Solid-Solid PU PCM

Patent Title: PHASE-CHANGE MATERIAL FOR STORING THERMAL ENERGY, MANUFACTURING METHOD AND USES OF SUCH A MATERIAL

 Number/Link:  WO2017/198933 (French)

Applicant/Assignee:  UNIV CERGY-PONTOIS

Publication date: 23 november 2017

Gist”: A crosslinked PEG-HMDI elastomer can be used as phase change material.

Why it is interesting: Phase change materials, used to dampen temperature cycles in buildings, are well known. Most organic phase change materials (e.g. paraffines) show solid-liquid phase transitions and therefore need to be macro- or micro-encapsulated. This invention is about polyurethane PCMs with a solid to solid phase transition, and therefore need not be encapsulated. The PU PCM is prepared by reacting a polyethylene glycol with a diisocyanate like HMDI together with a crosslinker like glycerol. The solid elastomer is then ground into powder which can be used in construction materials like plaster or cement. The transition temperature and the latent heat of the PCM is controlled through the mole weight of the PEG (e.g. 1000 to 2000 Da) and the degree of crosslinking.
Solid-solid PU PCMs are not new, see WO2011/089061 (Huntsman), which (in my opinion) presents a more elegant and flexible solution to the problem.

Phase_Change_Materials

Temperature damping by PCM (Wikimedia Commons)

 

Formic Acid Blown EPIC Foams

Patent Title: ISOCYANATE-BASED TEMPERATURE-RESISTANT FOAMS WITH HIGH FLAME RESISTANCE

 Number/Link: WO2016/131874

Applicant/Assignee: BASF, Covestro

Publication date: 25-08-2016

Gist”:  One shot rigid isocyanate-epoxy foams blown with formic acid

Why it is interesting: This is the first in a series of (at least) 3 patent applications apparently resulting from a cooperation between BASF and Covestro on epoxy-isocyanate (“EPIC”) foams.  The other applications are WO2016/131878 and WO2016/131880 published on the same date. More publications may follow.
The current invention is about temperature-resistant foams with reportedly very high mechanical properties prepared form a one-shot system comprising a (pref.) high functional MDI, a (pref.) bisphenol-A or bisphenol-F polyglycidylether, at least one reactive amine catalyst and a blowing agent comprising formic acid. The ratio of iso to epoxy groups is (pref.) 3:1 to 15:1. The resulting materials are post-cured at 200°C. The foams contain no, or very little, urethane or urea groups and are said to be especially useful in laminates a.o.  In the examples foams with densities of 25-35 kg/m³ with a thermal conductivity as low as 20 mW/mK are shown.

Bisphenol-F diglycidylether

Bisphenol-F diglycidylether

1K Dual Cure Polyurethane Adhesive

Patent Title: DUAL CURE 1K PU ADHESIVE FORMULATIONS USING MATRIX ENCAPSULATED POLYAMINES

 Number/Link: W02016022346

Applicant/Assignee: Dow

Publication date: 11-02-2016

Gist”: Encapsulated polyamines are added to a moisture curing adhesive

Why it is interesting: One component (1K) PU adhesives are either NCO-ended prepolymers cured by atmospheric moisture, or OH-ended prepolymers containing encapuslated or blocked isocyanates and which are cured by heat.  According to this invention a 1K adhesive curable by both moisture and heat can be made by incorporating an encapuslated polyamine into a 1K mositure curing prepolymer. The amine is solid at room temperature (e.g. 1,12-dodecanediamine) and is mixed with a (semi-)crystalline termoplastic with a well defined melting point, e.g. a polyacrylate or polyolefine before being added to the adhesive. Dual cure 1K adhesives allow for heat-curing the adhesive at critical spots to providing stability to an assembly.  The adhesives are said to be especially useful for the automotive industry.

1,12-dodecanediamine

1,12-dodecanediamine

 

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).

Medium density fibreboard (MDF).

PU Rigid Foams with very Small Cell Size

Title: RIGID POLYURETHANE FOAM HAVING A SMALL CELL SIZE

 Number/Link: WO2015/109488

Applicant/Assignee: Dow

Publication date: 30-07-2015

Gist”: Rigid foams are blown with CO2 under pressure

Why it is interesting: It is known that the thermal conductivity of conventional rigid polyurethane foams can be most efficiently improved by reducing the conductivity contribution of the gas present in the foam cells. This, in turn, can be achieved by reducing the gas pressure, by using ‘heavy’ blowing agents or by reducing the average cell size.  The current application discloses rigid PU foams having cell sizes small enough to achieve a thermal conductivity of less than 16 mW/m.K without the need for a strong vacuum or special blowing agents. This is achieved by first saturating the polyol formulation with CO2 under pressure, then adding the isocyanate and increasing the pressure for a set amount of time and finally releasing the pressure to allow the material to expand. Examples are given using a pressure of 7 MPa at 40°C for 30 minutes to saturate the polyol, and a pressure of 10 MPa for up to about 10 minutes after addition of the isocyanate.  Foams with average cell sizes of 8 to 70 μm and porosities of up to 90% are obtained at densities of about 250 to about 300 kg/m³.  Oddly enough no thermal conductivity (λ) values are given.

Rigid polyurethane insulation foams (Wikimedia)

Rigid polyurethane insulation foams (Wikimedia)