Title of Invention	ACTIVATION OF A GLASS SURFACE
Abstract	The invention relates to a pane of curved glass, at Least one of the main faces of which is activated. The activation may especially be performed by abrasion by direct rubbing of the glass surface. Advantageously, an abrasive belt closed on itself and traveling over the surface of the glass is used. After activation, a hydrophobic coat may be deposited using, for example, a fluorinated silane. The glass coated with a hydrophobic coat may be used as window glass for a motor vehicle.

Title of Invention

ACTIVATION OF A GLASS SURFACE

Abstract

The invention relates to a pane of curved glass, at Least one of the main faces of which is activated. The activation may especially be performed by abrasion by direct rubbing of the glass surface. Advantageously, an abrasive belt closed on itself and traveling over the surface of the glass is used. After activation, a hydrophobic coat may be deposited using, for example, a fluorinated silane. The glass coated with a hydrophobic coat may be used as window glass for a motor vehicle.

Full Text	ACTIVATION OF A GLASS SURFACE The invention relates to a process for activating the surface of glass to make it more receptive to subse- quent treatments, generally for the deposition of coats, for instance a hydrophobic coat. Hydrophobic properties are desired for glazing and windshields in the transportation field, in particular for motor vehicles and aircraft, and also for glazing in the construction field. For applications in the transportation field, rain-repelling properties are desired, the drops of water on windshields thus needing to run easily along the glass wall in order to be removed, for example under the effect of the air and wind when the vehicle is running, with the aim of improving the visibility and, consequently, the safety, or to facilitate the cleaning, to remove frost easily, etc. It is estimated that the surface of a substrate is hydrophobic 1f the angle of contact of a drop of water with the substrate is greater than 60° or 70°, without the drop of water becoming crushed or spread. Specific- ally, glazing is said to be functional as long as this angle is greater than 60° for aviation and 70° for motor vehicles. However, it is appropriate in practice to exceed in all cases a value of 90°, the ideal being to obtain running of the drops that allows the water to be removed so quickly that the windshield wipers can be dispensed with as much as possible in the motor vehicle field. Moreover, the improvement of the hydrophobic properties that is thus sought should not take place to the detriment of the conservation of the other proper- ties, such as the resistance to mechanical constraints: tangential friction resistance (Opel test, standardized under dry conditions), the abrasion resistance (Taber), the resistance to wiping with windshield wipers (test simulating the sweep cycles of a windshield wiper); the resistance to environmental constraints (WOM test of resistance to UVA or Xenon test; QUV test of resistance to UVR for aircraft; BSN test of resistance to neutral Saline 10g) ; the resistance to chemical constraints: test of resistance to acidic and basic detergents; and the optical properties. The Applicant has observed that coats of diverse nature (including hydrophobic coats) held less well when the surface of a glass substrate showed a certain degree of ageing in ambient air. Such ageing undoubtedly arises from the change in the chemical state of the surface. The coats deposited on an aged surface present overall less adhesion, and less uniform adhesion. It is estimated that a surface is substantially aged once it has spent at least one hour in ambient air below 100°C. Thus, any glass object that has been normally stored in order to be taken later to apply a deposit has a surface that is aged within the meaning of the invention. This type of aged surface may especially be the surface of curved glazing, especially for motor vehicles, for example motor vehicle side window glass. It is noted that the surface of a glass coming directly from a flat glass forming plant naturally has an activated and thus non-aged surface. If it is not left for too long, a coat may thus be deposited directly onto such a surface without it being necessary to perform an activation treatment. The activation process according to the invention is applied directly to the surface of the glass without it being necessary either to heat or to apply a particular undercoat in order to regenerate the surface. According to the invention, the surface is regenerated (or "activated" or "buffed") by abrasion, i.e. removal of material, even if this abrasion may be so light that its effects are not visible to the naked eye or even, where appropriate, to a scanning electron microscope. Thus, this abrasion may even be of the order of an atomic tohocoat. This abrasion is thus applied directly to the glass surface not containing any coats (a coat may optionaly be present on the face that is not to be activated). This treatment is applied to the entire surface, i.e. especially to the periphery and the central area. The use of any chemical product that attacks glass, for instance an acid, is not necessary to activate the surface, neither before, nor during, nor after the present