Polyamide Injection Welding Material Triamine Units

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Solution Overview

Problem

Current injection welding methods for joining primary molded parts do not achieve sufficient weld strength, despite the use of various polyamide-containing materials, necessitating a more effective approach to enhance the bonding between resin components.

Innovation Solution

A method involving the use of a polyamide injection welding material composed of dicarboxylic acid, diamine, and triamine units, with specific molecular ratios and incorporating an inorganic filler, to achieve high weld strength by optimizing the polyamide's chemical and thermal properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional polyamide-containing injection welding materials are used to join primary molded parts, then welding can be performed with high productivity, but the weld strength between the primary molded parts is insufficient

Engineering Contradiction:
Improvewelding productivityVSAvoidweld strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The invention changes the chemical composition parameters of the polyamide by introducing triamine units (0.05-1 mol%) derived from diamine condensation, and optimizes the dicarboxylic acid unit composition (60-100 mol% aromatic dicarboxylic acid units). This chemical parameter modification enables the material to achieve both high weld strength and maintain injection welding productivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite polyamide structure combining dicarboxylic acid units, diamine units, and triamine units. The triamine units act as a composite component that enhances weld strength while the aromatic dicarboxylic acid units maintain the material's thermal and mechanical properties, achieving both high strength and productivity

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed method results in molded articles with significantly improved weld strength, heat resistance, and chemical resistance, making them suitable for applications in automotive components and other industrial uses.

Implementation Method 1

the polyamide being obtained from a polycondensation of a dicarboxylic acid and a diamine

Methodology Applied
Scientific EffectPolycondensation:

Implementation Method 2

injection welding material containing a polyamide around or between butt weld portions of primary molded parts disposed in face-to-face contact, so as to weld the primary molded parts together

Methodology Applied
Scientific EffectMelting and solidification: Melting

Data Source

PatentEP3047954B1Molded article manufacturing method, injection welding material, and molded article
Publication Date: 2020.03.18 KURARAY CO LTD
  • EP3047954B1 patent drawingFigure 1~2
  • EP3047954B1 patent drawingFigure 3
  • EP3047954B1 patent drawing

AI summary

The present invention provides a method for producing molded articles by joining primary molded parts by injection welding, by which a molded article composed of primary molded parts that are joined with high weld strength can be produced. The present invention relates to a method for producing molded articles including a welding step of injecting an injection welding material containing a polyamide around or between butt weld portions of primary molded parts disposed in face-to-face contact, so as to weld the primary molded parts together to form a molded article. The polyamide contains dicarboxylic acid units and diamine units. This polyamide further contains triamine units in an amount of 0.05 to 1 mol% with respect to the total dicarboxylic acid units.