Textile hot melt adhesive and preparation method thereof

Abstract

The invention discloses a hot melt adhesive for spinning and a preparation method thereof, and belongs to the technical field of polyurethane hot melt adhesives. The preparation method comprises the following steps: pretreatment of polyether polyol, preparation of tackifying resin, preparation of a polyurethane prepolymer, compounding and post-treatment. According to the invention, through systematic pretreatment of polyether polyol and modification of polyvinyl chloride resin powder by virtue of maleic anhydride grafted polyethylene, the phase separation phenomenon is effectively reduced, so that the peel strength of the adhesive is remarkably improved, and the adhesive has good adhesion in a complex environment simulating daily laundry detergent washing. The detergent can resist chemical erosion of the detergent and physical action of mechanical rubbing, and shows excellent performance stability.

Description

Technical Field

[0001] This invention relates to the field of polyurethane hot melt adhesive technology, specifically to a hot melt adhesive for textiles and its preparation method. Background Technology

[0002] In the textile manufacturing industry, polyurethane hot melt adhesives are an important type of bonding material. With their excellent bonding strength, good temperature resistance, and strong chemical corrosion resistance, they are widely used in the composite processing of various textiles, covering multiple sub-sectors such as apparel fabrics, home textiles, and industrial textiles. As textile technology continues to evolve and market demands for textile quality gradually increase, the industry's performance requirements for polyurethane hot melt adhesives are becoming increasingly refined. They not only need to maintain their core bonding function but also have higher expectations for their stability and operability in practical applications.

[0003] For example, Chinese patent CN118496805B discloses a PUR hot melt adhesive for textiles and its preparation method. Although it has achieved certain results in improving the stringing phenomenon of traditional PUR hot melt adhesives and enhancing washability and flexibility under constant temperature water bath conditions through innovative formula design (such as using a specific ratio of konjac mannan, sorbitol, and amygdalin composite plasticizer), the washability test of this patent only simulates the washing scenario using a pure constant temperature water bath and does not include the laundry detergent that is inevitably used in the actual washing process, resulting in a deviation from the real application environment. The key components in its formula are highly sensitive to the components of laundry detergent. For example, the amygdalin in the composite plasticizer is a natural plant component that is easily decomposed by proteases in laundry detergent, resulting in a loose cross-linking structure inside the adhesive, destroying its dispersion uniformity in the system, and weakening the adhesion. As a result, the peel strength of this patented product decreases much more significantly in actual laundry detergent washing scenarios than in constant temperature water bath scenarios, and it cannot meet the requirement of maintaining stable performance of textiles under high-frequency washing conditions containing laundry detergent.

[0004] Based on this, the present invention designs a hot melt adhesive for textiles and its preparation method to solve the above problems. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, this invention provides a method for preparing a hot melt adhesive for textiles, comprising the following steps: S1. Pretreatment of polyether polyols; The filtered polyether polyol was stirred at 50-70℃; acetic anhydride was added and stirred, and the mixture was allowed to cool naturally to obtain the pretreated polyether polyol. S2. Preparation of tackifying resin; A modifier is obtained by premixing silane coupling agent KH-550, maleic anhydride-grafted polyethylene, and dicumyl peroxide; dried polyvinyl chloride resin powder and the modifier are added to a twin-screw extruder, and the temperature of the extruder is controlled at 140-160℃ in zone 1, 160-180℃ in zone 2, 170-190℃ in zone 3, and 160-170℃ at the die head. After extrusion, the resin is cooled and pulverized by water to obtain a thickening resin. S3. Prepare polyurethane prepolymer; After preheating the reactor, add isocyanate and raise the temperature; add the pretreated polyether polyol in three portions while stirring, and after the addition is complete, react at 80-120℃ and 300-400rpm for 2-4 hours to obtain polyurethane prepolymer. S4. Compound formulation; 64-78 parts of polyurethane prepolymer, 4-7 parts of tributyl citrate plasticizer and 2-5 parts of tackifying resin are stirred and mixed at 70-80℃ to obtain a mixed colloid. S5. Post-processing; The mixed colloids were vacuum degassed to obtain a hot melt adhesive for textiles.

