Foamed yarn and preparation method thereof

Abstract

The invention relates to the technical field of yarn post-treatment, in particular to foamed yarn and a preparation method thereof. The preparation method comprises the following steps: sizing yarns in a mixed solution of a curing agent and slurry, and then sequentially curing and foaming to obtain foamed yarns, the slurry comprises foaming resin and thermal expansion microspheres. According to the preparation method, slurry is cured and foamed to form a foaming coating formed by the flexible resin and the elastic filler on the yarn. The foaming coating can improve the softness and rebound resilience of the yarn; the foaming coating contains thermal expansion microspheres, so that the bulkiness and the air permeability of the yarn can be improved after expansion; and the curing agent in the foaming coating is crosslinked with the foaming resin, so that the hydrolysis resistance and the scratching resistance of the foaming coating can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of yarn post-processing, and in particular to a foamed yarn and a preparation method thereof. Background Art

[0002] Fluffiness is an important indicator of yarn performance. The fluffier the yarn, the more air it can preserve, slow down air mobility, and improve thermal insulation. At the same time, yarn with high fluffiness is softer, less prone to compaction, and more comfortable to wear. Chinese invention patent application number 202110677568.7 discloses a method for producing foamed microporous thermal insulation fibers, in which foamable microspheres are added to polyester slices for melt spinning. During the spinning process, the microspheres are foamed to produce multiple closed micropores inside the fibers, thereby improving fluffiness and warmth retention. However, the preparation method is complex, has high requirements for the control of the foamable microspheres and temperature, and the bubbles are easily broken, affecting the mechanical strength of the yarn. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a foamed yarn having both mechanical strength and bulkiness and a preparation method thereof.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing foamed yarn, comprising the following steps: sizing the yarn in a mixture of a curing agent and a slurry, and then curing and foaming the yarn in sequence to obtain the foamed yarn; the slurry includes a foaming resin and heat-expandable microspheres.

[0005] Another technical solution adopted by the present invention is: a foamed yarn prepared by adopting the above-mentioned method for preparing the foamed yarn.

[0006] The beneficial effects of the present invention are as follows: in the preparation method of the foamed yarn of the present invention, the slurry is solidified and foamed to form a foamed coating composed of a flexible resin and an elastic filler on the yarn. The foamed coating can improve the softness and resilience of the yarn; the foamed coating contains heat-expandable microspheres, which can improve the fluffiness and air permeability of the yarn after expansion; the curing agent in the foamed coating is cross-linked with the foamed resin, which can improve the hydrolysis resistance and flexural resistance of the foamed coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 Shown is a finished product diagram of a foamed yarn according to a specific embodiment of the present invention;

[0008] Figure 2 Shown is a microstructure diagram of a foamed yarn according to a specific embodiment of the present invention;

[0009] Figure 3 Shown is a schematic diagram of a sizing device according to a specific embodiment of the present invention;

[0010] Description of labels:

[0011] 1. Yarn; 2. Sizing tank; 3. Immersed roller; 4. Sizing roller; 5. Oven. DETAILED DESCRIPTION

[0012] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0013] Please refer to Figure 1 as well as Figure 2 A method for preparing a foamed yarn comprises the following steps: sizing the yarn in a mixed solution of a curing agent and a slurry, and then sequentially curing and foaming the yarn to obtain the foamed yarn; the slurry comprises a foaming resin and heat-expandable microspheres.

[0014] Among them, the yarn is a yarn bundle.

[0015] From the above description, it can be seen that the beneficial effects of the present invention are as follows: the present invention sizes the yarn in a slurry containing a foaming resin and heat-expandable microspheres, and after curing and foaming, forms a foaming coating composed of a flexible resin and an elastic filler on the yarn. The foaming coating fully wraps the yarn, so that the yarn has good softness and resilience; at the same time, the heat-expandable microspheres in the yarn foam, so that the yarn expands and becomes fluffy, which can improve its fluffiness and air permeability; the curing agent cross-links with the foaming resin, which can improve the hydrolysis resistance and flexural resistance of the foaming coating, and avoid affecting the service life of the yarn due to insufficient strength of the foaming coating.

[0016] Furthermore, the weight of the curing agent is 1 to 3% of the weight of the slurry.

[0017] Furthermore, the curing agent is any one of an isocyanate curing agent, a carbodiimide curing agent and an aziridine curing agent.

[0018] From the above description, it can be seen that isocyanate curing agents, carbodiimide curing agents and aziridine curing agents have advantages in price and printing operation health.

