Transparent Polyamide Mold Resisting Dynamic Bending Fractures

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Solution Overview

Problem

Transparent molds made of polycarbonate are prone to mechanical stress fractures under dynamic bending loads, which can lead to breaks, and existing materials like PMMA and glass do not adequately meet the dynamic capacity requirements for frameless glasses applications.

Innovation Solution

Development of transparent molds using polyamide molding materials with specific monomers such as hexamethylene diamine, bis-(4-amino-3-methylcyclohexyl)methane, and dicarboxylic acids like isophthalic acid, terephthalic acid, or dodecanedioic acid, which provide high light transmission and alternating bend resistance, allowing the molds to withstand significant bending cycles without damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If transparent molds are made of polycarbonate, then they provide good transparency and ease of manufacture, but they are prone to mechanical stress fractures under dynamic bending loads

Engineering Contradiction:
Improveresistance to mechanical stress fracturesVSAvoidsusceptibility to breaks under dynamic load
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the material parameters by selecting specific polyamide compositions (PA 6/12, PA 6/6/12, PA 6/6 T) with particular molecular structures and compositions that provide both high transparency and resistance to dynamic bending loads, achieving at least 60,000 bending cycles without fracture

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite polyamide materials with specific combinations of diamines (HMDA, MACM, PACM) and dicarboxylic acids (IPS, TPS, DDS) to create a material that combines the transparency needed for optical applications with the mechanical strength required to resist stress fractures under dynamic loading conditions

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If traditional materials like PMMA and glass are used, then they provide good transparency, but they do not adequately meet the dynamic capacity requirements for frameless glasses applications

Engineering Contradiction:
Improvelight transmissionVSAvoiddynamic capacity under bending load
Core Design Contradiction:
Illumination intensityVSStrength

Solution Approach 1:

The patent optimizes the material parameters by selecting polyamides with specific glass transition temperatures, molecular weights, and compositions that simultaneously achieve high light transmission (comparable to glass and PMMA) and superior dynamic bending resistance (at least 60,000 cycles), eliminating the trade-off between transparency and strength

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8268956B2Transparent mold made of a polyamide molding material
Publication Date: 2012.09.18 EMS CHEM AG

AI summary

The invention is directed to a transparent mold made of a polyamide molding material containing at least one polyamide formed from at least one diamine selected from the group of hexamethylene diamine (HMDA), bis-(4-amino-3-methylcyclohexyl)methane (MACM) and/or bis-(4-amino-cyclohexyl)methane (PACM) as well as from at least one dicarboxylic acid selected from the group of isophthalic acid (IPS), terephthalic acid (TPS) and/or dodecanedioic acid (DDS) or from the aforementioned diamines and dicarboxylic acids in combination with lactams and/or α-/ω-amino acids.