PFA Copolymer Composition for Heat-Resistant Injection-Molded Bolts

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Solution Overview

Problem

Conventional TFE-based copolymers used in bolts deform at high temperatures and lose axial tension, leading to loosening, and lack sufficient moldability for injection molding of PFA, which is required for forming bolts with suppressed deformation.

Innovation Solution

A copolymer containing 3.5 to 4.2% PPVE unit, a melt flow rate of 18.0 to 22.0 g/10 min, and 50 or less functional groups per 10^6 main-chain carbon atoms, enabling excellent moldability, abrasion resistance, oxygen and chemical solution impermeability, creep resistance, and high-temperature rigidity, even at low mold temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional TFE-based copolymer is used for bolts, then chemical resistance is improved, but high-temperature deformation resistance deteriorates

Engineering Contradiction:
Improvechemical resistanceVSAvoidhigh-temperature deformation resistance
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent applies parameter changes by precisely controlling the PPVE unit content (3.5-4.2% by mass), melt flow rate (18.0-22.0 g/10 min at 372°C), and functional group content (50 or less per 10^6 main-chain carbon atoms). These parameter optimizations enable the copolymer to achieve both chemical resistance and high-temperature deformation resistance, resolving the contradiction between these two properties.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional TFE-based copolymer is used for injection molding, then moldability is improved, but high-temperature rigidity deteriorates

Engineering Contradiction:
ImprovemoldabilityVSAvoidhigh-temperature rigidity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent optimizes the melt flow rate to 18.0-22.0 g/10 min at 372°C, which provides excellent moldability for injection molding while maintaining high-temperature rigidity. This precise parameter control allows the material to be easily molded yet retain structural integrity at elevated temperatures.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by stationary object

If low mold temperature is used for injection molding, then energy consumption is reduced, but molding precision deteriorates

Engineering Contradiction:
Improveenergy consumptionVSAvoidmolding precision
Core Design Contradiction:
Use of energy by stationary objectVSManufacturing precision

Solution Approach 1:

The copolymer's optimized melt flow rate and molecular structure enable successful injection molding at low mold temperatures while maintaining beautiful surface finish and dimensional accuracy. The material's rheological properties allow it to flow and fill molds effectively even at lower temperatures, reducing energy consumption without sacrificing molding precision.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If extrusion forming is used for coating small-diameter wires, then productivity is improved, but coating uniformity deteriorates

Engineering Contradiction:
Improvecoating productivityVSAvoidcoating uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes the melt flow rate to 18.0-22.0 g/10 min, which provides ideal rheological properties for extrusion coating on small-diameter wires. This parameter optimization ensures uniform coating thickness and smooth surface finish while maintaining high coating speed and productivity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12540208B2Copolymer, molded body, injection molded body, and coated electrical wire
Publication Date: 2026.02.03 DAIKIN INDUSTRIES LTD

AI summary

A copolymer containing tetrafluoroethylene unit and perfluoro (propyl vinyl ether) unit, wherein the copolymer has a content of perfluoro (propyl vinyl ether) unit of 3.5 to 4.2% by mass with respect to the whole of the monomer units, a melt flow rate at 372° C. of 18.0 to 22.0 g/10 min, and the number of functional groups of 50 or less per 106 main-chain carbon atoms.