High-dispersion superfine fiber and preparation method thereof

Abstract

The invention discloses a high-dispersion superfine fiber and a preparation method thereof, and belongs to the technical field of sea-island fiber material processing.The preparation method of the high-dispersion superfine fiber comprises the following steps that figured sea-island short fibers are subjected to alkali decrement, and superfine fibers are obtained; and soaking the superfine fibers in a compound additive mixed solution for compounding treatment, taking out the superfine fibers, and drying the superfine fibers to prepare the high-dispersion superfine fibers. The figured sea-island short fibers are subjected to decrement and post-treatment, and the high-dispersion superfine fibers with good dispersity, softness and bulkiness are obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of island fiber material processing, and particularly relates to a high-dispersion superfine fiber and a preparation method thereof. BACKGROUND

[0002] With the development of the papermaking industry and the composite material industry, high-performance fibers have also become one of the important raw materials in the paper-based composite material industry. The special performance of high-performance fibers provides a prerequisite for manufacturing paper-based materials with special performance. Most high-performance fibers do not have hydrophilic groups, and thus have poor dispersion performance in water. The dispersion performance of fibers is one of the important factors affecting the forming and strength of paper-based composites, and therefore, solving the dispersion performance of fibers becomes the primary problem of the application of high-performance fibers in the papermaking industry.

[0003] In addition, the types of filling fiber materials are various and are constantly enriched with the development of the chemical fiber industry. At present, there are mainly three kinds of filling fibers for warmth on the market in China. One is natural warm filling fiber, and the used fibers can be divided into plant fibers and animal fibers. The plant fibers are mainly cotton fibers, and the animal fibers are mainly wool fibers, down fibers, silk fibers and the like. The second is batting made of pure chemical fiber materials and batting made of natural fibers and chemical fibers. Generally, synthetic fibers can be used as warm materials, such as polyester, acrylic, polypropylene and viscose fibers. These fibers can be made into hot-melt batting, glue cotton batting and needle-punched batting through different processing technologies. At the same time, mixing a certain amount of chemical fibers into natural fibers can make up for the shortcomings of natural fiber batting. The third is space cotton, antarctic cotton and solar down made of various materials through special composite processing. With the development of the chemical fiber industry, various special warm fibers have appeared, such as hollow three-dimensional high-curl polyester, far-infrared polypropylene and the like. Compared with natural fibers such as wool or goose down, polyester fiber quilts have poor warmth. This is because polyester fibers have high thermal conductivity and are easy to conduct heat, and thus cannot keep warm well. Therefore, how to improve the loftiness and warmth of polyester superfine fibers is still a problem to be solved. SUMMARY

[0004] The application aims to provide a high-dispersion superfine fiber and a preparation method thereof, and solve the problems that most high-performance fibers do not have hydrophilic groups and have poor dispersion performance in water and that the fibers have low loftiness and cannot be used as fillers.

[0005] To achieve the above application purposes, the application adopts the following technical solutions.

[0006] In a first aspect, the application provides a preparation method of a high-dispersion superfine fiber, which comprises the following steps: performing alkali reduction on island-type island short fibers to obtain superfine fibers, immersing the superfine fibers in a mixed solution of a complexing agent for complexing treatment, taking out the superfine fibers after the treatment, and drying the superfine fibers to obtain the high-dispersion superfine fibers.

[0007] Furthermore, the island-type short fiber is a COPET / PET or COPET / PA6 type island-type short fiber.

[0008] This invention obtains microfibers with good dispersibility, softness, and bulkiness by subjecting island-shaped short fibers to alkali reduction and post-treatment. First, island-shaped short fibers prepared from alkali-soluble polyester (COPET) / polyethylene terephthalate (PET) or polycaprolactam (PA6) are subjected to alkali reduction treatment. Then, they are treated with a mixture of softeners and bulking agents to obtain microfibers with good dispersibility, bulkiness, and softness.

[0009] Furthermore, the fixed-island short fiber contains 8-37 island components, the proportion of sea components in the fixed-island short fiber is 30%, and the length of the fixed-island short fiber is 2-25mm.

[0010] In this invention, the weight loss rate of marine components is controlled to be M±1% during the preparation of ultrafine fibers, where M is the actual proportion of marine components.

[0011] This invention selects island-type short fibers of the COPET / PET or COPET / PA6 type as raw materials. The sea component (COPET) accounts for 30%, and the island component (PET / PA6) contains 8-37 monofilaments. The sea component is selectively dissolved through alkali reduction, while the island component is retained to form ultrafine fibers. By utilizing the phase separation characteristics of the island fibers, precise control of the fiber diameter is achieved through chemical etching.

[0012] Furthermore, the alkali reduction includes the following steps: adding the island-shaped short fibers to a sodium hydroxide solution, and then reducing the weight to obtain ultrafine fibers.

