Unidirectional fiber-reinforced resin and laminate

Abstract

To provide a unidirectional fiber-reinforced resin capable of achieving both surface smoothness and mechanical strength at a high level while achieving thinning.SOLUTION: A unidirectional fiber-reinforced resin obtained by impregnating a glass fiber roving aligned in one direction with a resin, wherein the glass fiber roving is composed of a plurality of glass filaments having a flat cross-sectional shape along a direction orthogonal to a longitudinal direction and a flatness ratio (major axis / minor axis) of 1.5 or more, the glass-fiber roving has a yarn count of 500tex or more and 7500tex or less, and when the glass-fiber roving is fibrillated into monofilaments in a state in which both ends of the glass-fiber roving stretched horizontally are fixed so as to be separated horizontally by 2m, a yarn length difference between a glass filament extending horizontally and a glass filament hanging most downward is 10mm or more and 100mm or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a unidirectional fiber reinforced resin obtained by impregnating glass fiber rovings aligned in one direction with a resin, and a laminate using the unidirectional fiber reinforced resin. [Background technology]

[0002] Conventionally, fiber-reinforced resins, which are composites of glass fibers and matrix resins, have been used in various fields such as automotive components, electrical and electronic parts, etc. Known examples of fiber-reinforced resins include unidirectional fiber-reinforced resins obtained by impregnating glass fiber rovings aligned in one direction with resin, and laminates obtained by laminating multiple unidirectional fiber-reinforced resins.

[0003] For example, Patent Document 1 below discloses a material in which continuous reinforcing fibers arranged in one direction are impregnated with a polyamide resin. Patent Document 1 describes that the cross section perpendicular to the longitudinal direction of the continuous reinforcing fibers is non-circular with an aspect ratio, expressed as major axis (D2) / minor axis (D1), of 1.5 or more. Patent Document 1 also describes that glass fibers are used as the continuous reinforcing fibers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 203893 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a growing demand for thinner walls in fields such as automotive components and electrical and electronic parts, and there is also a demand for even thinner unidirectional fiber reinforced resins.

[0006] However, when an attempt is made to reduce the amount of resin added to a unidirectional fiber-reinforced resin to make it thinner, the glass fibers are exposed on the surface of the unidirectional fiber-reinforced resin, which reduces the surface smoothness and impairs the appearance. On the other hand, when an attempt is made to reduce the amount of glass fiber added as well as the resin to make it thinner, sufficient mechanical strength may not be obtained.

[0007] Even with the material of Patent Document 1, when an attempt is made to make the material thinner, it is difficult to achieve high levels of both surface smoothness and mechanical strength.

[0008] An object of the present invention is to provide a unidirectional fiber reinforced resin and a laminate using the unidirectional fiber reinforced resin that can achieve high levels of surface smoothness and mechanical strength while achieving a thin film. [Means for solving the problem]

[0009] The unidirectional fiber reinforced resin according to the present invention is a unidirectional fiber reinforced resin obtained by impregnating a glass fiber roving aligned in one direction with a resin, wherein the glass fiber roving is composed of a plurality of glass filaments having a flat cross-sectional shape along a direction perpendicular to the longitudinal direction and an aspect ratio (major axis / minor axis) of 1.5 or more, the count of the glass fiber roving is 500 tex or more and 7500 tex or less, and when the glass fiber roving is stretched horizontally and both ends thereof are fixed at a distance of 2 m from each other in the horizontal direction and the glass fiber roving is defibrated to form monofilaments, the yarn length difference, which is the hanging width from the horizontally extending glass filaments to the lowest hanging glass filament, is 10 mm or more and 100 mm or less.

[0010] In the present invention, the ignition loss of the glass fiber roving is preferably 0.1% by mass or more and 1.5% by mass or less.

[0011] In the present invention, it is preferable that the glass filaments constituting the glass fiber roving have an equivalent circle diameter of 8 μm or more and 30 μm or less.

[0012] In the present invention, the number of the glass filaments constituting the glass fiber roving is preferably 1,200 or more and 6,000 or less.

[0013] In the present invention, the count of the glass fiber roving is preferably 1000 tex or more and 4800 tex or less.