abrasion treatment, even before the application of any surface coat or undercoat. This abrasion may especially be performed by treating the surface with a plasma or an ionized gas at reduced or atmospheric pressure, chosen from air, oxygen, nitrogen, argon, hydrogen, helium and ammonia, or a mixture of these gases, or an ion beam. This abrasion may also be performed by rubbing the surface with a polishing abrasive. The abrasive comprises abrasive grains. The term "polishing" is slightly incorrect in the present context since the abrasive wi11 make the surface slightly coarse, such that, in general, the surface is slightly coarser after polishing than before. Nevertheless, it is "polishing" abrasives that may be used. The abrasive material may especially be very fine cerium oxide (particle size: for example 0.1 to 5 µm) . Preferably, the grains of abrasive are fine enough not to create scratches that are visible to the naked eye. Preferably, the abrasion does not produce any scratches that are visible to the naked eye. The polishing treatment may be performed manually. In this case, an operator passes an orbital sander fitted with a pad of the Scotchbrite type or a cotton pad over the surface, which has also received a dispersion comprising a liquid, generally an aqueous liquid, and an abrasive powder, for instance a cerium oxide powder. The dispersion may contain, for example, 5% to 30% by weight of cerium oxide. The surface is then rinsed with water. A composite abrasive at the same time comprising a support acting as matrix for the abrasive grain held on the surface of the support may also be used. In this case, during the polishing operation, it suffices to add water to the surface to be treated. The composite abrasive may also be applied to the orbital sander by an operator. After rinsing, the glass is dried. The polishing treatment may also be performed automat- ically. To do this, a composite abrasive described above may preferably be used. This abrasive may have the form, for example, of a disk and may be driven in a roidtional motion during the polishing action. A belt, generally closed on itself, may also be used as abrasive. The machine fitted with the polishing belt may be one of those usually used for flashing or deburring metal components. The glass may be handled by a robot. The robot grips the glass by means of suction pads applied to the main face (which is generally concave) opposite the face to be treated. Water is continuously sprayed onto the surface and the polishing belt during the treatment so as to gradually remove the cerium oxide and also the polishing debris. The robot applies half of the glass against the traveling belt, and optionally rotates it by 180° to again apply it to the other half. The pressure of the belt on the glass is controlled at all times by compliance means so as to ensure homogeneous buffing. The activation treatments that have just been described activate the surface so much that the coats deposited thereafter adhere better and more homogeneously to the glass. In s activation of the surface of the glass is refiected by a strong hydrophilic nature. This hydrophilic nature is witnessed by observing whether sprayed water spreads out well and homogeneously on the surface, or by means of surface tension measurements, for example using calibration liquids of the Plasma- treat type. The activation treatment according to the invention leads to an activated and hydrophilic surface with a surface tension of at least 62 mN/m at any point. After activation according to the invention, the activ- ated surface may especially be coated with a hydrophobic coat. Generally, the hydrophobic coat itself is preceded by a mineral undercoat comprising silicon coordinated to at least one other chemical element such as 0, and/or C, and/or N, said undercoat serving as primer for the grafting of the molecules of hydrophooic nature, generally fluorinated silane molecules. The undercoat containing Si may especially consist of a compound chosen from SiOx with x less than or equal to 2, SiOC, SiON, SiOCN and Si3N4, hydrogen possibly being combined in any proportion with SiOx with x less than or equal to 2, SiOC, SiON and SiOCN. It may contain aluminum, in particular up to 8% by weight, or alter- natively carbon, Ti, Zr, Zn or B. Mention may also be made of undercoats consisting of scratchproof varnish, such as polysiloxanes, which have been applied as a coat to polycarbonate substrates. The undercoat containing Si has a thickness especially of between 1 nm and 250 nm and especially between 2 nm and 100 nm. The coat containing silicon can be deposited onto the substrate, without heating, by cathodic sputtering, under vacuum, preferably assisted by a magnetic field and/or an ion beam, or by PECVD at low pressure or at atmospheric pressure, or alternatively under hot condi- tions by pyrolysis. This coat of silica may also be produced by applying a solution of an alkoxysilane, for instance tetraethyl orthosduplite ate (or tetraethoxysilane) of formula S1 (OCH CH ) , commonly known as TEOS. A solution of TEOS in isoptopanol may especially be applied. This operation may be performed at room temperature by manual wiping by an operator. After application of the undercoat, the hydrophobic coat should be applied without delay. The reason for