Preparation method of PLA composite fabric

Abstract

The application discloses a preparation method of a PLA composite fabric, which comprises the following steps: applying a flame-retardant layer on the surface of a PLA base fabric, and then combining the flame-retardant layer with a functional film to prepare the fabric with the functions of flame retardation, waterproof and moisture permeation. 1) applying a flame-retardant coating agent on the surface of the PLA base fabric: slowly adding phosphorus-containing quaternary ammonium salt organosiloxane sol into polyurethane emulsion, uniformly stirring, and preparing the flame-retardant coating agent; and coating the flame-retardant coating agent on the surface (single surface) of the PLA base fabric. 2) combining the base fabric with the functional film: ① gluing: coating polyurethane hot melt adhesive on the surface of the base fabric and the functional film; ② film laminating: laminating the fabric and the film together, then moving to a pressing and ironing machine, setting the hot pressing temperature and the hot pressing time, and then pressing and ironing after the temperature reaches the set temperature, so as to complete the hot pressing film laminating and prepare the PLA composite fabric. The phosphorus-containing quaternary ammonium salt organosiloxane sol is a high-efficiency halogen-free flame retardant which integrates phosphorus, nitrogen and silicon elements, and has good flame-retardant synergistic effect.

Description

Technical Field

[0001] This invention relates to a method for preparing PLA composite fabric, belonging to the field of functional textile fabrics. Background Technology

[0002] PLA (polylactic acid) is a fully biodegradable polymer with numerous advantages, including safety, environmental friendliness, and strong mechanical properties, making it widely used in the textile and apparel industry. However, PLA is highly flammable, with a LOI value of only about 19%, and its combustion process easily produces flammable droplets, severely limiting its applications. To promote the application of PLA fabrics and improve their fire safety, it is essential to enhance their flame-retardant properties. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing PLA composite fabric, which involves first applying a flame-retardant layer to the surface of a PLA substrate fabric, and then laminating it with a functional film to produce a fabric with flame-retardant and waterproof functions.

[0004] To achieve the above objectives, the present invention adopts the following technical solution.

[0005] A method for preparing PLA composite fabric includes the following steps:

[0006] A flame-retardant coating is applied to the surface of the PLA substrate fabric.

[0007] PLA composite fabric is made by combining the base material with a functional film.

[0008] By weight, the flame retardant coating agent consists of 28 parts phosphorus-containing quaternary ammonium salt organosiloxane sol, 70 parts polyurethane emulsion, and 0.1-2 parts thickener.

[0009] The phosphorus-containing quaternary ammonium salt organosiloxane sol is prepared by adding 40 parts of tetraethyl orthosilicate (TEOS), 2 parts of acetic acid, 10 parts of deionized water and 240 parts of ethylene glycol monomethyl ether into a container and stirring at room temperature for 30 minutes for pre-hydrolysis; then adding 18 parts of phosphorus-containing quaternary ammonium salt organosiloxane and 2 parts of 3-glycidyl etheroxypropyltrimethoxysilane (KH560) into the above container and stirring at room temperature for 12 hours to obtain the phosphorus-containing quaternary ammonium salt organosiloxane sol.

[0010] The phosphorus-containing quaternary ammonium salt organosiloxane is prepared by the following method:

[0011] 17.3g of diethyl chlorophosphate and 50mL of tetrahydrofuran were added to reactor S1, and nitrogen gas was introduced for protection. Then, 9g of N,N-dimethylethanolamine and 3g of triethylamine were added and the mixture was stirred in an ice-water bath for 4 hours. After the reaction was complete, the organic solvent tetrahydrofuran was removed by vacuum distillation and filtered to obtain (triethyl phosphate)N,N-dimethylamine.

[0012] In a reactor equipped with a stirrer, condenser, and thermometer, S2 was added to 22.5 g of (triethyl phosphate) N,N-dimethylamine, 24 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and 140 g of isopropanol. The mixture was stirred and stirred until homogeneous, and then refluxed at 70 °C until the reactants became transparent. The reaction was then carried out for another 2 hours. The isopropanol was then removed under 0.01 MPa to obtain a viscous liquid, which is a phosphorus-containing quaternary ammonium salt organosiloxane.

