Syntactic polyurethane elastomers based on low unsaturation polyols for use in subsea pipeline insulation

Patent metadata

Field	Value
Publication number	US-10301481-B2
Application number	US-201415025167-A
Country	US
Kind code	B2
Filing date	Oct 21, 2014
Priority date	Oct 30, 2013
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

Syntactic polyurethane elastomers are made using a non-mercury catalyst. The elastomer is made from a reaction mixture containing a polyether polyol having a low amount of terminal unsaturation, a chain extender, a polyisocyanate and microspheres. The elastomer adheres well to itself, which makes it very useful as thermal insulation for pipelines and other structures that have a complex geometry.

First claim

What is claimed is:

1. A process for producing a substrate having an applied syntactic polyurethane elastomer, comprising the steps of
a) forming a first section of syntactic polyurethane elastomer on at least a portion of the substrate by (i) applying a first reaction mixture containing at least one polyether polyol having a number average hydroxyl equivalent weight of at least 800 wherein the polyether polyol(s) contain no more than 60 μeq/g of terminal unsaturation, 5 to 50 weight percent of microspheres based on the total weight of the reaction mixture, 1 to 30 parts by weight of a hydroxyl-terminated chain extender per 100 parts by weight of the polyether polyol(s), an aromatic polyisocyanate in amount to provide an isocyanate index of 80 to 130, 0.1 to 0.25 wt. % of a β-diketone compound based one the combined weight of all components of the reaction mixture except the aromatic polyisocyanate and a non-mercury catalyst to at least a portion of the surface of the substrate and (ii) partially curing the first reaction mixture to maintain its shape to form the first section of syntactic polyurethane elastomer, and then
b) forming a second section of syntactic polyurethane elastomer on at least a portion of the substrate by (i) applying a second reaction mixture containing at least one polyether polyol having a number average hydroxyl equivalent weight of at least 1000 wherein the polyether polyol(s) contain no more than 60 μeq/g of terminal unsaturation, 5 to 50 weight percent of microspheres based on the total weight of the reaction mixture, 1 to 30 parts by weight of a hydroxyl-terminated chain extender per 100 parts by weight of the polyether polyol(s), an aromatic polyisocyanate in amount to provide an isocyanate index of 80 to 130, 0.1 to 0.25 wt % of a β-diketone compound based one the combined weight of all components of the reaction mixture except the aromatic polyisocyanate and a nonmercury catalyst to at least a portion of the surface of the substrate and in contact with the first section of syntactic polyurethane elastomer to form at least one bondline between the first section of syntactic polyurethane elastomer and the second reaction mixture and (ii) at least partially curing the second reaction mixture to form the second section of syntactic polyurethane elastomer adherent to the first section of syntactic polyurethane elastomer, wherein the bondline has a bond strength of at least 8.0 MPa, as measured according to ASTM D638.

2. The process of claim 1 wherein the reaction mixtures are devoid of mercury compounds.

3. The process of claim 1 wherein the substrate is an undersea pipe or undersea architecture.

4. The process of claim 3 wherein the undersea pipe or undersea architecture is branched, curved or has another non-linear configuration.

5. The process of claim 3 wherein the undersea pipe or undersea architecture has one or more external features that protrude partially or completely through the applied syntactic polyurethane elastomer.

6. The process of claim 1 , wherein the β-diketone is a compound having the structure:

wherein each R is independently hydrocarbyl or inertly substituted hydrocarbyl.

7. The process of claim 1 , wherein the β-diketone compound is one or more of acetylacetone (pentane-2,4-dione), hexane-2,4-dione, heptane-3,5-dione and 2,2,6,6-tetramethyl- 3,5-heptanedione.

8. The process of claim 1 , wherein the non-mercury catalyst is one or more metal catalyst(s), and the weight of the β-diketone compound 2 to 5 times that of the metal non-mercury catalyst(s).

9. The process of claim 1 , wherein the polyether polyol(s) is in each instance (A) prepared by adding propylene oxide and ethylene oxide to a difunctional or trifunctional initiator to produce a polyol having a hydroxyl equivalent weight of 1500 to 2500 and containing 5 to 30% by weight polymerized ethylene oxide, based on total product weight, wherein the polymerized ethylene oxide is randomly polymerized with the propylene oxide, forms one or more internal blocks and/or forms terminal blocks that result in primary hydroxyl groups or (B) made by homopolymerizing propylene oxide or randomly copolymerizing 75-99.9 weight percent propylene oxide and 0.1 to 25 weight percent ethylene oxide onto a trifunctional initiator, and optionally capping the resulting polyether with up to 30% by weight based on total product weight ethylene oxide to form a polyether polyol having an equivalent weight of 1500 to 2500.

10. The process of claim 1 wherein the non-mercury catalyst is a zinc carboxylate or a mixture of 98-99.99 wt % of a zinc carboxylate catalyst and 0.01 to 2 wt % of one or more zirconium carboxylates.

Assignees

• Dow Global Technologies Llc

Inventors

• Gelfer Mikhail Y
• Stephenson Amber
• Minnikanti Venkat S
• Brown Ii Mark
• Vyakaranam Kamesh

Classifications

• C08J2375/08

  from polyethers · CPC title

• C08G18/3206

  aliphatic · CPC title

• C08G18/4841

  containing oxyethylene end groups · CPC title

• C08G18/485

  containing mixed oxyethylene-oxypropylene or oxyethylene-higher oxyalkylene end groups · CPC title

• C08J9/32

  from compositions containing microballoons, e.g. syntactic foams · CPC title