Controllable porous pure wool flocculus solidified by enzyme and preparation method of controllable porous pure wool flocculus

Abstract

The invention discloses a controllable porous pure wool flocculus cured by enzyme and a preparation method thereof, and belongs to the technical field of textile materials.According to the method, wool fibers and polylactic acid fibers are treated into a mixed fiber net, and the wool fibers account for 80-95% of the total mass of the wool fibers and the polylactic acid fibers; then carrying out heat treatment on the mixed fiber net under 0.1-0.3 MPa for a plurality of seconds to obtain primarily heat-set wool flocculus; finally, the wool flocculus subjected to preliminary heat setting is padded in a transglutaminase solution at the temperature of 20-30 DEG C, then heat preservation is conducted at the temperature of 40-55 DEG C, polylactic acid fibers are removed, then after finishing is conducted, and the controllable porous pure wool flocculus is obtained and can have a permanent stable structure and also can keep high filling power and excellent air permeability on the premise that non-natural components are not introduced.

Description

Technical Field

[0001] This invention belongs to the field of textile materials technology, specifically a controllable porous pure wool wadding using enzyme curing and its preparation method. Background Technology

[0002] Wool, as a natural and comfortable insulating material, is widely used in everyday clothing and outdoor sports. However, pure wool wadding faces a long-standing technical challenge: insufficient structural stability. Traditional physical processing techniques result in a lack of effective bonding between wool fibers. After prolonged use or washing, the fibers tend to shift and loosen, leading to problems such as clumping, deformation, and thinning of the wadding, severely impacting its uniformity of warmth and lifespan.

[0003] To address this issue, several different technical approaches have been proposed: First, adding synthetic fibers: Represented by Chinese invention patent CN106283384A, entitled "Composite Antibacterial Wool Fluff and its Preparation Method," this involves mixing low-melting-point synthetic fibers such as polyester and polyethylene into wool, followed by thermal bonding to form a stable structure. While this method improves stability, its fundamental drawback is the sacrifice of the material's natural properties; the product is no longer 100% pure wool, and synthetic fibers are difficult to degrade, contradicting current environmental trends. Second, pure chemical crosslinking: This involves directly treating the pure wool fiber web with thermosetting resins and chemical crosslinking agents. Although this method can form bonds, the crosslinking process is difficult to control, easily leading to excessive fiber adhesion, causing the fluff to harden and lose its original fluffiness, softness, and breathability. Third, pure biological enzymatic crosslinking: For example, utilizing the catalytic crosslinking properties of transglutaminase, this method is applied to the processing of damaged wool protein fibers and fabrics, as well as other specialty animal fibers, aiming to maintain and improve the mechanical properties of fibers and fabrics (such as breaking strength, breaking elongation, and felting ball density). However, this method has a drawback: during wet processing, the loose wool fiber web collapses due to a lack of support. Enzymatic crosslinking fixes precisely this collapsed, low-loft structure, resulting in a stable product with poor loft and insulation performance.

[0004] Therefore, how to prepare a pure wool wadding that has a permanently stable structure while maintaining high loft and excellent breathability without introducing non-natural ingredients is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a controllable porous pure wool wadding using enzyme curing and its preparation method, thereby solving the problem of preparing a pure wool wadding with both a permanently stable structure and maintaining high fluffiness and excellent breathability without introducing non-natural components, and possessing a stable porous structure.

[0006] This invention is achieved through the following technical solution: A method for preparing controllable porous pure wool wadding using enzyme solidification specifically includes the following steps: Step 1: Process wool fibers and polylactic acid fibers into a mixed fiber web, with wool fibers accounting for 80-95% of the total mass of wool fibers and polylactic acid fibers; Step 2: Heat-treat the mixed fiber web at 0.1-0.3 MPa for several seconds to obtain a preliminarily heat-set wool wadding; Step 3: The pre-heat-set wool wadding is immersed in a transglutaminase solution at 20-30℃, then kept at 40-55℃, and then polylactic acid fibers are removed. After finishing, controllable porous pure wool wadding is obtained.

