JPH04282243A - New laminated product - Google Patents

Abstract

PURPOSE:To prevent a laminated product from becoming white and also improve scratch resistance by laminating a polyvinylbutylal sheet layer and a glass sheet layer sequentially on a polycarbonate resin sheet layer having a weight average molecular weight of 40,000 or higher. CONSTITUTION:A polycarbonate resin sheet PC layer 3 having a weight average molecular weight of 40,000 or higher, a polyvinylbutylal sheet PVB layer 2 and a glass sheet layer 1 are stacked over each other. After this, this laminated product is placed in a decompressed atmosphere so that air is removed sufficiently from the inter-layer space and the layers are allowed to stick to each other under thermal pressurized conditions. The PC sheet layer recommended is a sheet having a weight average molecular weight of 20,000 or higher and biaxially stretched by a factor of 2 or more in terms of area ratio. The PVB sheet layer acts to adhere the glass sheet to the PC sheet layer, prevent the laminated product from cracking due to a bimetal effect during a cool/heat cycle test following the generation of a crack on account of a difference in the coefficients of thermal expansion of the glass sheet layer and the PC sheet layer, and improve the anti-impact properties of the laminated product.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate basically consisting of three layers: a glass sheet layer, a polyvinyl butyral sheet layer and a polycarbonate resin sheet layer. In particular, the present invention relates to a laminate that can be favorably used as a safety glazing material for public facilities, sports facilities, etc., for the purpose of reducing weight and improving safety, or as a safety glazing material for vehicles.

0002

BACKGROUND OF THE INVENTION Glass sheets are widely used as glazing materials. Glass has excellent rigidity, hardness, weather resistance, chemical resistance, etc., but it is also heavy and is less safe when broken due to collisions or earthquakes, so it has to be treated to block ultraviolet rays and infrared rays. It has some disadvantages.

On the other hand, polycarbonate resin (hereinafter abbreviated as PC) sheets are lighter than glass sheets, have excellent impact resistance, and are also easy to carry out ultraviolet and infrared blocking treatments by incorporating various additives. Excellent. Currently, in order to improve the safety of glass, especially its impact resistance and penetration resistance, laminated glass with a sheet of polyvinyl butyral resin (hereinafter abbreviated as PVB) sandwiched in between is being used as a safety glazing material for public facilities and sports facilities. Although they are used in various fields such as automobiles, there is a need for further improvements such as safety and weight reduction.

[0004] Particularly in recent years, glazing materials have been used in large quantities and in large areas in buildings such as public facilities and sports facilities, and as a result, there has been a demand for improved scratch resistance against humans. Additionally, glazing materials for automobiles are required to have improved scratch resistance for occupants in the event of a collision, and SAE Technical Papers
eries 840391 has Anti-Lace
Rative Windshield Mater
Glass (2.29mm)/PVB as ials
(0.95 mm) / glass (2.29 mm) / polyurethane (0.51 mm), and glass (
2.29mm) / PVB (0.95mm) / Glass (2
．． A six-layer structure of 29 mm)/PVB (0.38 mm)/polyester (0.13 mm)/hard cord has been announced.

[0005]

[Problem to be solved by the invention] However, these are made by adding polyurethane, polyester, etc. to conventional laminated glass, and are expensive, so there is a need for something with a simpler structure and improved scratch resistance against humans. It is being PVB is extremely tough and there is currently no better interlayer for safety glazing materials. PVB contains a large amount of plasticizer, and when PVB is used as an interlayer film, the transparent material in contact with it is required to have solvent resistance. Glass sheet layer, PVB layer, PC
Although a laminate consisting of layers is a highly desirable combination for safety glazing, the PC has been compromised by the PVB plasticizer and whitening has been a problem with long-term use. The present invention aims to solve the above problems.

[0006]

[Means for Solving the Problems and Effects] The present invention provides (1) a laminate having a glass sheet layer and a PC sheet layer having a weight average molecular weight of 40,000 or more via a PVB sheet layer as an intermediate layer; (2) an intermediate layer; A laminate (3) having a glass sheet layer and a PC sheet layer having a weight average molecular weight of 20,000 or more and biaxially stretched to an area ratio of 2 times or more through a PVB sheet layer. The thickness of the PVB sheet layer is 1 to 10 mm, the thickness of the PVB sheet layer is 0.1 to 1.5 mm, and the (1) or (2)
The thickness of the PC sheet layer described in ) is 0.01 to 5 mm, and (thickness of the glass sheet layer)/(the PC sheet layer described above)
The laminate according to item (1) or (2) above, wherein the ratio of thickness of the sheet layer is 1 or more.

