Glass fiber-reinforced layer

Abstract

The present invention addresses the problem of providing a glass fiber-reinforced layer in which the generation of fold marks when said layer is bent for a certain time is suppressed. In order to solve this problem, provided is a glass fiber-reinforced layer containing glass fibers and a thermoplastic elastomer (E), wherein in the thermoplastic elastomer (E), the loss tangent tanδ has a peak at -20°C or lower and the storage modulus is of 1-1000 MPa.

Description

Glass fiber reinforced layer

[0001] This invention relates to a glass fiber reinforced layer.

[0002] For example, in displays such as liquid crystal displays (LCDs) containing liquid crystal elements and organic electroluminescent displays (OLEDs) containing organic EL elements, glass substrates have traditionally been used. However, in recent years, due to the demand for larger, lighter, and thinner displays, substrates containing resin, for example, are being considered as an alternative to glass substrates. Examples of resin-containing substrates include resin substrates made of resin and substrates containing resin and glass fibers.

[0003] Regarding substrates containing resin and glass fibers, for example, Patent Document 1 describes a resin sheet containing epoxy resin and a glass fiber fabric, with a haze value of 10% or less. Also, although not for display applications, for example, Patent Document 2 describes a transparent non-combustible sheet in which a thermoplastic resin is impregnated into a glass fiber woven fabric.

[0004] Japanese Patent Publication No. 2004-51960 (Corresponding publication: U.S. Patent Application Publication No. 2005 / 0129877) Japanese Patent Publication No. 2017-172085

[0005] Substrates containing resin have properties such as being bendable, but if they are kept bent for a certain period of time, creases may form.

[0006] This invention was made in view of the above circumstances, and aims to provide a glass fiber reinforced layer in which the occurrence of creases when bent for a certain period of time is suppressed.

[0007] The inventors, through diligent research to solve the aforementioned problems, discovered that the problems can be solved by a glass fiber reinforced layer combining glass fibers and a thermoplastic elastomer having a specific peak in its loss tangent tanδ and a specific storage modulus, thereby completing the present invention. The present invention provides the following:

[0008] <1> A glass fiber reinforced layer comprising glass fibers and a thermoplastic elastomer (E), wherein the thermoplastic elastomer (E) has a loss tangent tanδ peaking at -20°C or below, and a storage modulus of 1 MPa or more and 1000 MPa or less. <2> The glass fiber reinforced layer according to <1>, wherein the thermoplastic elastomer (E) comprises one or more selected from the group consisting of aromatic vinyl compound-conjugated diene block copolymer, hydrogenated aromatic vinyl compound-conjugated diene block copolymer, a modified product of aromatic vinyl compound-conjugated diene block copolymer with silicon atom-containing polar groups, and a modified product of hydrogenated aromatic vinyl compound-conjugated diene block copolymer with silicon atom-containing polar groups. <3> The glass fiber reinforced layer according to <1> or <2>, wherein the glass fibers are glass cloth. <4> The glass fiber reinforced layer according to <3>, wherein the ratio of the thickness of the glass fiber reinforced layer to the thickness of the glass cloth is 1 to 5 times. <5> The glass fiber reinforced layer according to any one of <1> to <4>, wherein the absolute value of the difference between the refractive index of the glass fiber and the refractive index of the thermoplastic elastomer (E) is 0.07 or less. <6> The glass fiber reinforced layer according to any one of <1> to <5>, wherein the glass fiber reinforced layer is a constituent layer of a flexible element.

[0009] According to the present invention, it is possible to provide a glass fiber reinforced layer in which the occurrence of creases when bent for a certain period of time is suppressed.

[0010] Figure 1 is a schematic cross-sectional view showing an example of a glass fiber reinforced layer according to one embodiment of the present invention. Figure 2 is a schematic cross-sectional view showing another example of a glass fiber reinforced layer according to one embodiment of the present invention.

[0011] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be modified and implemented as appropriate without departing from the scope of the claims and equivalents of the present invention. The components of the embodiments shown below can be combined as appropriate. For example, any numerical value selected from the group of numerical values ​​listed as lower limits and any numerical value selected from the group of numerical values ​​listed as upper limits can be combined as appropriate. In addition, in the figures, the same components are denoted by the same reference numerals, and their descriptions may be omitted.

[0012] In the following explanation, the term "(meth)acrylic acid" includes "acrylic acid," "methacrylic acid," and combinations thereof. The term "(meth)acrylic acid ester" includes "acrylic acid ester," "methacrylic acid ester," and combinations thereof. The term "(meth)acrylamide" includes "acrylamide," "methacrylamide," and combinations thereof. The term "(meth)acrylonitrile" includes "acrylonitrile," "methacrylonitrile," and combinations thereof.

[0013] A structural unit formed by polymerizing a monomer is called a "monomer unit," with "unit" added after the name of the monomer. For example, a structural unit formed by polymerizing aromatic vinyl compounds is called an "aromatic vinyl compound unit," and a structural unit formed by polymerizing chain-like conjugated diene compounds is called a "chain-like conjugated diene compound unit." However, the term "monomer unit" is not limited to its formation method. Typically, monomer units are repeating units.

[0014] Thermoplastic elastomers are materials that exhibit rubber-like properties at room temperature and become plasticized at high temperatures, allowing for molding and processing. Such thermoplastic elastomers are characterized by their tendency to stretch easily under small loads while being resistant to breakage. Specifically, thermoplastic elastomers typically exhibit a storage modulus of 0.001 to 2 GPa and a tensile elongation (breaking elongation) of 100 to 2000% at 23°C. Tensile elongation can be measured according to JIS K7113. Storage modulus can be measured using commercially available dynamic viscoelasticity measuring devices.

[0015] The thermoplastic elastomer (E) contained in the glass fiber reinforced layer according to one embodiment of the present invention is a material that satisfies specific conditions in addition to the aforementioned conditions with respect to the storage modulus and loss tangent tanδ.

[0016] <1. Overview of the Glass Fiber Reinforced Layer> The glass fiber reinforced layer according to one embodiment of the present invention includes glass fibers and a thermoplastic elastomer (E). The glass fiber reinforced layer may also consist only of glass fibers and a thermoplastic elastomer (E). The thermoplastic elastomer (E) has a loss tangent tanδ that peaks at -20°C or below, and a storage modulus of 1 MPa or more and 1000 MPa or less. Hereinafter, "loss tangent tanδ" may be simply referred to as "tanδ".

[0017] According to the present invention, by including glass fibers and a thermoplastic elastomer (E) in the glass fiber reinforced layer, it is possible to create a glass fiber reinforced layer that is less prone to creasing when bent for a certain period of time.

[0018] The mechanism by which the effects of the present invention are obtained is not clear, but the inventors surmise it to be as follows. However, the technical scope of the present invention is not limited to the mechanism shown below.

[0019] The inventors surmise that when a conventional substrate containing a resin layer is left in a bent state for a certain period of time, the tension generated by the bending causes the resin layer to stretch, resulting in creep and the formation of creases. Furthermore, it is thought that such creases occur because, for example, when a substrate containing a resin layer is curved, the resin layer is significantly stretched on the outside of the curved portion, causing creep. Therefore, the thicker the resin layer, the more likely creases are to occur when curved at the same radius R. Also, the softer and easier the resin layer is to bend, the more likely creases are to occur.