[0006] Furthermore, S1 specifically involves: first filtering the polyether polyol through an 80-mesh filter to remove larger mechanical impurities; then filtering it a second time through a 150-mesh filter to remove fine particles; The filtered polyether polyol was transferred into a stirred tank and stirred at 250-300 rpm. The temperature was raised to 50-70℃ and kept under normal pressure and ventilation for 1-2 hours to remove trace small molecule volatiles adsorbed during polyether storage. Add acetic anhydride at 0.5-0.8% of the mass of the polyether polyol, stir at 220-280 rpm for 30-60 min at 50-60℃, and let it cool naturally to 30-40℃ to obtain the pretreated polyether polyol.

[0007] Furthermore, S2 specifically consists of: weighing 0.3-1.0 parts of silane coupling agent KH-550, 0.5-2.0 parts of maleic anhydride grafted polyethylene, and 0.1-0.5 parts of dicumyl peroxide, adding them to a high-speed mixer, and premixing at 300-500 rpm for 5-10 minutes to obtain the modifier; Place the polyvinyl chloride resin powder in a forced-air drying oven and dry it at 60-80℃ for 2-3 hours to remove surface adsorbed water; The dried polyvinyl chloride resin powder is added to the hopper of a twin-screw extruder, and a premixed modifier is added through the side feed port. The temperature of the extruder is controlled at 140-160℃ in zone 1, 160-180℃ in zone 2, 170-190℃ in zone 3, 160-170℃ at the die head, and 180-220 rpm at the screw speed. After 40-55 minutes, the extruded modified resin is cooled by water and then sent to a pulverizer to be pulverized to below 120 mesh to obtain the tackifying resin.

[0008] Furthermore, in S2, the mass ratio of the polyvinyl chloride resin powder to the modifier is 22-28:1.3-2.8.

[0009] Furthermore, S3 specifically involves: preheating the reactor to 50-56℃, adding isocyanate, and raising the temperature to 60-75℃; adding the pretreated polyether polyol in three equal parts while stirring at 200-300 rpm, with each addition occurring at 5-10 min intervals; and reacting at 80-120℃ and 300-400 rpm for 2-4 h after the addition is complete to obtain the polyurethane prepolymer.

[0010] Furthermore, in S3, the mass ratio of the isocyanate to the pretreated polyether polyol is 15-35:26-57.

[0011] Furthermore, in S3, the isocyanate is selected from one or more of HDI, HMDI, or LDI.

[0012] Furthermore, S4 specifically involves mixing 64-78 parts of polyurethane prepolymer, 4-7 parts of tributyl citrate plasticizer, and 2-5 parts of tackifying resin at 70-80℃ and 250-300rpm for 30-45 minutes to obtain a mixed colloid.

[0013] Furthermore, S5 specifically involves degassing the mixed colloid under a vacuum of -98 kPa to -95 kPa for 20-30 minutes to obtain a hot melt adhesive for textiles.

[0014] A hot melt adhesive for textiles prepared according to the preparation method of the hot melt adhesive for textiles.

[0015] Compared with the prior art, the beneficial effects of this invention are as follows: 1. This invention, through systematic pretreatment of polyether polyols, lays a stable foundation for the crosslinking reaction of the adhesive system, better maintaining the core adhesive function of polyurethane hot melt adhesives and providing reliable adhesive support for various textile composite processing. By modifying polyvinyl chloride resin powder with maleic anhydride-grafted polyethylene, phase separation is effectively reduced, significantly improving the peel strength of the adhesive and enabling a stronger interfacial bond during fabric bonding, thus adapting to practical applications in textile composite processing.

