JPH10119184A - Transparent laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent warpage of a laminate, to enhance adhesive strength and impact resistant strength and to prevent emulsification of a PC plate by laminating a polyvinyl butyral(PVB) film, a resin layer having higher viscosity than the PVB film, and an intermediate film at the ambient temperature. SOLUTION: The transparent laminate 10 is formed by laminating an intermediate film 51, hot-melt urethane adhesive layer 41 and a PC plate 2 via a resin layer having higher viscosity than that of a PVB film on the PVB film of one or two glass plates at the ambient temperature. The film 51 is constituted to sandwich a resin layer 53 having higher viscosity than that of the PVB film at the ambient temperature between PVB films 52 of both sides. The layer 53 has flexibility at the ambient temperature, and absorbs a difference of expansion coefficients generated at the laminate of the glass plate and PC plate having different linear expansion coefficients at the time of heating. And, the layer 41 shuts off migration of plasticizer and additive contained in the film 52 to the plate 2 to prevent emulsification of the PC plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent laminate used for windows of automobiles, railway vehicles, ships, buildings and the like.

[0002]

2. Description of the Related Art It is common to use glass sheets as windows for vehicles, ships, and buildings. These windows are used to improve impact resistance and prevent penetration of collision objects.
Safety laminated glass in which a film made of polyvinyl butyral (PVB) or the like is sandwiched between two glass plates is generally used.

[0003] However, such a laminated glass is so heavy that it is difficult to penetrate it upon impact, but cracks may occur on the glass plate. In view of this, a glass / PC combined structure that uses a polycarbonate (PC) plate as a material that is difficult to crack and that reduces breakage has been proposed.

As a method for easily obtaining a laminated body of a glass plate and a PC plate, there is a laminating method using a heated adhesive sheet such as a PVB film, an ethylene-vinyl acetate copolymer (EVA) film, or a urethane film. In particular, EVA films and urethane films do not contain a plasticizer and have good water resistance.
Suitable for bonding to boards.

On the other hand, PVB generally has an additive or a plasticizer mixed in the film in order to obtain flexibility and penetration resistance, so that it is difficult to obtain good adhesion to a PC board. is there. In addition, since the PC board is whitened within a short period of time after bonding and the transparency of the laminated board is reduced, it has been difficult to select a material used in a long-term use environment.

[0006]

However, the above EV
The A film and the urethane-based film are of a heat fusion type and generally require heating at 80 ° C. or higher. For this reason, the difference in the linear thermal expansion coefficient between the glass plate and the PC plate causes a warp of 0.7% or more when the component after the heat compression bonding returns to room temperature.

[0007] Regarding the adhesion between a glass plate and a PC plate, a laminate having the structure of glass plate / PVB / hot melt type urethane film / PC plate (Japanese Patent Laid-Open No. 8-15618).
7) has been proposed. According to this configuration, the PC board and the P
Since it does not come into contact with VB, white turbidity of the PC board can be prevented, but the problem of warpage of the laminate has not been solved. An object of the present invention is to provide a novel transparent laminate of a glass plate and a PC plate that solves the above-mentioned problems of the prior art.

[0008]

The present invention provides a transparent laminate comprising a glass plate / intermediate film / hot melt type urethane adhesive layer / polycarbonate plate laminated in this order,
A transparent laminate is provided, wherein the intermediate film is a laminate of a polyvinyl butyral film / a resin layer / polyvinyl butyral film having a higher viscosity at room temperature than a polyvinyl butyral film in this order.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic sectional view of an essential part showing an example of the transparent laminate of the present invention. This transparent laminate 10
A layer (intermediate film) 51/1/2 of a glass plate laminated with a resin layer having a higher viscosity at room temperature than a PVB film at a room temperature / a hot melt type urethane-based adhesive layer 41 / PC
The plates 2 are laminated in this order. These layers are firmly joined and integrated with each other through a thermocompression bonding step.

The intermediate film 51 has three layers as shown in FIG. That is, the intermediate film 51 has a configuration in which the PVB film 52 sandwiches the resin layer 53 having a higher viscosity at room temperature than the PVB film from both sides.

