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CN-122012001-A - Single-component solvent-free polyurethane hot melt adhesive for functional fabric coating and preparation method thereof

CN122012001ACN 122012001 ACN122012001 ACN 122012001ACN-122012001-A

Abstract

The invention provides a single-component solvent-free polyurethane hot melt adhesive for a functional fabric coating and a preparation method thereof, wherein the hot melt adhesive comprises, by weight, 60% -80% of polyether or polyester soft segments, 10% -20% of diisocyanate hard segments, 3% -8% of cross-linking agents and 1% -3% of stabilizer compounds, and is an isocyanate-terminated prepolymer which is solidified by absorbing environmental moisture. The invention abandons the traditional cloth-film-adhesive multilayer physical composite process, and generates the functional coating with a microphase separation structure on the surface of the base cloth in situ by a direct coating and chemical bonding mechanism of single-component PUR adhesive, thereby thoroughly solving the problems of easy delamination, foaming and pain points with plastic feel of the fabric, realizing excellent waterproof air permeability and extreme softness, having no solvent volatilization in the whole process, greatly reducing the manufacturing cost and having extremely high environmental protection and industrialization application values.

Inventors

  • ZHANG LEILEI
  • MIAO YIXIN

Assignees

  • 聚力创材料科技(湖州)有限公司

Dates

Publication Date
20260512
Application Date
20260323

Claims (10)