The glass described in the present invention is a glass mainly composed of silicate glass, which is stabilized by containing ions such as sodium, potassium, lithium, calcium, magnesium, and strontium in the network structure of polymerized silicate groups. This is what I did. Soda lime glass is a typical glass. Phosphorsilicate glass, borosilicate glass, etc., which have a network copolymerized with silicate, can also be used. Lead alkali glass, alumina silicate glass, and quartz glass consisting only of SlO2 can also be used.

[0008] As the glass, tempered glass, semi-tempered glass, partially tempered glass, unstrengthened glass, etc. can be used as required. The PC resin described in the present invention has transparency, weather resistance, hardness,
Among synthetic resins, it is one of the most excellent glazing materials in terms of bending strength and bending rigidity. As the PC, aromatic PC can be favorably used in the present invention.
In particular, the following PC synthesized from bisphenol A can be used more favorably.

[0009]

[Chemical formula 1]

[0010] Furthermore, a polymer blend containing the above-mentioned PC as a main ingredient is also included within a range that does not reduce the transparency of the PC. In this case, the above-mentioned PC is contained in an amount of 70% by weight or more, preferably 90% by weight or more. The weight average molecular weight of the polymer blend must be 40,000 or more. Moreover, the biaxially stretched one may be 20,000 or more. In the present invention, PC with a polymerization degree of 20,000 or 40,000 or more in weight average molecular weight refers to PC with a polymerization degree of 20,000 or 40,000 or more in weight average molecular weight measured by gel permeation chromatography of a tetrahydrofuran solution of PC. be.

[0011] In the present invention, it is preferable that the molecular weight of PC is larger. If the weight average molecular weight is less than 20,000, no orientation effect will appear even if biaxially stretched, so there will be almost no improvement in solvent resistance even if biaxially stretched, and the resulting laminate will have a P
When C is exposed to PVB, whitening may occur or impact resistance may be insufficient. The biaxially stretched PC sheet preferably has a weight average molecular weight of 25,000 or more. When an unstretched PC sheet is used in the laminate of the present invention, the weight average molecular weight of the PC is 40,000 or more, preferably 50,000 or more, and more preferably 60,000 or more. Moreover, 500,000 or less is preferable. If the weight average molecular weight of the unstretched PC sheet is less than 40,000, the solvent resistance will be insufficient when used in a laminate, and whitening will occur during use.

[0012] PC having a large molecular weight is disclosed in, for example, Japanese Patent Application Laid-open No.
It can be produced by the following method described in Japanese Patent No.-158033. That is, 85 mol% or more of dihydroxydiarylalkane represented by the general formula HO-Ar1-Y-Ar2-OH (Ar1 and Ar2 in the formula are each an arylene group and Y is an alkylene or substituted alkylene group) and the dihydroxydiaryl In producing an aromatic polycarbonate by reacting a dihydroxydiaryl compound containing 15 mol% or less of a dihydroxydiaryl compound other than an alkane with a diaryl carbonate,
(a) The dihydroxydiaryl compound and the diaryl carbonate are prepolymerized under heating to obtain an aryl compound having a weight average molecular weight (Mw) in the range of 2,000 to 20,000 and occupying all terminal groups. a prepolymerization step of preparing a prepolymer having a proportion of carbonate group terminals of more than 50 mol %; (b) crystallizing the prepolymer to prepare a crystallized prepolymer having a degree of crystallinity in the range of 5 to 55%; and (c) heating the crystallized prepolymer to a temperature above the glass transition temperature of the aromatic polycarbonate to be produced and within a range where the crystallized prepolymer can maintain a solid state. This is a method for producing an aromatic polycarbonate, which is characterized by sequentially performing solid phase polymerization steps to further increase the degree of polymerization.

[0013] The present invention also includes PC in which a small amount of crosslinking exists. Further, high molecular weight PC having appropriate branching can also be used satisfactorily in the present invention. When the weight average molecular weight is 100,000 or more, it becomes difficult to form a sheet by heating and melting, but in this case, the sheet can be formed by the so-called solvent casting method, in which the sheet is formed by dissolving it in a solvent. In the present invention, ultra-high molecular weight PC, which is difficult to melt-extrude, can also be used satisfactorily.

