Preparation method for fixing knitted fabric by using reinforcing band after ultrasonic splicing

Abstract

The invention relates to the field of textile materials, and discloses a preparation method for fixing knitted fabric through a reinforcing band after ultrasonic splicing, and the preparation method comprises the following steps: S1, preparing materials: selecting proper knitted fabric and reinforcing band materials, and coating the materials with a hot melt adhesive or an adhesive; s2, ultrasonic splicing: seamlessly splicing the two pieces of knitted fabric along a preset splicing line through ultrasonic welding equipment; s3, reinforcing band fixing, wherein a reinforcing band is laid at the splicing position along a preset path, and the reinforcing band is heated through a hot-air blower; s4, pressing and fixing a flat plate: applying pressure and temperature to the spliced part through a flat plate pressing machine; s5, post-treatment: performing post-treatment such as finishing and cutting on the spliced and fixed fabric to obtain a finished product. According to the invention, through a double reinforcement mechanism of ultrasonic splicing and the functional reinforcing band, the strength and durability of the splicing part are obviously improved, the reinforcing band structure and the hot melt adhesive can bear larger external force, and the service life of the product is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of textile materials, and specifically to a preparation method for fixing a knitted fabric after ultrasonic splicing with a reinforcing tape, which is particularly suitable for the seam strengthening treatment of sportswear, medical textiles and special protective equipment under high stress environments Background Art

[0002] Knitted fabrics are widely used in many fields due to their soft texture, excellent breathability and good elasticity. For example, in daily knitted clothing, they can provide a comfortable wearing experience; in home textile products, such as knitted sheets, their softness is highly favored

[0003] In the process of processing and producing knitted fabrics, traditional splicing methods usually involve sewing and hot pressing. Sewing not only leaves stitch marks, which destroys the overall aesthetics of the fabric, affects the touch and wearing experience. For example, on some high-end knitted clothing, the stitch marks may make the clothing look less delicate. At the same time, friction is likely to occur at the sewing stitch marks, aggravating local wear and shortening the service life of the fabric. In sportswear, the frequently rubbed stitch marks are prone to breakage; and during hot pressing, the high temperature is likely to damage the fiber structure of the knitted fabric and change the fabric properties. For example, it weakens the elasticity and reduces the breathability. At the same time, the strength and durability of the hot-pressed splicing are limited, and in high-stress or complex stress environments, such as industrial protective clothing, it is easy to split and delaminate

[0004] There are three major technical bottlenecks in the traditional splicing process of knitted fabrics

[0005] Defects in the sewing process: When using a #14 needle flat-sewing machine (stitch density 10 stitches / cm), the seam breaking strength is only 95±3N, and the dynamic bending life of the seams of sportswear is less than 3500 times due to stitch friction

[0006] Limitations of the hot-pressing process: At a hot-pressing temperature of 160°C, the elastic recovery rate of spandex fabric decreases by 28%, and the peel strength is only 8.5N / cm. The seam displacement reaches 0.8mm in a humid and hot environment

[0007] Insufficiencies of ultrasonic technology: After conventional 30kHz ultrasonic splicing, the seam breaking stress is 120N, and the strength retention rate drops to 82% after 50 washes, which cannot meet the requirement of 200N-class seam strength for protective clothing Summary of the Invention

[0008] In view of the deficiencies of the prior art, the present invention provides a preparation method for fixing a knitted fabric after ultrasonic splicing with a reinforcing tape, which solves the problem of poor stability of the fabric after splicing

[0009] To achieve the above objectives, the present invention is realized through the following technical solutions: A preparation method for fixing a knitted fabric after ultrasonic splicing with a reinforcing tape, comprising the following steps

[0010] S1. Material preparation: It is necessary to select knitted fabrics, reinforcement tapes, and hot melt adhesives respectively;

[0011] S2. Ultrasonic splicing: Use advanced ultrasonic welding equipment to splice two knitted fabrics along the predetermined splicing line. The ultrasonic splicing parameters of the equipment are optimized, the frequency is set at 20 kHz - 40 kHz, the amplitude is 20 μm - 80 μm, and the pressure is 0.1 MPa - 0.5 MPa to ensure stable and reliable splicing;

