Polyamide Resin Composition for Mobile Telephone Housings

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Solution Overview

Problem

Mobile telephone housings require materials with high stiffness and low moisture absorption to maintain structural integrity and electromagnetic signal transparency, but existing polyamide compositions often fail to meet these criteria due to significant moisture absorption, which affects signal strength and power consumption.

Innovation Solution

A polyamide composition comprising 20-70 weight percent of aliphatic and semiaromatic polyamides with reinforcing agents and impact modifiers, resulting in a tensile modulus greater than 12 GPa and moisture absorption of less than 0.4 weight percent, ensuring excellent stiffness and low moisture absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If thermoplastic polyamide compositions are used for mobile telephone housings, then good physical properties and moldability are achieved, but significant moisture absorption occurs which decreases transparency to electromagnetic radiation

Engineering Contradiction:
ImprovemoldabilityVSAvoidmoisture absorption
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite material system consisting of polyamide resin combined with reinforcing agents (such as glass fibers, carbon fibers, or metal fibers) and impact modifiers. This composite structure maintains the moldability of thermoplastic polyamides while the reinforcing agents provide structural integrity and the impact modifiers reduce moisture absorption, achieving both ease of manufacture and resistance to moisture absorption.

Inventive Principle:
Principle #40Composite materials

2Strength

If polyamide compositions with good mechanical properties are used, then structural support and impact resistance are achieved, but moisture absorption increases which affects electromagnetic signal transmission

Engineering Contradiction:
Improveimpact resistanceVSAvoidmoisture absorption
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical and physical parameters of the polyamide composition by selecting specific resin types (such as polyamide 6, polyamide 12, or their copolymers) and controlling their molecular weight, crystallinity, and composition. By adjusting these parameters and combining them with reinforcing agents and impact modifiers, the material achieves high impact resistance while minimizing moisture absorption through optimized compositional parameters.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If polyamide 12 is used, then good resistance to moisture absorption is achieved, but insufficient stiffness for mobile telephone housing applications

Engineering Contradiction:
Improvemoisture absorptionVSAvoidstiffness
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent combines polyamide 12 with reinforcing agents such as glass fibers, carbon fibers, or metal fibers to create a composite material that maintains the low moisture absorption properties of polyamide 12 while significantly enhancing its stiffness and structural strength. The reinforcing agents provide the necessary mechanical rigidity for telephone housing applications without compromising the inherent moisture resistance of the polyamide 12 base material.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS8853324B2Mobile telephone housing comprising polyamide resin composition
Publication Date: 2014.10.07 CELANESE POLYMERS HLDG INC

AI summary

A mobile telephone housing comprising a polyamide composition having excellent stiffness and low moisture absorption.