CZ286724B6 - Layered glazing assembly and process and apparatus for making the same - Google Patents

Abstract

The proposed layered glazing assembly comprises at least two flat parts (10, 11) of glassy material, an intermediate layer (14) of adhesive material and electric circuit arranged between the glassy flat parts and having an electric conductor (22) that runs over edges (24, 26) of the reaching glassy flat parts (10, 11) and that is intended for connecting with an external electric circuit. The assembly further comprises a protective body (32) made of polymeric material encapsulating at least a portion of the electrical conductor (22) running over the edges (24, 26) and adhering to adjacent edges (24, 26)). The process for producing the above-described glazing assembly is characterized in that a mold is put around a portion of the assembly where the electrical conductor (22) projects and subsequently in the form, there is formed a protective body (32) by injection molding. The apparatus for making the process has means for holding-down the assembly and a supporting frame carrying molds.

Description

A laminated glazing assembly and method and apparatus for forming the same

Technical field

The invention relates to a laminated glazing assembly and to a method and apparatus for forming it.

BACKGROUND OF THE INVENTION

It is known that heated glazing assemblies are used in motor vehicles, particularly for heated windshields, to avoid condensation or icing that otherwise forms on their surfaces and prevents visibility for the driver from the vehicle.

One particular type of heated windshield is a laminate assembly comprising two sheets of glass and a polyvinyl butyral (PVB) interlayer. Inside the assembly there is a network of fine heating fibers distributed over the area to be heated. Typically, the fibers are tungsten and have a diameter of about 20 µm and are spaced apart at intervals of 1.5 to 3 mm. The fiber web is pre-assembled and lightly attached to the PVB film before it is inserted between the glass sheets to form the assembly.

The heating fibers are arranged between the current collecting tapes (current collectors). These current collectors can be formed, for example, from copper strips of 0.05 mm thickness and 5 mm width, coated by soldering with a low melting point solder. These current collectors can be connected to the vehicle electrical wiring via the connection terminals.

The electrical conductors that extend beyond the edges of the laminated glass sheets may be copper strips forming current collectors. They may also be in the form of a fiber tape or a braided conductive wire.

French patent application FR-A-2674720 of Saint-Gobain Vitrage discloses a heated laminated glass sheet in which several resistive wires are arranged between two current collectors, at least one of which is in braided form, the current collectors extending beyond the edges of the glass panels for connection to an external electrical circuit.

This known design does not technically address the issue of liquid or vapor ingress that may occur at the conductor exit from the assembly. Further, the conductor assembly as designed is highly brittle at the point where it extends beyond the edges of the glass sheets.

SUMMARY OF THE INVENTION

Said drawbacks are eliminated by a glazing assembly comprising at least two vitreous sheets, an adhesive interlayer, and at least one electrical circuit disposed between the vitreous sheets and having at least one electrical connection conductor extending beyond the edges of the vitreous sheets for connection to an external electrical The peripheral circuit is characterized in that at least a portion of the electrical connection conductor immediately adjacent the edges of the glass sheets is encapsulated in a local protective body of polymeric material that adheres to adjacent edges of the glass sheets.

The protective body is positioned locally, i.e. in the immediate vicinity of the point where the electrical conductor extends beyond the edges of the vitreous sheets. The protective body thus preferably occupies only a small amount

And a high delamination resistance of the laminate assembly with a minimum amount of additional mass is achieved. Preferably, the local protective body is formed directly on said edges of the vitreous sheets.

Typically, the remainder of the edges of the glass sheets remain unprotected, keeping the assembly volume as small as possible. Where the protective body is also placed over the outer edge portion of the vitreous sheets, the fact that the protective body is positioned locally implies maximum visibility over the assembly.

Surprisingly, it is possible to achieve sufficient protection and mechanical strength for an electrical conductor that extends beyond the outer edges of the glass sheets while avoiding delamination of the glass sheets using a local protective body without encapsulating the entire periphery of the glass sheets.

