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CN-121991402-A - High-performance fluorine-free water-repellent microporous polyolefin functional film and preparation method and application thereof

CN121991402ACN 121991402 ACN121991402 ACN 121991402ACN-121991402-A

Abstract

The invention relates to the technical field of membrane materials, in particular to a high-performance fluorine-free water-repellent microporous polyolefin functional membrane, a preparation method and application thereof. The invention focuses on breaking through the synergic technical problem of light and thin, water repellent and moisture permeable, is based on a light and thin, hydrostatic pressure resistant, moisture permeable and water resistant polyolefin film body, realizes fluorine-free environment protection, ensures the moisture permeability, can form an integrated waterproof moisture permeable composite material with different composite materials through a special composite process, and can be widely applied to application scenes with requirements on light and thin moisture permeability, water pressure resistance and the like of the material.

Inventors

  • GU QIAO
  • FANG YAKUN

Assignees

  • 广东固纳科技有限公司

Dates

Publication Date
20260508
Application Date
20260128

Claims (10)

  1. 1. The preparation method of the high-performance fluorine-free water-repellent microporous polyolefin functional film is characterized by comprising the following steps of: S1, mixing and melt-extruding ultra-high molecular weight polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, lubricant, compatilizer, nano silicon dioxide and crystal structure regulator to form a gel film; s2, carrying out first bidirectional synchronous stretching on the gel film, and then extracting with a solvent to obtain a polyolefin functional film; s3, sequentially carrying out transverse stretching and longitudinal stretching on the polyolefin functional film, and then carrying out heat setting to obtain the high-performance fluorine-free water-repellent microporous polyolefin functional film.
  2. 2. The method according to claim 1, wherein the ultra-high molecular weight polyethylene has a weight average molecular weight of 50 to 500 tens of thousands, and/or the ethylene-vinyl acetate copolymer has a vinyl acetate mass content of 10 to 20%.
  3. 3. The preparation method according to claim 2, wherein the step S1 specifically comprises the steps of first blending ultra-high molecular weight polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer and a lubricant to obtain a first mixture, adding a compatilizer, nano silicon dioxide and a crystal structure regulator into the first mixture, carrying out second blending and melt extrusion to obtain the gel film.
  4. 4. The method according to claim 3, wherein the linear low-density polyethylene is added in an amount of 4 to 8% by mass of the ultra-high molecular weight polyethylene, and the ethylene-vinyl acetate copolymer is added in an amount of 3 to 5% by mass of the ultra-high molecular weight polyethylene.
  5. 5. The preparation method of claim 4, wherein the compatilizer is maleic anhydride grafted polyethylene, the addition amount of the compatilizer is 0.8-2% of the mass of the ultra-high molecular weight polyethylene, the nano silicon dioxide is nano silicon dioxide packaged by the silane coupling agent, the particle size of the nano silicon dioxide is 10-50 nm, and the addition amount of the nano silicon dioxide is 1-3% of the mass of the ultra-high molecular weight polyethylene.
  6. 6. The method according to claim 5, wherein the crystal structure modifier is at least one selected from the group consisting of a phosphate and a sorbitol derivative, the amount of the phosphate added is 0.02% to 0.1% by mass of the ultra-high molecular weight polyethylene, and the amount of the sorbitol derivative added is 0.04% to 0.1% by mass of the ultra-high molecular weight polyethylene.
  7. 7. The method according to claim 6, wherein the step S2 comprises preheating the gel film at 70-95 ℃ and then stretching the film for the first time, stretching the film in a bi-directional synchronous manner at 130-140 ℃ with a stretching ratio of 4-6 times to form an intermediate film with a thickness of 3-100 μm, and extracting the intermediate film with a dichloromethane solution at a rate of 0.5-1 m/min to obtain the polyolefin functional film.
  8. 8. The method according to claim 7, wherein S3 comprises the steps of preheating the polyolefin functional film at 80-90 ℃, performing a second stretching, performing a transverse stretching at 105-115 ℃ by a factor of 3-5, preheating the transversely stretched film at 90-100 ℃ and performing a longitudinal stretching at 120 ℃ by a factor of 3-5, and heat setting the longitudinally stretched film at 110-120 ℃.
  9. 9. A high performance fluorine-free water repellent microporous polyolefin functional film characterized by being obtained according to the preparation method of any one of claims 1 to 8.
  10. 10. The use of the high performance fluorine-free water repellent microporous polyolefin functional film of claim 9 in the field of footwear, apparel, packaging, construction materials.

