SMC manufacturing method

Abstract

Provided is a useful improvement in a CF-SMC manufacturing method in which a continuous carbon fiber bundle is partially divided and used. This method for producing an SMC comprises: (i) a step for pulling out from a package a continuous carbon fiber bundle (10) having a single fiber number NK, said continuous carbon fiber bundle (10) being partially divided into n sub-bundles in advance; (ii) cutting the continuous carbon fiber bundle (10) pulled out of the package with a rotary cutter (234) to form a chopped carbon fiber bundle (20); (iii) depositing the chopped carbon fiber bundle (20) on a carrier film (41) traveling below the rotary cutter (234) to form a carbon fiber stack (30), and fragmenting the carbon fiber stack (30) by bringing at least a portion of the chopped carbon fiber bundle before being deposited on the carrier film (41) into contact with a rotating body, the single fiber number distribution of the chopped carbon cellulose in the carbon fiber stack (30) is different from that when the fragmentation processing is not performed.

Description

[0001] This application is a divisional application of the invention patent application with the application date of January 14, 2021, application number 202180009443.5, and invention name “Method for manufacturing SMC”. Technical Field

[0002] The present invention relates to a method for producing SMC (sheet molding compound), and more particularly to a method for producing SMC using carbon fiber (CF), namely, CF-SMC.

[0003] This application claims priority based on international application PCT / JP2020 / 001851 filed on January 21, 2020, and Japanese Patent Application No. 2020-047205 filed in Japan on March 18, 2020, the contents of which are cited herein. Background Art

[0004] In recent years, CFRP (carbon fiber reinforced plastic), a composite material composed of carbon fiber and resin, has been widely used in parts of various transportation equipment such as aircraft, automobiles, and ships, as well as sporting goods and leisure products.

[0005] Some CFRP products are formed from CF-SMC by compression molding.

[0006] CF-SMC is a type of carbon fiber prepreg, and has a structure in which a stack of chopped carbon fiber bundles (also called "chopped carbon fiber bundles", "chopped carbon fiber strands", etc.) is impregnated with a thermosetting resin composition.

[0007] The strength of CFRP increases as it is reinforced with a carbon fiber bundle having a smaller number of single fibers, but the production cost increases as the number of single fibers in the carbon fiber bundle decreases (smaller tow size) (Patent Document 1).

[0008] It has been proposed to add a step of partially splitting the continuous carbon fiber bundle wound from a bobbin before cutting it, to a method for producing SMC that continuously performs steps from cutting of the continuous carbon fiber bundle to impregnation of the carbon fiber layer with resin (Patent Document 2).

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: U.S. Patent Application Publication No. 2012 / 0213997

[0012] Patent Document 2: International Publication No. 2017 / 221655 Summary of the invention

[0013] Technical problem to be solved by the invention

[0014] It is considered that SMC capable of obtaining a high-strength CFRP molded product can be manufactured at low cost by adopting a technology of partially splitting a continuous carbon fiber bundle having a large number of single fibers classified into a normal bundle or a large bundle.

[0015] Since various adjustments are required in the process of partially dividing the continuous carbon fiber bundle, it is possible to improve the overall manufacturing efficiency by separating this process from the subsequent processes in the production of SMC.

[0016] The present invention was completed during the process of research by the inventors of the present invention based on the above-mentioned idea, and its main purpose is to provide a useful improvement in the CF-SMC production technology including a method for producing CF-SMC using a continuous carbon fiber bundle by partially splitting it.

[0017] In this specification, problems that can be solved by each embodiment of the present invention are disclosed explicitly or implicitly.

[0018] Means for solving technical problems

[0019] One aspect of the present invention relates to a method for manufacturing a sheet molding compound.

[0020] The method for manufacturing a sheet molding compound according to a preferred embodiment of the present invention includes the following aspects, but is not limited thereto.

[0021] [a1] A method for manufacturing a sheet molding compound, comprising the following steps:

[0022] (i) pulling out a continuous carbon fiber bundle having a single fiber number NK which is preliminarily partially divided into n sub-bundles from a package; (ii) cutting the continuous carbon fiber bundle pulled out from the package with a rotary cutter to form a chopped carbon fiber bundle; (iii) stacking the chopped carbon fiber bundle on a carrier film traveling below the rotary cutter to form a carbon fiber pile; and performing a fragmentation treatment in which at least a portion of the chopped carbon fiber bundle before being stacked on the carrier film contacts a rotating body to be fragmented.