[0020] In contrast, the glass fiber reinforced layer according to the present invention has improved hysteresis and is less prone to creep due to the inclusion of glass fibers. Specifically, because the glass fibers function as a core material, unlike the case with a single layer of glass, it is possible to maintain the flexibility of the glass fiber reinforced layer while suppressing the stretching of the glass fiber reinforced layer. Thermoplastic elastomers (E) with a tanδ peak below -20°C are, in the case of a single layer, stably soft materials in a wide temperature range including low temperatures and room temperature, making them easy to bend, but they have the property of being prone to creep in the region above the temperature where the tanδ peaks. In contrast, the inventors surmise that in the glass fiber reinforced layer according to the present invention, by combining thermoplastic elastomers (E) with glass fibers, the stretching of the glass fiber reinforced layer can be suppressed, thereby suppressing the occurrence of creases due to bending for a certain period of time. Furthermore, the inventors surmise that because the glass fiber reinforced layer includes glass fibers that function like a core material and a soft thermoplastic elastomer (E), it is easy to bend and at the same time suppresses the occurrence of creases due to bending for a certain period of time.

[0021] <2. Morphology of the Glass Fiber Reinforced Layer> Figures 1 and 2 are schematic cross-sectional views showing an example and another example of a glass fiber reinforced layer according to one embodiment of the present invention. As shown in Figures 1 and 2, the glass fiber reinforced layer 10 includes glass fibers 1 and thermoplastic elastomer (E) 2. In the glass fiber reinforced layer 10, it is preferable that the glass fibers 1 constitute a layer. The layer composed of glass fibers 1 may be referred to as the glass fiber layer. When the glass fiber reinforced layer 10 has a glass fiber layer, the glass fiber reinforced layer 10 usually has a layer (X) 11 in which the glass fibers 1 in the glass fiber layer are impregnated with thermoplastic elastomer (E) 2.

[0022] The glass fiber reinforced layer 10 may consist of, for example, a layer (X) 11 containing a glass fiber layer and a thermoplastic elastomer (E) 2, and a layer (Y) that does not contain a glass fiber layer but contains a thermoplastic elastomer (E) 2. In this case, as shown in Figure 1, layer (X) 11 may be located between one main surface S1 and the other main surface S2 of the glass fiber reinforced layer 10 in the thickness direction of the glass fiber reinforced layer 10. Preferably, layer (X) 11 may be located at the center of the glass fiber reinforced layer 10 in the thickness direction. The layer configuration of the glass fiber reinforced layer 10 shown in Figure 1 can also be considered as a layer configuration in which layers (Y) 21 and 22 are provided on the respective main surfaces U1 and 2 of layer (X) 11.

[0023] Furthermore, as shown in Figure 2, layer (X) 11 may be unevenly distributed on one main surface side in the thickness direction of the glass fiber reinforced layer 10. Figure 2 shows an example in which layer (X) 11 is unevenly distributed on the main surface S2 side of the main surfaces S1 and S2 of the glass fiber reinforced layer. The layer configuration of the glass fiber reinforced layer 10 shown in Figure 2 can also be considered as a layer configuration in which layer (Y) 21 is provided on the main surface U1 of layer (X) 11.

[0024] In Figures 1 and 2, the layer (Y) preferably contains only a thermoplastic elastomer (E).

[0025] Although not shown in the diagram, the glass fiber reinforced layer may also have a glass fiber layer throughout its entirety. In this case, the glass fiber reinforced layer typically consists only of a layer (X) containing glass fibers and a thermoplastic elastomer (E).

[0026] Preferably, glass cloth is used as the glass fiber 1. When the glass fiber reinforced layer 10 includes glass cloth as the glass fiber 1, it usually has a structure in which thermoplastic elastomer (E) 2 is impregnated into the glass cloth.

[0027] When the glass fiber reinforced layer includes glass cloth, the ratio (T2 / T1) of the thickness of the glass fiber reinforced layer (thickness T2 in Figure 1) to the thickness of the glass cloth (thickness T1 in Figure 1) is usually 1 or more, may be 1.2 or more, may be 1.5 or more, is usually 5 or less, preferably 4 or less, and more preferably 3 or less. This is because, by having the ratio of the thickness of the glass fiber reinforced layer to the thickness of the glass cloth within the above range, it is possible to create a glass fiber reinforced layer in which the occurrence of creases in the glass fiber reinforced layer due to bending for a certain period of time is effectively suppressed.

[0028] There are no restrictions on the thickness of the glass cloth, and it can be appropriately selected depending on the application of the glass fiber reinforced layer. However, it is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and usually 300 μm or less, preferably 200 μm or less, and more preferably 100 μm or less. This is because having the glass cloth thickness within the above range effectively suppresses the occurrence of creases in the glass fiber reinforced layer due to bending for a certain period of time.

[0029] There are no restrictions on the thickness of the glass fiber reinforcement layer, and it can be appropriately selected depending on the application. However, it is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and usually 500 μm or less, preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less. This is because having the glass fiber reinforcement layer thickness within the above range effectively suppresses the occurrence of creases in the glass fiber reinforcement layer due to bending for a certain period of time.

[0030] When the glass fiber layer includes a layer other than glass cloth, it is preferable that the ratio of the thickness of the glass fiber reinforcement layer to the glass fiber layer, the thickness of the glass fiber layer, and the thickness of the glass fiber reinforcement layer are within the range described above for the case where the glass fiber layer is glass cloth, specifically the ratio of the thickness of the glass fiber reinforcement layer to the glass cloth, the thickness of the glass cloth, and the thickness of the glass fiber reinforcement layer.

[0031] The total light transmittance of the glass fiber reinforced layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more. The total light transmittance can be measured using an ultraviolet-visible spectrometer in the wavelength range of 400 nm to 700 nm.

[0032] <3. Components of the glass fiber reinforced layer> The glass fiber reinforced layer contains at least glass fibers and a thermoplastic elastomer (E).

[0033] (Glass Fiber) Glass fiber is a fibrous material obtained by stretching glass, and also a thread-like or cloth-like material obtained by processing it.

[0034] As the glass material constituting the glass fibers, known materials can be used, such as E glass, C glass, AR glass, S glass, T glass, quartz glass, etc.

[0035] Examples of glass fibers include glass filaments; glass strands (made by bundling multiple glass filaments, e.g., 200 to 400 strands); glass yarns (made by twisting glass strands); and glass cloths such as nonwoven fabrics and glass cloths containing glass filaments or glass yarns. Glass filaments may be included, for example, in a cotton-like form.

[0036] There are no restrictions on the refractive index of the glass fibers, and it can be appropriately selected depending on the application of the glass fiber reinforced layer. However, it is usually 1.40 or higher, preferably 1.45 or higher, more preferably 1.50 or higher, and usually 1.80 or lower, preferably 1.75 or lower, more preferably 1.70 or lower. This is because having the refractive index of the glass fibers within the above range allows for a smaller refractive index difference with the thermoplastic elastomer (E), resulting in a glass fiber reinforced layer with good transparency. The refractive index of the glass fibers can be determined, for example, by impregnating them in a refractive solution, sandwiching them between glass substrates, and measuring the haze. More specifically, multiple refractive solutions are prepared with a constant refractive index difference (for example, in increments of 0.004), and the haze of a sample impregnated with each solution and sandwiched between glass substrates is measured using a haze meter. The refractive index of the refractive solution when the haze of the sample becomes 0% can be determined as the refractive index of the glass fibers. General-purpose refractive solutions and haze meters can be used.

[0037] Among the glass fibers mentioned above, glass cloth is preferred. Glass cloth is a fabric woven using glass filaments or glass threads, and is usually a woven fabric composed of warp and weft threads. By having a form in which the glass fibers are woven regularly, the stretching of the glass fiber reinforced layer in the bending direction, especially the stretching when bent perpendicular to the warp and weft threads, can be effectively suppressed, and thus the occurrence of creases can be effectively suppressed.

[0038] The woven composition of glass cloth can be any conventionally known woven composition, such as plain weave, twill weave, diagonal weave, satin weave, etc.

