Foamed Urethane Cushion Hard Segment Control
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Solution Overview
Problem
Conventional foamed urethane cushion materials for vehicle seats have low durability over time, leading to reduced comfort and performance due to high hygrothermal compression permanent set and inadequate load distribution, which affects vibration absorption and impact resilience.
Innovation Solution
A cushion material comprising a foamed urethane with a specific composition of diphenylmethane diisocyanate-based hard and soft segments, characterized by a spin-spin relaxation time of 20-40 μsec and a volume abundance ratio of 5-40% for the hard segment, and a compression permanent set of 1% or less after 50% compression under hygrothermal conditions, enhancing durability and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional foamed urethane cushion materials are used, then initial cushioning performance is provided, but durability over time deteriorates due to high hygrothermal compression permanent set
Solution Approach 1:
The patent applies parameter changes by precisely controlling the spin-spin relaxation time (T2) of the hard segment to 20-40 μsec and the volume abundance ratio of the hard segment to 5-40%. These specific parameter ranges optimize the molecular structure to resist hygrothermal compression permanent set while maintaining cushioning performance, directly resolving the contradiction between initial performance and long-term durability
Solution Approach 2:
The patent uses composite materials by creating a foamed urethane with a specific composite structure containing hard segments and soft segments in defined proportions. The hard segment (20-40 μsec T2) provides structural stability and resistance to permanent deformation, while the soft segment provides cushioning comfort, achieving both durability and comfort simultaneously
2Reliability
If foamed urethane with higher hard segment content is used to improve durability, then compression permanent set resistance improves, but vibration absorption and impact resilience deteriorate
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the spin-spin relaxation time parameter to 20-40 μsec and volume abundance ratio to 5-40%. This optimized parameter range creates a balanced structure where the hard segment provides sufficient compression resistance while the soft segment maintains vibration absorption and impact resilience capabilities
Solution Approach 2:
The patent applies local quality by creating distinct hard and soft segments with different properties within the foamed urethane structure. The hard segments (with specific T2 and abundance ratio) are distributed to provide localized structural support and compression resistance, while the soft segments provide localized cushioning and vibration absorption, achieving both requirements simultaneously
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 cushion material exhibits improved durability and comfort by reducing shear deformation and maintaining physical properties over time, with a hygrothermal compression permanent set of 1% or less, ensuring effective load distribution and enhanced vibration absorption.
Implementation Method 1
a foamed urethane which is a reaction cured product formed using an isocyanate component of a diphenylmethane diisocyanate compound and which includes a hard segment and a soft segment
Implementation Method 2
the spin-spin relaxation time T2 of the hard segment in the foamed urethane is from 20 μsec to 40 μsec and the volume abundance ratio of the hard segment is from 5% to 40%
Data Source
AI summary
Provided is a foamed urethane containing a cushion material, the foamed urethane containing a hard segment and a soft segment, in which the foamed urethane is a reaction cured product formed using an isocyanate component of an MDI compound. In a first aspect, a spin-spin relaxation time (T2) of the hard segment in the foamed urethane is from 20 μsec to 40 μsec, and a volume abundance ratio of the hard segment is from 5% to 40%. In a second aspect, a foamed urethane includes: a first region in which T2 of the hard segment is from 30 μsec to 40 μsec, and a volume abundance ratio of the hard segment is from 10% to 40%, and a second region in which T2 of the hard segment is from 20 μsec to less than 30 μsec, and a volume abundance ratio of the hard segment is from 5% to 40% in a H1 solid-state pulse NMR measurement, and which is adjacent to the first region.