NL192979C - A method of manufacturing a window assembly and window assembly obtained by that method. - Google Patents

Description

1 192979

A method of manufacturing a window assembly and window assembly obtained by that method

The invention relates to a method for manufacturing a window assembly, which is intended to be mounted in an associated frame member and comprises a plate of transparent material and a gasket, the method comprising the steps of being arranged in a number cooperating molded parts forming mold chamber of the sheet of transparent material, the molded parts comprising a gasket-forming surface which cooperates with a predetermined portion of the peripheral edge of the sheet to define a mold cavity for the gasket, injecting a polymer composition into the mold cavity which is capable of forming the gasket by hardening and adheres to the peripheral surfaces of the plate upon hardening in contact therewith and removing the assembly from the molding chamber after curing the polymer composition.

Such a method is known from U.S. Pat. No. 4,072,340. In this case, the packing is formed in situ by injection molding in a space which is partly determined by the edge of the (for instance 15 glass) plate and a frame. The gasket is formed from a molded material, such as polyvinyl chloride, which cures in the mold.

In such processes, the gasket-forming material is injected at particularly high pressures, which pressures can range from 350 to 1500 kg / cm2. In many instances, the plates used for the window assemblies contain relatively small irregularities in the otherwise flat surface, such as small ridges, formed therein during the manufacture of the plates. When such plates are used in the aforementioned injection molding process to form the gasket, there is a significant risk of breakage. The high injection pressures required in the aforementioned injection molding process require a significantly high back pressure (clamping force) to hold the mold surface against the surface of the plate. Since the steel surfaces of the molded parts do not adapt to the aforementioned irregularities (and cannot be designed thereon because of the irregular distribution of the irregularities), these high pressures often lead to breakage of the plate, especially in the areas where these irregularities.

The object of the invention is to improve on this and to that end provides a method of the type mentioned in the preamble, with the characteristic features that the pressure in the cavity into which the polymer composition is injected is controlled at a pressure which is sufficiently low remains so that the sheet material is not damaged during the molding process and that the temperature of the cavity, of the polymer composition and the amount of the injected polymer composition are controlled such that the polymer composition polymerizes after it has been injected and by the pressure resulting from the polymerization in intimate contact with the mold cavity boundaries in the plate and harden while in such contact.

In the method according to the invention, the plate of the window assembly is not subjected to high pressures, which considerably reduces the risk of breakage, while the gasket is still in intimate contact with the plate.

Preferably, the polymeric composition comprises an isocyanate and a polyol and forms a microcellular polyurethane elastomer upon polymerization and curing.

Preferably, the method of the invention includes the step of applying an ultraviolet absorbent coating to the outer surface of the gasket after removal from the cavity. This prevents attack by UV rays.

Preferably, prior to injecting the polymer composition, a primer coat 45 is applied to the surfaces of the transparent sheet on which the gasket is to be formed. This further enhances the adhesion between the gasket and the plate.

The invention further relates to a window assembly obtained by the method of the invention wherein the window assembly gasket includes a exposed mounting surface for placement against the framing member, the gasket further forming a free-standing finishing portion which is intended to be used during the outside of the window is located and extends inwardly from the sheet edge and also extends outwardly from the sheet edge to close the space between the sheet edge and the framing member during use and thereby contact the framing member.

A window assembly is hereby obtained in a simple manner that can be placed in the window frame of, for example, an automobile with little or no aids.

The invention is explained in more detail below with reference to an illustrative embodiment thereof shown in the drawing.

55 192979 2

Figure 1 is a rear view of a preformed window assembly according to the invention; Figure 2 is an enlarged partial sectional view of the assembly of Figure 1 according to It-II in Figure 1; FIG. 3 is an enlarged partial cross-sectional view of the peripheral edge portion of the window assembly of FIGS. 1 and 2 showing the application of a bead of adhesive prior to installation of the assembly; Figure 4 is a partial vertical sectional view of the window assembly of Figures 1, 2 and 3, after it is installed to close an opening, Figure 5 is a schematic showing the preferred process for producing the preformed window assembly of Figures 1 to and denoted by 4; Figure 6 is a more detailed schematic representation showing the basic components for the process of Figure 5; Figure 7 is a top plan view of a typical shape for producing the window assembly of Figures 1 to 4; Figure 8 is an enlarged partial sectional view of the shape of Figure 7 according to VIII-VIII in Figure 7; Figure 9 is an enlarged partial cross-sectional view of the vacuum head portion of the molding assembly of Figures 7 and 8 of IX-IX in Figure 7; and Figure 10 is an enlarged partial sectional view of the mold showing cooperative pads for supporting a glass sheet during the production of a window assembly according to the process of Figure 5; mold cavities in lower and upper mold parts are also shown.