The resin layer 53 having higher viscosity at room temperature than the PVB film has flexibility at room temperature. An index of this flexibility is a glass transition temperature (T _g ). The lower the T _g below room temperature, the higher the viscosity of the resin. Then, a resin layer having a higher viscosity than the PVB film is sandwiched between the two PVB films at room temperature conditions, and is interposed between the glass plate and the PC plate. Can absorb the difference in the coefficient of expansion that occurs when the laminate is heated.

As the resin layer having a higher viscosity than the PVB film at room temperature, an acetal resin layer can be preferably exemplified in view of the bonding property with the PVB film. Specifically, it is preferable to use one having a T _g of −20 to + 10 ° C.
Since the T _g of normal PVB film is about -20~ + 40 ℃,
By interposing a layer having a lower T _g between the PVB films, a layer that is more flexible than the PVB film at around room temperature can be provided between the PVB films.

By providing a layer more flexible than the PVB film near the room temperature between the PVB films, the coincidence effect can be reduced. The intermediate film having the above-described configuration is also an intermediate film that can eliminate a decrease in sound insulation performance due to a coincidence effect. As described above, since the PVB film has low viscosity at room temperature, the effect of absorbing warpage at room temperature is small even if the thickness is simply increased.
On the other hand, the acetal-based resin layer has a high viscosity and a viscous property, and absorption of warpage can be ensured by further increasing the thickness.

The adhesion between the PVB film and the glass plate is sufficiently large as demonstrated with conventional laminated glass, and the peel strength of the glass plate 1 can be increased. The hot-melt urethane-based adhesive layer 41 adheres to the PC board 2 by using a type in which an adhesive component is internally added to the film, and has a large adhesive strength. Furthermore, since the PVB film and the hot-melt urethane-based adhesive layer 41 are firmly bonded, the laminate 10 is firmly integrated as a whole.

Further, the intermediate film 51 is bonded to the glass plate 1,
Since the hot-melt urethane-based adhesive layer 41 is bonded to the PC board 2, the interlayer 51 and the PC board 2 are isolated from each other by the hot-melt urethane-based adhesive layer 41. The hot-melt urethane-based adhesive layer 41 is heated and melted at the time of thermocompression bonding to fuse with the intermediate film 51, and the PVB
It blocks plasticizers and additives contained in the film from migrating to the PC board, thereby preventing the PC board from whitening and devitrifying.

Since the urethane-based adhesive layer itself is a transparent non-yellowing type and has no adverse effects such as devitrification even when it comes into contact with a PC board, the laminate as a whole can maintain good transparency over a long period of time. Since the PC board 2 has a high impact strength, the PC board 2 compensates for the low impact strength of the glass plate and imparts impact resistance to the laminate.

The intermediate layer 3 composed of the intermediate film 51 and the hot-melt urethane-based adhesive layer 41 serves to reduce the impact caused by the collision of a flying object with the laminate 10 together with the PC board. In addition, in applications such as windshields for vehicles, it is different in order to prevent flying objects from penetrating into the laminate and preventing occupants from being released outside the vehicle, and to prevent fragments from being scattered even if the glass plate or PC plate is damaged by collision. In order to prevent warpage due to the difference in expansion coefficient that occurs when the plate material having a thermal expansion coefficient is thermally compressed,
The total thickness is preferably as large as 0.7 to 2.0 mm.

Of the total thickness, the thickness of the hot-melt urethane-based adhesive layer 41 is preferably 0.1 to 0.8 mm. By setting the thickness of the hot-melt type urethane-based adhesive layer 41 to 0.1 mm or more, the plasticizer of the PVB film and the additives are prevented from migrating to the PC resin plate over the entire surface of the laminate, and to 0.3 mm or more. By
The ability of plasticizers and additives to inhibit migration can be increased. Since the urethane-based adhesive layer is expensive and the purpose of using the adhesive layer is to obtain the above-mentioned blocking effect of the plasticizer and the additive, the thickness is more preferably 0.6 mm or less.