[0019] Preferably, the curing agent is an isocyanate curing agent.

[0020] From the above description, it can be seen that if the amount of curing agent added is too low, the hydrolysis resistance and flexural resistance of the foaming coating will be reduced; if the amount of curing agent added is too high, it will easily lead to excessive cross-linking of the coating, resulting in changes in appearance and hardness properties, and reducing the elasticity and toughness of the foaming coating.

[0021] Furthermore, the slurry includes 40-70% of foaming resin and 3-11% of heat-expandable microspheres by weight.

[0022] Preferably, the slurry includes 50-60% foaming resin and 5-8% heat-expandable microspheres by weight.

[0023] From the above description, it can be seen that if the amount of foaming resin added is too low, the slurry viscosity will be too low to be sized; if the amount added is too high, the viscosity of the foaming coating will be too high, and it will be difficult to level after sizing, resulting in uneven distribution of yarn thickness and the phenomenon of yarns sticking to each other.

[0024] If the amount of heat-expandable microspheres added is too low, the yarn expansion effect cannot be achieved, and the foaming coating thickness will be insufficient, and the elasticity and softness will be poor; if the amount added is too high, it will be prone to uneven heating during foaming, forming yarns of uneven thickness and low strength.

[0025] Furthermore, the foaming resin is a water-based polyurethane foaming resin.

[0026] From the above description, it can be seen that water-based polyurethane foaming resin can ensure that the coating is water-resistant, flex-resistant, soft and elastic. In addition, the use of water-based polyurethane resin for foaming is non-toxic, odorless, and green and environmentally friendly.

[0027] Furthermore, the diameter of the heat-expandable microspheres before foaming is 10-13 μm, and the microspheres can expand to a maximum of 60 times the original volume after heating.

[0028] Furthermore, the slurry also includes additives.

[0029] Furthermore, the additive includes at least one of a pH regulator, a solvent, a defoaming agent and a wetting and dispersing agent.

[0030] From the above description, it can be seen that the pH adjuster is used to adjust the pH value of the slurry. The pH value is preferably between 6 and 8 to keep the foaming slurry neutral and avoid incompatible precipitation of added materials due to the pH of the foaming slurry being too high or too low, thereby affecting the stability of the slurry.

[0031] Defoaming agents can prevent bubbles from forming during the mixing and printing process of the slurry. When the bubbles burst, defects will occur on the coating surface, affecting the appearance of the coating.

[0032] Wetting and dispersing agents can adjust the dispersibility, wettability and leveling ability of the slurry.

[0033] Furthermore, the solvent is ethylene glycol.

[0034] From the above description, it can be seen that ethylene glycol can adjust the solubility and slow drying properties of the slurry to prevent the slurry from drying too quickly in the air.

[0035] Furthermore, the slurry includes, by weight percentage, 40-70% foaming resin, 3-11% heat-expandable microspheres, 0.1-1% pH regulator, 2-6% solvent, 0.5-1.8% defoamer, 2-5% wetting dispersant and 1-5% fumed silica.

[0036] Furthermore, the slurry is composed of 50-60% foaming resin, 5-8% heat-expandable microspheres, 0.1-1% pH regulator, 2-6% solvent, 0.5-1.8% defoamer, 2-5% wetting dispersant, 1-5% fumed silica and the balance water, by weight percentage.

[0037] From the above description, it can be seen that if the content of the wetting and dispersing agent is too low, the thermal expansion microspheres will be unevenly dispersed and the foaming slurry viscosity will be too low to be sizing; if the content of the wetting and dispersing agent is too high, the dispersants will associate with each other, the slurry viscosity will be too high, the leveling effect will be poor, and the yarn thickness distribution will be uneven.

[0038] Fumed silica is used to adjust the rheology and thixotropy of the product.

[0039] Furthermore, the viscosity of the slurry is 6000-21000 cps.

[0040] Furthermore, the specific steps of sizing the yarn are as follows: the yarn is in a straight and taut state and enters into a mixture of a sizing agent and a curing agent for sizing, and the speed of the yarn during sizing is 25 to 35 m / min.

[0041] Please refer to Figure 3 Furthermore, when sizing the yarn, the yarn head passes through the yarn guide porcelain seat, and the yarn passes through the tension yarn guide, the immersion roller and the slurry pressure roller in sequence and enters the oven; the immersion roller is arranged in the slurry tank.

[0042] It can be seen from the above description that the cooperation of the above devices can ensure that the yarn is sized in a straight and taut state, thereby ensuring the uniformity of the sizing.