Figures 1, 2, 3 and 4 show a preformed window or window assembly according to the present invention and produced according to the method thereof. More specifically, a preformed rear window 10 for insertion into a suitable opening in a vehicle body is shown. The vehicle body has a rear wall portion 12 which substantially defines the opening to be closed. The back wall portion 12 is typically formed from a sheet metal stamping piece and is suitably attached to a reinforcing member 14 by, for example, electrical resistance welding. Extending outwardly from the rear wall portion 12 and typically integrally formed therewith is a consecutive wall portion 16 defining, in conjunction with the rear wall portion 12, a cavity intended to receive the preformed window assembly 10. The wall portion 16 tapers into a fairly sudden bend, at which point the material 18 is contoured and it comes together as a whole with the sheet metal defining the silhouette of the associated vehicle.

The preformed back window assembly 10 includes an appropriately molded window material 20, which is typically formed from a sheet of optically transparent glass. A mount or gasket member 22 encapsulates the front, rear, and peripheral edge portions of the window material 20. The outer beaded or finishing portion 24 of the gasket 22, as clearly seen in Figure 4, covers a gap between the peripheral edge of the window material and the metal of the vehicle body surrounding the opening, the wall portion 16 of which is exemplary when the preformed assembly 10 is actually installed on the vehicle.

The portion of the mounting or gasket member 22, which extends within the finishing portion 24, surrounds the peripheral edge and the trailing edge of the window board material 20 and extends along its rear surface. A rib or sheet member 26 also occurs on the rear surface of the window material 20 which is spaced some distance within the end of the mounting or packing member 22. The area between the end of the gasket 22 and the rib 26 is intended to enclose a beaded edge of suitable adhesive material used in mounting the preformed window assembly. Furthermore, lips 28 are integral with the gasket 22 and the rib 26 and 50 the bridge member 30 between the gasket 22 and the rib 26 and lips 28. The lips 28 form applicators and adjusters which are of use during assembly of the assembly on a related vehicle and to hold the assembly in place until the related bonding material hardens to effect the desired bond between the preformed assembly and the joining portion of the vehicle.

55 The first operation in producing the rear window 10 involves thoroughly cleaning the front, rear and peripheral edges of the glass sheet material 20 to prepare the surfaces for adhering to the mounting gasket 22, the rib 26 and the associated lips 28. In certain instances 192979, it has been found desirable to include a layer 32 of opaque paint, glass chip enamel or the like which is applied to a portion of the back surface of the plate 20. The opaque material of the layer 32 is typically employed where it is necessary to obscure window mounting materials and structures as well as, for example, windshield wiper drive mechanisms, and in some instances where it is appropriate to protect them from ultraviolet radiation.

The next operation in producing the rear window 10 is to apply a primer coating to the pre-cleaned glass surfaces. Satisfactory results have been obtained by initially applying a layer 34 of a product commercially available under the designation "Betaseal, Glass Primer 435.18 Commercial Grade" from Essex Chemical Corporation, 10 Clifton, New Jersey, U.S.A. The glass bonding area is initially coated with the primer to form the layer 34 which serves as a coupling agent. The base material is a clear moisture-sensitive primer consisting of a gamma-amino-propyltriethoxilane, which promotes adhesion between other Betaseal products and glass.

After the application of the layer 34, a second primer coating 36 is applied over the layer 34.

Satisfactory results were obtained using a product commercially available under the designation "Betaseal, Glass Primer 435.20 Commercial Grade" from Essex Chemical Corporation. This material consists of a blackout primer that prevents ultraviolet attack from urethane sealants and adhesives and contributes to the rapid formation of a hydrolytically stable bond between the glass and urethane. About 20 minutes after the overlapping layers 34 and 36 have been applied, the assembly is placed in the mold cavity of a mold where the polyurethane gasket 22, the rib 26 and the lips 28 are produced; the mold is part of a device which will be described in detail later with reference to Figures 5 to 10. It is often desirable to apply a coating 38 to the outer exposed surface of the finishing portion of the gasket 22 before the is installed in a vehicle. The coating 28 may consist of a black urethane-based paint, such as one manufactured by PPG Industries, Inc., Pittsburgh, Pennsylvania, U.S.A. under the designation Purethane 700 HSE-848. The paint coating 38 is then baked at about 60 ° -65 ° C for about 20-30 minutes. The coating 38 is applied to protect exposed polyurethane gasket material from attack that would otherwise be caused by exposure to ultraviolet radiation as normally occurs in unfiltered sunlight.

