Method for manufacturing glass resin laminate

Abstract

To provide a method for manufacturing a glass resin laminate which is capable of suppressing generation of bubble defects better than before even if an adhesive layer is thin in the case of laminating the glass film and a resin film via an adhesive layer.SOLUTION: A method for manufacturing the glass resin laminate 1 has a step of sandwiching a glass film 10 and a resin film 20 between a first roll pressurizing the resin film and a second roll which is arranged opposing the first roll and pressurizes the glass film and adhering the films via an adhesive layer 21, where a surface layer of the first roll is formed of a resin material having a lower elastic modulus than iron, the resin material is polyethylene terephthalate, polyethylene or polypropylene, and when the elastic modulus of the surface layer of the first roll is P1 and the elastic modulus of the resin film is P2, a ratio of the elastic modulus P1 to the elastic modulus P2 (P1 / P2) satisfies 3×10-3≤P1 / P2≤1.0.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a glass resin laminate.

Background Art

[0002] In recent years, liquid crystal cells equipped with a touch sensor function on the screen have been increasingly used in a wide range of fields from mobile phones to information displays.

[0003] As an example, there is a display panel in which a film or glass having a sensor function is laminated on a polarizing plate, and a tempered glass called a front panel is disposed on the outermost layer via an adhesive layer for filling the step on the sensor surface. Also, recently, a liquid crystal panel called an in-cell in which a touch sensor is incorporated into a glass substrate of a liquid crystal cell has appeared from the viewpoints of thinning and weight reduction.

[0004] On the other hand, although the thinning of tempered glass has progressed, tempered glass self-destructs due to the compressive stress of the glass when it becomes 300 μm or less, so there is a limit to thinning. Under such circumstances, hardening of the front panel using resin has been studied, but the actual situation is that sufficient hardness cannot be obtained.

[0005] Therefore, a thin glass film has been attracting attention as a front panel of a liquid crystal cell. This glass film is laminated with a resin film including a polarizing plate via an adhesive layer, for example. Due to requirements such as thinning of the product, the adhesive layer tends to be thin.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Incidentally, the lamination of the glass film and the resin film is performed, for example, while being sandwiched between two rolls arranged adjacent to each other vertically. At this time, if foreign matter adheres to the surface of the roll on the side in contact with the resin film, the highly rigid glass film hardly deforms, and the resin film with low rigidity mainly deforms.

[0008] Therefore, unevenness corresponding to the shape of the foreign matter occurred on the side of the resin film in contact with the glass film, and air might enter the concave portion to cause a bubble defect. In particular, when the thickness of the adhesive layer was thin, the generation of bubble defects was remarkable. As a product, the fewer the number of bubble defects, the more preferable.

[0009] The present invention has been made in view of the above points, and an object thereof is to provide a method for manufacturing a glass resin laminate capable of suppressing the occurrence of bubble defects more than before even when the adhesive layer is thin when laminating a glass film and a resin film via the adhesive layer.

Means for Solving the Problems

[0010] The method for manufacturing the present glass resin laminate includes a step of sandwiching a glass film and a resin film between a first roll that presses the resin film and a second roll that is arranged to face the first roll and presses the glass film, and bonding them via an adhesive layer. In the method for manufacturing a glass resin laminate, the surface layer of the first roll is formed of a resin material having a lower elastic modulus than iron, the resin material is polyethylene terephthalate, polyethylene, or polypropylene, and when the elastic modulus of the surface layer of the first roll is P1 and the elastic modulus of the resin film is P2, the ratio P1 / P2 of the elastic modulus P1 to the elastic modulus P2 satisfies 3×10 -3 ≦P1 / P2≦1.0.

Advantages of the Invention

[0011] According to the disclosed technique, it is possible to provide a method for manufacturing a glass resin laminate capable of suppressing the occurrence of bubble defects more than before even when the adhesive layer is thin when laminating a glass film and a resin film via the adhesive layer.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In each drawing, the same reference numerals are assigned to the same components, and redundant descriptions may be omitted.