  1. 1. The single-component solvent-free polyurethane hot melt adhesive for the functional fabric coating is characterized by comprising the following components in percentage by weight: a soft segment polymer, the mass ratio of which is 60 to 80 percent, and one or a mixture of more than one selected from polyether polyol or polyester polyol; the hard segment isocyanate accounts for 10 to 20 percent of the mass and is polyfunctional diisocyanate; a crosslinking agent in an amount of 3 to 8% by mass; The mass ratio of the stabilizing system auxiliary agent is 1-3%, and the stabilizing system auxiliary agent comprises an antioxidant and an ultraviolet stabilizer; The polyurethane hot melt adhesive is a single-component moisture curing adhesive with 100% of solid content, and the isocyanate group with high activity at the tail end is configured to be capable of carrying out crosslinking polymerization reaction with active oxygen-containing groups on the surface of a base fabric and water molecules in the environment so as to form an elastic microporous adhesive film which is chemically bonded with fibers by in-situ crosslinking on the surface of a fabric base material.
  2. 2. The one-component solvent-free polyurethane hot melt adhesive for functional fabric coating according to claim 1, wherein the soft segment polymer is a mixed compound of polytetrahydrofuran ether glycol with number average molecular weight of 2000-4000 g/mol and polyadipate glycol ester, and the hard segment isocyanate is selected from any one or a mixture of 4,4' -diphenylmethane diisocyanate or isophorone diisocyanate.
  3. 3. The one-component solvent-free polyurethane hot melt adhesive for functional fabric coating according to claim 1, wherein when the polyurethane hot melt adhesive is specially used for high waterproof functional fabric coating, the mass ratio of the hard isocyanate is adjusted to 18-20%, and the composition is further added with a hydrophobic modifier with the mass ratio of 0.5-2.0%, wherein the hydrophobic modifier is a polydimethylsiloxane modified leveling auxiliary agent, and the hydrostatic pressure resistance of the polyurethane hot melt adhesive after the polyurethane hot melt adhesive is completely cured into a film is more than or equal to 50kPa.
  4. 4. The one-component solvent-free polyurethane hot melt adhesive for functional fabric coating according to claim 1, wherein when the polyurethane hot melt adhesive is specially used for high-air-permeability soft functional fabric coating, the soft segment polymer adopts pure polyether polyol and the mass ratio of the soft segment polymer is improved to 75-80%, the use of crystalline polyester polyol is eliminated from the composition, the Shore A hardness of a glue layer is maintained to be 30-45 ℃ after the polyurethane hot melt adhesive is completely cured, and the moisture-permeable air-permeability of the glue layer is more than or equal to 100g/m < 2 >. 24h.
  5. 5. The single-component solvent-free polyurethane hot melt adhesive for the functional fabric coating according to claim 1, wherein the density of an internal crosslinking network of the polyurethane hot melt adhesive after complete crosslinking and curing is more than or equal to 1.2mmol/cm & lt 3 & gt, the peel strength of an adhesive layer and a base fabric is more than or equal to 1.5N/25mm, the elongation at break of a system is more than or equal to 150%, the single-component solvent-free polyurethane hot melt adhesive does not contain any volatile organic solvent, and the VOC content of volatile organic compounds detected by the detection system is less than or equal to 50g/L.
  6. 6. A method for preparing a one-component solvent-free polyurethane hot melt adhesive for functional fabric coating according to any one of claims 1 to 5, which comprises the following steps: S1, preprocessing a base material, namely performing surface plasma high-energy activation treatment or corona discharge treatment on textile functional base cloth to remove oil stains and impurities adsorbed on the surface and induce fiber molecular chains to break so as to generate a large number of high-activity oxygen-containing free radicals; S2, melting and precisely coating, namely adding the single-component solvent-free polyurethane hot melt adhesive into an adhesive supply system, heating and melting the single-component solvent-free polyurethane hot melt adhesive to obtain an adhesive solution with fluidity, and then directly and uniformly coating the adhesive solution on the surface of the base fabric subjected to the activation treatment in the step S1 in situ through precise coating equipment; S3, temperature and humidity control chemical crosslinking and curing, namely, pulling the semi-finished base cloth which completes the coating operation into a curing chamber with an accurate environment regulation system, triggering and maintaining isocyanate groups in a glue layer to undergo deep hydrolysis and polyurea crosslinking polymerization reaction by utilizing moisture in the environment; s4, after the glue layer is fully crosslinked and solidified, the fabric is subjected to low-temperature shaping, edge regular cutting and surface electrostatic dust removal, and an integrated film-free fabric finished product with elasticity and functionality is directly obtained.
  7. 7. The preparation method of the single-component solvent-free polyurethane hot melt adhesive for the functional fabric coating, which is disclosed in claim 6, is characterized in that in the step S2, the precise coating equipment adopts a precise adjustable scraper type coater or a screw extrusion type hot melt adhesive machine, the temperature of an adhesive tank of an adhesive supply system is precisely controlled between 120 ℃ and 150 ℃, the coating adhesive quantity per unit area is precisely controlled between 5 and 50g/m < 2 >, and the tape running coating speed of the equipment is adaptively controlled between 10 and 50 m/min.
  8. 8. The method for preparing the single-component solvent-free polyurethane hot melt adhesive for the functional fabric coating according to claim 6, wherein in the step S2, the mechanical gap of the adjustable scraper is cooperatively regulated and controlled to be 0.05-0.5 mm by the servo motor, and the physical pressure of the back pressure roller is regulated and controlled to be 0.3-0.8 MPa in a matching way, so that the uniformity deviation of the thickness of the adhesive layer coated in a large area is strictly controlled within a range of less than or equal to plus or minus 5%, and the occurrence of macroscopic local adhesive coating or microscopic adhesive shortage is effectively avoided.
  9. 9. The method for preparing the single-component solvent-free polyurethane hot melt adhesive for the functional fabric coating according to claim 6, wherein in the step S3, the environment regulation and control system in the curing chamber sets and constantly controls the curing reaction temperature to be within a range of 20-35 ℃, and simultaneously strictly controls the relative humidity in a space to be within an effective reaction range of 40-70%, and the curing time for completing deep crosslinking is 24-48 hours in a standard natural curing mode.
  10. 10. The method for preparing the single-component solvent-free polyurethane hot melt adhesive for the functional fabric coating according to claim 6, wherein the curing process in the step S3 further comprises an accelerated curing operation mode, namely nanometer atomized water vapor is continuously and uniformly introduced into a curing chamber through a selected ultrasonic high-frequency humidity control system, a high-humidity microenvironment of a local space is forcedly maintained, the temperature of a low-temperature setting procedure in the step S4 is set to be 60-80 ℃, and the setting maintaining time is 20-30 minutes.

