Heavy Plastic Composite Bonding for High Density and Strength

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Solution Overview

Problem

Existing heavy plastic materials used in timepiece components, filled with metal or ceramic powders, suffer from reduced mechanical properties due to lack of cohesion, impacting their impact resistance and suitability for applications requiring strength and weight.

Innovation Solution

A composite material composition with a filler (50-85% by weight) and polymer (15-50% by weight) bonded via hydrogen, ionic, or coordinate bonds, optionally with a coupling agent, reinforcement, pigment, and diluent/plasticiser, ensuring improved cohesion and mechanical properties like Young's modulus ≥ 2.5 GPa, elongation ≥ 5%, and load at break ≥ 30 MPa.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of stationary object

If metal or ceramic powder is incorporated into polymer to increase density, then the density and weight are improved, but the mechanical properties and cohesion are reduced

Engineering Contradiction:

ImprovedensityVSAvoidmechanical properties

Core Design Contradiction:

Weight of stationary objectVSStrength

Solution Approach 1:

A silane coupling agent is introduced as an intermediary substance between the metal/c ceramic filler and the polymer matrix. The coupling agent contains reactive groups that form chemical bonds with both the filler surface and the polymer chains, acting as a bridge that transfers stress effectively and prevents material separation, thereby maintaining mechanical strength while achieving high density.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a multi-component composite material system consisting of polymer matrix, metal/ceramic filler, and silane coupling agent. This composite structure combines the advantages of each component: the polymer provides flexibility and processability, the filler provides density and weight, while the coupling agent ensures strong interfacial bonding, resulting in a material that achieves both high density and good mechanical properties.

Inventive Principle:

Principle #40Composite materials

2Weight of stationary object

If metal or ceramic filler is added to polymer, then the density is increased, but the impact absorbing capacity is reduced

Engineering Contradiction:

ImprovedensityVSAvoidimpact absorbing capacity

Core Design Contradiction:

Weight of stationary objectVSReliability

Solution Approach 1:

The silane coupling agent serves as a mediator that improves the interface between the rigid filler particles and the polymer matrix. By forming strong chemical bonds, it prevents stress concentration at the interface during impact, reducing the likelihood of crack initiation and propagation, thereby maintaining impact absorbing capacity despite the presence of dense filler material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical and physical parameters of the filler surface through silane treatment. The coupling agent modifies the surface chemistry of the filler, creating a gradient structure that transitions from the rigid filler to the flexible polymer, thereby improving energy dissipation during impact while maintaining high density.

Inventive Principle:

Principle #35Parameter changes

3Weight of stationary object

If metal powder is incorporated into polymer chains, then the density is improved, but the cohesion and material unity are reduced

Engineering Contradiction:

ImprovedensityVSAvoidcohesion

Core Design Contradiction:

Weight of stationary objectVSStability of the object's composition

Solution Approach 1:

The silane coupling agent acts as a molecular bridge that chemically connects the filler particles to the polymer chains. The coupling agent's dual reactivity allows it to bond with both the inorganic filler surface and the organic polymer matrix, creating a unified material structure with strong interfacial adhesion and preventing material separation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention applies local quality modification by treating only the filler surface with silane coupling agent, creating a localized gradient structure. The filler core maintains its high density properties, the interface region gains enhanced bonding capability through coupling agent, and the polymer matrix retains its flexibility, resulting in a material with both high density and strong cohesion.

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 material exhibits enhanced stiffness, elongation, and load-bearing capacity, providing improved impact resistance and tenacity suitable for horological and other applications requiring durability.

Implementation Method 1

the polymer is bonded to the filler and/or the coupling agent is respectively bonded to the filler and to the polymer, when the material comprises at least one coupling agent, by one or more of the following bonds that are a hydrogen bond, a coordinate bond or an ionic bond

Methodology Applied

Scientific EffectHydrogen bonding:

Implementation Method 2

Methodology Applied

Scientific EffectIonic bonding:

Implementation Method 3

Methodology Applied

Scientific EffectCoordinate bonding:

Implementation Method 4

These bonds establish between the oxidised surface, and/or electronic vacancies present at the surface of the filler, and groups of the polymer and/or of the coupling agent

Methodology Applied

Scientific EffectSurface oxidation: Oxidation

Data Source

PatentUS20230416473A1Article made from a heavy plastic material

Publication Date: 2023.12.28 ETA SA MFG HORLOGERE SUISSE

AI summary

An article made from a material having a density between 2 and 7 g/cm3, the material comprising by weight for a total of 100%: a filler (2) made from a metal and/or ceramic material; at least one polymer (4); optionally at least one coupling agent (3) present in a percentage greater than or equal to 0% and less than 10%; optionally at least one reinforcement present in a percentage between 0 and 10%; optionally at least one pigment present in a percentage between 0 and 5%; optionally at least one diluent and/or a plasticiser present in a percentage between 0 and 5%. The polymer (4) is bonded to the filler (2) and the coupling agent (3) is respectively bonded to the polymer (4) and to the filler (2) by one or more bonds chosen from a hydrogen bond, a coordinate bond and an ionic bond.