Polyamide Moulding Compound Soft-Touch Surface

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Solution Overview

Problem

Existing polyamide moulding compounds fail to achieve a balance between a soft-touch surface and excellent physical properties, such as high modulus of elasticity in tension and breaking elongation, in moulded articles.

Innovation Solution

A polyamide moulding compound comprising an amine-terminated, amorphous polyamide blended with styrene-ethylene/butylene-styrene copolymer and its maleic anhydride-grafted counterpart, along with reinforcing materials and additives, maintaining a specific weight ratio to achieve a soft-touch surface with superior mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a block copolymer composition is used to produce a soft-touch surface, then the surface softness is improved, but the modulus of elasticity in tension deteriorates

Engineering Contradiction:
Improvesoft-touch surfaceVSAvoidmodulus of elasticity in tension
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent uses a composite material system consisting of amine-terminated amorphous polyamide as the base matrix, combined with styrene-ethylene/butylene-styrene copolymer (SEBS) and its maleic anhydride graft (SEBS-MAH) as plasticizers. This composite formulation allows the material to simultaneously achieve soft-touch surface properties and high modulus of elasticity in tension, resolving the contradiction between surface softness and tensile rigidity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the weight ratio parameters of the components, specifically maintaining a polyamide to plasticizer ratio in the range of 1.25:0.75 to 0.75:1.25. By precisely controlling these compositional parameters, the material achieves both soft-touch surface characteristics and high tensile modulus, demonstrating how parameter optimization resolves the contradiction between surface properties and mechanical strength.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If a block copolymer composition is used to achieve soft-touch properties, then the surface haptics are improved, but the breaking elongation deteriorates

Engineering Contradiction:
Improvesoft-touch surfaceVSAvoidbreaking elongation
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The composite system of amine-terminated amorphous polyamide with SEBS and SEBS-MAH plasticizers creates a material that maintains both soft-touch surface properties and high breaking elongation. The specific interaction between the polyamide matrix and the block copolymer plasticizers enables simultaneous achievement of surface haptics and tensile ductility.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

By optimizing the weight ratio parameters within the range of 1.25:0.75 to 0.75:1.25, the patent achieves a balance where the material exhibits both soft-touch characteristics and high breaking elongation. This parameter optimization ensures that neither surface haptics nor tensile ductility are compromised.

Inventive Principle:
Principle #35Parameter changes

3Strength

If conventional polyamide is used to maintain high modulus of elasticity, then the tensile strength is improved, but the soft-touch surface property deteriorates

Engineering Contradiction:
Improvemodulus of elasticity in tensionVSAvoidsoft-touch surface
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies local quality by using amine-terminated amorphous polyamide as the base matrix that provides high modulus of elasticity, while incorporating SEBS and SEBS-MAH plasticizers that provide soft-touch surface properties. The specific local interaction between these components allows different regions of the material to exhibit different properties, resolving the contradiction between tensile strength and surface softness.

Inventive Principle:
Principle #3Local quality

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 compound produces moulded articles with a soft-touch surface and exceptional mechanical properties, including high modulus of elasticity in tension, breaking elongation, and notch impact strength, suitable for various applications like housings and grips.

Implementation Method 1

a blend of an amine-terminated, amorphous polyamide and styrene-ethylene/butylene-styrene copolymer and also styrene-ethylene/butylene-styrene copolymer grafted with maleic anhydride

Methodology Applied
Scientific EffectPlasticization:

Implementation Method 2

an amine-terminated, amorphous polyamide as polyamide

Methodology Applied
Scientific EffectPolymer chain bonding: Chemical Bonding

Implementation Method 3

styrene-ethylene/butylene-styrene copolymer grafted with maleic anhydride

Methodology Applied
Scientific EffectChemical grafting: Chemical Bonding

Data Source

PatentUS8604120B2Polyamide moulding compound for producing moulded articles with a soft-touch surface and also corresponding moulded articles
Publication Date: 2013.12.10 EMS PATENT AG

AI summary

The invention relates to a polyamide moulding compound for producing moulded articles with a soft-touch surface, the polyamide moulding compound comprising a blend of an amine-terminated, amorphous polyamide and styrene-ethylene/butylene-styrene copolymer and also styrene-ethylene/butylene-styrene copolymer grafted with maleic anhydride. The invention relates furthermore to moulded articles which are produced with this moulding compound and the use thereof.