[0013] The functional film is a TPU film (thermoplastic polyurethane film) with a thickness of 0.012-0.015 mm.

[0014] The specific steps for laminating the substrate fabric with the functional film are as follows:

[0015] ① Applying adhesive: First, apply hot melt adhesive to the surface of the substrate fabric and the functional film.

[0016] ②Lamination: The fabric and film are flatly stacked together, then transferred to a heat press machine. The heat pressing time and temperature are set, and after the temperature is reached, the heat press is performed to complete the heat pressing and lamination, thus producing PLA composite fabric.

[0017] The hot melt adhesive is a polyurethane hot melt adhesive, with a coating amount of 30-40 g / m². 2 .

[0018] The present invention discloses a method for preparing PLA composite fabric, which involves first applying a flame-retardant layer to the surface of a PLA substrate fabric, and then laminating it with a functional film to produce a fabric with flame-retardant, waterproof and breathable functions.

[0019] Phosphorus-containing quaternary ammonium salt organosiloxane sol is a highly efficient halogen-free flame retardant that integrates phosphorus, nitrogen, and silicon elements. It has a good flame retardant synergistic effect. Through the separate crosslinking of covalent bonds (-Si-OC- bonds) and epoxy groups, the coating has good mechanical properties, a smooth surface, good transparency, and excellent durability and strength.

[0020] The polyurethane undergoes a cross-linking reaction with the sol, enhancing the toughness and durability of the coating film. Detailed Implementation

[0021] The technical solution of the present invention will be described in detail below through specific embodiments.

[0022] This invention discloses a method for preparing PLA composite fabric, comprising the following steps:

[0023] A flame-retardant coating is applied to the surface of the PLA substrate fabric.

[0024] PLA composite fabric is made by combining the base material with a functional film.

[0025] The PLA substrate fabric is coated with a flame-retardant coating agent on the surface and laminated with a film on the back.

[0026] The flame-retardant coating agent is composed of a phosphorus-containing quaternary ammonium salt organosiloxane sol, a polyurethane emulsion, and a thickener. By weight, it comprises 28 parts phosphorus-containing quaternary ammonium salt organosiloxane sol, 70 parts polyurethane emulsion, and 0.1-2 parts thickener. An appropriate amount of thickener is used to adjust the viscosity of the flame-retardant coating agent system to 6000-8000 mPa·s. The thickener is nonionic, such as nonionic thickener YC-100 (Anhui Yuanchen New Material Technology Co., Ltd.).

[0027] The functional film is a commercially available TPU film (thermoplastic polyurethane film) with a thickness of 0.012-0.015mm, which can give the fabric good waterproof performance.

[0028] The phosphorus-containing quaternary ammonium salt organosiloxane sol is prepared by adding 40 parts of tetraethyl orthosilicate (TEOS), 2 parts of acetic acid, 10 parts of deionized water and 240 parts of ethylene glycol monomethyl ether into a container and stirring at room temperature for 30 minutes for pre-hydrolysis; then adding 18 parts of phosphorus-containing quaternary ammonium salt organosiloxane and 2 parts of 3-glycidyl etheroxypropyltrimethoxysilane (KH560) into the above container and stirring at room temperature for 12 hours to obtain the phosphorus-containing quaternary ammonium salt organosiloxane sol.

[0029] The phosphorus-containing quaternary ammonium salt organosiloxane is prepared by the following method:

[0030] 17.3g of diethyl chlorophosphate and 50mL of tetrahydrofuran were added to reactor S1, and nitrogen gas was introduced for protection. Then, 9g of N,N-dimethylethanolamine and 3g of triethylamine were added and the mixture was stirred in an ice-water bath for 4 hours. After the reaction was complete, the organic solvent tetrahydrofuran was removed by vacuum distillation and filtered to obtain (triethyl phosphate)N,N-dimethylamine.