The interlayer material may be a polymeric material having a liquid precursor by which it may solidify in place, such as an acrylic resin. Preferably, the intermediate layer is a film, for example of PVC or a copolymer of ethylene and vinyl acetate (EVA) and most preferably of polyvinyl butyral.

The glass sheet material is preferably glass, but other sheet materials may also be used provided they have sufficient strength and light transmittance.

By appropriately selecting the polymeric material relative to the glassy material, it can be ensured that any polymeric material will adhere to the glassy material. However, in some less preferred embodiments, an adhesive may be applied to the glass sheets prior to forming the protective body. It is also possible to apply an agent for improving the adhesion of the protective body material, such as silane, to the glass sheets.

Preferably, the polymeric material from which the protective body is formed is polyurethane.

Typically, the polymeric material will be electrically nonconductive so as to provide insulating protection to the electrical conductor.

Preferably, the local protective body is formed in place on the electrical conductor and the edges of the vitreous sheets, i.e. the protective body is formed after the vitreous sheets have been joined into a laminate assembly.

The entire connecting electrical conductor extending beyond the edges of the vitreous sheets may be encapsulated within the protective body and connected within the protective body to an insulated power supply cable.

According to a further feature of the invention, the electrical circuit that connects the electrical connection wire to the external circuit is a heating circuit of the assembly. Preferably, the protective body extends over and adheres to the peripheral portion of the outer main surface of each of said glass sheets.

According to another embodiment of the invention, the laminated glazing assembly comprises a plurality of electrical circuits, each having associated electrical conductors. Preferably, it comprises two heating circuits, each having two connecting electrical conductors extending beyond the edges of the glass sheets, one connecting electrical conductor of the first circuit and one connecting electrical conductor of the second circuit extending from the edges of the glass sheets in close proximity to each other and protected by a common protective body. Two additional connecting wires may extend beyond the edges of the glass sheets at spaced locations and are protected by individual protective bodies.

-2 CZ 286724 B6

The invention further provides a method for manufacturing the above-described laminated glazing assembly comprising depositing a mold around a protruding portion of the electrical conductor and an adjacent portion of the glass sheet assembly, and pouring or injecting a polymeric liquid composition in the mold cavity. the mold cavity solidifies, whereupon the mold is removed and a glazing assembly with a protective body is enclosed with at least one connecting electrical conductor.

Preferably, before forming the protective body, the at least one electrical conductor extending beyond the edges of the vitreous sheets to be encapsulated is connected to a corresponding insulated lead-in cable.

It is desirable to use a two-piece mold that is capable of clamping around the edge of the assembly and removal after forming the protective body.

Said processes are performed for each conductor that exits the laminate assembly, typically two or more.

By using multiple individual molds, multiple protective bodies can be formed simultaneously. Preferably, the polymerizable material in liquid form is injected into said mold or each of said molds and is allowed to polymerize or induce polymerization therein. These molds may be supported on a common frame structure that serves to support the assembly during molding and optionally during its individual or other manufacturing processes. This frame structure needs to be rigid in order to eliminate the risk of glass sheets breaking. It is to be understood that the glass sheets are generally curved for the purpose of forming vehicle windscreens.

The invention also provides an apparatus for forming a laminate assembly comprising: at least one mold comprising a cable passage defining a cavity for pouring or injecting a polymer mass following a recess for inserting edge portions of the vitreous sheets of the laminate assembly; and provided with an inlet for the polymer mass.

Preferably, the plurality of sub-molds are supported on a common frame, with pitches corresponding to the pitches of the individual electrical connection wires of the glazing assembly to be encapsulated in corresponding protective bodies.

According to a preferred embodiment of the device according to the invention, said at least one mold is a two-piece mold defining a mold cavity between its mold halves for pouring or injecting polymer mass, following the recess for inserting edge portions of the flat glass panes of the laminated glazing assembly.

The assembly may comprise two or more conductors extending beyond the perimeter of the vitreous sheets. A single protective body can be used for each conductor, but where the exit points of two or more conductors are close together, it is possible to create a single protective body for all such conductors.