The preformed window assembly can be installed in a suitable vehicle opening by applying a beaded edge 40 of adhesive material, for example a urethane sealant such as a sealant manufactured by the Essex Chemical Corporation and referred to as Betaseal 551.2, with water paste, on the circumferential rear edge surface between the packing member. 22 and 35 the spaced apart rib 26, adjusting the assembly in alignment with the vehicle opening and pushing the assembly into place. When the assembly is aligned with the vehicle opening, the tabs 28 are aligned with spaced co-operating openings 42 in the rear wall portion 12 and the associated reinforcement member 14 of the vehicle. The lips 28 have tapered tips to facilitate alignment. When the assembly is pushed into place 40, the tapered tip portions of the lips 28 pass through the openings 42 to snap them into locked positions where they hold the bead bead 40 in a compressed state (see Figure 4). Once the bonding material 40 hardens, installation is complete.

The preferred resins for use according to the invention consist of polyurethanes, preferably consisting of the linear or slightly branched polypropylene glycol polyethers and diphenylmethane-45 diisocyanates (MDI), which have been slightly modified either by carbodimide or by reaction of glycols to form isocyanate compounds , which are liquid at room temperature and low enough in viscosity to meet the process requirements of high pressure measuring and mixing equipment.

The resins are formulated to be polymerized upon injection into the mold cavity where polymerization and curing occur. The reactivity is controlled to provide sufficient polymerization and 50 cell stabilization, with a relatively short mold residence time sufficient for the assembly being produced. In this regard, it is noted that although hardening is possible at room temperature, the mold surfaces are typically maintained at 60 ° to 71 ° C, which temperatures resist layered glass products.

Referring now to Figures 5 through 10, it is seen that the device for producing the 55 assembly 10 includes a primer paint station 50 and a molding station 52 (see Figure 5), which includes a bulk storage area 54 comprising a stream consisting of a mixture of polyol, a chain expanding agent, for example ethylene glycol, pigment and a catalyst, and a separate stream of an isocyanate 192979 4 are supplied as required to a urethane measuring station 56. The isocyanate from the bulk storage tank 54 is supplied to a conditioning tank 58, while the polyol mixture is supplied to a tank 60. The outlets of the tanks 58 and 60 communicate with respective displacement cylinders or high pressure metering pumps 66 and 68 through the intermediary of respective recirculation pumps 62 and 64 to keep the material flowing at all times through the supply lines to a mixing head 74 and through recirculation lines back to displacement cylinders 66 and 68 feed. Heat exchangers 70 and 72 are employed in the system to maintain the desired reaction component temperatures. Constant motion and temperature control are essential to keep the various insoluble compounds in solution at temperatures at which the reactants remain inert and liquid, but will react quickly upon assembly.

An injection system is provided to inject a charge consisting of precisely controlled parts of the two circulating streams into the mold in a smooth, even flow. Measured charges of the two streams are supplied to the mixing head 74 from the outlets of displacement cylinders 66 and 68, respectively, through the action of pistons shown schematically. Injection into the mixing head 74 takes place under an applied pressure of the order of about 70 to 210 kg / cm 2. The two streams are mixed thoroughly in the mixing head 74. The mixture is delivered therefrom into an associated mold 76 at a pressure of about 3.5 to 7 kg / cm 2. Typically, the mold is kept at a temperature within the range of 60 ° -65 ° C.

The mold 76 consists of a bottom part 78 (Figure 7) and a top part 80. Suitable means, not shown, are provided to open and close the mold parts 78 and 80.

When the parts are open, the glass sheet 20 is placed on the lower part 78 so that portions of the rear surface of the glass come to rest on suitably adjusted pads 82. After the glass member 20 is properly positioned on the pads 82 of the lower molded part 78, the upper part 80 is lowered into place so that the outer peripheral edges of the mating parts 78 and 80 can be clamped together in metal-to-metal contact outside the mold cavity. The upper mold portion 80 of the mold carries pads 64 that function in conjunction with the pads 82 to press against the glass sheet 20 and enclose it within the mold cavity. The cavity of the mold 76 is larger than the molded glass plate 20 to avoid any glass-to-metal contact.

Vacuum cups in Figures 7 and 9 are shown in the top mold part 80 of mold 76 to raise the glass in conjunction with the mold part 80 when the molding operation is completed and it is desired to remove the glass sheet 20 from the mold 76 . The vacuum head mainly consists of a suction cup 86 which communicates with a source of underpressure through a vacuum line 88.

A plurality of movable mold segments, generally indicated at 90, are arranged at spaced points around the periphery of the mold corresponding to the positions of the lips 28. All of the mold segments are identical and are slidably received in respective recesses 92 located in the bottom molded part 78 are provided. The outer end of each segment 90 is formally attached to a block 94 operatively connected to the remote end of a reciprocating piston rod 96 of a conventional fluid-operated cylinder 98. The opposite or inner end of each segment 90 tapers into a contour corresponding to the outer profile of the gasket 22 and includes an extension 100 that forms the undercut in the lip 28. In operation, the piston rod 96 is expanded, advancing the molding segment 90 (Figures 8 and 10) in readiness to receive the charge packing resin. After polymerization and hardening of the packing material, the piston rod 96 and the movable molding segment 90 are retracted, 45 as shown by dashed-dotted lines in Figure 10, while retracting the extension 100 from the undercut portion of the lip 28, releasing the lip and releasing the rear window assembly for removal from the lower mold part 78 by the vacuum take-up of the top mold part 80.

