Objective The effects of different pretreatment processes on the anti-mildew and anti-corrosion properties of wood scrimber were studied in order to find the best treatment method to improve the performance in outdoor environment.

Method The traditional boiling method, microwave method and innovative minimally invasive method were used to pretreat the wood scrimber, and the organic iodide 3-iodo-2-propynyl butylcarbamate (IPBC) was used for impregnation and coated with isocyanate adhesive (MDI). The control efficacy of three treatment processes was analyzed by mildew prevention and anti-corrosion test, and the influence of three treatment processes on the quality of wood scrimber was studied by porosity, mechanical properties and dimensional stability.

Result (1) Through the minimally invasive pretreatment process, the total porosity of the wood scrimber increased by 64.1%, and the drug load increased by 88.0%. (2) The results of mildew test showed that the infection grade of wood scrimber against Aspergillus niger and Botryodiplodia theobromae was 4, while the infection grade of wood scrimber after minimally invasive pretreatment/IPBC soaking was 0. In addition, the anti-loss performance of wood scrimber through MDI loading was improved by 63.0%. (3) The results of anti-corrosion test showed that the wood scrimber had only grade Ⅱ rot resistance to white rot fungi and brown rot fungus, while the wood scrimber after minimally invasive pretreatment/IPBC dipping process had grade Ⅰ rot resistance for both fungi. (4) The results of mechanical and dimensional stability tests showed that the wood scrimber after the minimally invasive pretreatment/IPBC immersion process effectively ensured excellent mechanical properties and dimensional stability. Compared with the original wood scrimber, the flexural strength and short beam shear strength increased by 14.9% and 17.4%, respectively, and the width expansion rate and thickness expansion rate decreased by 25.0% and 49.2%, respectively.

Conclusion The wood scrimber prepared by the minimally invasive pretreatment/IPBC dipping process has excellent control effect on mold, stain fungi and decay fungi, while ensuring excellent mechanical properties and dimensional stability. In addition, the minimally invasive process is green and simple, which can effectively solve the outdoor application problem of wood scrimber.