Propylene Polymer Composition Flame Retardant Cable Insulation
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Solution Overview
Problem
Existing thermoplastic polymer compositions for electric cables and insulation materials face challenges in achieving a balance between flexibility, mechanical strength, heat resistance, scratch resistance, and flame retardancy while maintaining low brittleness and surface stickiness, particularly in applications where chlorine-based materials are undesirable due to environmental concerns and recycling difficulties.
Innovation Solution
A thermoplastic polymer composition comprising 5-64.9% propylene-based polymers with specific melting points, 0-59.9% lower melting point propylene-based polymers, 0.1-30% graft-modified propylene-based polymers, and 35-75% inorganic fillers such as talc, metal hydroxides, or metal oxides, which are melt-kneaded with ethylene-based polymers and oils to enhance mechanical properties and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyvinyl chloride is used as sheath material for electric cables, then flexibility and flame retardancy are improved, but chlorine gases are generated by heating and recycling becomes difficult
Solution Approach 1:
The invention extracts and eliminates chlorine-based materials from the polymer composition, replacing them with chlorine-free alternatives such as polypropylene and inorganic fillers. This removes the harmful chlorine gas generation while maintaining the essential flame retardancy and flexibility properties through carefully selected filler combinations and polymer blends.
Solution Approach 2:
The invention changes the chemical composition parameters by specifying precise ranges of polypropylene (5-64.9%), lower melting point propylene-based polymer (0-59.9%), graft-modified propylene-based polymer (0.1-30%), and inorganic filler (35-75%). These parameter changes enable the material to achieve flame retardancy without chlorine, while maintaining flexibility and preventing harmful gas generation.
2Strength
If crosslinked polyethylene is used as insulation material, then mechanical strength and electrical properties are improved, but thermoplasticity is lost and recycling becomes difficult
Solution Approach 1:
Instead of using crosslinked polyethylene which loses thermoplasticity, the invention inverts the approach by using thermoplastic polypropylene-based compositions that inherently maintain thermoplasticity. The mechanical strength is achieved not through crosslinking but through optimized filler content (35-75% inorganic filler) and polymer blending, thereby preserving recyclability and thermoplastic processing capabilities.
Solution Approach 2:
The invention creates a composite material system combining polypropylene-based polymers with inorganic fillers (talc, metal hydroxides, metal oxides). This composite structure provides the necessary mechanical strength and electrical insulation properties while maintaining the thermoplastic nature of the base polymer, enabling both performance and recyclability.
3Strength
If hardness is increased to improve scratch resistance, then surface durability is improved, but brittleness increases and low-temperature property deteriorates
Solution Approach 1:
The invention applies preliminary action by pre-modifying the propylene-based polymer through grafting with vinyl compounds containing polar groups or silane compounds before compounding. This preliminary modification creates a polymer matrix with enhanced interfacial adhesion and controlled crystallinity, allowing the final composition to achieve scratch resistance through surface hardening while maintaining ductility and low-temperature flexibility through the carefully selected polymer blend ratios.
Data Source
AI summary
Propylene-based resin compositions contain an inorganic filler in a high ratio and are excellent in flexibility, mechanical strength, elongation at break, heat resistance, scratch resistance, whitening resistance and flame retardancy. Shaped articles comprise the compositions.A first propylene-based resin composition of the present invention contains 5 to 64.9% by weight of a propylene-based polymer (A) having a melting point, as measured by differential scanning calorimetry (DSC), in the range of 120° C. to 170° C.; 0 to 59.9% by weight of a propylene-based polymer (B) having a melting point, as measured by differential scanning calorimetry (DSC), of less than 120° C. or having no observed melting point; 0.1 to 30% by weight of a graft-modified propylene-based polymer (C) obtained by graft modifying a propylene-based polymer having a melting point, as measured by differential scanning calorimetry (DSC), of less than 120° C. or having no observed melting point; and 35 to 75% by weight of an inorganic filler (D) (here, the total amount of (A), (B), (C) and (D) is 100% by weight).