JP2006192658A - Crack preventing film of glass plate, optical film and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the crack of the glass substrate or the like of a display such as LCD or the like, to reduce an increase in the thickness of the display or the like and to prevent even the mixing with dust or the lowering of visibility. <P>SOLUTION: This crack preventing film of the glass plate comprises a base material layer and an adhesive layer. The base material layer is characterized in that its thickness is 50 μm-below 1 mm, its tensile elastic modulus is 1.0×10<SP>9</SP>-below 5.0×10<SP>10</SP>Pa and the adhesive layer is characterized in that its thickness is 10 μm-below 1 mm and its tensile elastic modulus is 1.0×10<SP>6</SP>-below 5.0×10<SP>9</SP>Pa. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a glass plate breakage prevention film, an optical film provided with the same, and a display provided with these glass plate breakage prevention film or optical film.

  Examples of various displays used for cellular phones include liquid crystal displays (LCDs). Conventionally, these display surfaces are made of acrylic from the viewpoint of preventing breakage of the glass substrate that is a component of the display. A cover is provided.

  However, if an acrylic cover is provided on the display surface, the thickness of the display will increase, and there will be a slight air layer between the display surface and the acrylic cover. This causes problems such as deterioration of sex.

  The present invention has been made in view of the above-described problems of the prior art, and is intended to prevent cracking of a glass substrate of a display such as an LCD and to reduce the increase in thickness of the display as much as possible. In addition, it is an object to prevent dust from being mixed and the visibility from being deteriorated.

In order to solve the above problems, the present invention includes a base material layer and an adhesive layer, the base material layer has a thickness of 50 μm or more and less than 1 mm, and a tensile elastic modulus of 1.0 × 10 ⁹ Pa or more and 5. 0 × 10 ¹⁰ Pa or less, the adhesive layer has a thickness of 10 μm or more and less than 1 mm, and a tensile elastic modulus of 1.0 × 10 ⁶ Pa or more and less than 5.0 × 10 ⁹ Pa. Provided is a glass plate cracking prevention film.

  In addition, the present invention provides an optical film with a function of preventing glass plate breakage, wherein the glass plate breakage preventing film and an optical film are laminated.

  Furthermore, the present invention provides a display comprising the above-described glass plate breakage prevention film or the above-described optical film with a glass plate breakage prevention function.

  According to the glass plate crack prevention film, the optical film and the display according to the present invention, it is possible to prevent the glass substrate from cracking without increasing the thickness of the display so much, and to adhere the display surface and the film to each other. It is also possible to prevent the contamination and the deterioration of visibility.

Hereinafter, an exemplary embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing one embodiment of a glass sheet crack preventing film according to the present invention. The glass plate crack prevention film 1 according to the present embodiment includes a base material layer 2 and an adhesive layer 3.

  The base material layer 2 has a thickness of 50 μm or more and less than 1 mm, preferably less than 800 μm, more preferably less than 500 μm. If the thickness is less than 50 μm, a sufficient crack preventing function for the glass substrate cannot be obtained, and conversely if the thickness exceeds 1 mm, it cannot be reduced in thickness and weight.

The base material layer 2 has a tensile modulus of 1.0 × 10 ⁹ Pa or more and less than 5.0 × 10 ¹⁰ Pa, preferably less than 4.0 × 10 ¹⁰ Pa, more preferably 3. It shall be less than 0 × 10 ¹⁰ Pa.
If the tensile elastic modulus of the base material layer 2 is less than 1.0 × 10 ⁹ Pa, it becomes difficult to obtain a glass crack preventing action. Conversely, if the tensile elastic modulus is 5.0 × 10 ¹⁰ Pa or more, the base material There is a possibility that the material itself becomes brittle and the base material is likely to crack.

  In the present invention, the tensile elastic modulus (hereinafter sometimes simply referred to as elastic modulus) refers to the tensile elastic modulus defined in JIS K7161 “Plastics—Testing Method for Tensile Properties”, for example, viscoelasticity. Using a spectrometer (model “ARES”, manufactured by Rheometric Co., Ltd.), it is measured at 25 ° C. by 0.2% tension.