[0014] (Glass Resin Laminate) First, the glass resin laminate to be manufactured will be described. FIG. 1 is a cross-sectional view illustrating the glass resin laminate. FIG. 1(a) shows the glass film and the resin film before lamination, and FIG. 1(b) shows the glass film and the resin film after lamination (i.e., the glass resin laminate).

[0015] The glass resin laminate 1 has a glass film 10 and a resin film 20. The glass film 10 is bonded to the resin film 20 via an adhesive layer 21 of the resin film 20.

[0016] The glass film 10 is not particularly limited, and an appropriate one can be adopted according to the purpose. According to the classification by composition, the glass film 10 includes, for example, soda-lime glass, borate glass, aluminosilicate glass, fused silica glass, etc. Also, according to the classification by alkali component, it includes alkali-free glass and low-alkali glass. The content of the alkali metal component (e.g., Na2O, K2O, Li2O) of the above glass is preferably 15% by weight or less, more preferably 10% by weight or less.

[0017] The thickness of the glass film 10 is preferably 50 μm to 150 μm, more preferably 60 μm to 140 μm, still more preferably 70 μm to 130 μm, and particularly preferably 80 μm to 120 μm. If it is within such a range, the glass film has excellent flexibility and can be processed by a roll-to-roll process, and a glass resin laminate 1 that is difficult to crack and has excellent productivity can be obtained.

[0018] The light transmittance of the glass film 10 at a wavelength of 550 nm is preferably 85% or more. The refractive index of the glass film 10 at a wavelength of 550 nm is preferably 1.4 to 1.65.

[0019] The density of the glass film 10 is preferably 2.3 g / cm 3 ~3.0 g / cm 3 and more preferably 2.3 g / cm 3 ~2.7 g / cm 3 If it is a glass film within the above range, a glass resin laminate 1 that can contribute to weight reduction of image display can be provided.

[0020] The method for forming the glass film 10 is not particularly limited, and an appropriate method can be adopted according to the purpose. Typically, the glass film 10 can be produced by melting a mixture containing main raw materials such as silica and alumina, defoaming agents such as sodium sulfate and antimony oxide, and reducing agents such as carbon at a temperature of about 1400°C to 1600°C, forming it into a thin plate shape, and then cooling. Examples of the method for forming the glass film 10 include the slot down-draw method, the fusion method, the float method, etc. The glass film formed into a plate shape by these methods may be chemically polished with a solvent such as hydrofluoric acid as necessary to make it thinner or improve its smoothness.

[0021] The resin film 20 includes an adhesive layer 21, a polarizing plate 22, an adhesive layer 28, and a release film 29 in this order. However, the resin film 20 may further include other layers. For example, the resin film 20 can include a retardation layer between the polarizing plate 22 and the adhesive layer 28, but is not limited thereto.

[0022] In addition, the adhesive layer 21 may be provided on the glass film 10. In this case, the resin film 20 includes a polarizing plate 22, an adhesive layer 28, and a release film 29 in this order, and may include other layers as necessary.

[0023] The elastic modulus of the resin film 20 is preferably 0.1 GPa to 8.0 GPa, more preferably 0.2 GPa to 7.0 GPa, and still more preferably 0.3 GPa to 5.0 GPa. In this specification, the elastic modulus can be measured using an autograph under the following conditions.

[0024] [Elastic Modulus Measurement Method] Measurement Temperature: 23°C Sample Size: Width 2 cm, Length 15 cm Chuck Distance: 10 cm Tensile Speed: 10 mm / min.

[0025] In this specification, the adhesive layer refers to a layer that has adhesiveness at normal temperature and adheres to an adherend under a light pressure. Therefore, even when the adherend adhered to the adhesive layer is peeled off, the adhesive layer retains a practical adhesive force. On the other hand, the adhesive layer refers to a layer that can bond substances by intervening between the substances. Therefore, when the adherend adhered to the adhesive layer is peeled off, the adhesive layer does not have a practical adhesive force.

