WO2016016019A1

WO2016016019A1 - Timepiece component with a surface comprising silk fibroin

Info

Publication number: WO2016016019A1
Application number: PCT/EP2015/066403
Authority: WO
Inventors: Xavier LANDREAU; Xavier RIOU
Original assignee: Cartier International Ag
Priority date: 2014-08-01
Filing date: 2015-07-17
Publication date: 2016-02-04
Also published as: CN107077095B; EP3175303B1; EP3175303A1; JP2017522572A; JP6567038B2; CN107077095A

Abstract

The present invention concerns a component having a surface subjected to friction, wherein at least a portion of said surface is formed from a material comprising fibroin. The fibroin can be applied as a thin layer to the surface, or the component itself can comprise a composite material incorporating fibroin in a suitable matrix. Moreover, the invention also concerns components formed entirely from fibroin.

Description

Watchmaking component with a surface comprising silk fibroin

Technical area

The present invention relates to a component of a watch movement undergoing friction and requiring good tribological properties. In particular, but not exclusively, the present invention is directed to a bearing, a cog, an exhaust, or a watch motor spring.

State of the art

In the field of microtechnology, which will subsequently be more particularly illustrated by the watch industry, it is known to lubricate

components that have surfaces that are subject to friction. Lubrication is generally obtained by the application of oils or greases, generally based on hydrocarbons, fluorocarbons or silicones. This solution is not however free from disadvantages.

[0003] Oils and fats in particular undergo degradation of their lubricating power over time, due to chemical alterations and contaminations, so that any movement lubricated by these means must be periodically disassembled, cleaned and newly lubricated.

In the field of microtechnology and especially in the field of watchmaking, there is a need for structural materials that can replace steel, nickel silver or metals normally used while having a lower density. Such a material would in particular improve the energy efficiency of mechanical devices, including escapements and watch movements.

Known watch movements that use for this purpose elements made of technical polymers, for example the PEEK (Polyetheretherketone). These achievements, however, do not achieve the durability and reliability of traditional metal components.

Silk is a well-known natural fiber produced by the larvae of the butterfly Bombyx mori, which is traditionally used in the form of threads and fabrics for thousands of years.

The mechanical properties of the silk are due to a protein called fibroin which forms the center of the wire. Fibroin is a highly insoluble protein that is predominantly (up to 90%) composed of the amino acids glycine, alanine, and serine, and has an extremely high fibrous structure and mechanical strength. There are also other natural fibers produced by insects or arachnids which, while much less used, also contain fibroin and are known by their mechanical qualities. The present invention relates to a watch component with fibroin from any natural or artificial source. Embodiments of the invention may include, but are not limited to, fibroin obtained from cocoons of Bombyx mori or other lepidopteran larvae, spiders, bacteria, yeasts, molds, cell cultures. In the context of the invention, fibroin can be obtained from genetically modified organisms. [0008] The unique properties of fibroin have been the subject of much attention, particularly in the medical industry. WO2014011644, for example, provides methods for the production of pure fibroin, and its use as a biocompatible material and in drugs.

WO2013163407 describes for example the production of fibroin microspheres with a low coefficient of dry friction, this however for a medical application: the treatment of joint pain. For example, WO2012145594 proposes molding shaping to produce implantable devices capable of integrating with living tissues.

The patent application JP11042106 describes a painting comprising silk particles. The paint is applied to the surface of a watch so that the surface is pleasant to the touch. Brief summary of the invention

An object of the present invention is to provide components usable in a watch movement free of the limitations of known components, particularly in connection with lubrication and properties.

tribological. The present invention relates to a component having a surface undergoing friction of which at least a portion of this surface is formed of a material comprising fibroin.

The fibroin may be applied as a thin layer to the surface of the component, or the component itself may comprise a composite material incorporating fibroin into a suitable matrix. Moreover, the invention also relates to components integrally made of fibroin.

In the context of the invention fibroin can be used in the pure state, or in combination with functional additives to improve its performance, for example plasticizers, adhesives, lubricants, the latter for example containing mineral oils, glycerol, lipids, solid lubricants or any other suitable lubricating substance, pigments, and so on.

As regards the elements made, the invention can be applied to all components of the watch that are moving or that are subject to friction. By way of example, mention may be made of the wheels, and in particular the working surfaces of the gears; the stones or simple bearings and the axes of mobiles which are housed there; the exhaust members comprising the teeth of the escape wheel, the pallets, the fork and the stinger of the anchor, the ankle and the balance plate; the mainspring and the barrel. This list and however far from exhaustive. Brief description of the figures

Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which:

Figure 1 illustrating a watch exhaust system according to one embodiment; and

Figure 2 showing a bridge of a watch, according to one embodiment.

Example (s) of embodiment of the invention

The invention will now be described with reference to the components for watch movement shown in Figures 1 and 2. To simplify the description, this example specifically refers to a system

exhaust, but it should be understood that the invention is not limited to this specific embodiment and includes any watch component subjected to friction.

