Thermoplastic Elastomer Blends for Degradation-Resistant Films
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Solution Overview
Problem
Conventional elastomeric films used in disposable hygiene articles, such as those based on styrene-isoprene-styrene (SIS) block copolymers, face issues like thermal, oxidative, and UV degradation, and are costly to produce, while alternatives are not easily compatible with existing manufacturing equipment and processes.
Innovation Solution
A thermoplastic elastomer compound is developed by blending different polyolefin elastomers with styrene-ethylene/butylene-styrene block copolymer and plasticizer, enabling good high-speed processing on incumbent equipment and achieving desirable properties like softness, elasticity, and low hysteresis at a lower cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SIS-based elastomeric films are used, then good elasticity and softness are achieved, but thermal, oxidative, and UV degradation occur
Solution Approach 1:
The patent uses a composite material system consisting of polyolefin elastomer (5-40 wt%), SEBS block copolymer (30-60 wt%), and plasticizer (5-20 wt%). This composite approach combines the advantages of different materials: polyolefin provides thermal and UV stability, SEBS provides elasticity and softness similar to SIS, and plasticizer enhances processability. The synergistic combination resolves the degradation issue while maintaining the desired mechanical properties.
Solution Approach 2:
The patent specifies precise parameter ranges for each component to optimize performance: polyolefin elastomer at 5-40 wt%, SEBS at 30-60 wt%, and plasticizer at 5-20 wt%. Additionally, the melt flow rate is controlled within specific ranges (MFR230°C: 2-15 g/10min, MFR190°C: 0.5-5 g/10min). These parameter controls ensure the material achieves both degradation resistance and desired elasticity/softness.
2Reliability
If material composition is changed to improve performance properties, then elasticity and softness are enhanced, but high speed processability is negatively affected
Solution Approach 1:
The patent carefully balances composition parameters to achieve both performance and processability. The SEBS content (30-60 wt%) is optimized to provide sufficient elasticity while maintaining processability. The plasticizer content (5-20 wt%) is specifically controlled to enhance high-speed processability by reducing viscosity, while not compromising the elastic properties provided by SEBS. The melt flow rate specifications ensure both good processability and desired mechanical properties.
Solution Approach 2:
The plasticizer acts as an intermediary substance that facilitates high-speed processing without compromising the elastic properties. It reduces the viscosity and improves flow characteristics during processing, while the SEBS block copolymer maintains the elasticity and softness. This intermediary approach allows independent optimization of processability and performance properties.
3Productivity
If material composition is changed to improve high speed processability, then manufacturing efficiency is enhanced, but performance properties are negatively affected
Solution Approach 1:
The plasticizer serves as an intermediary that improves high-speed processability through viscosity reduction and enhanced flow characteristics, while the SEBS block copolymer (30-60 wt%) ensures that elasticity and softness properties are maintained. The plasticizer enables efficient manufacturing without compromising the performance properties provided by the elastomeric components.
Solution Approach 2:
The composite material system combines three components with complementary functions: polyolefin elastomer provides thermal stability, SEBS block copolymer provides elasticity and softness, and plasticizer provides processability. This composite approach allows simultaneous optimization of both processability and performance properties that would be difficult to achieve with a single material.
4Reliability
If conventional SIS-based elastomeric films are used, then good elasticity is achieved, but manufacturing cost increases
Solution Approach 1:
The patent employs a composite material system that replaces expensive SIS-based elastomers with a cost-effective combination of polyolefin elastomer (5-40 wt%), SEBS block copolymer (30-60 wt%), and plasticizer (5-20 wt%). This composite approach achieves comparable or superior elasticity and softness properties while reducing material costs. The polyolefin component, in particular, provides cost advantages while the SEBS ensures adequate elastic performance.
Data Source
AI summary
A thermoplastic elastomer compound includes a polyolefin elastomer blend of at least two different polyolefin elastomers, styrene-ethylene/butylene-styrene block copolymer, and plasticizer. The compound has a Melt Flow Rate (230° C., 2.16 kg) of no less than about 5 g/10 min and a Melt Flow Rate (190° C., 2.16 kg) of no less than about 1 g/10 min. Elastomeric films formed from the compound can be used in place of elastomeric films based on styrene-isoprene-styrene (SIS) block copolymers to make components of disposable hygiene articles.