CA1127948A - Method of manufacturing automobile windshield - Google Patents
Method of manufacturing automobile windshieldInfo
- Publication number
- CA1127948A CA1127948A CA287,289A CA287289A CA1127948A CA 1127948 A CA1127948 A CA 1127948A CA 287289 A CA287289 A CA 287289A CA 1127948 A CA1127948 A CA 1127948A
- Authority
- CA
- Canada
- Prior art keywords
- interlayer film
- film
- heating
- elongating
- cone shape
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Joining Of Glass To Other Materials (AREA)
Abstract
An automobile windshield is manufactured by laminating a pair of curved glass sheets with an interlayer film. The interlayer film is manufactured by heating a ribbon interlayer film to an elongatable temperature while continuously transferring the film and winding the interlayer film up on a cone shape drum while elongating the film with a varying elongating distribution in the transverse direction so as to curve the interlayer film in longitudinal direction. The tinted part is formed at upper end in parallel to the edge of the windshield by elongating the ribbon interlayer film with varying elongating distribution in the transverse direction.
Description
llZ7948 The present invention relates to a method of manufactur-ing an automobile windshield having a curved tinted part parallel to the upper edge thereof.
The present invention will be described with reference to the accompanying drawings in which, Figure 1 is a front view of an automatic windshield having a tinted part at upper part;
~ Figure 2 is a plan view of a ribbon interlayer film which is not elongated;
Figure 3 is a front view of a curved laminated glass manufactured using a ribbon interlayer film which is not elongated;
Figures 4 and 5 respectively show the conventional elongating methods;
Figure 6 is a front view of a curved ribbon interlayer film, which is elongated and cut;
Figure 7 is a schematic view of a heat elongating apparatus used'in the method of the present invention; and Figure 8 is a partially enlarged schematic view of the apparatus.
Automobile windshields having a tinted part in the upper end (as shown in Figure 1) have been used for improving sighting condition for drivers. The tinted part can be obtained by coloring the interlayer film. The automobile windshields can be manufactured by laminating a pair of glass sheets with the interlayer film having the tinted part. However, the upper edge of the automobile windshield is curved contiguous with the shape of the body of the automobile. Accordingly, it is preferable to form the tinted part parallel to the upper edge of the curved glass sheets for appearance and function. However, when a ribbon interlayer film for the laminated glass (Figure 2) is cut to form the interlayer film having the tinted part (1) as shown in Figure 1 and the interlayer film is held between a pair of curved glass ~lZ7948 sheets to form the laminated glass, the width of the tinted ~ part becomes different in transverse direction of the windshield and narrow at the central part (Figure 3) whereby the upper edge of the laminated glass is not parallel to the lower edge of the tinted part of the interlayer film. When the windshield glass shown in Figure 1 is manufactured by using the interlayer film, it is necessary to elongate the tinted part by heating it so as to be parallel tc the upper edge of the windshield glass.
Heretofore, in one method of elongating the interlayer film the ribbon interlayer film is cut to the size of the wind-shield glass and the interlayer film is elongated in the arrow line direction shown in Figure 4 so as to be parallel in the tinted part to the curved upper edge of the windshield glass (U.S. Patent No. 2,817,717). In another method the ribbon interlayer film is wound on a roll and heated and the roll is expanded in a cone shape so as to elongate the interlayer film (Figure 5) (U.S. Patent No. 2,937,407). In yet another method the ribbon interlayer film is heated to elongatable temperature during continuous travel, and the film continuously elongated by passing the film between a pair of cone shape rolls and the film is then cut in a desired shape (U.S. Patent No. 3,912,440).
The first method has however the disadvantages of inferior productivity and requirement of remarkable high skill because the interlayer film is cut in the predetermined size and it is individually elongated. The second method has the disadvantages of non-uniform degree of elongation because the interlayer film is wound on the roll and then the roll is expanded in the cone shape. The third method has the disadvantage that the release of the strain caused in the interlayer film after elongating it, is not sufficient even though the interlayer can be continuously elongated and the productivity is high.
The present invention provides a method of manufacturing an automobile windshield by laminating a pair of curved glass ~27948 sheets with an interlayer film which is elongated in curved shape.
The present invention also provides a method of manufacturing an automobile windshield by laminating a pair of curved glass sheets with a curved interlayer film having a tinted part parallel to the upper edge of the windshield.
The present invention also provides a method of elongating an interlayer film in which the interlayer film can be continuously elongated and the strain releasing treatment after elongating the interlayer film is easily attained.
The present invention still further provides a method of elongating an interlayer film in which the operations for varying curvature for elongating the interlayer film is - simple and the productivity can be easily controlled.
