FR3054168A1 - METHOD FOR ENCAPSULATING AUTOMOTIVE GLAZING - Google Patents

Abstract

The invention relates to a method for manufacturing automotive glazings, comprising a) the provision of a window with two main faces and a slice, having a shape allowing, without additional deformation, to incorporate it as glazing in the window. bodywork of a vehicle, b) the application, on at least one main face of the pane along the edge thereof, of a primer composition so as to form, after drying, a primer layer, c) heating the window and the primer layer to a temperature between 60 and 130 ° C so as to activate the primer layer, d) inserting the pane into an encapsulation mold so that the cavity of the mold forms a sealed frame around the edge of the window carrying the activated primer layer, e) injecting a fluid encapsulation composition into the mold cavity, f) curing the encapsulating composition, and g) demolding glazing, characterized p in that step (c) of heating the glass includes selectively heating the peripheral zone of the glass covered by the primer layer to a temperature between 60 and 130 ° C, while most of the central part of the glass, not covered by the primer layer, remains at a temperature below 40 ° C.

Description

® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number: 3,054,168 (to be used only for reproduction orders)

©) National registration number: 16 57039

COURBEVOIE

©) Int Cl ⁸ : B 32 B 17/10 (2017.01), C 03 C 17/32, B 60 J 10/70, 1/00

A1 PATENT APPLICATION

©) Date of filing: 07.22.16. (30) Priority: © Applicant (s): SAINT-GOBAIN GLASS FRANCE - FR. ©) Inventor (s): LANGEVEN STEPHANE. ©) Date of public availability of the request: 26.01.18 Bulletin 18/04. ©) List of documents cited in the preliminary search report: See the end of this booklet (© References to other related national documents: ©) Holder (s): SAINT-GOBAIN GLASS FRANCE. ©) Extension request (s): @) Agent (s): SAINT-GOBAIN RECHERCHE.

A METHOD FOR THE ENCAPSULATION OF AUTOMOTIVE WINDOWS.

FR 3 054 168 - A1 ftv) The invention relates to a method for manufacturing automobile glazing, comprising

a) the provision of a window with two main faces and a section, having a shape allowing, without additional deformation, to incorporate it as glazing in the bodywork of a vehicle,

b) the application, on at least one main face of the pane along the edge thereof, of a primer composition so as to form, after drying, a primer layer,

c) heating the glass and the primer layer to a temperature between 60 and 130 ° C. so as to activate the primer layer,

d) insertion of the glass in an encapsulation mold so that the mold cavity forms a tight frame around the edge of the glass carrying the activated primer layer,

e) injection of a fluid encapsulation composition into the mold cavity,

f) hardening of the encapsulation composition, and

g) demolding the glazing, characterized in that the step (c) of heating the glass comprises selective heating of the peripheral zone of the glass covered by the primer layer at a temperature between 60 and 130 ° C., while most of the central part of the glass, not covered by the primer layer, remains at a temperature below 40 ° C.

-1 PROCESS FOR ENCAPSULATION OF AUTOMOTIVE WINDOWS

The present invention relates to a new method for manufacturing automotive glazing comprising a step of localized peripheral preheating of the glass, immediately before insertion of the latter into the encapsulation mold.

In the industrial field of automobile glazing, the term "encapsulation" designates a process or a step of overmolding a polymeric material around the perimeter of a window. The material is injected in the fluid state into a mold forming a sealed frame around the edge of the glass. After the material has hardened by polymerization and / or crosslinking reaction (in the case of thermosetting polymers) or by cooling (in the case of thermoplastic polymers), the mold is opened and removed, leaving a profiled bead in contact with the wafer on the periphery of the glazing. and with at least one of the two sides of the glass, often with both sides of the glass.

The polymer forming the profiled bead is often an elastomer capable of playing the role of joint between the glazing and the bodywork. Polymers which are not elastomers can however also be encapsulated by encapsulation to perform other functions.

The encapsulation step is generally preceded by a cleaning and activation step of the surface to be molded, on the periphery of the glazing, then a primer is applied to the activated area intended to come into contact with the molded profiled bead. The primer layer must then be activated by heating to be able to react with the encapsulating polymer.

This heating step is generally carried out in ovens comprising sources of infrared radiation where the entire glass is heated uniformly to a temperature of about 60 ° C to 130 ° C. The hot glass is then quickly transferred to the encapsulation station where it is inserted into an encapsulation mold forming a sealed frame around its edge.

-2 To guarantee the reproducibility of the quality of the seal, the temperature of the mold cavity - generally between 30 ° C and 40 ° C - must be stabilized, for example by circulating a coolant.

The difference between the fairly high uniform temperature of the glass 5 and the moderate temperature of the mold which comes into contact with the glass on the periphery thereof can lead to undesirable internal mechanical tensions, or even to breakage problems. glass at the time of encapsulation.

