ES2238190A1 - Fabrication of partially metallized ceramics and e.g. glassware consists of vapor phase deposition after silk screen printing of the workpiece for forced evaporation in the metallizing zones masked in this way - Google Patents

Abstract

The fabrication of partially-metallized ceramics and e.g. glassware comprises vapor-phase deposition after silk screen printing of the workpiece and forced evaporation of the printing to define the non-metallizing zone. Also claimed is the product of the process. CLAIMED PRODUCT - The product is freed from the metallizing applied in the silk-screen printed area.

Description

Procedure for manufacturing parts ceramic, glass or porcelain with partial metallization by vapor deposition and product thus obtained.

Field of the Invention

This refers to a process for partially metallize objects and the objects thus obtained. The invention has application in the production of objects with a partial metallized coating, especially ceramic pieces, of glass or porcelain.

Background of the invention

The PVD technique (Physical Deposition in Steam Phase) basically consists of depositing by transfer of particles a thin layer of metal on the surface object of the treatment, in which the working temperature ranges between 100 and 400 ° C For this, a vacuum chamber is used and the metal that is deposited on the previously desired piece ionized

PVD installations are hermetic, they cover very low pressures (10-2-10-3 mbar) and the reactions are achieved by ionizing the reagents (state plasma). Except for some exceptional installation are processes that They are performed discontinuously. By working conditions are considered clean and environmentally friendly.

These techniques are therefore essentially different from treatments in chemical, electrolytic or galvanic conducted in open facilities.

The impulse in the development of coatings PVD that occurred during the decade of the seventies had for aim to deposit layers of high hardness that will improve the wear performance in functional parts. These layers are formed by ceramic compounds. The compound that reached the highest expansion and popularity was in TiN (titanium nitride). Its color dorado opened high expectations regarding its use in decorative applications: the high color adds the high Surface hardness. In this way the deposition of layers began PVD as a single layer or complementary layer to those obtained by galvanic, electrolytic or chemical processes and for purposes Decorative

The fields of greatest application in decorative PVD they are as diverse as kitchenware, construction (taps, door and furniture knobs), jewelry (components of watchmaking), biomaterials and ornamentation in general. But nevertheless, day by day it increases its use in other sectors such as the building coverings, whether ceramic, glass or Porcelain, where metallizations have been used with fundamentally decorative purpose.

The advantages of coatings obtained by PVD are its low environmental impact and the physical characteristics of the coating (metallic appearance, hardness, minimum thickness, etc.). In addition the reproducibility of results in different loads is very high. The new reactors generation are becoming more precise in controlling the parameters

Of the different techniques of PVD that exist in the industry, in decoration it is possible to emphasize the denominated PVD by electric arc and PVD by sputtering. There is also the possibility of reactors that alternate both techniques The evaporation medium during the coating stage It is always physical. In both techniques the stages of the process are the following:

Reactor load

High vacuum (10-5 mbar minimum)

Warming-degassing of The pieces

Ionic pickling

Covering

Cooling and discharge

The difference between the techniques is based on the evaporation system of the metal or compound to deposit. If he evaporation system is produced by the effect of an electric arc that travels over the metal (cathode) is about evaporation by arc. If evaporation occurs by bombardment on the metal or ceramic (in this case the white or cathode does not have to be metal) of an ion beam of an inert gas (Ar) the technique is called Sputtering.

Ionization can be optimized by magnetic fields (magnetron) applied on the target. Generated reactive ions gases are introduced at very low pressure to Form the compounds. To focus on the pieces, it apply a potential difference (continuous or pulsating) between them and the reactor chamber.

The technological development of the PVD coating in decoration has focused on obtaining new coatings with different textures and colors (gold tones old and cobalt gold are some of the best known), coating of new materials (bronzes, brass, Zamack, plastics) and above all to achieve color reproducibility, brightness, hue, adhesion in each process. Unlike coating of functional parts where hardness, low coefficient friction and adhesion are the properties to consider (cutting tools, molds, dies, etc.), aspects Aesthetics are the fundamentals in decorative PVD.

Non-conductive materials such as plastic, glass and Crystal can be coated, too, using PVD techniques. The plastics coated with chrome or nickel are coated with sum ease. In the case of glass, glass or uncoated plastic, the coating is obtained by condensation on the piece obtaining acceptable adhesions. The coating of these Materials requires extreme cleaning and preparation superficial.

Indeed, for the process to give the results It is important that the surface to be coated is perfectly clean and that no steam is released or gaseous emission since the material transfer must be done in a pure environment (vacuum chamber).