In the example shown in Figure 1, we can see an exhaust system 1 for a timepiece. The exhaust system 1 comprises in particular an escape wheel 3, comprising an escape wheel secured to an exhaust pinion, pivotally mounted on an axle 30, an anchor 2 pivotally mounted on an anchor rod 23, and a plate 4 driven on a balance shaft 40. The plate 4 comprises a small plate 41 provided with a notch 42 and a large plate 43 provided with a pin (not shown in Figure 1). The anchor 2 comprises arms 21 comprising lifts 22 cooperating with teeth 31 of the escape wheel 3. At the end opposite the arms 21, the rod 20 comprises a dart 24 and a fork 25. The dart 24 is intended to cooperate with the small plate 41 to prevent accidental movements of the fork 25. The fork 25 is preferably mounted directly above the dart 24 and comprises two horns 26 intended to come into contact with the large plate pin 43 so, following the rotation of the pin, to cause the anchor 2 pivoting about its rod 23 in a back and forth motion. The exhaust systems are difficult to develop because they are the compromise between the lowest possible inertia and the best possible tribological properties, in particular, lifts 22 and the range 25. Thus, it is difficult avoid collars between the plateau pin and the horns 26 of the fork 25 while preserving minimal inertia and even insensitivity to magnetic fields.

According to one aspect of the invention, the mobiles are coated at least partially with a layer comprising fibroin in order to favorably modify their tribology. The layer comprising the fibroin may be a solid layer, for example deposited by evaporation of aqueous solutions of fibroin, or a liquid or colloidal layer, in which fibroin particles are suspended in a liquid matrix or gel.

Advantageously, the fibroin layer comprises additives to improve the tribological characteristics, for example lubricants, glycerol, plasticizers, adhesives, pigments, or substances whose purpose is to inhibit the degradation of the body. fibroin.

According to another aspect of the invention, the fibroin may be a functional component of a composite material, in a solid matrix composed for example by a resin. In a variant of this aspect, the composite material may have a fibroin matrix and also reinforcements made of fibroin material of another form.

When the fibroin is in the form of dispersed particles, in a solid matrix, liquid or gel, they may be microspheres, needles, fibers, or grains or particles of any shape. According to another variant, the watch component of the invention can be made from a solid monolithic block comprising fibroin as a main or secondary ingredient. Such a block can be made for example by fusing powders of fibroin material under high temperatures and pressures. The component of the invention may also be covered, in variants, by a tissue or an entanglement of fibroin fibers,

optionally with additives.

In one possible embodiment, the entire surface of the component may be coated with the layer containing fibroin. However, it may be considered to cover only a portion of the mobile. For example, the anchor 2 may be coated only at the fork 25 and the lifts 22. In this configuration, the fork 25 and the lifts 22 have a low wear and a low coefficient of friction in association with the ankle. In another example, the escape wheel 3 can be coated at the teeth 31. Similarly, the plate 4 can be coated with the layer

comprising fibroin only at the level of the large plateau ankle 43.

When the invention comprises a thin layer of fibroin, the substrate on which the layer is deposited can be made according to the techniques and materials commonly used in watchmaking, for example steel, brass, nickel silver, gold, titanium. If, on the other hand, fibroin is used as a solid block, or as a functional component (reinforcement and / or matrix) of a composite material, the component of the invention will be entirely made of this material, or will comprise a part made of a material containing fibroin.

In one embodiment, the component whose surface contains fibroin is used for the manufacture of fixed watch components but undergoing friction. Such components may comprise the frame of the watch, for example, the plate and / or the bridges, serving as a support for other movable members (not shown in Figure 2) of the watch. As an illustration, Figure 2 shows a bridge 50 of a watch. The component 50 may be made of steel, brass, nickel silver, titanium, or any other suitable material.

Still according to the invention, the component 50 may be coated at least partially with a layer comprising fibroin in order to modify the tribology and / or the characteristics of resistance to friction. For example, the layer may coat the portion supporting the mobile, in particular the portion 52 of the component where the pivot of the mobile comes to hunt. More particularly, the wall of the hole 51 forming a bearing may be coated with the layer comprising fibroin thereby decreasing the coefficient of friction on the wall of the holes and improving the friction torque between the bearing and the shaft of the mobile which can itself even be coated with fibroin. In this way, it is possible to pass ruby pad (or stone) in which are normally mounted pivots.

According to a variant, the hole 51 forming a bearing is in a part made of a material containing fibroin, fixed on the bridge 50. [0030] An advantage of the component 50 according to the invention is that it makes it possible to produce plates and bridges having very small thicknesses. It therefore becomes possible to manufacture thinner watch cases. Another advantage is to be able to realize the component (frame, plate and / or bridge) in one piece with great precision while avoiding the disadvantages induced by mounting steps (stonework). The flatness and precision of the component are improved despite its small thickness.