[0007] A further improvement of the present invention is that: The wool fiber in step 1 is a short wool fiber with an average length of 50-70 mm, and the polylactic acid fiber is a short polylactic acid fiber with a length of 38-51 mm and a fineness of 2-4 dtex. First, wool fibers and polylactic acid fibers are evenly mixed, and then opened, combed and cross-laid in sequence to form a mixed fiber web.

[0008] In step 2, the heat treatment temperature is 120-135℃, and the heat treatment is carried out at this temperature for 5-15 seconds to obtain the wool wadding that has been preliminarily heat-set.

[0009] The transglutaminase solution described in step 3 has a pH of 6.0-7.5, an enzyme activity of 50-100 U / g, and contains proline or glycine dissolved in it, with proline or glycine accounting for 0.1-5% of the total mass of the transglutaminase solution.

[0010] Step 3: After immersing the pre-heat-set wool wadding in a transglutaminase solution, keep it at 40-55℃ for 20-40 minutes.

[0011] Step 3: Wash the wool wadding obtained after heat preservation in deionized water at 60-80℃ until polylactic acid is removed, and then finish it.

[0012] A controllable porous pure wool wadding obtained by the method for preparing controllable porous pure wool wadding using enzyme curing as described in any one of the above.

[0013] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a method for preparing controllable porous pure wool wadding using enzyme solidification. After heat treatment of a mixed fiber web composed of wool fibers and polylactic acid (PLA) fibers, the PLA softens and partially melts at the intersections, adhering to each other to form a three-dimensional, porous, and relatively rigid temporary framework. This framework locks the wool fibers in a predetermined fluffy state, providing crucial structural support for subsequent padding, fundamentally solving the problem of pure wool fiber webs easily collapsing during wet processing. Low-temperature padding at 20-30℃ ensures that enzyme molecules fully penetrate the interior of the wadding and are uniformly adsorbed onto the surface of the wool fibers. Due to the low temperature at this stage, the cross-linking reaction rate between the enzyme and the wool fibers is extremely slow; the process is primarily one of enzyme penetration. During heat treatment at 40-55℃, the TG enzyme is rapidly activated, initiating a highly efficient catalytic cross-linking reaction between wool fiber keratin molecules. Because the wool fibers are stretched and maintained in a fluffy three-dimensional state by the PLA temporary framework, the enzyme cross-linking fixes precisely this highly fluffy, ideal structure. It establishes uniform and stable covalent bonds between countless wool fiber contact points, avoiding excessive local adhesion, much like a miniature rivet, permanently solidifying the fluffy structure. This invention combines the physical support of the PLA skeleton with the biochemical solidification of enzyme cross-linking, achieving a unity of pure wool and high performance. The final product is 100% pure wool, fully biodegradable, and perfectly preserves the natural properties of wool; at the same time, its structural stability far exceeds that of traditional pure wool products, making it less prone to clumping and deformation, achieving precise control and permanent fixation of the fluffy structure. This invention first constructs a temporary skeleton to support the fluff, and then uses enzymes to permanently lock the structure, completely solving the collapse problem caused by pure enzyme cross-linking, achieving unprecedented high fluffiness and excellent warmth and breathability. The entire process of this invention uses only wool, biodegradable PLA, and bio-enzymes, making the process green and environmentally friendly, in line with the future direction of material development. Attached Figure Description

[0014] Figure 1 This is a photograph of the pure wool wadding from Example 1 of the present invention before washing, obtained by means of an optical microscope.

[0015] Figure 2 The image shows a pure wool wadding sheet from Example 1 of the present invention after 20 standard water washes, obtained by means of an optical microscope.

[0016] Figure 3 This is a photograph of the pure wool wadding of Comparative Example 1 of the present invention, obtained by means of an optical microscope.