According to the present invention the method of manufacturing an automobile windshield comprises laminating a pair of curved glass sheets with an interlayer film which is formed by heating a ribbon interlayer film to the elongatable temperature while continuously transferring the film and winding the interlayer film up on a cone shape drum with varying elongation distribution in transverse direction so as to curve the interlayer film in longitudinal direction andthen desirably releasing the strain on the film in an oven.
Referring once more to the accompanying drawings, Figure 7 is a schematic view of the typical elongating apparatus used in the method of the present invention. The ribbon interlayer film (2) to be elongated isset on a film set table (5) as a film roll (6) and is guided by guide rolls (9) to the heating rolls (7) and (8) on which the film is continuously heated to the elongatable temperature and is then wound up on a cone shape drum (11) having the required taper for the film on take up table (4) after elongating the film with different degree of elongation ~Z7948 in transverse direction with the condition being held by the pinch rollS (10) and (10').
The heating rolls (7) and (8) are heated to the desired temperature by passing the heat medium, such as steam from the heater (3), into the heating rolls whereby the interlayer film
The present invention will be described with reference to the accompanying drawings in which, Figure 1 is a front view of an automatic windshield having a tinted part at upper part;
~ Figure 2 is a plan view of a ribbon interlayer film which is not elongated;
Figure 3 is a front view of a curved laminated glass manufactured using a ribbon interlayer film which is not elongated;
Figures 4 and 5 respectively show the conventional elongating methods;
Figure 6 is a front view of a curved ribbon interlayer film, which is elongated and cut;
Figure 7 is a schematic view of a heat elongating apparatus used'in the method of the present invention; and Figure 8 is a partially enlarged schematic view of the apparatus.
Automobile windshields having a tinted part in the upper end (as shown in Figure 1) have been used for improving sighting condition for drivers. The tinted part can be obtained by coloring the interlayer film. The automobile windshields can be manufactured by laminating a pair of glass sheets with the interlayer film having the tinted part. However, the upper edge of the automobile windshield is curved contiguous with the shape of the body of the automobile. Accordingly, it is preferable to form the tinted part parallel to the upper edge of the curved glass sheets for appearance and function. However, when a ribbon interlayer film for the laminated glass (Figure 2) is cut to form the interlayer film having the tinted part (1) as shown in Figure 1 and the interlayer film is held between a pair of curved glass ~lZ7948 sheets to form the laminated glass, the width of the tinted ~ part becomes different in transverse direction of the windshield and narrow at the central part (Figure 3) whereby the upper edge of the laminated glass is not parallel to the lower edge of the tinted part of the interlayer film. When the windshield glass shown in Figure 1 is manufactured by using the interlayer film, it is necessary to elongate the tinted part by heating it so as to be parallel tc the upper edge of the windshield glass.
Heretofore, in one method of elongating the interlayer film the ribbon interlayer film is cut to the size of the wind-shield glass and the interlayer film is elongated in the arrow line direction shown in Figure 4 so as to be parallel in the tinted part to the curved upper edge of the windshield glass (U.S. Patent No. 2,817,717). In another method the ribbon interlayer film is wound on a roll and heated and the roll is expanded in a cone shape so as to elongate the interlayer film (Figure 5) (U.S. Patent No. 2,937,407). In yet another method the ribbon interlayer film is heated to elongatable temperature during continuous travel, and the film continuously elongated by passing the film between a pair of cone shape rolls and the film is then cut in a desired shape (U.S. Patent No. 3,912,440).
The first method has however the disadvantages of inferior productivity and requirement of remarkable high skill because the interlayer film is cut in the predetermined size and it is individually elongated. The second method has the disadvantages of non-uniform degree of elongation because the interlayer film is wound on the roll and then the roll is expanded in the cone shape. The third method has the disadvantage that the release of the strain caused in the interlayer film after elongating it, is not sufficient even though the interlayer can be continuously elongated and the productivity is high.
The present invention provides a method of manufacturing an automobile windshield by laminating a pair of curved glass ~27948 sheets with an interlayer film which is elongated in curved shape.
The present invention also provides a method of manufacturing an automobile windshield by laminating a pair of curved glass sheets with a curved interlayer film having a tinted part parallel to the upper edge of the windshield.
The present invention also provides a method of elongating an interlayer film in which the interlayer film can be continuously elongated and the strain releasing treatment after elongating the interlayer film is easily attained.
The present invention still further provides a method of elongating an interlayer film in which the operations for varying curvature for elongating the interlayer film is - simple and the productivity can be easily controlled.