[0013] Furthermore, the sodium hydroxide solution has a mass concentration of 1-5 wt.%.

[0014] Furthermore, the ratio of the mixture of microfiber and compound additives is 1g:10mL; the temperature of the water bath reaction is 90-100℃.

[0015] This invention involves reducing the weight of island-shaped short fibers in a sodium hydroxide solution. By precisely controlling the concentration of the sodium hydroxide solution and the water bath reaction temperature, the island component COPET undergoes a hydrolysis reaction under alkaline conditions and is dissolved and removed, achieving the separation and refinement of the island component and obtaining a preliminary ultrafine fiber structure, laying the foundation for subsequent dispersibility improvement.

[0016] Furthermore, the concentration of the compound additives in the compound additive mixture is 0.5-5 wt.%.

[0017] Furthermore, the compound additive consists of a leavening agent and a softener; the mass ratio of the leavening agent to the softener is 1:(0.6-2.5).

[0018] Furthermore, the compounding process takes 5 minutes.

[0019] Excessive compounding time will not cause any problems, but it will affect the overall processing effect. Insufficient compounding time will result in uneven compounding, which is not conducive to subsequent use.

[0020] In this invention, the ultrafine fibers obtained after alkali reduction are immersed in a mixture of compound additives. During this process, the bulking agent acts on the fiber surface, changes the interaction force between fibers, increases the gaps between fibers, and makes the fiber structure more fluffy. The softener adheres to the fiber surface, reduces the coefficient of friction of the fiber surface, and enhances the softness of the fiber. The two work together to effectively improve the dispersibility of the ultrafine fibers.

[0021] Secondly, the present invention provides a highly dispersed ultrafine fiber, which is prepared by the above-described preparation method.

[0022] Thirdly, the present invention provides an application of the above-mentioned highly dispersed ultrafine fibers in the preparation of paper-based composite materials and in the preparation of filler fiber materials.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] This invention removes marine components through alkali reduction treatment, causing the island components to form ultrafine fibers with a significantly reduced fiber diameter and a significantly increased specific surface area. Further treatment with compounding agents alters the physicochemical properties of the fiber surface, reducing fiber agglomeration and enabling more uniform dispersion of the ultrafine fibers in the dispersion medium, effectively solving the problem of poor dispersion of existing ultrafine fibers. The compounding process in this invention utilizes a softener to make the fibers softer and smoother, effectively eliminating static electricity and improving comfort during use, while also facilitating subsequent processing. A bulking agent increases the gaps between the ultrafine fibers, making the fiber structure more porous. This loose structure not only increases the fiber volume, improving its thermal insulation and breathability, but also allows the fibers to better integrate with other components in composite materials and other applications, enhancing the overall performance of the composite materials. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] This invention provides a method for preparing highly dispersed ultrafine fibers, comprising the following steps:

[0031] S1. Preparation of microfiber: Using short island fibers of the COPET / PET or COPET / PA6 type with 8-37 islands, a length of 2-25mm and an island ratio of 30wt.% as raw materials, microfibers are prepared by treating them with a sodium hydroxide solution of 1-5wt.% at 90-100℃.

[0032] S2. Preparation of compound additive mixture: The compound additive is composed of a leavening agent (cationic surfactant) and a softener (amino-modified organosilicon softener) in a certain proportion; the mass ratio of the leavening agent to the softener is 1: (0.6-2.5).

[0033] The compound additive mixture is made by mixing compound additives and water, with water accounting for 95-99.5% and additives accounting for 0.5-5%, and the proportions are adjusted by mass.

[0034] S3. The microfiber prepared in step S1 is placed into a container containing a mixture of compound auxiliaries, soaked for 5 minutes, and dried in an oven at 80°C until constant weight.

[0035] In the following embodiments of the present invention, the leavening agent is a cationic surfactant (Guangzhou Deyuan Fine Chemical Co., Ltd., DR8818), and the softener is an amino-modified silicone softener (Guangzhou Deyuan Fine Chemical Co., Ltd., 6650), both of which were purchased commercially. The COPET / PET island fiber in the embodiments of the present invention was provided by Linyi Dazheng Special Fiber New Material Co., Ltd. All the above-mentioned purchased raw materials were used directly without further purification.

[0036] In this embodiment of the invention, all solutions were prepared using deionized water.

[0037] Examples 1-4 (Specialty Paper Dispersion Examples)

[0038] S1. Cut COPET / PET (containing 37 island components and 30% sea component) filaments into short fibers of 3-6 mm, then place the cut short fibers in a sodium hydroxide solution (3 wt.%) and stir and heat in a 90°C water bath for 30 min to remove the sea component and prepare ultrafine fibers, wherein the sea component removal ratio is 29.5%.