Furthermore, heating the windows with infrared lamps in the ovens does not immediately make it possible to realize the failure of a lamp. Irregular heating will thus result in the manufacture of many parts where the encapsulation seal does not adhere satisfactorily to the glass. The present invention overcomes this drawback by ensuring a homogeneous activation of the primary.

Finally, the present invention makes it possible to significantly shorten the cycle time of the process by making the glazing cooling step superfluous until room temperature at the end of the demolding step.

The present invention more particularly relates to a process for manufacturing glazing, preferably automotive glazing, comprising

a) the provision of a window with two main faces and a section, having a shape allowing, without additional deformation, to incorporate it as glazing in the body of a vehicle,

b) the application, on at least one main face of the window pane along the edge thereof, of a primer composition so as to form, after drying, a primer layer,

c) heating the glass and the primer layer to a temperature between 60 and 130 ° C so as to activate the primer layer,

d) insertion of the glass in an encapsulation mold so that the mold cavity forms a tight frame around the edge of the glass carrying the activated primer layer,

e) injection of a fluid encapsulation composition into the mold cavity,

f) hardening of the encapsulation composition, and

-3g) demoulding of the glazing, characterized in that the step (c) of heating the glass comprises selective heating of the peripheral zone of the glass covered by the primer layer at a temperature between 60 and 130 ° C. , while most of the central part of the glass, not covered by the primer layer, remains at a temperature below 40 ° C, preferably at a temperature below 30 ° C.

The term glass denotes in the present application both monolithic panes formed from a single sheet of glass and laminated panes comprising at least two sheets of glass joined together by means of a polymer sheet, generally called "laminating interlayer".

The glazing produced by the process of the present invention is preferably automotive glazing, such as windshields, side glazing, rear glasses or even glass roofs. They generally have a domed shape allowing them to be incorporated, without deforming them, into the body of a vehicle, preferably a motor vehicle.

The liquid primer composition is applied to at least one main face of the glass, preferably on the two main faces and optionally also on the edge thereof.

This application can be done manually or automatically by spraying, application with a tampon.

After application of the primer composition, the solvent contained in it is allowed to evaporate so as to form a primer layer. This primer layer preferably covers the entire area where the encapsulation material will come into contact with the glass. This contact zone between the pane and the encapsulating material is located in a peripheral zone of the pane, near the edge of the latter.

In a preferred embodiment of the method of the invention, this peripheral zone of the glass covered by the primer layer extends, without interruption, over the entire edge of the glass.

-4Its width is not necessarily uniform all around, it can be wider in some places than in others. Preferably the width of the peripheral zone of the glass covered by the primer layer varies between 1 cm and 10 cm, preferably between 1.5 cm and 8 cm, in particular between 2 and 6 cm.

The peripheral area covered by the primer layer surrounds a central area which will not come into contact with either the primer composition or the encapsulation material.

This central zone typically represents from 70% to 98% of the surface of a main face, preferably from 80% to 96% and in particular from 85 to 95% thereof.

The peripheral zone of the glass covered by the primer layer represents the complementary part of the surface of the main face of the glass, that is to say typically from 3 to 30%, preferably from 4 to 20% and more preferably from 5 to 15% of it.

The selective heating of the peripheral zone of the glass covered by the primer layer can be done by any suitable means allowing a rapid increase in the temperature of the primer layer and of the underlying glass in an area essentially limited to the extent of the primer layer.

This heating is preferably done without contact between the heating means and the primary layer so as not to damage the latter.

The selective heating of the peripheral zone carrying the primer layer can be done for example by means of a flow of hot air or a source of radiation, preferably infrared radiation.

In a preferred embodiment, the peripheral zone carrying the primer layer is heated by means of a flow of hot air. The temperature of the hot air is preferably between approximately 180 ° C and 280 ° C, in particular between 220 ° C and 270 ° C.

Such a flow of hot air can be created, for example by one or more juxtaposed fixed heat guns or by one or more guns with

-5 mobile heat sweeping the area to be heated and preferably controlled by an automatic system.

In a preferred embodiment, the heat gun (s) inject the flow of hot air into a distribution device which has an air circulation channel whose shape is similar, or even identical to that of the zone to be heated. This air circulation channel has a plurality of through openings, preferably regularly spaced, through which the hot air is directed towards the window.

Other embodiments can however be envisaged on condition that the rapid and selective heating of the peripheral zone of the glass is allowed without heating of the central zone. It is considered that the heating tool is sufficiently effective and therefore that the heating is sufficiently rapid when the main face is brought from ambient temperature (20 ° C) to activation temperature (60 - 130 ° C) in less than two minutes, preferably in less than a minute.

Of course, such local and rapid heating only makes sense if the step of overmolding the encapsulation material occurs quickly after the end of the heating. Indeed, if too much time elapses between the end of heating and the start of the injection of fluid mass of polymer into the mold, the temperature of the glass will become uniform by conduction, because glass is a good thermal conductor.