[0017] Figure 4 The image shows a physical photograph of the pure wool wadding of Comparative Example 2 of the present invention obtained by means of an optical microscope.

[0018] Figure 5 for Figure 1The microstructure of a local area magnified 60 times. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0020] This invention discloses a method for preparing controllable porous pure wool wadding using enzyme solidification, specifically comprising the following steps: Step 1: Preparation of the hybrid fiber web: Wool staple fibers (average length 50-70mm) are uniformly mixed with polylactic acid (PLA) staple fibers, with wool staple fibers accounting for 80-95% of the total mass. Through opening, combing and cross-laying, a mixed fiber web with a preset weight is formed.

[0021] PLA short fibers have a melting point of 150-170℃, a fiber length of 38-51mm, and a fineness of 2-4dtex.

[0022] Step 2: Preliminary heat setting: The mixed fiber web obtained in step 1 is subjected to a brief heat treatment at a temperature of 120-135℃ and a pressure of 0.1-0.3 MPa for 5-15 seconds to obtain a preliminarily heat-set wool wadding.

[0023] The core function of this step is to soften and partially melt the PLA at the intersections, causing them to adhere together and form a three-dimensional, porous, and relatively rigid temporary skeleton. This skeleton locks the wool fibers in a pre-set fluffy state, providing crucial structural support for subsequent wet (paddling) processing, fundamentally solving the problem of pure wool fiber webs easily collapsing during wet processing.

[0024] Step 3: Enzyme immobilization treatment (core step): Step 3.1 - Enzyme activation and permeation: The wool wadding obtained in step 2 is immersed in a transglutaminase (TG enzyme) solution containing a penetrant using a two-dip, two-nip method. Specifically, the TG enzyme is first dissolved in water, and the pH of the resulting solution is adjusted to 6.0-7.5, controlling the enzyme activity to 50-100 U / g to obtain the TG enzyme solution. Then, proline or glycine, a penetrant, is added to dissolve the enzyme, with the amount added being 0.1-5% of the total mass of the enzyme solution. The immersion temperature is controlled at 20-30℃ to ensure that the enzyme molecules fully penetrate into the interior of the wadding and are uniformly adsorbed on the surface of the wool fibers. Due to the low temperature at this stage, the cross-linking reaction rate between the enzyme and the wool fibers is extremely slow, and the process is mainly one of enzyme penetration.

[0025] Step 3.2 - Controlling the reaction and cross-linking: Immediately place the impregnated wadding into a temperature-controlled oven and maintain a temperature of 40-55℃ for 20-40 minutes. At this temperature, the TG enzyme is rapidly activated, initiating a highly efficient catalytic cross-linking reaction between wool fiber keratin molecules. Since the wool fibers are already supported and maintained in a fluffy three-dimensional state by the PLA temporary framework, the enzyme cross-linking fixes precisely this highly fluffy, ideal structure. It establishes uniform and stable covalent bonds between countless wool fiber contact points, preventing excessive local adhesion, acting like miniature rivets to permanently solidify the fluffy structure.

[0026] Step 4: Skeleton Removal and Structure Release The wadding treated in step 3 is washed in hot water (60-80℃) until the PLA fibers are completely hydrolyzed and removed. At this point, the porous structure of pure wool, which is fixed by covalent bonds, is completely released.

[0027] Step 5: Post-processing: The obtained wadding is washed and dehydrated with clean water, and then subjected to routine softening and drying to finally obtain the controllable porous pure wool wadding.

[0028] The present invention also provides a controllable porous pure wool wadding prepared by the above method, wherein the wadding is composed of 100% pure wool, has a stable porous structure formed by enzymatic cross-linking, and retains more than 90% of its fluffiness after 20-40 water washes.

[0029] Example 1 A method for preparing controllable porous pure wool wadding using enzyme solidification specifically includes the following steps: Step 1: By weight, take 85 parts of wool short fiber (average length 60mm) and 15 parts of PLA short fiber (melting point 160℃, length 45mm, fineness 3dtex) and mix them. After opening, combing and cross-laying, a mixed fiber web of 250g / m² is formed.