[0026] The polarizing plate 22 is disposed on the side opposite to the side where it is adhered to the glass film 10 of the adhesive layer 21. The polarizing plate 22 has a polarizer 221, a first protective film 222, and a second protective film 223. The first protective film 222 is disposed on the adhesive layer 21 side of the polarizer 221, and the second protective film 223 is disposed on the adhesive layer 28 side of the polarizer 221.

[0027] The release film 29 is disposed on the side opposite to the polarizer 221 of the second protective film 223 via the adhesive layer 28.

[0028] Hereinafter, each component of the resin film 20 will be described in more detail.

[0029] [Adhesive layer] The adhesive layer 21 is not particularly limited, and an appropriate adhesive can be adopted according to the purpose. Examples of the adhesive include polyester-based adhesives, polyurethane-based adhesives, polyvinyl alcohol-based adhesives, and epoxy-based adhesives. Among these, epoxy-based adhesives, which can obtain particularly good adhesion, are preferred.

[0030] When the adhesive layer 21 is a thermosetting adhesive, it can exhibit peel resistance by heating and curing (solidifying). Also, when the adhesive layer 21 is a photocuring adhesive such as an ultraviolet curing type, it can exhibit peel resistance by irradiating light such as ultraviolet light for curing. Also, when the adhesive layer 21 is a moisture-curing adhesive, since it can react with moisture in the air and cure, it can also cure by being left alone and exhibit peel resistance.

[0031] The adhesive layer 21 may use, for example, a commercially available adhesive, or various curable resins may be dissolved or dispersed in a solvent to prepare an adhesive solution (or dispersion).

[0032] The thickness of the adhesive layer 21 is preferably 8 μm or less, more preferably 0.1 μm to 8 μm, still more preferably 0.1 μm to 5 μm, and particularly preferably 0.1 μm to 2 μm. If it is within such a range, a glass resin laminate 1 excellent in flexibility and puncture resistance can be obtained. Also, since the thinner the adhesive layer 21, the thinner the glass resin laminate 1, it can meet the requirement of thinning the product.

[0033] The elastic modulus of the adhesive layer 21 is preferably 0.5 GPa to 15 GPa, more preferably 0.8 GPa to 10 GPa, still more preferably 1 GPa to 5 GPa. If it is within such a range, a glass resin laminate 1 excellent in flexibility and puncture resistance can be obtained.

[0034] In the state of Fig. 1(a) (before lamination), the adhesive layer 21 is uncured. After laminating the glass film 10 on the resin film 20 as shown in Fig. 1(b), it is cured to obtain a glass resin laminate 1 in which the glass film 10 and the resin film 20 are bonded together. The manufacturing method of the glass resin laminate 1 for bonding the glass film 10 and the resin film 20 via the adhesive layer 21 will be described later.

[0035] [Polarizer] The thickness of the polarizer 22 is preferably 5 μm to 300 μm, more preferably 10 μm to 250 μm, still more preferably 25 μm to 200 μm, and particularly preferably 25 μm to 100 μm.

[0036] The elastic modulus of the polarizer 22 is preferably 1 GPa or more, more preferably 1 GPa to 10 GPa, still more preferably 2 GPa to 7 GPa, and particularly preferably 2 GPa to 5 GPa. If it is within such a range, a glass resin laminate 1 excellent in puncture resistance can be obtained.

[0037] The shape of the polarizing plate 22 is not particularly limited, and an appropriate shape can be adopted according to the purpose. As an example, a rectangular shape having a long side and a short side can be mentioned. When the polarizing plate 22 has a rectangular shape, it is preferable that the absorption axis direction of the polarizer 221 included in the polarizing plate 22 and the long side or the short side of the polarizing plate 22 are substantially parallel. In this specification, "substantially parallel" is a concept that includes not only the case of being exactly parallel but also the case where the angle formed by the two lines is ±10° (preferably ±5°).