[0031] In a reactor equipped with a stirrer, condenser, and thermometer, S2 was added to 22.5 g of (triethyl phosphate) N,N-dimethylamine, 24 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and 140 g of isopropanol. The mixture was stirred and stirred until homogeneous, and then refluxed at 70 °C until the reactants became transparent. The reaction was then carried out for another 2 hours. The isopropanol was then removed under 0.01 MPa to obtain a viscous liquid, which is a phosphorus-containing quaternary ammonium salt organosiloxane.

[0032] The reaction formula for preparing phosphorus-containing quaternary ammonium salt organosiloxanes is as follows:

[0033]

[0034] The polyurethane emulsion is prepared by the following method:

[0035] Polypropylene glycol (molecular weight 2000), isophorone diisocyanate, and dibutyltin dilaurate were added to a reactor equipped with a stirrer, condenser, and thermometer, and reacted at 90°C for 2 hours. Dimethylolpropionic acid and N,N-di(2-hydroxyethyl)-3-methylsilane (as shown in Formula 3) were added, and the reaction was carried out for 1 hour. Then methyl ethyl ketone oxime was added, and the reaction was carried out for 2 hours. The mixture was cooled to room temperature, neutralized with triethylamine, and then stirred at high speed for 30 minutes with deionized water to obtain a capped polyurethane emulsion.

[0036] The molar ratio of isophorone diisocyanate to polypropylene glycol is 1.8-1.5:1, the molar ratio of N,N-bis(2-hydroxyethyl)-3-methylsilane to isophorone diisocyanate is 0.1:1, and dimethylolpropionic acid accounts for 5-8% of the total mass of isophorone diisocyanate and polypropylene glycol.

[0037]

[0038] The specific steps for laminating the substrate fabric with the functional film are as follows:

[0039] ① Applying adhesive: First, apply hot melt adhesive to the surface of the substrate fabric and the functional film.

[0040] ②Lamination: The fabric and film are flatly stacked together, then transferred to a heat press machine. The heat pressing time and temperature are set, and after the temperature is reached, the heat press is performed to complete the heat pressing and lamination, thus producing PLA composite fabric.

[0041] The hot melt adhesive mentioned is a commercially available polyurethane hot melt adhesive. The coating amount of the hot melt adhesive on the surface of the fabric or functional film is 30-40 g / m². 2 .

[0042] The PLA base fabric used in the example has the following characteristics: warp and weft threads: PLA and cotton fiber blended yarn; composition: 50% PLA + 50% cotton; warp and weft density: 450×240.

[0043] Pretreatment of substrate fabric before scouring: The substrate fabric is immersed in the pretreatment solution → heated to 100℃ and kept warm for 30 minutes → cooled and washed with water; The pretreatment solution contains 4g / L soda ash, 2g / L scouring agent, 2g / L chelating dispersant, and the remainder is water, with a bath ratio of 1:8.

[0044] The refining agents and chelating dispersants involved in the pre-refining process are all commercially available conventional products.

[0045] Example 1:

[0046] The preparation method of PLA composite fabric includes the following steps:

[0047] 1) Applying a flame-retardant coating to the surface of PLA substrate fabric: Slowly add phosphorus-containing quaternary ammonium salt organosiloxane sol to polyurethane emulsion, stir evenly, ultrasonically disperse for 30 minutes, and then adjust the viscosity to 6000-8000 mPa·s with nonionic thickener YC-100 to obtain the flame-retardant coating; apply 100-120 g / m² of the flame-retardant coating to the surface of PLA substrate fabric (single-sided). 2 Dry at 100℃ for 2 minutes, then bake at 160℃ for 30 seconds; by weight, the flame retardant coating agent contains 28 parts of phosphorus quaternary ammonium salt organosiloxane sol, 70 parts of polyurethane emulsion, and 0.1-2 parts of thickener.