[0023] [a2] The method for producing a sheet molding compound according to [a1], wherein the continuous carbon fiber bundle is wound into the package so that no gaps are formed between the sub-bundles.

[0024] [a3] The method for producing a sheet molding compound according to [a1] or [a2], wherein the continuous carbon fiber bundle is wound in the package so that adjacent sub-bundles overlap each other.

[0025] [a4] The method for producing a sheet molding compound as described in any one of [a1] to [a3], wherein, in the continuous carbon fiber bundle wound in the package, the total width is smaller than the sum of the widths of the sub-bundles.

[0026] [a5] The method for producing a sheet molding compound as described in any one of [a1] to [a4], wherein the single fiber number NK of the continuous carbon fiber bundle is 12K or more.

[0027] [a6] The method for manufacturing a sheet molding compound as described in any one of [a1] to [a5], wherein the rotating body is a pin roller having a rotation axis parallel to the rotation axis direction of the rotary cutter.

[0028] [a7] A method for manufacturing a sheet molding compound as described in any one of [a1] to [a6], wherein a fragmentation processing device is used in the fragmentation processing, and the fragmentation processing device includes a first pin roller and a second pin roller, each having a rotation axis parallel to the rotation axis direction of the rotary cutter, and the sum of the maximum radius of the first pin roller and the maximum radius of the second pin roller is greater than the distance between the rotation axes of the first pin roller and the second pin roller.

[0029] [a8] A method for producing a sheet molding compound as described in any one of [a1] to [a7], wherein the content of carbon fiber bundles having a single fiber number exceeding 0.5K in the carbon fiber stack is greater than 99 wt%.

[0030] [a9] A method for producing a sheet molding compound as described in any one of [a1] to [a8], wherein the number of chopped carbon fiber bundles having a single fiber number greater than {(N / n) + 0.5}K contained in the unit weight of the carbon fiber stack is reduced through the fragmentation treatment.

[0031] [a10] The method for producing a sheet molding compound as described in any one of [a1] to [a9], wherein the package is a square end package.

[0032] [a11] The method for producing a sheet molding compound according to [a10], wherein the winding ratio in the package is not an integer.

[0033] [a12] The method for producing a sheet molding compound as described in [a10] or [a11], wherein the decimal point of the winding ratio in the package is not a multiple of any one of 1 / 2, 1 / 3, 1 / 4 and 1 / 5.

[0034] [a13] The method for producing a sheet molding compound as described in any one of [a10] to [a12], wherein the bevel angle of the start roll in the roll package is 5 to 30°, and the bevel angle of the end roll is 2 to 17°.

[0035] [a14] A method for producing a sheet molding compound as described in any one of [a1] to [a13], wherein the carbon fiber stack is pressurized together with the thermosetting resin composition in order to impregnate the carbon fiber stack with the thermosetting resin composition.

[0036] [a15] The method for producing a sheet molding compound as described in [a14], wherein at least a portion of the thermosetting resin composition is coated on the carrier film before the step (iii).

[0037] Another aspect of the present invention relates to a carbon fiber package.

[0038] The carbon fiber package according to the preferred embodiment of the present invention includes the following aspects, but is not limited thereto.

[0039] [b1] A carbon fiber package, comprising a continuous carbon fiber bundle being transversely wound around a bobbin, wherein the continuous carbon fiber bundle is partially divided into sub-bundles, and a width of the continuous carbon fiber bundle is smaller than a sum of widths of the sub-bundles.

[0040] [b2] A carbon fiber package, comprising a continuous carbon fiber bundle being transversely wound around a bobbin, wherein the continuous carbon fiber bundle is partially divided into sub-bundles and is wound around the bobbin in such a manner that the sub-bundles overlap with each other.

[0041] [b3] The carbon fiber package as described in [b1] or [b2], wherein the width of the continuous carbon fiber bundle is less than 90% of the sum of the widths of the sub-bundles.

[0042] [b4] The carbon fiber package as described in any one of [b1] to [b3], wherein the continuous carbon fiber bundle is partially divided into three or more sub-bundles.