[0038] [Polarizer] The thickness of the polarizer 221 is not particularly limited, and an appropriate thickness can be adopted according to the purpose. The thickness of the polarizer 221 is typically about 1 μm to 80 μm. A thin polarizer may be used as the polarizer 221. In this case, the thickness of the polarizer 221 is preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less, and particularly preferably 6 μm or less.

[0039] The polarizer 221 preferably exhibits absorption dichroism at any wavelength in the range of 380 nm to 780 nm. The single transmittance of the polarizer is preferably 40.0% or more, more preferably 41.0% or more, still more preferably 42.0% or more, and particularly preferably 43.0% or more. The degree of polarization of the polarizer 221 is preferably 99.8% or more, more preferably 99.9% or more, still more preferably 99.95% or more.

[0040] The polarizer 221 is preferably an iodine-based polarizer. More specifically, the polarizer can be composed of a polyvinyl alcohol-based resin (hereinafter referred to as "PVA-based resin") film containing iodine.

[0041] The PVA-based resin for forming the PVA-based resin film is not particularly limited, and an appropriate resin can be adopted according to the purpose. For example, polyvinyl alcohol and ethylene-vinyl alcohol copolymer can be mentioned.

[0042] Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. Ethylene-vinyl alcohol copolymer is obtained by saponifying ethylene-vinyl acetate copolymer. The saponification degree of PVA-based resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, and more preferably 99.0 mol% to 99.93 mol%. The saponification degree is determined according to JIS K 6726-1994. By using a PVA-based resin with such a saponification degree, a polarizer with excellent durability can be obtained. If the saponification degree is too high, there is a risk of gelation.

[0043] The average degree of polymerization of the PVA-based resin is not particularly limited and can be appropriately selected according to the purpose. The average degree of polymerization of the PVA-based resin is, for example, 1000 to 10000, preferably 1200 to 5000, and more preferably 1500 to 4500. The average degree of polymerization is determined according to JIS K 6726-1994.

[0044] Examples of the method for producing the polarizer 221 include a method (I) of stretching and dyeing a single PVA-based resin film, a method (II) of stretching and dyeing a laminate (i) having a resin substrate and a polyvinyl alcohol-based resin layer, etc. Since method (I) is a well-known and commonly used method in the industry, a detailed description is omitted.

[0045] Method (II) preferably includes a step of stretching and dyeing a laminate (i) having a resin substrate and a polyvinyl alcohol-based resin layer formed on one side of the resin substrate to produce a polarizer on the resin substrate. The laminate (i) can be formed by applying and drying a coating solution containing a polyvinyl alcohol-based resin on the resin substrate. Also, the laminate (i) may be formed by transferring a polyvinyl alcohol-based resin layer onto the resin substrate. The details of the above production method (II) are described, for example, in Japanese Patent Application Laid-Open No. 2012-73580, which is incorporated herein by reference.

[0046] [First and Second Protective Films] The first protective film 222 and the second protective film 223 are not particularly limited, and an appropriate resin film can be adopted according to the purpose. As the forming materials of the first protective film 222 and the second protective film 223, for example, polyester resins such as polyethylene terephthalate (PET), cellulose resins such as triacetyl cellulose (TAC), cycloolefin resins such as norbornene resins, olefin resins such as polyethylene and polypropylene, (meth)acrylic resins, etc. can be mentioned. Among these, preferably, it is polyethylene terephthalate (PET). Note that the “(meth)acrylic resin” refers to an acrylic resin and / or a methacrylic resin.

[0047] As the (meth)acrylic resin, for example, a (meth)acrylic resin having a glutarimide structure is used. The (meth)acrylic resin having a glutarimide structure (hereinafter also referred to as a glutarimide resin) is described in, for example, JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-328334, JP-A-2006-337491, JP-A-2006-337492, JP-A-2006-337493, JP-A-2006-337569, JP-A-2007-009182, JP-A-2009-161744, JP-A-2010-284840. These descriptions can be incorporated herein by reference.