Description

High-performance fluorine-free water-repellent microporous polyolefin functional film and preparation method and application thereof Technical Field The invention relates to the technical field of membrane materials, in particular to a high-performance fluorine-free water-repellent microporous polyolefin functional membrane, a preparation method and application thereof. Background The waterproof breathable material has wide and urgent demands in the fields of outdoor clothing, medical protection, industrial packaging, building materials and the like, and has the core functions of blocking liquid water (such as rainwater, blood and environmental moisture) and allowing water vapor (such as sweat) to freely pass through, so that dry and comfortable protection of a protected object is realized. Conventional high performance waterproof breathable materials generally rely on fluorochemicals (PFAS, particularly the C8/C6 series) as a finish or coating. These fluorine-containing materials can impart extremely low surface energy to fabrics or films, achieving excellent superhydrophobic effects. However, PFAS has proven to be environmentally persistent, bioaccumulative, and potentially toxic, known as a permanent chemical. With the increasing strictness of global environmental regulations and the enhancement of environmental awareness of consumers, the development of safe, environment-friendly and efficient fluorine-free substitution technology has become a core topic of urgent industry. The realization of fluorine-free waterproof ventilation faces technical challenges (1) how to maintain high hydrostatic pressure resistance, high moisture permeability and durable physicochemical stability of the material after removal of high-performance fluorine-containing chemicals. (2) Fluorine-free alternatives (e.g. silicones, waxes) are often inferior to fluorine-based products in terms of washing resistance, abrasion resistance, weatherability, how to improve their binding fastness to the substrate and their service life are key difficulties. (3) The new fluorine-free technology needs to realize large-scale production without significantly increasing the manufacturing cost and the process complexity. The current mainstream waterproof and moisture permeable film technology mainly follows two major mechanisms of micro-porosity and hydrophilic non-porosity. Microporous membranes are represented by ePE membranes and PTFE membranes, the microporous membranes are water-blocking and moisture-conducting through physical pore diameters, the microporous membranes are the main choice under the environment-friendly trend by virtue of ' no fluorine per se ', high cost performance and high air permeability ', the microporous membranes have excellent performance but face the issue of PFAS environment protection, polyurethane (PU) spans two major mechanisms, the microporous handfeel of the microporous membranes is soft, and hydrophilic non-porous Type (TPU) realizes ' absolute water resistance ' and pollution resistance by virtue of molecular chain chemical transmission, but the air permeability depends on environment humidity. The ePE film has the defects of hard hand feeling, noise and easy pollution by greasy dirt, the PU film is integrally provided with a short plate with air permeability influenced by environment or hidden danger of solvent environmental protection, and the PTFE film of a performance owner has excellent performances, but faces market atrophy due to deadly PFAS environmental protection disputes and high cost. For light and thin fabrics, the realization of high moisture permeability, high hydrostatic pressure resistance and high air permeability simultaneously has technical bottlenecks. The improvement of the waterproof performance is usually carried out at the expense of air and moisture permeability, and the pursuit of light and thin air permeability reduces the water pressure resistance. The existing product is difficult to realize the cooperative optimization of the three performances under the constraint condition of light weight and thinness. Conventional porous waterproof breathable films, such as ePE, have pores formed by a pore former, have non-uniform pore size distribution and generally have low structural strength, so that high hydrostatic pressure and high moisture permeability cannot be combined at the same time. The existing fluorine-free waterproof finishing agent or film has the advantages that the water repellent effect is easy to lose efficacy rapidly after abrasion, washing or long-term use, the hydrostatic pressure resistance of the fabric is reduced rapidly, and the service life of the product is short. Because the air/moisture permeability of the film is often attenuated under the influence of a composite process (dispensing), how to realize the light, thin, air/moisture permeability, water resistance and washing resistance of the composite fabric is very critical based on the optimized selection of