be prepared. Resins or polycarboxylic acids are used for anti-wrinkle and non-ironing finishing of cotton fabrics, etc. Before the present invention was made, Chinese patent CN1039456 disclosed a process of polycarboxylic acid for formaldehyde-free durable pressing of cotton fabrics, that is, when the temperature is raised by heating, the polycarboxylic acid and the cellulose in the textile act as a catalyst Under this condition, the esterification and crosslinking reactions occur rapidly, and the wrinkle resistance and non-ironing properties of cotton fabrics are improved after treatment. This modification method plays a certain role in improving the performance of cotton fiber and improving the style of cotton products, but a layer of chemical substances is cross-linked on the surface of cotton fiber, which reduces the wearing comfort of cotton fiber, a green natural fiber. Therefore, This modification method is more and more difficult to meet people's demand for high performance of textile materials. The other is to use the "bridging" effect of chemical cross-linking agents or coupling agents to attach functional materials, biomaterials or nanomaterials to cotton fibers in the form of cross-linking and grafting, so that cotton fibers with new features. Due to the use of a cross-linking agent as a "bridge", this method can make other materials and cotton fibers produce a firm combination, which has positive significance for endowing cotton fibers with new functions and expanding their application fields. But this method also has a big problem, because a chemical crosslinking agent is used in the reaction process, a layer of chemical substances is inevitably attached to the surface of the cotton fiber, which destroys the green natural cellulose fiber of the cotton fiber. The original appearance of natural cotton fiber causes "chemical fiberization" on the surface of natural cotton fiber, and has some adverse effects on the human body. It is difficult to meet the requirements of green production and green ecological textiles advocated today. With the continuous strengthening of human awareness of environmental protection, a wave of "returning to nature" and "green consumption" has been set off in countries all over the world. This modification method has been challenged more and more seriously. Therefore, while maintaining the advantages of natural cotton fibers, how to find suitable modification methods to improve the performance of cotton fibers and endow them with new functions is an urgent problem to be solved.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing modified cotton fibers that not only maintains the original excellent natural characteristics of cotton fibers, but also imparts new functions and properties to cotton fibers.

The present invention adopts following technical scheme to realize the object of the present invention: a kind of preparation method of modified cotton fiber is provided, and it adopts following specific steps:

a. Scouring and bleaching the twisted cotton yarn;

b. placing the treated cotton yarn in a solution with a periodate concentration of 0.1 to 3 g/L for selective oxidation reaction, the temperature of the reaction solution is 30 to 60° C., and the treatment time is 1 to 2 hours;

c. after removing the oxidizing agent on the cotton fiber, then through washing, dehydration, and drying, obtain the oxidized cotton fiber whose strength and elongation decrease rate is lower than 25%;

d. Grafting and cross-linking the oxidized cotton fibers with substances having -NH ₂ and -OH active groups in the molecular chains to prepare modified cotton fibers.

Described periodate is sodium periodate or potassium periodate. The breaking strength decrease rate of the oxidized cotton fiber is less than 25%.

The method for removing the oxidizing agent on the cotton fiber is: soak the cotton fiber in a glycerol solution with a concentration of 0.1-0.5 mol/L for 30-60 minutes.

The substance with -NH ₂ , -OH active groups may be collagen, chitosan, silk fibroin or sericin, etc.

Compared with the existing method of cotton fiber modification, the present invention has the advantages of:

By adopting the preparation method provided by the present invention, on the one hand, by controlling the selective oxidation process conditions, the prepared oxidized cotton fiber can maintain a certain wearing strength and elongation, and the oxidized cotton fiber, as a kind of cellulose derivative, still has good biological properties. Characterized by compatibility, biodegradability, environmental friendliness and non-toxicity, it maintains the excellent properties of natural cotton fibers. On the other hand, periodate undergoes a selective oxidation reaction with cotton fibers to generate active aldehyde groups in cotton cellulose macromolecules, which can react with functional materials and nanomaterials with active groups such as -NH ₂ and -OH Other substances undergo grafting and cross-linking reactions, which can modify cotton fibers, prepare new functional and multifunctional composite cotton fibers, improve the wearability and added value of cotton fibers, and effectively solve the problem in the field of textile fiber raw materials. Functionalization of cotton fibers. The method adopted in the invention realizes clean and pollution-free production, ensures the further development of eco-friendly green cotton fiber products, and greatly expands the application field of cotton fibers.

