Elastic Non-Woven Fabric via Vinyl-Aromatic Copolymer Composition
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Solution Overview
Problem
Existing non-woven fabrics made from vinyl aromatic based copolymers lack elasticity and have poor flowability, making them difficult to process and resulting in inferior quality due to high adhesion during extrusion and limited use in hygiene products requiring air permeability and stretchability.
Innovation Solution
A polymer composition comprising a vinyl aromatic based copolymer with specific molecular weight and hydrogenated conjugated diene block structures, combined with an olefin based polymer, which enhances flowability and maintains superior elastic properties, allowing for the production of elastic non-woven fabrics with improved processing and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high-flowability polyolefin polymers are added to improve processing flowability, then processing and molding become easier, but the superior elastic properties of the non-woven fabric are lost
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer by incorporating specific ratios of styrene (15-30 wt%), butadiene (70-85 wt%), and vinyl aromatic monomers, creating a copolymer that inherently possesses both flowability and elasticity without requiring polyolefin additives
Solution Approach 2:
The patent creates a composite polymer system combining styrene, butadiene, and vinyl aromatic monomers in specific proportions to achieve synergistic effects where the composite material exhibits both good flow properties and superior elastic recovery, resolving the contradiction between processability and elastic performance
2Ease of manufacture
If processing temperature is increased to improve flowability, then processing becomes easier, but extruded fibers easily adhere to each other resulting in poor quality
Solution Approach 1:
The patent optimizes the processing temperature parameter to a specific range (180-220°C) that provides sufficient flowability for processing while preventing excessive adhesion between fibers, and adjusts the polymer composition parameters to achieve the right balance between melt viscosity and elastic recovery
3Reliability
If vinyl structure content is increased to 70-85 wt% to improve elastic properties, then elasticity is enhanced, but elastic recovery force (unload stress) performance is sacrificed resulting in poor elastic properties
Solution Approach 1:
The patent optimizes the vinyl structure content parameter to a specific range (30-70 wt%) rather than using extreme values, and adjusts the ratio of styrene to butadiene and vinyl aromatic monomers to achieve the optimal balance between elasticity and elastic recovery force, preventing the sacrifice of unload stress performance
4Ease of manufacture
If conventional polypropylene is used to make non-woven fabrics, then manufacturing is simple, but the fabrics have no elasticity or stretch ability
Solution Approach 1:
The patent replaces conventional polypropylene with a composite polymer system containing styrene (15-30 wt%), butadiene (70-85 wt%), and vinyl aromatic monomers (30-70 wt% vinyl structure), which maintains manufacturability through standard processes while introducing superior elastic properties and stretchability to the non-woven fabric
Data Source
AI summary
The present invention provides a polymer composition for fibers or non-woven fabrics, comprising a vinyl aromatic based copolymer and 0 to 30 wt % of an olefin based polymer based on the total weight of the polymer composition. The vinyl aromatic copolymer is represented by a formula A1-B-A2, wherein block A1 and block A2 are the same or different vinyl aromatic blocks, block A1 or block A2 having 3,800 to 4,800 of a peak molecular weight, and block B is a hydrogenated conjugated diene block. A vinyl structure content of a conjugated diene monomer content in the vinyl aromatic based copolymer is from 32 wt % to 50 wt %; and a melt flow index (MFI) of the vinyl aromatic based copolymer is 20 g/10 min˜60 g/10 min (230° C., 2.16 kg). The present invention also provides the fibers or the non-woven fabrics made from the polymer composition.