[0048] The first protective film 222 and the second protective film 223 and the polarizer 221 can be laminated via any appropriate adhesive layer. The resin substrate used in the production of the polarizer 221 is peeled off before or after laminating the first protective film 222 and the second protective film 223 and the polarizer 221.

[0049] The thickness of the first protective film 222 and the second protective film 223 is preferably 4 μm to 250 μm, more preferably 5 μm to 150 μm, still more preferably 10 μm to 100 μm, and particularly preferably 10 μm to 50 μm.

[0050] The elastic modulus of the first protective film 222 and the second protective film 223 is 1 GPa or more, preferably 1 GPa to 10 GPa, more preferably 1.8 GPa to 7 GPa, and still more preferably 2 GPa to 5 GPa. If it is in such a range, the glass resin laminate 1 excellent in puncture resistance can be obtained.

[0051] [Adhesive layer] The adhesive layer 28 can be formed from any suitable adhesive. As the adhesive, for example, adhesives based on polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluorine-based and rubber-based polymers are used. Preferably, an acrylic adhesive is used. This is because acrylic adhesives are excellent in optical transparency, exhibit adhesive properties of appropriate wettability, cohesiveness, and adhesiveness, and can be excellent in weather resistance and heat resistance. In particular, an acrylic adhesive composed of an acrylic polymer having 4 to 12 carbon atoms is preferable.

[0052] The thickness of the adhesive layer 28 is preferably 1 μm to 100 μm, more preferably 3 μm to 80 μm, and still more preferably 3 μm to 50 μm. If it is in such a range, when the glass resin laminate 1 is attached to an optical element such as a liquid crystal cell to produce an optical laminate, an optical laminate excellent in flexibility and puncture resistance can be obtained.

[0053] [Release film] The release film 29 can be formed of a resin such as polyethylene terephthalate (PET), polyethylene (PE), or polypropylene (PP). The thickness of the release film 29 is preferably 5 μm to 125 μm, more preferably 20 μm to 75 μm, and still more preferably 30 μm to 50 μm. The release film 29 is peeled off at the interface with the adhesive layer 28 before the glass resin laminate 1 is attached to an optical element such as a liquid crystal cell.

[0054] (Manufacturing method of glass resin laminate) Next, regarding the method for manufacturing a glass resin laminate, attention will be paid to the step of sandwiching a glass film 10 and a resin film 20 between a roll for pressing the resin film 20 and a roll for pressing the glass film 10, and bonding them via an adhesive layer 21 for explanation.

[0055] FIG. 2 is a diagram for explaining the step of laminating a glass film on a resin film. In FIG. 2, the resin film 20 is suspended by rolls 110, 120, and 130 and conveyed in the direction of the arrow. The resin film 20 is conveyed, for example, by a roll-to-roll method. A roll 140 is disposed at a position facing the roll 110 in the vertical direction.

[0056] In addition, although three rolls are illustrated for conveying the resin film 20 in FIG. 2, this is an example, and the number of rolls can be appropriately determined according to the need.

[0057] The glass film 10 is conveyed in the direction of the arrow and laminated on the resin film 20 between the roll 110 and the roll 140. At this time, the roll 140 presses the glass film 10, and the roll 110 presses the resin film 20.

[0058] Thereby, the glass film 10 is laminated on the resin film 20. At this point, the adhesive layer 21 is uncured. The adhesive layer 21 is cured in a curing process (not shown) disposed on the downstream side in the conveying direction (arrow direction) from the rolls 110 and 140, and the glass resin laminate 1 is completed. Note that the thickness of the adhesive layer 21 hardly changes before and after curing.

[0059] Here, problems that may occur when laminating the glass film 10 on the resin film 20 using a conventional method will be described. FIG. 3 is a diagram for explaining conventional problems when laminating a glass film on a resin film.