[0043] Furthermore, the sized yarn is passed through a squeezing roller to squeeze out excess sizing, and then solidified.

[0044] Furthermore, the liquid carrying rate of the yarn after sizing by the sizing roller is 2-6wt%.

[0045] Furthermore, the curing conditions are: keeping warm at 120-140° C. for 2-10 minutes.

[0046] Furthermore, the foaming conditions are: keeping warm at 160-180° C. for 2-10 minutes.

[0047] From the above description, it can be seen that foaming can remove moisture on the one hand, making it easier for the yarn to be curled in the later stage; on the other hand, a foaming coating can be prepared to increase the softness and resilience of the yarn, and improve its fluffiness and air permeability.

[0048] Furthermore, a GA392 single yarn sizing machine of Jiangyin Tongyuan Spinning Machine Co., Ltd. is used for foaming.

[0049] From the above description, it can be seen that the equipment has hot air circulation and automatic dehumidification functions, and can set the temperature and display the temperature in real time to ensure uniform and stable foaming temperature. It also has its own oven, and can be used for foaming after the coating is cured, eliminating the step of yarn transfer, ensuring the continuity of the experiment while avoiding the waste of manpower, time and energy.

[0050] Another technical solution adopted by the present invention is: the foamed yarn is prepared by adopting the above-mentioned method for preparing the foamed yarn.

[0051] The raw materials used in the following examples are shown in Table 1.

[0052] Table 1

[0053]

[0054] Please refer to Figures 1 to 3 Embodiment 1 of the present invention is: a method for preparing a foamed yarn, comprising the following steps:

[0055] S1. Prepare slurry: mix 55 kg of foaming resin, 7 kg of heat-expandable microspheres, 0.5 kg of pH adjuster, 4 kg of solvent, 1.2 kg of defoamer, 3.5 kg of wetting dispersant, 3 kg of fumed silica and 25.8 kg of water, and disperse them until the viscosity is 9090 cps to obtain slurry; add 2 kg of curing agent to the slurry.

[0056] S2, sizing: a GA392 single yarn sizing machine produced by Jiangyin Tongyuan Spinning Machine Co., Ltd. is used, the sizing machine comprises an immersion roller 3, a sizing roller 4 and a drying oven 5 which are arranged in sequence along the moving direction of the yarn 1, and the immersion roller 3 is arranged in the sizing tank 2;

[0057] S21: cleaning the sponge of the squeezing roller 4 with hot water, passing the yarn 1 through the tension yarn guide, the immersion roller 3 and the squeezing roller 4 in sequence, the liquid carrying rate before squeezing is 8wt%, and the liquid carrying rate after squeezing is 5wt%;

[0058] S22: tie the thread end to the screw of the oven 5, and start pre-winding after tying it tightly, wind the yarn onto the rotating cage, and the winding rotating cage automatically rotates 320 circles; find the thread end tied to the screw of the oven 5, take the thread end out, and wind it manually; test the yarn winding, check the yarn tension, adjust the yarn feeding rate, and keep the yarn in a straight and taut state;

[0059] S23: After the trial run goes smoothly and there is no frequent short line, pour the slurry into the slurry tank 2 for sizing, and the yarn speed is 30m / min; after the sizing is completed, take out the yarn, take out the slurry tank 2, clean the slurry inside, take out the yarn on the rotating cage, and clean the residual yarn; remove the yarn tube to obtain the foamed slurry coated yarn.

[0060] S3. Curing: Place the foamed slurry coated yarn in a sizing machine oven and cure it at 130°C for 5 minutes.

[0061] S4. Foaming: Place the foamed slurry coated yarn in a sizing machine oven and keep it at 170°C for 5 minutes.

[0062] Embodiment 2 of the present invention is:

[0063] The only difference between Example 2 and Example 1 is: S1, preparing slurry: 40 kg of foaming resin, 3 kg of heat-expandable microspheres, 0.1 kg of pH adjuster, 2 kg of solvent, 0.5 kg of defoamer, 2 kg of wetting dispersant, 1 kg of fumed silica and 51.4 kg of water are mixed and dispersed to a viscosity of 6000 cps to obtain slurry; 1 kg of curing agent is added to the slurry.

[0064] The yarn speed in S23 is 25 m / min. The curing condition in S3 is: curing at 120° C. for 10 min. The foaming condition in S4 is: keeping warm at 160° C. for 10 min.

