CN112399914A

CN112399914A - Method and device for producing thermoplastic intermediate layer films for composite glass sheets

Info

Publication number: CN112399914A
Application number: CN202080001411.6A
Authority: CN
Inventors: S·吉尔; R·坎南吉泽; F-J·拉茨
Original assignee: Saint Gobain Glass France SAS
Current assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Priority date: 2019-06-14
Filing date: 2020-06-10
Publication date: 2021-02-23
Also published as: DE202020005520U1; WO2020249590A1

Abstract

The invention relates to a method for producing a thermoplastic interlayer film (F) for a composite glass pane, comprising the following steps: heating the interlayer film by rotation of the heating roll (2) and subsequently stretching the interlayer film over a stretching cone or stretching roll (3) in order to guide the heated interlayer film through the stretching cone with a predetermined pressing force and thereby process and configure the heated interlayer film for installation into the composite glass sheet, wherein the interlayer film is not conveyed between the heating roll (2) and the stretching cone or stretching roll (3) to a pair of pressure rolls, wherein in the heating step on the heating roll, thermal energy and/or a pressing force is additionally applied to the surface of the interlayer film facing away from the heating roll.

Description

Method and device for producing thermoplastic intermediate layer films for composite glass sheets

Technical Field

The invention relates to a method for producing a thermoplastic interlayer film for a composite glass pane, comprising the following steps: the interlayer film is heated by the rotation of the heated roll and then stretched over a stretching cone or stretching roll. The invention also relates to a device for carrying out the method.

Background

Composite glass sheets are used in large quantities in vehicle manufacturing, particularly in the automotive industry, but also in the manufacture of structural elements for buildings and interior installations. To produce the required pieces, high-volume production facilities are used for the required components and for mounting and configuring the glass units. Parts and installed glass units are processed or installed in facilities at high pass through speeds or very short cycle times, and optimization of the process flow is an important source in the industry to increase productivity and reduce costs.

The composite sheet comprises at least one outer sheet and an inner sheet, which are connected to each other by an intermediate layer. The composite sheet is configured for use in separating an interior space from an exterior environment in, for example, a window opening of a vehicle, building, or room. By an inner sheet is meant a sheet facing the inner space within the meaning of the present invention. With exterior sheets is meant sheets facing the outside environment. The thermoplastic interlayer serves to join the two sheets, as is common in composite sheets.

The outer and inner sheets are preferably made of glass. In principle, however, the outer and inner sheets can also consist of plastic. The thickness of the outer and inner sheets can vary widely and is therefore matched to the requirements in the individual case. The outer and inner sheets preferably have a thickness of 0.5mm to 5mm, particularly preferably 1mm to 3 mm. The sheet may be transparent or may also be coloured or dyed.

The outer sheet, inner sheet and/or intermediate layer may have suitable coatings known per se, such as anti-reflection coatings, anti-adhesion coatings, anti-scratch coatings, photocatalytic coatings or sun-protection coatings or low-emissivity coatings. The outer sheet and the inner sheet are connected to one another by lamination to a thermoplastic plastic film, in particular a PVB (polyvinyl butyral) film, or also to a plurality of such films. The thickness of the film in the composite sheet is typically in the range between 0.3 and 1mm, in particular between about 0.5 and 0.8 mm. Subsequently, such a film is referred to as an interlayer film.

In order to process the interlayer film in its properties and at the same time to configure it for installation into the composite glass pane, i.e. to enable cutting into the shape of the composite glass pane and stress-free installation into the composite glass pane, the film is subjected to a method comprising the method steps mentioned at the outset.

International patent application WO 2017/153167 a1 shows a method for producing wedge-shaped, thermoplastic plastic films, in which plastic films unwound from a supply roll are first fed to a heating roller and then further transferred to two heated pressure rollers. The two heated pressure rollers have a temperature above the glass temperature and below the melting temperature of the plastic film. The clear width between the two pressure rollers corresponds to the cross-sectional profile of the plastic film to be produced, which is wedge-shaped. The plastic film is then conveyed to a stretching apparatus.

In this method, it has been found that, in order to achieve a high throughput rate and optimum use possibilities for the production of films, there is still a need for improvement even in the case of complex shaped composite glass sheets. The object of the present invention is therefore to provide an improved method of the type described above and a correspondingly improved device.

Disclosure of Invention

This object is achieved in terms of its method by a method having the features of claim 1 and in terms of its apparatus by an apparatus having the features of claim 8. Advantageous developments of the inventive concept are the subject matter of the respective dependent claims.

The invention comprises the idea of providing, within the scope of the method control known per se, measures for improved preheating of the film in the stage of processing and pre-configuration of the interlayer film by means of a drawing cone (or simply a drawing roller which may also be substantially cylindrical). In principle, the concepts and inventions described and the essential features thereof are also suitable for producing or processing other thermoplastic plastic films, i.e. those which are not provided for installation into a composite pane.