  Examples of the resin component constituting the base layer 2 include polyester resins, polyethylene resins, polystyrene resins, polycarbonate resins, polyamide resins, polyacetal resins, polyphenylene sulfide resins, and other thermoplastic resins, phenol resins, epoxy resins, vinyl ester resins. A curable resin such as a polyimide resin, a melamine resin, a urea resin, or an acrylic resin can be used alone or in combination. Among these resins, a curable resin that is in a liquid state at room temperature in a state before curing, particularly an epoxy resin is preferable. Moreover, this base material layer 2 can also be comprised as a laminated body formed by laminating | stacking two or more layers which consist of these resin.

  As the epoxy resin, conventionally known epoxy resins can be used, for example, bisphenol types such as bisphenol A type, bisphenol F type, bisphenol S type and their water additives; novolak types such as phenol novolak type and cresol novolak type. Nitrogen-containing ring type such as triglycidyl isocyanurate type and hindantin type; alicyclic type; aliphatic type; naphthalene type; low water absorption type such as glycidyl ether type and biphenyl type; dicyclo type such as dicyclopentadiene type; Ester type; ether ester type; and modified types thereof. Among these epoxy resins, bisphenol A type epoxy resin, alicyclic epoxy resin, triglycidyl isocyanurate type epoxy resin, and dicyclopentadiene type epoxy resin are preferable from the viewpoint of discoloration prevention property and the like. These epoxy resins may be used alone or in combination of two or more. However, a combination of the dicyclopentadiene type epoxy resin and the alicyclic epoxy resin is preferable from the viewpoint that heat resistance, toughness, and low birefringence are exhibited in an excellent balance.

  Examples of the bisphenol A type epoxy resin include those represented by the following chemical formula (1). In the formula, n is, for example, 0-2.

  Examples of the alicyclic epoxy resin include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate represented by the following chemical formula (2) and those represented by the following chemical formula (3). In the following chemical formula (3), n is an integer of 1 to 20, and R is an alkyl group.

  Examples of the dicyclopentadiene type epoxy resin (epoxy resin having a dicyclopentadiene skeleton) include epoxy resins represented by the following chemical formulas (4) and (5). In addition, in following Chemical formula (5), n is an integer of 1-3.

  Among the epoxy resins described above, the epoxy resin represented by the chemical formula (4) or (5) is particularly preferable. This is because if these resins are used, the thickness direction retardation of the film can be controlled to a small value. Thus, when the thickness direction retardation is small, when the film is used in a liquid crystal display device, light leakage from an oblique direction in black display is suppressed and display characteristics are further improved.

The epoxy resin preferably has an epoxy equivalent of 100 to 1000 (g / eq) and a softening point of 120 degrees or less, and more preferably an epoxy resin, for example, to improve the flexibility and strength of the resin sheet to be formed. The equivalent is 150 to 500 (g / eq) and the softening point is 80 ° C. or lower. Moreover, it is preferable that the said epoxy resin becomes a liquid in the state which is normal temperature (for example, 5-35 degreeC), and does not contain a solvent.
In addition, when forming the base material layer, a two-component mixed epoxy resin that exhibits a liquid state without containing a solvent at a temperature equal to or lower than the temperature at the time of coating, particularly at a normal temperature is preferable because it is excellent in developability and coating properties. .

In addition to the resin, various additives may be blended in the resin liquid that forms the cured resin as necessary.
Examples of the additive include a curing agent, a curing accelerator, an anti-aging agent, a modifier, a surfactant, a dye, a pigment, a discoloration inhibitor, an ultraviolet absorber, and a photoinitiator.
The ratio of the resin component in the resin liquid is usually 30 to 100% by weight, preferably 40 to 90% by weight, and more preferably 40 to 80% by weight. In the present specification, when the resin liquid contains a solvent, the weight ratio of each component in the resin liquid means the weight ratio when the total weight is the weight excluding the solvent.

  The curing agent is not particularly limited, and examples thereof include organic acid compounds such as tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, and methylhexahydrophthalic acid, ethylenediamine, propylenediamine, diethylenetriamine, and triethylenetetramine. And amine compounds such as these amine adducts, metaphenylenediamine, diaminediphenylmethane, and diaminodiphenylsulfonic acid. Any one of these curing agents may be used, or two or more thereof may be used in combination.