[0060] In FIG. 3, instead of the roll 110 shown in FIG. 2, a roll 110X is used. The roll 110X is made of iron. That is, in the roll 110X, the portion corresponding to the surface layer of the roll 110 is formed of iron.

[0061] As shown in FIG. 3, foreign matter F may adhere to the roll 110X. In this case, when the glass film 10 is laminated on the resin film 20, the roll 110X side of the resin film 20 comes into contact with the foreign matter F. At this time, the highly rigid iron roll 110X and the glass film 10 hardly deform, and the resin film 20 with low rigidity mainly deforms. Therefore, unevenness corresponding to the shape of the foreign matter F occurs on the side of the resin film 20 that contacts the glass film 10, and air may enter the concave portion, resulting in the occurrence of bubble defects B.

[0062] The bubble defect B is large enough to be visible to the human eye. Therefore, when the glass resin laminate 1 is used in products such as display devices, only a certain number or less are allowed, and it is preferably zero if possible. Therefore, in order to solve such conventional problems, in this embodiment, measures are taken to suppress the occurrence of the bubble defect B. This will be described with reference to FIGS. 4 and 5.

[0063] FIG. 4 is a diagram for explaining a method of suppressing the occurrence of bubble defects, and shows an enlarged view of the vicinity of the rolls 110 and 140 in FIG. 2. As described with reference to FIG. 3, conventionally, an iron roll was often used. However, in this embodiment, the surface layer of the roll 110 is formed of a material having a lower elastic modulus than iron. The surface layer refers to a region from the surface of the roll 110 to about 1 mm inward in the central direction.

[0064] The material having a lower elastic modulus than iron is not particularly limited. For example, resins such as polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP), and rubbers such as silicone rubber, urethane rubber, and nitrile rubber can be mentioned. Among these, silicone rubber having excellent flexibility is particularly preferable.

[0065] FIG. 5 is an enlarged view of part A in FIG. 4. In FIG. 5, due to the presence of the foreign object F, the surface layers of the resin film 20 and the roll 110 are deformed.

[0066] Here, let the length of the foreign object F before compression in the direction perpendicular to the surface of the resin film 20 be t, and taking into account the compression when the glass film 10 is laminated on the resin film 20, the length of the foreign object F after compression is Δl = √t. This is based on the findings from the inventors' experience.

[0067] Also, among the length Δl of the foreign object F after compression, let the length on the resin film 20 side be Δlp and the length on the roll 110 side be Δlr. At this time, if the elastic modulus of the resin film 20 is Ep and the elastic modulus of the surface layer of the roll 110 is Er, then from the relationship between the strains on both sides of the foreign object F and the elastic modulus, the following formula (1) is derived.

[0068]

Equation

[0069]

Equation

[0070] Here, assuming that polyethylene terephthalate (PET) is used as the material for the surface layer of roll 110, its elastic modulus is about 5 GPa. Since the elastic modulus of resin film 20 is also about 5 GPa, when Δlp is obtained using equations (1) and (2), Δlp = 5 μm. That is, foreign object F penetrates into resin film 20 by about 5 μm. At this time, since the uncured adhesive layer 21 has high flexibility, if the thickness of the adhesive layer 21 is 5 μm or more, the adhesive layer 21 absorbs Δlp, and as shown in Fig. 4, the side of resin film 20 in contact with glass film 10 does not deform. That is, the bubble defect B as shown in Fig. 3 does not occur.

[0071] Also, assuming that silicone rubber is used as the material for the surface layer of roll 110, its elastic modulus is about 1.5 MPa. Since the elastic modulus of resin film 20 is about 5 GPa, when Δlp is obtained using equations (1) and (2), Δlp = 3.0×10 -3 μm. That is, foreign object F penetrates into resin film 20 by about 3.0×10 -3 μm (almost no penetration). At this time, since resin film 20 hardly deforms, even when the thickness of the adhesive layer 21 is extremely thin, the side of resin film 20 in contact with glass film 10 does not deform. That is, the bubble defect B as shown in Fig. 3 does not occur.

