Phenolic Resin Foam Board Density Uniformity
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Solution Overview
Problem
Conventional methods for producing phenolic resin foam boards face challenges in achieving uniform density distribution and dimensional stability, especially in thicker products, leading to issues with heat conductivity, compression strength, and dimensional stability, due to uneven foaming and curing processes.
Innovation Solution
A phenolic resin foam board with a thickness of 40 mm to 200 mm is produced by slicing it into multiple pieces and measuring their densities to ensure a uniform density distribution, using a static mixer in a distribution pipe to homogenize the foamable resin composition, and adjusting the ejection temperature to suppress internal heat generation, resulting in a closed cell ratio of 80% or more and a density between 15 kg/m³ and 60 kg/m³.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature condition is set for producing foam board product at high speed, then productivity is improved, but internal temperature of foamable resin composition excessively increases causing cell coarsening and low densification
Solution Approach 1:
The foamable resin composition is divided into multiple ejection portions along the thickness direction, with each portion ejected at different temperatures. This segmentation allows the central part to be ejected at lower temperature to prevent excessive heat generation and cell coarsening, while surface portions can be ejected at higher temperatures to maintain productivity.
Solution Approach 2:
Different ejection temperatures are applied to different portions of the foamable resin composition based on their position in the thickness direction. The central part receives lower temperature ejection to control internal heat generation, while surface portions receive higher temperature ejection to maintain production speed and ensure proper foaming.
2Manufacturing precision
If heating temperature during foaming and curing is set to low to suppress internal heat generation, then cell structure is improved, but production rate decreases and heating furnace length must be extended
Solution Approach 1:
The ejection process is segmented into multiple portions with different temperature settings. By ejecting the central part at lower temperature and surface portions at higher temperature, the system achieves both good cell structure quality and maintained production rate without needing to extend the heating furnace.
Solution Approach 2:
The ejection temperature parameter is changed based on the position in the thickness direction. This parameter change allows optimization of both cell structure and production efficiency by matching temperature conditions to the specific requirements of different portions of the foamable resin composition.
3Productivity
If multiple ejection nozzles are used to supply foamable resin composition at high speed, then productivity is improved, but density gradient increases in thickness direction
Solution Approach 1:
Each ejection nozzle is assigned a specific ejection temperature according to its position in the thickness direction. This local quality approach ensures that despite using multiple nozzles for high productivity, the density distribution remains uniform by compensating for position-dependent variations in heat generation and foaming behavior.
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 method ensures sufficient compression strength, heat conductivity, and dimensional stability in phenolic resin foam boards, even for thicker products, by maintaining a uniform density distribution and preventing excessive internal heat generation during the foaming and curing process.
Implementation Method 1
using a static mixer in a distribution pipe to homogenize the foamable resin composition
Implementation Method 2
a phenolic resin foam board having a thickness of 40 mm to 200 mm or less, in which a density distribution in a thickness direction is homogenized
Implementation Method 3
during the foaming and curing process
Data Source
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AI summary
The present invention provides a phenolic resin foam board, which exhibits sufficient compression strength and heat conductivity for practical use even if a product has an increased thickness, and has excellent dimensional stability as compared with a conventional product. The present invention is a phenolic resin foam board having a thickness of 40 mm or more to 300 mm or less, when the phenolic resin foam board is sliced, from one main surface of the phenolic resin foam board, along the main surface into n pieces (n ≥ 5) at approximately equal intervals of 8 mm or more to 10 mm or less in a thickness direction, a density of an n-th specimen is dn, an average density of n pieces of specimens is dave, a lowest density among the densities of n pieces of specimens is dmin, 0 ≤ (dave - dmin) / dave ≤ 0.12 is established, and when values for Di = (di + d(i + 1)) / 2 are calculated [in which i represents an integer of 1 to (n-1)], Di values are plotted in order of a numerical value of i (in which a horizontal axis indicates i values and a vertical axis indicates Di values), and points corresponding to the Di values are connected, resulting in a density distribution curve, no straight line parallel to the horizontal axis intersects the density distribution curve at four points.