  In addition to the curing agent as described above, for example, amide compounds such as dicyandiamide and polyamide, hydrazide compounds such as dihydragit, methylimidazole, 2-ethyl-4-methylimidazole, ethylimidazole, isopropylimidazole, Imidazole compounds such as 2,4-dimethylimidazole, phenylimidazole, undecylimidazole, heptadecylimidazole, 2-phenyl-4-methylimidazole, methylimidazoline, 2-ethyl-4-methylimidazoline, ethylimidazoline, isopropylimidazoline, Imidazoline compounds such as 2,4-dimethylimidazoline, phenylimidazoline, undecylimidazoline, heptadecylimidazoline, 2-phenyl-4-methylimidazoline; Nord-based compounds, urea-based compounds, also include polysulfide-based compounds and the like.

  Furthermore, acid anhydride compounds can be used as the curing agent. Such acid anhydride compounds are preferable in terms of, for example, discoloration prevention. Specific examples of acid anhydride compounds include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, nadic acid anhydride, glutaric anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, Hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl nadic anhydride, dodecenyl succinic anhydride, dichlorosuccinic anhydride, benzophenone tetracarboxylic acid An anhydride, a chlorendic acid anhydride, etc. are mentioned. Among these acid anhydride compounds, those having a colorless or pale yellow color and having a molecular weight of about 140 to about 200 are preferable. For example, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride Products, methyl hexahydrophthalic anhydride, methyl nadic acid anhydride, and the like.

  When an epoxy resin is used as the resin component of the resin liquid and an anhydride type curing agent is used as the curing agent, the blending ratio of the epoxy resin and the curing agent is not particularly limited, but the epoxy group of the epoxy resin is not limited. It is preferable to mix | blend so that an acid anhydride equivalent may be 0.5-1.5 equivalent with respect to 1 equivalent, More preferably, you may be 0.7-1.2 equivalent. If the blending amount of the acid anhydride is 0.5 or more, the hue after curing is further excellent, and if it is 1.5 equivalents or less, sufficient moisture resistance can be maintained. In addition, when using another hardening | curing agent, or when using together 2 or more types of hardening | curing agents, it can mix | blend according to the above ratios, for example.

  The curing accelerator is not particularly limited, and examples thereof include tertiary amines, imidazoles, quaternary ammonium salts, quaternary phosphonium salts, organometallic salts, phosphorus compounds, urea compounds, and the like. Of these, tertiary amines, imidazoles, and quaternary phosphonium salts are particularly preferable. These curing accelerators may be used alone or in combination of two or more.

  The blending ratio of the curing accelerator in the resin liquid is not particularly limited, and is appropriately determined according to the type of resin component used. For example, when using an epoxy resin, it is preferable that a hardening accelerator is 0.05-7.0 weight part with respect to 100 weight part of epoxy resins, for example, and 0.2-3.0 weight part is more preferable. . If the blending ratio of the curing accelerator is 0.05 parts by weight or more, a sufficient curing acceleration effect can be obtained, and if it is 7.0 parts by weight or less, the hue after curing is excellent.

Although it does not restrict | limit especially as said anti-aging agent, For example, conventionally well-known things, such as a phenol type compound, an amine type compound, an organic sulfur type compound, a phosphine type compound, can be used.
Although it does not restrict | limit especially as said modifier | denaturant, For example, conventionally well-known things, such as glycols, silicones, alcohol, can be used.

  As said surfactant, various surfactants, such as silicone type, an acryl type, a fluorine type, can be used, for example, Among these, a silicone type is preferable. These surfactants are added, for example, to smooth the sheet surface when forming a resin sheet by curing the resin liquid in contact with air.

  In addition, the base material layer 2 may be formed by integrally impregnating a resin material and a reinforcing material by impregnating the resin material with a reinforcing material such as glass fiber. In this case, for example, a base material layer is formed by allowing a resin solution to exist between glass fibers and curing by a known method such as a casting method, a casting method, an impregnation method, and a coating method. can do.

As the glass fiber, any of a long fiber and a short fiber can be used. This glass fiber is contained in the cured resin layer in a state in which short fibers are mixed in the cured resin layer, a state in which short fibers or long fibers are made into a nonwoven fabric, or a state of glass cloth (woven fabric). May be. However, a glass cloth state is preferable from the viewpoint of strength.
The glass cloth is, for example, a yarn obtained by twisting about 100 to 800 long fibers (filaments) having a circular or elliptical cross section and a longest diameter of about 3 to 10 μm as warp and weft. Woven by interlacing yarns.
Examples of the weaving method include plain weave, twill weave, and satin weave.
The thickness of the glass cloth is usually 10 to 500 μm, preferably 15 to 350 μm, at the thickest part.

