MXPA99008487A - Process for producing a curved laminated safety glass sheet - Google Patents

Abstract

This invention concerns a process for producing a curved, laminated safety glass sheet from a first curved glass sheet (1), a first laminated layer (2), a thermoplastic substrate sheet (4) with a biaxially drawn thin-layer system (3), a second laminated layer (5), and a second curved glass sheet (10) conforming to the first one. To avoid formation of folds in the substrate layer, the process has the following steps:(a) a prelaminated sheet consisting of the first laminated layer (2) and the substrate sheet (4) is superimposed with its laminated layer facing the first glass sheet, (b) a bend-resistant cover sheet (10) conforming to the first glass sheet (1) is superimposed on the prelaminated sheet, (c) the glass layer packet formed out of the first glass sheet (1) and the prelaminated sheet with the cover sheet (10) superimposed upon it is preliminarily bonded by removing the air and subjecting it to pressure and heat, (d) the cover sheet (10) is removed, (e) the second laminated layer (5) and the second glass sheet (10) are superimposed on the preliminarily bonded glass-film pocket, (f) the laminate so formed is preliminarily bonded by removing the air and subjecting it to pressure and heat, (g) the preliminarily bonded laminate is finally bonded into a laminated safety glass sheet by subjecting it to pressure and heat.

Description

PROCEDURE FOR THE MANUFACTURE OF ON ARCHED COMPOSITE GLASS SECURITY PANEL DESCRIPTION OF THE INVENTION: The invention relates to a method for manufacturing a composite arc-shaped glass panel from a first arched glass panel, of a first composite layer, of a thermoplastic carrier sheet provided with a thin layer system, of a second ca composed thus of a second panel of arched glass that s adjusts to the first one. Safety glass panels composed of the above structure are increasingly used as sun protection, especially for motor vehicles. For this purpose the thin layer system on the carrier sheet typically consists of up to three layers of noble metal, preferably base of silver, which are embedded in dielectric layers (U 47 99 745 Al). By using a thermoplastic sheet as carrier for the thin layer system it is achieved that the carrier sheet can be adjusted to the arc of the glass panel as a step for the thermal treatment necessary for the bond or composition. The conformation of adjustment of the carrier sheet is favored, because biaxially stretched thermoplastic carrier sheets are used. Indications for the selection of suitable carrier sheets can be taken, for example, EP 00 77 672 B2 and EP 0 457 209 A2. Especially ref; 31257 suitable biaxially stretched carrier sheets for the safety composite glass panels are subject of the above PCT application EP 96-04018 ((WO 97/10099) of Flachgla Automotive GmbH). The two composite or bonding layers ensure that an adhesive bond of the carrier sheet is verified with the glass panels and give the laminate glass security properties. For the manufacture of glass panels of the above structure, it has already been proposed to form a preliminary laminate of the sheet from the first bonding layer, in which the carrier sheet is provided with the thin layer system as well as the second bonding layer. , where the sheets are pressed together, the air is withdrawn and previously applied with heat (EP 0 535 128 Bl). The sheet pre-laminate formed is placed between the two glass panels, where the lamination of glass panels and sheet pre-lamination is subjected to a process of air removal as well as a pre-joining process. The laminate is then joined at an elevated temperature and under high pressure to obtain the composite safety glass. This form of procedure has been found suitable for slightly or slightly arched glass panels. With strong bends, especially complex bows, it is frequently encountered in the practice to form folds, mainly in the edge area, on the carrier sheet, also indicated as edge ripple.