[0012] S3. Reinforcement tape fixation: Lay a straight or curved reinforcement tape at the splicing position as required, and heat the reinforcement tape with a hot air blower. The temperature is controlled at 380 °C - 420 °C, and the time is 5 s - 10 s to melt the hot melt adhesive and initially bond the reinforcement tape to the knitted fabric;

[0013] S4. Flat pressing and ironing fixation: Then use a flat pressing and ironing machine for further fixation. The temperature is 140 - 160 °C, the pressure is 2.5 - 4.5 kg, and the time is 15 - 25 s to allow the hot melt adhesive to fully penetrate the fabric fiber structure;

[0014] S5. Post - treatment: Carry out finishing treatment procedures on the spliced and fixed fabric. The finishing includes removing impurities and fluff, smoothing the splicing position, ensuring the flatness and smoothness of the fabric surface, and cutting the fabric into appropriate sizes and shapes according to the product design requirements to obtain the finished product.

[0015] Preferably, in the above - mentioned S1, the selection of the knitted fabric is specifically as follows: The weft - knitted fabric has good elasticity and softness, and the warp - knitted fabric has excellent longitudinal tensile strength. Select reasonably according to product requirements to ensure that the fabric has corresponding properties. For example, the weft - knitted fabric can be selected for making underwear, while the warp - knitted fabric can be selected for making sports protectors that require a certain degree of support.

[0016] Preferably, in the above - mentioned S1, the selection of the reinforcement tape is specifically as follows: A multi - layer structure reinforcement tape made of high - strength fiber materials (such as polyamide fibers) is adopted, which includes at least one high - strength fiber layer and one elastic fiber layer. The high - strength fiber layer provides support and reinforcement, and the elastic fiber layer matches the elasticity of the knitted fabric. At the same time, the width of the reinforcement tape is 10 - 15 mm, the thickness is 0.1 mm - 0.3 mm, and the surface is coated with a hot melt adhesive that has good compatibility, strong adhesion, and high temperature resistance with the knitted fabric, and can be adjusted according to actual needs.

[0017] Preferably, in the above - mentioned S1, the selection of the hot melt adhesive is specifically as follows: Select a suitable hot melt adhesive according to the material of the knitted fabric and the requirements of subsequent processing temperature to ensure stable bonding between the reinforcement tape and the fabric.

[0018] The core innovation point of the present invention lies in constructing a synergistic strengthening system of ultrasonic pre - welding + gradient - type reinforcement tape composite, specifically including:

[0019] Gradient-strengthened belt structure (Claim 1)

[0020] It consists of a polyamide high-strength fiber layer (thickness ratio: 40 - 60%), an elastic fiber layer (thickness ratio: 20 - 30%), and a hot-melt adhesive layer (thickness ratio: 15 - 25%) to form a three-dimensional composite structure ( Figure 3 );

[0021] By adjusting the ratio of high-strength / elastic fiber layers (Claim 2), a gradient matching of tensile strength (180 - 220 N) and elongation at break (50 - 120%) is achieved.

[0022] Optimized combination of process parameters

[0023] Ultrasonic welding adopts a frequency-amplitude-pressure linkage adjustment mechanism (Claim 3):

[0024]

[0025] Hot air curing adopts a temperature-time dynamic curve (Claim 4): Preheat at 380 °C for 3 s → Main curing at 400 °C for 5 s → Interface strengthening at 420 °C for 2 s.

[0026] Interface strengthening technology

[0027] In the flat ironing stage (Claim 5), hot pressing at 140 - 150 °C enables the hot-melt adhesive to penetrate into the pores of the fabric fibers (penetration depth ≥ 0.1 mm), forming a mechanical-chemical double anchoring effect.

[0028] The present invention provides a preparation method for fixing a knitted fabric with a strengthened belt after ultrasonic splicing. It has the following beneficial effects:

[0029] 1. Through the double strengthening mechanism of ultrasonic splicing and the functionalized strengthened belt (three-layer composite structure: high-strength fiber + hot-melt adhesive layer + elastic substrate), the strength and durability of the splicing part are significantly improved. The structure of the strengthened belt and the hot-melt adhesive bonding can withstand greater external forces, extending the service life of the product.

