Polyurethane for Oil Well Refracking

Patent Title: METHODS AND MATERIALS FOR REFRACTURING A PARTIALLY DEPLETED OIL AND GAS WELL

Number/Link: US2018/0346786

Applicant/Assignee:  Covestro

Publication Date: 6 December 2018

“Gist”: Use of low-reactive, low-viscosity PU systems for oil well sealing

Why it is interesting: It is known that partially depleted fracking wells can be “re-fractured” to increase production. Prior to this operation former perforations in the well casing need to be sealed to prevent furthering of existing fractures, by using a chemical “diverting agent”.  According to this invention, the diverting agent can be a polyurethane system with a long potlife and relatively low viscosity, which is prepared from an unblocked hexamethylene diisocyanate and a polypropyleneoxide triol which is miscible with the isocyanate. In the examples an allophanate-modified HDI is used together with a 450-molecular weight PO triol and a delayed-action tert amine catalyst. The system does not de-mix and has a gel time ranging from 30 to more than 1000 minutes.

refracking

Sealing of fracking well

 

 

Novel i-PEEP Polymers

Patent Title:  ISOCYANATE-MODIFIED POLYESTER-EPOXIDE POLYMER COMPOSITIONS

 Number/Link: WO2018/160217

Applicant/Assignee:  Stepan

Publication date: 7 September 2018

“Gist”: Polyester polyols are reacted with isocyanates and polyepoxies

Why it is interesting: The invention is related to isocyanate-modified polyester-epoxy polymers (i-PEEPs) which are said to be a “new class of polymers” useful as adhesives, coatings and elastomers.  The materials are prepared by reacting polyester polyols with both polyisocyanates and polyepoxies at an “i-PEEP index” (=(eqvs iso + eqvs epoxy)/eqvs polyol in %) of 100 to 200. The reaction can be run catalysed at room temperature or optionally un-catalyzed at 40 to 100°C. In the examples aromatic and aliphatic polyester polyols are reacted with polymeric MDI and BPA-DGE – based polyepoxide at different indices to produce elastomers with shore A hardness ranging between 30 and 95.
Interesting materials, although calling them a new class of polymers may be a bit exaggerated.

Bisphenol_A_diglycidyl_ether_200

Bisphenol-A diglycidylether (BPA-DGE)

 

PU Elastomers from SGO Polymerized Acrylic Polyols

Patent Title: PHYSICAL PROPERTY IMPROVEMENT OF POLYURETHANES

 Number/Link: WO2018/132648

Applicant/Assignee:  BASF

Publication date: 19 July 2018

Gist”: Solvent-free acrylate polyols are reacted together with polyether polyols and diisocyanates

Why it is interesting: In this invention a solvent-free (“100% solids” in the patent’s terminology) acrylic polyol is blended with a conventional polyether polyol and reacted with an aliphatic or aromatic diisocyanate.  The acrylic polyol is prepared by co-polymerizing (e.g.)  ethyl- or butyl (meth)acrylates, styrene and a hydroxyl functional acrylate like 2-hydroxyethyl acrylate or 4-hydroxybutyl acrylate, using BASF’s “solid grade oligomer” (SGO) polymerization process. The SGO process is a high temperature and high pressure continuous process allowing for the production of low-solvent acrylic resins. The polyurethanes are said to have increased physical properties, esp. tear- and tensile strength properties.

HBA

Hydroxybutylacrylate

Hybrid Polyisocyanurates for Composites and Coatings

Patent Title: DUAL-CURING ISOCYANURATE POLYMERS

 Number/Link:WO2018/087395 WO2018/087396  WO2018/087399 (German)

Applicant/Assignee:  Covestro

Publication date: 17 May 2018

Gist”:  Di-isocyanate trimer is reacted with hydroxymethacrylates and polyacrylates in the presence of a trimerization catalyst. 

Why it is interesting: According to these inventions a reaction system with two curing modes can be prepared by mixing high functionality oligomeric isocyanate, ethylenically unsaturated compounds, unsaturated compounds containing isocyanate-reactive groups, timerization catalyst and a free-radical initiator at an NCO index of 100 to 200. The system shows a relatively low viscosity and can e.g. be used in fiber-reinforced composites and in coatings. In the examples HDI trimer is reacted with hexanedioldimethacrylate and hydroxypropylmethacrylate in the presence of potassium acetate and a peroxybenzoic acid.

HDI isocyanurate

HDI-trimer


Photocrosslinkable Polyurethane Coatings and Adhesives

Patent Title: PHOTORESPONSIVE POLYURETHANES

 Number/Link: WO2018/039453

Applicant/Assignee:  Univ of Akron

Publication date: 1-March-2018

Gist”: PU coatings or adhesives with built-in coumarin or phenacyl groups 

Why it is interesting: According to this invention, polyurethane coating- and adhesive systems with two ‘levels of strength’ can be made by incorporating photoresponsive groups like coumarin into the PU backbone.  The coumarin groups will dimerize when irradiated with UV light of about 340nm and can be cleaved again with light of about 250nm. Alkoxyphenacyl groups can also be built into the PU backbone, allowing photocleavage with UV light of 250-350nm. The use of coumarin in (self-healing) coatings is not new and has been discussed before in this blog, so I doubt that this is patentable.

coumarin monomer

Hydroxy functional coumarin monomer