[0014] In the present invention, the difference in fiber length in the glass fiber roving is preferably 20 mm or more and 70 mm or less.

[0015] In the present invention, the glass content in the unidirectional fiber reinforced resin is preferably 40% by mass or more and 90% by mass or less.

[0016] The laminate according to the present invention is characterized by comprising at least two resin layers made of the unidirectional fiber reinforced resin constructed according to the present invention.

[0017] In the present invention, the angle formed between the direction in which the glass fiber rovings in the upper resin layer are oriented and the direction in which the glass fiber rovings in the lower resin layer are 45° or more and 90° or less. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a unidirectional fiber reinforced resin and a laminate using the unidirectional fiber reinforced resin that can achieve high levels of surface smoothness and mechanical strength while achieving a thin film. [Brief explanation of the drawings]

[0019] [Figure 1] 1(a) and 1(b) are schematic diagrams for explaining a method for measuring the difference in yarn length. [Figure 2] FIG. 2 is a schematic perspective view showing an example of glass fiber roving used in producing a unidirectional fiber reinforced resin. [Figure 3] FIG. 3 is a schematic cross-sectional view showing a laminate according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Preferred embodiments will be described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. In addition, in each drawing, components having substantially the same functions may be referred to by the same reference numerals.

[0021] [Unidirectional fiber reinforced resin] The unidirectional fiber reinforced resin of the present invention is a fiber reinforced resin obtained by impregnating glass fiber rovings aligned in one direction with a resin.

[0022] The glass fiber roving is formed by bundling a plurality of glass filaments. The number of glass filaments (monofilaments) constituting the glass fiber roving is not particularly limited, but is preferably 1200 or more, more preferably 3500 or more, and preferably 6000 or less, more preferably 5500 or less. When the number of glass filaments is within the above-mentioned range, the mechanical strength of the unidirectional fiber reinforced resin can be further increased.

[0023] The glass filaments have a flat cross-sectional shape along a direction perpendicular to the longitudinal direction, and an aspect ratio (major axis / minor axis) of 1.5 or more. In this specification, "flat cross-sectional shape" means that the cross-sectional shape is flat, but a non-circular shape is preferable, an oval shape or an elliptical shape is more preferable, and an oval shape is even more preferable. Glass filaments having such a shape can be obtained by drawing molten glass from a nozzle having a flat cross-sectional shape.

[0024] In this specification, the flattening ratio can be expressed as the ratio of the longest side passing through the center of gravity in the cross section of the glass filament to the shortest side (longest side / short side), where the longest side passing through the center of gravity is the longest side and the shortest side is the shortest side.

[0025] In the present invention, by using glass filaments whose cross-sectional shape along the direction perpendicular to the longitudinal direction is flat and whose flatness ratio (long diameter / short diameter) is 1.5 or more, the short diameter of the glass filaments can be made small, thereby making it possible to reduce the thickness of the unidirectional fiber-reinforced resin.

[0026] The aspect ratio (major axis / minor axis) of the glass filaments is preferably 2.0 or more, more preferably 3.3 or more, and preferably 6.0 or less, more preferably 5.0 or less. When the aspect ratio (major axis / minor axis) of the glass filaments is equal to or greater than the above-mentioned lower limit, the unidirectional fiber reinforced resin can be made even thinner. When the aspect ratio (major axis / minor axis) of the glass filaments is equal to or less than the above-mentioned upper limit, the glass fiber roving can be made even less likely to break, and workability can be further improved.

[0027] The equivalent circle diameter of the glass filaments is preferably 8 μm or more, more preferably 10 μm or more, and preferably 30 μm or less, more preferably 24 μm or less. When the equivalent circle diameter of the glass filaments is equal to or greater than the above-mentioned lower limit, it is possible to more easily maintain a flat cross-sectional shape during production of the unidirectional fiber-reinforced resin. When the equivalent circle diameter of the glass filaments is equal to or less than the above-mentioned upper limit, it is possible to more increase the toughness of the glass filaments themselves and more effectively suppress fuzzing.