Preferably, the electrical circuit is a heating circuit of the assembly. The assembly is thus suitable for incorporation into vehicles, particularly motor vehicles, where it can be used as a windshield, side or rear window glazing, where the heating circuit provides a means for preventing condensation or providing other functions such as enhancing thermal comfort or the like. an electrical circuit forming a radio frequency antenna.

The assembly may comprise a plurality of electrical circuits, each having its associated electrical conductors. In a typical example, a heated windshield for a vehicle may comprise two heating circuits, one for the driver of the vehicle and one for the passenger. In this case, they can be there

Four conductors extending over the edges of the vitreous sheets, two designed for ground connection (negative pole) and two designed for individually controlled power supplies (positive pole). The two ground conductors may extend from the sheets of vitreous material in close proximity to each other and may be protected by a common protective body. The two additional conductors may extend beyond the edges of the glass sheets at spaced locations and may be protected by individual protective bodies (the negative and positive terminals may of course be reversed).

Overview of the drawings

BRIEF DESCRIPTION OF THE DRAWINGS The invention is explained in more detail below with reference to the accompanying drawings, in which: Figure 1 shows a general view of a laminate assembly for use in a glazing assembly according to the invention from one side; Fig. 4A is a portion of Fig. 1 where the current header has been connected to an insulated power cord; Fig. 3B is a cross-sectional view of the arrangement of Figs. 3A, 4A and 4B showing the same views as Figs. 4A and 4B; Fig. 5A is a perspective view of part of a two-piece mold for forming a protective body, Fig. 5B is a cross-sectional view of the two-piece mold in use, taken along the VV plane of Fig. 5A; .

DETAILED DESCRIPTION OF THE INVENTION

The laminate assembly shown in the drawings comprises a pair of 2 mm glass sheets of similar shape, 2 mm thick, facing each other and separated by an interlayer 14 of 0.76 mm thick polyvinyl butyral. An electrical heating circuit comprising a plurality of heating fibers 16 disposed between the upper and lower horizontal current collectors in the form of strips 18 and 20 and forming together the electrical circuit 116 is embedded within the intermediate layer 14. As seen particularly in Fig. 3B, the horizontal current collector 20 connected to a vertical current collector 22 which extends from the laminate assembly beyond the edge surfaces 24 and 26 of the glass sheets 10 and 12 so as to terminate the terminal 28. In the context of the present invention, the vertical current collector 22 is an electrical conductor extending beyond the edges. glassy parts.

The weak point of this construction is the zone indicated by the arrow B in Fig. 2, where the vertical current collector 22 extends beyond the edge surfaces 24 and 26 of the glass sheets 10 and 12. In this region, the current collector 22 is not protected by the glass sheets 10 and 12. brittle. The movement of the current collector 22 carries with it the risk of breaking the adhesion of the sheets to the stack, which would lead to possible ingress of moisture.

The ingress of water or other liquids or gases into the outlet region B may damage the interlayer 14 which holds the glass sheets 10 and 12 together. Furthermore, the vertical current collector 22 must be electrically insulated and firmly connected to the vehicle electrical circuit assembly.

As shown in Figs. 3A and 3B, terminal 28 is brazed to an insulated flexible power supply cable 30 near the point where the current collector 22 exits the laminate assembly.

The encapsulation process consists in placing a hollow mold around the edge of the laminate assembly, which can be closed and can be liquid-tight. A small clamp mold having two movable portions may be used to clamp the mold around the edge of the assembly in zone B. Then, a polymerizable insulating material such as one or two polyurethane resins is injected into the mold, and polymerization rapidly occurs by heating the mold to e.g. ° C for 2 minutes.