[0072] That is, when glass film 10 is laminated on resin film 20 having an adhesive layer 21 of 5 μm or less and an elastic modulus of about 5 GPa, it is preferable to form the surface layer of roll 110 with a material having a relatively low elastic modulus such as polyethylene terephthalate (PET) or silicone rubber. Thereby, even when foreign object F adheres to the surface of roll 110, deformation of resin film 20 can be suppressed, and generation of bubble defect B can be suppressed.

[0073] Thus, if the elastic modulus of the surface layer of the roll 110 is low, the contribution of the deformation caused by the foreign matter F to the resin film 20 is reduced, so that the generation of the bubble defect B can be suppressed. Also, if the deformation of the resin film 20 caused by the foreign matter F is reduced, the degree to which the adhesive layer 21 contributes to the relaxation of the deformation can be reduced, so that a thinner adhesive layer 21 can be used.

[0074] More generally speaking, in the manufacturing process of the glass resin laminate, when the elastic modulus of the surface layer of the roll 110 is P1 and the elastic modulus of the resin film 20 is P2, the ratio P1 / P2 of the elastic modulus P1 to the elastic modulus P2 is 3×10 -3 ≦P1 / P2≦1.0, it can be said that the material of the surface layer of the roll 110 may be selected so as to satisfy this condition. However, in the roll 110, the portion other than the surface layer may be formed of the same material as the surface layer.

[0075] The above requirements are more effective when the adhesive layer bonding the glass film and the resin film is thinner. For example, the effect is remarkable when the thickness of the adhesive layer is 0.1 μm or more and 5 μm or less. In other words, when an adhesive layer thicker than 10 μm is used, the generation of the bubble defect B may be suppressed even if the above requirements are not satisfied. However, increasing the thickness of the adhesive layer causes problems such as a decrease in the transportability of the resin film and an increase in the curing time of the adhesive layer. Therefore, it is not preferable to make the adhesive layer 10 μm or more.

[0076] In the above discussion, the roll 140 has not been touched upon. However, regarding the roll 140, since the rigid glass film 10 hardly deforms, it is considered that the material of the surface layer of the roll 140 does not affect the above discussion. Therefore, the material of the surface layer of the roll 140 may be iron, resin, rubber, or others.

[0077] Hereinafter, the lamination of the resin film and the glass film will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples at all.

[0078] [Example 1] In Example 1, a resin film with an elastic modulus of 5 GPa and an adhesive layer with a thickness of 2 μm was prepared, and a glass film was laminated on the resin film between rolls facing each other vertically. Then, the adhesive layer was cured to produce a glass resin laminate A. A polyethylene terephthalate (PET) with an elastic modulus of 5 GPa was used for the surface layer of the roll in contact with the resin film.

[0079] [Example 2] In Example 2, a glass resin laminate B was produced in the same manner as in Example 1, except that the thickness of the adhesive layer was 5 μm.

[0080] [Example 3] In Example 3, a glass resin laminate C was produced in the same manner as in Example 1, except that the thickness of the adhesive layer was 10 μm.

[0081] [Comparative Example 1] In Comparative Example 1, a resin film with an elastic modulus of 5 GPa and an adhesive layer with a thickness of 2 μm was prepared, and a glass film was laminated on the resin film between rolls facing each other vertically. Then, the adhesive layer was cured to produce a glass resin laminate D. Iron with an elastic modulus of 73 GPa was used for the surface layer of the roll in contact with the resin film.

[0082] [Comparative Example 2] In Comparative Example 2, a glass resin laminate E was produced in the same manner as in Comparative Example 1, except that the thickness of the adhesive layer was 5 μm.

[0083] [Comparative Example 3] In Comparative Example 3, a glass resin laminate F was produced in the same manner as in Comparative Example 1, except that the thickness of the adhesive layer was 10 μm.