[0016] 2. The series of targeted improvements in this invention enable the adhesive to resist the chemical erosion of detergent and the physical action of mechanical rubbing in the complex environment of simulating daily laundry detergent washing, exhibiting excellent performance stability, effectively inhibiting the attenuation of adhesive layer strength and structural damage, making up for the shortcomings of the adhesive in the actual washing scenario containing laundry detergent in the prior art, and meeting the stringent requirements for the stability of adhesive performance under high-frequency actual washing conditions of textiles. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] Example 1: This example provides a method for preparing a hot melt adhesive for textiles, comprising the following steps: S1. Pretreatment of polyether polyols; The polyether polyol (purchased from Nantong Jienuo Chemical Co., Ltd., CAS No. 25322-69-4) was first filtered through an 80-mesh filter to remove larger mechanical impurities; then it was filtered a second time through a 150-mesh filter to remove fine particles (such as residual catalyst particles from the raw material synthesis). The filtered polyether polyol was transferred into a stirred tank and stirred at 300 rpm. The temperature was raised to 70°C and kept under normal pressure and ventilation (natural ventilation through the exhaust port on the top of the tank) for 2 hours to remove trace small molecule volatiles adsorbed during the storage of the polyether. Add acetic anhydride at 0.8% of the mass of the polyether polyol, stir at 280 rpm for 60 min at 60 °C, and cool naturally to 40 °C to obtain the pretreated polyether polyol. S2. Preparation of tackifying resin; Weigh out 1.0 part of silane coupling agent KH-550, 2.0 parts of maleic anhydride grafted polyethylene (purchased from Dongguan Shenghao Plastic Raw Materials Co., Ltd., CAS No. 9999), and 0.5 parts of dicumyl peroxide in proportion, add them to a high-speed mixer, and premix at 500 rpm for 10 min to obtain the modifier. The polyvinyl chloride resin powder was placed in a forced-air drying oven and dried at 80°C for 3 hours to remove surface adsorbed water. The dried polyvinyl chloride resin powder was added to the hopper of a twin-screw extruder, and a premixed modifier was added through the side feed port. The mass ratio of polyvinyl chloride resin powder to modifier was 28:2.8. The temperature of the extruder was controlled at 160°C in zone 1, 180°C in zone 2, 190°C in zone 3, 170°C at the die head, and 220 rpm at the screw speed. After 55 minutes, the extruded modified resin was cooled by water and then sent to a pulverizer to be pulverized to below 120 mesh to obtain the tackifying resin. The polyvinyl chloride resin powder was purchased from Wuhan Xindongyi Chemical Co., Ltd., and the model is Beiyuan PVC SG-3. S3. Prepare polyurethane prepolymer; The reactor was preheated to 56°C, isocyanate was added, and the temperature was raised to 75°C. The pretreated polyether polyol was added in three equal parts while stirring at 300 rpm, with a 10-minute interval between each addition. After the addition was complete, the reaction was carried out at 120°C and 400 rpm for 4 hours to obtain the polyurethane prepolymer. The mass ratio of the isocyanate to the pretreated polyether polyol is 35:57. The isocyanate used is HDI; S4. Compound formulation; 78 parts of polyurethane prepolymer, 7 parts of tributyl citrate plasticizer and 5 parts of tackifying resin were stirred and mixed at 80°C and 300 rpm for 45 min to obtain a mixed colloid. S5. Post-processing; The mixed colloid was degassed under a vacuum of -98 kPa for 30 min to obtain a hot melt adhesive for textiles.

[0019] Example 2: This example provides a method for preparing a hot melt adhesive for textiles, including the following steps: S1. Pretreatment of polyether polyols; The polyether polyol is first filtered through an 80-mesh filter to remove larger mechanical impurities; then it is filtered a second time through a 150-mesh filter to remove fine particles (such as residual catalyst particles from the raw material synthesis). The filtered polyether polyol was transferred into a stirred tank and stirred at 250 rpm. The temperature was raised to 50°C and kept under normal pressure and ventilation (natural ventilation through the exhaust port on the top of the tank) for 1 hour to remove trace small molecule volatiles adsorbed during the storage of the polyether. Add acetic anhydride at 0.5% of the mass of the polyether polyol, stir at 220 rpm for 30 min at 50°C, and cool naturally to 30°C to obtain the pretreated polyether polyol. S2. Preparation of tackifying resin; Weigh out 0.3 parts of silane coupling agent KH-550, 0.5 parts of maleic anhydride grafted polyethylene, and 0.1 parts of dicumyl peroxide according to the proportion, add them to a high-speed mixer, and premix at 300 rpm for 5 min to obtain the modifier. The polyvinyl chloride resin powder was placed in a forced-air drying oven and dried at 60°C for 2 hours to remove surface adsorbed water. The dried polyvinyl chloride resin powder was added to the hopper of a twin-screw extruder, and a premixed modifier was added through the side feed port. The mass ratio of polyvinyl chloride resin powder to modifier was 22:1.3. The temperature of the extruder was controlled at 140°C in zone 1, 160°C in zone 2, 170°C in zone 3, 160°C at the die head, and 180 rpm at the screw speed. After 40 minutes, the extruded modified resin was cooled by water and then sent to a pulverizer to be pulverized to below 120 mesh to obtain the tackifying resin. S3. Prepare polyurethane prepolymer; Preheat the reactor to 50°C, add isocyanate, and raise the temperature to 60°C; add the pretreated polyether polyol in three equal parts while stirring at 200 rpm, with a 5-minute interval between each addition, and react at 80°C and 300 rpm for 2 hours to obtain polyurethane prepolymer. The mass ratio of the isocyanate to the pretreated polyether polyol is 15:26. The isocyanate is selected from one or more LDIs; S4. Compound formulation; 64 parts of polyurethane prepolymer, 4 parts of tributyl citrate plasticizer and 2 parts of tackifying resin were stirred and mixed at 70°C and 250 rpm for 30 min to obtain a mixed colloid. S5. Post-processing; The mixed colloid was degassed under a vacuum of -95 kPa for 20 min to obtain a hot melt adhesive for textiles.