  As the material of the glass fiber, soda glass, borosilicate glass, alkali-free glass or the like is used. However, alkali-free glass is preferred because alkali components in the glass may adversely affect the TFT and the like.

Moreover, it is preferable that the elasticity modulus of glass fiber is 25 times or more of the resin cured material which comprises a base material layer, and it is preferable that it is 500 times or less. The specific value of the elastic modulus is usually 5 to 500 GPa, preferably 10 to 200 GPa. Within such a range, the cured resin layer can have a sufficiently low thermal expansion coefficient and excellent mechanical strength. This reduces stress birefringence caused by shrinkage when the resin liquid is cured, cooling shrinkage, and the like. For example, when applied to a liquid crystal display device, light leakage from an oblique direction in a black display state is extremely small. Can be.
In addition, the glass fiber of such a range can be obtained by selecting suitably the thing of a desired elasticity modulus from conventionally well-known glass fiber.

As a specific method for forming the base material layer, the following various methods can be employed.
For example, first, by placing a glass cloth on a flat plate mold, applying a resin liquid on the glass cloth, and then applying a reduced pressure condition, the glass cloth is impregnated with the resin liquid and subjected to heat treatment or UV irradiation. A method of curing a resin liquid and forming a cured resin layer in which a glass cloth is embedded can be employed.
Also, a method of forming a cured resin layer in which the glass cloth is embedded by immersing the glass cloth in the resin liquid by impregnation under normal pressure conditions and curing the resin liquid in that state can be employed.
Furthermore, it is also possible to employ a method in which a glass cloth is disposed on an endless belt or a substrate and impregnated or coated with a resin liquid. In addition, you may perform hardening processing, such as a heat processing and a light irradiation process, for example with respect to the apply | coated resin liquid as needed.

When an epoxy resin containing a dicyclopentadiene type epoxy resin is used as the resin component of the resin liquid, although not particularly limited, for example, it is preferable to perform a heat treatment at 100 to 200 ° C. for 10 minutes to 5 hours.
When using an epoxy resin as the resin component of the resin liquid, the epoxy resin may be dispersed or dissolved in a solvent to prepare an epoxy resin liquid, which may be used. Although it does not restrict | limit especially as a solvent, For example, methyl ethyl ketone, acetone, methyl isobutyl ketone, toluene, xylene, ethyl acetate etc. can be used. In addition, you may add suitably other resin as mentioned above and various additives to the liquid epoxy resin liquid which does not contain a solvent, or the epoxy resin liquid which dissolved the epoxy resin in the solvent.

In the present invention, the ratio of the cured resin (part of the cured resin layer excluding glass fibers) in the base material layer is, for example, 20 to 80% by weight, preferably 25 to 75% by weight, More preferably, it is 30 to 70% by weight. The ratio of glass fiber can use what is 20 to 80 weight%, for example, Preferably it is 25 to 75 weight%, More preferably, it is 30 to 70 weight%.
Such a base material layer can be obtained by adjusting the weight ratio of the resin liquid in the total weight of the resin liquid and glass fiber before curing to the above range. When the resin liquid contains a solvent, the weight of the resin liquid does not include the weight of the solvent.

Examples of the method for adjusting the elastic modulus of the cured resin product include a method of keeping the crosslinking density low when the resin solution before curing is crosslinked, a method of adding a plasticizer as one component of the resin solution before curing, and the like. It is done.
Examples of a method for keeping the crosslinking density low include a method of adding a reaction diluent as one component of the resin liquid before curing.
Furthermore, in the case of forming a resin cured product by thermosetting, a method of lowering the curing temperature, a method of shortening the heating time, a method of reducing the amount of the curing accelerator, etc. can be employed alone or in combination.
In addition, in the case of curing the resin by ultraviolet curing, electron beam curing, etc., a method of lowering the concentration of the initiator or sensitizer, a method of reducing the irradiated ultraviolet light or electron beam, etc. alone or in combination Can be adopted.
In these methods, the elastic modulus of the cured resin can be set to a desired value by appropriately adjusting the addition amount, curing temperature, irradiation time, or the like.

