Abrading – Abrading process – Utilizing fluent abradant
Reexamination Certificate
2000-10-11
2002-08-13
Eley, Timothy V. (Department: 3723)
Abrading
Abrading process
Utilizing fluent abradant
C451S038000, C451S054000, C451S055000, C427S198000, C427S205000
Reexamination Certificate
active
06431958
ABSTRACT:
The present invention relates to a novel method of mechano-chemically treating a material which enables:
on the one hand, improving, in one sole operation leading to a subsequent mechano-chemical anchoring, the surface properties of a material, such as, in particular, its aptitude to adherence during subsequent assemblings;
on the other hand, improving the surface properties of use of a material by the simple carrying out of a coating having composite structures.
This invention finds a first series of applications in every field in which it is sought to improve the interface properties of a material with a view to its use with another material, in particular during assemblings, notably during sticking together of the two materials, or during the adhesive filling of cavities.
The principal fields concerned are odontology, the biomedical field, the preparation of carried products which use microtechniques, the field of the automobile industry, and that of the avionics industry.
Within this context, the invention more particularly applies to the treatment of metallic pieces with a view to improving the coherence and the reactivity of the interface between the metal and a polymer material generally constituting glue or the coating intended to be applied thereon.
This invention finds a second series of applications in every field in which it is sought to improve the surface properties of use of a material, in particular of a material covered with a polymer, by the incorporation in this covering of fillers which are notably ceramic fillers, mineral or metallic fillers, by thus preparing composite structures the polymer covering of which constitutes the matrix.
Within this context, the invention applies more particularly to the preparation of hard non-adhesive (anti-adhesive) coverings.
The principal fields concerned are the printing industries, (textile or paper), those of agri-foodstuffs, the mechanical industries, with applications in the automobile industry.
At present, in every operation of preparation of a surface with a view to its assemblage by sticking with another surface, one proceeds in a classical manner sequentially by carrying out successively:
a mechanical treatment, by impacts of particles so as to generate a roughness intended to favour the mechanical anchoring;
and then, a chemical treatment, by successive applications, notably by daubing onto the surface, or by pulverising onto the surface thus mechanically treated, various chemical products intended to improve the properties of adhesion and of adherence of this surface.
The mechanical methods of surface treatment which are the most frequently carried out in industry or in laboratories, such as, for example, sandblasting, shot blasting, balling, etc., are based on projecting various projectiles onto the surface to be treated preferably projectiles of abrasive character. All these methods give good results while being easy to use.
The projectiles which can be used in the context of the methods mentioned above are of various nature and are generally characterised by their nature, their shape, their dimensions, their particle size, their density, their integrity.
Industrially, the most commonly used projectile is spherical or angular steel shot, round or angular cast iron shot, aluminium or copper shot, glass microballs, shot of ceramic material of the alumina or silica type.
In micro-sandblasting, for the moment, alumina or corundum grains are most frequently employed. These grains possess active ridges which guarantee a high efficiency in terms of macro- and micro-roughness of a surface.
In the particular field of odontology in which numerous operations of assembling are carried out by sticking together a metallic material and a polymer material, essentially two methods are known which aim to improve the quality of metal-polymer interfaces. These are:
on the one hand, a method developed by the company ESPE and known under the designation <<Rocatec® method>>; and
on the other, a method developed by the company KULZER and known under the designation <<Silicoater MD® method>>.
The Rocatec® method enables carrying out a sandblasting qualified as a <<reactive>> sandblasting. This method starts off with a first sandblasting by alumina grains of about 250 &mgr;m, which is followed by a second sandblasting which uses alumina grains of size which is roughly equal to that of the preceding ones but which are covered in silica micro-grains. These two types of sandblasting are followed by a step of brush-depositing a layer of silane.
This method, which comprises three steps, necessitates the purchase of a specific sandblasting unit.
The Silicoater MD® method consists essentially in carrying out a deposit of silica onto the metallic surfaces by pyrolysis. This method, which does not comprise any sandblasting operation, does nevertheless necessitate a specific piece of equipment, and in particular a heating enclosure.
Thus, the methods of surface treatment which are classically used up to present with a view to carrying out a cohesive assembling necessitate the use of specific pieces of equipment and/or are generally carried out sequentially, and this manifests itself by the relatively significant latent periods between the mechanical and chemical treatments, even between various successive chemical operations, which risk disturbing the quality of the expected results.
It is in this context that the inventors have sought developing a method of treating a material which does not necessitate any specific piece of equipment and which notably enables improving the surface properties of this material, in one sole step, during which a mechanical treatment by impacts and a chemical treatment were carried out concomitantly, or enables improving the properties of use of this material by preparing a surface covering of composite structures.
The method developed in accordance with the present invention in order to attain this objective is essentially characterised by the fact that it comprises projecting onto a material particles having stratified structure which are constituted of a core and of a coating comprising at least one polymer and optionally a chemical agent, under conditions such that said particles and/or the fragments resulting from their fracturing become encrusted in and/or penetrate into said material.
According to a first embodiment, this method is intended to improve the surface properties of a material, and in particular its adherence during its assembling with a second material, and comprises projecting particles having stratified structure onto the surface of said material, under conditions such that said particles fragment during impact and become encrusted in said material.
An anchoring is thus obtained in one sole operation, at the surface of the material to be treated, of fragments of projected particles, and, consequently, an anchoring of their coating is thus obtained, this operation being designated in the present application by the expression “mechano-chemical anchoring”.
In other words, the chemical reaction on the surface of the treated material is linked to a concomitant encrustation of the stratum or strata of the stratified particles, this encrustation improving the interfacial adhesion.
More generally, the expression “mechano-chemical” is understood as describing any operation which simultaneously comprises a mechanical component and a chemical component.
In this aspect, the present invention therefore enables carrying out, without any latent period between the various operations, a surface treatment of a material which groups together mechanical operations and chemical operations which are linked to the reactivity of the interfaces, and this provides a more particular advantage with respect to the treatments of the prior art which are always sequential.
Another advantage of this method resides in the fact that it does not necessitate any specific material for its implementation, it being possible for this implementation to be carried out with the aid of apparatuses whi
Breton Pascal
Brú-Magniez Nicole
Kurdyk Benrard
Richard Joël
Roques-Carmes Claude
Dennison, Schultz & Dougherty
Eley Timothy V.
Virsol
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