[0030] 2. The present invention adopts a stitchless ultrasonic splicing and a low-thickness strengthened belt composite process. Both operations are seamless technologies, avoiding the visual discontinuity and tactile hardening problems caused by traditional sewing, maintaining the natural beauty and soft touch of the knitted fabric, and meeting the requirements of consumers for appearance and comfort.

[0031] 3. Through the integrated process design of continuous ultrasonic welding and synchronous bonding of the strengthened belt, the splicing and fixing processes are fast and efficient, suitable for large-scale industrial production, helping to improve production efficiency and reduce costs.

[0032] 4. The present invention supports multi-dimensional customization design of the reinforcement belt, with adjustable width, selectable elongation at break, and hot melt adhesives of different types adapted to the polarity of different fabrics, which can meet the differential splicing requirements in the fields of sportswear, medical textiles, and special protection, etc., and has wide applicability.

[0033] 5. The present invention combines a weather-resistant formula of hot melt adhesive with an interface strengthening structure to provide additional stability for knitted fabrics, with stable performance in different environments to ensure splicing quality.

[0034] 6. Breakthrough in mechanical properties:

[0035] (1). The seam breaking strength reaches 180 - 220 N (an increase of 90 - 130% compared with the traditional process), and the dynamic bending life > 8000 times;

[0036] (2). The seam displacement in a humid and hot environment ≤ 0.3 mm, and the strength retention rate after 50 washes ≥ 95%.

[0037] 7. Innovation in process:

[0038] (1) Integrate ultrasonic welding (15 m / min) with the synchronous laminating technology of the reinforcement belt, with the sewing efficiency increased by 87% compared with the traditional process;

[0039] (2) The consumption of hot melt adhesive is reduced by 40%, and the energy consumption cost is saved by 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is the flowchart of the preparation method of the present invention;

[0041] Figure 2 is the schematic diagram of ultrasonic splicing of knitted fabrics in the present invention;

[0042] Figure 3 is the schematic diagram of the distribution of the reinforcement belt in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] Embodiment 1:

[0045] Please refer to Att Figure 1 -Att Figure 3 , Embodiment 1 of the present invention provides a preparation method for fixing a knitted fabric after ultrasonic splicing with a reinforcement belt, including the following steps:

[0046] S1. Material preparation: Select polyester fiber knitted fabric. The reinforcing belt material is polyamide fiber composite high-performance hot melt adhesive. The reinforcing belt has a three-layer structure, with a high-strength polyamide fiber layer in the middle and elastic fiber layers on the upper and lower sides. The width is 10 - 15 mm and the thickness is 0.1 - 0.3 mm;

[0047] Systematic material selection

[0048]

[0049] S2. Ultrasonic welding parameter optimization matrix

[0050] Establish a dynamic matching model between material thickness (0.5 - 2.2 mm) and process parameters:

[0051] P = k·(f / 30)^1.2·(A / 50)^0.8·(d / 1.5)^0.5

[0052] Where: P is the welding strength (N / cm), k is the material coefficient (polyester = 1.0, spandex = 0.8)

[0053] 1. Core claim: The synergistic effect of ultrasonic frequency 28 - 35 kHz and the orthogonal braided structure of the reinforcing belt achieves the technical effect that the seam fracture stress ≥ 180 N.

[0054] 2. Differentiated claim: Limit the nano-reinforced phase content of the hot melt adhesive (5 - 8 wt%) to ensure the bonding stability under the working conditions of -20°C to 80°C.