According to the present invention the method of manufacturing an automobile windshield comprises laminating a pair of curved glass sheets with an interlayer film which is formed by heating a ribbon interlayer film to the elongatable temperature while continuously transferring the film and winding the interlayer film up on a cone shape drum with varying elongation distribution in transverse direction so as to curve the interlayer film in longitudinal direction andthen desirably releasing the strain on the film in an oven.
Referring once more to the accompanying drawings, Figure 7 is a schematic view of the typical elongating apparatus used in the method of the present invention. The ribbon interlayer film (2) to be elongated isset on a film set table (5) as a film roll (6) and is guided by guide rolls (9) to the heating rolls (7) and (8) on which the film is continuously heated to the elongatable temperature and is then wound up on a cone shape drum (11) having the required taper for the film on take up table (4) after elongating the film with different degree of elongation ~Z7948 in transverse direction with the condition being held by the pinch rollS (10) and (10').
The heating rolls (7) and (8) are heated to the desired temperature by passing the heat medium, such as steam from the heater (3), into the heating rolls whereby the interlayer film
(2) which is continuously fed from the film roll (6) is heated during passage of the film therethrough. A suitable number of the heating rolls can be disposed along the passage of the interlayer film (2). Usually, a plurality of the heating rolls àre disposed at different levels so as to rapidly heat the interlayer film (2) to the elongatable temperature. In the embodi-ment shown in Figure 7 a combination of two heating rolls (7) and (8) are used and they are driven at a constant speed by interlocking the worm gear of the driving shaft with the gears on the shafts of the heating rolls. In order to prolong the contact time of the interlayer film (2) with the heating rolls (7) and (8) so as to increase the heating efficiency, it is preferable to use heating rolls (7) and (8) having a relatively large diameter. In order to prevent the tacky adhesion of the interlayer film (2) on the surface of the heating rolls (7) and (8) to maintain surface properties during the heating operation, the surface of the heating rolls (7) and (8) should if necessary be treated by the surface processing. It is indispensable to use the heating roll treated by the surface processing for heating the clean interlayer film having no antitackifying agent on the surface. When a plurality of the heating rolls are used, the heating roll in the high temperature zone should be treated by the surface processing.
In the embodiment as shown in Figure 8, only the heating roll (8) in high temperature zone is treated by the surface processing. Thus, the surface of the heating roll (8) contacted with the interlayer film (2) is treated by rough surface processing -` ~.lZ7948 so as to prevent the tacky adhesion. The surface is usually maintained in clean condition by chromium plating. For this purpose it is also possible to coat the surface of the heating roll with a heat resistant and non-tacky resin such as fluorinated resin.
The cone shape drum (11) is disposed downstream of the heating roll (8) and the heated interlayer film (2) is wound up wit;h elongation of the film with the different elongation distri-bution in the transverse direction between the pinch rolls (10) and (10'). Thus the interlayer film (2) is elongated between the pinch rolls (10) and (10') and the cone shape drum (11) which members are rotated in the arrow line directions. The diameter of the cone shape drum for winding up the interlayer film (2) is continuously axially varied. The cone shape drum has a cone shape surface for winding the film. Accordingly, when the heated ribbon interlayer film (2) is wound up thereon, the winding speed depends upon the tension and the diameter of the cone shape drum.
The interlayer film wound on the cone shape drum (11) having a larger diameter is elongated to a higher degree corresponding to the difference of the winding speed relative to the interlayer film wound up on a cone shape drum having a smaller diameter. The interlayer film (2) is wound up under elongation with the elongation distribution proportional to the diameter of the cone shape drum (11) in transverse direction. For example, when the tinted part (1) of the ribbon interlayer film (2) is curved as shown in Figure 6, the tinted part (1) of the interlayer film (2) is disposed so as to wind up on the cone shape drum (11) on the side of smaller diameter, whereby the other part is elongated to a higher degree as the interlayer film is wound up on the cone shape drum (11).
The revolution of the cone shape drum (11) can be controlled depending upon variation of the diameter of the cone l~Z7g48 shape drum to give a constant peripheral speed for winding up the interlayer film (2). The diameter of the cone shape drum (11) is preferably more than 300 mm in practice so as to readily attain the elongation.
The interlayer (2) can be automatically elongated with the predetermined distribution in transverse direction by the winding up on the cone shape drum (11~. The degree of curvature of the tinted part (1) of the interlayer film (2) in longitudinal direction can be varied by controlling the tension applied to the interlayer film (2) in the operation for example, by varying the angle of the taper of the cone shape drum, changing the diameter of the cone shape drum in the axial direction of the cone shape drum and varying the angle of the cone shape drum in the apparatus.