Consequently, the period between the end of the heating step and the start of the step of injecting an encapsulation composition into the mold cavity is preferably between 1 and 100 seconds, better still between 5 and 60 seconds, and in particular between 10 and 40 seconds.

The encapsulation composition injected into the cavity of the encapsulation mold may be a thermosetting composition, the components of which react with each other after injection into the mold, or it may be a thermoplastic composition containing a plasticized polymer and fluidized by heating. which hardens on cooling.

Thermoplastic encapsulation compositions are preferred and mention may be made, as examples, of thermoplastic polymers

-6particularly interesting for encapsulation of thermoplastic elastomers (TPE), in particular styrenic thermoplastic elastomers (TPE-S), and poly (vinyl chloride) (PVC).

The TPE-S which can be used in the present invention mainly comprise the following families:

- SBS (styrene-butadiene-styrene): block copolymers comprising a central block of polybutadiene framed by two blocks of polystyrene,

- SEBS: (styrene-ethylene-butadiene-styrene): copolymers obtained by hydrogenation of SBS,

- SEPS (styrene-ethylene-propylene-styrene): copolymers comprising a central poly (ethylene-propylene) block flanked by two blocks of polystyrene,

- SEEPS (styrene-ethylene-ethylene-propylene-styrene):

copolymers obtained by hydrogenation of styrenebutadiene / isoprene-styrene copolymers.

These polymers are available on the market in grades containing mineral fillers, but also in the form of materials without fillers.

In the present invention, use will be made of TPEs essentially free of fillers, or containing less than 5% of mineral fillers, preferably less than 2% of mineral fillers.

They are available, for example, under the following trade names: Dryflex (Hexpol TPE), Evoprene (AlphaGary),

Sofprene (SOFTER), Laprene (SOFTER), Asaprene (Asahi Kasei), Nilflex (Taroplast).

These products may contain a certain fraction of plasticizers, plasticizers or organic lubricants which is considered in the present application to be part of the TPE-S fraction of the thermoplastic composition.

The melting point of TPE-S is advantageously between 180 ° C and 210 ° C, in particular between 190 ° C and 200 ° C.

-7 In the molten state they must be sufficiently fluid to be able to be injection molded. It is however impossible to give precise indications concerning their viscosity in the molten state since this depends not only on the temperature but also on the shear force to which the polymers are subjected. Suppliers generally offer so-called "injection molding" qualities.

Claims (8)

1. A method of manufacturing automotive glass, comprising a) the provision of a window with two main faces and a section, having a shape allowing, without additional deformation, to incorporate it as glazing in the body of a vehicle, b) the application, on at least one main face of the window pane along the edge thereof, of a primer composition so as to form, after drying, a primer layer, c) heating the glass and the primer layer to a temperature between 60 and 130 ° C so as to activate the primer layer, d) insertion of the glass in an encapsulation mold so that the mold cavity forms a tight frame around the edge of the glass carrying the activated primer layer, e) injection of a fluid encapsulation composition into the mold cavity, f) hardening of the encapsulation composition, and g) demolding the glazing, characterized in that the step (c) of heating the glass comprises selective heating of the peripheral zone of the glass covered by the primer layer at a temperature between 60 and 130 ° C., while most of the central part of the glass, not covered by the primer layer, remains at a temperature below 40 ° C, preferably at a temperature below 30 ° C. 2. Method according to claim 1, characterized in that the selective heating of the peripheral zone of the glass covered by the primer layer is done by means of a flow of hot air or a source of infrared radiation, preferably by means of a hot air flow. 3. Method according to claim 2, characterized in that the hot air is at a temperature between about 180 ° C and 280 ° C, in particular between 220 ° C and 270 ° C. 4. Method according to one of the preceding claims, characterized in that the peripheral zone of the glass covered by the primer layer extends, without interruption, over the entire edge of the glass. -9 5. Method according to any one of the preceding claims, characterized in that the width of the peripheral zone of the glass covered by the primer layer is between 1 cm and 10 cm, preferably between 1.5 cm and 8 cm, in particular between 2 and 6 cm. 5 6. Method according to any one of the preceding claims, characterized in that the peripheral zone of the glass covered by the primer layer represents from 3 to 30%, preferably from 4 to 20% and more preferably from 5 to 15 % of the surface of the main face of the glass. îo 7. Method according to any one of the preceding claims, characterized in that the period between the end of the heating step and the start of the step of injecting an encapsulation composition into the cavity of the mold is between 1 and 100 seconds, preferably between 5 and 60 seconds, in particular between 10 and 40 15 seconds. 8. Method according to any one of the preceding claims, characterized in that the encapsulation composition comprises a styrenic thermoplastic elastomer (TPE-S) or a poly (vinyl chloride) (PVC).