[0065] Embodiment 3 of the present invention is:

[0066] The only difference between Example 3 and Example 1 is: S1, preparing slurry: 70kg of foaming resin, 11kg of heat-expandable microspheres, 1kg of pH adjuster, 6kg of solvent, 1.8kg of defoamer, 5kg of wetting dispersant, 5kg of fumed silica and 0.2kg of water are mixed and dispersed to a viscosity of 21000cps to obtain slurry; 3kg of curing agent is added to the slurry.

[0067] The yarn speed in S23 is 35 m / min. The curing condition in S3 is: curing at 140° C. for 2 min. The foaming condition in S4 is: keeping warm at 180° C. for 2 min.

[0068] Comparative Example 1 of the present invention is:

[0069] The only difference between Comparative Example 1 and Example 1 is that the mass of the defoamer in S1 is 0.1 kg, the mass of water is 26.9 kg, and the viscosity of the slurry is 9010 cps.

[0070] Comparative Example 2 of the present invention is:

[0071] The only difference between Comparative Example 2 and Example 1 is that the mass of the wetting dispersant in S1 is 8 kg, the mass of water is 21.3 kg, and the viscosity of the slurry is 27200 cps.

[0072] Comparative Example 3 of the present invention is:

[0073] The only difference between Comparative Example 3 and Example 1 is that the mass of the wetting dispersant in S1 is 1 kg, the mass of water is 28.3 kg, the mass of the curing agent is 0.5 kg, and the viscosity of the slurry is 10000 cps.

[0074] Comparative Example 4 of the present invention is:

[0075] The only difference between Comparative Example 4 and Example 1 is that the mass of the foaming resin in S1 is 80 kg, the mass of water is 0.8 kg, the mass of the curing agent is 3 kg, and the viscosity of the slurry is 31000 cps.

[0076] The performance of the yarns prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was tested. The test results are shown in Table 2, and the test methods are shown in Table 3.

[0077] Table 2

[0078]

[0079] Table 3

[0080] Test items Test Method Yarn thickness distribution Visual Foaming height TECLOCK SM-114 Fan loss Scraper scrapes off the yarn surface coating Adhesion Visual Breaking strength Measured according to the method specified in GB / T 3916-2013 Elongation Measured according to the method specified in GB / T 3916-2013 Fluffiness GB / T 10288-2016

[0081] In summary, the foamed yarn and the preparation method thereof provided by the present invention have the following advantages:

[0082] (1) After sizing, a foam coating composed of a flexible resin and an elastic filler is formed on the yarn, which is then cured and foamed. Curing can improve the hydrolysis resistance and flexural resistance of the yarn, and the foamed yarn has good softness and resilience.

[0083] (2) The foaming coating contains heat-expandable microspheres, which expand the yarn and make it fluffy after foaming, thereby improving its fluffiness and air permeability.

[0084] (3) By controlling the content of each component in the slurry, the viscosity, strength, stability, foaming thickness and other properties of the slurry are balanced to prevent the yarns from sticking to each other.

[0085] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a foamed yarn, characterized in that: The method comprises the following steps: sizing the yarn in a mixed liquid of a curing agent and a slurry, and then sequentially curing and foaming to obtain the foamed yarn; the slurry comprises a foaming resin and heat-expandable microspheres.

2. The method for preparing the foamed yarn according to claim 1, characterized in that: In terms of weight percentage, the slurry includes 40-70% of foaming resin and 3-11% of heat-expandable microspheres.

3. The method for preparing the foamed yarn according to claim 1, characterized in that: The slurry also includes additives.

4. The method for preparing the foamed yarn according to claim 3, characterized in that: The additive includes at least one of a pH adjuster, a solvent, a defoamer and a wetting and dispersing agent.

5. The method for preparing the foamed yarn according to claim 1, characterized in that: The viscosity of the slurry is 6000-21000 cps.

6. The method for preparing the foamed yarn according to claim 1, characterized in that: The specific steps of sizing the yarn are as follows: the yarn is in a straight and tight state and enters the slurry for sizing, and the speed of the yarn during sizing is 25-35m / min.

7. The method for preparing the foamed yarn according to claim 1, characterized in that: The sized yarn is passed through a sizing roller to squeeze out excess sizing, and then solidified.

8. The method for preparing the foamed yarn according to claim 1, characterized in that: The curing conditions are: keeping warm at 120-140° C. for 2-10 minutes.

9. The method for preparing the foamed yarn according to claim 1, characterized in that: The foaming conditions are: keeping warm at 160-180° C. for 2-10 minutes.

10. A foamed yarn prepared by the method for preparing a foamed yarn according to any one of claims 1 to 9.

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