Controllable color-changing electric heating yarn and preparation method thereof

Abstract

The invention relates to the technical field of functional fibers, in particular to a controllable color-changing electric heating yarn and a preparation method thereof.The controllable color-changing electric heating yarn is of a four-layer composite structure sequentially comprising a core layer, a conductive layer, a wrapping layer and a color-changing layer from inside to outside, and the controllable color-changing electric heating yarn of the four-layer composite structure is prepared through wrapping, short fiber wrapping and coating technologies. The fabric has good conductivity, thermal performance and color changing performance, can be produced at a high speed by using an existing textile machine, and is low in cost.

Description

Technical Field

[0001] The invention relates to the technical field of functional fibers, and in particular to a controllable color-changing electrothermal yarn and a preparation method thereof. Background Art

[0002] With the popularization of the concept of "smart wearables", people combine textiles with various new smart materials to produce more diversified and intelligent products. For users, wearable functional products that are lighter, fit the human body and are more comfortable are urgently needed. One-dimensional smart fibers and functional yarns have emerged to meet these requirements.

[0003] As a product with high added value and high benefits, flexible color-changing fibers have good development prospects in the fields of military, entertainment, anti-counterfeiting, etc. The color-changing mechanism can be mainly divided into electrochromic, photochromic, mechanochromic, thermochromic, etc. Among them, photochromic and electrochromic materials change color when the crystal structure changes. Although they have good stability, they have low sensitivity; the color of mechanochromic materials changes with the change of molecular structure, and their service life is short; the structure of thermochromic materials is relatively simple, but their color change depends on thermal decomposition, and the color change effect is affected by environmental factors. Overall, no matter which kind of smart color-changing material, it will be restricted in actual production and use.

[0004] In addition, there are usually two relatively simple ways to prepare color-changing fibers: one is to directly mix the color-changing material with the polymer and then spin it; the other is to coat the color-changing material on the fiber by coating. However, the former is difficult to mass produce and the parameter control is relatively complex, and the latter coating quality directly affects the color development effect. Summary of the invention

[0005] In order to improve the technical defects in the application of the above-mentioned color-changing materials and the preparation method of functional yarns, the present invention provides a controllable color-changing electrothermal yarn and a preparation method thereof. The controllable color-changing electrothermal yarn with a four-layer composite structure is prepared by wrapping, short fiber wrapping and coating processes. It has good electrical conductivity, thermal properties and color-changing properties, and can be produced at a relatively fast speed using existing textile machines at a low cost.

[0006] The present invention provides a controllable color-changing electrothermal yarn, which has four composite structures, from the inside to the outside, namely, a core layer, a conductive layer, a coating layer, and a color-changing layer;

[0007] The core layer is a polyurethane yarn, the polyurethane yarn has a fineness of 560D and is composed of 24 monofilaments;

[0008] The conductive layer is a conductive yarn obtained by modifying cotton yarn with a composite material obtained by doping multi-walled carbon nanotubes with graphene water-based conductive slurry, wherein the diameter of the graphene sheet in the graphene water-based conductive slurry is 10 to 50 μm, the length of the multi-walled carbon nanotubes is 3 to 12 μm, and the specification of the cotton yarn is 40s / 2;

[0009] The material used for the coating layer is cotton fiber, and the roving cotton strip composed of the cotton fiber has a specification of 300tex, which is coated on the conductor layer after the spinning process to form a coating layer;

[0010] The material used for the color-changing layer is a thermosensitive color-changing microcapsule, and the diameter of the thermosensitive color-changing microcapsule is 2 to 5 μm.

[0011] The present invention also discloses a preparation process of a controllable color-changing electrothermal yarn, comprising the following steps:

[0012] (1) Preparation of graphene / multi-walled carbon nanotube composite conductive ink:

[0013] Slowly add 1.5-2.5 parts of multi-walled carbon nanotubes to the graphene aqueous conductive slurry, and add 30-50 parts of quantitative deionized water to make the overall carbon content in the composite conductive ink 5%;

[0014] After adding 0.5 to 1 part of a binder, stirring for 30 to 60 minutes and ultrasonicating for 45 to 60 minutes, a composite conductive ink is obtained;

[0015] The mass ratio of graphene to multi-walled carbon nanotubes is 2 to 3:1;

[0016] The binder is one or more of waterborne polyurethane, waterborne polyurethane resin, waterborne epoxy resin, and waterborne acrylic resin;

[0017] (2) Preparation of conductive cotton yarn:

[0018] The cotton yarn is immersed in the graphene / multi-walled carbon nanotube composite conductive ink, ultrasonically immersed for 30 to 45 minutes, and then heated at 40 to 50° C. for 2 to 3 minutes, and the operation is repeated 3 to 10 times to obtain the conductive cotton yarn;

[0019] (3) Preparation of spirally wrapped composite conductive yarn:

[0020] The polyurethane yarn is pre-stretched by 20-60% and then clamped at both ends of the wrapping machine in a straight state. One end of the conductive cotton yarn is fixed, and the two yarns are 60-90 degrees. The yarns are pulled and uniformly wrapped on the surface of the polyurethane yarn at a speed of 200-400 r / min.