[0055] 3. Process claim: The pressure change curve of 0.3 → 0.4 MPa in the gradient pressing process enables the penetration depth of the hot melt adhesive to reach more than 85% of the fiber diameter;

[0056] S2. Ultrasonic splicing: Use an ultrasonic welding device with a frequency of 25 - 35 kHz, an amplitude of 50 - 70 μm, and a pressure of 0.25 - 0.4 MPa to splice the fabric;

[0057] S3. Fixing the reinforcing belt: Lay the reinforcing belt along a straight line, with the hot air blower temperature at 380°C - 420°C and the time at 5 s - 10 s for preliminary heating and fitting;

[0058] S4. Flat pressing and fixing: Use a flat pressing machine with a temperature of 140 - 150°C, a pressure of 0.25 - 0.45 MPa, and a time of 10 - 15 s for further fixing;

[0059] S5. Post-treatment: Sort and cut the fabric to obtain the finished product, and conduct a fracture test. The fracture strength at the splicing part is 60% higher than that of ordinary ultrasonic spliced fabrics, and the peel strength is 50% higher.

[0060] Beneficial effects of Example 1: Through the collaborative design of the high-strength polyamide intermediate layer and the elastic fiber layer in this Example 1, combined with the preliminary fitting with hot air at 380 - 420 °C and the secondary curing by flat pressing at 140 - 150 °C, the porosity of the splicing interface is < 3%, the peel strength is increased by 50%, and the seam fracture stress reaches 180 N (60% higher than the conventional process) after testing. The process is suitable for industrial continuous production (running speed > 15 m / min), the elastic recovery rate of the seam is > 92%, and it is resistant to 50 standard washes, suitable for high-stretch seam scenarios such as sportswear, and has both economy and high strength.

[0061] Example 2:

[0062] Example 1 of the present invention provides a preparation method for fixing a knitted fabric after ultrasonic splicing with a reinforcing tape, including the following steps:

[0063] S1. Material preparation: Select a warp-knitted spandex knitted fabric. The reinforcing tape is a hybrid woven coating of high-strength carbon fiber and elastic fiber with a special hot melt adhesive, with a width of 10 - 15 mm and a thickness of 0.1 - 0.3 mm;

[0064] S2. Ultrasonic welding: Set the frequency of the ultrasonic welding equipment at 25 - 35 kHz, the amplitude at 50 - 70 μm, and the pressure at 0.25 - 0.4 MPa for splicing;

[0065] S3. Fixing the reinforcing tape: Lay the reinforcing tape in a curve, at 380 °C - 420 °C, for a time of 5 s - 10 s, and heat for preliminary fitting;

[0066] S4. Flat pressing and fixing: The temperature of the flat pressing machine is 140 - 150 °C, the pressure is 0.25 - 0.45 MPa, and the time is 10 - 15 s for further fixing;

[0067] S4. Post-treatment: Fine finishing and cutting to obtain the finished product, and conduct inspection and testing.

[0068] Beneficial effects of Example 2: This Example 2 proposes a curve seam strengthening scheme for a warp-knitted spandex fabric with a carbon fiber hybrid reinforcing tape. It uses carbon fiber (≥30%) and elastic fiber woven and coated with a high heat melt index adhesive layer. By dispersing stress through an arc-shaped tape laying path, after hot melt curing at 380 - 420 °C, the seam tear resistance is increased by 70% (reaching 220 N), and the dynamic bending life > 10,000 times. The wet expansion displacement of the seam ≤ 0.3 mm (40 °C / 95% RH), and the peel strength remains > 18 N / cm, solving the problems of wrinkles and wet heat failure in the splicing of high-elastic fabrics on complex curved surfaces (such as tight-fitting clothes), and is suitable for the ergonomic design of high-end functional clothing.

[0069] Comparative experiment:

[0070] To scientifically verify the technological advancement of the present invention, the following comparative experiments are designed, covering three existing technologies: traditional sewing, hot press bonding, and ordinary ultrasonic splicing, and comparing the performance with Example 1 (seams of polyester sportswear) and Example 2 (seams of warp-knitted spandex tights) of the present invention.

[0071] I. Experimental Group Settings

[0072]

[0073]

[0074] II. Test Items and Experimental Methods

[0075] 1. Seam Breaking Strength

[0076] Test Standard: GB / T 3923.1 "Textiles - Tensile Properties of Fabrics - Part 1: Determination of Breaking Force and Elongation at Break"

[0077] Equipment: Universal Material Testing Machine (INSTRON 3365)

[0078] Parameters:

[0079] Specimen Size: 50 mm (width) × 150 mm (length), effective test area 50 mm × 100 mm;

[0080] Grip Distance: 100 mm;

[0081] Tensile Speed: 100 mm / min;

[0082] Pre - tension: 1 N;

[0083] Each group tests 5 samples and takes the average value.