[0014] Various additives can be added to PC within a range that does not significantly reduce its transparency. For example, ultraviolet absorbers, dyes and pigments, stabilizers, etc. can be added. The ultraviolet absorber here refers to 2,2'-dihydroxy-4-
Methoxybenzophenone, 2,2'-dihydroxy-4
, 4'-dimethoxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methyl phenol) 5-chlorobenzotriazole, 2-(2-hydroxy-3'
, 5-di-tert-butylphenol) 5-chlorobenzotriazole, and substituted acrylonitrile.

Among them, triazoles are particularly effective, such as 2-(2-hydroxy-5'-methylphenyl)
Benzotriazole, 2-(2'-hydroxy-3'-
Tert-butyl-5'-methylphenol) 5-chlorobenzotriazole is highly effective. Biaxial stretching of PC can be carried out by various methods, but known tension stretch molding methods, compression stretch molding methods, roll rolling molding methods, inflation molding methods, in-die extrusion stretch molding methods, etc. are effective.

Among these, the compression stretch molding method disclosed in JP-A-60-149420, the method disclosed in JP-A-60-168624,
The in-die extrusion stretch molding method shown in the publication can be effectively used. In the present invention, an area ratio stretching ratio of 2 times or more, preferably 3 times or more, and more preferably 4 times or more is effective. The present invention also includes slightly non-uniform biaxially oriented sheets, commonly referred to as biaxially oriented sheets.

As the PVB described in the present invention, a PVB film generally used as an interlayer film for laminated glass can be used, and the molar ratio of hydroxyl groups, acetyl groups, and butyral groups in PVB is 25 to 50:1 to 5:40. The following PVB of about 70 is best used.

[0018]

[Case 2]

The performance of PVB varies depending on the degree of polymerization of PVB, the molar ratio of hydroxyl groups/acetyl groups/butyral groups, plasticizer, etc.
can be used best. In the present invention, the thickness of the glass sheet layer is preferably 1 to 10 mm, more preferably 2 to 6 mm. Moreover, 3-5 mm is especially preferable. 1m
If it is less than 10 mm, it will easily break, and if it is more than 10 mm, there will be no weight reduction effect. The thickness of the PVB sheet layer is determined with the aim of improving the impact resistance of the laminate of the present invention through its impact absorption performance and alleviating the occurrence of internal stress in the laminate due to the aforementioned temperature change. is 0.1 ~ 1.5m
It is m. If the thickness is less than 0.1 mm, the impact absorption performance is low, and if it exceeds 1.5 mm, it is unnecessary. 0.3-1.
The thickness is preferably 2 mm, and more preferably 0.3 to 0.8 mm.

[0020] The thickness of the PC sheet layer is 0.01 to 5 mm.
It is. If it is less than 0.01 mm, the purpose of the laminate of the present invention cannot be achieved, and if it exceeds 5 mm, the laminate will generate more internal stress due to temperature changes, and will be more likely to break at low temperatures. 0.05 mm to 2 mm is preferable, and 0.1 to 1
More preferably, it is mm. Furthermore, when comparing the glass sheet layer and the PC sheet layer, the glass sheet layer with a smaller elongation at break is more likely to break. Therefore (glass sheet layer)/(
When the ratio of PC sheet layer) is preferably 1 or more, more preferably 3 or more, it becomes difficult to crack when internal stress occurs.

[0021] The present invention provides a glass sheet layer, an intermediate layer of PV
It basically consists of three layers: B sheet layer and PC sheet layer.
Further layers can be formed as necessary. In particular, it is preferable to apply a rigid coat layer to the surface of the PC sheet layer. A rigid coat layer is generally a thin transparent cured layer with a thickness of 1 to 50 μm that is coated on the surface of a transparent synthetic resin to harden the surface of the synthetic resin and improve scratch resistance. Organosiloxane rigid coat layers are generally widely used and can be used satisfactorily in the present invention. The rigid coat layer preferably has a pencil hardness of 4H or more, more preferably 5H or more.