According to the inventors' knowledge, a temperature profile which is as uniform as possible not only in the thickness of the interlayer film but also in the length and precisely achieving the required drawing temperature are important prerequisites not only for providing an interlayer film which is optimally matched to the complex composite glass sheet geometry, but also for achieving as high a speed of penetration as possible in the installation. The inventors therefore propose a measure to additionally input thermal energy in the preheating step. According to a further concept of the invention, additional heat input and/or additional pressing forces (in addition to the pressing force provided by the normal guide or deflection roller) are provided exclusively on the heating roller for this purpose. The additional pressing force improves and, if necessary, evens out the thermal contact of the film with the surface of the heated roller.

In the first embodiment, it is provided that the additional heating energy and pressing force are applied by a plurality of auxiliary heating rollers arranged on partial areas of the periphery of the heating roller. This means in terms of the device that the auxiliary heating roller mentioned is installed in the device distributed over a partial area of the periphery of the actual heating roller.

In another embodiment of the invention, additional radiant heat may be achieved by irradiating the interlayer film with IR radiation (which also includes broadband radiation having IR or NIR components). The radiant heat may be applied in particular in a plurality of spaced apart radiation-active zones, and the pressing of the interlayer film onto the periphery of the heating roller is carried out between the radiation-active zones, respectively. It is to be understood that at least one source of thermal radiation, in particular a plurality of IR radiators arranged at a certain distance, is provided in a device suitable for carrying out the method.

In order to additionally ensure a desired better contact of the intermediate layer film with the surface of the heating roller, in particular when passing at high transport speeds, it is also possible to position pressing elements, in particular pressing rollers or pressers, on the periphery of the heating roller in addition to the heat radiator or radiators.

In yet another embodiment of the present invention, instead of a plurality of auxiliary heating rollers, a single auxiliary heating device having a heated surface corresponding to the surface of the heating roller, i.e., in the shape of a circular arc, and subsequently referred to as a heated roller shoe (Walzenschuh) is disposed on a partial area of the periphery of the heating roller. The roller shoe and the outer peripheral section of the heated roller together form a peripheral gap through which the polymer film to be processed passes. The polymer film is heated continuously from both surfaces in the extended gap, which provides a particularly uniform heating not only in the thickness direction of the film, but also in the longitudinal direction.

In principle, the desired pressing action mentioned can be achieved with the aid of a fixedly mounted and adjusted auxiliary device with respect to the heating roller. This is also the simplest embodiment of the means for applying a compressive force to the intermediate layer film. However, due to the greater flexibility and the ease of taking into account tolerances and wear phenomena, an adjustable positioning of the respective pressing means relative to the surface of the heating roller is preferred from the present point of view.

In special applications, the polymer film to be processed has a non-constant thickness in the width direction, wherein the thickness increases continuously in particular from one side edge to the other. In order to process the interlayer film thus obtained according to the present invention, a method control is proposed in which a peripheral gap having a non-constant width between the periphery of the heating roller and the periphery of the auxiliary heating roller or the surface of the roller shoe is adjusted according to a thickness profile of the interlayer film having a non-constant thickness over the width of the interlayer film.

In an apparatus designed for carrying out the method, an adjusting device is provided for adjusting such a guide gap with a non-constant width, for example for tilting an auxiliary heating roller or a heated roller shoe relative to the surface or axis of the heating roller. Such adjustment devices are known to the person skilled in the art and therefore do not require a more precise description here.

In the method according to the invention and the apparatus designed for carrying out the method, the plastic film is unwound from a supply roll and is conveyed directly to the heated roll, i.e. there is no further heated roll or roller between the supply roll and the heated roll. The heating roller is therefore not part of a heated pressure roller pair which is placed after the heating roller (heated cylinder), as is the case in the initially mentioned international patent application WO 2017/153167 a 1. The heated roller is thus the first roller or roller on which the plastic film unwound from the reserve roller is heated. This enables a simpler and cheaper control of the method, wherein in particular costs for the production of the installation can be saved.

Only (single) guide or deflection rollers are present between the heating roller and the drawing cone or drawing roller. Usually, the transport direction of the plastic film is changed on guide or deflection rollers. The guide or deflection rollers are always single rollers and are not arranged in pairs as a pressure roller pair in a coacting manner, i.e. in particular not for imparting a wedge shape to the plastic film, but only for guiding or deflecting the plastic film from the heating roller to the stretching cone or stretching roller. The adjacent guide or deflection rollers thus do not form a clear width through which the plastic film is transported in order to impart a specific shape, in particular a wedge shape, to the plastic film. Therefore, there is especially no pressure roller pair between the heating roller and the stretching cone or stretching roller.