[0021] (4) Preparation of cotton fiber coated yarn:

[0022] The spirally wrapped composite conductive yarn is used as the core, and the cotton fiber is evenly coated on the surface of the core yarn through a spinning process;

[0023] (5) Preparation of controllable color-changing electrothermal yarn:

[0024] The thermochromic ink is obtained by dissolving the thermochromic microcapsules in deionized water, adding a binder and a thickener, stirring for 15 to 30 minutes, and then performing ultrasonic defoaming treatment.

[0025] The cotton fiber coated yarn is then immersed for 3 to 8 minutes and then taken out for drying. The oven temperature is controlled at 40 to 50° C. and the hot drying time is 10 to 30 minutes.

[0026] Furthermore, in step (2), the cotton yarn needs to be treated with 10 g / L sodium hydroxide at 95-98° C., and then rinsed with deionized water and dried at room temperature.

[0027] Furthermore, in step (4), the spirally wrapped composite conductive yarn passes through a yarn guide device installed on the front roller cradle of the spinning frame without being stretched, is fed by the front roller, overlaps with the stretched cotton slivers, and is twisted together after passing through the front roller.

[0028] Furthermore, in step (4), the drafting multiple during spinning is 8 to 60, the twist is 60 to 70 twists / 10 cm, the twist shrinkage is 2 to 3%, and the yarn number is 30 to 50 tex.

[0029] Furthermore, in step (5), the weight portions of the components of the thermochromic ink are: 10 parts of thermochromic microcapsules, 10 to 20 parts of a binder, 5 parts of a thickener, and 65 to 75 parts of deionized water.

[0030] Furthermore, in step (5), the temperature-sensitive color-changing microcapsules have a color-changing temperature of one or more of 33, 38, and 45° C., and the color-changing and fading times are 6 to 10 seconds and 4 to 7 seconds, respectively.

[0031] The above structure enables this solution to have the following beneficial effects:

[0032] 1. Multi-layer composite structure: The core layer polyurethane yarn provides elasticity; the conductive layer is made of a mixture of two carbon materials, which has better conductivity and thermal effects; the coating layer is made of cotton fiber, which is low in cost and can well cover the black conductive layer, improving the technical defect of using thick coatings to cover dark materials, which affects the comfort of use; the color-changing layer is added with a binder, which can effectively improve the fastness of the coating. Thanks to the existence of the coating layer, the color-changing effect can be achieved with a thinner coating;

[0033] 2. Diverse functions: The excellent electrothermal properties of carbon materials are combined with the temperature-sensitive color-changing properties of color-changing materials to prepare electrothermal-induced color-changing materials with the advantages of both. They can be used in the fields of conductive sensing, electric heating and color-changing response, thus greatly broadening the application range of color-changing fibers.

[0034] 3. The color-changing effect is controllable: the color-changing effect, including time and color, can be controlled by the size of the applied voltage. In addition, the preparation of wide-color color-changing electrothermal yarn can be achieved by changing the temperature-sensitive color-changing material used in the color-changing layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0036] Figure 1 Schematic diagram of the process for preparing controllable color-changing electrothermal yarn in an embodiment of the present invention.

[0037] Figure 2 Schematic diagram of the structure of the controllable color-changing electrothermal yarn formed in an embodiment of the present invention.

[0038] Figure 3 This is a scanning electron microscope image of the color-changing layer of the controllable color-changing electrothermal yarn formed in Example 1 of the present invention.

[0039] Figure 4 This is an image of the relationship between voltage and temperature of the controllable color-changing electrothermal yarn formed in Example 1 of the present invention.