The thickness of the intermediate film 51 is preferably from 0.2 to 1.3 mm. Among them, the thickness of the flexible resin layer such as the acetal resin layer (the resin layer 53 having higher viscosity than the PVB film at room temperature) is preferably 0.1 to 1.0 mm. This is because, by increasing the thickness as described above, the absorption of the warp can be ensured.

The hot melt type urethane adhesive layer 41 is
It is preferable to use a hot-melt polyurethane resin adhesive formed into a film-like solid from the viewpoint of easy handling. For example, it is a material which is softened and bonded at a temperature of 80 to 150 ° C., and “Crystal Flex PE-399” (Morton, USA) (softening temperature of 100 ° C. or less) can be preferably used. The intermediate film 51 is softened at a heating temperature of 80 to 150 ° C. and adheres to the glass. For example, an “acetal-based sound insulating intermediate film” manufactured by Sekisui Chemical Co., Ltd. can be preferably used.

The glass sheet used for the transparent laminate of the present invention may be appropriately selected depending on the use of the laminate, such as a sheet glass for automobiles, a normal single sheet glass for construction, a laminated glass, a tempered glass having a surface strengthening treatment, and the like. sell. The PC board may be subjected to a weather resistance treatment or a surface hardening treatment.

The thicknesses of the glass plate and the PC plate are appropriately determined depending on the use of the laminate and the required performance.
It is preferable that the thickness of the PC board be about 1 to 5 mm with respect to about mm.

FIGS. 3 (a) and 3 (b) are schematic cross-sectional views of a main part of the transparent laminate of the present invention, showing a preferred embodiment of an end portion. As shown in FIG. 1, the transparent laminate 10 has a glass plate 1 / intermediate film 51 / hot melt type urethane-based adhesive layer 4
1 / PC board 2 is laminated in this order. The end face of the intermediate film 51 is covered with the urethane-based adhesive layer 41. Thereby, penetration of moisture into the PVB film can be prevented by covering the end surface with the urethane-based adhesive layer, and the water resistance of the laminate can be improved.

In this case, the outer size of the glass plate 1 is made larger than the outer size of the PC plate 3 so that the outer periphery of the glass plate 1 is
By protruding from the outer periphery of the C plate 3, the glass plate 1 can be used as a mounting portion of the vehicle, and a flash surface of the vehicle can be realized. The external dimensions can be appropriately selected and determined according to the application of the laminate of the present invention and the like.

In the bonding step of the laminate, a glass plate, an intermediate film, a hot-melt type urethane-based adhesive film and PC
The plates are laminated in this order, and the glass plate and the PC plate are uniformly pressed and laminated by heating in a vacuum bag or a reduced pressure heating method. At the heating temperature of 80 to 150 ° C., the PVB film softens and adheres to the glass, the hot-melt polyurethane adhesive film becomes a softened state and fills and joins between the interlayer and the PC board, and after cooling, hot-melt urethane-based adhesive When the film solidifies, it becomes an intermediate layer integral with the intermediate film.

When the end face of the intermediate film is covered as shown in FIG. 3, as shown in FIG. 4, a hot melt type urethane adhesive film for the end face separate from the hot melt type urethane adhesive film is used. The hot-melt type urethane-based adhesive film is integrated with the end face of the intermediate film and is interposed between the intermediate film and the PC board while covering the end face of the intermediate film by heat-pressing.

In the above case, since the hot-melt type urethane-based adhesive film is in a softened state at a heating temperature of 80 to 150 ° C. at the time of bonding, the molding pressure can be reduced and the intermediate film and P
The hot melt polyurethane adhesive can be prevented from flowing out of the gap between the C plate and the intermediate layer, the thickness of the intermediate layer can be made uniform, and the intermediate film and the PC plate can be sufficiently filled and joined.

If the bonding temperature is too high, there is a difference of 100 ° C. or more from the room temperature which is usually used. Therefore, the difference in the linear thermal expansion coefficient between the glass plate and the PC plate cannot be reduced, and the difference in the expansion and contraction of the glass plate The phenomenon that the four sides are pulled (warped) toward the PC plate side becomes remarkable, and the glass plate may be broken when the glass plate and the PC plate are returned to room temperature after pressure bonding. Therefore, it is desirable to perform pressure bonding at a temperature as low as possible at 80 to 120 ° C. Further, the PC board is 0.2 to 0.2.
Since it absorbs 5% of moisture and gradually generates water vapor in an atmosphere of 100 ° C. or higher, it is preferable that the temperature is on the low temperature side where the urethane-based adhesive film can be melted.