[0039] S2. The fluffing agent and softener are prepared into compound auxiliaries according to the proportions in Table 1. In each example, the compound auxiliaries and water are prepared into compound auxiliary mixtures at mass ratios of 2:98, 0.5:99.5, and 5:95, respectively. The ultrafine fibers from S1 are added to the compound auxiliary mixture at a ratio of 1g:10mL, soaked for 5 minutes, and then removed. The impregnation liquid in the fibers is drained, maintaining a liquid retention rate of 150%. The fibers are then placed in an oven at 80℃ and dried to constant weight to obtain highly dispersed ultrafine fibers.

[0040] Table 1

[0041]

[0042] Comparative Example 1

[0043] Same as Example 4, except that the leavening agent used is DR9275;

[0044] The highly dispersed ultrafine fibers prepared in Examples 1-4 and Comparative Example 1 were placed in water and stirred mechanically to obtain a fiber suspension. The stirring time was 10 min, and then the suspension was allowed to stand for 0.5 h. The degree of dispersion was calculated, and the results are shown in Table 2. The calculation formula is as follows:

[0045] ;

[0046] Where f: dispersibility; V0: volume of fiber suspension at the start of sedimentation, mL; V1: volume of supernatant layer in container after 0.5 h, mL.

[0047] Table 2

[0048]

[0049] The reason why the dispersion was poor in Comparative Example 1 due to the use of different bulking agents is that the bulking agent DR9275 did not bond well with the fiber surface, resulting in some of the fiber surface not being fully covered, and strong charge adsorption between fibers.

[0050] Examples 5-8 (Filler Examples)

[0051] S1. Cut COPET / PET (containing 37 island components and 30% sea component) filaments into short fibers of 15-18 mm, then place the cut short fibers in a sodium hydroxide solution (3 wt.%) and stir and heat in a 90°C water bath for 30 min to remove the sea component and prepare ultrafine fibers, wherein the sea component removal ratio is 29.5%.

[0052] S2. Prepare compound auxiliaries by mixing the fluffing agent and softener according to the ratio in Table 1. In each example, the compound auxiliaries and water are prepared into compound auxiliary mixtures at mass ratios of 2:98, 0.5:99.5, and 5:95, respectively. Add the ultrafine fibers from S1 to the compound auxiliary mixture at a ratio of 1g:10mL, soak for 5 minutes, remove, drain the impregnation liquid from the fibers, maintain a liquid retention rate of 200%, and dry in an 80℃ oven to constant weight to obtain highly dispersed ultrafine fibers.

[0053] Comparative Example 2

[0054] Same as Example 8, except that the leavening agent used is DR9275;

[0055] The bulkiness, heat retention rate, and air permeability of the highly dispersed microfibers prepared in Examples 5-8 and Comparative Example 2 were investigated. The bulkiness was tested according to GB / T14272, the heat retention rate was tested according to GB / T35762, and the air permeability was tested according to GB / T5453. The test results are shown in Tables 3-5.

[0056] Table 3

[0057]

[0058] Table 4

[0059]

[0060] Table 5

[0061]

[0062] The reason why different fluffing agents were used in Comparative Example 2 resulted in poor performance in various indicators is that the fiber fluffiness could not meet the requirements for heat preservation and breathability, thus the porosity between fibers could not be kept uniform, and some agglomeration occurred, resulting in a reduction in the amount of static air and poor overall heat preservation.

[0063] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing highly dispersed ultrafine fibers, characterized in that, Includes the following steps: The island-type short fibers are subjected to alkali reduction treatment to obtain ultrafine fibers. The ultrafine fibers are then placed in a compounding agent mixture for compounding treatment, and after being taken out and dried, the highly dispersed ultrafine fibers are obtained.

2. The preparation method according to claim 1, characterized in that, The island-type short fibers are selected from COPET / PET or COPET / PA6 type island-type short fibers.

3. The preparation method according to claim 2, characterized in that, The fixed-island short fiber contains 8-37 island components, the proportion of marine components in the fixed-island short fiber is 30 wt.%, and the length of the fixed-island short fiber is 2-25 mm.

4. The preparation method according to claim 1, characterized in that, The alkali reduction treatment includes the following steps: adding the island-shaped short fibers to a sodium hydroxide solution and reducing the weight to obtain ultrafine fibers.

5. The preparation method according to claim 1, characterized in that, The ratio of the mixture of microfiber and compound additives is 1g:10mL.

6. The preparation method according to claim 1, characterized in that, The concentration of the compound additives in the compound additive mixture is 0.5-5 wt.%; the compound additives consist of a leavening agent and a softener; the mass ratio of the leavening agent to the softener is 1:(0.6-2.5).

7. The preparation method according to claim 1, characterized in that, The compounding process takes 5 minutes.

8. A highly dispersed ultrafine fiber, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

9. The application of the highly dispersed ultrafine fiber as described in claim 8 in the preparation of paper-based composite materials and the preparation of filler fiber materials.

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