[0039] There are no restrictions on the fiber diameter of the glass filaments contained in the glass cloth, and it can be appropriately selected depending on the application of the glass fiber reinforced layer, but it is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, preferably 15 μm or less, more preferably 13 μm or less, and even more preferably 10 μm or less. This is because the fiber diameter of the glass filaments is within the above range, allowing the thermoplastic elastomer (E) to be well retained inside the glass cloth.

[0040] There is no restriction on the density of the glass cloth, which can be appropriately selected according to the application of the glass fiber-reinforced layer. Usually, it is 10 g / m ２ or more, preferably 20 g / m ２ or more, more preferably 30 g / m ２ or more, and usually 300 g / m ２ or less, preferably 200 g / m ２ or less, more preferably 100 g / m ２ or less. When the density of the glass cloth is within the above range, the thermoplastic elastomer (E) can be well retained inside the glass cloth.

[0041] The content ratio of glass fibers relative to 100% by weight of the glass fiber-reinforced layer is not particularly limited, and can be appropriately selected according to the application of the glass fiber-reinforced layer. Usually, it is 20% by weight or more, preferably 25% by weight or more, more preferably 30% by weight or more, and usually 60% by weight or less, preferably 55% by weight or less, more preferably 50% by weight or less. When the content ratio of glass fibers is within the above range, the generation of creases on the glass fiber-reinforced layer caused by bending for a certain period of time can be effectively suppressed.

[0042] (Thermoplastic Elastomer (E)) The thermoplastic elastomer (E) is a thermoplastic elastomer having a peak of loss tangent tanδ at -20°C or lower, and a storage modulus of 1 MPa or more and 1000 MPa or less.

[0043] Here, the loss tangent tanδ (loss modulus / storage modulus) of the thermoplastic elastomer (E) is measured by the following method: prepare a rectangular test piece of 200 µm thickness, 10 mm width and 40 mm length from the thermoplastic elastomer (E), and measure with a dynamic viscoelasticity measuring device under the conditions of measurement temperature range: -120°C to 200°C, heating rate: 4°C / min, strain: 0.05%, and measurement frequency: 1 Hz, and the value obtained represents the loss tangent tanδ (loss modulus / storage modulus). In addition, the peak of loss tangent tanδ refers to the peak of loss tangent tanδ when loss tangent tanδ is graphed with temperature on the horizontal axis and loss tangent tanδ on the vertical axis. Therefore, the peak position of loss tangent tanδ (sometimes referred to as "peak temperature") usually represents the temperature at which loss tangent tanδ reaches a maximum value.

[0044] Furthermore, the storage modulus of the thermoplastic elastomer (E) refers to the storage modulus at 23°C measured with a dynamic viscoelasticity measuring device from a rectangular test piece of 50 μm thickness, 10 mm width and 40 mm length prepared from the thermoplastic elastomer (E), under the conditions of a heating rate of 4°C / min, a strain of 0.05%, and a measurement frequency of 1 Hz.

[0045] The peak position of the loss tangent tanδ of the thermoplastic elastomer (E) is usually -20°C or lower, preferably -25°C or lower, more preferably -30°C or lower, and is usually -100°C or higher, preferably -90°C or higher, more preferably -80°C or higher. This is because when the peak position of tanδ falls within the above range, the softness of the thermoplastic elastomer (E) can be stably exhibited over a wide temperature range, and the effect of suppressing the generation of creases on the glass fiber reinforced layer caused by bending for a certain period of time can be highly exhibited.

[0046] Furthermore, the value of tanδ at the peak position of -20°C or lower is usually 0.01 or more, preferably 0.05 or more, more preferably 0.1 or more, and is usually 1 or less, preferably 0.7 or less, more preferably 0.5 or less. This is because when the value of tanδ at the peak position of -20°C or lower falls within the above range, the softness of the thermoplastic elastomer (E) can be stably exhibited over a wide temperature range, and the effect of suppressing the generation of creases on the glass fiber reinforced layer caused by bending for a certain period of time can be highly exhibited.

[0047] Furthermore, regarding the value of tanδ at 23°C, although it is desirable that the lower limit is as small as possible, it is usually 0.001 or more. In addition, the value of tanδ at 23°C is usually 0.3 or less, preferably 0.2 or less, more preferably 0.15 or less. This is because when the value of tanδ at 23°C falls within the above range, while maintaining the softness of the thermoplastic elastomer (E), the effect of suppressing the generation of creases on the glass fiber reinforced layer caused by bending for a certain period of time can be highly exhibited.

[0048] The thermoplastic elastomer (E) may normally have a tanδ peak in the range of 40°C to 200°C, and the value of tanδ may exceed 1 in the range of 40°C to 200°C. If the softening temperature Tm is defined as the temperature at which tanδ has a peak in the range of 40°C to 200°C, or the temperature at which it first exceeds 1, then Tm is preferably 60°C or higher, more preferably 80°C or higher, even more preferably 100°C or higher, preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower. Having Tm within the above range can improve the durability of the glass fiber reinforced layer in high-temperature environments.

[0049] The storage modulus of the thermoplastic elastomer (E) at 25°C and 1 Hz is typically 1 MPa or higher, preferably 5 MPa or higher, more preferably 10 MPa or higher, and typically 1000 MPa or lower, preferably 700 MPa or lower, more preferably 500 MPa or lower, and even more preferably 300 MPa or lower. This is because having the storage modulus within the above range allows for a high level of suppression of the occurrence of creases in the glass fiber reinforced layer due to bending over a certain period of time.

[0050] There are no restrictions on the refractive index of the thermoplastic elastomer (E), and it can be appropriately selected depending on the application of the glass fiber reinforced layer, but it is usually 1.40 or higher, preferably 1.45 or higher, more preferably 1.50 or higher, and usually 1.80 or lower, preferably 1.75 or lower, more preferably 1.70 or lower. This is because having the refractive index of the thermoplastic elastomer (E) within the above range allows for a small difference in refractive index with the glass fibers, resulting in a glass fiber reinforced layer with good transparency. The refractive index of the thermoplastic elastomer (E) can be measured, for example, by an Abbe refractometer.

[0051] There is no limit to the difference between the refractive index of the glass fiber and the refractive index of the thermoplastic elastomer (E). However, from the viewpoint of improving the transparency of the glass fiber reinforced layer, the absolute value of the difference between the refractive index of the glass fiber and the refractive index of the thermoplastic elastomer (E) is preferably 0.07 or less, more preferably 0.06 or less, even more preferably 0.01 or less, particularly preferably 0.003 or less, and ideally 0.

[0052] There are no restrictions on the content ratio of thermoplastic elastomer (E) in the glass fiber reinforced layer, and it is appropriately selected depending on the form of the glass fibers, but it is usually 50% by weight or more, preferably 55% by weight or more, more preferably 60% by weight or more, and usually 90% by weight or less, preferably 85% by weight or less, more preferably 80% by weight or less.

[0053] Thermoplastic elastomer (E) typically comprises a polymer and optional components that may be included as needed. The polymer that may be included in thermoplastic elastomer (E) may be a copolymer, a homopolymer, or a mixture of copolymers (polymer blend). The polymer may also be a hydride of copolymers, homopolymers, and mixtures thereof, or a modified product of copolymers or hydrides of copolymers, etc. Examples of thermoplastic elastomer (E) include amide-based thermoplastic elastomers; ester-based thermoplastic elastomers; olefin-based thermoplastic elastomers; aromatic vinyl compound-conjugated diene-based thermoplastic elastomers (e.g., styrene-based thermoplastic elastomers); urethane-based thermoplastic elastomers; and thermoplastic rubber crosslinked materials. Thermoplastic elastomer (E) may be used alone or in combination of two or more types.