As a method for producing the laminate, a conventional adhesive molding method such as a press method or a roll method can be used. In the case of the method for producing a laminate of the present invention, as described above, a glass bag is placed in a vacuum-packed bag. A method in which a plate, an intermediate film, a urethane-based adhesive film, and a PC plate are put and vacuum-compression-bonded is simple and preferable. In this vacuum pack bag, for example, as a sealing portion having heat sealing property, adhesiveness or adhesiveness in an opening portion, the above-mentioned respective plates and films are sealed, and then the sealing portion is sealed and pressure-bonded. This example
It is also disclosed in JP-B-63-1278.

[0030]

【Example】

(Lamination Example A) Width 60 cm x height 30 cm x thickness 4.0 mm
Glass plate 1, width 58cm × length 30cm × thickness 3.0m
m, a PC board 2 having a PVB film / acetal resin layer / PVB film composed of a 0.4 mm thick “acetal-based sound insulating butyral film” manufactured by Sekisui Chemical Co., Ltd.
4mm Morton “Crystal Flex PE-3”
Using the hot-melt urethane-based adhesive layer 41 made of “99”, a laminate A having a cross-section and an end face configuration shown in FIG. 3A was formed.

The laminated body A was packed in a vacuum bag after evacuation in a vacuum laminating machine and heated at 95 ° C., 110 ° C., 125 ° C., and a molding pressure of 5 kg.
The adhesive film was obtained by melting and softening the adhesive film under the conditions of / cm ² and a holding time of 1 hour. In the laminated body A after the molding, no whitening was observed on the PC board, the transparency was high, and the PC board had good flatness without deformation or edge flow.

(Lamination Example B) The intermediate film 51 having the three-layer structure described above.
Were laminated in the same manner as in Lamination Example A except that the total thickness of the film was 0.8 mm, to obtain a laminate B.
Also in the laminated body B after molding, no whitening was observed on the PC board, the transparency was high, and the PC board had good flatness without deformation or edge flow.

(Lamination Example C) Intermediate film 51 having the above three-layer structure
Were laminated in the same manner as in Lamination Example A except that the total thickness of this film was 1.2 mm, to obtain a laminate C.
Also in the laminated body C after molding, no whitening was recognized on the PC board, the transparency was high, and the PC board had good flatness without deformation or edge flow.

(Lamination Example D) Lamination was carried out except that an ordinary PVB adhesive film made of "ESREC Film" manufactured by Sekisui Chemical Co., Ltd. having a thickness of 0.4 mm was used instead of the acetal-based sound insulating PVB adhesive film. A laminate D was obtained in the same manner as in Example A.

(Lamination Example E) A lamination example except that a hot-melt urethane-based adhesive layer having a thickness of 0.8 mm was used as an intermediate layer between a glass plate and a PC plate, and an intermediate film having an acetal-based resin layer was not interposed. A laminate E was obtained in the same manner as in A.

(Lamination Example F) Instead of an intermediate film having an acetal-based resin layer as an intermediate layer between a glass plate and a PC plate and a hot-melt urethane-based adhesive layer, a thickness of 0.8 mm was used.
Made of Bridgestone's "PG16200"
A laminate F was obtained in the same manner as in the laminate example A, except that the film was used.

(Measurement of Warpage) The laminates A and D to F were compared with each other at room temperature (20 ° C.).
In accordance with JIS-R3202, a glass plate is set upright on a steel plate, a ruler is applied horizontally, and the amount of the glass plate pulled to the PC plate side with a length of 58 cm (the amount of warpage) is measured using a gauge. Was. The results are shown in Table 1 (warpage amount: mm),
The results are shown in Table 2 (warpage rate:%). The temperature in the table is the heating temperature during thermocompression bonding.