[0040] Figure 5 This is a comparison diagram of the controllable color-changing electrothermal yarn formed in Example 1 of the present invention before and after color change. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0042] Embodiment 1:

[0043] (1) Weighing 0.5 g of multi-walled carbon nanotubes, slowly adding them into 20 g of graphene aqueous conductive slurry, then adding 10 ml of deionized water, and then dropping 1 g of aqueous polyurethane, stirring for 40 min, and then ultrasonicating for 60 min to obtain a black composite conductive ink;

[0044] (2) placing the cotton yarn treated with NaOH (40s / 2) into the composite conductive ink, ultrasonically immersing for 30 min, taking it out and placing it in an oven for drying at 45°C for 2 min, repeating the operation 6 times to obtain the conductive cotton yarn;

[0045] (3) pre-stretching the 560D polyurethane yarn (11) by 40%, fixing both ends of the yarn on the clamps (13) at both ends of the wrapping machine, fixing one end of the conductive cotton yarn (12), and wrapping the two yarns at a constant speed of 280 r / min at a 90° angle to obtain a composite conductive yarn with a spiral wrapping structure;

[0046] (4) Using 300tex cotton sliver (15), the spinning frame process parameters are: yarn number 30tex, drafting multiple 10.3, twist 60 twists / 10cm. The spirally wrapped composite conductive yarn passes through the yarn guide device (14) installed on the front roller cradle of the spinning frame without being drafted, and is fed by the front roller (16) to overlap with the drafted cotton sliver. After twisting, the cotton fibers are coated on the spirally wrapped composite conductive yarn to obtain coated yarn;

[0047] (5) 2 g of thermochromic microcapsules that change color at 38°C were dissolved in 15 g of deionized water, and 2 g of aqueous polyurethane and 1 g of thickener were added. The mixture was stirred for 20 min and ultrasonicated for 10 min to obtain a thermochromic ink. The cotton fiber coated yarn was immersed in the ink for 5 min and then heated at 40°C for 15 min to obtain a controllable color-changing electrothermal yarn.

[0048] The controllable color-changing electrothermal yarn has a four-layer structure, which comprises a core layer (21), a conductive layer (22), a coating layer (23), and a color-changing layer (24).

[0049] Embodiment 2:

[0050] The content of this embodiment is basically the same as that of embodiment 1, and the same parts are not repeated here. The difference from embodiment 1 is as follows:

[0051] When preparing the composite conductive ink, 0.4 g of multi-walled carbon nanotubes was weighed and slowly added to 24 g of graphene aqueous conductive slurry, and then 12 ml of deionized water was added and 1 g of aqueous polyurethane was added dropwise for stirring and ultrasonic treatment;

[0052] Conductive cotton yarn was prepared by 10 cycles of dipping-drying treatment;

[0053] When preparing the spirally wrapped composite conductive yarn, the polyurethane yarn is pre-stretched by 50%;

[0054] Since the cotton yarn has been impregnated and dried too many times with the composite conductive ink, the yarn feels hard, which affects the wrapping and subsequent cotton fiber covering effect, so some parts of the yarn are uneven; however, due to the large number of impregnation times, the conductivity and electric heating effects of the yarn are not much different from those in Example 1.

[0055] Embodiment 3:

[0056] The content of this embodiment is basically the same as that of embodiment 1, and the same parts are not repeated here. The difference from embodiment 1 is as follows:

[0057] The conductive cotton yarn was prepared by three cycles of dipping-drying treatment;

[0058] When preparing the color-changing ink, 2 g of the thermosensitive color-changing microcapsules that change color at 33°C were dissolved in 13 g of deionized water, and 4 g of waterborne polyurethane and 1 g of thickener were added for stirring and ultrasonication;

[0059] Since the composite conductive ink is immersed and dried too few times, the conductive properties are much different from those in Example 1, which in turn affects the thermal properties. Under the same voltage, the temperature rise is lower, thus affecting the color change effect.

[0060] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A controllable color-changing electric heating yarn, It is characterized in that It includes a four-layer structure, which includes a core layer, a conductive layer, a coating layer, and a color-changing layer from the inside to the outside.

2. The color-controllable electrothermal yarn according to claim 1, It is characterized in that The core layer material is high-elastic polyurethane yarn; The graphene aqueous conductive slurry is doped with multi-walled carbon nanotubes to obtain a composite conductive ink, and the conductive layer is a conductive cotton yarn obtained by impregnating the cotton yarn with the composite conductive ink; The material used for the coating layer is cotton fiber; The color-changing layer is a temperature-sensitive color-changing layer, and the material used is a temperature-sensitive color-changing microcapsule.