To solve these problems, different measures have already been proposed, in which a pre-laminate of at least one joining layer as well as the carrier sheet is suitably pre-formed in a special device (WO 94/04357). The procedure is complicated and requires a specially made mold for each type of panel. Deviations forced by the tolerance of the glass panels from the payroll form can lead in the known processes to faults d adjustment that influence the optics of glass panels d safety compound, in the union between the glass panels the pre-laminate of the leaves. The invention aims to present an improved manufacturing process for safety glass panels composed of the above structure, with which the presentation of pleats in the carrier sheet during manufacture and especially during the manufacture of panels can be better avoided. of safety glass compounds of complex type without formation of folds worthy consideration, in any case in the visible area of the panel. The composite safety glass panel should be broadly free of corrugated deformations of the carrier sheet provided with the thin layer system that cause optical disturbance mainly in the reflected light but also in the light that passes through. To solve this problem he proposes the invention or procedure, which is characterized by the procedural steps (a) - (g) mentioned in claim 1. The invention is based on the surprising knowledge that with the help of a multistage process of pre-union final union, in which firstly a pre-laminated prime pre-laminate is fabricated from a first arched glass panel, first joint layer and carrier sheet with the help of an arched and rigid flex panel covering the carrier sheet before the second one is pre-joined With the joining cap and the second panel first with the prelaminate, then all the laminate is finally joined, a formation of dislocating folds in the carrier sheet can be sufficiently avoided. The invention is especially suitable for the production of complex-shaped arched composite safety glass panels for automobiles with a transverse flexure of 10 m and more. The transverse bending (gauge height) is given in a standard manner for the area of the transverse central axis which is in the normal case the axis of symmetry in the windshield or rear panele. Precisely, it is possible, if necessary, with bonding layers formed in situ to be worked from bonding materials into a flowable state, placed on one of the glass panels or the carrier sheets, for example with casting resins or with materials of union placed in solution fluids in appropriate solvents. As binding layers, however, it is possible within the framework of the present invention to use, preferably, surface-treated, surface-treated sheets of grain of a usual thickness, that is, typically 0.38 0.76 mm from materials known to the glass manufacturing technician. compound. Carrier sheets are preferably considered as those indicated in the PCT application EP-96-0401 (WO 97/10099). However, the present invention is not limited thereto. The decisive criterion for the selection of coarse material for a carrier sheet in dependence with the invention is its compatibility with the bonding or composition layers and with the processes of prior and final binding for the use as well as the presence of a behavior d shrinkage to the adequate heat, which allows a conformation d adjustment of the carrier sheet in reference to the manufacture of composite safety glass panels. Here, carrier sheets biaxially stretched are basically preferred. However, in the context of the invention, depending on the bending of the glass paneles in the individual case, only weakly stretched carriers can also be used. This is especially true when the process step (c) was carried out at a relatively high temperature. The carrier sheets must have sufficient light transparency for each application, be suitable as carriers for the thin cap system and have a good adhesion on both sides to the joint cap. Preferably, a leaf pre-laminate is used in the process according to the invention, in which the thin layer system of the carrier sheets is limited to the first connecting layer. The thin-film system is thus protected against damage in reference to the manufacturing process, especially in steps (b) and (e). For the manufacture of the prelaminate sheet, for example, the carrier sheet can be removed from a deposition roll and with the application of pressure and heat pre-assembled from the simultaneous or previous air with the first union layer formed of a joining sheet. For the flexible rigid cover panel can be used basically all non-folding material with the carrier sheet, tolerable with the carrier sheet of the pre-laminated sheet and stable in its form at the applied temperatures. understands that the surface of the cover panel that borders the carrier sheet should be as smooth as possible. In this way, in the heat treatment of the process step (c), the same thermal conditions can be created below and above the leaf pre-laminate. Basically it is possible to use multiple times one and the same glass panel as the cover panel. It has a special advantage, however, that the second glass panel of the composite safety glass panel to be manufactured was used as a cover panel for the procedure step (b) - (d) Especially when, as is usual in the manufacture composite safety glass panels both glass panels are bent or arched together, it being possible to achieve, that the bends of the cover panel and the first glass panel are well determined from each other, so that the cover panel in the process step (c) on its surface resting tightly on the carrier sheet sufficiently prevents the formation of folds. Especially when the process step (to be carried out at relatively high temperatures), it is recommended that the cover panel be provided before laying on the sheet pre-laminate with a thin separating layer that decreases the adhesion. The