  When the substrate layer 2 is composed of the above glass fiber and resin cured product, the absolute value of the difference in average refractive index between the resin cured product and the glass fiber is 0 to 0.01. It is preferably 0 to 0.008, more preferably 0 to 0.006. When the absolute value is 0.01 or less, the interface scattering between the glass fiber and the cured resin can be sufficiently suppressed, the haze of the resin sheet is reduced, and the transparency inherent in the cured resin layer is sufficiently maintained. Because it can.

In addition, a refractive index difference can be adjusted by adjusting the compounding ratio of each component in a resin liquid, for example.
Here, the average refractive index of the glass fiber and the cured resin product is 25 ° C. and 589 nm using an Abbe refractometer, respectively, using a glass fiber sheet and a separately molded resin cured sheet. Can be measured.
The average refractive index means an average value of nx, ny, and nz. nx, ny, and nz mean the refractive indexes in the X-axis, Y-axis, and Z-axis directions in each sheet, respectively. The X-axis direction means an axial direction showing the maximum refractive index in the plane of each sheet, and the Y-axis direction means an axial direction perpendicular to the X-axis in the plane, and the Z-axis direction. Means an axial direction perpendicular to the surface.
Moreover, as an average refractive index of the said resin cured material and glass fiber, 0.01 or less is respectively preferable.
Examples of the method of setting the average refractive index of the cured resin to 0.01 or less include a method of adjusting the blending amount of various additives (for example, a curing agent) blended in the resin liquid.

Furthermore, the substrate layer preferably has an in-plane retardation of 2 nm or less, more preferably 0 to 1 nm, and particularly preferably 0 to 0.8 nm.
If the in-plane retardation is 2 nm or less, when used as a liquid crystal cell substrate, an organic EL device substrate, or the like, the contrast of the image display device, particularly the contrast in the perspective direction, is further improved and exhibits excellent display quality. Become.

  The thickness direction retardation of the base material layer is preferably 40 nm or less, more preferably 0 to 20 nm, and particularly preferably 0 to 10 nm. When the thickness direction retardation is 40 nm or less, when used in an image display device as described above, light leakage from the perspective direction is more sufficiently suppressed, and the contrast in the perspective direction is further improved, which is more excellent. Display quality is indicated. When the thickness direction retardation is set to 40 nm or less, particularly 20 nm or less, it is particularly preferable to use an epoxy resin represented by the above formula (4) or (5) as the resin component.

The in-plane retardation (Δnd) and the thickness direction retardation (Rth) are each expressed by the following equations. In the following formula, nx, ny, and nz represent the refractive indexes of the base layer in the X-axis, Y-axis, and Z-axis directions, respectively, and d represents the thickness of the base layer. Here, the X-axis direction means an axial direction showing the maximum refractive index in the plane of the base material layer, and the Y-axis direction means an axial direction perpendicular to the X-axis in the plane. The Z-axis direction means an axial direction perpendicular to the surface.
Δnd = (nx−ny) · d
Rth = (nx−nz) · d

  On the other hand, the adhesive layer 3 has a thickness of 10 μm or more and less than 1 mm, preferably less than 900 μm, more preferably less than 800 μm. If the thickness is less than 10 μm, a sufficient crack preventing function for the glass substrate cannot be obtained, and conversely if the thickness exceeds 1 mm, it cannot be reduced in thickness and weight.

The adhesive layer 3 has a tensile modulus of 1.0 × 10 ⁶ Pa or more and less than 5.0 × 10 ⁹ Pa, preferably less than 4.5 × 10 ⁹ , more preferably 4.0 ×. The pressure is less than 10 ⁹ Pa.
If the tensile elastic modulus of the adhesive layer 3 is less than 1.0 × 10 ⁶ Pa, it becomes difficult to obtain a glass crack preventing action, and conversely if the tensile elastic modulus is 5.0 × 10 ⁹ Pa or more, the adhesive layer becomes It may become brittle and cracks are likely to occur.

  As such an adhesive layer 3, at least one kind of adhesive selected from an epoxy adhesive, a silicone adhesive, a urethane adhesive, an acrylic adhesive, a urea adhesive, an olefin adhesive, and a melamine adhesive is used. An epoxy-based adhesive and a silicone-based adhesive can be preferably used from the viewpoint that adhesion to the base material layer and appropriate viscoelasticity can be obtained.

