Processing low density poly(urethane-isocyanurate) rigid foam boards still remains challenging, especially for high thickness panels. In particular, subsequent shrinkage of the foam panel during cooling and cross-linking of the matrix creates in-plane compressive stresses in the facing that can be relieved by buckling with a relatively uniform wavelength of a few millimeters. An extensive study in the scientific literature documents the variety of wrinkling morphologies obtained when a thin film bonded on top of a soft substrate is compressed, and we proposed to apply this model in order to explain experimental observations of wrinkling in the case of a flexible facing bonded to a poly(urethane-isocyanurate) rigid foam. The wavelength, amplitude, and pattern of the waves were found to give information about the mismatch in Young’s modulus as well as the level of compressive strain in the foam panel at the moment of wrinkling formation. A shore durometer (type 00) was systematically used to quickly probe the mechanical properties of the foam surface at various locations along the width of the insulation panel (after removal of the facing) and was found to be a valuable tool to explain the location of surface wrinkling and its evolution with time. Variations in mechanical properties of the foam surface were explained in terms of differences in cell orientation near the surface.

中文翻译：

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聚（氨基甲酸酯-异氰脲酸酯）硬质泡沫板中二维皱纹的自发形成

加工低密度聚（氨基甲酸酯-异氰脲酸酯）硬质泡沫板仍然具有挑战性，尤其是对于高厚度面板。特别是，泡沫板在冷却和基体交联过程中的后续收缩会在面层中产生面内压应力，该压应力可以通过几毫米的相对均匀的波长屈曲来缓解。科学文献中的一项广泛研究记录了粘合在软基材顶部的薄膜被压缩时获得的各种起皱形态，我们建议应用该模型来解释在柔性饰面情况下的起皱实验观察粘合到聚（氨基甲酸酯 - 异氰脲酸酯）硬质泡沫上。波长、幅度、发现波的形状和模式可以提供有关杨氏模量不匹配的信息，以及在起皱形成时泡沫板中的压缩应变水平。肖氏硬度计（00 型）被系统地用于沿着绝缘板的宽度（在去除饰面后）的不同位置快速探测泡沫表面的机械性能，并被发现是一种有价值的工具来解释泡沫表面的位置。表面起皱及其随时间的演变。泡沫表面机械性能的变化是根据表面附近的泡孔取向的差异来解释的。肖氏硬度计（00 型）被系统地用于沿着绝缘板的宽度（在去除饰面后）的不同位置快速探测泡沫表面的机械性能，并被发现是一种有价值的工具来解释泡沫表面的位置。表面起皱及其随时间的演变。泡沫表面机械性能的变化是根据表面附近的泡孔取向的差异来解释的。肖氏硬度计（00 型）被系统地用于沿着绝缘板的宽度（去除饰面后）的不同位置快速探测泡沫表面的机械性能，并被发现是解释泡沫表面位置的宝贵工具。表面起皱及其随时间的演变。泡沫表面机械性能的变化是根据表面附近的泡孔取向的差异来解释的。