Low-friction fluorinated coatings

Patent metadata

Field	Value
Publication number	US-2016201005-A1
Application number	US-201615073615-A
Country	US
Kind code	A1
Filing date	Mar 17, 2016
Priority date	Mar 14, 2014
Publication date	Jul 14, 2016
Grant date	—

Abstract

Low-friction fluorinated coatings are disclosed herein. A preferred low-friction material contains a low-surface-energy fluoropolymer having a surface energy between about 5 mJ/m 2 to about 50 mJ/m 2 , and a hygroscopic material that is covalently connected to the fluoropolymer in a triblock copolymer, such as PEG-PFPE-PEG. The material forms a lubricating surface layer in the presence of humidity. An exemplary copolymer comprises fluoropolymers with average molecular weight from 500 g/mol to 20,000 g/mol, wherein the fluoropolymers are (α,ω)-hydroxyl-terminated and/or (α,ω)-amine-terminated, and wherein the fluoropolymers are present in the triblock structure T-(CH 2 —CH 2 —O)—CH 2 —CF 2 —O—(CF 2 —CF 2 —O) m (CF 2 —O) n —CF 2 —CH 2 —(O—CH 2 —CH 2 ) p -T where T is a hydroxyl or amine terminal group, p=1 to 50, m=1 to 100, and n=1 to 100. The copolymer also contains isocyanate species and polyol or polyamine chain extenders or crosslinkers possessing a functionality of preferably 3 or greater. These durable, solvent-resistant, and transparent coatings reduce insect debris following impact.

First claim

What is claimed is:

1 . A copolymer composition comprising:
(a) fluoropolymers having an average molecular weight from about 500 g/mol to about 20,000 g/mol, wherein said fluoropolymers are (α,ω)-hydroxyl-terminated and/or (α,ω)-amine-terminated, and wherein said fluoropolymers are present in the triblock structure:

wherein:
X, Y═CH 2 —(O—CH 2 —CH 2 ) p -T, and X and Y are independently selected;
p=1 to 50;
T is a hydroxyl or amine terminal group;
m=1 to 100; and
n=1 to 100;
(b) one or more isocyanate species possessing an average isocyanate functionality of about 2 or greater, or a reacted form thereof; and
(c) one or more polyol or polyamine chain extenders or crosslinkers possessing an average functionality of about 3 or greater, or a reacted form thereof.

2 . The copolymer composition of claim 1 , wherein said fluoropolymers have an average molecular weight from about 1,000 g/mol to about 10,000 g/mol.

3 . The copolymer composition of claim 1 , wherein X and Y are the same.

4 . The copolymer composition of claim 1 , wherein X and Y are different.

5 . The copolymer composition of claim 1 , wherein p is selected from 6 to 50 for each of X and Y.

6 . The copolymer composition of claim 5 , wherein p is selected from 10 to 20 for each of X and Y.

7 . The copolymer composition of claim 1 , wherein said isocyanate species are selected from the group consisting of 4,4′-methylenebis(cyclohexyl isocyanate), hexamethylene diisocyanate, cycloalkyl-based diisocyanates, tolylene-2,4-diisocyanate, 4,4′-methylenebis(phenyl isocyanate), isophorone diisocyanate, and combinations or derivatives thereof.

8 . The copolymer composition of claim 1 , wherein said polyol or polyamine chain extenders or crosslinkers are selected from the group consisting of glycerol, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, pentaerythritol, N,N,N′,N′-tetrakis(2-hydroxypropyl) ethylenediamine, and homologues, derivatives, or combinations thereof.

9 . The copolymer composition of claim 1 , wherein said composition contains, in a hard segment, said reacted form of said one or more isocyanate species, combined with said reacted form of said one or more polyol or polyamine chain extenders or crosslinkers.

10 . The copolymer composition of claim 1 , wherein said copolymer composition is present in a coating.

11 . The copolymer composition of claim 10 , wherein said coating is characterized by a coefficient of friction less than 0.5.

12 . The copolymer composition of claim 10 , wherein said coating is optically transparent.