[0020] Example 3: This example provides a method for preparing a hot melt adhesive for textiles, including the following steps: S1. Pretreatment of polyether polyols; The polyether polyol is first filtered through an 80-mesh filter to remove larger mechanical impurities; then it is filtered a second time through a 150-mesh filter to remove fine particles (such as residual catalyst particles from the raw material synthesis). The filtered polyether polyol was transferred into a stirred tank and stirred at 260 rpm. The temperature was raised to 67°C and kept under normal pressure and ventilation (natural ventilation through the exhaust port on the top of the tank) for 2 hours to remove trace small molecule volatiles adsorbed during the storage of the polyether. Add acetic anhydride at 0.7% of the mass of the polyether polyol, stir at 260 rpm for 50 min at 54 °C, and cool naturally to 38 °C to obtain the pretreated polyether polyol. S2. Preparation of tackifying resin; Weigh 0.7 parts of silane coupling agent KH-550, 1.3 parts of maleic anhydride grafted polyethylene, and 0.2 parts of diisopropylbenzene peroxide according to the proportion, add them to a high-speed mixer, and premix for 8 min at 400 rpm to obtain a modifier; Place the polyvinyl chloride resin powder in a forced-air drying oven and dry it at 77 °C for 2 h to remove the surface adsorbed water; Add the dried polyvinyl chloride resin powder to the hopper of a twin-screw extruder, and at the same time add the premixed modifier through the side feeder. The mass ratio of the polyvinyl chloride resin powder to the modifier is 25:1.9. Control the temperature of the first zone of the extruder at 148 °C, the second zone at 172 °C, the third zone at 185 °C, the head temperature at 167 °C, the screw speed at 205 rpm. After 52 min, the extruded modified resin is cooled by water cooling and then sent to a crusher to be crushed into particles below 120 mesh to obtain the tackifying resin; S3. Preparation of polyurethane prepolymer; Preheat the reactor to 52 °C, add isocyanate, and raise the temperature to 70 °C; add the pretreated polyether polyol in three equal parts, while adding, stir at 240 rpm, with an interval of 8 min each time. After adding, react at 110 °C and 360 rpm for 3 h to obtain the polyurethane prepolymer; The mass ratio of the isocyanate to the pretreated polyether polyol is 22:39; The isocyanate selected is HMD; S4. Compound; Mix 73 parts of polyurethane prepolymer, 5 parts of tributyl citrate plasticizer and 3 parts of tackifying resin at 73 °C and 275 rpm for 41 min to obtain a mixed colloid; S5. Post-treatment; Debubbling the mixed colloid under -96 kPa vacuum for 24 min to obtain the hot-melt adhesive for textiles.