carrier sheet should preferably be placed on the first glass panel, preferably in such a case that the carrier sheet should adhere to a point so strong that, in process steps (c) or (d), particles of the carrier sheet, which could lead to optical changes in the glass panel d.It has been presented with this as especially advantageous that a thin separation sheet, which does not adhere to the carrier sheet under the conditions of step d process (c) As separating sheets according to the invention, the use of carrier sheets made of PET is preferred, example polyethylene (PE) or PET sheets without cover as well as acetate sheets. These materials are of a good relative price with sufficient efficiency, so that the application does not present a significant increase in cost. The use of sheets as a separating layer also has, in contrast to the dust or liquid separator layers, the advantage of a relatively simple handling when placing before and after the process step (c). It is understood that the separating layer (separating sheet) must have a uniform thickness over the entire surface, so that in the process step (c) the carrier sheet does not deform unevenly. The first and second joining layer preferably consists of polyvinyl butyral (BPV) or ethylene acetate copolymer (EVA). Especially for this bonding material it is important that if step d process (c) takes place at a pressure of a maximum of 2. bar and a temperature of at least 10 degrees, preferably at least about 50 degree below the temperature maximum used in the procedure step (c). If by a corresponding selection of material is ensured, that the carrier sheet can slide well along the cover panel and on this when the cover panel rises has not been punctuated, the temperature of the process step is adjusted (c) preferably under the temperature of the final joint d according to step (g) of the process, so that the carrier sheet is plastically deformed and the flexing of the first glass pane and the cover panel can be permanently adjusted. Since the desired adjustment deformation d the carrier sheet is fixed by the pre-bonding process first in which the sheet pre-laminate is pre-bonded with the prime glass panel, thus the formation of folds can be minimized in the remaining steps of the procedure. Surprisingly it is possible with the manufacturing process according to the invention to reduce strongly the so-called orange peel effect with respect to the bonding methods hitherto applied. The effect of orange peel visible mainly in the reflection is caused by the lifting of the surfaces of the binding sheet, necessary to remove the air, which in reference to the joining process is formed as irregular elevations and subsidence in the carrier sheet provided with the thin layer system. This undesirable effect is supposed to be markedly reduced because, the carrier sheet coated in the process step (c) is pressed against the surface and non-deformable of the rigid deck panel when flexed and the rough surface of the air removal of the first limiting bond layer can not be formed or applied in an important manner on the carrier sheet, so that the composite safety glass panels according to the invention enjoy a good reflection optics, hitherto not achievable. With the invention, in any case, if a biaxially stretched carrier sheet is used, the temperatures of the pre-joining treatment of the process steps (c) and (f) below the maximum temperature of the final joint according to step of procedure (g) precisely of at least about 10 degrees. Co this is achieved that the carrier sheet also after the two thermal treatments of pre-union still has a capacity of thermal shrinkage, which takes care that the light deformations of the carrier sheet that exist in case, before the final union is can correct in the final unió. Preferably, the process steps (c) and (f) are conducted in such a way that the remaining shrinkage capacity of the biaxially stretched carrier sheet is still approximately 10%, preferably at least 20% of the original, of the value that It is produced by biaxial stretching and thermofixation. An adhesion of the biaxially stretched PET carrier sheets in the cover layer or panel formed by the glass panel, can also be carried out without a separating cap and thus saving expenditure, if the temperature in the process step (c) is at least 50 ° below the final temperature which is approximately 125 ° C, that is, it remains at 75 ° C. In this case, the adjustment conformation of the carrier sheet adjusted to the correction biaxial stretch at elevated temperature presents, in the process step (c) still a considerable fraction of elastic volume, so that until the process step (f) in the final union (procedure step (g)) will be made last plastic deformation of the carrier sheet, so any failure may lead to the formation of lighter plies or insignificant orange peel effects m. It has been reported that composite safety glass panels with common measures in the automotive cam as a rule are fabricable either at low temperatures in the process step (c) and with the use of a separating layer. The panels with a transverse bending of more than 14 mm are on the contrary preferably subjected to a higher temperature using a separating layer in the step (c) of the process. Step (f) is carried out in a thermal treatment furnace or in a autoclave preferably at a pressure of a maximum of 2.5 bar and a temperature of at least 10 degree below the maximum temperature applied in the final connection according to the process step (g). The final connection according to the procedure step (g) is carried out at a temperature d approximately 115-135 ° C and a pressure of a maximum of 13 ba In the pre-joining process of step (c) and (f) it is used c special advantage the process of joining of lips in itself known by the manufacture of composite glass, in which around d package of cover panel or - sheets - glass