[0030] Step 2: Hot-press the fiber web at 130℃ and 0.2MPa for 10 seconds to soften and bond the PLA, forming a stable temporary skeleton.

[0031] Step 3.1: Prepare TG enzyme solution (pH=6.0, control enzyme activity at 50 U / g), with proline as the penetrant, added at 2% of the total mass of the enzyme solution. Dip and nibble the wool wadding obtained in step 2 at 25°C to achieve a liquid retention rate (i.e., nip retention rate) of 80%, which ensures that the enzyme molecules fully penetrate into the wadding and are evenly adsorbed on the surface of the wool fibers.

[0032] Step 3.2: Treat the flocculent material in a 50℃ oven for 30 minutes.

[0033] Step 4: Wash the flocs repeatedly in 70℃ hot water until no PLA residue can be detected.

[0034] Step 5: Wash and dehydrate the wadding with clean water, perform routine softening and drying to obtain the controllable porous pure wool wadding.

[0035] Example 2 A method for preparing controllable porous pure wool wadding using enzyme solidification specifically includes the following steps: Step 1: By weight, take 80 parts of wool short fiber (average length 65mm) and 20 parts of PLA short fiber (melting point 165℃, length 48mm, fineness 2.5dtex) and mix them. After opening, combing and cross-laying, a mixed fiber web of 240g / m² is formed.

[0036] Step 2: Hot-press the fiber web at 125℃ and 0.25MPa for 12 seconds to soften and bond the PLA, forming a stable temporary skeleton.

[0037] Step 3.1: Prepare TG enzyme solution (pH=6.5, control enzyme activity to 70 U / g), add 2% proline (relative to the total mass of enzyme solution), and dip and rub the wool flakes obtained in step 2 twice at 25℃ to achieve a liquid retention rate of 80%.

[0038] Step 3.2: Treat the flocculent material in a 45℃ oven for 35 minutes.

[0039] Step 4: Wash the flocculent repeatedly in 75℃ hot water until no PLA residue can be detected.

[0040] Step 5: Wash and dehydrate the wadding with clean water, perform routine softening and drying to obtain the controllable porous pure wool wadding.

[0041] Example 3 A method for preparing controllable porous pure wool wadding using enzyme solidification specifically includes the following steps: Step 1: By weight, take 90 parts of wool short fiber (average length 55mm) and 10 parts of PLA short fiber (melting point 155℃, length 42mm, fineness 3.5dtex) and mix them. After opening, combing and cross-laying, a mixed fiber web of 260g / m² is formed.

[0042] Step 2: Hot-press the fiber web at 130℃ and 0.15MPa for 8 seconds to soften and bond the PLA, forming a stable temporary skeleton.

[0043] Step 3.1: Prepare TG enzyme solution (pH=7.2, control enzyme activity to 90 U / g), add 3% glycine (relative to the total mass of enzyme solution), and dip and rub the wool wadding obtained in step 2 twice at 25℃ to make the liquid retention rate 80%.

[0044] Step 3.2: Treat the flocculent material in a 50℃ oven for 25 minutes.

[0045] Step 4: Wash the flocs repeatedly in 70℃ hot water until no PLA residue can be detected.

[0046] Step 5: Wash and dehydrate the wadding with clean water, perform routine softening and drying to obtain the controllable porous pure wool wadding.

[0047] Comparative Example 1 (pure enzyme cross-linking): The short wool fibers from step 1 of Example 1 were directly enzymatically treated in step 3, and then in step 5 to obtain pure wool wadding.

[0048] like Figure 3 As shown, pure wool wadding has low loft and is prone to clumping.

[0049] Comparative Example 2 (Pure PLA Composite): The temporary skeleton from step 2 of Example 1 is subjected to conventional softening and drying to directly obtain wool / PLA composite wadding.