[0048] 2) Composite of substrate fabric and functional film:

[0049] ① Adhesive application: First, apply polyurethane hot melt adhesive to the surface of the substrate and functional film. The amount of hot melt adhesive applied is 30-40g / m². 2 ;

[0050] ②Lamination: The fabric and film are flatly stacked together and then transferred to a heat press machine. The heat pressing temperature is set to 105℃ and the heat pressing time is 30s. After the temperature is reached, the heat is pressed with a winding pressure of 3kg and a bonding speed of 10m / min to complete the heat pressing and lamination, thus producing PLA composite fabric.

[0051] The PLA composite fabric prepared by the method in the examples was tested for flame retardancy, water resistance and other properties.

[0052] The flame retardant properties of PLA composite fabric are as follows: afterflame time 0s, smoldering time 0s, and damage length 8.5cm. The flame retardant performance test is conducted in accordance with GB / T 5455-2014 "Determination of vertical damage length, smoldering and afterflame time of textiles".

[0053] Waterproof performance of PLA composite fabric:

[0054] Hydrostatic pressure resistance: 1387 mmH2O, test method refers to "GB / T4744-2013 Test and evaluation of waterproof performance of textiles - hydrostatic pressure method".

[0055] Water repellency rating: 4-5. The test method is in accordance with GB / T 4745-2012 "Test and evaluation of waterproof performance of textiles - water repellency method".

Claims

1. A method for preparing a PLA composite fabric, comprising the following steps: A flame-retardant coating is applied to the surface of the PLA substrate fabric. PLA composite fabric is made by combining PLA substrate fabric with functional film. The flame retardant coating agent, by weight, consists of 28 parts phosphorus-containing quaternary ammonium salt organosiloxane sol, 70 parts polyurethane emulsion, and 0.1-2 parts thickener; The specific preparation method of the phosphorus-containing quaternary ammonium salt organosiloxane sol is as follows: 40 parts of tetraethyl orthosilicate, 2 parts of acetic acid, 10 parts of deionized water and 240 parts of ethylene glycol monomethyl ether are added to a container and stirred at room temperature for 30 minutes for pre-hydrolysis; then 18 parts of phosphorus-containing quaternary ammonium salt organosiloxane and 2 parts of 3-glycidyl etheroxypropyltrimethoxysilane are added to the above container and stirred at room temperature for 12 hours to obtain the phosphorus-containing quaternary ammonium salt organosiloxane sol; The preparation method of the phosphorus-containing quaternary ammonium salt organosiloxane is as follows: S1 added 17.3g of diethyl chlorophosphate and 50mL of tetrahydrofuran to the reactor, while simultaneously purging with nitrogen for protection. Then, 9g of N,N-dimethylethanolamine and 3g of triethylamine were added and the mixture was stirred in an ice-water bath for 4 hours. After the reaction was complete, the organic solvent tetrahydrofuran was removed by vacuum distillation and filtered to obtain (triethyl phosphate) N,N-dimethylamine. In a reactor equipped with a stirrer, condenser, and thermometer, S2 was added to 22.5 g of N,N-dimethylamine (triethyl phosphate), 24 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and 140 g of isopropanol. The mixture was stirred and stirred until homogeneous, and then refluxed at 70 °C until the reactants became transparent. The reaction was then carried out for another 2 hours. The isopropanol was then removed under 0.01 MPa to obtain a viscous liquid, which is a phosphorus-containing quaternary ammonium salt organosiloxane.

2. The method for preparing a PLA composite fabric according to claim 1, characterized in that: The functional film is a TPU film with a thickness of 0.012-0.015 mm.

3. The method for preparing a PLA composite fabric according to claim 1, characterized in that, The specific steps for laminating the PLA substrate fabric with the functional film are as follows: ① Applying adhesive: First, apply hot melt adhesive to the surface of the PLA substrate fabric and the functional film. ②Lamination: The fabric and film are flatly stacked together, then transferred to a heat press machine. The heat pressing time and temperature are set, and after the temperature is reached, the heat press is performed to complete the heat pressing and lamination, producing PLA composite fabric.

4. The method for preparing a PLA composite fabric according to claim 3, characterized in that: The hot melt adhesive is a polyurethane hot melt adhesive, with a coating amount of 30-40 g / m². 2 .

Images