Description

Single-component solvent-free polyurethane hot melt adhesive for functional fabric coating and preparation method thereof Technical Field The invention relates to the technical field of functional textile fabric and polymer coating materials, in particular to a single-component solvent-free polyurethane hot melt adhesive for functional fabric coating and a preparation method thereof. Background In the manufacture of functional fabrics (mainly covering the fields of high-end outdoor sportswear, special medical protective clothing, high-tech home textiles and the like), the fabrics are required to have both high-grade waterproof and windproof performances and excellent moisture permeability and air permeability. For a long time, a multilayer physical composite process of cloth-film-glue-cloth or cloth-film-glue has been commonly adopted in the industry. However, with the complexity of the end use scenario and the continual escalation of consumer demand for the wearing experience, this traditional physical compounding technology gradually exposes multiple inherent drawbacks that are difficult to overcome: 1. delamination and blister failure due to physical interface stress imbalance: The traditional process is essentially physical stacking of heterogeneous materials, and because of the obvious difference of the tensile modulus, the shrinkage and the thermal expansion coefficient of the fabric base cloth, the laminating adhesive and the functional film, when the garment is in an extreme outdoor temperature difference alternating environment or subjected to mechanical stretching caused by intense human body movement, particularly after multiple daily water washing or industrial water washing, the materials of each layer can generate extremely large interfacial shear stress, the traditional physical adhesive force can not resist the stress tearing for a long time, and irreversible interfacial delamination, local foaming, wrinkling, edge curling and other deadly quality defects are extremely easy to cause the complete failure of the fabric protection function. 2. Comfort bottleneck ("strong plastic feel" and reduced breathability): The functional film has certain rigidity, and the multi-layer composite increases the overall thickness and hardness of the fabric, so that the original drapability and softness of the textile are seriously lost, the fabric has strong 'plastic stiffness feel' when worn, and obvious noise is easy to generate when rubbed, in addition, the main stream microporous film (such as ePTFE), the ventilation mechanism of the fabric depends on micron-sized pores on the surface of the film, and sebum sweat secreted by a human body, external dust particles and detergent residues are very easy to block the micropores in actual wearing, so that the moisture vapor permeability (MVTR) of the fabric is reduced in a cliff type in a short time, and serious stuffy feel is generated. 3. Manufacturing a lengthy and environment-friendly compliance crisis: The traditional film compounding process link is extremely long (film making, adhesive coating, high-temperature hot-pressing compounding, curing and storing), so that equipment investment is high, energy consumption is high, and a large amount of undegraded waste film scraps can be generated in the cutting compounding process. More serious, solvent type adhesives (such as solvents containing DMF, toluene and the like) containing a large amount of Volatile Organic Compounds (VOCs) are often used in the traditional laminating process, which not only threatens the health of production operators, but also cannot meet the increasingly severe ecological environmental protection standard of the current international textile market. Therefore, the technical problems to be solved in the art are: The technical path dependence of the traditional functional film and physical bonding is broken, a polymer coating material which can be directly molded on the surface of the fabric in one step, has spontaneous breathing and ventilation capacity and is soft in hand feeling is developed, meanwhile, the material can form deep molecular-level chemical bonding with the base fabric, and the preparation and molding processes need to realize no solvation, so that the requirement of mass production of a new generation of functional fabric with high efficiency, greenness and cost reduction is met. Disclosure of Invention In view of the defects of the prior art, the invention aims to provide a single-component solvent-free polyurethane hot melt adhesive for functional fabric coating and a preparation method thereof, which are used for solving the problems that the traditional fabric is easy to delaminate and wrinkle due to multilayer physical lamination, loses fabric characteristics due to stiff hand feeling and is complicated and low-efficiency due to multiple production procedures in the prior art. To achieve the above and other related objects, the present invention provides a one-co