Polyurethane Composites Lightweight Fillers Flexural Strength
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Solution Overview
Problem
Low-density polyurethane composites face compromised mechanical and physical properties, particularly in flexural strength and handleability, as density decreases, limiting their applications.
Innovation Solution
Incorporating a combination of particulate fillers with bulk densities of 1 g/cm3 or greater and lightweight fillers with densities between 0.01 g/cm3 and 1 g/cm3, along with highly reactive polyols and isocyanates, to create polyurethane composites with improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If low density polyurethane composites are made by adding gaseous phase in-situ or using blowing agents, then density is reduced, but flexural strength and handleability decrease sharply
Solution Approach 1:
The patent applies composite materials by combining polyurethane binder with a specific mixture of lightweight fillers (such as expanded perlite, expanded clay, or foamed glass) and particulate fillers (such as fly ash or calcium carbonate). This composite approach allows the material to achieve low density while maintaining flexural strength, as the lightweight fillers provide buoyancy and the particulate fillers provide structural reinforcement, resolving the contradiction between density reduction and strength maintenance.
Solution Approach 2:
The patent changes the physical and chemical parameters of the composite by controlling the particle size distribution, bulk density ratios, and surface treatments of the fillers. Specifically, it uses lightweight fillers with bulk densities of 0.01-0.6 g/cm³ combined with particulate fillers having bulk densities of 1-2.5 g/cm³, and adjusts their proportions to optimize both density and flexural strength, thereby resolving the technical contradiction.
2Weight of stationary object
If low density polyurethane composites are made by adding gaseous phase in-situ or using blowing agents, then density is reduced, but handleability decreases sharply
Solution Approach 1:
The patent uses a composite formulation combining lightweight fillers (expanded perlite, expanded clay, or foamed glass) with particulate fillers (fly ash or calcium carbonate) in specific proportions. This composite structure provides both low density and improved handleability, as the particulate fillers create a more cohesive and manageable matrix while the lightweight fillers reduce overall weight, resolving the contradiction between density reduction and handleability maintenance.
Solution Approach 2:
The patent optimizes handleability by controlling parameters such as the bulk density ratio of lightweight to particulate fillers (specifically using lightweight fillers with bulk densities of 0.01-0.6 g/cm³), particle size distribution, and surface treatments. These parameter adjustments ensure the composite remains easy to handle and install while achieving low density, resolving the technical contradiction.
3Weight of stationary object
If lightweight fillers are used to reduce density, then density is improved, but mechanical properties are compromised
Solution Approach 1:
The patent resolves this contradiction by creating a composite system where lightweight fillers (expanded perlite, expanded clay, or foamed glass) are combined with particulate fillers (fly ash or calcium carbonate) and a polyurethane binder. The lightweight fillers provide the necessary density reduction, while the particulate fillers and binder matrix work together to maintain mechanical integrity and reliability, ensuring both low density and acceptable mechanical properties are achieved.
Solution Approach 2:
The patent maintains mechanical properties while reducing density by optimizing parameters including the bulk density of lightweight fillers (0.01-0.6 g/cm³), the proportion of particulate filler (35-90 wt%), and the polyol hydroxyl number (>250 mg KOH/g). These parameter controls ensure that mechanical properties remain adequate while achieving the desired low density, resolving the technical contradiction.
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 composite achieves enhanced flexural strength and handleability while maintaining reduced density, with flexural strength exceeding 300 psi and handleability increasing significantly, suitable for various applications including building materials.
Implementation Method 1
a polyurethane formed by the reaction of (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, and (ii) one or more polyols
Implementation Method 2
a lightweight filler having a bulk density from 0.01 g/cm3 to less than 1 g/cm3
Data Source
AI summary
Polyurethane composites and methods of preparation are described herein. The polyurethane composites can comprise (a) a polyurethane formed by the reaction of (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, and (ii) one or more polyols, (b) a particulate filler having a bulk density of 1 g/cm3 or greater, (c) optionally a fiber material, and (d) a lightweight filler having a bulk density from 0.01 g/cm3 to less than 1 g/cm3. In some examples, the lightweight filler can be selected from expanded perlite, expanded clay, foamed glass, and combinations thereof. Articles such as building materials comprising the polyurethane composites are also disclosed.