13 . A low-friction material comprising:
a substantially continuous matrix containing a first component; and a plurality of inclusions containing a second component, wherein said inclusions are dispersed within said matrix; wherein one of said first component or said second component is a low-surface-energy fluoropolymer having a surface energy between about 5 mJ/m 2 to about 50 mJ/m 2 , and the other of said first component or said second component is a hygroscopic material that is covalently connected to said fluoropolymer in a triblock copolymer, and wherein said material forms a lubricating surface layer in the presence of humidity.

14 . The low-friction material of claim 13 , wherein said fluoropolymer is selected from the group consisting of polyfluoroethers, perfluoropolyethers, polyfluoroacrylates, polyfluorosiloxanes, and combinations thereof.

15 . The low-friction material of claim 13 , wherein said hygroscopic material is selected from the group consisting of poly(acrylic acid), poly(ethylene glycol), poly(2-hydroxyethyl methacrylate), poly(vinyl imidazole), poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline), poly(vinylpyrolidone), cellulose, modified cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, hydrogels, PEG diacryalate, monoacrylate, and combinations thereof.

16 . The low-friction material of claim 13 , wherein said fluoropolymer is perfluoropolyether and wherein said hygroscopic material is poly(ethylene glycol).

17 . The low-friction material of claim 16 , wherein said triblock copolymer is

wherein:
X, Y═CH 2 —(O—CH 2 —CH 2 ) p -T, and X and Y are independently selected;
p=6 to 50;
T is a hydroxyl or amine terminal group;
m=1 to 100; and
n=1 to 100.

18 . The low-friction material of claim 13 , wherein said continuous matrix further contains (i) one or more isocyanate species possessing an average isocyanate functionality of about 2 or greater, or a reacted form thereof; and (ii) one or more polyol or polyamine chain extenders or crosslinkers possessing an average functionality of about 2 or greater, or a reacted form thereof.

19 . The low-friction material of claim 18 , wherein said isocyanate species are selected from the group consisting of 4,4′-methylenebis(cyclohexyl isocyanate), hexamethylene diisocyanate, cycloalkyl-based diisocyanates, tolylene-2,4-diisocyanate, 4,4′-methylenebis(phenyl isocyanate), isophorone diisocyanate, and combinations or derivatives thereof.

20 . The low-friction material of claim 18 , wherein said polyol or polyamine chain extenders or crosslinkers are selected from the group consisting of 1,3-butanediol, 1,4-butanediol, 1,3-propanediol, 1,2-ethanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, ethanol amine, diethanol amine, methyldiethanolamine, phenyldiethanolamine, glycerol, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, pentaerythritol, ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, diethyltoluenediamine, dimethylthiotoluenediamine, isophoronediamine, diaminocyclohexane, N,N,N′,N′-tetrakis(2-hydroxypropyl) ethylenediamine, and homologues, derivatives, or combinations thereof.

21 . The low-friction material of claim 18 , wherein said one or more polyol or polyamine chain extenders or crosslinkers possess an average functionality of about 3 or greater, and wherein said triblock copolymer is

wherein:
X, Y═CH 2 —(O—CH 2 —CH 2 ) p -T, and X and Y are independently selected;
p=1 to 50;
T is a hydroxyl or amine terminal group;
m=1 to 100; and
n=1 to 100.

22 . The low-friction material of claim 13 , wherein said low-surface-energy polymer and/or said hygroscopic material is surface-treated.

23 . The low-friction material of claim 13 , said material further comprising one or more additional components selected from the group consisting of a particulate filler, a pigment, a dye, a plasticizer, a flame retardant, a flattening agent, and a substrate adhesion promoter.

24 . The low-friction material of claim 23 , wherein said particulate filler is selected from the group consisting of silica, alumina, silicates, talc, aluminosilicates, barium sulfate, mica, diatomite, calcium carbonate, calcium sulfate, carbon, wollastonite, and combinations thereof and where

Assignees

• Hrl Lab Llc

Inventors

• Nowak Andrew P
• Gross Adam F
• Sherman Elena

Classifications

• C10N2050/02

  dissolved or suspended in a carrier which subsequently evaporates to leave a lubricant coating · CPC title

• C10N2020/04

  Molecular weight; Molecular weight distribution · CPC title

• C10N2030/06

  Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure · CPC title

• C10N2030/04

  Detergent property or dispersant property · CPC title

• C10M2201/084

  containing sulfur, selenium or tellurium · CPC title