[0028] The equivalent circle diameter of the glass filament can be obtained by measuring the cross-sectional area of ​​the glass filament using an electron microscope or the like and determining the diameter of a perfect circle that has the measured area.

[0029] In the present invention, the count of the glass fiber roving is 500 tex or more and 7500 tex or less. When the count of the glass fiber roving is equal to or more than the above-mentioned lower limit, the mechanical strength of the unidirectional fiber reinforced resin can be increased. Furthermore, when the unidirectional fiber reinforced resin is molded, the glass fiber roving can be made less likely to fluff, and breakage of the glass fiber roving can be made less likely. Therefore, when the count of the glass fiber roving is equal to or more than the above-mentioned lower limit, workability can also be improved. On the other hand, when the count of the glass fiber roving is equal to or less than the above-mentioned upper limit, the unidirectional fiber reinforced resin can be made thinner. Furthermore, the glass fiber roving can be made more easily bent, and breakage of the glass filaments can be made less likely. Therefore, when the count of the glass fiber roving is equal to or less than the above-mentioned upper limit, worker safety can be increased and workability can also be improved.

[0030] The count of the glass fiber roving is preferably 1000 tex or more, more preferably 1200 tex or more, and preferably 4800 tex or less, more preferably 3000 tex or less. When the count of the glass fiber roving is within the above range, the unidirectional fiber reinforced resin can be made thinner, while the mechanical strength can be further increased and the workability can be further improved.

[0031] The count of the glass fiber roving can be adjusted by, for example, the number of glass filaments constituting the glass fiber roving or the equivalent circle diameter of the glass filaments.

[0032] In the present invention, the difference in fiber length in the glass fiber roving measured by the method described below is 10 mm or more and 100 mm or less. The method for measuring the difference in fiber length will be described below with reference to Figures 1(a) and 1(b).

[0033] First, the glass fiber roving 1 is cut to a length of 2 m or more (approximately 2 m to 2.2 m). Next, as shown in FIG. 1(a), both ends of the glass fiber roving 1 stretched in the horizontal direction x are fixed to support members 2 and 3 arranged 2 m apart in the horizontal direction x. At this time, both ends of the glass fiber roving 1 can be fixed to the support members 2 and 3 using, for example, an adhesive. The support members 2 and 3 are provided so as to face each other at the same height in the horizontal direction x, and are arranged so as to hold the glass fiber roving 1 horizontally.

[0034] Next, as shown in FIG. 1(b), the glass fiber roving 1 fixed to the support members 2 and 3 is opened to form monofilaments. Next, in the monofilament-formed state, the yarn length difference L, which is the hanging width up to the monofilament 10a that hangs down the lowest in the horizontal direction x, is measured. The yarn length difference L is the distance, in the vertical direction z perpendicular to the horizontal direction x, between the monofilament 10b extending in the horizontal direction x and the lowest part of the monofilament 10a that hangs down the lowest. In most cases, the measurement position is approximately the center in the horizontal direction x between the support members 2 and 3.

[0035] In the present invention, by having the yarn length difference in the glass fiber roving be equal to or greater than the above-mentioned lower limit, the glass fiber roving can be easily expanded in the resin that becomes the matrix when molding the unidirectional fiber reinforced resin, thereby improving impregnation into the resin that becomes the matrix. Furthermore, by having the yarn length difference in the glass fiber roving be equal to or less than the above-mentioned upper limit, loops can be made less likely to occur in the glass fiber roving, thereby improving impregnation into the resin that becomes the matrix. Therefore, by having the yarn length difference in the glass fiber roving be within the above-mentioned range, the unidirectional fiber reinforced resin can be made thinner while improving its mechanical strength.

[0036] In the present invention, the yarn tension difference in the glass fiber roving is preferably 20 mm or more, more preferably 30 mm or more, and preferably 80 mm or less, more preferably 70 mm or less. When the yarn length difference in the glass fiber roving is within the above-mentioned range, the mechanical strength can be further increased while the thickness of the unidirectional fiber reinforced resin can be reduced.