or of the pack glass - leaves - glass a lip profile is arranged closed for a sub-pressure system, the air is sucked from the intermediate space between the layers not yet joined, these layers pre-join each other by means of the application of a thermal treatment with a duration of half an hour. But it can also work with another known process of pre-joining, for example, with pre-bonding laminate or with an empty drying. For the final connection according to step (g) the pre-joined pack of glass panels, joining layers and carrier sheets is subjected to a known treatment in the autoclave as practiced in the manufacture of composite glass. In the following, the invention will be explained in more detail with reference to the drawings, in which: FIG. 1 shows a representation in principle of the essential steps of the method according to the invention according to a first embodiment and to the process steps of the second example realization, which coincide with the first example of realization FIGS. 2 a-c represent in principle the essential steps of the method according to the invention according to the second embodiment: EXAMPLE 1 A PVB bonding sheet (2) on both sides grained d 0.38 mm thick of the Firm Monsanto and a carrier sheet PE (4) with a coating of protection against the sun altament transparent to light with a double layer of silver (product indication XIR 75) of the firm South all as a system of thin cap (3) are pulled by rollers, at a temperature of 60 80 ° C with sausage of the thin layer system (3) between the carrier sheet (4) and the PVB bonding sheet (2) between a pair of rollers to be joined in a sheet pre-laminate. Partial adhesion with air withdrawal and then cut to the appropriate measure. The PET carrier sheet (4) had been biaxially stretched and thermofixed before coating. Stretching and coating were carried out in accordance with the PCT application EP 96 04018 (WO 97/10099 under conditions, in which the PET carrier sheet (4 after coating and before the manufacture of the pre-laminated sheet present the following behavior) d heat shrinkage: the coated PET carrier sheet (4) was shrunk during a dive of approximately 20 seconds in a liquid bath at 120 ° C polyethylene glycol (molecular weight approximately 400) in the plane of the parallel sheet perpendicular to the longitudinal stretch Each time and approximately 0.4% The shrinkage measurement is carried out so that, between the jaws of a longitudinal measuring device, the two ends of a sheet strip of length 150 mm and a width of 15 mm are fastened. The strip of sheet is measured before immersion in the tempered bath and after the end of the heat treatment the same starting temperature. to the percentage length variation as shrinkage measure in the shrinkage temperature and the indicated dwell time. The coated PET carrier sheet (4) presents for the safety position with sufficient adhesion to the PVB joining sheet (3.5) on both sides, a surface energy of more than 40m_T / m2. The pre-laminate manufactured as described above is placed with the side of the binding sheet free of creases on the concave side of a first complex arched glass panel (1) placed on a horizontal setter. The panel with a thickness of 2.1 mm (step of procedure (a)). The glass panel (1 of approximately 1.50 m long and 0.90 m wide already had arched or flexed in the longitudinal direction as well - albeit to a small extent - in the transverse direction, its point height or gauge. in the longitudinal direction it was 10 cm, while in the transverse direction it was 12 mm, along its edge, a width of 25 mm was pressed (not shown) and opaque colored ceramic protective strips were provided. It was placed on the glass-sheet pack so that, as shown in Figure 1, as a covered cover panel, the glass panel (10) of a thickness of 1.5 mm of the composite safety glass pane which has manufacture, which previously, together with the first glass panel (1 had been folded in a bending process by gravity (process step (b)). Around the edges of the package pane of cover-sheet-glass was put for the vacuum a profile d vacuum lip (11) by means of which in connection with it s sack the air for approximately 20 minutes (Fig lb). The package to which underpressure was applied both before and after was heated in a heat treatment oven at approximately 75 °, a half hour was left at that temperature and then cooled to room temperature (process step (c)). After the removal of the cover panel 10 (process step (d)) it was recognizable that the PET carrier sheet (4) had been adjusted to the shape of the first frosted glass panel (1). On the uncoated side that remains free of the PET carrier sheet (4) of the pre-laminate thus formed glass-leaf, the next step was carried out, represented in Figures 1 and 1, firstly a second PVB (5) granulated bonding sheet 0.38 mm thick of the Monsanto Firm (Fig le) and the glass panel (10) previously used as a cover panel (Figure 5). ld, procedure step (e)). The edges of the PVB bonding sheets (2, 5) and the PET carrier sheet (4 protruding from the edge of the glass panels (1, 10) s cut with a knife around the edges of the panels as in The first pre-union process, placed around a closed lips profile (11) of sub-pressure system in order to remove the air.In the following process of removing the air, the lip profile was applied approximately 20 minutes with He subpressed and he emptied the glass-sheet-glass package (Fi le), then pressed it maintaining the underpressure in a heat treatment oven with the help of a thermal treatment for half an hour at a maximum temperature of about 100 ° ( procedure step (f)). After an intermediate cooling by time, the final joining process was carried out in an autoclave with a heating of the glass-leaf pre-assembled packet at approximately 125 ° and a pressure treatment of up to 13 bar (step of procedure (g)) • The composite and finished safety glass panel