[0021] Example 4: This example provides a preparation method of a hot-melt adhesive for textiles, including the following steps: S1. Pretreatment of polyether polyol; First, preliminarily filter the polyether polyol through an 80-mesh filter screen to remove larger-sized mechanical impurities; then, perform secondary filtration through a 150-mesh filter screen to remove fine particles (such as catalyst particles remaining from raw material synthesis); Transfer the filtered polyether polyol into a stirring kettle, stir at 290 rpm, raise the temperature to 55 °C, and maintain the normal pressure ventilation state (naturally ventilate through the exhaust port at the top of the kettle) for 1.5 h to remove trace small molecule volatiles adsorbed during the storage of the polyether; Add acetic anhydride at 0.6% of the mass of the polyether polyol, stir at 270 rpm for 40 min at 52 °C, and cool naturally to 37 °C to obtain the pretreated polyether polyol. S2. Preparation of tackifying resin; Weigh out 0.9 parts of silane coupling agent KH-550, 1.7 parts of maleic anhydride grafted polyethylene, and 0.4 parts of dicumyl peroxide according to the proportion, add them to a high-speed mixer, and premix at 410 rpm for 8 min to obtain the modifier. The polyvinyl chloride resin powder was placed in a forced-air drying oven and dried at 72°C for 2.5 hours to remove surface adsorbed water. The dried polyvinyl chloride resin powder was added to the hopper of a twin-screw extruder, and a premixed modifier was added through the side feed port. The mass ratio of polyvinyl chloride resin powder to modifier was 26:2.2. The temperature of the extruder was controlled at 152°C in zone 1, 169°C in zone 2, 174°C in zone 3, 166°C at the die head, and 205 rpm at the screw speed. After 52 minutes, the extruded modified resin was cooled by water and then sent to a pulverizer to be pulverized to below 120 mesh to obtain the tackifying resin. S3. Prepare polyurethane prepolymer; The reactor was preheated to 55°C, isocyanate was added, and the temperature was raised to 72°C. The pretreated polyether polyol was added in three equal parts while stirring at 240 rpm, with an 8-minute interval between each addition. After the addition was complete, the reaction was carried out at 115°C and 380 rpm for 3.5 hours to obtain the polyurethane prepolymer. The mass ratio of the isocyanate to the pretreated polyether polyol is 30:54. The isocyanate is selected from a mixture of HDI and HMDI in a mass ratio of 1:1; S4. Compound formulation; 69 parts of polyurethane prepolymer, 6 parts of tributyl citrate plasticizer and 4 parts of tackifying resin were stirred and mixed at 159°C and 282 rpm for 38 min to obtain a mixed colloid. S5. Post-processing; The mixed colloid was degassed under a vacuum of -97 kPa for 28 min to obtain a hot melt adhesive for textiles.

[0022] Comparative Example 1: The difference between this comparative example and Example 4 is that maleic anhydride was used instead of acetic anhydride when pretreating the polyether polyol.

[0023] Comparative Example 2: The difference between this comparative example and Example 4 is that 1.5 parts of silane coupling agent KH-550, 0.1 parts of maleic anhydride-grafted polyethylene, and 1.4 parts of dicumyl peroxide were added when preparing the tackifying resin.

[0024] Comparative Example 3: The difference between this comparative example and Example 4 is that the polyvinyl chloride resin powder was replaced with chlorinated polypropylene resin powder when preparing the tackifying resin.

[0025] Comparative Example 4: The difference between this comparative example and Example 4 is that the polyether polyol was not pretreated, and the polyvinyl chloride resin powder was replaced with chlorinated polypropylene resin powder.

[0026] Comparative example: Example 3 of Chinese patent CN118496805B was selected.

[0027] Experimental Example 1: Determining the machine wash resistance of the prepared hot melt adhesive for textiles to laundry detergent; Commonly used textile materials, such as pure cotton fabric (21 count, 200 g / m²) and polyester fabric (75D / 36F, 150 g / m²), were selected and cut into 150 mm × 50 mm samples, with 10 pieces of each material in each group. After wiping the oil stains on the substrate surface with anhydrous ethanol, the prepared textile hot melt adhesive was melted at 180°C and evenly coated onto the surface of the pure cotton fabric using a coater, with the amount of adhesive controlled at 20 g / m². The polyester fabric was immediately bonded to the coated surface and hot-pressed for 20 seconds under a pressure of 0.2 MPa (hot-pressing temperature 120°C) to prepare a cotton / adhesive / polyester composite sample. The composite sample was then left to stand for 48 hours at 25°C and 50% relative humidity to ensure complete curing of the adhesive layer before use.

[0028] Select a commercially available neutral laundry detergent (main ingredients: 12% surfactant, 1% chelating agent, 0.5% protease), prepare a 1.0wt% detergent solution according to the daily washing ratio, stir until completely dissolved, and set aside.

[0029] Place the cotton / rubber / polyester composite sample into a washing machine, add the prepared washing solution, and wash at 40℃ for 40 minutes at a speed of 800 r / min. After washing, remove the sample and hang it in an environment of 25℃ and 50% relative humidity to air dry naturally, avoiding direct sunlight. The drying time is 24 hours. Repeat the test 120 times.