[0037] The yarn tension difference in the glass fiber roving can be adjusted, for example, by the size of the bushing used to form the glass filaments or the winding speed used to wind the glass filaments. For example, by increasing the size of the bushing, the yarn length difference between the glass filaments drawn out from the end and the glass filaments drawn out from the center can be increased. Furthermore, by increasing the winding speed, tension is applied to the glass filaments, thereby making it possible to reduce the yarn length difference. The method for adjusting the yarn tension difference in the glass fiber roving may be other methods, and is not particularly limited.

[0038] In the present invention, the ignition loss of the glass fiber roving is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and preferably 1.5% by mass or less, more preferably 1.0% by mass or less. When the ignition loss of the glass fiber roving is within the above-mentioned range, the strands of the glass fiber roving are easily spread and easily impregnated with the matrix resin, thereby making it possible to obtain a unidirectional fiber reinforced resin with higher uniformity. The ignition loss can be measured in accordance with JIS R3420 (2013).

[0039] In the unidirectional fiber-reinforced resin of the present invention, the resin impregnated into the glass fiber roving is the resin that becomes the matrix. The resin that becomes the matrix is ​​not particularly limited and can be appropriately selected depending on the molding method, and for example, a thermoplastic resin or a thermosetting resin can be used. Examples of thermoplastic resins include polyolefins such as polycarbonate and polypropylene, and polyesters such as polyamide, polyetherimide, and polyethylene terephthalate (PET). Examples of thermosetting resins include epoxy resins, phenolic resins, polyimide resins, and unsaturated polyester resins. These resins may be used alone or in combination.

[0040] In the present invention, the glass content in the unidirectional fiber reinforced resin is preferably 40% by mass or more, more preferably 50% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less. When the glass content is within the above range, the mechanical strength of the unidirectional fiber reinforced resin can be further increased.

[0041] In the present invention, the content of the resin (matrix resin) in the unidirectional fiber reinforced resin is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less. When the resin content is within the above range, the surface smoothness of the unidirectional fiber reinforced resin can be further improved.

[0042] (Method of manufacturing unidirectional fiber reinforced resin) In the method for producing a unidirectional fiber-reinforced resin of the present invention, first, a plurality of glass filaments are prepared. Specifically, glass raw materials are charged into a glass melting furnace and melted to form molten glass. After this molten glass is made homogeneous, the molten glass is drawn out from a heat-resistant nozzle attached to a bushing. The drawn molten glass is then cooled to obtain a plurality of glass filaments (monofilaments). Note that, for example, a platinum bushing can be used as the bushing.

[0043] When forming a plurality of glass filaments, the plurality of glass filaments are formed so as to have a flat cross-sectional shape and an aspect ratio (major axis / minor axis) of 1.5 or more. Specifically, by drawing molten glass from a nozzle having a flat cross-sectional shape, a plurality of glass filaments are formed so as to have a flat cross-sectional shape and an aspect ratio (major axis / minor axis) of 1.5 or more. The cross-sectional shape of the glass filaments is assumed to be a cross-sectional shape along a direction perpendicular to the longitudinal direction.

[0044] The raw material (glass raw material) for the glass filaments is not particularly limited, and for example, E glass, S glass, D glass, AR glass, etc. can be used. Among them, when E glass is used, it is inexpensive and can further increase the mechanical strength of the unidirectional fiber reinforced resin. Furthermore, when S glass is used, the mechanical strength of the unidirectional fiber reinforced resin can be further increased.

[0045] Next, a sizing agent is applied to the surfaces of the obtained plurality of glass filaments by a sizing agent application mechanism. With the sizing agent evenly applied, the plurality of glass filaments are aligned and bundled together in an amount of several hundred to several thousand. The plurality of glass filaments can be aligned and bundled together by, for example, a bundling shoe. In this way, a glass fiber roving can be formed.

[0046] The sizing agent may contain, for example, one or more thermoplastic resins selected from the group consisting of polyolefin resins such as polypropylene resin, acrylic resin, nylon resin, polyvinyl acetate, or polyphenylene sulfide resin. The sizing agent may also contain one or more thermosetting resins selected from the group consisting of polyester (unsaturated polyester) resin, epoxy resin, and polyurethane resin. The sizing agent may further contain components such as a silane coupling agent such as aminosilane, a lubricant, a nonionic surfactant, or an antistatic agent. The sizing agent may be applied in such a range that the ignition loss of the resulting glass fiber roving is, for example, 0.1% by mass or more and 1.5% by mass or less.