Description of drawings

Fig. 1 is a comparison chart of infrared spectrum absorption curves before and after selective oxidation of cotton fiber in this embodiment.

In the figure: curve a represents the infrared spectrum absorption curve of cotton fiber, and curve b represents the infrared spectrum absorption curve of oxidized cotton fiber.

Detailed ways

The present invention will be further elaborated below in conjunction with embodiment.

Embodiment one:

The twisted 50.5 Tex cotton yarn is scoured with caustic soda to remove impurities, and then bleached with hydrogen peroxide. Then put the cotton yarn into the sodium periodate solution with a concentration of 1g/L, keep the temperature of the reaction solution at 55°C, stir and treat it for 1 hour under the condition of bath ratio 1:200, take it out, and use 0.1mol/L glycerine Soak in alcohol solution for 30 minutes; Soak in water at room temperature for 24 hours, remove the oxidant on the cotton fiber, dehydrate after washing with warm water for several times, you can get the oxidized cotton fiber that keeps a certain strength and elongation (breaking strength decreases by 14%, elongation rate decreased by 7%); before the above-mentioned selective oxidation reaction, the molecular structure of cotton fiber is

, on the C ₂ and C ₃ positions are secondary hydroxyl groups, in the selective oxidation reaction, the IO ₄ ^-ion in the periodate will convert the cotton cellulose macromolecular chain glucopyranose to the C ₂ and _C 3 positions The secondary hydroxyl group is selectively oxidized to form an aldehyde group, and its molecular structure is

Under the process conditions of this embodiment, the secondary hydroxyl groups on the _C2 and _C3 positions in the cotton fiber macromolecular chain are only slightly oxidized, and its internal structure does not change much. Therefore, the tensile elongation of the cotton fiber after oxidation does not decrease much. .

Then put the oxidized cotton fibers in a collagen solution with a concentration of 1%, adjust the pH value of the reaction solution to 4.0-5.0, keep the temperature of the reaction solution at 40°C, stir for 1 hour under the condition of a bath ratio of 1:100, and then take it out , baked in an oven at 60°C for 4 hours; then the cotton yarn is fully washed with clean water, dehydrated, and dried at 60°C to obtain a new type of functional cotton fiber coated with collagen. Collagen is on the cotton fiber The binding amount is about 1.41%.

Fig. 1 is the comparison chart of infrared spectra before and after the selective oxidation reaction of cotton fiber in this embodiment. Referring to accompanying drawing 1, what curve a in the figure represented is the infrared spectrogram of cotton fiber, and what curve b represented was the infrared spectrogram of oxidized cotton fiber. It can be seen from the infrared spectrogram that, compared with curve a, curve b has an obvious absorption peak at 1709.2 cm ^-1 , which is the characteristic absorption peak of aldehyde group. It can be seen that the cotton fiber macromolecular chain The secondary hydroxyl groups at the _C2 and _C3 positions in the anhydroglucopyranose link are selectively oxidized into aldehyde groups, which can be directly combined with other substances such as functional materials and nanomaterials without adding any cross-linking agent or other chemical substances. The functional material or nanomaterial that reacts with the oxidized cotton fiber can be other green polymer materials such as collagen, chitosan, silk fibroin or sericin, through the aldehyde group in the macromolecule of the oxidized cotton fiber and the high Active groups in molecular substances react to make functional materials or nanometer materials firmly coated on cotton fibers, and new functional cotton fibers and multifunctional composite cotton fibers are prepared.

Claims (3)

1. a preparation method of modified cotton fiber is characterized in that: it adopts following concrete steps: a. Scouring and bleaching the twisted cotton yarn; b. placing the treated cotton yarn in a solution with a periodate concentration of 0.1 to 3 g/L for selective oxidation reaction, the temperature of the reaction solution is 30 to 60° C., and the treatment time is 1 to 2 hours; c. After removing the oxidizing agent on the cotton fiber, it is washed, dehydrated and dried to obtain oxidized cotton fiber; d. Grafting and cross-linking the oxidized cotton fibers with substances having -NH ₂ and -OH active groups in the molecular chains to prepare modified cotton fibers. 2. A method for preparing modified cotton fibers according to claim 1, characterized in that the periodate is sodium periodate or potassium periodate. 3. A method for preparing modified cotton fibers according to claim 1, characterized in that: said oxidized cotton fibers have a decrease rate of breaking strength lower than 25%.