Shrinkage of polymer coatings on wood veneers in aircraft structure: understanding the causes of the problem and possible solution

飞机橱柜中的一个常见问题是“湿外观”或高光泽饰面的外观劣化，这导致它们最终类似于橙子皮的表面（给出所谓的“橘子皮外观”）。 这是由于一些类型的尺寸不稳定性（或收缩）在清漆覆盖的细木工单板。 问题的可能来源包括清漆的性质、它与木材的相互作用及其随时间演变的方式，以及不同的环境条件（特别是温度和湿度），（当着陆时，飞机舱门打开以适应各种不同的气候，如炎热干燥的沙漠气候、炎热潮湿的沿海气候和寒冷干燥的“西伯利亚”气候）。 这个问题给庞巴迪宇航等公司造成了巨大的时间和金钱损失，因为他们必须面对客户投诉并经常返工橱柜表面，以满足客户的期望。 庞巴迪宇航公司销售的支线和商务飞机的高成本为我们提供了一个机会，可以尝试解决这个问题，从而帮助庞巴迪保持国际竞争优势。 加拿大3M公司的含义是，他们有兴趣了解导致目前问题的根本因素，以帮助确定解决方案。 因此，在这个项目中，我们将尝试通过分析清漆和单板的特性和相互作用，以及它们在暴露于不同温度和湿度水平时随时间的演变，详细了解问题的原因，使用各种适当的科学技术，涉及化学家和木材科学家。 通过获得这些信息，我们希望为庞巴迪和3M加拿大公司提供可能的解决方案，我们也将对其进行测试。 我们预计，所获得的信息也将是有用的一般单板清漆，从而有利于广泛的加拿大工业。

A common problem in aircraft cabinetry is deterioration in the appearance of "wet-look" or high gloss finishes that causes them to eventually resemble the surfaces of orange peels (giving the so-called "orange-peel look"). This is attributed to some kind of dimensional instability (or shrinkage) in the varnish covering the cabinetry veneers. Possible sources of the problem include the nature of the varnish, its interactions with the wood and the ways in which they evolve over time, as well as the different environmental conditions (particularly temperature and humidity) to which the aircraft cabinetry are exposed during their manufacturing and usage (when landed, the aircraft doors are opened to widely varying climates, like hot and dry desert climate, hot and humid coastal climate, and cold and dry "siberian" climate). The problem causes significant loss of time and money to companies like Bombardier Aerospace, because they must frequently rework the cabinetry surfaces in the face of customer complaints and to meet the expectations of their customers. The high cost of the regional and business aircraft sold by Bombardier Aerospace provides an opportunity to try to get to the bottom of this problem, and thereby help Bombardier maintain a competitive edge internationally. The implication of 3M Canada is their interest in understanding the underlying factors that give rise to the present problems in order to help identify solutions. Therefore, in this project, we will try to understand in detail the reasons for the problem by analyzing both the varnish and veneer properties and interactions, and their evolution over time when exposed to different temperatures and levels of humidity, using a large variety of appropriate scientific techniques that involve both chemists and wood scientists. With the information gained, we hope to supply Bombardier and 3M Canada with possible solutions that we will also test. We anticipate that the information gained will also be useful generally for veneer varnishes, and thus benefit a wide range of Canadian industry.