[0047] Next, the sizing agent is heated and dried to evaporate the water, thereby forming a coating on the surface of the glass filaments. For example, hot air drying or dielectric drying can be used as the heat drying method. Heat drying can be carried out, for example, at a temperature range of 100°C to 150°C for 1 hour to 24 hours. This allows the glass fiber roving 22 shown in FIG. 2 to be obtained.

[0048] 2, the glass fiber roving 22 obtained by the above method can be used in the form of, for example, a wound body 21. The inner peripheral side of the wound body 21 as described above may be hollow, or a core such as a bobbin may be disposed in the center of the wound body 21.

[0049] Next, glass fiber rovings are pulled out from each of the multiple wound bodies prepared in the same manner, and are passed through a spreader in a state of being arranged at equal intervals to widen the width of each glass fiber roving. At this time, the width of each glass fiber roving can be widened to, for example, 5 mm or more and 30 mm or less. The orientation direction of the glass fiber roving can be adjusted by the number of spreaders and the tension with which the glass fiber roving is pulled out.

[0050] Next, the glass fiber roving that has passed through the spreader is inserted between two upper and lower impregnation rolls. When the glass fiber roving is inserted between the impregnation rolls, resin melted by an extruder is also supplied at the same time. This allows the resin to be impregnated into the glass fiber roving in the impregnation rolls. The set temperature of the extruder can be, for example, (melting point of resin + 20)°C or higher and (melting point of resin + 80)°C or lower. The temperature of the impregnation roll can be, for example, (melting point of resin + 20)°C or higher and (melting point of resin + 80)°C or lower.

[0051] Next, the glass fiber roving that has passed through the impregnation roll is sent to a cooling roll and cooled while being wound around a core material to obtain a unidirectional fiber-reinforced resin. The temperature of the cooling roll can be, for example, below the glass transition temperature of the resin. The shape of the core material can be, for example, cylindrical.

[0052] The unidirectional fiber reinforced resin of the present invention can be used, for example, as a unidirectional fiber reinforced resin sheet. The thickness of the unidirectional fiber reinforced resin sheet can be, for example, 10 μm or more and 500 μm or less. The width of the unidirectional fiber reinforced resin sheet can be, for example, 10 mm or more and 300 mm or less.

[0053] In particular, the unidirectional fiber reinforced resin of the present invention can be suitably used as a UD tape. Specifically, the unidirectional fiber reinforced resin of the present invention can be suitably used as a UD tape for use in, for example, interior and exterior components of automobiles, building materials, aircraft materials, etc.

[0054] [Laminate] Fig. 3 is a schematic cross-sectional view showing a laminate according to one embodiment of the present invention. As shown in Fig. 3, laminate 31 is a laminate of resin layers 32. Resin layer 32 is made of the unidirectional fiber-reinforced resin of the present invention described above. Therefore, laminate 31 of this embodiment can achieve high levels of surface smoothness and mechanical strength while being thin.

[0055] In the laminate 31 of this embodiment, the angle formed between the orientation direction of the glass fiber rovings in the upper resin layer 32A and the orientation direction of the glass fiber rovings in the lower resin layer 32B is 45° or more and 90° or less. This can further increase the mechanical strength of the laminate 31. However, in the present invention, the orientation directions of the glass fiber rovings in the resin layers 32 constituting the laminate 31 may all be the same, and the orientation direction of the glass fiber rovings is not particularly limited.

[0056] The number of resin layers 32 constituting the laminate 31 is not particularly limited and can be, for example, 2 or more and 50 or less. The thickness of each resin layer 32 constituting the laminate 31 can be, for example, 10 μm or more and 500 μm or less. The thickness of the entire laminate 31 can be, for example, 20 μm or more and 25,000 μm or less.

[0057] The laminate 31 can be obtained, for example, by stacking a plurality of unidirectional fiber reinforced resin sheets. Alternatively, the laminate 31 may be obtained by stacking a plurality of unidirectional fiber reinforced resin sheets and then press-molding them.