[0054] As the thermoplastic elastomer (E), an aromatic vinyl compound-conjugated diene thermoplastic elastomer is preferred. An aromatic vinyl compound-conjugated diene thermoplastic elastomer means an elastomer containing one or more selected from the group consisting of a block copolymer having a polymer block (A) mainly composed of aromatic vinyl compound units and a polymer block (B) mainly composed of chain-like conjugated diene compound units; a hydride of the block copolymer; a modified product of the block copolymer or the hydride of the block copolymer; and combinations thereof. An example of a modified product is a product obtained by modifying the block copolymer or the hydride of the block copolymer with a modifying component such as an alkoxysilane, a carboxylic acid, or a carboxylic acid anhydride. Hereinafter, the block copolymer having the polymer block (A) and the polymer block (B) will also be called a specific block copolymer. Furthermore, the specific block copolymer and the hydride of the specific block copolymer together will also be called a specific block copolymer, etc.

[0055] The aforementioned specific block copolymer, which has a polymer block (A) mainly composed of aromatic vinyl compound units and a polymer block (B) mainly composed of chain-like conjugated diene compound units, is also called an aromatic vinyl compound-conjugated diene block copolymer, and the hydride of the specific block copolymer is also called a hydrogenated aromatic vinyl compound-conjugated diene block copolymer.

[0056] Furthermore, an aromatic vinyl compound unit refers to a structural unit having a structure formed by polymerizing aromatic vinyl compounds. In addition, a chain-like conjugated diene compound unit refers to a structural unit having a structure formed by polymerizing chain-like conjugated diene compounds. Chain-like conjugated diene compounds may be linear or branched. In a given polymer block, the main component unit means a unit that makes up 50% by weight or more of the polymer block, with the polymer block being 100% by weight.

[0057] Examples of aromatic vinyl compounds corresponding to aromatic vinyl compound units include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, 4-monochlorostyrene, dichlorostyrene, 4-monofluorostyrene, and 4-phenylstyrene. These may be used individually or in combination of two or more in any ratio. Among these, those that do not contain polar groups are preferred in terms of hygroscopicity. Furthermore, styrene is particularly preferred from the viewpoint of industrial availability and impact resistance.

[0058] The content of aromatic vinyl compound units in polymer block (A) is preferably 90% by weight or more, more preferably 95% by weight or more, and particularly preferably 99% by weight or more. By increasing the amount of aromatic vinyl compound units in polymer block (A) as described above, the heat resistance of thermoplastic elastomer (E) can be improved.

[0059] The polymer block (A) may contain any structural units other than aromatic vinyl compound units. Examples of arbitrary structural units include chain-like conjugated diene compound units and structural units having a structure formed by polymerizing vinyl compounds other than aromatic vinyl compounds.

[0060] Examples of chain-conjugated diene compounds corresponding to chain-conjugated diene compound units include those similar to those given as examples of chain-conjugated diene compounds corresponding to chain-conjugated diene compound units in polymer block (B). Furthermore, a single chain-conjugated diene compound may be used alone, or two or more types may be used in any ratio.

[0061] Examples of vinyl compounds other than aromatic vinyl compounds include chain vinyl compounds; cyclic vinyl compounds; vinyl compounds having a nitrile group, alkoxycarbonyl group, hydroxycarbonyl group, or halogen group; unsaturated cyclic acid anhydrides; and unsaturated imide compounds. Among these, vinyl compounds that do not contain polar groups, such as chain olefins like ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-eicosene, 4-methyl-1-pentene, and 4,6-dimethyl-1-heptene; and cyclic olefins like vinylcyclohexane, are preferred in terms of hygroscopicity. Among these, chain olefins are more preferred, and ethylene and propylene are particularly preferred. Furthermore, these may be used individually or in combination of two or more in any ratio.

[0062] The content of any structural unit in the polymer block (A) is preferably 10% by weight or less, more preferably 5% by weight or less, particularly preferably 1% by weight or less, and is usually 0% by weight or more, and may be 0% by weight.

[0063] The number of polymer blocks (A) in one molecule of a specific block copolymer is preferably two or more, preferably five or fewer, more preferably four or fewer, and particularly preferably three or fewer. Multiple polymer blocks (A) in one molecule may be the same or different from one another.

[0064] The polymer block (B) of the specific block copolymer has a chain-like conjugated diene compound unit. Examples of chain-like conjugated diene compounds corresponding to the chain-like conjugated diene compound unit of this polymer block (B) include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene. These may be used individually or in combination of two or more in any ratio. Among these, those that do not contain polar groups are preferred in terms of hygroscopicity, and 1,3-butadiene and isoprene are particularly preferred.

[0065] The content of chain-like conjugated diene compound units in polymer block (B) is preferably 90% by weight or more, more preferably 95% by weight or more, and particularly preferably 99% by weight or more. By increasing the amount of chain-like conjugated diene compound units in polymer block (B) as described above, the flexibility of the thermoplastic elastomer (E) at low temperatures can be improved.

[0066] Polymer block (B) may contain arbitrary structural units other than chain-like conjugated diene compound units. Examples of arbitrary structural units include aromatic vinyl compound units and structural units having a structure formed by polymerizing vinyl compounds other than aromatic vinyl compounds. Examples of these aromatic vinyl compound units and structural units having a structure formed by polymerizing vinyl compounds other than aromatic vinyl compounds include the units exemplified as potentially included in polymer block (A).

[0067] The content of any structural unit in the polymer block (B) is preferably 10% by weight or less, more preferably 5% by weight or less, particularly preferably 1% by weight or less, and is usually 0% by weight or more, and may be 0% by weight. In particular, by lowering the content of aromatic vinyl compound units in the polymer block (B), the flexibility of the thermoplastic elastomer (E) at low temperatures can be improved.

[0068] The number of polymer blocks (B) in one molecule of a specific block copolymer is usually one or more, but it may be two or more. When the number of polymer blocks (B) in a specific block copolymer is two or more, the polymer blocks (B) may be the same or different from each other.

[0069] The block form of the specific block copolymer may be a chain-type block or a radial-type block. Among these, the chain-type block is preferred because it has excellent mechanical strength. When the specific block copolymer has a chain-type block form, it is preferable that both ends are polymer blocks (A) because this can suppress the stickiness of the thermoplastic elastomer (E) to a desired low level.

[0070] Particularly preferred block configurations for a specific block copolymer are a triblock copolymer in which polymer block (A) is bonded to both ends of polymer block (B), as represented by (A)-(B)-(A); and a pentablock copolymer in which polymer block (B) is bonded to both ends of polymer block (A), and polymer block (A) is further bonded to the other ends of both polymer block (B), as represented by (A)-(B)-(A)-(B)-(A). In particular, the (A)-(B)-(A) triblock copolymer is particularly preferred because it is easy to manufacture and allows physical properties such as viscosity to be within a desired range.

[0071] In a specific block copolymer, the ratio (wA / wB) of the weight fraction wA of the total polymer block (A) in the entire specific block copolymer to the weight fraction wB of the total polymer block (B) in the entire specific block copolymer is preferably 30 / 70 or more, more preferably 40 / 60 or more, even more preferably 45 / 55 or more, preferably 80 / 20 or less, more preferably 70 / 30 or less, and even more preferably 55 / 45 or less. By setting the ratio wA / wB to be above the lower limit of the above range, the heat resistance of the thermoplastic elastomer (E) can be improved. Furthermore, by setting it to be below the upper limit, the flexibility of the thermoplastic elastomer (E) can be increased, making it possible to effectively suppress the occurrence of creases in the glass fiber reinforced layer due to bending for a certain period of time.

[0072] The weight-average molecular weight (Mw) of the specified block copolymer is preferably 30,000 or more, more preferably 40,000 or more, particularly preferably 50,000 or more, preferably 200,000 or less, more preferably 150,000 or less, and particularly preferably 100,000 or less. The molecular weight distribution (Mw / Mn) of the specified block copolymer is preferably 3 or less, more preferably 2 or less, particularly preferably 1.5 or less, and preferably 1.0 or more. Here, Mn represents the number-average molecular weight. The weight-average molecular weight and molecular weight distribution of the specified block copolymer can be measured as polystyrene equivalent values ​​by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as the solvent.

[0073] The hydride of the specific block copolymer is obtained by hydrogenating the unsaturated bonds of the specific block copolymer described above. Here, the unsaturated bonds of the block copolymer include both aromatic and non-aromatic carbon-carbon unsaturated bonds of the main chain and side chains of the block copolymer. The hydrogenation rate is preferably 90% or more, more preferably 97% or more, and particularly preferably 99% or more of the total unsaturated bonds of the block copolymer. The higher the hydrogenation rate, the better the heat resistance and light resistance of the thermoplastic elastomer (E). Here, the hydrogenation rate of the hydride is １ This can be determined by measurement using H-NMR.

[0074] In particular, the hydrogenation rate of the non-aromatic unsaturated bonds is preferably 95% or more, more preferably 99% or more. By increasing the hydrogenation rate of the non-aromatic carbon-carbon unsaturated bonds, the light resistance and oxidation resistance of the thermoplastic elastomer (E) can be further improved.

[0075] Furthermore, the hydrogenation rate of the aromatic carbon-carbon unsaturated bond is preferably 90% or more, more preferably 93% or more, and particularly preferably 95% or more. By increasing the hydrogenation rate of the carbon-carbon unsaturated bond of the aromatic ring, the glass transition temperature of the polymer block obtained by hydrogenating polymer block (A) is increased, thereby effectively improving the heat resistance of the thermoplastic elastomer (E). In addition, the photoelastic coefficient of the thermoplastic elastomer (E) can be lowered, suppressing the occurrence of unintended retardation.

[0076] The weight-average molecular weight (Mw) of the hydride of the specific block copolymer is preferably 30,000 or more, more preferably 40,000 or more, particularly preferably 45,000 or more, preferably 200,000 or less, more preferably 150,000 or less, and particularly preferably 100,000 or less. The molecular weight distribution (Mw / Mn) of the hydride of the specific block copolymer is preferably 3 or less, more preferably 2 or less, particularly preferably 1.5 or less, and preferably 1.0 or more. By keeping the weight-average molecular weight Mw and molecular weight distribution Mw / Mn of the hydride of the specific block copolymer within the above ranges, the mechanical strength and heat resistance of the thermoplastic elastomer (E) can be improved. The weight-average molecular weight and molecular weight distribution of the hydride of the block copolymer can be measured in polystyrene equivalent values ​​by gel permeation chromatography using tetrahydrofuran as the solvent.

[0077] In the hydrogenated product of a specific block copolymer, the ratio (wA / wB) of the weight fraction wA of the total polymer block (A) to the weight fraction wB of the total polymer block (B) to the total polymer block is usually the same as the ratio wA / wB in the specific block copolymer before hydrogenation.

[0078] Specific examples of modified products of specific block copolymers or hydrides of specific block copolymers include those modified with silicon atom-containing polar groups. An example of a silicon atom-containing polar group is an alkoxysilyl group. Modified products with alkoxysilyl groups are obtained by bonding alkoxysilyl groups to the specific block copolymer or its hydride. In this case, the alkoxysilyl group may be directly bonded to the specific block copolymer or its hydride, or it may be bonded via a divalent organic group such as an alkylene group.

[0079] An example of a method for bonding an alkoxysilyl group to a specific block copolymer or its hydride is to react the specific block copolymer or its hydride with an ethylenically unsaturated silane compound in the presence of a peroxide.

[0080] As ethylenically unsaturated silane compounds, those that can be graft polymerized with specific block copolymers and that can introduce alkoxysilyl groups into specific block copolymers can be used. Examples of such ethylenically unsaturated silane compounds include vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, p-styryltrimethoxysilane, p-styryltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, and 2-norbornene-5-yltrimethoxysilane. Among these, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, and p-styryltrimethoxysilane are preferred. Furthermore, the ethylenically unsaturated silane compound may be used alone or in combination of two or more types in any ratio.

[0081] The amount of ethylenically unsaturated silane compound is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, particularly preferably 0.3 parts by weight or more, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, and particularly preferably 3 parts by weight or less, based on 100 parts by weight of the specific block copolymer etc. before the introduction of the alkoxysilyl group.

[0082] As peroxides, for example, those described in International Publication No. 2016 / 153030 can be used.

[0083] The thermoplastic elastomer (E) preferably contains one or more selected from the group consisting of aromatic vinyl compound-conjugated diene block copolymers, hydrogenated aromatic vinyl compound-conjugated diene block copolymers, aromatic vinyl compound-conjugated diene block copolymers modified by silicon atom-containing polar groups, and hydrogenated aromatic vinyl compound-conjugated diene block copolymers modified by silicon atom-containing polar groups. The storage modulus at 23°C of these block copolymers can be adjusted by changing the weight ratio of polymer block (A) and polymer block (B) contained therein.

[0084] As described above, the thermoplastic elastomer (E) may contain optional components in addition to the polymer. The polymer content in the thermoplastic elastomer (E) can be, for example, in the range of 25% by weight or more and 100% by weight or less. As an example, the lower limit of the polymer content in the thermoplastic elastomer (E) is preferably 50% by weight or more, more preferably 80% by weight or more, and even more preferably 90% by weight or more. As another example, the lower limit of the polymer content in the thermoplastic elastomer (E) is preferably 95% by weight or more, more preferably 97% by weight or more, and even more preferably 98% by weight or more. The upper limit of the polymer content in the thermoplastic elastomer (E) is usually 100% by weight or less. The polymer content in the thermoplastic elastomer (E) may be 100% by weight. In this case, the thermoplastic elastomer (E) contains only the polymer.

[0085] Examples of optional components include plasticizers; light stabilizers such as hindered amine-based light stabilizers; ultraviolet absorbers such as benzophenone-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, and benzotriazole-based ultraviolet absorbers; antioxidants such as phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants; lubricants; fillers; and colorants such as pigments and dyes. Any optional component may be used individually or in combination of two or more components in any ratio.

[0086] Examples of plasticizers include polybutene, polyisobutene, hydrogenated polyisobutene, hydrogenated polyisoprene, hydrogenated 1,3-pentadiene petroleum resin, hydrogenated cyclopentadiene petroleum resin, and hydrogenated styrene-indene petroleum resin. Furthermore, a single type of plasticizer may be used alone, or two or more types may be used in any ratio. Among these, polybutene is particularly preferred as a plasticizer.

[0087] The plasticizer content in the thermoplastic elastomer (E) can be, for example, in the range of 10% by weight or more and 75% by weight or less. As an example, the plasticizer content in the thermoplastic elastomer (E) is preferably 10% by weight or more, more preferably 20% by weight or more, even more preferably 25% by weight or more, preferably less than 50% by weight, more preferably 45% by weight or less, and even more preferably 40% by weight or less. As another example, the plasticizer content in the thermoplastic elastomer (E) is preferably 50% by weight or more, more preferably 60% by weight or more, even more preferably 70% by weight or more, and preferably 75% by weight or less. This is because setting the plasticizer content within the above range makes it easier to adjust the peak position of tanδ and the storage modulus at 23°C to a desired range.

