Propylene Polymer Composition Heat Resistance
Solution Overview
Problem
Propylene-based elastomers face issues with insufficient heat resistance and surface stickiness when exposed to high temperatures for extended periods, limiting their applications in flexible and transparent materials.
Innovation Solution
A propylene-based polymer composition comprising a propylene-based polymer and a propylene/ethylene/α-olefin copolymer with specific molecular weight distribution, isotactic pentad fraction, and B-value, which enhances flexibility, transparency, and heat resistance while preventing stickiness at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If propylene-based elastomers are used to improve flexibility and transparency, then environmental suitability and hygienic qualities are enhanced, but heat resistance is insufficient and surface stickiness occurs at high temperatures
Solution Approach 1:
The invention uses a composite material system consisting of propylene-based polymer (A) and propylene/ethylene/α-olefin copolymer (B) in specific proportions. This composite structure combines the flexibility and transparency of propylene-based elastomers with the heat resistance of polypropylene, resolving the contradiction between ease of operation and temperature resistance.
Solution Approach 2:
The invention changes the compositional parameters by controlling the weight ratio of components (A) and (B) within specific ranges, and by specifying the melting point range of component (A) as 120-170°C. This parameter optimization allows the material to maintain flexibility while achieving sufficient heat resistance.
2Illumination intensity
If propylene-based elastomers are used to achieve transparency and flexibility, then the material is suitable for various applications, but surface stickiness develops when exposed to high temperatures for long periods
Solution Approach 1:
The composite material system of propylene-based polymer (A) and propylene/ethylene/α-olefin copolymer (B) maintains transparency while the specific composition prevents surface stickiness at high temperatures by optimizing the balance between elastomeric and crystalline phases.
Solution Approach 2:
By controlling the melting point of component (A) within 120-170°C and optimizing the weight ratios, the invention adjusts the material's thermal behavior to prevent stickiness while maintaining transparency for long-term high temperature exposure.
3Strength
If flexibilizing materials are added to polypropylene resin compositions to improve flexibility and impact resistance, then mechanical properties are enhanced, but heat resistance deteriorates and surface stickiness occurs
Solution Approach 1:
Instead of adding separate flexibilizing materials that compromise heat resistance, the invention creates an integrated composite where propylene-based polymer (A) provides flexibility and propylene/ethylene/α-olefin copolymer (B) maintains heat resistance, achieving both impact resistance and thermal stability.
Solution Approach 2:
The invention optimizes the compositional parameters and melting point characteristics to achieve a balance where impact resistance is improved through the elastomeric component while heat resistance is preserved through the controlled composition and crystalline structure of the copolymer.
Data Source
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AI summary
It is an object of the present invention to provide a propylene-based polymer composition which is excellent in transparency and heat resistance (particularly, heat resistance at high heat deformation temperature) and is free from occurrence of stickiness even when it is used at a high temperature for a long period of time. The propylene-based polymer composition of the invention comprises (A) a propylene-based polymer (PP) satisfying the following requirements (1) and (2), in an amount of 1 to 99 parts by weight, and (B) a propylene/ethylene/α-olefin copolymer satisfying the following requirements (I) to (IV), in an amount of 99 to 1 part by weight, with the proviso that the total amount of the component (A) and the component (B) is 100 parts by weight; (1) the polymer (A) has a melting point (Tm), as measured by a differential scanning calorimeter (DSC), of not lower than 110°C but not higher than 170°C, (2) the polymer (A) has an isotactic pentad fraction (mmmm fraction) of not less than 90%, (I) the copolymer (B) contains constitutional units derived from propylene in amounts of 73.1 to 87.0% by mol, constitutional units derived from ethylene in amounts of 10.0 to 16.9% by mol and constitutional units derived from an α-olefin of 4 to 20 carbon atoms in amounts of 3.0 to 10.0% by mol, (II) the copolymer (B) has an isotactic triad fraction (mm), as calculated by 13C-NMR, of not less than 85%, and (III) the copolymer (B) has a molecular weight distribution (Mw/Mn, Mw: weight-average molecular weight, Mn: number-average molecular weight, both being in terms of polystyrene), as measured by gel permeation chromatography (GPC), of not more than 3.5.