3. The color-controllable electrothermal yarn according to claim 2, It is characterized in that The polyurethane yarn has a fineness of 560D and is composed of 24 monofilaments; The diameter of the graphene sheet in the graphene aqueous conductive slurry is 10 to 50 μm; the length of the multi-walled carbon nanotube is 3 to 12 μm; the specification of the cotton yarn in the conductive layer is 40s / 2; The coating layer is a 300tex roving cotton strip that has been subjected to a spun yarn process so that the cotton fibers are coated on the composite conductive yarn; The diameter of the temperature-sensitive color-changing microcapsules in the color-changing layer is 2 to 5 μm.

4. A method for preparing the controllable color-changing electrothermal yarn according to claims 1 to 3, It is characterized in that The following steps are involved: (1) Preparation of graphene / multi-walled carbon nanotube composite conductive ink: Slowly add 1.5-2.5 parts of multi-walled carbon nanotubes to the graphene aqueous conductive slurry, and add 30-50 parts of quantitative deionized water to make the overall carbon content in the composite conductive ink 5%; After adding 0.5 to 1 part of a binder, stirring is performed for 30 to 60 minutes and ultrasonication is performed for 45 to 60 minutes to obtain a composite conductive ink, wherein the mass ratio of graphene to multi-walled carbon nanotubes is 2 to 3:1; The binder is one or more of waterborne polyurethane, waterborne polyurethane resin, waterborne epoxy resin, and waterborne acrylic resin; (2) Preparation of conductive cotton yarn: The cotton yarn is immersed in the graphene / multi-walled carbon nanotube composite conductive ink, ultrasonically immersed for 30 to 45 minutes, and then heated at 40 to 50° C. for 2 to 3 minutes, and the operation is repeated 3 to 10 times to obtain the conductive cotton yarn; (3) Preparation of spirally wrapped composite conductive yarn: The polyurethane yarn is pre-stretched by 20-60% and then clamped at both ends of the wrapping machine in a straight state. One end of the conductive cotton yarn is fixed. The polyurethane yarn and the conductive cotton yarn are at an angle of 60-90 degrees. The conductive cotton yarn is pulled and uniformly wrapped on the surface of the polyurethane yarn at a speed of 200-400 r / min to form a conductive layer. At this time, the polyurethane yarn and the conductor cotton yarn form a spirally wrapped composite conductive yarn; (4) Preparation of cotton fiber coated yarn: With the spirally wrapped composite conductive yarn as the core, the 300tex coarse yarn sliver is subjected to a spinning process, and the cotton fibers in the spun yarn are evenly coated on the surface of the core yarn to obtain a coating layer; (5) Preparation of controllable color-changing electrothermal yarn: The thermochromic ink is obtained by dissolving the thermochromic microcapsules in deionized water, adding a binder and a thickener, stirring for 15 to 30 minutes and performing ultrasonic defoaming treatment. Then the cotton fiber covered yarn is immersed in it, taken out and dried after 3 to 8 minutes, the oven temperature is controlled at 40 to 50° C., the hot drying time is 10 to 30 minutes, and a color-changing layer is formed.

5. A method for preparing a controllable color-changing electrothermal yarn according to claim 4, It is characterized in that In step (2), the cotton yarn needs to be treated with sodium hydroxide at a temperature of 95-98° C. and a concentration of 10 g / L to remove impurities, and then rinsed with deionized water and dried at room temperature.

6. A method for preparing a controllable color-changing electrothermal yarn according to claim 4, It is characterized in that In step (4), in the spinning process, a yarn guiding device needs to be installed on the front roller cradle of the spinning machine. The spirally wrapped composite conductive yarn passes through the yarn guiding device without being stretched, is fed by the front roller, overlaps with the stretched cotton slivers, and is twisted together after passing through the front roller.

7. A method for preparing a controllable color-changing electrothermal yarn according to claim 6, It is characterized in that In step (4), in the spinning process, the drafting multiple is 8 to 60, the twist is 60 to 70 twists / 10 cm, the twist shrinkage is 2 to 3%, and the yarn number is 30 to 50 tex.

8. A method for preparing a controllable color-changing electrothermal yarn according to claim 4, It is characterized in that In step (5), the weight parts of the components of the thermochromic ink are: 10 parts of thermochromic microcapsules, 10-20 parts of binder, 5 parts of thickener, and 65-75 parts of deionized water.

9. The method for preparing a color-controllable electrothermal yarn according to claim 4, It is characterized in that In step (5), the temperature-sensitive color-changing microcapsules have a color-changing temperature of one or more of 33, 38, and 45° C., and the color-changing and fading times are 6 to 10 seconds and 4 to 7 seconds, respectively.

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