[0058] The present invention will be described in more detail below with reference to specific examples. The present invention is not limited to the following examples, and can be practiced with appropriate modifications within the scope of the present invention.

[0059] (Examples 1 to 4 and Comparative Examples 1 to 5) First, molten glass having an E-glass composition was drawn out from a platinum bushing to obtain several hundred to several thousand glass filaments. A sizing agent was applied to the obtained several hundred to several thousand glass filaments by a roll coater method, with the sizing agent adjusted to an ignition loss of 0.4% by mass, to bundle the glass filaments to obtain a bundle. The obtained bundle was then wound around a paper tube placed on a rotating collet and dried by heating to obtain a wound glass fiber roving. In each example and comparative example, the aspect ratio of the glass filaments, as well as the count and yarn tension of the glass fiber roving, were adjusted to the values ​​shown in Table 1 below.

[0060] Next, glass fiber roving was pulled out from each of eight wound bodies produced in the same manner, and the glass fiber roving was passed through a spreader in a state of being arranged at equal intervals, so that the glass fiber roving was spread to a width of 200 mm.

[0061] Next, the glass fiber roving that had passed through the spreader was inserted between two upper and lower impregnation rolls. When the glass fiber roving was inserted between the impregnation rolls, polypropylene resin (manufactured by SunAllomer Co., Ltd., product number "PM900A") melted in an extruder was also supplied at the same time. This allowed the glass fiber roving to be impregnated with the polypropylene resin in the impregnation rolls. The extruder temperature was set to 220°C. The temperatures of both the upper and lower impregnation rolls were set to 220°C.

[0062] Next, the glass fiber roving that had passed through the impregnation roll was sent to a cooling roll and cooled while being continuously wound around a cylindrical core material for 50 m, thereby obtaining a unidirectional fiber-reinforced resin. The cooling roll temperature was set to 50°C.

[0063] In all of the Examples and Comparative Examples, the glass content in the obtained unidirectional fiber reinforced resin was 70 mass %, and the content of the matrix resin was 30 mass %.

[0064] [evaluation] (Flatness ratio and equivalent circle diameter of glass filament) First, to observe the cross section of the glass filaments, multiple glass filaments were embedded vertically in room-temperature curing resin Technovit (manufactured by Kulzer), and polished after the resin cured. Next, the cross-sectional shape of the glass filaments was observed with an optical microscope, and the lengths of the major and minor axes of the observed glass filaments were measured to calculate the aspect ratio (major axis / minor axis) and determine the arithmetic mean of the aspect ratios. The number of glass filaments was 100. The cross-sectional area of ​​the cross-sectional shape of 100 glass filaments was determined by image analysis, and the circle-equivalent diameter was calculated from the cross-sectional area.

[0065] (Glass fiber roving count) The count of the glass fiber roving was measured in accordance with JIS L 0101-1978.

[0066] (Difference in yarn tension in glass fiber roving) First, the glass fiber roving was cut to a length of 2 m or more (approximately 2 m to 2.2 m). Next, both ends of the horizontally stretched glass fiber roving were fixed with an adhesive to support members arranged 2 m apart in the horizontal direction. Next, the glass fiber roving fixed to the support members was opened to form monofilaments. Next, in the monofilamentized state, the yarn length difference, which is the hanging width to the monofilament hanging lowest in the horizontal direction, was measured.

[0067] (Surface smoothness of unidirectional fiber reinforced resin) The surface smoothness was evaluated by measuring the arithmetic mean roughness (Ra) on the surface of the unidirectional fiber reinforced resin using a stylus surface roughness measuring instrument in accordance with JIS B 0651-2001.

[0068] (average thickness of unidirectional fiber reinforced resin) The average thickness per sheet of unidirectional fiber reinforced resin was measured in accordance with JIS K 7130-1999.