  As the epoxy adhesive, either a thermosetting type or an ultraviolet curable type can be used. However, since the adhesiveness with the base material layer is good and the elastic modulus is particularly suitable, the thermosetting type is used. preferable.

The silicone-based adhesive is not particularly limited, but a more effective glass plate cracking prevention function can be obtained, so that the tensile modulus after curing is 1.4 × 10 ^{6 to} 2.0 × 10 ^{6. A} silicone-based adhesive with ⁶ Pa is preferred.

  Next, an embodiment of an optical film with a glass plate crack preventing function according to the present invention will be described. FIG. 2 is a schematic cross-sectional view showing an embodiment of an optical film with a glass plate crack preventing function according to the present invention. An optical film 5 with a glass plate crack preventing function according to this embodiment is formed by laminating a glass plate crack preventing film 1 and an optical film 4.

  The glass plate crack prevention film 1 includes the base material layer 2 and the adhesive layer 3 as described above, and the description thereof is omitted here.

  On the other hand, as the optical film 4, any known optical film having various functions such as polarization, phase difference compensation, viewing angle expansion, luminance improvement, surface reflection prevention, and antiglare can be used.

  The glass plate crack preventing film and the optical film with glass plate crack preventing function of the present invention can be used in various displays such as liquid crystal display devices and EL display devices, solar cells, and the like.

For example, a liquid crystal display device generally includes a liquid crystal cell substrate that holds liquid crystal on both the viewing side and the non-viewing side, a polarizing plate laminated on the liquid crystal cell substrate, and a reflector or backlight. The glass plate crack preventing film and the optical film with a glass plate crack preventing function of the present invention are used for preventing cracking of the liquid crystal cell substrate on the viewing side or the non-viewing side in such a liquid crystal display device. be able to.
The EL display device generally includes a transparent substrate (EL display substrate), a transparent electrode on the back side of the transparent substrate, an organic light emitting layer including a light emitter (organic electroluminescent light emitter), and a metal electrode in order. The glass plate breakage prevention film and the optical film with a glass plate breakage prevention function of the present invention can be used for preventing cracking of a transparent substrate in such an EL display device.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In each example, parts and% are based on weight.

Example 1
50 parts of 3,4-epoxycyclohexylmethyl-3,4 epoxycyclohexanecarboxylate represented by the chemical formula (2) as a resin component and a dicyclopentadiene type epoxy resin (epoxy equivalent 190) 50 represented by the following chemical formula (6) Part and 0.95 part of tetra-n-butylphosphonium o, o-diethylphosphodithioate represented by the following chemical formula (7) as a curing agent were stirred and mixed to prepare an epoxy resin composition (resin liquid).
Next, a glass cloth (trade name “WLT116F”, manufactured by Nitto Boshoku Co., Ltd.) was impregnated with the epoxy resin composition, and left under reduced pressure (200 Pa) for 10 minutes.
Next, a glass plate was prepared by dissolving 17 parts of urethane acrylate represented by the following chemical formula (8) and 5 parts of a photoinitiator (trade name “Irgacure 184”, manufactured by Ciba Specialty Chemicals) in 100 parts of toluene. It was coated on the top with a wire barcode, air-dried, and then cured using a UV curing device. Curing conditions were 200 mJ / cm ² and 1 minute using a high-pressure mercury lamp. As a result, a hard coat layer having a thickness of 2 μm was formed. Subsequently, the two hard coat layers prepared by the above procedure were bonded to both surfaces of the glass cloth impregnated with the epoxy resin composition, and this was heated at 120 ° C. for 1 hour to obtain the epoxy resin composition. After being cured, it was peeled off from the glass plate to obtain a base layer (hard coat layer / epoxy resin layer with glass cloth / hard coat layer) having a thickness of 100 μm. The tensile modulus of the base material layer was 1.7 × 10 ¹⁰ Pa.