[0084] 2. Peel Strength

[0085] Test Standard: GB / T 2792 "Determination of Peel Strength of Adhesives"

[0086] Equipment: Peel Tester (Labthink XLW500C)

[0087] Parameters:

[0088] Specimen Size: 25 mm (width) × 150 mm (length), peel angle 180°;

[0089] Peel Speed: 100 mm / min;

[0090] Pre - peel Length: 50 mm;

[0091] Each group tests 5 samples and takes the average value after excluding outliers.

[0092] 3. Elastic recovery rate

[0093] Test standard: ISO 20932-1 "Textiles - Determination of elastic properties and recovery - Part 1: Strip method"

[0094] Equipment: Cyclic tensile testing machine (MTS C45)

[0095] Parameters:

[0096] Tensile deformation: 50% (relative to the original length);

[0097] Number of cycles: Record the 11th residual deformation after 10 cycles (pre-conditioning);

[0098] Calculation formula: Elastic recovery rate (%) = (L0 - L1) / L0 × 100%, where L0 is the gauge length and L1 is the residual deformation.

[0099] 4. Wash resistance

[0100] Test standard: GB / T 8629 "Textiles - Domestic washing and drying procedures for testing"

[0101] Equipment: Standard washing tester (SDL Atlas M228)

[0102] Parameters:

[0103] Washing procedure: 50 complete washing cycles (water temperature 40°C, standard detergent 5 g / L, drum rotation speed 40 rpm);

[0104] Drying method: Hang to dry;

[0105] Test the breaking stress retention rate after washing.

[0106] 5. Stability in humid and hot environment

[0107] Test method: Simulate the seam deformation under high temperature and high humidity conditions

[0108] Equipment: Thermostatic and humidistatic test chamber (ESPEC PL-3)

[0109] Parameters:

[0110] Environmental conditions: 40°C ± 1°C, relative humidity 95% ± 3%;

[0111] Test time: 24 hours;

[0112] Measuring tool: Laser displacement sensor (KEYENCE LK-G5000), accuracy 0.01 mm; Evaluation index: Seam displacement (linear offset relative to the initial position).

[0113] 6. Dynamic Bending Fatigue Life

[0114] Test Standard: ISO12947-3 "Textiles - Determination of Martindale abrasion resistance of fabrics" Equipment: Martindale abrasion tester (SDLAt l asMart i nda l e)

[0115] Parameters:

[0116] Load pressure: 9 kPa;

[0117] Friction track: Lissajous figure (standard wool felt abrasive);

[0118] Termination condition: Seam breakage or surface damage;

[0119] Record the number of friction cycles.

[0120] III. Experimental Result Data Table

[0121]

[0122]

[0123] IV. Result Analysis and Conclusion

[0124] Breakthrough in mechanical properties:

[0125] The seam breaking strength of Experimental Group 1 (180 N) is 50% higher than that of Control Group 3 (ordinary ultrasonic wave), and the dynamic bending life (8000 times) is 2.3 times that of Control Group 1 (sewing);

[0126] Experimental Group 2 comprehensively surpasses all control groups, and its peel strength reaches 18.3 N / cm (115% higher than that of hot press bonding), meeting the requirements of industrial protective clothing for high peel strength.

[0127] Advantages in environmental adaptability:

[0128] Under humid and hot environment, the seam displacement of Experimental Group 1 (0.25 mm) is only 1 / 4 of that of Control Group 1, and the strength retention rate after 50 washes is ≥ 95%, which is significantly better than that of hot press bonding (65%).

[0129] Verification of technical economy:

[0130] The process speed of the present invention > 15 m / min (traditional sewing ≤ 8 m / min), the energy consumption is reduced by 30% (compared with the hot press process), and at the same time, post-treatment steps such as hemming and overlocking are eliminated, and the single-piece production cost is reduced by 22%.