An embodiment of the invention relates to the use, in a component for a watch movement, of a material comprising fibroin. The method for producing components in solid, coated or composite form comprises two steps: a first step of adjusting the experimental conditions for bringing the raw material to flow or to be projected to form an object; this first step involves the development of a suitable protein solution. A second step is to adjust the conditions of the raw material either to bring the raw material to a gel state, or to bring it near the sol-gel transition point.

In order to achieve dissolution of the silk fibroin, the process uses one or more solvents which may be for example aqueous solvents, fluorinated, ionic liquids or strong acids for example. However, some of the fibroin may remain insoluble and within the solution. This solid material is preferably removed from the solution, for example by centrifugation or pressure filtration.

Following the dissolution step, additives can be added. These additives may be, for example, color pigments, anti-wear inserts, polymers, fats or oils, powders, surfactants, etc. At this stage, it is also possible to mix the a first solution with a second or a multitude, so as to create a composite or to modify the chemical and physical properties of the material obtained, in order to target a particular morphology for example. After the fibroin dissolution step, comes the shaping of the material. Non-exhaustively, this shaping can take the form of capsules, spheres, fibers, foams, gelled monolithic massifs, or combinations of the above. The formatting of different

architectures described above can be performed by many processes such as molding, spinning, electrospinning, projection or precipitation (non-exhaustive), or shaped monolith by molding.

Because of its self-lubricating properties, the material developed can be advantageously substituted for liquid lubricants traditionally used in watch movements. Tests carried out on the material of the invention have revealed a dynamic coefficient of friction as low as 0.03 for contact pressures of 50 MPa when in contact with steel under conditions of relative speed of the order mm / s. This low coefficient is maintained for large friction distances (> 1km). All other conditions being equal, this coefficient of friction is lower than that measured for a diamond / diamond contact.

Compared to the wet lubrication used

conventionally in the watchmaking field. The use of dry lubrication components reduces the time required for cleaning, emptying and oiling movements while increasing the duration of their warranty. In addition to the tribological properties, the low density of the material (about 1.2 g / cm3) compared with that of steel (about 7 g / cm3) makes it possible to increase the efficiency of the transmission (by reducing the especially moments of inertia) and therefore the overall power reserve of the watch movement.

For comparison, the density and the mechanical properties of the components, and in particular their Young's modulus (about 12 GPa) and their hardness (about 30HV) are close to those of plastic components PEEK type. In contrast, the tribological properties, particularly in terms of coefficient of friction and wear, are much higher.

The developed components successfully validate the tests of resistance to chemicals and climatic watch, including synthetic sweat tests, salt spray or tropical climate.

Reference numbers used in the figures exhaust system

anchor

baguette

arms

lifting

anchor rod

sting

fork

horn

escape wheel

exhaust pinion

teeth of the escape wheel

hub

tray

balance shaft

small tray

nick

big plateau

bridge

hole

portion

Claims

claims

A component for a timepiece, having a surface undergoing friction, characterized in that at least a portion of this surface is formed of a material comprising fibroin.

2. Component according to claim 1, wherein said surface undergoing friction is one of: surface of a pivot axis mounted on a pad; bearing surface of a bearing for receiving a pivoting axle; impulse surface of an exhaust; surface of an anchor pallet; contact surface of a tooth; surface of a mainspring; internal surface of a barrel.

3. Component according to claim 1 or 2, wherein said surface is at least partially coated with at least one layer of fibroin or with a set of fibers woven or entangled with fibroin.

The component of claim 1 or 2, wherein said material is a composite material with particles and / or microspheres and / or granules and / or or fibroin fibers in a polymeric, synthetic or metallic matrix.

5. Component according to claim 1 or 2, wherein the fibroin is included in a solid matrix, in particular resin.

The component of claim 1 or 2, wherein the fibroin is gel-shaped.

The component of claim 1 or 2 comprising a solid fibroin element.

8. Component according to claim 3, wherein the coating has a thickness between 2 and 100 μιη.

9. Component according to one of claims 1 to 8 wherein the fibroma material comprises additives to improve the characteristics.

tribological.

10. Component according to one of claims 1 and 3 to 9 forming a fixed component of a watch frame serving as a support for at least one movable member.

11. Component according to one of claims 1 and 3 to 9 forming a movable member intended to be pivotally mounted on a shaft supported by a fixed component of a watchmaking frame.

12. Component according to one of claims 1 to 11 being made entirely in a material comprising fibroin.

13. Exhaust system for a watch movement, comprising a component according to one of claims 1 and 3 to 9, said component being one of the exhaust members and said surface undergoing friction belongs to one of the teeth of the escape wheel, the pallets, the fork, the anchor stinger, the ankle, the balance plate, the mainspring and the barrel.

Clock movement comprising at least one component according to one of claims 1 to 12.

15. Timepiece comprising at least one component according to one of claims 1 to 12.