this is that, if there is too much of a delay, the surface of the undercoat tends to become deactivated (in the same way as the glass substrate before the activation according to the invention), and the surface of the undercoat would thus have to be reactivated. In practice, it is recommended to apply the hydrophobic coat, as quickly as possible after applying the under- coat, for the case of an application of TEOS dissolved in isopropanol, the evaporation of the solvent and the reaction of the TEOS are quick enough for it not to be necessary to perform a particular drying treatment before applying the hydrophobic coat. The hydrophobic coat may also be applied by manual wiping by an operator. To make the hydrophobic coat, it is possible to apply a compound chosen from: (a) the alkylsilanes of formula (I): CH2 (CH2) nSiRnX1-m (I) in which: - n is from 0 to 30 and more particularly from 0 to 18; - m = 0, 1, 2 or 3; R represents an optionally functionalized organic chain; - X represents a hydrolyzable residue such as a residue OR , with R representing hydrogen or a linear, branched or r.yoi o, especially C1-C8 alkyl residue; or an aryl residue, or such as a halo residue, for example chloro; (b) compounds containing grafted siloxane chains, for instance (CH3)3SiO [Si(CH3)20]2, without particular limitation as regards the chain length (value of q) and the method of grafting; (c) fluorinated silanes, for example the fluorinated salanes of formula (II): R - A SiR'-rX3-p in which R represents a mono-, oligo- or perfluoro alkyl residue, especially of C1-C9; or a mono-, oligo- or perfluoro aryl residue; - A represents a hydrocarbon-based chain, optionally interrupted with a hetero atom such as 0 or S; - R' represents a linear, branched or cyclic, especially C -C8 alkyl residue, or an aryl residue; - X represents a hydrolyzable residue such as a residue OR', with R2 representing hydrogen or a linear, branched or cyclic, especially C1-C8 alkyl residue, or an aryl residue, or such as a halo residue, for example chloro; and - p -- 0, 1 or 2 . An example of an alkylsllane of formula (I) is octa- decyltrichlorosilane (OTS). The preferred hydrophobic agents arc fluorinated silanes (c), in particular those of formula (II), particular examples of the latter being those of formula: CF- (CF3)3- (CH2)2-Si (OR4)3 in which: - R3 represents an alkyl residue; and - n is between 7 and 11. It may especially be CF3 (CF2) 7CH2CH2Si (OCH2CH3) 3 The hydrophobic agent may generally be applied manually by wiping, i.e. using a cloth impregnated with this agent, The hydrophobic coat especially has a thickness of between 1 and 100 nm and preferably between 2 and 80 nm. The f1uorinated hydrophobic coat may have a mass thickness of grafted fluorine of between 0.1 µg/cm2 and 3.5 µg/cm2 and in particular between 0.2 µg/cm2 and 3 µg/cm2 . The Opel test for characterizing the resistance of the coat(s) on the glass substrate is as follows: Construc- tion Standard En 1096-2 of January 2001, which consists in applying onto a part of the coated surface 9.4 cm long - this part being referred to as the track - a felt 14 mm in diameter, 10 mm thick and with a mass per unit volume of 0.52 g/cm2, under a load of 39.22 MPa (400 q/crri), the felt being subjected to a translation (50 to-and-fro motions over the entire length of the track per minute) combined with a rotation of 6 rpm (1 cycle - 1 to-and-fro motion). After these various treatments, it is generally desired for the glass to maintain good transparency, especially in the case of window glass for motor vehicles (or for other vehicles) . The invention relates to all glass surfaces, more particularly the window glass of motor vehicles, for instance windshields and sliding window glass and more especially side window glass. The surface of the activated glass may have an area of at least 0.25 m2 and even at least 0.3 m2 and even at least 0.35 m2 and even at least 0.4 m2. Thus, the invention also relates to a pane comprising a hydrophobic coating applied to a pane having the activ- ated surface according to the invention, an undercoat containing S possibly being applied between the glass and the nygrophobic coat. Such a pane provided with a hydrophonic coating may have a resistance in the Opel test at 5000 cycles of at least 80° (water drop angle) . The invention also relates to a windshield or sliding window glass of a vehicle, comprising a pane equipped with a hydrophobic coating according to the invention. Figure 1 shows the activation of a ½ face of a toughened motor vehicle side window glass 1 with an abrasive belt 2 closed on itself and traveling vertically by the effect of drive rollers 3 and 4. The belt is about 10 cm wide and has grains of cerium oxide on its surface. The surface to be treated is about 0.4 m2 . The window glass 1 is applied against the belt 2 by the act ion of a robot, of which only the end of the arm 5 is shown. This arm holds the window glass 1 by means of suction pads 6 (suction is created in the suction pad by means of a suction system, not shown). The direction of travel of the belt 2 is indicated by arrows. On the window glass, the belt circulates from top to not torn. Water is continuously sprayed onto the surface to be treated and onto the belt. Given the width of the belt (10 cm) relative to the width of the