WO1990011202A1 - Process for adhesively securing rear windows or windscreens in vehicle bodies, a device for implementing the process and window sealing strips - Google Patents

Abstract

The invention relates to a process for adhesively secuting rear window or windscreen panes (1) in vehicle bodies, especially in passenger and goods vehicles, where such a pane (1) is held in a strip (2) which, after the pane has been fitted, forms, together with the sheet metal body (3), with a strip (4) of a damp-curing adhesive or sealing compound and with the pane (1), a peripheral, annular hollow chamber (5) sealed especially against the outside; after the application of the strip of adhesive or sealing compound (4) and the fitting of the pane (1), water vapour is fed into the hollow chamber. This invention makes possible a sufficiently long processing time from application to skin formation to cope with possible interruptions in the manufacturing process while reducing the time from the completion of processing to the attainment of the initial solidity.

Description

"Method for gluing in rear or front windows in vehicle bodies, device for carrying out the method and strip for sealing these windows"

The invention relates on the one hand to a method for gluing in rear or front windows in vehicle bodies, in particular in passenger and truck vehicles, such a window being framed by a strip which, after installation of the window, together with the body panel, a strand of a moisture-curing adhesive or a moisture-curing sealing compound and the disk forms a circumferential annular cavity, which is closed off from the outside in particular. Such a method is known from DE 3409 960 AI.

The following problem arises in the industrial processing of these moisture-curing adhesives and sealing compounds, in particular in the case of production processes which are matched to the cycle time or driving speed of an assembly line: The curing speed of one-component adhesives and sealants is dependent both on the temperature and on the humidity of the surrounding area Air. These variables are therefore dependent on the current climate and are subject to seasonal fluctuations. This leads to problems, particularly in clock-oriented manufacturing processes, since the assembly process takes place on the one hand in a certain cycle time and therefore the reactivity of the sealing compound must be adapted to this cycle time and on the other hand disruptions in the production process up to the standstill of the production line are fully taken into account in the reactivity of the adhesives and sealing compounds used Need to become. It must therefore be possible to bridge longer waiting times without exceeding the processing time for adhesives and sealing compounds which have already been applied.

This problem becomes particularly clear in the following example. The front, rear and side windows of passenger cars and increasingly also of trucks and buses are glued with polyurethane sealants. These sealing compounds are one - component and harden by means of the air humidity. After the sealant has been applied, the pane is fitted and fixed. This process must be completed within 30 minutes of application, within the so-called skin formation time. After the skin has formed, the sealing compound has not yet reached the initial strength, but clean adjustment is no longer possible. After the pane has been fixed, the initial strength of the sealing compound must be achieved so that the panes cannot slip when the bodies are transported when the fixation is removed.

It normally takes 3-4 hours to reach the initial strength. The final curing and thus reaching the final strength takes several days. This relatively long time to reach the initial strength is disadvantageous since the fixing of the disks can be removed very late and other manufacturing steps can be carried out later accordingly. A test test for torsional stiffness can only be carried out after the Reaching the initial strength and after removing the disc fixation. If, on the other hand, other, more reactive sealant adhesives are used to reduce the time to reach the initial strength, the skin formation time within which the pane must be fitted and fixed is also reduced. However, a skin formation time that is too short means that a standstill in the production process leads to problems with adhesive that has already been applied, but not yet fitted and fixed pane. The adhesive or the sealing compound must therefore have a minimum open time, especially in damp, warm weather, and a maximum time for reaching the initial strength in dry, cool weather.

In addition to the proposal disclosed in DE 34 09960 AI to apply the adhesive strand in the form of two partial strands in two phases separated in time, further attempts are known to solve these problems. Instead of the one-component sealing compound described, a two-component sealing compound is proposed in DE-OS - 3407031. Single-component sealing compounds which can be pre-chemically hot have also been proposed (EP - 255 572 A1). The attainment of the initial strength in the known single-component sealing compounds depends on the climatic conditions. The course of hardening of two-component systems also depends on the temperature, and it is not known how the course of hardening can be influenced in a simple manner. The same applies to chemically pregelable masses. Here, too, the time remaining after the application allows compensation for any disruptions in the production process. However, the user would like the processing time to be as long as possible after the sealant has been applied and the initial strength to be reached quickly after processing. Furthermore, a ^" greater independence depending on the climatic conditions, i.e. air temperature and humidity.

EP 240 608 AI, DE-PS - 3545899 Cl, magazine "Chemical Week", 1985, pages 9-10, "Chemical Week", 1983, pages 52-54, DE-OS 3638449 AI are mentioned as further prior art.

The invention is therefore based on the object of creating a method of the type mentioned at the outset which has a correspondingly possible disruption to the production process, a sufficiently long processing time from application to skin formation, but a considerably shorter time from completion of processing to reaching it the initial strength. In particular, the time until the initial strength is reached should be freely controllable from the outside in a simple manner.