In some decorative applications it is desirable that the metallic coating is partial, that is, occupies a part of the surface, leaving areas free of metallization or forming designs. In the case of PVD coatings this is difficult to achieve since the entire piece is coated.

In the state of the art it has been tried introduce decorative motifs on the metallic layer, by example by printing, engraving or electroforming. Those methods have the disadvantage that first you have to cover the entire piece and then processed to add the reason decorative, with the complication associated with the additional stages and The low quality and definition of the decoration obtained.

For example, in patent DE 101 23 344 proposes to introduce the decoration once the piece is covered by PVD by ablation with a laser.

Therefore there is still a need for provide a process that allows to introduce partial metallization or designs on the surface of a piece, in a simple and With high quality. This problem is hereby resolved. invention.

Object of the invention

The present invention aims at provide a process that allows partial metallization by PVD of a surface, in a simple and efficient way, resulting in a product with a high quality metallic and contours crisp

In one aspect, the present invention consists of a process for the partial metallization of the surface of a piece by physical vapor deposition (PVD) comprising Order the stages:

to)

treatment of the piece by screen printing to define the area that will be free of metallization,

b)

treatment of the screen-printed piece to force the evaporation of gas from the paint of serigraphy,

C)

treatment of the piece in a chamber PVD to coat the surface with a metallized,

d)

metal removal in the area treated by screen printing.

In a variant the pieces to be treated by the Process of the invention are ceramic, porcelain or glass, preferably ceramic.

Among the ceramic pieces that can be treated there are the tiles, borders, tacos, Iístelos, moldings, skirting boards. Among the porcelain pieces is the stoneware used in Construction and decoration. The glass pieces are, preferably, those used for wall cladding in construction that are recently replacing the parts Traditional ceramics

In a preferred aspect of the invention the product used for screen printing is a refractory paint inorganic

In a variant the product used for the Screen printing is chemically stable at temperatures above 500 ° C It preferably has an apparent density between 1.8 and 2.5 kg / dm3.

In another variant the product used for the Screen printing is soluble in water after cooking at a temperature above 500 ° C. In this case the elimination stage Metallizing is done by washing.

Brief description of the figures

Figure 1 graphically describes the process of the invention: 1) area to be treated; 2) silkscreen area; 3) zone coated after application by PVD; 4) zone after Clean the screen printed material.

Figure 2 shows a comparative example of Application: A) with climbing or non-flame retardant metal insole; B) according the invention.

Detailed description of the invention

They have been coming for about four years totally covering ceramic pieces by applying metallic P.V.D.

This technique, as already described, consists basically in depositing by particle transfer a thin layer of metal on the surface object of treatment, in the one that the temperature of work oscillates between 100 and 400 °. With that parts of high added value are obtained, especially in the construction materials sector.

This surface must be perfectly clean and do not give off any type of steam or gaseous emission since the material transfer must be done in a pure environment (chamber of empty).

In view of the quality of metallization obtained by PVD and relative cleanliness and simplicity of the process, it would be commercially and artistically very interesting the partial application of P.V.D. (only in the chosen areas).

An alternative is to use masks or templates on the surface to be coated before inserting them into the PVD camera. Although it avoids later stages of processing, It has the disadvantage that the contours obtained are not crisp, presenting a halo, fence or small spots when entering the steam through the gap between the template and the piece, given the rigidity of both. In the case of ceramic pieces or porcelain tiles in which the metallic coating by PVD is made at high temperatures, there is the additional problem that masks deteriorate due to temperature, affecting quality of the metallic.

The different attempts that have been made in In this sense, they have failed because any material deposited as a mask on the surface to be treated presented inconveniences:

1st) If you intended to use protective masks metallic, its rigidity and therefore its lack of adaptation to the surface to be treated, allowed steam to enter between them (template and piece) preventing sharp contours.

2nd) If the option chosen was to apply a product in traditional screen printing, the evaporation of the screen printing vehicle it contaminated the chamber and therefore hindered or prevented metallization.

3rd) If you considered using climbs or masks of plastic they burned, and when it was made with materials flame retardants, when trying to adhere them to the piece in the process so that there were no gaps between the piece and the template was the tail used which gave off gases.

4th) In short, using materials Plastics or organic gases are produced that prevent the necessary environmental purity of the process since in the vaporization process high temperatures are generated.

Therefore the composition of the materials that could be introduced into the vacuum chamber, to delimit decorative areas, without emitting gases and at the same time could be applied so that there are no cracks or fissures where steam could be introduced damaging the contours between the chosen decoration and the treated surface.