[0022] The polyfunctional acrylate rigid coat layer described herein can be prepared by applying a polyfunctional acrylate rigid coat paint containing a polyfunctional acrylate compound as a main component to the surface of a synthetic resin base material by dipping, spinning, spraying, etc.
It is formed by coating using a method such as a curtain flow method and then curing it mainly by irradiating ultraviolet rays. Polyfunctional acrylate compounds have multiple acryloyloxy or methacrylooxy groups (CH
2 = CR-COO-, R is H or CH3), and is also generally called an oligoacrylate. Examples of polyfunctional acrylate compounds are shown below. 1) Polyol acrylate 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetramethacrylate, etc. 2) Polyester acrylate α,ω-tetraacrylic bistrimethylolpropane tetrahydro Phthalate, α,ω-dimethacrylic bisdiethylene glycol phthalate, etc. 3) Urethane acrylate A compound in which 2-hydroxyethyl acrylate (HEA) is reacted with tolylene diisocyanate, isophorone diisocyanate, etc., a compound in which hexanediol, isophorone diisocyanate, and HEA are reacted. Compounds etc. 4) Diacrylate of epoxy acrylate bisphenol A dicrycidyl ether, trimethylolpropane polyglycidyl ether polyacrylate, etc. 5) Others such as spiroglycol diglycidyl ether diacrylate, silicone acrylate, trisacryloyloxyethyl isocyanurate, etc. Among the functional acrylate compounds, compounds with excellent UV curability in air, such as pentaerythritol acrylate, can be used particularly well.

For UV curing, a photopolymerization initiator or photosensitizer, typically a benzophenone or acetophenone substance, is added to the polyfunctional acrylate hard coat paint. In addition, various additives such as antioxidants, light stabilizers, thermal polymerization inhibitors, stabilizers such as ultraviolet absorbers, coloring agents, and fluorine-based or silicon-based additives may be added as necessary. A small amount of surfactant etc. is added.

The polyorganosiloxane rigid coat layer may be one using methyltrialkoxysilane and phenyltrialkoxysilane as starting materials, a combination of these with tetraalkoxysilane, or a mixture with other resin coatings. , for example methyltriethoxysilane/phenyltriethoxysilane reaction mixture (USP 34
51838), partial hydrolyzate of methyltriethoxysilane/acetic acid/sodium naphthenate (JP-A-50-143
No. 822), methyltrimethoxysilane/tetraethoxysilane/dimethylpolysiloxane having hydroxyl groups at both terminals/acidic catalyst reaction mixture (JP-A-50-116600).

[0025] Tetraalkoxysilane hydrolyzate/alkyltrialkoxysilane hydrolyzate/alkali metal salt mixture of organic carboxylic acid (JP-A-48-56230)
In addition, those starting from polyorganosiloxanes having functional groups such as vinyl groups, epoxy groups, and amino groups, such as hydrolysates of copolymers of vinyl alkoxysilane and vinyl acetate/alkyl silicate. hydrolyzate/vinyl acetate or acrylic acid, methacrylic acid, esters thereof/boron trifluoride monoethylamine complex (JP-A-48-26221).

γ-glycidoxyalkyltrialkoxysilane ring-opening polymer (Japanese Patent Application Laid-Open No. 50-40674), β-
A reaction mixture of one or more of (3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and vinyltrimethoxysilane (JP 50-69174), β-(3 ，
4-epoxycyclohexyl)ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane.

A reaction mixture of one or more vinyltrimethoxysilanes and an epoxy prepolymer, diallyl phthalate, glycidyl methacrylate, etc.
0-69184), (2,3-epoxypropoxy)
Methyltrimethoxysilane/glycidyl methacrylate reaction mixture (JP-A-50-78639), aminoalkylalkoxysilane/epoxyalkylalkoxysilane partial hydrolysis reaction mixture (JP-A-48-84878)
), etc. are used.

The laminate of the present invention may have two or more PC sheet layers, if necessary. To explain this with reference to FIG. 7 as an example, for example, an unstretched PC layer 3 having a weight average molecular weight of 40,000 or more is on the side in contact with the PVB layer 2, and a PC layer 5 having a weight average molecular weight of less than 40,000 on the outside thereof. Can be layered. For example, a PC layer laminated with a 0.05 mm thick PC sheet layer with a viscosity average molecular weight of 250,000 on the side in contact with the PVB sheet and a 0.3 mm thick PC sheet with a weight average molecular weight of 30,000 on the outside can be used satisfactorily.