window glass, which is very much wider, the robot performs on the window glass a lateral motion in a direction perpendicular to figure 1, while at the same time maintaining contact with the bottom part of the window glass. When the entire lower half-face has been treated, the robot pulls back the window glass so that it is not in contact with the belt, rotates the window glass by 180° so that the top of the window glass becomes the bottom and vice versa, and places it back in contact with the belt. It then treats in the same manner the half-face that had not been treated before the rotation. This thus always avoids the belt coming into contact with an edge in the direction from the exterior of the window glass to the window glass. EXAMPLES: The surface of two window glasses is activated by abrasion. One is treated automatically with a belt as described ror figure 1, the other is a window glass treated manually by an operator using an orbital sander. The two window glasses were curved and their sheared edges were rounded off using a diamond wheel. The window glasses are identical and their main surfaces are each 0.4 m2 (a window glass has two parallel main surfaces and a sheared edge). The cerium oxide grains have a particle size of about 2 µm, whether for the automatic polishing or for the manual polishing. The window glasses are rinsed thoroughly with water and then dried. The automatic polishing leads to a surface tension of 72 mN/m (measured with Plasmatreat®) . The manual polishing leads to a surface tension of 65 mN/m, which reflects a less hydrophilic nature than in the case of the automatic polishing (it should be noted that an identical window glass that is not activated but simply degreased with an RBS soap gives a surface tension of between 50 and 60 mN/m). Identical treatments are applied to the window glasses, first a coat of silica by wiping with TEOS in iso- propanol, followed by a hydrophobic coat by wiping with a solution of a fluorosilane of formula CF.(CF ) CH2CH2Si (OCH2CH3)3. This solution was prepared by mixing together 2% by weight of silane and 98% by weight of a solvent. This solvent contained 90% by weight of 2-propanol and 10% by weight of 0. 3N HC1 in water. The resistance of the coats is then measured by the Opel test. The angle of contact of a drop of water with the surface after a certain number of cycles (5000, 2500 AND 10,000 cycles) is measured. The table below certificate the results: WE CLAIM : 1. A pane of curved glass, at least one of the main faces of which is activated, the activated surface having a hydrophilic nature such that its surface tension is at least 62 mN/m at any point, the activated surface having an area of at least 0.25 m2. 2. The pane as claimed in the preceding claim, wherein it does not contain any coats. 3. The pane as claimed in either of the preceding pane claims, wherein it is transparent. 4. The pane as claimed in the preceding claim, wherein the activated surface has an area of at least 0.3 m2. 5. A pane comprising a hydrophobic coating applied to a pane of one of the preceding claims. 6. The pane as claimed in the preceding claim, wherein an undercoat containing Si is applied between the glass and the hydrophobic coat. 7. The pane as claimed in one of the preceding claims, wherein it has a resistance in the Opel test at 5000 cycles of at least 80°. 8. A windshield or sliding window glass of vehicle, comprising a pane of one of the three preceding claims. 9. A process for activating by abrasion a pane of curved glass surface having an uncoated surface in order to produce a pane of curved glass as claimed in claim 1, wherein the abrasion is performed by means of a belt closed on itself and having abrasive grains on its surface, wherein the pane is applied against the belt by a robot. 10.The activation process as claimed in the preceding claim, wherein the abrasive grains are made of cerium oxide. 11.The process as claimed in claim 9 or 10, wherein the robot first applies half of the glass against the traveling belt, then returns it to 180°C to again apply it to the other half against the belt, the belt never coming into contact with an edge in the direction from the exterior of the window glass to the window glass. 12.A process for preparing a pane of curved glass covered on at least one of its faces with at least one coat comprising - the activation of the glass surface via the process of one of the preceding activation process claims, and then - the deposition of at least one coat. 13.The process as claimed in the preceding claim, wherein at least one coat is hydrophobic and in contact with the ambient air. 14.The process as claimed in either of the two preceding process claims, wherein no acid is used, neither before, nor during, nor after the abrasion treatment. ACTIVATION OF A GLASS SURFACE ABSTRACT The invention relates to a pane of curved glass, at Least one of the main faces of which is activated. The activation may especially be performed by abrasion by direct rubbing of the glass surface. Advantageously, an abrasive belt closed on itself and traveling over the surface of the glass is used. After activation, a hydrophobic coat may be deposited using, for example, a fluorinated silane. The glass coated with a hydrophobic coat may be used as window glass for a motor vehicle.