[0088] <4. Method for Manufacturing the Glass Fiber Reinforced Layer> The glass fiber reinforced layer described above can be manufactured by any method. One preferred example of a method for manufacturing the glass fiber reinforced layer is a manufacturing method using the lamination method.

[0089] A manufacturing method using the lamination method typically includes a step (I) of preparing two thermoplastic elastomer layers containing a thermoplastic elastomer (E), and a step (II) of sandwiching glass fibers between the two thermoplastic elastomer layers and bonding them together.

[0090] In step (I), the method for preparing the thermoplastic elastomer layer is arbitrary, but it is usually prepared by forming a thermoplastic elastomer layer.

[0091] The method for forming the thermoplastic elastomer layer is arbitrary, but one example is to prepare a release sheet, apply a liquid composition containing a thermoplastic elastomer (E) to the main surface (first main surface) of the release sheet by a conventionally known method to obtain a layer of the liquid composition, and then dry the layer of the liquid composition as needed to form the thermoplastic elastomer layer.

[0092] A release sheet typically comprises a base material and a release layer formed on the main surface of the base material. The base material can be any material capable of supporting a thermoplastic elastomer layer, but from the viewpoint of improving ease of peeling from the thermoplastic elastomer layer, a resin film is preferred.

[0093] Examples of resins contained in resin films used as substrates include vinyl chloride resins such as polyvinyl chloride and polyvinylidene chloride; polyimide resins; polycarbonate resins; acrylic resins; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; poly(α-olefin) resins such as polyethylene, polypropylene, and polymethylpentene; cyclic olefin resins such as norbornene polymers; and fluororesins such as poly(tetrafluoroethylene). The polymers contained in these resins may be homopolymers or copolymers. These resins may be used individually or in combination of two or more in any proportion.

[0094] Here, polyimide resin refers to a resin containing polymers whose repeating units have an imide structure (-(C=O)-(NR)-(C=O)-: R represents a substituent such as a hydrogen atom or an aryl group). Polycarbonate resin refers to a resin containing polymers whose repeating units have a carbonate structure (-O-(C=O)-O-). Acrylic resin refers to a resin containing polymers whose repeating units have a structure obtained by polymerizing (meth)acrylic acid or its derivatives. Examples of derivatives of (meth)acrylic acid include (meth)acrylic acid esters such as methyl methacrylate; (meth)acrylamide; and (meth)acrylonitrile.

[0095] The release layer may be provided on only one main surface of the substrate, or on each of the two main surfaces. The release layer usually contains a release agent. Examples of release agents include silicone-based release agents such as polydimethylsiloxane, fluorine-based release agents such as alkyl fluorides, and long-chain alkyl-based release agents such as polyolefins.

[0096] You may purchase and use commercially available release sheets.

[0097] Examples of methods for applying a liquid composition containing a thermoplastic elastomer (E) to the first main surface of a release sheet include, but are not limited to, curtain coating; extrusion coating; roll coating; spin coating; dip coating; bar coating; spray coating; slide coating; printing coating methods such as screen printing and inkjet printing; gravure coating; die coating; and gap coating.

[0098] A liquid composition containing a thermoplastic elastomer (E) may be prepared, for example, by heating a composition containing the thermoplastic elastomer (E) to a temperature above the glass transition temperature of the thermoplastic elastomer (E) to melt it, or by dissolving or dispersing the thermoplastic elastomer (E) in a solvent to prepare a liquid composition.

[0099] Examples of solvents that may be included in the liquid composition include alicyclic hydrocarbon solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane; aromatic hydrocarbon solvents such as toluene; cyclic ether solvents such as tetrahydrofuran; and aliphatic hydrocarbon solvents such as decane and dodecane. The solvent may be used alone or in combination of two or more in any proportion.

[0100] When the liquid composition contains a solvent, from the viewpoint of easily obtaining a thermoplastic elastomer layer of the desired thickness, the weight ratio of the thermoplastic elastomer (E) is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, even more preferably 40 parts by weight or more, preferably 100 parts by weight or less, more preferably 90 parts by weight or less, and even more preferably 80 parts by weight or less, per 100 parts by weight of the solvent.

[0101] Examples of methods for drying a layer of liquid composition include natural drying, heat drying, reduced-pressure drying, and heated-reduced-pressure drying.

[0102] Another example of a method for forming a thermoplastic elastomer layer is a method in which a thermoplastic elastomer (E) is melted and extruded to form the thermoplastic elastomer layer.

[0103] In step (II), a preferred method for bonding the glass fibers between the two thermoplastic elastomer layers is to heat and pressurize the laminate with the glass fibers sandwiched between the two thermoplastic elastomer layers. This is because it allows the thermoplastic elastomer (E) to melt and impregnate the glass fibers, and also allows the two thermoplastic elastomer layers to bond well.

[0104] Examples of pressurizing devices are not limited to vacuum laminators, which perform lamination by pressurizing a laminate under vacuum; and roller laminators, which perform lamination by pressurizing a laminate under atmospheric pressure using rollers. Examples of pressurizing methods in vacuum laminators include roller methods, diaphragm methods that apply pressure using a flexible diaphragm, and vacuum heating and pressurizing methods that press metal plates against a laminate placed between opposing metal plates while applying heat. The pressure is preferably 0.01 MPa or higher, more preferably 0.05 MPa or higher, particularly preferably 0.1 MPa or higher, preferably 1 MPa or lower, more preferably 0.75 MPa or lower, and particularly preferably 0.5 MPa or lower.

[0105] Step (II) is preferably carried out in a reduced-pressure environment. This effectively prevents water and air from being trapped within the glass fiber reinforced layer. The specific vacuum level of the reduced-pressure environment is preferably 1000 Pa or less, more preferably 200 Pa or less, and particularly preferably 100 Pa or less.

[0106] The pressurization time in process (II) is, for example, 1 minute or more, for example, 2 minutes or more, for example, 60 minutes or less, for example, 30 minutes or less.

[0107] The heating temperature is preferably Tm°C or higher, more preferably Tm + 30°C, even more preferably Tm + 50°C or higher, preferably Tm + 170°C or lower, more preferably Tm + 150°C or lower, and even more preferably Tm + 120°C or lower. Here, Tm represents the peak temperature of tanδ in the thermoplastic elastomer (E) in the range of 40°C to 200°C or the temperature at which it first exceeds 1 (softening temperature).

[0108] Another preferred example of a method for manufacturing a glass fiber reinforced layer is a manufacturing method using a coating method.

[0109] In a manufacturing method using a coating method, a typical method involves preparing a glass fiber layer made of glass fibers, and then applying a liquid composition containing a thermoplastic elastomer (E) to the glass fiber layer to impregnate it and form a thermoplastic elastomer layer.

[0110] The glass fiber layer, the liquid compound, and the method of applying them are the same as described above. Furthermore, the amount of liquid composition applied is adjusted to the extent that the glass fibers are impregnated with the liquid composition, taking into consideration the density and thickness of the glass fiber layer.

[0111] From the viewpoint of thoroughly impregnating the glass fiber layer with the liquid composition, it is preferable to dry for a long period of time. For example, it is preferable to dry for about 5 to 60 minutes at a temperature range of 23°C to 80°C.

[0112] <5. Use of Glass Fiber Reinforced Layer> The glass fiber reinforced layer according to the present embodiment is preferably used as a constituent layer of a flexible device. The term "flexible device" refers to a device used in an article that can be used while being curved, for example, an article that is deformed along a curved surface, bent, or wound. Examples of flexible devices include a protective layer provided on the front surface of a display panel such as a liquid crystal display panel or an organic electroluminescence panel. In addition, since the glass fiber reinforced layer of a display panel can suppress the occurrence of creases caused by bending for a certain period of time, when used as a protective layer on the front surface of the display panel, it can suppress the deterioration of display quality caused by creases.