The mold can then be released by release, revealing, as shown in FIGS. 4A and 4B, that the edge surfaces 24 and 26 of the glass sheets 10 and 12 are covered by the polymer body 32,

Enclosing the portion of the current collector 22 that extends beyond the edges of the glass sheets 10 and 12 and the portion of the insulated cable 30 provides protection. The protective body 32 extends beyond the edges of the glass sheets 10 and 12 and adheres to the outer surfaces of their edge portions 34 and 36. The joint is therefore insulated and protected and the conductor exit of the stacked assembly is hermetically sealed.

In a particular embodiment, the polyurethane protective body 32 is 5 cm long, 1.5 cm high, and 1 cm thick (judged in the thickness direction of the assembly).

Giant. 5A shows a perspective view of one mold half 40A of a suitable two-piece mold 10 for forming a protective body as described above. As shown in Fig. 5B, the second mold half 40B has a substantially similar construction except for the features described below.

The mold half 40A comprises a press block 41 formed of aluminum or stainless steel in which a mold cavity 42 is formed in its upper face. The injection feed channel 43 leads 15 from the upper face of the press block 41 to the cavity 42. The injection feed channel 43 is formed in only one mold parts. A leak cavity 44 extends from the cavity 42 to allow air to escape from the cavity 42 in use. Further, a passage 47 for receiving an insulated flexible lead 30 runs into the cavity 42. The mold half 40A is provided with a rebate 46A on which the laminate assembly rests during compression. The position of the laminate assembly is shown in dashed lines in FIG. 5A 20, in particular one glass sheet 12 and its edge surface 26. For the sake of clarity, the dashed lines on the inside of the mold are omitted. The depth of the rebate 46A is equal to the thickness of the layered assembly. As shown in Fig. 5B, the mold half 40B does not include a rebate corresponding to the rebate 46A shown in Fig. 5A.

FIG. 5A also shows an optional semi-cylindrical cavity. This cavity is disposed along the peripheral edge of the cavity 42 where the protective body formed therein is in contact with the vitreous sheets of the laminate assembly and terminates in the notches 49 in the sides 46B of the rebate 46A. A heat-resistant silicone sealing strip 45 (shown only in FIG. 5B) having a circular cross-section is inserted into the cavity 48. When the two mold parts are clamped together, the sealing strip 30 abuts the outer surface of the sheet 10 of the laminate assembly to form a gas-tight and liquid-tight seal. Although the figures show a sealing strip 45 housed in a cavity 48 in one mold portion 40A, it is possible for such a tape to be in both mold halves 40A, 40B. The cavity 48 can also completely surround the mold cavity 42.

The mold is provided with a plurality of passages 50, of which only one is shown in FIGS. 5A and 5B, suitable for accommodating temperature sensors and heating elements. The heating elements may be inserted when the polymerization of the injection molded polymer is to be initiated by heat.

The mold is also provided with fastening points 51 for fastening the mold to the support frame 40 (not shown in Figs. 5A and 5B), and to engage the not shown means for clamping the two parts of the mold together in use. The two mold halves 40A, 40B are hinged together so that their surfaces are parallel to each other. Both parts of the mold may be closed together manually, but hydraulic actuation is preferred, which may be more easily controlled to provide a uniform pressure against the laminate assembly.

FIG. 6 illustrates a support 41 of three molds, each of the type shown in FIGS. 5A and 5B, along one edge of the laminate assembly, in which FIG. 6 shows the sheet 12. FIG. laminated assembly. It therefore consists of supports 55 and three molds in positions 41.

Giant. 7 shows that the carriers 55 have been omitted. In this example, three molds are attached to the individual carriers 66, which are each connected via universal joints 67 to a corresponding support arm 68 carried on a common support frame 69. The carriers 66 should be arranged such that the faces of each mold in contact with the laminate assembly are parallel to it.

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The carriers 66 may be arranged in a substantially horizontal configuration with respect to each other, as shown, or may be substantially vertical or inclined. Although the description herein is directed to a heated windshield comprising a network of fibers, it will be understood that the invention also relates to an assembly heated by a conductive coating or by conductors coated where there is also a problem of a conductor extending beyond the peripheral surfaces of the vitreous sheets.