[0084] [Evaluation] For each of the glass resin laminates A to F produced in Examples 1 to 3 and Comparative Examples 1 to 3, the number of bubble defects was visually checked. The results are shown in Tables 1 and 2. The judgment was ○ (qualified) if the number of bubble defects [ / m 2 was 50 or less, and × (unqualified) if it was more than 50.

[0085] [Table 1]

[0086] [Table 2] As shown in Table 1, when the surface layer of the roll in contact with the resin film was formed of polyethylene terephthalate (PET), the number of bubble defects was within the allowable range regardless of whether the thickness of the adhesive layer was 2 μm, 5 μm, or 10 μm. In particular, when the thickness of the adhesive layer was 5 μm or more, the number of bubble defects became zero, which was a very favorable result.

[0087] From the above-mentioned examination results, it is expected that if the surface layer of the roll in contact with the resin film is formed of silicone rubber, the number of bubble defects can be made almost zero even when the thickness of the adhesive layer is 2 μm or less.

[0088] On the other hand, as shown in Table 2, when iron was used for the surface layer of the roll in contact with the resin film, the number of bubble defects was zero when the thickness of the adhesive layer was 10 μm, but when the thicknesses of the adhesive layer were 2 μm and 5 μm, the number of bubble defects exceeded the allowable range. That is, when using a thin adhesive layer with a thickness of 5 μm or less, it can be said that it is necessary to use polyethylene terephthalate (PET) or a material with a lower elastic modulus (such as silicone rubber) for the surface layer of the roll in contact with the resin film.

[0089] Thus, from the results of this example and the comparative example, in the manufacturing process of the glass resin laminate, when the elastic modulus of the surface layer of the roll in contact with the resin film is P1 and the elastic modulus of the resin film is P2, when the ratio P1 / P2 of the elastic modulus P1 to the elastic modulus P2 satisfies 3×10 -3 ≦P1 / P2≦1.0, it was confirmed that by selecting the material of the surface layer of the roll in contact with the resin film, the occurrence of bubble defects can be suppressed.

[0090] Furthermore, it was confirmed that the above requirements are more effective when the adhesive layer bonding the glass film and the resin film is thinner, and the effect is remarkable when the thickness of the adhesive layer is 5 μm or less.

[0091] In addition, the above has been described by taking the resin film having a polarizing plate as an example. However, the above requirements are effective for a method for manufacturing a glass resin laminate having a step of bonding a glass film and a resin film via an adhesive layer using two opposing rolls, and are not limited to a resin film having a polarizing plate. Examples other than the resin film having a polarizing plate include, for example, a PET film, a PEN film, and the like.

[0092] As described above in detail about the preferred embodiments etc., it is not limited to the above-described embodiments etc., and various modifications and substitutions can be made to the above-described embodiments etc. without departing from the scope described in the claims.

[0093] This international application claims priority based on Japanese Patent Application No. 2019-066162 filed on March 29, 2019, and incorporates the entire contents of Japanese Patent Application No. 2019-066162 into this international application.

Explanation of Signs

[0094] 1 Glass resin laminate 10 Glass film 20 Resin film 21 Adhesive layer 22 Polarizing plate 28 Adhesive layer 29 Release film 110, 120, 130, 140 Rolls 221 Polarizer 222 First protective film 223 Second protective film

Claims

[Claim 1] A method for producing a glass resin laminate, comprising: sandwiching a glass film and a resin film between a first roll that presses the resin film and a second roll that is disposed opposite the first roll and presses the glass film, and bonding the glass film and the resin film together via an adhesive layer, a surface layer of the first roll is formed of a resin material having a lower elastic modulus than that of iron, the resin material is polyethylene terephthalate, polyethylene, or polypropylene; When the elastic modulus of the surface layer of the first roll is P1 and the elastic modulus of the resin film is P2, the ratio P1 / P2 of the elastic modulus P1 to the elastic modulus P2 is 3×10 －３ ≦P1 / P2≦1.0 is satisfied.

Images