All posts in category Adhesives-Coatings

Insulating Wood-Aerogel Composites

Title: REINFORCED ORGANIC NATURAL FIBER COMPOSITES

Number/Link: WO2015/144267

Applicant/Assignee: Huntsman

Publication date: 1-10-2015

“Gist”: Aerogel particles are incorporated in composite wood boards

Why it is interesting: Composite wood products (OSB, MDF..) are well known and popular construction materials which are produced by compressing wood fibers (or flakes and the like) together with a binder like e.g. a polymeric MDI. Typically these materials show thermal conductivity values of about 50 mW/m.K at densities of around 200 kg/m³. According to this invention these insulation values can be significantly improved by incorporating (a large amount of) hydrophobic nanoporous particles and binding the composite with an in-water emulsified isocyanate. In the examples silica aerogel particles and wood fibers are mixed an bonded with an emulsifiable MDI. The amount of particles ranges from about 25 to 50% (w/w) resulting in composites with densities below 200 kg/m³ and insulation values of about 20 to 30 mW/mK.

Medium density fibreboard (MDF).

3 Comments

by Gerhard Bleys on October 2, 2015 • Permalink

Posted in Adhesives-Coatings, composites

Tagged acoustics, aerogel, bio-based materials, composites, Construction, dispersions, energy, Environment, hydrophobic, Insulation, nano, nanoporous, renewable materials, silica

Posted by Gerhard Bleys on October 2, 2015

https://purpatents.com/2015/10/02/insulating-wood-aerogel-composites/

Hybrid Hotmelt Adhesive with Low Free Isocyanate

Title: POLYURETHANE HOT-MELT ADHESIVE HAVING A LOW CONTENT OF DIISOCYANATE MONOMERS AND GOOD CROSS-LINKING SPEED

Number/Link: WO2015/135833 (German)

Applicant/Assignee: Sika

Publication date: 17-09-2015

“Gist”: Use of mercaptosilane to reduce free monomeric diisocyanate

Why it is interesting: Reduction of the amount of free monomeric diisocyanate in adhesives, coatings, OCF systems etc. remains a hot topic in industrial polyurethane research, mostly because of changing legislation. For example, in the EU the amount of free MDI needs to be below 1% in order to avoid “R-40” (suspect carcinogen) labeling. A number of strategies to reduce free isocyanate have been tried in the past (and mentioned in this blog). Examples are distillation, the use of asymmetric diisocyanates and the use of monols. According to this invention the amount of free monomeric isocyanate in a hotmelt formulation can be reduced by adding a mercaptosilane like e.g. mercaptopropyltrimethoxysilane. The mercaptosilane is said to react preferentially with the monomeric isocyanate. Only a relatively small amount of mercaptosilane is used such that the main curing mechanism is still the isocyanate-water reaction.

Mercaptopropyltrimethoxysilane

PU Sealants using Michael Addition Chemistry

Title: MICHAEL ACCEPTOR-TERMINATED URETHANE-CONTAINING FUEL RESISTANT PREPOLYMERS AND COMPOSITIONS THEREOF

Number/Link: US2015/0252232

Applicant/Assignee: PRC-DeSoto

Publication date: 10-09-2015

“Gist”: A PU prepolymer is capped with Michael accepting groups and then cured with a dithiol

Why it is interesting: This invention is about sulphur containing PU sealants with properties acceptable for the aerospace industry. A bis(vinylsulfonyl)- terminated urethane-polythioether prepolymer is prepared according to the scheme below. The prepolymer can then be cured with a dithiol-ended polyether, catalysed by a tertiary amine. The compositions have an extended pot life and the curing rate can be controlled by using an encapsulated tert-amine as a controlled-release catalyst.

Michael acceptor-terminated prepolymer preparation according to the invention

Innovation in Polyurethanes

All posts in category Adhesives-Coatings

Insulating Wood-Aerogel Composites

Hybrid Hotmelt Adhesive with Low Free Isocyanate

PU Sealants using Michael Addition Chemistry

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