Full Text

ACTIVATION OF A GLASS SURFACE
The invention relates to a process for activating the
surface of glass to make it more receptive to subse-
quent treatments, generally for the deposition of
coats, for instance a hydrophobic coat.
Hydrophobic properties are desired for glazing and
windshields in the transportation field, in particular
for motor vehicles and aircraft, and also for glazing
in the construction field. For applications in the
transportation field, rain-repelling properties are
desired, the drops of water on windshields thus needing
to run easily along the glass wall in order to be
removed, for example under the effect of the air and
wind when the vehicle is running, with the aim of
improving the visibility and, consequently, the safety,
or to facilitate the cleaning, to remove frost easily,
etc. It is estimated that the surface of a substrate is
hydrophobic 1f the angle of contact of a drop of water
with the substrate is greater than 60° or 70°, without
the drop of water becoming crushed or spread. Specific-
ally, glazing is said to be functional as long as this
angle is greater than 60° for aviation and 70° for motor
vehicles. However, it is appropriate in practice to
exceed in all cases a value of 90°, the ideal being to
obtain running of the drops that allows the water to be
removed so quickly that the windshield wipers can be
dispensed with as much as possible in the motor vehicle
field. Moreover, the improvement of the hydrophobic
properties that is thus sought should not take place to
the detriment of the conservation of the other proper-
ties, such as the resistance to mechanical constraints:
tangential friction resistance (Opel test, standardized
under dry conditions), the abrasion resistance (Taber),
the resistance to wiping with windshield wipers (test
simulating the sweep cycles of a windshield wiper); the
resistance to environmental constraints (WOM test of

resistance to UVA or Xenon test; QUV test of resistance
to UVR for aircraft; BSN test of resistance to neutral
Saline 10g) ; the resistance to chemical constraints:
test of resistance to acidic and basic detergents; and
the optical properties.
The Applicant has observed that coats of diverse nature
(including hydrophobic coats) held less well when the
surface of a glass substrate showed a certain degree of
ageing in ambient air. Such ageing undoubtedly arises
from the change in the chemical state of the surface.
The coats deposited on an aged surface present overall
less adhesion, and less uniform adhesion. It is
estimated that a surface is substantially aged once it
has spent at least one hour in ambient air below 100°C.
Thus, any glass object that has been normally stored in
order to be taken later to apply a deposit has a
surface that is aged within the meaning of the
invention. This type of aged surface may especially be
the surface of curved glazing, especially for motor
vehicles, for example motor vehicle side window glass.
It is noted that the surface of a glass coming directly
from a flat glass forming plant naturally has an
activated and thus non-aged surface. If it is not left
for too long, a coat may thus be deposited directly
onto such a surface without it being necessary to
perform an activation treatment.
The activation process according to the invention is
applied directly to the surface of the glass without it
being necessary either to heat or to apply a particular
undercoat in order to regenerate the surface. According
to the invention, the surface is regenerated (or
"activated" or "buffed") by abrasion, i.e. removal of
material, even if this abrasion may be so light that
its effects are not visible to the naked eye or even,
where appropriate, to a scanning electron microscope.
Thus, this abrasion may even be of the order of an

atomic tohocoat. This abrasion is thus applied directly
to the glass surface not containing any coats (a coat
may optionaly be present on the face that is not to be
activated). This treatment is applied to the entire
surface, i.e. especially to the periphery and the
central area. The use of any chemical product that
attacks glass, for instance an acid, is not necessary
to activate the surface, neither before, nor during,
nor after the present abrasion treatment, even before
the application of any surface coat or undercoat.
This abrasion may especially be performed by treating
the surface with a plasma or an ionized gas at reduced
or atmospheric pressure, chosen from air, oxygen,
nitrogen, argon, hydrogen, helium and ammonia, or a
mixture of these gases, or an ion beam.
This abrasion may also be performed by rubbing the
surface with a polishing abrasive. The abrasive
comprises abrasive grains. The term "polishing" is
slightly incorrect in the present context since the
abrasive wi11 make the surface slightly coarse, such
that, in general, the surface is slightly coarser after
polishing than before. Nevertheless, it is "polishing"
abrasives that may be used. The abrasive material may
especially be very fine cerium oxide (particle size:
for example 0.1 to 5 µm) . Preferably, the grains of
abrasive are fine enough not to create scratches that
are visible to the naked eye. Preferably, the abrasion
does not produce any scratches that are visible to the
naked eye.
The polishing treatment may be performed manually. In
this case, an operator passes an orbital sander fitted
with a pad of the Scotchbrite type or a cotton pad over
the surface, which has also received a dispersion
comprising a liquid, generally an aqueous liquid, and
an abrasive powder, for instance a cerium oxide powder.

The dispersion may contain, for example, 5% to 30% by
weight of cerium oxide. The surface is then rinsed with
water. A composite abrasive at the same time comprising
a support acting as matrix for the abrasive grain held
on the surface of the support may also be used. In this
case, during the polishing operation, it suffices to
add water to the surface to be treated. The composite
abrasive may also be applied to the orbital sander by
an operator. After rinsing, the glass is dried.
The polishing treatment may also be performed automat-
ically. To do this, a composite abrasive described
above may preferably be used. This abrasive may have
the form, for example, of a disk and may be driven in a
roidtional motion during the polishing action. A belt,
generally closed on itself, may also be used as
abrasive.
The machine fitted with the polishing belt may be one
of those usually used for flashing or deburring metal
components.
The glass may be handled by a robot. The robot grips
the glass by means of suction pads applied to the main
face (which is generally concave) opposite the face to
be treated. Water is continuously sprayed onto the
surface and the polishing belt during the treatment so
as to gradually remove the cerium oxide and also the
polishing debris. The robot applies half of the glass
against the traveling belt, and optionally rotates it
by 180° to again apply it to the other half. The
pressure of the belt on the glass is controlled at all
times by compliance means so as to ensure homogeneous
buffing.
The activation treatments that have just been described
activate the surface so much that the coats deposited
thereafter adhere better and more homogeneously to the

glass. In s activation of the surface of the glass is
refiected by a strong hydrophilic nature. This
hydrophilic nature is witnessed by observing whether
sprayed water spreads out well and homogeneously on the
surface, or by means of surface tension measurements,
for example using calibration liquids of the Plasma-
treat type. The activation treatment according to the
invention leads to an activated and hydrophilic surface
with a surface tension of at least 62 mN/m at any
point.
After activation according to the invention, the activ-
ated surface may especially be coated with a
hydrophobic coat. Generally, the hydrophobic coat
itself is preceded by a mineral undercoat comprising
silicon coordinated to at least one other chemical
element such as 0, and/or C, and/or N, said undercoat
serving as primer for the grafting of the molecules of
hydrophooic nature, generally fluorinated silane
molecules.
The undercoat containing Si may especially consist of a
compound chosen from SiOx with x less than or equal to
2, SiOC, SiON, SiOCN and Si3N4, hydrogen possibly being
combined in any proportion with SiOx with x less than or
equal to 2, SiOC, SiON and SiOCN. It may contain
aluminum, in particular up to 8% by weight, or alter-
natively carbon, Ti, Zr, Zn or B. Mention may also be
made of undercoats consisting of scratchproof varnish,
such as polysiloxanes, which have been applied as a
coat to polycarbonate substrates. The undercoat
containing Si has a thickness especially of between
1 nm and 250 nm and especially between 2 nm and 100 nm.
The coat containing silicon can be deposited onto the
substrate, without heating, by cathodic sputtering,
under vacuum, preferably assisted by a magnetic field
and/or an ion beam, or by PECVD at low pressure or at
atmospheric pressure, or alternatively under hot condi-

tions by pyrolysis.
This coat of silica may also be produced by applying a
solution of an alkoxysilane, for instance tetraethyl
orthosduplite ate (or tetraethoxysilane) of formula
S1 (OCH CH ) , commonly known as TEOS. A solution of TEOS
in isoptopanol may especially be applied. This
operation may be performed at room temperature by
manual wiping by an operator.
After application of the undercoat, the hydrophobic
coat should be applied without delay. The reason for
this is that, if there is too much of a delay, the
surface of the undercoat tends to become deactivated
(in the same way as the glass substrate before the
activation according to the invention), and the surface
of the undercoat would thus have to be reactivated. In
practice, it is recommended to apply the hydrophobic
coat, as quickly as possible after applying the under-
coat, for the case of an application of TEOS dissolved
in isopropanol, the evaporation of the solvent and the
reaction of the TEOS are quick enough for it not to be
necessary to perform a particular drying treatment
before applying the hydrophobic coat.
The hydrophobic coat may also be applied by manual
wiping by an operator.
To make the hydrophobic coat, it is possible to apply a
compound chosen from:
(a) the alkylsilanes of formula (I):
CH2 (CH2) nSiRnX1-m (I)
in which:
- n is from 0 to 30 and more particularly from 0 to 18;
- m = 0, 1, 2 or 3;
R represents an optionally functionalized organic
chain;
- X represents a hydrolyzable residue such as a residue

