Polypropylene Binary Blend for Low Sealing Initiation Temperature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current polypropylene compositions for heat-sealable films face challenges in achieving a balance between low sealing initiation temperature (SIT) and high melting point, often requiring multiple components and compromising on processing properties.
Innovation Solution
A binary blend of two propylene polymer fractions, PPF1 and PPF2, is developed, comprising 30-50 wt% propylene copolymer with 1.50-7.00 mol% C4-C10 alpha-olefin comonomer and 70-50 wt% propylene terpolymer with 0.30-3.00 mol% ethylene and 3.50-12.00 mol% C4-C10 alpha-olefin comonomer, optimizing SIT and melting temperature (Tm) for a broad sealing window and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a low sealing initiation temperature is achieved using multiple polyolefin components, then sealing performance is improved, but device complexity increases
Solution Approach 1:
The invention extracts and eliminates unnecessary components from the polyolefin composition. Instead of using multiple polyolefin components as in prior art, the invention achieves low SIT and high Tm with a simplified composition containing only one polyolefin and one non-polyolefin wax component, thereby reducing complexity while maintaining performance
Solution Approach 2:
The invention uses a composite material approach by combining a polyolefin with a specifically selected non-polyolefin wax (microcrystalline wax, polyalphaolefin wax, or ceresin). This composite achieves the desired low SIT and high Tm properties without requiring multiple polyolefin components, thus simplifying the overall composition
2Temperature
If multiple polyolefin components are used to achieve both low SIT and high Tm, then sealing performance is improved, but manufacturing complexity increases
Solution Approach 1:
The invention removes the complexity of using multiple polyolefin components by extracting only the essential elements: one polyolefin and one non-polyolefin wax. This simplifies manufacturing processes while achieving the required melting temperature and sealing initiation temperature properties
Solution Approach 2:
The invention changes the approach from adjusting multiple polyolefin parameters to controlling the composition ratio between polyolefin and non-polyolefin wax (0.1-10 wt% wax). This parameter change simplifies manufacturing by reducing the number of variables to control while maintaining optimal Tm and SIT
3Strength
If high sealing temperatures are used, then sealing strength is improved, but thermal damage to packaged goods occurs
Solution Approach 1:
The invention changes the temperature parameters by creating a composition that achieves strong sealing at lower temperatures. The non-polyolefin wax component facilitates sealing initiation at lower temperatures while the polyolefin maintains high melting temperature, thus avoiding thermal damage to heat-sensitive goods
Solution Approach 2:
The composite of polyolefin and non-polyolefin wax creates a material that seals at lower temperatures than conventional polyolefins alone. The wax component lowers SIT while the polyolefin maintains structural integrity and high Tm, enabling effective sealing without exposing packaged goods to excessive heat
Data Source
AI summary
The invention relates to a polypropylene composition which combines low sealing initiation temperature (SIT) and high melting point (Tm), thus having a broad sealing window.