The variation of elongation of the interlayer film (2) is increased in transverse direction depending upon increasing the difference of the diameter of the cone shape drum in the axial direction of the cone shape drum, whereby the degree of curvature of the tinted part (1) of the interlayer film (2) is increased. In the present invention, the arrangement of the axis of the pinch roll (10) and the axis of the cone shape drum is selected depending upon the curvature for elongating the interlayer film. Referring to Figure 7, the interlayer film elongated by winding up on the cone shape drum is heat treated in the oven (12) whereby the strains caused by the elongation of the interlayer film is released. For example, it is kept in the oven at 60 to 90C for 20 minutes to 3 hours.
The interlayer film treated by the method of the present invention has the characteristics as the interlayer film for the laminated glass sheets and it is the ribbon thermoplastic film. For example, a polyvinylbutyral film is especially prefer-able though a polyurethane film, an ethylene-vinylacetate film and other interlayer films can be used.
~Z7948 In the present invention, the interlayer film is heated to the elongatable temperature, that is, the temperature for imparting thermoplastic property but preventing tacky adhesion by softening it before elongating the interlayer film. The optimum temperature is selected depending upon kinds of the resin for the interlayer film. For example, when the polyvinylbutyral film having a thickness of 15 mil to 30 mil is used, it is heated at about 40C to 90C preferably 40C to 60C. The heating method is no~ confined to the contact heating method using the heating - roll and can be also a heating method using an electric heater, a heating method using a hot air, a radiation heating method and other heating methods which do not adversely affect to the interlayer film.
The embodiment for elongating the interlayer film having the tinted part has been illustrated, however, the method of the present invention can be also applied for the interlayer film haviny non-tinted part.
In accordance with the present invention, the ribbon interlayer film isheated during passage to the elongatable temperature and then, the heated interlayer film is elongated by winding up on the cone shape drum with the applicationof tension having a different distribution, whereby the elongating can be continuously and uniformly attained. Moreover, the elongated interlayer film is wound up on the cone shape drum whereby it can be maintained for the predetermined time and the strain caused in the interlayer film can be substantially released.
The method of the present invention can be carried out by the batch operation by winding up on the cone shape drum whereby the method can be applied for small production and the productivity can be easily controlled. Moreover, the curvature formed by elongating can be varied only by changing the cone shape drum whereby the production of various kinds of the elongated ~7948 interlayer films can be easily attained. The interlayer film is elongated to form the desired curved shape whereby the percentage of inferior curved film can be decreased.
In the embodiment as shown in Figure 8, only the heating roll (8) in high temperature zone is treated by the surface processing. Thus, the surface of the heating roll (8) contacted with the interlayer film (2) is treated by rough surface processing -` ~.lZ7948 so as to prevent the tacky adhesion. The surface is usually maintained in clean condition by chromium plating. For this purpose it is also possible to coat the surface of the heating roll with a heat resistant and non-tacky resin such as fluorinated resin.
The cone shape drum (11) is disposed downstream of the heating roll (8) and the heated interlayer film (2) is wound up wit;h elongation of the film with the different elongation distri-bution in the transverse direction between the pinch rolls (10) and (10'). Thus the interlayer film (2) is elongated between the pinch rolls (10) and (10') and the cone shape drum (11) which members are rotated in the arrow line directions. The diameter of the cone shape drum for winding up the interlayer film (2) is continuously axially varied. The cone shape drum has a cone shape surface for winding the film. Accordingly, when the heated ribbon interlayer film (2) is wound up thereon, the winding speed depends upon the tension and the diameter of the cone shape drum.
The interlayer film wound on the cone shape drum (11) having a larger diameter is elongated to a higher degree corresponding to the difference of the winding speed relative to the interlayer film wound up on a cone shape drum having a smaller diameter. The interlayer film (2) is wound up under elongation with the elongation distribution proportional to the diameter of the cone shape drum (11) in transverse direction. For example, when the tinted part (1) of the ribbon interlayer film (2) is curved as shown in Figure 6, the tinted part (1) of the interlayer film (2) is disposed so as to wind up on the cone shape drum (11) on the side of smaller diameter, whereby the other part is elongated to a higher degree as the interlayer film is wound up on the cone shape drum (11).
The revolution of the cone shape drum (11) can be controlled depending upon variation of the diameter of the cone l~Z7g48 shape drum to give a constant peripheral speed for winding up the interlayer film (2). The diameter of the cone shape drum (11) is preferably more than 300 mm in practice so as to readily attain the elongation.
