Random Propylene-Ethylene Copolymer Composition for Low Soluble Fraction
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Solution Overview
Problem
Existing propylene-ethylene copolymers struggle to achieve a balanced improvement in optical, mechanical, and sealing properties without increasing the soluble fraction content, limiting their applicability in food contact and medical applications.
Innovation Solution
A monophasic propylene-ethylene random copolymer composition comprising two propylene-ethylene random copolymer fractions with defined ethylene contents and high relative content of isolated to block ethylene sequences, produced using a single-site catalyst in a two-step polymerization process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high ethylene content is used to improve mechanical properties, then impact strength increases, but soluble fraction content increases limiting applicability
Solution Approach 1:
The patent changes the distribution parameters of ethylene sequences by controlling the I(E) ratio and using specific catalyst systems to achieve a bimodal molecular weight distribution with high impact strength while maintaining low soluble fraction content through precise parameter control in polymerization
Solution Approach 2:
The invention creates a composite polymer structure with two distinct propylene-ethylene random copolymer fractions having different ethylene contents and sequence distributions, combining the benefits of high impact strength from the first fraction with low soluble fraction from the second fraction
2Illumination intensity
If optimized copolymer composition is used to improve optical properties, then transparency increases, but mechanical properties deteriorate
Solution Approach 1:
The patent optimizes optical properties by controlling the ethylene content and sequence distribution parameters to achieve high transparency while maintaining mechanical integrity through the specific bimodal composition and I(E) ratio control
3Temperature
If optimized copolymer composition is used to improve sealing properties, then sealing temperature decreases, but optical properties deteriorate
Solution Approach 1:
The invention controls the ethylene sequence distribution and copolymer composition parameters to achieve appropriate sealing temperature while preserving optical clarity through precise control of the bimodal fraction composition
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 composition achieves improved optical, mechanical, and sealing properties while maintaining a low soluble fraction content, suitable for films requiring a balanced performance.
Implementation Method 1
polymerizing propylene and ethylene comonomer units in a first polymerization reactor in the presence of a single-site catalyst to produce a first polymerization mixture comprising the first propylene-ethylene random copolymer fraction (R-PP1)
Data Source
Figure 1~2
AI summary
A monophasic propylene-ethylene random copolymer composition (R-PP), comprising: a) 30 to 70 wt.-% of a first propylene-ethylene random copolymer fraction (R-PP1), having an ethylene content in the range from 0. 1 to 5.0 mol-%; b) 30 to 70 wt.-% of a second propylene-ethylene random copolymer fraction (R-PP2), having an ethylene content in the range from 0. 1 to 10.0 mol-%; wherein [C2(R-PP)]/[C2(R-PP1)] is more than or equal to 1.00, having a melting temperature in the range from 120 to 145 °C, a content of 2, 1 -regiodefects in the range from 0.05 to 1.40 mol-%, a relative content of isolated to block ethylene sequences, I(E) of more than or equal to 70.0% and fulfilling inequation (I): I(E) - 3.79[C2(R-PP)] ≥ 52.0 (I).