[0113] Further, other examples of flexible devices include supports in wiring substrates such as flexible displays and touch panels. Since the glass fiber reinforced layer can suppress the occurrence of creases caused by bending for a certain period of time, it can suppress wire breakage when a flexible display or the like is bent. In addition, by containing glass fibers, the coefficient of linear expansion of the glass fiber reinforced layer can be reduced, and a support with less deformation due to temperature can be obtained.

[0114] Further, other uses of the glass fiber reinforced layer include a protective layer for projector screens and the like.

[0115] Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the Examples shown below, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and equivalents thereof.

[0116] In the following description, "%" and "part" representing amounts are based on weight unless otherwise specified. In addition, the operations described below were performed under the conditions of normal temperature (20°C ± 15°C) and normal pressure (1 atm) unless otherwise specified.

[0117] <Evaluation Method> (Method for Measuring Hydrogenation Rate of Polymer) The hydrogenation rate of the polymer is measured using ortho-dichlorobenzene-d ４ as a solvent at 145°C, １The measurement was performed using 1H-NMR.

[0118] (Method for measuring the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polymers) The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polymers were measured as polystyrene equivalent values ​​using a gel permeation chromatography (GPC) system (HLC-8320, manufactured by Tosoh Corporation). For the measurement, an H-type column (manufactured by Tosoh Corporation) was used as the column, and tetrahydrofuran was used as the solvent. The measurement temperature was 40°C.

[0119] (Tensile elongation) The tensile elongation of the thermoplastic elastomers (solid content of the liquid composition) in Examples 1 to 3 at 23°C was measured in accordance with JIS K7113.

[0120] (tanδ and Tm) Films with a thickness of 200 μm were formed using the liquid compositions of Examples 1 to 3. Test pieces measuring 10 mm wide x 40 mm long were cut from the film, and tanδ was measured using a dynamic viscoelasticity measuring device (Hitachi High-Tech Science Corporation "DMS6100"). The measurement conditions were a measurement temperature range of -120°C to 200°C, a frequency of 1 Hz, and a heating rate of 4°C / min. From the measurement results, a graph was created with the measurement temperature range on the horizontal axis and the value of tanδ on the vertical axis, and the peak position and value of tanδ, as well as Tm, were read.

[0121] (Storage Modulus) Films with a thickness of 50 μm were formed using the liquid compositions of Examples 1 to 3. Test pieces measuring 10 mm in width and 40 mm in length were cut from the film, and the storage modulus was measured using a dynamic viscoelasticity measuring device (Hitachi High-Tech Science Corporation's "DMS6100"). The measurement conditions were a frequency of 1 Hz and a heating rate of 4 °C / min, and the storage modulus at 23 °C was read.

[0122] (Refractive Index) The refractive index of the glass cloth was measured at a wavelength of 589 nm using a refractive solution and a haze meter. In addition, the thermoplastic elastomers (solid content of the liquid composition) in Examples 1 to 3 were prepared by molding them into films and measured at a wavelength of 589 nm using an Abbe refractometer.

[0123] (Evaluation of creases by bending test) The glass fiber reinforced layers of Examples 1 to 4 and the thermoplastic elastomer layers of Comparative Examples 1 to 3 were bent at a bending radius R of 3 mm and left to stand for 24 hours, after which the presence or absence of creases was evaluated. In addition, the glass fiber reinforced layer of Example 5 and the thermoplastic elastomer layer of Comparative Example 4 were bent at a bending radius R of 1.5 mm and left to stand for 24 hours, after which the presence or absence of creases was evaluated. The evaluation index for creases is as follows: "Angle of crease" refers to the angle (bending angle) between the first part and the second part when the glass fiber reinforced layer or thermoplastic elastomer layer is divided into a first part and a second part by the crease. A: Angle of crease is 0° or more and less than 22.5°. No creases were visible or almost invisible to the naked eye. B: Angle of crease is 22.5° or more and less than 45°. Creases were visible but minor. C: Angle of crease is 45° or more and less than 90°. A crease was visible to the naked eye. D: The angle of the fold is 90° or more. A crease was clearly visible to the naked eye.

[0124] <Production Example 1: Production of Polymer (a) Having Polar Groups Containing Silicon Atoms> (Production of Hydrogenated Block Copolymer) Using styrene as the aromatic vinyl compound and isoprene as the chain-like conjugated diene compound, a hydrogenated block copolymer having a triblock structure in which polymer blocks [A] are bonded to both ends of polymer block [B] was produced by the following procedure.

[0125] In a reactor equipped with a stirring device and thoroughly purged with nitrogen, 256 parts of dehydrated cyclohexane, 25.0 parts of dehydrated styrene, and 0.615 parts of n-dibutyl ether were added. While stirring at 60°C, 1.35 parts of n-butyllithium (15% cyclohexane solution) were added to initiate polymerization, and the reaction was continued at 60°C for 60 minutes with further stirring. At this point, the polymerization conversion rate was 99.5% (the polymerization conversion rate was measured by gas chromatography; the same method was used hereafter).

[0126] Next, 50.0 parts of dehydrated isoprene were added, and stirring was continued at the same temperature for 30 minutes. At this point, the polymerization conversion rate was 99%. Subsequently, 25.0 parts of dehydrated styrene were added, and stirring was continued at the same temperature for 60 minutes. At this point, the polymerization conversion rate was approximately 100%. Then, 0.5 parts of isopropyl alcohol were added to the reaction solution to stop the reaction and obtain solution (i) containing the block copolymer. The weight-average molecular weight (Mw) of the block copolymer in the obtained solution (i) was 44,900, and the molecular weight distribution (Mw / Mn) was 1.03.

[0127] Next, solution (i) was transferred to a pressure reactor equipped with a stirring device, and 4.0 parts of silica-alumina-supported nickel catalyst (E22U, nickel load 60%; manufactured by JGC Chemical Industries, Ltd.) and 350 parts of dehydrated cyclohexane were added to solution (i) as a hydrogenation catalyst and mixed. The reactor was purged with hydrogen gas, and hydrogen was supplied while stirring the solution, and the hydrogenation reaction was carried out at a temperature of 170°C and a pressure of 4.5 MPa for 6 hours to hydrogenate the block copolymer and obtain solution (iii) containing the hydride (ii) of the block copolymer. The weight-average molecular weight (Mw) of the hydride (ii) in solution (iii) was 45,100, and the molecular weight distribution (Mw / Mn) was 1.04.

[0128] After the hydrogenation reaction was complete, solution (iii) was filtered to remove the hydrogenation catalyst. Then, 1.0 part of a xylene solution containing 0.1 part of the phosphorus-based antioxidant 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetrakis-t-butyldibenzo[d,f][1.3.2]dioxaphosfepine (Sumitomo Chemical Co., Ltd., "SumiLizer® GP"; hereinafter referred to as "antioxidant A") was added to the filtered solution (iii) and dissolved to obtain solution (iv).

[0129] Next, solution (iv) was filtered through a ZetaPlus® filter 30H (manufactured by Quno, pore size 0.5 μm to 1 μm), and then sequentially filtered through another metal fiber filter (pore size 0.4 μm, manufactured by Nichidai) to remove minute solid particles. From the filtered solution (iv), the solvent cyclohexane, xylene, and other volatile components were removed using a cylindrical concentrate dryer (product name "Contro", manufactured by Hitachi, Ltd.) at a temperature of 260°C and a pressure of 0.001 MPa or less. The solid particles were then extruded in a molten state into strands from a die directly connected to the concentrate dryer, cooled, and cut with a pelletizer to obtain 85 pellets (v) of polymer (a) containing a block copolymer hydride and antioxidant A. The weight-average molecular weight (Mw) of the hydrogenated block copolymer (hydrogenated block copolymer) in the obtained pellet (v) was 45,000, and the molecular weight distribution (Mw / Mn) was 1.08. The hydrogenation rate was 99.9%. A film-like test piece was prepared from this pellet (v), and the softening temperature Tm was evaluated by the temperature change of tanδ in a dynamic viscoelasticity measuring device, which was found to be 127°C.