The interlayer (2) can be automatically elongated with the predetermined distribution in transverse direction by the winding up on the cone shape drum (11~. The degree of curvature of the tinted part (1) of the interlayer film (2) in longitudinal direction can be varied by controlling the tension applied to the interlayer film (2) in the operation for example, by varying the angle of the taper of the cone shape drum, changing the diameter of the cone shape drum in the axial direction of the cone shape drum and varying the angle of the cone shape drum in the apparatus.
The variation of elongation of the interlayer film (2) is increased in transverse direction depending upon increasing the difference of the diameter of the cone shape drum in the axial direction of the cone shape drum, whereby the degree of curvature of the tinted part (1) of the interlayer film (2) is increased. In the present invention, the arrangement of the axis of the pinch roll (10) and the axis of the cone shape drum is selected depending upon the curvature for elongating the interlayer film. Referring to Figure 7, the interlayer film elongated by winding up on the cone shape drum is heat treated in the oven (12) whereby the strains caused by the elongation of the interlayer film is released. For example, it is kept in the oven at 60 to 90C for 20 minutes to 3 hours.
The interlayer film treated by the method of the present invention has the characteristics as the interlayer film for the laminated glass sheets and it is the ribbon thermoplastic film. For example, a polyvinylbutyral film is especially prefer-able though a polyurethane film, an ethylene-vinylacetate film and other interlayer films can be used.
~Z7948 In the present invention, the interlayer film is heated to the elongatable temperature, that is, the temperature for imparting thermoplastic property but preventing tacky adhesion by softening it before elongating the interlayer film. The optimum temperature is selected depending upon kinds of the resin for the interlayer film. For example, when the polyvinylbutyral film having a thickness of 15 mil to 30 mil is used, it is heated at about 40C to 90C preferably 40C to 60C. The heating method is no~ confined to the contact heating method using the heating - roll and can be also a heating method using an electric heater, a heating method using a hot air, a radiation heating method and other heating methods which do not adversely affect to the interlayer film.
The embodiment for elongating the interlayer film having the tinted part has been illustrated, however, the method of the present invention can be also applied for the interlayer film haviny non-tinted part.
In accordance with the present invention, the ribbon interlayer film isheated during passage to the elongatable temperature and then, the heated interlayer film is elongated by winding up on the cone shape drum with the applicationof tension having a different distribution, whereby the elongating can be continuously and uniformly attained. Moreover, the elongated interlayer film is wound up on the cone shape drum whereby it can be maintained for the predetermined time and the strain caused in the interlayer film can be substantially released.
The method of the present invention can be carried out by the batch operation by winding up on the cone shape drum whereby the method can be applied for small production and the productivity can be easily controlled. Moreover, the curvature formed by elongating can be varied only by changing the cone shape drum whereby the production of various kinds of the elongated ~7948 interlayer films can be easily attained. The interlayer film is elongated to form the desired curved shape whereby the percentage of inferior curved film can be decreased.
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of manufacturing an automobile wind-shield which comprises laminating a pair of curved glass sheets with an interlayer of polyvinylbutyral film having a tinted strip in the longitudinal direction, comprising: a) continuously passing said polyvinylbutyral film to a heating zone and heating said polyvinylbutyral to 40 to 60°C; b) elongating said poly-vinylbutyral film in the longitudinal direction by an amount which varies in the transverse direction to curve said poly-vinylbutyral film by continuously winding said heated polyvinyl-butyral film on a conical drum; and c) heating said curved polyvinylbutyral film at from 60 to 90°C to release the strain induced by said elongation.
2. The method of claim 1 wherein the polyvinylbutyral.
interlayer film is wound upon said conical drum through pinch rolls.
interlayer film is wound upon said conical drum through pinch rolls.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA287,289A CA1127948A (en) | 1977-09-22 | 1977-09-22 | Method of manufacturing automobile windshield |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA287,289A CA1127948A (en) | 1977-09-22 | 1977-09-22 | Method of manufacturing automobile windshield |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1127948A true CA1127948A (en) | 1982-07-20 |
Family
ID=4109600
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA287,289A Expired CA1127948A (en) | 1977-09-22 | 1977-09-22 | Method of manufacturing automobile windshield |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1127948A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4554199A (en) * | 1981-03-06 | 1985-11-19 | Saint-Gobain Vitrage | Inner lamina, and process for manufacture, for vehicle windshield |
-
1977
- 1977-09-22 CA CA287,289A patent/CA1127948A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4554199A (en) * | 1981-03-06 | 1985-11-19 | Saint-Gobain Vitrage | Inner lamina, and process for manufacture, for vehicle windshield |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |