Hand Sandable Body Filler Using Soy-Based Polyester Resin

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Solution Overview

Problem

Traditional unsaturated polyester resins used in body fillers and putties for metal and plastic substrates have limitations in impact strength and adhesion to metal substrates, leading to reduced sandability when modified for improved physical properties, and require pneumatic sanding equipment, which is not always accessible.

Innovation Solution

A two-part resin system incorporating soy-based polyester with a dual curing mechanism, including addition polymerization and oxidative curing, along with specific filler compositions and additives, allowing for improved sandability and reduced need for pneumatic sanding equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If premium unsaturated polyester resins are used to improve UV resistance and air dry qualities, then surface finish quality is improved, but impact strength and adhesion to metal substrates deteriorate

Engineering Contradiction:
Improvesurface finish qualityVSAvoidimpact strength and adhesion
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent uses a composite resin system combining unsaturated polyester resin (UPR) with soy-based polyester resin and reactive bio-derived oils. This composite approach allows the filler to achieve both premium surface finish qualities from the UPR component and improved impact strength and adhesion from the soy-based component, resolving the contradiction between surface quality and mechanical properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the resin system by incorporating soy-based polyester resin (3-60 wt%) and reactive bio-derived oils (0-30 wt%) into the traditional UPR formulation. This parameter change transforms the resin's physical properties to achieve both excellent sandability and improved mechanical strength without compromising surface finish quality.

Inventive Principle:
Principle #35Parameter changes

2Strength

If lower cost, more flexible, tougher unsaturated polyester resins are blended to improve impact strength and adhesion, then physical properties are improved, but sandability deteriorates

Engineering Contradiction:
Improveimpact strength and adhesionVSAvoidsandability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent creates a composite resin system where soy-based polyester resin (3-60 wt%) provides flexibility and toughness for improved impact strength, while the specific formulation with unsaturated polyester resin and controlled reactive monomers maintains optimal sandability. The composite structure allows both properties to coexist without the trade-off present in traditional blends.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent precisely controls the composition parameters including soy-based polyester (3-60 wt%), unsaturated polyester resin (0-57 wt%), and reactive monomers (0-30 wt%) to achieve the optimal balance between flexibility for strength and rigidity for sandability, eliminating the need for compromise found in conventional formulations.

Inventive Principle:
Principle #35Parameter changes

3Strength

If traditional body filler compositions are used to achieve proper physical properties, then mechanical strength is maintained, but pneumatic sanding equipment is required which reduces accessibility

Engineering Contradiction:
Improvemechanical strengthVSAvoidaccessibility and equipment requirement
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent modifies the resin composition parameters by incorporating soy-based polyester resin and controlling the particle size distribution of fillers (talc 1-20 microns, calcium carbonate 2-10 microns). These parameter changes produce a cured filler with optimized hardness and surface characteristics that enable effective hand sanding while maintaining mechanical strength, removing the dependency on pneumatic equipment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a hand-sandable filler that replicates the performance characteristics of pneumatic-sanded fillers. By carefully formulating the resin system and filler composition, the product achieves comparable surface finish quality and mechanical properties that can be obtained through manual sanding, making it a substitute for pneumatic equipment in many applications.

Inventive Principle:
Principle #26Copying

4Strength

If more flexibility is built into the filler by altering the resin composition, then impact strength is improved, but sandability worsens

Engineering Contradiction:
Improveimpact strengthVSAvoidsandability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent uses a composite resin system where soy-based polyester resin provides the flexibility needed for impact strength, while the specific combination with unsaturated polyester resin and controlled cross-linking through reactive monomers maintains the rigidity required for good sandability. The composite structure balances these opposing requirements.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the chemical composition parameters including the ratio of soy-based polyester (3-60 wt%) to unsaturated polyester resin (0-57 wt%) and the amount of reactive monomers (0-30 wt%) to achieve the precise balance between flexibility for impact resistance and structural rigidity for sandability, resolving the contradiction through parameter optimization.

Inventive Principle:
Principle #35Parameter changes

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 system provides enhanced sandability matching pneumatic sanding standards, improved solvent resistance, and extended working time, making repairs more accessible and cost-effective for hand sanding and reducing the likelihood of 'blushing' from solvent absorption.

Implementation Method 1

a dual curing mechanism, including addition polymerization and oxidative curing

Methodology Applied
Scientific EffectAddition polymerization: Photopolymerisation

Implementation Method 2

a dual curing mechanism, including addition polymerization and oxidative curing

Methodology Applied
Scientific EffectOxidative curing: Oxidation

Data Source

PatentEP2726562B1Hand sandable fast repair body filler/putty/primer surfacer
Publication Date: 2018.04.25 ILLINOIS TOOL WORKS INC

AI summary

A body filler resin composition for a two-part resin system is described. In one embodiment, the body filler resin composition includes a polymer having fatty acid functionality, and at least one filler. A two-part resin system and a method of repairing a part using the body filler composition are also described.