Drawings

In an advantageous embodiment of the invention, the auxiliary heating roller is of conical or alternatively cylindrical design and is arranged obliquely to the axis of rotation of the heating roller and is pressed against the heating roller, so that the plastic film conveyed over the heating roller is provided with a wedge-shaped cross-sectional profile. The invention is explained in detail with the aid of the figures and examples. The figures are schematic and not to scale. The drawings are not intended to limit the invention in any way. Wherein:

figure 1 shows a schematic cross-sectional view of an apparatus according to a first embodiment of the invention;

fig. 2 shows a schematic cross-sectional view of an apparatus according to a second embodiment of the invention; and is

Fig. 3 shows a schematic cross-sectional view of an apparatus according to a third embodiment of the invention.

Detailed Description

Fig. 1 schematically shows a section of a plant 1 for processing and configuring a PVB film F arranged as an interlayer film in a composite glass sheet. As a component known per se, the installation 1 comprises a heating roll 2 and a drawing roll 3 shaped somewhat truncated-cone, which is also referred to as a drawing cone (umbrella). Furthermore, the installation comprises a plurality of transport, guide and deflection rollers, which are not represented individually here and whose function is known to the person skilled in the art or can be easily seen from the figures. It is to be understood that the pressing force of the PVB film F onto the peripheral area of the heated roller 2 surrounded by the PVB film is generated simultaneously by the turning and conveying rollers adjacent to the heated roller 2, and the pressing force onto the surface of the stretching cone is generated simultaneously by the rollers adjacent to the stretching cone 3.

In order to generate additional pressure on the PVB film in the surrounding area of the heated roller 2 and at the same time to supply additional thermal energy via the surface of the film facing away from the heated roller, five additional heated rollers 4 of significantly smaller diameter are arranged on the heated roller, which are referred to herein as auxiliary heated rollers. It is to be understood that the auxiliary heating roller 4 (and all other rollers) is held in the roller housing of the facility 1.

Preferably, the holding is performed by an adjusting means that enables a certain adjustment of the relative position of the auxiliary heating roller 4 with respect to the surface of the heating roller 2 and thus also the adjustment of the desired pressing force. It can also be provided that the heating elements integrated in the auxiliary heating roller 4 are adjustable in their heating power and/or that heating elements with different heating powers are inserted into different auxiliary heating rollers.

Fig. 2 shows a plant 1' in a different embodiment, in which the above-identified known components of the plant 1 from fig. 1 are also present and are denoted by the same reference numerals as there. However, instead of a plurality of auxiliary heating rollers, in the plant 1', a heated roller shoe 5 is arranged above the heating roller 2, which roller shoe has a circular-arc-shaped active surface 5a which is adapted to the partial region 2a of the surface of the heating roller 2 and forms a long semicircular circumferential gap with the heating roller, through which the PVB film F is conveyed. In this gap, the film is heated from both surfaces and is thus uniformly heated. It will be understood that the active surface 5a of the roller shoe 5 must have a significant sliding capacity with respect to the material of the film F passing through, in order to ensure a smooth passage of the film.

Fig. 2 also shows symbolically a pressing and adjusting device 6 assigned to the roller shoe 5, by means of which a desired pressing force and possibly also a non-constant gap width can be achieved, which the roller shoe applies to the film. The heatable properties of the roll shoe 5 can be achieved by a consecutive heating element or a plurality of heating elements (not shown). The provision of a plurality of heating elements can be advantageous because a different heat input can be achieved over the longitudinal extent of the active surface 5a than in a manner analogous to that described above for the auxiliary heating roller 4. Furthermore, both the individual heating elements and the plurality of heating elements can be designed to be adjustable with regard to their heating power.

Fig. 3 shows a plant 1 ″ as a further embodiment of the apparatus according to the invention, which in turn is equipped with a heating roll 2, a drawing cone 3 and a plurality of conveying, guiding and deflecting rolls on what can be regarded as known.

The facility 1 ″ differs from the facilities 1 and 1' in that a plurality of IR radiators 7 and individual pressing members 8 are provided in a partial region of the periphery of the heating roller 2. The pressing elements 8 are each arranged on the surface of the heating roller in the central region between the radiation application areas 7a of the radiators and are adjustable in their position relative to the surface of the heating roller, or in their pressing force. The heating powers of the IR radiators 7 can likewise be adjusted individually, or the heating powers of all IR radiators 7 can also be adjusted together. The number of IR radiators 7 and pressers 8 is here chosen only by way of example and it is not essential for the embodiment of the invention that the pressers are provided separately in all radiator spacing areas or completely.

The embodiments of the invention are not limited in general to the aspects highlighted above and to the examples described above, but can equally be implemented in a number of modifications within the scope of the appended claims.