after removal of the autoclave was subjected to u control of the reflection and transmission optics. Precisely s determined within the edge of the panel covered by the strips d protection in sight, in some areas a slight ripple of the PET carrier sheet. But in the area of visibility was the PET carrier sheet (4), free of folds. It shows only a very insignificant effect of orange peel at the naked eye. In general, the glass panel corresponded to the strict requirements on the front and rear panels of automotive vehicles in what refers to the safety properties in both the reflection and transmission optics. EXAMPLE 2 Correspondingly to Example 1, first a sheet pre-laminate was made with a PVB granulation sheet on both sides of a thickness of 0.38mm (2) and a carrier sheet (4) PET with a layer of sun protection highly transparent to light as a thin layer system (3). The pre-laminate is bent with the side of the sheet of folds-free connection on the concave side of a complex on a first glass panel (1) fixed on a horizontal support with a thickness of 2.1 mm (process step (a)). The first glass panel (1) had the same dimensions as e of example 1 and was also bent in the longitudinal and transverse directions. Its gauge height or length in the longitudinal direction was as in example 1 d approximately 10 cm and in the transverse 15 mm. A burnt opaque protective strip with a width of 25 mm (not shown) is pressed along its edge. In contrast to example 1, an uncoated PET separating sheet (6) with a thickness of about 25 microns on its carrier sheet side was arranged as a separate layer for process step (c) together with the leaf pre-laminate. On the glass sheet package thus formed, a second glass panel (10) of a thickness of? .5mm, which had previously been folded together with the first glass panel (1) in a bending-by-gravity process, was placed as the cover panel. adjusted mode (Fig. 2a, procedure step (b)). Around the edge of the cover panel pack - sheet - glass rolled up for vacuum removal a vacuum lip profile (11) through which the package air is removed last approximately 20 minutes (Fig 2b). The package submitted as soon as as after to a sub-pressure, heated to approximately 115 ° C, for about 30 minutes it was left at that temperature, then it was cooled to room temperature (step procedure (c)),. After the removal of the cover panel (10) (process step (d)) and separating sheet P (6) was recognizable that the PET carrier sheet (4) had been adjusted folds-free to the shape of the first glass panel (1). On the uncovered free side of the PET-coated sheet (4) of the pre-laminate thus formed glass-sheet in the next step was placed a second PVB bonding sheet (5) a thickness of 0.76 mm granulated with a screen protection coloring wedge from the Monsanto Company (Fig 2c) and above the glass panel (10) previously used as a cover panel, from which the separating sheet PE had been removed (Figs le and ld, process step (e)). The protruding edges of the PVB bonding sheet (2,5) and the PET carrier sheet (4) of the edge of the glass panels (1, 10) are cut with a cutter. Around the edge of the panels, a lip profile (11) connected to the sub-pressure system in order to remove the air (Fig le) was placed as in the previous previous joining process. In the following process of removing the air was applied by the empty lip profile (11) and the glass-sheet-glass package air was removed. Then, maintaining the underpressure was pre-joined in a heat treatment furnace with the aid of a half-hour heat treatment at a maximum temperature of 100 ° C (process step (f)). Here after an intermediate cooling, the final bonding process in an autoclave was followed by heating the pre-package I glass-sheet- pack at approximately 125 ° and a pressure treatment up to 13 bar (process step (g)). The composite and finished safety glass panel was removed from the autoclave and subjected to a control of the optical reflection and transmission qualities. In the visible joint field the coated PET carrier sheet (4) is free of creases. Virtually no orange peel effect was recognizable. As a whole, the vidri panel met the strict requirements for rear end panels in automotive vehicles with regard to the visibility properties and the transmission reflection optics. EXAMPLE OF COMPARISON A safety glass panel composed of the same measurements, the same bending and the same components of Example 1It was manufactured, where firstly in Example 1, a first bonding sheet (2) and a coated PET carrier sheet (4) were manufactured and laminated pre-treated and vacuum-treated. The pre-laminate thus formed s placed with its side of tie layer on the first panel d glass (1). A second sheet of union (5) PVB of a thickness of 0.38mm of the Monsanto Firm was placed on the pre-laminate. The glass-sheet package was completed with the second glass panel (10) duly folded, after removal of the air and analogously to the process step (f) according to Example 1, they were then pre-packed corresponding to the step of procedure (g) definitely joined. After the pre-bonding process, a series of creases had formed in the edge area on the PET carrier sheet (4), which reached the panel visibility area. Those folds were not removed in the next final joining process, so that the composite safety glass panel was not applicable as a motor vehicle panel due to the lack of optical quality. The joint safety glass panels according to example 2 and the comparison example were subjected to a measurement of their reflection interruption force in the visible field. The measurement was carried out in such a way that the reflection was diverted to the rear side of the panel, so that only the interruption force of reflection caused by the front side of the panel, relatively insignificant of a few millidiopters, was measured, as well as the on the relatively high PE coated carrier sheet. The following values were obtained.