[0030] The 180° peel strength σ0, σ1 and strength retention rate η1 before and after washing were determined according to GB / T2791-1995 "Adhesives T Peel Strength Test Method" (η = strength after washing / strength before washing × 100%).

[0031] Experimental Example 2: Determining the resistance of the prepared hot melt adhesive for textiles to hand washing with laundry detergent; The cotton / rubber / polyester composite sample was fully immersed in the washing solution for 20 minutes. A reciprocating rubbing color fastness tester was used, simulating the rubbing action of a hand through reciprocating motion. The rubbing intensity was controlled by a pressure sensor to match the mechanical characteristics of hand washing. The adjustment parameters are as follows: Kneading pressure: 10N (simulating the pressure of an adult's palm); Reciprocating frequency: 40 times / minute (matching the speed of daily hand kneading); Reciprocating stroke: 80mm (covering the effective length of the sample to avoid edge effects); Contact medium: A 5mm thick elastic rubber pad is used (to simulate the softness of a hand and avoid rigid friction damage to the sample). After running continuously for 8 minutes, dehydrate at 500 r / min for 2 minutes, hang in an environment of 25℃ and 50% relative humidity to air dry naturally, avoiding direct sunlight, and let it dry for 24 hours. Repeat the test 120 times.

[0032] The 180° peel strength σ2 and strength retention rate η2 after washing were determined in accordance with GB / T2791-1995 "Adhesives T Peel Strength Test Method".

[0033] The results are shown in the table below: As shown in the table above, the present invention, through the pretreatment process of polyether polyol (including multi-stage filtration to remove impurities, heating to remove volatiles and acetic anhydride modification), can reduce the interference of impurities on subsequent reactions, while optimizing the reactivity of polyether polyol, so that when it reacts with isocyanate to form polyurethane prepolymer, it forms a more uniform and stable polymer structure, laying a solid foundation for the overall performance of the adhesive and reducing the risk of strength reduction due to structural inhomogeneity during subsequent washing.

[0034] Furthermore, this invention uses a modifier composed of maleic anhydride-grafted polyethylene, silane coupling agent, and dicumyl peroxide to modify polyvinyl chloride resin powder. This modifier improves the interfacial bonding between polyvinyl chloride and the polyurethane matrix, reduces phase separation problems that may occur due to poor compatibility, allows the tackifying resin to better integrate into the adhesive system, and enhances the bonding force within the adhesive layer. As a result, it can maintain good structural stability even under the chemical action of laundry detergent and the mechanical rubbing during the washing process.

[0035] As shown in the table above, when key technical aspects are adjusted, the wash resistance of the adhesive fluctuates accordingly. Replacing the reagents used in the polyether polyol pretreatment will disrupt the original optimization effect on the reactivity and purity of the polyether, leading to a decrease in the structural stability of the polyurethane prepolymer. Changing the component ratio of the tackifying resin modifier will destroy the modifier's modification effect on polyvinyl chloride, affecting its interfacial compatibility with the polyurethane matrix. Replacing the type of base resin in the tackifying resin will worsen the compatibility between the new resin and the polyurethane matrix, making it difficult to form a stable bond. If the polyether pretreatment is omitted and the base resin is replaced, the above problems are compounded, further weakening the adhesive's wash resistance.