Furthermore, the main agent (trade name “Epocure” 20-8132-032, manufactured by Buehler), which is an epoxy adhesive, and the curing agent (trade name “Epocure” 20-8132-008, manufactured by Buehler) are weighted. What was mixed in a ratio of 5: 1 was applied onto the base material layer to form an adhesive layer. Then, a soda glass plate (50 mm × 50 mm, thickness 1 mm) is placed on the adhesive layer, and in this state, it is left to stand at 50 ° C. for 1 hour and then at 23 ° C. for 3 hours, and then cured. The adhesive and base material protruding to the outside are cut off according to the dimensions of the glass plate, and a test sample of 50 mm × 50 mm size (hard coat layer / epoxy base layer with glass cloth / hard coat layer / epoxy adhesive layer / Glass plate). In addition, when it measured after sample preparation, the thickness of the contact bonding layer was 100 micrometers and the tensile elasticity modulus was 3.4 * 10 < ⁹ > Pa.

(Example 2)
The same glass as in Example 1 using a PET film (thickness 250 μm, tensile modulus 1.5 × 10 ⁹ Pa) as the base layer and a silicone adhesive (trade name “Cemedine Super X2”, manufactured by Cemedine) as the adhesive layer. A test sample (PET base material layer / silicone adhesive layer / glass plate) was prepared by covering the plate. The adhesive curing conditions were the same as in Example 1. In addition, the thickness of the contact bonding layer measured after sample preparation was 250 micrometers, and the tensile elasticity modulus was 1.6 * 10 < ⁶ > Pa.

(Comparative Example 1)
The soda glass plate alone of Example 1 was used as a test sample.

(Comparative Example 2)
100 parts of butyl acrylate, 5 parts of acrylic acid, 0.3 part of azobisisobutylnitrile, and 200 parts of ethyl acetate were placed in a four-necked flask and reacted at around 60 ° C. with stirring to obtain a polymer solution. Furthermore, an isocyanate compound (trade name “Coronate L”, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to the polymer solution in an amount of 5 parts with respect to 100 parts of the polymer solid content, and the coating was applied so that the thickness after drying was 25 μm. A test sample (PET base material layer / acrylic adhesive layer / glass plate) was prepared in the same manner as in Example 2 except that the adhesive layer was used. The tensile elastic modulus of the adhesive layer after drying was 2.3 × 10 ⁵ Pa.

(Comparative Example 3)
A test sample (PET base material layer / HBA adhesive layer / glass plate) was prepared in the same manner as in Example 2 except that hydroxybutyl acrylate (HBA) impact resistant paste was used as the adhesive layer. The tensile elastic modulus of the adhesive layer after drying was 4.4 × 10 ⁴ Pa.

(Static strength measurement)
About each test sample of an Example and a comparative example, static strength was measured using the measuring jig as shown in FIG. Specifically, as shown in FIG. 3, the test sample was placed on the measuring jig so that the glass cloth-containing epoxy base layer was on the upper surface, and a 10 mmφ cylindrical portion was pushed in from there. The jig was lowered at a speed of 1 mm / min, the test sample was pushed in at the bottom of the cylindrical portion, and the maximum load immediately before the soda glass was broken was measured. The cylinder was pushed in by using an autograph (model “AG-1”, manufactured by Shimadzu Corporation). The results are shown in Table 1 below.

  As shown in Table 1, the anti-cracking film according to the example of the present invention has a very high static strength compared to the comparative example, although it has a thickness equivalent to that of the comparative example, It can be seen that this is extremely effective for preventing breakage of a glass substrate constituting a display such as an LCD.

The schematic sectional drawing which showed one Embodiment of the glass plate crack prevention film which concerns on this invention. The schematic sectional drawing which showed one Embodiment of the optical film with a glass plate crack prevention function which concerns on this invention. Measurement jig used to measure static strength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass plate crack prevention film 2 Base material layer 3 Adhesion layer 4 Optical film 5 Optical film with a glass plate crack prevention function

Claims (3)

A substrate layer and an adhesive layer, wherein the substrate layer has a thickness of 50 μm or more and less than 1 mm, a tensile elastic modulus of 1.0 × 10 ⁹ Pa or more and less than 5.0 × 10 ¹⁰ Pa, and The adhesive layer has a thickness of 10 μm or more and less than 1 mm, and a tensile modulus of elasticity of 1.0 × 10 ⁶ Pa or more and less than 5.0 × 10 ⁹ Pa.   An optical film with a glass plate crack preventing function, wherein the glass plate crack preventing film according to claim 1 and an optical film are laminated.   A display comprising the glass sheet crack preventing film according to claim 1 or the glass film crack preventing optical film according to claim 2.

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