[0131] Conclusion: The comparative experiments fully prove that the technical route of "ultrasonic pre-splicing + functional reinforcement tape" of the present invention comprehensively surpasses the traditional process in terms of joint strength, durability and environmental adaptability, providing a reliable solution for the joint treatment of high-performance textiles.

[0132] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method for fixing a knitted fabric after ultrasonic splicing with a reinforcing band, characterized in that, It includes the following steps: S1. Prepare materials: Select suitable knitted fabric and reinforcement tape materials. The reinforcement tape is a multi-layer structure, including at least one high-strength fiber layer and one elastic fiber layer, and is coated with hot melt adhesive or binder; S2. Ultrasonic splicing: Seamlessly splice two pieces of knitted fabric along a predetermined splicing line through an ultrasonic welding device; S3. Fix the reinforcement tape: Lay the reinforcement tape along a predetermined path at the splicing point, and heat-treat the reinforcement tape with a hot air blower to make the reinforcement tape initially adhere to the knitted fabric; S4. Flat pressing and fixing: Apply pressure and temperature to the splicing point through a flat pressing machine to further fix the combination of the reinforcement tape and the knitted fabric; S5. Post-treatment: Sort and cut the spliced and fixed fabric to obtain the finished product. This solution achieves a breakthrough in seam performance through a three-level interface strengthening system: The first-level structure (molecular level): Adopt a gradient hot melt adhesive system, including: bottom layer: high-polarity polyurethane adhesive (viscosity 2500 cP@160 °C); Intermediate layer: silane-coupled modified EVA; Surface layer: nano-silica-reinforced TPU The second-level structure (fiber level): The reinforcement tape adopts an orthogonal weaving process: warp: 1000D polyamide 66 filament (breaking strength 8.4 cN / dtex); Weft: 40D spandex filament (breaking elongation 500%); weaving density: 12 warp threads / cm, 8 weft threads / cm The third-level structure (macro level): Design a wavy seam path (amplitude 3 mm, wavelength 8 mm) to improve the stress distribution uniformity by 37% 2. The preparation method of fixing with a reinforcing strip after ultrasonic splicing of a knitted fabric according to claim 1, characterized in that, In the multi-layer structure of the reinforcement tape, the ratio of the high-strength fiber layer to the elastic fiber layer is adjusted according to actual needs to achieve different strength and elasticity combinations.

3. The preparation method of fixing with a reinforcing strip after ultrasonic splicing of a knitted fabric according to claim 1, characterized in that, The ultrasonic splicing parameters include frequency, amplitude and pressure, where the frequency is 20 kHz to 40 kHz, the amplitude is 20 μm to 80 μm, and the pressure is 0.1 MPa to 0.5 MPa. The specific parameters are optimized according to the material and thickness of the knitted fabric.

4. The preparation method of a knitted fabric fixed with a reinforcing strip after ultrasonic splicing according to claim 1, characterized in that, The temperature of the hot air blower is 380 °C - 420 °C, the time is 5 s - 10 s, and it is ensured that the hot air acts evenly on the surface of the reinforcement tape during the heating process.

5. The preparation method of a knitted fabric fixed with a reinforcing strip after ultrasonic splicing according to claim 1, characterized in that, The temperature of the flat pressing machine is 140 - 150 °C, the pressure is 0.25 - 0.45 MPa, and the time is 10 - 15 s. Ensure that the pressure is evenly distributed at the splicing point during the pressing process.

6. The preparation method of fixing with a reinforcing strip after ultrasonic splicing of a knitted fabric according to claim 1, characterized in that, The width of the reinforcement tape is 10 - 15 mm and the thickness is 0.1 mm to 0.3 mm, which can be flexibly adjusted according to the specific requirements of the product.

7. The preparation method of fixing with a reinforcing band after ultrasonic splicing of a knitted fabric according to claim 1, characterized in that, The reinforcement tape is distributed in a straight line or a curve along the splicing line to meet the shape and force requirements of different products.

8. The preparation method of fixing with a reinforcing strip after ultrasonic splicing of a knitted fabric according to claim 1, characterized in that, The knitted fabric is a weft knitted or warp knitted fabric, and the appropriate knitting process and fabric material can be selected according to the performance requirements of the product.

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