This object is achieved in a method of the type mentioned in the introduction of water vapor into the cavity after the application of the adhesive strand or sealing compound strand and the fitting of the pane. It is not necessary for the strand to be uninterrupted. In the series assembly of vehicles, it is customary to glue fully equipped windows, ie windows provided with cover and decorative profiles. The joint between the window edge and the body is covered by the profiles mentioned, which are also referred to here as strips. This creates a cavity between the sealing compound and the profile, which is ideally suited for steam treatments, since the cavity is shielded from the outside atmosphere by lips of the profiles. The gas space remaining in this way is relatively small. Therefore, only a little steam is required, which can also be used for networking through the cover. It is known from German patent specification 878 827 to allow moisture-curing adhesives to be accelerated by the presence of water vapor, but the use of this principle in the abovementioned so-called direct glazing is not known.

An advantage of the invention is that only short exposure times are required to obtain the required initial strength.

Furthermore, it is proposed that after the application of the

The adhesive and the joining of the parts to be bonded or after the application of the sealant to the adhesive or the sealing mass of water vapor at a temperature above 30 ° C, more particularly between 40 ° and 180 sondere ^β C, is allowed to act. In the method according to the invention, the partial vapor pressure of the water in the ambient air is essential. In the simplest case, the steam above boiling water is sufficient to increase the water vapor pressure. Surprisingly, it was found that within the typical skin formation time of about 30 minutes, steaming up to 50% of the final strengths can be achieved. In contrast, hardening in boiling water leads to a blistered and porous structure of the sealing compound and to damage to the substrate, although the sealing compound hardens completely.

It is also advantageous if water vapor is allowed to act on the adhesive or the sealing compound for a time between 5 seconds and 10 minutes, in particular between 15 and 60 seconds.

It is also proposed that water vapor be applied to the adhesive or sealing compound at a total pressure between 1 and 10 bar. absolutely has an effect. If steam treatment is possible in closed systems, the exposure time and thus the time to reach the initial strength can be shortened by an increased pressure and an increased steam concentration.

If the strip, that is the decorative profile, can also be plugged on after the pane has been installed, it is proposed that water vapor be allowed to act on the adhesive string without the strip being attached after the strip of adhesive has been fitted and the pane has been fitted. This bar is usually flexible.

To carry out the method, a device is proposed which has a frame made of a tube with nozzles for blowing water vapor into the gap, which frame is adapted to the gap between the window edge and the body panel. After mounting and fixing the pane, this frame can be brought close to the gap mentioned, so that the nozzles blow water vapor onto all parts of the adhesive strand at the same time. After a short exposure time, the strand of adhesive has received its initial strength; the frame and the fixation of the pane can then be removed.

Since, according to the invention, the initial strength is reached after only a short time, a test test for torsional stiffness which is customary in automobile plants can be carried out much earlier than using the known gluing method.

If the adhesive strand is to be treated with water vapor when the strip, ie the decorative profile, is attached, a strip, in particular a flexible strip with at least one inlet and outlet for water vapor, is proposed. Then through the inlet Steam is passed to achieve the initial strength, which then exits through the outlet.

In this case, it is particularly advantageous if the inlets and outlets are arranged in the part of the strip which is not visible in the installed state, and if the strip has a web pointing towards the body panel, through which the strip of the strip, the body panel, the Disc and the adhesive strand formed annular circumferential cavity between the inlet and outlet is interrupted. The inlets and outlets are therefore not visible when installed. Since they are consequently close to one another, the web mentioned ensures that the water vapor entering through the inlet flows through the entire cavity before it emerges again through the outlet.

In this case, it is advantageous if the web consists of two sections arranged at the opposite ends of the strip, which have surfaces that are suitable for gluing and face one another in the installed state.

It is also common for glass manufacturers to pre-coat the front and rear windows for the automotive industry, as described, for. B. is described in DE-OS 3409 960, DE-OS 3409 903 and DE-0S 36 38449 be¬. Before the prepared slices can be packed, the pre-coating must be fully hardened. The process according to the invention is also ideal here because curing in the autoclave under increased pressure and high atmospheric humidity, discontinuously or continuously in drying ovens saturated with water vapor, can be done much less time-consuming than curing in air. Hence the application of the above-mentioned method for curing the coatings of front and rear windows of automobiles.

Such an accelerated hardening or such a rapid attainment of the initial strength can also be used advantageously in the repair workshop if car windows have to be replaced. In fact, steam generators are available in practically every workshop, and in the case of the corresponding preparation of the profiles mentioned, steam treatment of already installed panes can also be used here.

Exemplary embodiments of the invention are explained in more detail below with reference to drawings. Show it:

Fig.l the strength as a function of time after certain treatment procedures,

2 shows a cross section through the cavity formed between the pane, decorative profile and body panel and

3 shows a section along line III - III of Figure 2.