[0130] <Example 1> (1-1. Preparation of Liquid Composition) A liquid composition was prepared by mixing 35 parts of polymer (a) produced in Production Example 1, 15 parts of polybutene, and 100 parts of ethylcyclohexane. Using the obtained liquid composition, test specimens were prepared to measure tensile elongation, tanδ, and storage modulus, and measurements were performed using the measurement methods described above. The tanδ peak position was -46°C (tanδ value: 0.29), Tm was 90°C, the storage modulus at 23°C was 65 MPa, the tanδ value at 23°C was 0.09, and the tensile elongation at 23°C was 600%. Therefore, it was confirmed that the solid component contained in this liquid composition corresponds to thermoplastic elastomer (E). The refractive index of this solid component was 1.50.

[0131] (1-2. Manufacturing of the glass fiber reinforced layer) Next, a PET film with a thickness of 38 μm and release layers formed on both sides (Mitsubishi Chemical Corporation's "MRV38", hereinafter also referred to as release PET film) was prepared. The liquid composition was applied to the release PET film so that the film thickness after drying would be 20 μm, and the laminate was dried in a drying oven at 130°C to obtain a laminate. This laminate had a layer structure of (release PET film) / (thermoplastic elastomer layer). The release PET film was peeled off, and a glass cloth with a thickness of 20 μm (Featherfield Co., Ltd., model number N1211100, refractive index n = 1.556 (≒1.56)) was sandwiched between the two thermoplastic elastomer layers, and the layers were bonded together in a vacuum heating laminator at 170°C and 0.8 MPa to obtain a glass fiber reinforced layer with a thickness of 50 μm.

[0132] <Example 2> (2-1. Preparation of Liquid Composition) A liquid composition was prepared by mixing 50 parts of polymer (a) produced in Production Example 1 with 100 parts of ethylcyclohexane. Test specimens were prepared using the obtained liquid composition to measure tensile elongation, tanδ, and storage modulus, and measurements were performed using the measurement methods described above. The tanδ peak position was -41°C (tanδ value: 0.13), Tm was 127°C, the storage modulus at 23°C was 300 MPa, the tanδ value at 23°C was 0.05, and the tensile elongation at 23°C was 520%. Therefore, it was confirmed that the solid component contained in this liquid composition corresponds to thermoplastic elastomer (E). The refractive index of this solid component was 1.50.

[0133] (2-2. Manufacturing of the glass fiber reinforced layer) Next, a glass cloth with a thickness of 20 μm (Featherfield Co., Ltd., model number N1211100, refractive index n = 1.556 (≒1.56)) was prepared, and the liquid composition was applied to the glass cloth so that the film thickness after drying would be 35 μm. The glass fiber reinforced layer was obtained by slowly drying it on a hot plate at 40°C for 30 minutes.

[0134] <Example 3> (3-1. Preparation of Liquid Composition) 30 parts of polymer (a) produced in Production Example 1, 20 parts of polybutene, and 100 parts of ethylcyclohexane were mixed to obtain a liquid composition. Using the obtained liquid composition, test specimens were prepared to measure tensile elongation, tanδ, and storage modulus, and measurements were performed using the measurement methods described above. The tanδ peak position was -46°C (tanδ value 0.33), Tm was 71°C, the storage modulus at 23°C was 10 MPa, the tanδ value at 23°C was 0.11, and the tensile elongation at 23°C was 600%. Therefore, it was confirmed that the solid component contained in this liquid composition corresponds to thermoplastic elastomer (E). The refractive index of this solid component was 1.50.

[0135] (3-2. Manufacturing of glass fiber reinforced layer) A glass fiber reinforced layer was obtained by performing the same procedure as in Example 1, except that the thickness of the obtained glass fiber reinforced layer was 40 μm.

[0136] <Example 4> A glass fiber reinforced layer was obtained by performing the same procedure as in Example 2, except that the liquid composition was applied so that the film thickness after drying was 70 μm.

[0137] <Example 5> A glass fiber reinforced layer was obtained by performing the same procedure as in Example 2.

[0138] <Comparative Example 1> The same procedure as in Example 1 was performed, except that a glass cloth was not sandwiched between the two resin layers, to obtain a thermoplastic elastomer layer with a thickness of 50 μm.

[0139] <Comparative Example 2> A thermoplastic elastomer layer with a thickness of 35 μm was obtained by performing the same procedure as in Example 2, except that the liquid composition was applied to a release PET film instead of glass cloth.

[0140] <Comparative Example 3> The same procedure as in Example 4 was performed, except that the liquid composition was applied to a release PET film instead of glass cloth, to obtain a thermoplastic elastomer layer with a thickness of 70 μm.

[0141] <Comparative Example 4> The same procedure as in Comparative Example 2 was performed to obtain a thermoplastic elastomer layer with a thickness of 35 μm.

[0142] The results for Examples 1-5 and Comparative Examples 1-4 are shown in Tables 1 and 2. The abbreviations in the tables have the following meanings: Polymer (a) (wt%): Content ratio of polymer (a) relative to 100% by weight of thermoplastic elastomer (E) (wt%) Polybutene (wt%): Content ratio of polybutene relative to 100% by weight of thermoplastic elastomer (E) (wt%) tanδ peak position: Represents the temperature of the lower-temperature peak position among the tanδ peaks of the thermoplastic elastomers used in Examples 1-3. Thickness T2 (μm) / Thickness T1 (μm) ratio: Thickness T2 (μm) of the glass fiber reinforced layer relative to the thickness T1 (μm) of the glass cloth

[0143]

[0144]

[0145] 1 Glass fiber 2 Thermoplastic elastomer (E) 10 Glass fiber reinforced layer 11 Layer (X) 21, 22 Layers (Y) U1, U2 Main surface (of the glass fiber layer) S1, S2 Main surface (of the glass fiber reinforced layer) T1 Thickness of the glass fiber layer T2 Thickness of the glass fiber reinforced layer

Claims

1. A glass fiber reinforced layer comprising glass fibers and a thermoplastic elastomer (E), wherein the thermoplastic elastomer (E) has a loss tangent tanδ peaking at -20°C or below, and a storage modulus of 1 MPa or more and 1000 MPa or less.

2. The glass fiber reinforced layer according to claim 1, wherein the thermoplastic elastomer (E) comprises one or more selected from the group consisting of aromatic vinyl compound-conjugated diene block copolymer, hydrogenated aromatic vinyl compound-conjugated diene block copolymer, a modified product of aromatic vinyl compound-conjugated diene block copolymer with silicon atom-containing polar groups, and a modified product of hydrogenated aromatic vinyl compound-conjugated diene block copolymer with silicon atom-containing polar groups.

3. The glass fiber reinforced layer according to claim 1, wherein the glass fiber is glass cloth.

4. The glass fiber reinforced layer according to claim 3, wherein the ratio of the thickness of the glass fiber reinforced layer to the thickness of the glass cloth is 1 to 5 times.

5. The glass fiber reinforced layer according to claim 1, wherein the absolute value of the difference between the refractive index of the glass fiber and the refractive index of the thermoplastic elastomer (E) is 0.07 or less.

6. The glass fiber reinforced layer according to claim 1, wherein the glass fiber reinforced layer is a constituent layer of a flexible element.

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