In ceramic, porcelain, and recently in glass screenprints are used for coloring or partial enamelling or Totally the pieces. Screen printing is a printing process widely documented and widely used, for decades, in the ceramic decoration.

These silkscreens are generally viscous or semi-liquid and have an emulsifier that subjected to high temperatures evaporate (even those of aqueous component). For the both a priori these gases or vapors prevent the application of PVD

Surprisingly it has been found that submitting the pieces to a previous screen printing process and forcing the evaporation of the gaseous components a piece is obtained easily metallizable by PVD and in which the metallized on the area where the screen printing was applied can be removed to give a high quality partial metallization with sharp contours.

According to the process of the invention the metallization Partial surface of a piece by PVD is achieved by the following stages, and in the order given:

to)

treatment of the piece by screen printing to define the area that will be free of metallization,

b)

treatment of the screen-printed piece to force the evaporation of gas from the paint of serigraphy,

C)

treatment of the piece in a chamber PVD to coat the surface with a metallized,

d)

metal removal in the area where there was screen printing.

For example, a paint of the form is deposited usually used in screen printing on a piece of pottery, of glass or porcelain covering only a desired part of the surface to be treated and we force the evaporation of its gases, outside of the camera. To do this, heating to sufficient temperatures to force that evaporation.

We obtain an inert product that no longer reacts at the temperature and that can be introduced into the PVD chamber without alter and without interfering with the phase deposition process steam. In the chamber the working temperature is between 100 and 400 ° C

In this way the metal transferred by the PVD process will cover the entire piece, including screen printing.

Subsequently the screen printing and the metal deposited on top of it, for example by a light washed.

The process to get the mask applied is by screen printing, a system widely known and used by the ceramic industry

It is important that the product that is applied to getting said mask is treated in a way that is compatible with the metallization and that does not release gases in the PVD chamber.

Preferably a paint is used inorganic refractory. It is preferred that you have the following physical characteristics:

-

Chemically stable at high temperatures (> 500 °)

-

Soluble in water after cooking a more than 500 °

-

Bulk density between 1.8 and 2.5 Kg / dm3. suitable for application in screen printing.

The process, although it is more widely applied, It has interest for the treatment of ceramic pieces, porcelain and glass, especially decorative pieces and / or with utility as building materials.

For example for tiles used in construction and decoration, on floor or wall tiles, borders, tacos, list them, moldings, skirting boards, etc. (special pieces ceramics that combine with pavements or coverings construction employees).

Similarly it can be applied to glass (pavement, cladding and corresponding parts complementary) and porcelain stoneware with its matching pieces. Too ornamental pieces of glass, ceramic or porcelain.

Example

An example of a product that gathers these Features is Keraplast (trademark of the Pyroterm Group), a refractory paint 1650 ° C.

Ceramic pieces were prepared according to the process described above. For screen printing it was used Keraplast that was partially applied on the pieces. Subsequently a treatment was made by heating such form that gas elimination was forced. The pieces so treated they were introduced in a PVD chamber and metallized at temperatures ranging between 100 and 400 ° C. Once the metallization is finished They washed the pieces. Figure 2B shows the pieces obtained Through this procedure.

Claims (11)

1. A process for the partial metallization of the surface of a piece by physical vapor deposition (PVD) which comprises in order the stages
country:

to)

treatment of the piece by screen printing to define the area that will be free of metallization,

b)

treatment of the screen-printed piece to force the evaporation of gas from the paint of serigraphy,

C)

treatment of the piece in a chamber PVD to coat the surface with a metallized,

d)

metal removal in the area treated by screen printing.

2. Method according to claim 1 characterized in that the piece is ceramic, porcelain or glass, preferably ceramic. 3. Method according to claim 2, characterized in that the piece is ceramic, preferably selected from the group consisting of a tile, a border, a block, list it, a molding, or a rolling
foot. 4. Method according to any of claims 1-3 characterized in that the product used for screen printing is an inorganic refractory paint. 5. Method according to any of claims 1-3 characterized in that the product used for screen printing is chemically stable at temperatures above 500 ° C. Method according to any one of claims 1-3, characterized in that the product used for screen printing is soluble in water after cooking at a temperature above 500 ° C. 7. Method according to any of claims 1-6, characterized in that the step of removing the metallization is done by washing. 8. Method according to any of claims 1-7, characterized in that the working temperature in the PVD chamber is between 100 ° C and 400 ° C. 9. Method according to any of claims 1-8, characterized in that step b) is carried out by heating. 10. Product obtainable through the process according to any of claims 1-9. 11. Product according to claim 10 characterized in that the product is a ceramic, porcelain or glass piece, preferably ceramic.