Fire-Resistant Wood Coating Using Castor Oil Polyurethane

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Solution Overview

Problem

Conventional fire-resistant coatings for wood products do not effectively extend the duration that wood elements can sustain structural loads during a fire, lack durability, and are costly, particularly failing to provide adequate protection against water exposure and flame spread.

Innovation Solution

A fire-resistant coating formulation comprising an aromatic isocyanate, castor oil, and intumescent particles, with specific weight percentages, forming a polyurethane matrix that allows for elasticity and expansion compatibility with intumescent particles, enhancing durability and water resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional fire-resistant coatings are applied to wood products, then flame spread protection is improved, but the duration that wood elements can sustain structural loads during fire is not extended

Engineering Contradiction:

Improveflame spread protectionVSAvoidstructural load duration

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of moving object

Solution Approach 1:

The coating combines intumescent particles (for flame spread protection) with a polyurethane matrix formed from aromatic isocyanate and castor oil (for structural durability). This composite structure allows the coating to simultaneously provide flame resistance and maintain structural integrity during fire exposure, resolving the contradiction between flame spread protection and structural load duration.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If conventional fire-resistant coatings are applied to wood products, then fire protection is improved, but water durability is insufficient

Engineering Contradiction:

Improvefire protectionVSAvoidwater durability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the coating by using aromatic isocyanate and castor oil to form a polyurethane matrix with specific molecular structure and crosslinking density. This parameter change provides both fire protection through intumescent action and water durability through the hydrophobic and chemically resistant nature of the cured polyurethane network.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If treatments that achieve desired fire resistance results are applied, then fire protection is improved, but manufacturing cost increases significantly

Engineering Contradiction:

Improvefire protectionVSAvoidmanufacturing cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent uses castor oil, a relatively inexpensive and readily available natural resource, as the polyol component instead of expensive synthetic polyols. This substitution maintains the fire-resistant functionality through intumescent particles while significantly reducing material costs, making the treatment economically viable for large-scale manufacturing.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Object-affected harmful factors

If a fire-resistant coating provides rigidity for fire protection, then fire resistance is improved, but the coating becomes brittle and loses durability

Engineering Contradiction:

Improvefire resistanceVSAvoidcoating durability

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The polyurethane matrix provides dynamic properties by combining crosslinked rigidity for fire protection with inherent elastomeric flexibility from the castor oil polyol structure. This dynamic balance allows the coating to maintain its protective function during fire exposure while remaining durable and resistant to cracking under normal service conditions.

Inventive Principle:

Principle #15Dynamics

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 coating significantly improves the fire resistance of wood products by maintaining structural integrity and durability, allowing for prolonged exposure to fire and water, while reducing costs through efficient formulation and application.

Implementation Method 1

an aromatic isocyanate present in a quantity ranging from about 15% to about 39% by weight of the coating and castor oil present in a quantity ranging from about 37% to about 65% by weight of the coating

Methodology Applied

Scientific EffectPolyaddition reaction: Chemical Bonding

Implementation Method 2

intumescent particles present in a quantity ranging from about 1% to about 40% by weight of the coating

Methodology Applied

Scientific EffectIntumescent expansion: Thermal Expansion

Data Source

PatentUS8458971B2Fire resistant wood products

Publication Date: 2013.06.11 WEYERHAEUSER NR CO

AI summary

The present disclosure is directed generally towards fire-resistant wood products and formulations for fire-resistant coatings. In some embodiments, the disclosure includes a fire-resistant coating comprising an aromatic isocyanate (present in a quantity ranging from about 15% to about 39%), castor oil (present in a quantity ranging from about 37% to about 65%), and intumescent particles (present in a quantity ranging from about 1% to about 40%). Further aspects are directed towards materials such as wood products coated with fire-resistant coatings according to embodiments of the disclosure.