Claims (15)

A laminated glazing assembly comprising at least two vitreous sheets (10, 12), an intermediate adhesive layer (14), and at least one electrical circuit (160) disposed between the vitreous sheets (10, 12) and having at least one an electrical connection conductor (22) extending beyond the edges (24, 26) of the glass sheets for connection to an external electrical circuit, characterized in that at least a portion of the electrical connection conductor (22) immediately adjacent the edges (24, 26) of the glass sheets (10, 12) is encapsulated in a local protective body (32) of polymeric material that adheres to adjacent edges of the glass sheets (10, 12). A laminated glazing assembly according to claim 1, characterized in that the local protective body (32) is molded directly on said edges (24, 26) of the vitreous sheets (10, 12). A laminated glazing assembly according to claim 1 or 2, characterized in that the polymeric material of the protective body (32) is polyurethane. A laminated glazing assembly according to any one of claims 1 to 3, characterized in that the entire electrical connection wire (22) extending beyond the edges (24, 26) of the vitreous sheets (10, 12) is encapsulated in the protective body (32) and connected inside. a protective body (32) to the insulated power supply cable (30). A laminated glazing assembly according to any one of claims 1 to 4, characterized in that the electrical circuit (160) that connects the electrical connection conductor (22) to the external circuit is the heating circuit of the assembly. A laminated glazing assembly according to any one of claims 1 to 5, characterized in that the protective body (32) extends over and adheres to the peripheral portion (34, 36) of the outer main surface of at least one of the glass sheets (10, 12). 7. The laminated glazing assembly of claim 6, wherein the protective body (32) extends over and adheres to the peripheral portion (34, 36) of the outer major surface of each of said glass sheets (10, 12). A laminated glazing assembly according to any one of claims 1 to 8, characterized in that it comprises a plurality of electrical circuits (160) each having associated electrical conductors (22). A laminated glazing assembly according to claim 8, characterized in that it comprises two heating circuits (160) each having two connecting electrical conductors (22) extending beyond the edges (24, 26) of the glass sheets (10, 12). wherein one connecting electrical conductor (22) of the first circuit and one connecting electrical conductor (22) of the second circuit extend from the edges of the glassy -6GB 286724 B6 are in close proximity to each other and are protected by a common protective body (32). A laminated glazing assembly according to claim 9, characterized in that the two other connecting conductors (22) extend beyond the edges of the glass sheets (10, 12) at spaced locations and are protected by individual protective bodies (32). Method for producing a laminated glazing assembly according to at least one of Claims 1 to 10, characterized in that a mold is placed around the projecting portion of the connecting electrical conductor (22) and the adjacent portion of the glass sheet assembly (10, 12), and the polymer mass is poured or injected in a liquid state which solidifies in the mold cavity, whereupon the mold is removed and a glazing assembly with a protective body (32) with at least one connecting electrical conductor (22) is obtained. Method according to claim 11, characterized in that, before forming the protective body (32), said at least one electrical conductor (22) extends beyond the edges (24, 26) of the vitreous sheets (10, 12) and is to be encapsulated, connects to the corresponding insulated lead-in cable (30). Device for carrying out the method according to claim 11 or 12, characterized in that it comprises at least one mold comprising a cable passage which defines a cavity (42) for pouring or injecting a polymer mass, following a recess for inserting the edge portions of the vitreous sheets (10, 12) laminated glazing assemblies, and provided with a lead for the polymer mass. Apparatus according to claim 13, characterized in that a plurality of sub-molds are supported on a common frame, with spacing corresponding to the spacing of the individual electrical connection wires (22) of the glazing assembly to be encapsulated in corresponding protective bodies (32). Apparatus according to claim 13 or 14, characterized in that said at least one mold (40) is a two-piece mold defining a cavity (42) between the mold halves (40A, 40B) for pouring or injecting a polymer mass following the recess. for inserting the edge portions of the glass sheets (10, 12) of the laminated glazing assembly and provided with a feed channel (43) for the polymer mass.