After draining the assembly from the mold part 78, any excess gasket material or burr 50 is removed at a station 100, the assembly washed and dried at a station 110, and the paint coat 38 applied to the outer exposed finish of the gasket 32 and baked for hardening at station 120.

The following example is the best mode of operation currently envisaged and should be taken by way of example only and not in a limiting sense.

Claims (5)

192979 Example The surfaces of the top and bottom moldings 80 and 78 surrounding the mold cavity therebetween when assembled are treated with a solvent based mold release agent consisting of a mixture of waxes; the particular mold release agent is commercially available from the Park Chemical Company, Detroit, Michigan, U.S.A. under the trade designation PRC-789. A glass plate 20 was then suitably adjusted to the lower mold 78, after which the upper mold 80 was matched with the lower mold 78, and the two were clamped together. A batch consisting of one part by weight of a polyol composition and 0.63 parts by weight of an isocyanate was then driven into the mixing head 74 under a pressure of 177 kg / cm2 and hence in the form 77 at a pressure of about 3.5 kg / cm2 . The polyol and isocyanate streams were at a temperature of 43 ° C, while the mold 76 was at a temperature of 63 ° C. The polyol and isocyanate streams were mixed thoroughly in the cup 74 before reaching form 76. About one and a half minutes after the urethane composition was injected therein, the mold 76 was opened and the assembly 10 was removed therefrom. The resulting elastomeric packing 22 was microcellular, had a specific gravity of 1.07 g / cc, a hardness (Shore "A") of 90, a tensile strength of 106 kg / cm2, a percent elongation at break of 279, and a flexural modulus ( at 24 ° C) of about 250 kg / cm2®. The polyol composition used in carrying out the procedure described in the previous example consisted of 45 kilograms of a base polyol, namely a polyether trio! with 20 ethylene oxide "cover" with a molecular weight of 6000, sold under the trademark "Voranol" 5815 by the Dow Chemical Company, Midland, Michigan, USA, 4.5 kilograms of ethylene glycol, and 1.4 kilograms of 20% carbon black in polyol. The isocyanate used in practicing the procedure of the previous example consisted of a modified 4,4 'diphenylmethane diisocyanate sold under the trademark Rubinate LF 179 by Rubicon Chemicals Inc., Geismar, Louisiana. The aforementioned components were catalyzed by the addition of dibutyltin dilaurate, and a solution of triethylenediamine in dipropylene glycol. 30 Conclusions 1. A method of manufacturing a window assembly, which is intended to be arranged in an associated frame member and comprises a plate of transparent material and a gasket, the method comprising the steps of the molding chamber formed in a number of cooperating molded parts. arranging the sheet of transparent material, the molded parts comprising a gasket-forming surface which cooperates with a predetermined portion of the peripheral edge of the sheet to define a mold cavity for the gasket, injecting into the mold cavity a polymeric composition capable of forming the gasket by hardening and adhering to the circumferential surfaces of the plate in contact with it and hardening the assembly from the molding chamber after curing the polymer composition, characterized in that the pressure in the cavity in which the polymer composition is injected, it is controlled at a pressure that remains low enough for the sheet material is not damaged during the molding process and that the temperature of the cavity, of the polymer composition and the amount of the injected polymer composition are controlled such that the polymer composition polymerizes after it has been injected and comes into intimate contact by the pressure resulting from the polymerization with the mold cavity boundaries in the plate and hardens while in such contact. Process according to claim 1, characterized in that the polymer composition comprises an isocyanate and a polyol and forms a microcellular polyurethane elastomer upon polymerization and curing. 3. A method according to claim 1 or 2, characterized by the step of applying an ultraviolet absorbent coating to the inner surface of the packing after removal thereof from the cavity. Method according to claim 1 or 2, characterized in that prior to injecting the polymer composition, a primer coating is applied to the surfaces of the transparent plate on which the packing is to be formed. Window assembly obtained by the method according to any one of claims 1-4, characterized in that the 55 gasket (22) for the window assembly forms a exposed mounting surface (26, 28) for placement against the framing member (12, 16) and the gasket (22) further includes a exposed finishing portion (24), which is intended to be located on the outside of the window during use and extends inwardly from the plate edge 192979 6 and also extends outwardly from the plate edge to close the space between the plate edge and the frame member during use, thereby contacting the frame member. Hereby 4 sheets drawing