Optical Fiber Buffer Tube Using Polypropylene Composite

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Solution Overview

Problem

Current fiber optic cable protective components, such as buffer tubes, face challenges in achieving high crush resistance, micro-bending resistance, low brittleness temperature, and cost-effectiveness, particularly due to the high cost of materials like polybutylene terephthalate (PBT) and limitations in using high-crystallinity polypropylene.

Innovation Solution

Development of an extruded optical cable protective component using a polymeric blend comprising crystalline polypropylene with a crystallinity of at least 55% combined with an impact-modifying polymer like olefin multi-block interpolymer or olefin block composite, which enhances mechanical properties without the need for expensive materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polybutylene terephthalate (PBT) is used for buffer tubes, then high crush resistance and micro-bending resistance are achieved, but material cost increases significantly

Engineering Contradiction:
Improvecrush resistanceVSAvoidmaterial cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent uses a composite material system consisting of high-crystallinity polypropylene (55-95 wt%) combined with impact-modifying polymer (5-45 wt%). This composite achieves the mechanical performance of expensive PBT materials while using cost-effective polypropylene as the base, thereby reducing material cost while maintaining crush resistance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies that the polypropylene must have a crystallinity of at least 55% (preferably 60-90%). By controlling and optimizing the crystallinity parameter of the polypropylene, the material achieves enhanced mechanical properties including crush resistance, while remaining cost-effective compared to PBT

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If high-crystallinity polypropylene is used, then cost-effectiveness is improved, but impact toughness and resistance to brittleness are reduced

Engineering Contradiction:
Improvematerial costVSAvoidimpact toughness
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent creates a composite material system where high-crystallinity polypropylene (提供成本效益和高结晶性) is combined with impact-modifying polymer (提供冲击韧性). The impact-modifying polymer acts as a toughening agent that absorbs impact energy, preventing the brittle failure characteristic of high-crystallinity polypropylene while maintaining cost-effectiveness

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces localized soft phases (impact-modifying polymer) within the hard crystalline polypropylene matrix. This creates a multi-phase structure where the impact-modifying polymer domains (5-45 wt%) are distributed throughout the polypropylene matrix, providing localized energy absorption and crack propagation resistance, thereby improving impact toughness without sacrificing the overall structural integrity and cost advantages

Inventive Principle:
Principle #3Local quality

3Strength

If impact-modifying polymers are added to polypropylene, then impact toughness is improved, but grease compatibility may be compromised

Engineering Contradiction:
Improveimpact toughnessVSAvoidgrease compatibility
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent carefully controls the composition parameters: polypropylene content (55-95 wt%) and impact-modifying polymer content (5-45 wt%). By optimizing these ratios, the material achieves sufficient impact toughness while maintaining adequate grease compatibility. The high polypropylene base content ensures good grease resistance, while the controlled amount of impact-modifying polymer provides necessary toughness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a multi-phase structure where the impact-modifying polymer exists as dispersed phases (5-45 wt%) within the continuous polypropylene matrix. This localized distribution ensures that the majority of the material (polypropylene phase) maintains good grease compatibility, while the dispersed impact-modifying polymer phases provide localized toughness enhancement without significantly compromising overall grease resistance

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3058407B1Optical fiber cable components
Publication Date: 2020.07.29 DOW GLOBAL TECHNOLOGIES LLC
  • EP3058407B1 patent drawingFigure 1~2
  • EP3058407B1 patent drawingFigure 3
  • EP3058407B1 patent drawing

AI summary

Optical cable components fabricated from an extrudable polymeric blend of crystalline polypropylene modified with one or more impact-modifying polymers. The impact-modifying polymers are selected from an olefin multi-block interpolymer, an olefin block composite, and combinations thereof. Optionally, the polymeric blend can further comprise an elastomer other than the impact-modifying polymer. The polymeric blend may also contain one or more additives. The optical fiber cable components can be selected from buffer tubes, core tubes, and slotted core tubes.