Low foaming hydraulic fluids having biodegradable polyalkylene glycol rheology modifiers useful in subsea applications

Patent metadata

Field	Value
Publication number	US-12473399-B2
Application number	US-202118007077-A
Country	US
Kind code	B2
Filing date	Sep 22, 2021
Priority date	Sep 30, 2020
Publication date	Nov 18, 2025
Grant date	Nov 18, 2025

Abstract

A composition comprising water and a polyalkylene glycol having an allyl content of less than 20 μeq/g, which composition has reduced foaming properties and preferably a biodegradability of at least 60% as determined using OECD 301F. The polyalkylene glycol can be made by forming a first intermediate comprising an oxypropylene block by reacting propylene oxide with a polyol initiator in the presence of a Double Metal Cyanide catalyst, and then reacting the first intermediate with ethylene oxide in the presence of a KOH catalyst.

First claim

The invention claimed is:

1 . An aqueous composition comprising a polyalkylene glycol block copolymer wherein the polyalkylene glycol has a molecular weight of no more than 4000 g/mol and is characterized in that it is an oxyethylene/oxypropylene block copolymer having a weight percent of oxyethylene of at least 20% based on total weight of the copolymer and an allyl content of less than 20 μeq/g.

2 . The composition of claim 1 characterized by exhibiting an initial foam height of less than 50 ml at 0.5% by weight concentration in deionized water and less than 15 ml after 5 minutes as determined according to ASTM D1173 at ambient temperature.

3 . The composition of claim 1 wherein the polyalkylene glycol block copolymer has a biodegradability of at least 60% as determined using OECD 301F.

4 . The composition of claim 1 further comprising a glycol, wherein the glycol is selected from ethylene glycol and diethylene glycol.

5 . The composition of claim 1 wherein the block copolymer has a triblock structure with two oxyethylene blocks on either side of an oxypropylene block.

6 . The composition of claim 1 wherein the weight percent of oxyethylene in the polyalkylene glycol is less than 40%.

7 . The composition of claim 1 wherein the water is present in an amount of 10 to 60 percent by weight.

8 . The composition of claim 1 further comprising one or more additives selected from corrosion inhibitors, friction modifiers, anti-wear additives, air release additives, foam control agents, anti-microbials and dyes.

9 . The composition of claim 1 wherein the polyalkylene glycol has the formula

wherein a′ and a″ are independently in each occurrence an integer of 1 to 20 provided that a′+a″ is at least 5 and no more than 40, and b is an integer of from 15 to 40.

Assignees

• Dow Global Technologies Llc

Inventors

• Greaves Martin R
• Kersbulck Jochem

Classifications

• C08G65/269

  Mixed catalyst systems, i.e. containing more than one reactive component or catalysts formed in-situ · CPC title

• C10N2020/02

  Viscosity; Viscosity index · CPC title

• C10M2209/1045

  used as base material · CPC title

• C10N2040/04

  Oil-bath; Gear-boxes; Automatic transmissions; Traction drives · CPC title

• C10M2209/104

  of alkylene oxides containing two carbon atoms only · CPC title