Biodegradable Nonwoven Laminate Using Aliphatic Polyester
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Solution Overview
Problem
Nonwoven fabric laminates, such as SMS laminates, lack biodegradability despite their benefits in applications like wipers and medical garments, necessitating an enhancement in their ability to degrade naturally.
Innovation Solution
A biodegradable nonwoven laminate is developed using spunbond and meltblown layers formed from low melting point aliphatic polyesters with specific thermal and mechanical properties, including a melting point range of 50° C. to 160° C. and apparent viscosity of 20 to 215 Pascal-seconds, which facilitates enhanced processability and strength while ensuring biodegradability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyolefin fibers are used to form nonwoven fabric laminates, then strength and durability are enhanced, but biodegradability is lost
Solution Approach 1:
The patent changes the chemical composition parameters by replacing conventional polyolefin fibers with aliphatic polyester fibers that have specific melting points (50-160°C) and viscosity characteristics. This parameter change enables the laminate to maintain strength while gaining biodegradability, as the polyester fibers can decompose under composting conditions unlike polyolefin fibers.
Solution Approach 2:
The patent creates a composite nonwoven laminate structure combining spunbond layers with meltblown barrier layers formed from aliphatic polyester fibers. This composite structure integrates the strength properties of spunbond layers with the barrier properties of meltblown layers, both contributing to overall laminate performance while maintaining biodegradability through the use of biodegradable polyester materials.
2Object-affected harmful factors
If aliphatic polyester with low melting point is used, then biodegradability is enhanced, but processability may be affected
Solution Approach 1:
The patent optimizes the melting point parameter of the aliphatic polyester to fall within the specific range of 50-160°C, which balances biodegradability with processability. This parameter selection ensures the fiber can be processed using conventional nonwoven fabric manufacturing techniques while maintaining the ability to biodegrade under composting conditions.
Solution Approach 2:
The patent applies different aliphatic polyester formulations with specific viscosity characteristics (20-215 Pascal-seconds at 160°C and 1000 sec⁻¹ shear rate) to different layers of the laminate. The spunbond layers use formulations optimized for strength while the meltblown barrier layer uses formulations optimized for barrier properties, with both maintaining appropriate processability.
3Object-affected harmful factors
If meltblown barrier layer is added between spunbond layers, then fluid and bacteria penetration is inhibited, but laminate complexity increases
Solution Approach 1:
The patent divides the nonwoven laminate into distinct functional layers: outer spunbond layers providing strength and durability, and an inner meltblown barrier layer providing fluid and bacteria penetration resistance. This segmentation allows each layer to be optimized for its specific function while using the same biodegradable aliphatic polyester material throughout, maintaining overall simplicity.
Solution Approach 2:
The patent utilizes the porous structure of the meltblown barrier layer formed from aliphatic polyester microfibers to create a barrier that inhibits fluid and bacteria penetration while maintaining breathability. The porous morphology provides capillary action and physical barrier properties without requiring additional complex structural elements.
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 laminate exhibits improved strength, toughness, and biodegradability, with enhanced peak load and elongation properties, making it suitable for various applications without the need for conventional additives like nucleating agents.
Implementation Method 1
a first aliphatic polyester having a melting point of from about 50° C. to about 160° C.
Implementation Method 2
The first aliphatic polyester, the second aliphatic polyester, or both have an apparent viscosity of from about 20 to about 215 Pascal-seconds
Data Source
AI summary
A biodegradable nonwoven laminate is provided. The laminate comprises a spunbond layer formed from substantially continuous filaments that contain a first aliphatic polyester having a melting point of from about 50° C. to about 160° C. The meltblown layer is formed from microfibers that contain a second aliphatic polyester having a melting point of from about 50° C. to about 160° C. The first aliphatic polyester, the second aliphatic polyester, or both have an apparent viscosity of from about 20 to about 215 Pascal-seconds, as determined at a temperature of 160° C. and a shear rate of 1000 sec-1. The first aliphatic polyester may be the same or different than the second aliphatic polyester.