List of reference numerals

1; 1'; 1 '' installation for treating and dispensing interlayer films (PVB films)

2 heating roller

2a surrounding surface of the heating roller 2

3 stretching rollers or cones

4 auxiliary heating roller

5 heated roller shoe

5a heated active surface of the roller shoe

6 adjusting and pressing device

7 IR radiator

7a radiation action zone

8 extrusion

F PVB film (interlayer film).

Claims

1. A method for manufacturing a thermoplastic interlayer film (F) for a composite glass sheet, said method comprising the steps of: heating the intermediate layer film by rotation of the heating roller (2) and subsequently stretching the intermediate layer film over a stretching cone or stretching roller (3) in order to guide the heated intermediate layer film through the stretching cone with a predetermined pressing force and thereby process and configure the heated intermediate layer film for installation into the composite glass sheet, wherein the intermediate layer film is not conveyed between the heating roller (2) and the stretching cone or stretching roller (3) to a pair of pressure rollers, wherein in the heating step on the heating roller, additionally thermal energy and/or a pressing force is applied to the surface of the intermediate layer film facing away from the heating roller.

2. A method according to claim 1, wherein the additional thermal energy and pressing force are applied by means of a plurality of auxiliary heated rollers (4) arranged on a partial area of the periphery of the heated roller (2).

3. The method of claim 1, wherein the additional thermal energy is applied as radiant heat by radiation with IR radiation.

4. A method according to claim 3, wherein the radiant heat is applied in a plurality of spaced apart radiation-active zones (7 a) and pressing of the interlayer film onto the periphery of the heating roller is performed between the radiation-active zones, respectively.

5. A method according to claim 1, wherein the additional thermal energy and the pressing force are applied by means of a heated roller shoe (5) arranged on a partial region of the periphery of the heated roller (2).

6. Method according to claim 2 or 5, wherein the auxiliary heated roller (4) or the heated roller shoe (5) is actively pressed against the intermediate layer film (F) moving over the periphery of the heated roller (2).

7. Method according to claim 2, 5 or 6, wherein the guiding gap with a non-constant width between the periphery of the heated roller (2) and the periphery of the auxiliary heated roller (4) or the surface of the roller shoe (5) is adjusted according to the thickness profile of the intermediate layer film (F) with a non-constant thickness over the width of the intermediate layer film.

8. Device (1; 1'; 1 ") for carrying out the method according to any one of the preceding claims, having:

a transport device for transporting the interlayer film (F) through the apparatus,

a heating roller (2) having an associated guide roller for guiding the intermediate layer film over a partial region of the periphery of the heating roller and heating the intermediate layer film there to a predetermined temperature, an

A drawing cone with associated guide rollers arranged downstream in the direction of transport of the intermediate layer film in order to guide the heated intermediate layer film with a predetermined pressing force via the drawing cone or drawing roller (3) and to process and configure the heated intermediate layer film for installation into the composite glass pane in this way, wherein no pressure roller pair is arranged between the heating roller (2) and the drawing cone or drawing roller (3), wherein means (4; 5; 7; 8) are associated with the heating roller for introducing additional thermal energy and/or pressing force onto the surface of the intermediate layer film facing away from the heating roller.

9. An apparatus as claimed in claim 8, wherein the means for introducing additional thermal energy and/or pressing force have a plurality of auxiliary heated rollers (4) arranged on a partial region of the periphery of the heated roller (2).

10. The apparatus according to claim 9, wherein the means for introducing additional thermal energy and/or pressing force comprises a plurality of IR radiators (7) arranged near a partial area of the periphery of the heated roller and facing the surface of the heated roller.

11. The apparatus according to claim 10, wherein the means for applying a pressing force has a plurality of pressing rollers or pressing members (8) placed on the periphery of the heated roller (2) between the radiation action zones (7 a) defined by the plurality of IR radiators (7).

12. Apparatus according to claim 11, wherein the means for introducing additional thermal energy and/or compressive force comprise a heated roller shoe (5) arranged in a partial region of the periphery of the heated roller (2), said roller shoe forming with the peripheral region (2 a) of the heated roller a guide gap which is coordinated with the thickness of the interlayer film.

13. An apparatus as claimed in claim 9, 11 or 12, wherein means (6) for actively pressing the auxiliary heating roll (4) or the pressure roll or the pressure body (8) or the heated roll shoe (5) are assigned to the heating roll.

14. An apparatus as claimed in claim 10, 11 or 12, wherein the auxiliary heating roll (4) or the press roll or the press ram (8) or the heated roll shoe (5) is assigned a regulating device (6) for regulating the width of the guide gap which is not constant over the length of the heating roll, for processing an intermediate layer film having a thickness which is not constant over the width of the intermediate layer film.