[0036] In contrast, the existing technical solutions used in the comparative examples do not involve the targeted pretreatment of polyether polyols and the modification design of polyvinyl chloride resin powder as described in this invention. The internal structural stability and interfacial bonding of the adhesive system are relatively weak. When faced with the chemical erosion of laundry detergent and the mechanical action of washing, the adhesive layer is prone to structural loosening and decreased bonding strength. Therefore, the strength retention rate is significantly lower than that of the embodiments of this invention.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a textile hot-melt adhesive, characterized by, Comprising the following steps: S1. Polyether polyol pretreatment; Stir the filtered polyether polyol at 50-70℃; add acetic anhydride and stir, and after natural cooling, obtain pretreated polyether polyol; S2. Preparation of tackifying resin; Pre-mix silane coupling agent KH-550, maleic anhydride grafted polyethylene and dicumyl peroxide to obtain a modifier; add dry polyvinyl chloride resin powder and the modifier to a twin-screw extruder, control the temperature of the first zone of the extruder to be 140-160℃, the temperature of the second zone to be 160-180℃, and the temperature of the third zone to be 170-190℃, the temperature of the die head to be 160-170℃, and after extrusion, crush after water cooling to obtain tackifying resin; S3. Preparation of polyurethane prepolymer; After preheating the reactor, add isocyanate and heat; add the pretreated polyether polyol in three portions while stirring, and after addition, react at 80-120℃ and 300-400rpm for 2-4h to obtain polyurethane prepolymer; S4. Compounding; Stir and mix 64-78 parts of polyurethane prepolymer, 4-7 parts of tributyl citrate plasticizer and 2-5 parts of tackifying resin at 70-80℃ to obtain mixed glue; S5. Post-treatment; Vacuum degassing treatment of the mixed glue to obtain a hot melt adhesive for textiles.

2. The method of preparing a textile hot melt adhesive according to claim 1, characterized in that, S1 is specifically: first filter the polyether polyol through an 80-mesh filter screen to remove mechanical impurities with larger particle sizes; then filter again through a 150-mesh filter screen to remove fine particles; Transfer the filtered polyether polyol into a stirred tank, stir at 250-300rpm, heat to 50-70℃, maintain normal pressure and ventilation for 1-2h to remove trace amounts of volatile small molecules adsorbed during polyether storage; Add acetic anhydride accounting for 0.5-0.8% of the mass of the polyether polyol, stir at 220-280rpm for 30-60min at 50-60℃, and naturally cool to 30-40℃ to obtain pretreated polyether polyol.

3. The method for preparing the hot melt adhesive for textiles according to claim 1, characterized in that, S2 is specifically: weigh 0.3-1.0 parts of silane coupling agent KH-550, 0.5-2.0 parts of maleic anhydride grafted polyethylene and 0.1-0.5 parts of dicumyl peroxide, add to a high-speed mixer, and pre-mix at 300-500rpm for 5-10min to obtain a modifier; Dry the polyvinyl chloride resin powder in a forced air drying oven at 60-80℃ for 2-3h to remove surface adsorbed water; Add the dry polyvinyl chloride resin powder to the hopper of a twin-screw extruder, and simultaneously add the pre-mixed modifier through the side feeding port, control the temperature of the first zone of the extruder to be 140-160℃, the temperature of the second zone to be 160-180℃, and the temperature of the third zone to be 170-190℃, the temperature of the die head to be 160-170℃, and the screw rotation speed to be 180-220rpm, and after 40-55min, crush the modified resin after water cooling to obtain tackifying resin with a particle size of 120 mesh or less.

4. The method of preparing a textile hot melt adhesive according to claim 1, characterized in that, In S2, the mass ratio of the polyvinyl chloride resin powder to the modifier is 22-28:1.3-2.

8.

5. The method of preparing a textile hot melt adhesive according to claim 1, wherein, S3 is specifically: the reactor is preheated to 50-56℃, the isocyanate is added, and the temperature is raised to 60-75℃; the pretreated polyether polyol is added in three equal portions, stirring at 200-300rpm during addition, with an interval of 5-10min each time, after addition, reaction at 80-120℃, 300-400rpm for 2-4h, to obtain a polyurethane prepolymer.

6. The method of preparing a textile hot melt adhesive according to claim 1, wherein, In S3, the mass ratio of the isocyanate and the pretreated polyether polyol is 15-35:26-57.

7. The method for preparing the hot melt adhesive for textiles according to claim 1, characterized in that, In S3, the isocyanate is selected from one or more of HDI, HMDI or LDI.

8. The method of preparing a textile hot melt adhesive according to claim 1, wherein, S4 is specifically: 64-78 parts of the polyurethane prepolymer, 4-7 parts of tributyl citrate plasticizer and 2-5 parts of tackifying resin are mixed at 70-80℃, 250-300rpm for 30-45min to obtain a mixed glue.

9. The method for preparing the hot melt adhesive for textiles according to claim 1, characterized in that, S5 is specifically: the mixed glue is defoamed under a vacuum of-98kPa to-95kPa for 20-30min to obtain the textile hot melt adhesive.

10. A textile hot melt adhesive prepared by the preparation method of any one of claims 1-9.

Images