A biaxially stretched PC sheet is also used on the side in contact with the PVB sheet based on the same technical concept, and
A C layer can also be used on the outside. That is, the PC sheet specified in the claims of the present invention needs to be used on the side that is in contact with the PVB sheet. The total thickness of the PC layer consisting of two or more layers of PC sheets is more than 0.01 and within 5 mm, and among the two or more layers, the thickness of the PC sheet specified in the claims of the present invention is also 0.01 mm. The diameter is selected within the range of 0.01 to less than 5 mm.

The PVB sheet layer has the function of adhering the glass sheet layer and the PC sheet layer, and also prevents cracking due to the bimetallic effect during thermal cycle tests caused by the difference in thermal expansion coefficient between the glass sheet layer and the PC sheet layer. It has the function of improving the impact resistance of the laminate of the invention. As a method for adhering a glass sheet layer and a PC sheet layer well through a PVB sheet layer, after overlapping the glass sheet layer, PVB sheet layer, and PC sheet layer, the laminate is placed under reduced pressure, and the interlayer There is a method of adhering under heat and pressure after sufficiently removing air.

[0031] In this heating and pressure bonding process, since the PVB sheet exhibits adhesive performance in a temperature range of 80°C or higher, the laminate obtained by the above process is fixed in a temperature range of 80°C or higher. When the temperature is returned to room temperature after the bonding process is completed, the temperature change causes a difference in the amount of shrinkage due to the difference in thermal expansion coefficient between the glass sheet layer and the PC sheet layer, and as a result, the bimetallic effect causes the laminate to shrink. Internal stress occurs. If the temperature is lowered further, internal stress will increase and cracks will occur in the glass sheet.

[0032] When the present invention is used as a safety glazing material for buildings, automobiles, etc., it may be used in a temperature range of -40 to 100°C, considering changes in outside air temperature and the influence of direct sunlight. Conceivable. In this temperature range, it is necessary to minimize the internal stress of the laminate, especially the internal stress generated in the glass sheet.In order to prevent the glass sheet from cracking, the internal stress of the laminate must be It is preferable that the temperature at which the temperature becomes substantially zero exists in the central temperature range of the temperature range, that is, in the range of -10°C or more and less than 50°C.

For example, P
When adhering the glass sheet layer and the PC sheet layer through the VB sheet layer, an external force is applied in advance when fixing in a temperature range of 80°C or higher. Fix it so that it is located on the concave side,
■In the case of a curved laminate where the glass sheet is located on the convex side of the curved surface, fix the laminate with the radius of curvature larger than the specified radius of curvature; In the case of a curved laminate, by fixing the curvature radius smaller than a predetermined radius of curvature, the temperature at which the internal stress of the finished laminate becomes substantially 0 can be set at -10°C or higher and lower than 50°C. temperature range.

The present invention will be explained in detail below with reference to the drawings. Each figure schematically shows a part of the cross section of the laminate of the present invention. 1, 2 and 7 are planar laminates, FIGS. 3 and 4 are curved laminates in which the glass sheet layer is located on the convex side of the curved surface, and FIGS. 5 and 6 are in which the glass sheet layer is located on the concave side of the curved surface. It is a curved laminate located at . The present invention includes:
In this way, curved laminates are also included.

In each figure, 1 is a glass sheet layer, 2 is a PVB sheet layer, and 3 is a viscosity average molecular weight of 40,000 or more or the same,
4 is a rigid coat layer, and 5 is an unstretched PC layer having a weight average molecular weight of less than 40,000.

[0036]

[Example] In the following example, a planar laminate will be explained for the purpose of clarifying the contents of the present invention.
It is also fully applicable to quadratic curved laminates and tertiary curved laminates. In this example, the following sheets were used to constitute each layer. Glass sheet: Untempered glass sheet PV of soda glass
B sheet: Sekisui Chemical Co., Ltd. "S-LEC Film" HI type PC sheet with a viscosity average molecular weight of 50,000: JP-A-1-158
A PC sheet with a weight average molecular weight of 50,000 manufactured by the method disclosed in Publication No. 033 was compression molded into a non-stretched sheet. 0.2 mm thick unstretched sheet made of PC "Macroron 5900" Biaxially stretched PC sheet: Manufactured by Kanchu Plastic Industry Co., Ltd. 2
mm thick "Sunroid Polycarbonate Ace" was published in 1986-1
Biaxially stretched to 5 times the area ratio to 0.4 mm using the compression stretch molding method disclosed in Japanese Patent No. 49420.

