Polyurethane elastomeric seal for hydraulic pumps

Patent metadata

Field	Value
Publication number	US-9664282-B2
Application number	US-201414897720-A
Country	US
Kind code	B2
Filing date	Aug 14, 2014
Priority date	Aug 20, 2013
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A method for forming a piston seal of a hydraulic pump includes forming a reaction mixture that includes a prepolymer component, a polyol additive, a diol component, and a curative component, forming a sealing element with the reaction mixture and a mold, and curing the sealing element to form a piston seal of a hydraulic pump. The prepolymer component includes a polycarbonate-isocyanate prepolymer that is a reaction product of at least an isocyanate component and a polycarbonate polyol component.

First claim

The invention claimed is:

1. A method for forming a piston seal of a hydraulic pump, the method comprising:
forming a reaction mixture that includes a prepolymer component, a polyol additive, a diol component, and a curative component, wherein:
the prepolymer component includes a polycarbonate-isocyanate prepolymer that is a reaction product of at least an isocyanate component and a polycarbonate polyol component, and the prepolymer component is present in an amount from 55 wt % to 90 wt %, based on a total weight of the reaction mixture,
the polyol additive includes a polycarbonate polyol, which is present in an amount from 5 wt % to 40 wt %, based on the total weight of the reaction mixture,
the diol component is present in an amount from 5 wt % to 20 wt %, based on the total weight of the reaction mixture, and
the curative component includes a diamine based curative agent that is present in an amount from 0.01 wt % to 20 wt %, based on the total weight of the reaction mixture,

forming a sealing element with the reaction mixture and a mold, and
curing the sealing element to form a piston seal of a hydraulic pump.

2. The method as claimed in claim 1 , wherein the polycarbonate-isocyanate prepolymer is the reaction product of a mixture in which the polycarbonate polyol component is present in an amount from 30 wt % to 80 wt % and the isocyanate component is present in an amount from 20 wt % to 60 wt %, based on a total weight of the mixture.

3. The method as claimed in claim 1 , wherein the polycarbonate polyol component includes a polycarbonate diol, and the polycarbonate-isocyanate prepolymer is the reaction product of a mixture in which the polycarbonate diol is present in an amount from 55 wt % to 70 wt % and the isocyanate component is present in an amount from 30 wt % to 45 wt %, based on a total weight of the mixture.

4. The method as claimed in claim 1 , wherein the amount of the curative component in the reaction mixture in from 0.01 wt % to 4.5 wt %, based on the total weight of the reaction mixture.

5. The method as claimed in claim 4 , wherein the curative component includes at least one selected from the group of a toluene based diamine curative agent and a chlorinated aromatic diamine curative agent.

6. The method as claimed in claim 1 , wherein the isocyanate component includes at least 60 wt % of 4,4′-methylene diphenyl isocyanate and a remainder of 2,4′-methylene diphenyl isocyanate, based on a total of 100 wt % for the isocyanate component.

7. The method as claimed in claim 1 , wherein after the sealing element is cured to form the piston seal of the hydraulic pump, the piston seal is attached to a piston of the hydraulic pump.

8. The method as claimed in claim 1 , wherein the sealing layer is formed on a piston of the hydraulic pump and the sealing layer is cured in place on the piston.

9. The method as claimed in claim 1 , wherein the hydraulic pump is a concrete pump.

10. A hydraulic pump that includes a piston seal formed according to the method claimed in claim 1 .

Assignees

• Dow Global Technologies Llc

Inventors

• Duggal Rajat
• Jagtap Subodh P

Classifications

• C08G18/44

  Polycarbonates · CPC title

• F04B53/143

  Sealing provided on the piston · CPC title

• F04B53/02

  Packing the free space between cylinders and pistons · CPC title

• F16J9/28

  of non-metals · CPC title

• F04B53/14

  Pistons, piston-rods or piston-rod connections · CPC title