Aerogels from Isocyanates and Epoxies

Patent Title: ORGANIC AEROGELS BASED ON ISOCYANATE AND CYCLIC ETHER POLYMER NETWORKS

 Number/Link: WO2017016755

Applicant/Assignee: Henkel

Publication date: 2-feb-2017

Gist”: Isocyanate and epoxy are reacted in solvent and supercritically dried

Why it is interesting: While most ‘conventional’ aerogels are based on silica, organic aerogels, especially isocyanate-based aerogels, are also well known: polyurethane-, polyurea-, polyamide-, polyimide-, polycarbodiimide- and polyisocyanurate aerogels have all been reported. This invention adds another type of aerogel based on the reaction of isocyanates and cyclic ethers, esp. oxetanes and oxiranes. The isocyanate with a functionality of (pref.) 2 to 3, (e.g. 4,4′-MDI or methylidynetri-p-phenyletriisocyanate) is reacted with a cyclic ether  of (pref.) functionality of 2 to 3, (e.g. N,N-diglycidyl-4-glycidyloxianiline) in a suitable solvent (e.g. DMAc). After washing, the gel is dried with supercritical carbon dioxide. The materials are useful for thermal insulation and are said to have better mechanical properties compared to other organic aerogels.

N,N-Diglycidyl-4-glycidyloxyaniline

N,N-Diglycidyl-4-glycidyloxyaniline

 

 

Expandable Polyurethane Particles for Insulation Panels

Title: POLYURETHANE-BASED EXPANDABLE POLYMER PARTICLES

 Number/Link: WO2014/006182  (German)

Applicant/Assignee: BASF

Publication date: 9-01-2014

Gist”: Microgranules of TPU/PS copolymer containing pentane can be expanded into insulation panels using standard EPS equipment.

Why it is interesting: Contrary to polystyrene, thermoplastic polyurethane cannot be ‘imbued’ with a physical blowing agent like pentane to make steam-expandable particles. This is due a.o. to the high diffusion rate of pentane (e.g.) in TPU.  BASF have now found that by using a TPU/PS copolymer, expandable particles can be prepared which can be used in standard EPS (expandable polystyrene) equipment to make insulation panels. The TPU used is based on 4,4′-MDI, polyTHF and butanediol such that the vicat softening point is below 80°C.   The TPU, in the form of microgranules (0.5-2mm), is swollen in styrene containing dicumylperoxide, dispersed in water and heated to polymerisation.  A blowing agent like (pref) pentane is added to the dispersion as well. The resulting particles are expandable and can be used to make insulation panels of 50-150 kg/m³.

Expandable Polystyrene.

Expandable Polystyrene.