[0050] like Figure 4 As shown, the composite wadding feels stiff, has poor breathability, and is not pure wool.

[0051] Comparative Example 3: The product from Comparative Example 2 was exposed to humid air with a relative humidity of 60-80% and allowed to degrade PLA.

[0052] PLA initially has good fluffiness after degradation, but after 10 standard water washes, it collapses rapidly due to the lack of internal connections.

[0053] The pure wool wadding obtained in Example 1 was tested and found to be fluffy and soft to the touch. According to GB / T 10288—2016 "Test Method for Fluffiness of Textile Fibers", the initial fluffiness of the product in Example 1 was 18.0 mm. Figure 1 As shown; Figure 5 The microstructure of the white fibrous material is further demonstrated; the fibers are long, thin, and interwoven, exhibiting a stable porous morphology. The initial loft of the pure wool wadding in Comparative Example 1 was 10.0 mm, while the initial loft of the product in Example 1 was 1.8 times that of the control pure wool wadding (Comparative Example 1). After 20 standard washes, the loft of the product in Example 1 was 17.1 mm. Figure 2 As shown, the fluffiness retention rate was 95%, with no clumping.

Claims

1. A method for preparing controllable porous pure wool wadding using enzyme solidification, characterized in that, Includes the following steps: S1, wool fibers and polylactic acid fibers are processed into a mixed fiber web, with wool fibers accounting for 80-95% of the total mass of wool fibers and polylactic acid fibers; S2, heat-treat the mixed fiber web at 0.1-0.3 MPa for several seconds to obtain a preliminarily heat-set wool wadding; S3 involves immersing the pre-heat-set wool wadding in a transglutaminase solution at 20-30°C, then keeping it at 40-55°C to remove polylactic acid fibers, followed by finishing to obtain controllable porous pure wool wadding.

2. The method for preparing controllable porous pure wool wadding using enzyme solidification according to claim 1, characterized in that, The wool fiber mentioned in S1 is a short wool fiber with an average length of 50-70 mm; the polylactic acid fiber is a short polylactic acid fiber with a length of 38-51 mm and a fineness of 2-4 dtex.

3. The method for preparing controllable porous pure wool wadding using enzyme solidification according to claim 1, characterized in that, S1 first mixes wool fibers and polylactic acid fibers evenly, then opens, combs, and cross-lays the web in sequence to form a mixed fiber web.

4. The method for preparing controllable porous pure wool wadding using enzyme solidification according to claim 1, characterized in that, The heat treatment temperature in S2 is 120-135℃.

5. The method for preparing controllable porous pure wool wadding using enzyme solidification according to claim 4, characterized in that, S2 involves heat-treating the mixed fiber web at 0.1-0.3 MPa for 5-15 seconds to obtain a preliminarily heat-set wool wadding.

6. The method for preparing controllable porous pure wool wadding using enzyme solidification according to claim 1, characterized in that, The transglutaminase solution described in S3 has a pH of 6.0-7.5 and an enzyme activity of 50-100 U / g.

7. The method for preparing controllable porous pure wool wadding using enzyme solidification according to claim 6, characterized in that, The transglutaminase solution described in S3 contains proline or glycine dissolved in it, and the proline or glycine accounts for 0.1-5% of the total mass of the transglutaminase solution.

8. The method for preparing controllable porous pure wool wadding using enzyme solidification according to claim 1, characterized in that, S3 involves immersing the pre-heat-set wool wadding in a transglutaminase solution and then keeping it at 40-55℃ for 20-40 minutes.

9. The method for preparing controllable porous pure wool wadding using enzyme solidification according to claim 8, characterized in that, S3 washes the wool wadding obtained after heat preservation in deionized water at 60-80℃ until polylactic acid is removed, and then finishes it.

10. A controllable porous pure wool wadding obtained by the preparation method of controllable porous pure wool wadding using enzyme solidification as described in any one of claims 1 to 9.

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