OR , with R representing hydrogen or a linear, branched
or r.yoi o, especially C1-C8 alkyl residue; or an aryl
residue, or such as a halo residue, for example chloro;
(b) compounds containing grafted siloxane chains, for
instance (CH3)3SiO [Si(CH3)20]2, without particular
limitation as regards the chain length (value of q) and
the method of grafting;
(c) fluorinated silanes, for example the fluorinated
salanes of formula (II):
R - A SiR'-rX3-p
in which
R represents a mono-, oligo- or perfluoro alkyl
residue, especially of C1-C9; or a mono-, oligo- or
perfluoro aryl residue;
- A represents a hydrocarbon-based chain, optionally
interrupted with a hetero atom such as 0 or S;
- R' represents a linear, branched or cyclic, especially
C -C8 alkyl residue, or an aryl residue;
- X represents a hydrolyzable residue such as a residue
OR', with R2 representing hydrogen or a linear, branched
or cyclic, especially C1-C8 alkyl residue, or an aryl
residue, or such as a halo residue, for example chloro;
and
- p -- 0, 1 or 2 .
An example of an alkylsllane of formula (I) is octa-
decyltrichlorosilane (OTS). The preferred hydrophobic
agents arc fluorinated silanes (c), in particular those
of formula (II), particular examples of the latter
being those of formula:
CF- (CF3)3- (CH2)2-Si (OR4)3
in which:
- R3 represents an alkyl residue; and
- n is between 7 and 11.
It may especially be CF3 (CF2) 7CH2CH2Si (OCH2CH3) 3
The hydrophobic agent may generally be applied manually

by wiping, i.e. using a cloth impregnated with this
agent,
The hydrophobic coat especially has a thickness of
between 1 and 100 nm and preferably between 2 and
80 nm. The f1uorinated hydrophobic coat may have a mass
thickness of grafted fluorine of between 0.1 µg/cm2 and
3.5 µg/cm2 and in particular between 0.2 µg/cm2 and
3 µg/cm2 .
The Opel test for characterizing the resistance of the
coat(s) on the glass substrate is as follows: Construc-
tion Standard En 1096-2 of January 2001, which consists
in applying onto a part of the coated surface 9.4 cm
long - this part being referred to as the track - a
felt 14 mm in diameter, 10 mm thick and with a mass per
unit volume of 0.52 g/cm2, under a load of 39.22 MPa
(400 q/crri), the felt being subjected to a translation
(50 to-and-fro motions over the entire length of the
track per minute) combined with a rotation of 6 rpm (1
cycle - 1 to-and-fro motion).
After these various treatments, it is generally desired
for the glass to maintain good transparency, especially
in the case of window glass for motor vehicles (or for
other vehicles) .
The invention relates to all glass surfaces, more
particularly the window glass of motor vehicles, for
instance windshields and sliding window glass and more
especially side window glass. The surface of the
activated glass may have an area of at least 0.25 m2 and
even at least 0.3 m2 and even at least 0.35 m2 and even
at least 0.4 m2.
Thus, the invention also relates to a pane comprising a
hydrophobic coating applied to a pane having the activ-
ated surface according to the invention, an undercoat

containing S possibly being applied between the glass
and the nygrophobic coat. Such a pane provided with a
hydrophonic coating may have a resistance in the Opel
test at 5000 cycles of at least 80° (water drop angle) .
The invention also relates to a windshield or sliding
window glass of a vehicle, comprising a pane equipped
with a hydrophobic coating according to the invention.
Figure 1 shows the activation of a ½ face of a
toughened motor vehicle side window glass 1 with an
abrasive belt 2 closed on itself and traveling
vertically by the effect of drive rollers 3 and 4. The
belt is about 10 cm wide and has grains of cerium oxide
on its surface. The surface to be treated is about
0.4 m2 . The window glass 1 is applied against the belt
2 by the act ion of a robot, of which only the end of
the arm 5 is shown. This arm holds the window glass 1
by means of suction pads 6 (suction is created in the
suction pad by means of a suction system, not shown).
The direction of travel of the belt 2 is indicated by
arrows. On the window glass, the belt circulates from
top to not torn. Water is continuously sprayed onto the
surface to be treated and onto the belt. Given the
width of the belt (10 cm) relative to the width of the
window glass, which is very much wider, the robot
performs on the window glass a lateral motion in a
direction perpendicular to figure 1, while at the same
time maintaining contact with the bottom part of the
window glass. When the entire lower half-face has been
treated, the robot pulls back the window glass so that
it is not in contact with the belt, rotates the window
glass by 180° so that the top of the window glass
becomes the bottom and vice versa, and places it back
in contact with the belt. It then treats in the same
manner the half-face that had not been treated before
the rotation. This thus always avoids the belt coming
into contact with an edge in the direction from the
exterior of the window glass to the window glass.