According to JIS-R3205 (standard for laminated glass), in the case of laminated laminated glass, the warpage rate is 0.5%.
Stipulated that it must not be exceeded. Table 1 shows the results of the warpage at room temperature.
Warpage tends to increase.

According to Table 2, the warpage ratio of the laminate A at a heating temperature of 125 ° C. is 0.17%, and even when a glass plate and a PC plate having a significantly different linear thermal expansion coefficient are laminated and solidified,
Organic / inorganic laminated glass that meets the standard can be produced. Conversely, even if the thickness of the intermediate layer is the same, the normal PV
Since the adhesive film B has no viscous property at room temperature, the effect of absorbing warpage is small (1.29%), and the effect of absorbing warpage at room temperature is small even when the thickness is increased (1.12).
%). This indicates that the intermediate film having the acetal-based resin layer is excellent in that it can secure the absorption of warpage due to its viscosity.

Tables 3 and 4 show the measurement results of the amounts of warpage and the rates of the laminates A to C in the same manner as in Tables 1 and 2. It can be seen that the more the interlayer film having the acetal-based resin layer is piled up, the more the warp is reduced, and that increasing the thickness of a viscous resin such as an acetal-based resin is excellent in preventing warpage.

Table 5 shows the cross sections shown in FIGS. 3 (a) and 3 (b).
The evaluation results of the water resistance performance of the laminates A and A 'having the end face configuration and the laminate A "having the cross-sectional end face configuration shown in Fig. 5 are different from those of the laminate A in the structure of the end face. It is obtained in the same manner as the laminate A except that it is exposed at the end face.

According to Table 5, the appearance of the laminate A ″ was abnormal in any of the evaluation results, whereas the appearance of the laminates A and A ′ was not changed at all. It can be seen that covering a PVB film with a good urethane adhesive layer that is weak against moisture penetration is excellent in water resistance.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

[Table 4]

[0047]

[Table 5]

[0048]

According to the present invention, an intermediate film having a resin layer having a higher viscosity at room temperature than the PVB film on the glass plate side between the glass plate and the PC plate, a urethane-based adhesive layer on the PC plate side, By adhering the intermediate layer via the intermediate layer so as to satisfy the above condition, it is possible to prevent the laminate from warping due to a difference in linear thermal expansion coefficient. Moreover, the intermediate layer in this case is a glass plate, P
Since both C-plates have excellent adhesive strength, while preventing appearance defects due to the warpage, the adhesive strength is increased to increase the impact resistance,
In addition, cloudiness of the PC board due to the intermediate layer can be prevented, and good transparency can be maintained for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an essential part showing an example of a transparent laminate of the present invention.

FIG. 2 is a schematic sectional view of an essential part showing an example of an intermediate film in the present invention.

FIG. 3 is a schematic cross-sectional view of a main part showing an example of the transparent laminate of the present invention.

FIG. 4 is a schematic cross-sectional view of an essential part showing an example of a lamination state in a lamination process of the transparent laminate of the present invention.

FIG. 5 is a schematic cross-sectional view of an essential part showing an example of a transparent laminate.

[Explanation of symbols]

 1: Glass plate 2: PV plate 3: Intermediate layer 10: Transparent laminate 41: Hot melt type urethane-based adhesive layer 51: Intermediate film

Claims (4)

[Claims] 1. A transparent laminate comprising a glass plate / intermediate film / hot melt type urethane adhesive layer / polycarbonate plate laminated in this order, wherein said intermediate film is a polyvinyl butyral film / polyvinyl butyral film at room temperature. A transparent laminate, wherein a resin layer / polyvinyl butyral film having a higher viscosity is laminated in this order. 2. The transparent laminate according to claim 1, wherein an end face of said intermediate film is covered with a hot-melt urethane-based adhesive layer. 3. The transparent laminate according to claim 1, wherein the thickness of the intermediate film is 0.2 to 1.3 mm, and the thickness of the hot-melt urethane-based adhesive layer is 0.1 to 0.8 mm. . 4. The transparent laminate according to claim 1, wherein the resin layer having a higher viscosity at room temperature than a polyvinyl butyral film is made of an acetal resin.