Cable Coating Polymer Blend for Smooth High-Speed Extrusion

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Solution Overview

Problem

Cable jackets made from solution-phase polymerized ethylene-based resins (SP resins) have poor processability and surface smoothness issues during extrusion, compared to gas-phase polymerized resins (GP resins) with broader molecular weight distribution, limiting their suitability for cable applications.

Innovation Solution

A polymeric composition comprising a broad-molecular-weight-distribution high-density ethylene-based polymer and a narrow-molecular-weight-distribution linear-low-density ethylene-based polymer, blended in specific proportions and extruded at high speeds to form a conductor jacket with improved mechanical and performance properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If solution-phase polymerized ethylene-based resins (SP resins) are used for cable jackets, then mechanical properties can be maintained, but processability and surface smoothness deteriorate during extrusion

Engineering Contradiction:
Improvemechanical propertiesVSAvoidprocessability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies composite materials by blending two distinct polymer types: a gas-phase polymerized ethylene-based resin (broad MWD) and a solution-phase polymerized ethylene-based resin (narrow MWD). This composite approach allows the broad-MWD component to provide excellent processability and surface smoothness during extrusion, while the narrow-MWD component contributes desirable mechanical properties. The synergistic combination resolves the contradiction between maintaining mechanical properties and achieving good processability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes parameter changes by controlling the molecular weight distribution characteristics of the polymer components. Specifically, it combines a polymer with broad molecular weight distribution (I21/I2 ratio of 55-100) with one having narrow distribution (I21/I2 ratio of 1.05-5.0), and optimizes their weight ratio (30-70 wt% broad-MWD, 70-30 wt% narrow-MWD). This parameter optimization enables the composition to exhibit both good processability and acceptable surface smoothness, overcoming the limitations of using narrow-MWD SP resins alone.

Inventive Principle:
Principle #35Parameter changes

2Strength

If solution-phase polymerized ethylene-based resins (SP resins) are used for cable jackets, then mechanical properties can be maintained, but surface smoothness deteriorates at typical extrusion line speeds

Engineering Contradiction:
Improvemechanical propertiesVSAvoidsurface smoothness
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies composite materials by blending two distinct polymer types: a gas-phase polymerized ethylene-based resin (broad MWD) and a solution-phase polymerized ethylene-based resin (narrow MWD). This composite approach allows the broad-MWD component to provide excellent processability and surface smoothness during extrusion, while the narrow-MWD component contributes desirable mechanical properties. The synergistic combination resolves the contradiction between maintaining mechanical properties and achieving good processability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes parameter changes by controlling the molecular weight distribution characteristics of the polymer components. Specifically, it combines a polymer with broad molecular weight distribution (I21/I2 ratio of 55-100) with one having narrow distribution (I21/I2 ratio of 1.05-5.0), and optimizes their weight ratio (30-70 wt% broad-MWD, 70-30 wt% narrow-MWD). This parameter optimization enables the composition to exhibit both good processability and acceptable surface smoothness, overcoming the limitations of using narrow-MWD SP resins alone.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If broader molecular weight distribution gas-phase polymerized resins (GP resins) are used, then processability improves, but the ability to diversify polymeric resin types is limited

Engineering Contradiction:
ImproveprocessabilityVSAvoidresin type diversity
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies composite materials by blending two distinct polymer types: a gas-phase polymerized ethylene-based resin (broad MWD) and a solution-phase polymerized ethylene-based resin (narrow MWD). This composite approach allows the broad-MWD component to provide excellent processability and surface smoothness during extrusion, while the narrow-MWD component contributes desirable mechanical properties. The synergistic combination resolves the contradiction between maintaining mechanical properties and achieving good processability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes parameter changes by controlling the molecular weight distribution characteristics of the polymer components. Specifically, it combines a polymer with broad molecular weight distribution (I21/I2 ratio of 55-100) with one having narrow distribution (I21/I2 ratio of 1.05-5.0), and optimizes their weight ratio (30-70 wt% broad-MWD, 70-30 wt% narrow-MWD). This parameter optimization enables the composition to exhibit both good processability and acceptable surface smoothness, overcoming the limitations of using narrow-MWD SP resins alone.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12142395B2Polymeric compounds for cable coatings and processes for producing same
Publication Date: 2024.11.12 DOW GLOBAL TECHNOLOGIES LLC

AI summary

Coated conductors having a conductor at least partially surrounded by a polymeric composition. The polymeric composition contains a broad-molecular-weight-distribution high-density ethylene-based polymer and a narrow-molecular-weight-distribution linear-low-density ethylene-based polymer, and has a density of at least 0.95 g/cm3. Also disclosed are processes for preparing the polymeric composition and for making the coated conductors. Further disclosed are articles of manufacture containing the same.