EXAMPLES:
The surface of two window glasses is activated by
abrasion. One is treated automatically with a belt as
described ror figure 1, the other is a window glass
treated manually by an operator using an orbital
sander. The two window glasses were curved and their
sheared edges were rounded off using a diamond wheel.
The window glasses are identical and their main
surfaces are each 0.4 m2 (a window glass has two
parallel main surfaces and a sheared edge). The cerium
oxide grains have a particle size of about 2 µm,
whether for the automatic polishing or for the manual
polishing. The window glasses are rinsed thoroughly
with water and then dried.
The automatic polishing leads to a surface tension of
72 mN/m (measured with Plasmatreat®) . The manual
polishing leads to a surface tension of 65 mN/m, which
reflects a less hydrophilic nature than in the case of
the automatic polishing (it should be noted that an
identical window glass that is not activated but simply
degreased with an RBS soap gives a surface tension of
between 50 and 60 mN/m).
Identical treatments are applied to the window glasses,
first a coat of silica by wiping with TEOS in iso-
propanol, followed by a hydrophobic coat by wiping with
a solution of a fluorosilane of formula
CF.(CF ) CH2CH2Si (OCH2CH3)3. This solution was prepared by
mixing together 2% by weight of silane and 98% by
weight of a solvent. This solvent contained 90% by
weight of 2-propanol and 10% by weight of 0. 3N HC1 in
water.
The resistance of the coats is then measured by the
Opel test. The angle of contact of a drop of water with

the surface after a certain number of cycles (5000,
2500 AND 10,000 cycles) is measured. The table below
certificate the results:

WE CLAIM :
1. A pane of curved glass, at least one of the main faces of which is
activated, the activated surface having a hydrophilic nature such that
its surface tension is at least 62 mN/m at any point, the activated
surface having an area of at least 0.25 m2.
2. The pane as claimed in the preceding claim, wherein it does not contain
any coats.
3. The pane as claimed in either of the preceding pane claims, wherein it
is transparent.
4. The pane as claimed in the preceding claim, wherein the activated
surface has an area of at least 0.3 m2.
5. A pane comprising a hydrophobic coating applied to a pane of one of
the preceding claims.
6. The pane as claimed in the preceding claim, wherein an undercoat
containing Si is applied between the glass and the hydrophobic coat.
7. The pane as claimed in one of the preceding claims, wherein it has a
resistance in the Opel test at 5000 cycles of at least 80°.

8. A windshield or sliding window glass of vehicle, comprising a pane of
one of the three preceding claims.
9. A process for activating by abrasion a pane of curved glass surface
having an uncoated surface in order to produce a pane of curved glass
as claimed in claim 1, wherein the abrasion is performed by means of a
belt closed on itself and having abrasive grains on its surface, wherein
the pane is applied against the belt by a robot.
10.The activation process as claimed in the preceding claim, wherein the
abrasive grains are made of cerium oxide.
11.The process as claimed in claim 9 or 10, wherein the robot first applies
half of the glass against the traveling belt, then returns it to 180°C to
again apply it to the other half against the belt, the belt never coming
into contact with an edge in the direction from the exterior of the
window glass to the window glass.
12.A process for preparing a pane of curved glass covered on at least one
of its faces with at least one coat comprising
- the activation of the glass surface via the process of one of the
preceding activation process claims, and then
- the deposition of at least one coat.

13.The process as claimed in the preceding claim, wherein at least one
coat is hydrophobic and in contact with the ambient air.
14.The process as claimed in either of the two preceding process claims,
wherein no acid is used, neither before, nor during, nor after the
abrasion treatment.

ACTIVATION OF A GLASS SURFACE

ABSTRACT
The invention relates to a pane of curved glass,
at Least one of the main faces of which is
activated. The activation may especially be
performed by abrasion by direct rubbing of the
glass surface. Advantageously, an abrasive belt
closed on itself and traveling over the surface of
the glass is used. After activation, a hydrophobic
coat may be deposited using, for example, a
fluorinated silane. The glass coated with a hydrophobic
coat may be used as window glass for a
motor vehicle.

ACTIVATION OF A GLASS SURFACE

Documents:

Inventors:

PCT Conventions: