Patent ID: 11927919
Assignee: PATEK PHILIPPE SA GENEVE
Field: Basic materials chemistry (Chemistry)
Classification: CPC G  B  C | IPC C  G

Claim 19:
20. A timepiece assembly comprising at least two elements in contact and mobile relative to each other, one of said elements having at least a first contact surface intended to rub against at least a second contact surface of the other element under dry lubrication conditions, wherein at least one of said first and second contact surfaces is covered with a hydrophobic coating having an angle of contact with water greater than 90°, and a coefficient of friction lower than 0.15, the variation in said coefficient of friction as a function of the relative humidity being lower than 25%,
wherein the hydrophobic coating is bonded to one of said first and second contact surfaces at least by covalent bonds,
wherein the hydrophobic coating comprises at least a first layer formed by at least one assembly of molecules comprising a head, a separation chain and a terminal group, at least a part of the heads of the molecules being bonded to said one of the first and second contact surfaces by covalent bonds, and the separation chains being arranged substantially parallel to each other and orientated substantially perpendicular to said one of the first and second contact surfaces, and
wherein the hydrophobic coating comprises at least a first layer and second layer,
wherein the second layer comprises molecules having a head bonded to the terminal group of the molecule of the first layer, a separation chain and a non-polar terminal group, the separation chains being arranged substantially parallel to each other and orientated substantially perpendicularly to said one of the first and second contact surfaces.