It is understood that in the measurement of the panel of the comparative example only areas of the panel free of creases were evaluated, to guarantee a comparison of the measurements. The results of the measurement show that with the manufacturing process according to the invention, it is not only possible to avoid the formation of transverse folds of the coated carrier sheet, but also to drastically improve up to one third (expressed in the measured magnitude of the reflection interrupting force of the reflection optics of the panel with respect to the previous state of the art due to a decrease in the effect of orange peel d.The application of the manufacturing method of the invention allows the manufacture of glass panels of Safety of composite sheets with embossed coated carrier sheets with an optical quality of previously unreached reflection It is noted that in relation to this date, the best method known to the applicant to carry out the said invention is the conventional one for manufacturing objects or products to which it refers.

Claims (13)

1. CLAIMS Having described the invention as above, property claimed in the following claims is claimed: 1.- Procedure for the manufacture of an arched composite safety glass panel made of a first arched glass pane, of a first thermoplastic carrier sheet provided with a thin layer system, of a second joining sheet as well as of a second arched glass panel of adjusting man, with the following procedure steps: a) A consistent pre-lamination of the first joining layer and of the carrier sheet is placed with the joining layer side on the first glass panel; b) an arched roof panel fitting with first glass panel is placed over the pre-laminated sheet; c) the package formed of the first sheet and glass pre-laminate panel is subjected to vacuum and pressure application is pre-attached; d) the cover panel is removed; e) the second joining layer and the second glass panel are placed on the pre-attached glass-sheet package; f) the laminate thus formed is subjected to vacuum and pressure application is pre-linked; g) the pre-bonded laminate is finally joined by applying pressure and heat forming a composite safety glass panel.
2. 2. Method according to claim characterized in that a carrier sheet stretched biaxially is used.
3. 3. Method according to claim 1, characterized in that a sheet pre-laminate is used, in which the thin-film system of the carrier sheet limits with the first joining layer.
4. 4. Method according to one of claims 1 to 3, characterized in that, the second pane of glass is used as a cover panel.
5. 5. Method according to one of claims 1 to 4, characterized in that the cover panel d is provided before laying on the sheet pre-laminate with a thin separating layer that decreases the adhesion. 6. - Method according to one of claims 1 to 5, characterized in that, the sheet carrying the sheet pre-laminate before being placed on the cover panel d is provided with a separating sheet that decreases the adhesion. Method according to one of claims 1 to 5, characterized in that a separating layer is used as separating cap, which under the conditions of the third process step does not adhere to the cover panel or the carrier sheet . 8. Process according to one of claims 1 to 7, characterized in that the first and the second joining layer consist of polyvinyl butyral ethylene vinyl acetate copolymers. 9. - Method according to one of claims 1 to 8, characterized in that a carrier sheet made of polyethylene terephthalate is used. 10. - Method according to one of claims 2 to 9, characterized in that the steps of the process (c) and (f) are carried out at a temperature, which is so below the maximum temperature of the final joint, that the ability to shrink the heat of the carrier sheet in both directions of stretching in process step (g) is still at least 10% preferably still less than 20% of its ability to shrink to heat before the process step ( to) . ll. - Method according to one of claims 10, characterized in that the process step (c) takes place at a pressure of at least 2.5 bar and a temperature that remains at least 10 degrees, preferably 50 degrees below the maximum temperature used for the final joint according to the procedure step (g). 12. Process according to one of claims 1 to 11, characterized in that the process step (c) is carried out at a maximum pressure of 2.5 bar and a temperature that remains at least 10 degrees below the temperature used in the final union in the procedural step (g). 13. Method according to one of claims 1 to 12, characterized in that the fine connection is carried out according to process step (g) at a temperature of approximately 115-135 ° C and a maximum pressure d of 13. Pub.