Aqueous moisture-permeable waterproof composition
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Solution Overview
Problem
Conventional aqueous polyurethane resins used in outdoor products suffer from inadequate moisture permeability, waterproofness, and wash durability, especially in extreme conditions, and the addition of melamine-based crosslinking agents does not sufficiently enhance these properties, leading to water ingress and loss of performance after washing.
Innovation Solution
An aqueous moisture-permeable waterproof composition comprising an aqueous polyurethane resin with a specific molecular weight range, combined with an aqueous crosslinking agent and foaming agent, and optionally a thermo-responsive shape memory polymer, to create a solvent-free formulation that enhances waterproofness and moisture permeability, maintaining performance after multiple washes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aqueous polyurethane resin is used to replace conventional solvent-containing resins, then environmental friendliness is improved, but moisture permeability and waterproofness are insufficient
Solution Approach 1:
The patent combines aqueous polyurethane resin with specific crosslinking agents (isocyanate-based, epoxy-based, aziridine-based, or melamine-based) and foaming agents to create a composite aqueous composition. This composite approach maintains the environmental benefits of aqueous resins while significantly improving moisture permeability and waterproofness through the synergistic effects of the added components.
Solution Approach 2:
The patent specifies precise parameter ranges for the aqueous polyurethane resin (weight average molecular weight of 1000-10000 g/mol) and the amounts of crosslinking agent (0.1-15.0 parts by weight) and foaming agent (0.1-15.0 parts by weight) based on 100 parts by weight of resin. These optimized parameters enable the composition to achieve both environmental friendliness and superior waterproofness and moisture permeability.
2Reliability
If melamine-based aqueous crosslinking agent is added to aqueous polyurethane resin, then moisture permeability and waterproofness are enhanced, but wash durability is insufficient
Solution Approach 1:
The patent creates a three-component composite system combining aqueous polyurethane resin, crosslinking agent, and foaming agent. The foaming agent introduces porous structures that maintain stability after washing, while the crosslinking agent forms a durable network. This composite approach ensures that the enhanced moisture permeability and waterproofness are maintained after multiple washings.
Solution Approach 2:
The inclusion of foaming agent creates a porous structure within the aqueous polyurethane resin matrix. This porous structure provides pathways for moisture permeability while the crosslinked network maintains the structural integrity after washing, ensuring long-term durability of the waterproof and moisture-permeable properties.
3Reliability
If conventional films are made from oily solvent-containing resins, then waterproofness is achieved, but harmful VOCs are released
Solution Approach 1:
The patent extracts and eliminates the harmful solvent component from the resin formulation, replacing it with an aqueous-based system. This extraction of the harmful element (solvent/VOC) while maintaining the essential function (waterproofness) through aqueous polyurethane resin and its additives achieves both environmental sustainability and protective performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition achieves excellent waterproofness and moisture permeability before and after washing, demonstrating superior wash durability and resistance to hydrostatic pressure, making it suitable for outdoor products.
Implementation Method 1
an aqueous crosslinking agent is often used alongside an aqueous polyurethane resin
Implementation Method 2
an aqueous foaming agent
Data Source
AI summary
An aqueous moisture-permeable waterproof composition includes an aqueous polyurethane resin having a weight average molecular weight ranging from 1000 g/mol to 10000 g/mol, an aqueous crosslinking agent, and an aqueous foaming agent. The aqueous moisture-permeable waterproof composition is free from a solvent. The aqueous crosslinking agent is present in an amount ranging from 0.1 parts by weight to 15.0 parts by weight and the aqueous foaming agent is present in an amount ranging from 0.1 parts by weight to 15.0 parts by weight, based on a total amount of the aqueous polyurethane resin as 100 parts by weight. The aqueous crosslinking agent is selected from the group consisting of an isocyanate-based aqueous crosslinking agent, an epoxy-based aqueous crosslinking agent, an aziridine-based aqueous crosslinking agent, a melamine-based aqueous crosslinking agent, and combinations thereof.