[0069] (Flexural strength of unidirectional fiber reinforced resin) The unidirectional fiber-reinforced resin was cut to a predetermined length, and 20 sheets of these were stacked and loaded into a mold. The mold was heated to 220°C on a hot press to melt the resin. After the resin was melted, it was pressed at 220°C and 5 MPa using a pressing jig. The mold was then cooled to room temperature to obtain a unidirectional fiber-reinforced resin laminate. The obtained laminate was subjected to a three-point bending test using a precision universal testing machine in accordance with JIS K 7017-1999. The bending strength of the unidirectional fiber-reinforced resin laminate was measured.

[0070] The results are shown in Table 1 below.

[0071] [Table 1]

[0072] As can be seen from Table 1, the glass filaments of Examples 1 to 4 had a flat cross-sectional shape and an aspect ratio (major axis / minor axis) of 1.5 or more. In Examples 1 to 4, the count of the glass fiber roving was 500 tex or more and 7500 tex or less, and the yarn length difference in the glass fiber roving was 10 mm or more and 100 mm or less.

[0073] Furthermore, as can be seen from Table 1, the unidirectional fiber reinforced resins of Examples 1 to 4 had an arithmetic mean roughness (Ra) of 10 μm or less, an average thickness per sheet of unidirectional fiber reinforced resin of 80 μm or less, and a bending strength of 340 MPa or more.

[0074] From these results, it was confirmed that the unidirectional fiber reinforced resins of Examples 1 to 4, in which the aspect ratio (long diameter / short diameter) of the glass filaments and the count and yarn length difference of the glass fiber roving are within the above ranges, can be made thinner while achieving high levels of surface smoothness and mechanical strength.

[0075] On the other hand, in Comparative Examples 1 to 5, in which the aspect ratio (major axis / minor axis) of the glass filaments and the count and length difference of the glass fiber roving were not within the above ranges, sufficient surface smoothness and mechanical strength could not be obtained while achieving a thin film. In Comparative Examples 2 and 4, the workability was poor and a unidirectional fiber reinforced resin could not be obtained. [Explanation of symbols]

[0076] 1,22...Glass fiber roving 2, 3...Support members 10a, 10b...Monofilament 21...Rolled body 31...Laminate 32,32A,32B…Resin layer

Claims

1. A unidirectional fiber reinforced resin obtained by impregnating glass fiber rovings aligned in one direction with resin, The glass fiber roving is composed of a plurality of glass filaments each having a flat cross-sectional shape along a direction perpendicular to the longitudinal direction and an aspect ratio (major axis / minor axis) of 1.5 or more, The count of the glass fiber roving is 500 tex or more and 7500 tex or less, When the glass fiber roving is stretched in the horizontal direction and both ends thereof are fixed at a distance of 2 m in the horizontal direction, and the glass fiber roving is defibrated to form monofilaments, the difference in yarn length, which is the hanging width from the horizontally extending glass filaments to the glass filaments hanging lowest, is 40 mm or more and 100 mm or less.

2. The unidirectional fiber reinforced resin according to claim 1, wherein the glass fiber roving has an ignition loss of 0.1 mass% or more and 1.5 mass% or less.

3. The unidirectional fiber reinforced resin according to claim 1 or 2, wherein the glass filaments constituting the glass fiber roving have an equivalent circle diameter of 8 μm or more and 30 μm or less.

4. The unidirectional fiber reinforced resin according to claim 1 or 2, wherein the number of the glass filaments constituting the glass fiber roving is 1,200 or more and 6,000 or less.

5. The unidirectional fiber reinforced resin according to claim 1 or 2, wherein the count of the glass fiber roving is 1000 tex or more and 4800 tex or less.

6. The unidirectional fiber reinforced resin according to claim 1 or 2, wherein the fiber length difference in the glass fiber roving is 40 mm or more and 70 mm or less.

7. The unidirectional fiber reinforced resin according to claim 1 or 2, wherein the glass content in the unidirectional fiber reinforced resin is 40% by mass or more and 90% by mass or less.

8. A laminate comprising at least two resin layers made of the unidirectional fiber reinforced resin according to claim 1 or 2.

9. 9. The laminate according to claim 8, wherein the angle between the paralleling direction of the glass fiber rovings in the upper resin layer and the paralleling direction of the glass fiber rovings in the lower resin layer is 45° or more and 90° or less.

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