The weight average molecular weight of PC is 25,000. PC sheet with a weight average molecular weight of 25,000: An unstretched PC sheet with a weight average molecular weight of 25,000, 0.4 mm thick.

[0038]

[Example 1] A 3 mm thick glass sheet, a 0.38 mm thick PVB sheet, and a 0.4 mm thick PC sheet with a weight average molecular weight of 50,000 are stacked on top of each other, and the whole is placed in a vacuum pack bag.
After evacuating the inside of the vacuum pack bag, the vacuum pack is sealed. The laminate was placed horizontally in an autoclave with the glass side up and the PC side down, and a load was applied from above to the center of the glass to bend it so that the glass side was concave and the PC side was convex. ℃ and a pressure of 10 kg/cm 2 for 10 minutes to bond. After cooling to 50°C, it was taken out from the autoclave to obtain a laminate of the present invention.

The laminate was horizontal at room temperature, had no residual stress, and was good as a safety glazing material. Even when the laminate was peeled off after one month, there was no evidence that the PC had been damaged by PVB, and its solvent resistance was good. Furthermore, place JIS R on the laminate with the PC sheet side facing up.
When the head form test shown in 3212 was conducted,
Although there were honeycomb-shaped cracks in the glass, there were no cracks in the PC and PVB, making it a safe glazing material with excellent scratch resistance for automobiles, etc.

[0040]

[Example 2] As a PC sheet, the weight average molecular weight is 25
A laminate was molded in the same manner as in Example 1 using 10,000 PC sheets. The laminate was also tested for the same items as in Example 1, and it was found to be an excellent safety glazing material as in Example 1.

[0041]

[Example 3] A PC sheet with a weight average molecular weight of 2.
A laminate was formed using 50,000 biaxially stretched PC sheets and tested in the same manner as in Example 1, and it was found to be an equally excellent safety glazing material.

[0042]

[Comparative Example 1] As a PC sheet, the weight average molecular weight was 2.
A laminate was molded in the same manner as in Example 1 using 50,000 PC sheets. When the laminate is peeled off one month after molding, the PC
The sheet has been eroded by PVB and whitening has occurred.
It could not be used as a safety glazing material for a long period of time.

[0043]

[Effects of the Invention] The laminate of the present invention has significant effects such as preventing whitening, improving scratch resistance during collisions, and reducing weight. Therefore, it is preferably used as a safety glazing material for automobiles, such as windshields, sunroofs, rear windows, side windows, etc. In addition, it is lightweight and can be used as a safety glazing material for public facilities, sports facilities, etc.
Can be used successfully for safety purposes.

[Brief explanation of the drawing]

FIG. 1 schematically shows a part of a cross-sectional view of an example of a laminate of the present invention.

FIG. 2 schematically shows a part of a cross-sectional view of an example of a laminate of the present invention.

FIG. 3 schematically shows a part of a cross-sectional view of an example of the laminate of the present invention.

FIG. 4 schematically shows a part of a cross-sectional view of an example of the laminate of the present invention.

FIG. 5 schematically shows a part of a cross-sectional view of an example of the laminate of the present invention.

FIG. 6 schematically shows a part of a cross-sectional view of an example of a laminate of the present invention.

FIG. 7 schematically shows a part of a cross-sectional view of an example of a laminate of the present invention.

[Explanation of symbols]

1 Glass sheet layer 2 Polyvinyl butyral sheet layer 3 Polycarbonate resin sheet layer 4 Rigid coat layer

Claims (3)

[Claims] 1. A laminate comprising a glass sheet layer and a polycarbonate resin sheet layer having a weight average molecular weight of 40,000 or more, with a polyvinyl butyral sheet layer as an intermediate layer interposed therebetween. [Claim 2] A polycarbonate resin sheet layer having a weight average molecular weight of 20,000 or more and biaxially stretched to an area ratio of at least twice that of the glass sheet layer through the intermediate polyvinyl petral sheet layer. A laminate having. [Claim 3] The thickness of the glass sheet layer is 1 to 10 mm.
, the thickness of the polyvinyl butyral sheet layer is 0.1 to 1.
5mm, thickness of polycarbonate resin sheet layer is 0.0
1 to 5 mm, and (thickness of glass sheet layer)/
The laminate according to claim 1 or 2, wherein the ratio of (thickness of the polycarbonate resin sheet layer) is 1 or more.