1 shows the increase in the breaking strength of standard test specimens with single-component polyurethane sealing compounds after room temperature curing under normal climate (curve a), after 5 minutes of hot curing at 150 ° C. (curve b) and after 12 minutes or 24 minutes of curing reproduced in water vapor (curves c and d). The test specimens were produced between 0 and 10 minutes. The test specimens had a bonded area of 3 cm2. The required initial strength is approximately 100 N and the required final strength is 1200 N. It becomes clear that the desired initial strength can only be achieved in a short time when steam curing is used. The increase in temperature alone is hardly sufficient to obtain the desired initial strength in a short time.

FIG. 2 shows a section through the cavity formed by the pane 1, the body sheet 3, the adhesive strand 4 and the plastic strip 2. An uninterrupted strand of adhesive 4 is applied to the painted metal flange 3, on which the disc 1 is glued with its edge. The edge of the disc 1 does not lie close to the body panel 3, but forms a gap with it. This gap is covered by a cover or decorative strip, which, like the adhesive strand, runs around the entire edge of the pane.

FIG. 3 shows how the adhesive strand 4 can also be treated with water vapor when the plastic strip 2 is inserted. The strip 2 namely has two adjacent nipples, namely the inlet 6 and the outlet 7. Through these inlets and outlets, water vapor, as shown by the drawn arrows, can be flushed in and blown out again. The water vapor is pressed through the cavity 5 (FIG. 2) and thus acts on the adhesive strand 4. In order to prevent the water vapor from flowing out again largely through the outlet 7 after flowing through the inlet 6, a web 8 is provided between the inlet and outlet, as shown in FIG. From Figure 3 it is also clear that the web 8 consists of two sections, which are glued together with their surfaces 9 when the strip is glued together to form a ring.

The above-mentioned pre-coating of front and rear windows takes place in order to obtain a defined surface for gluing in the windows and to reduce the necessary pre-treatment of the windows in the automobile plant. It is precoated with the same sealing compound with which the panes are then glued in later. Since the precoating has to be fully hardened before the panes are packaged, it takes around 6 hours in the prior art for the glass manufacturer to pack the panes after coating. If, according to the invention, these disks are under increased pressure and increased air humidity in an autoclave treated, the maximum air humidity and the maximum pressure depend on the sensitivity of the panes and can be easily determined by experiment.

Reference list

disc

Plastic strip, flexible strip, decorative and cover profile

Body panel, painted metal flange

Adhesive strand

cavity

Inlet

Outlet

web

Surfaces

Claims

Claims Method for gluing in rear or front windows (1) in vehicle bodies, in particular in passenger and truck vehicles, such a window (1) being enclosed by a strip (2) which is put together after the window has been installed with the body panel (3), a strand (4) of a moisture-curing adhesive or a moisture-curing sealant and the washer (1) forms a circumferential annular cavity (5), which is in particular closed off from the outside, characterized in that after application of the adhesive strand or sealing compound strand (4) and the fitting of the disc (1), water vapor is brought into the cavity (5). 2. The method according to claim 1, characterized in that after the application of the adhesive and the assembling of the parts to be glued or after the application of the sealant to the adhesive or the sealant, water vapor at a temperature above 30 ° C, in particular between 40 and 180 ° C, can act. 3. The method according to claim 1, characterized in that water vapor on the adhesive or the sealing compound for a time between 5 seconds and 10 minutes, especially between 15 and 60 seconds. 4. The method of claim 1, d a d u r c h g e k e n n z e c h n e t that water vapor is allowed to act absolutely on the adhesive or the sealing compound at a total pressure between 1 and 10 bar. 5. The method of claim 1, wherein after performing the Ver¬ such a pane (1) is bordered by a strip (2), which can still be plugged onto the pane (1) after gluing, characterized in that after the application of the adhesive strand (4) and the fitting of the disc (1) without the strip (2) attached to it, water vapor can act on the adhesive strand (4). 6. Device for performing the method according to claim 5, g e k e n e z e i c h n e t d u r c h adapted to the gap between the edge of the window and body sheet (3), consisting of a tube frame with nozzles for blowing steam into the gap. 7. bar (2), in particular flexible bar (2) for sealing rear or front windows (1) against the corresponding Fahrzeug¬ body, in particular cars and trucks, characterized by at least one inlet (6) and one outlet (7) for water vapor. 8. A strip according to claim 7, characterized in that the inlets and outlets (6, 7) are arranged in the Te l of the strip, which is not visible in the installed state, and in that the strip (2) has a web (8) pointing to the body panel (3) ), through which the ring-shaped cavity between the inlet and outlet (6, 7) formed by the strip (2), the body sheet (3), the window (1) and the adhesive strand (4) is interrupted becomes. 9. The strip according to claim 8, so that the web (8) consists of two parts arranged on the opposite ends of the strip (2), which have surfaces (9) that are suitable for gluing and face one another in the installed state. 10. Application of the method according to claims 1 to 5 for curing the coatings of front and rear windows of automobiles.