[0043] [b5] A carbon fiber package as described in any one of [b1] to [b4], wherein the number of single fibers in the sub-bundle is less than 5K.

[0044] [b6] A carbon fiber package as described in any one of [b1] to [b5], wherein the total number of single fibers in the continuous carbon fiber bundle is greater than 12K.

[0045] [b7] The carbon fiber package as described in any one of [b1] to [b6], wherein the carbon fiber package is a square end package.

[0046] [b8] The carbon fiber package as described in [b7], wherein the winding ratio is not an integer.

[0047] [b9] The carbon fiber package as described in [b8], wherein the decimal point of the winding ratio is not a multiple of any one of 1 / 2, 1 / 3, 1 / 4 and 1 / 5.

[0048] [b10] The carbon fiber package as described in any one of [b7] to [b9], wherein the bevel angle at the start of the roll is 5 to 30° and the bevel angle at the end of the roll is 2 to 17°.

[0049] The following [b11] and [b12] are also included in the embodiments of the present invention.

[0050] [b11] A method for producing a sheet molding compound, comprising using the carbon fiber package described in any one of [b1] to [b10].

[0051] [b12] A use of a carbon fiber package, wherein the carbon fiber package described in any one of [b1] to [b10] is used in the manufacture of a sheet molding compound.

[0052] Yet another aspect of the present invention relates to a method for manufacturing a carbon fiber package.

[0053] The method for producing a carbon fiber package according to a preferred embodiment of the present invention includes the following aspects, but is not limited thereto.

[0054] [c1] A method for manufacturing a carbon fiber package, wherein the carbon fiber package is formed by transversely winding a continuous carbon fiber bundle on a winding drum, wherein the method comprises: a splitting step of partially splitting the continuous carbon fiber bundle into sub-bundles; a winding step of winding the continuous carbon fiber bundle partially split into the sub-bundles on the winding drum; in the winding step, the continuous carbon fiber bundle is wound onto the winding drum in such a manner that the width of the continuous carbon fiber bundle is smaller than the sum of the widths of the sub-bundles.

[0055] [c2] A method for manufacturing a carbon fiber package, comprising manufacturing a fiber package formed by transversely winding a continuous carbon fiber bundle on a winding drum, wherein the method comprises: a splitting step of partially splitting the continuous carbon fiber bundle into sub-bundles; a winding step of winding the continuous carbon fiber bundle partially split into the sub-bundles on the winding drum; and in the winding step, winding the continuous carbon fiber bundle onto the winding drum in a manner such that the sub-bundles overlap with each other.

[0056] [c3] A method for manufacturing a carbon fiber package as described in [c1] or [c2], wherein, in the winding step, the continuous carbon fiber bundle is wound onto the bobbin in such a manner that the width of the continuous carbon fiber bundle is less than 90% of the sum of the widths of the sub-bundles.

[0057] [c4] A method for manufacturing a carbon fiber package as described in any one of [c1] to [c3], wherein, in the splitting step, the continuous carbon fiber bundle is partially split into three or more sub-bundles.

[0058] [c5] A method for manufacturing a carbon fiber package as described in any one of [c1] to [c4], wherein the number of single fibers in the sub-bundle is less than 5K.

[0059] [c6] A method for manufacturing a carbon fiber package as described in any one of [c1] to [c5], wherein the total number of single fibers in the continuous carbon fiber bundle is greater than 12K.

[0060] [c7] A method for manufacturing a carbon fiber package as described in any one of [c1] to [c6], wherein the fiber package is a square end package.

[0061] [c8] The method for producing a carbon fiber package as described in [c7], wherein the winding ratio is not set to an integer in the winding step.

[0062] [c9] A method for manufacturing a carbon fiber package as described in [c8], wherein, in the winding step, the decimal point of the winding ratio is not set to a multiple of any one of 1 / 2, 1 / 3, 1 / 4 and 1 / 5.

[0063] [c10] The method for manufacturing a carbon fiber package as described in any one of [c7] to [c9], wherein, in the winding step, the bevel angle of the starting roll is 5 to 30°, and the bevel angle of the ending roll is 2 to 17°.

[0064] The embodiment of the present invention further includes the following method for producing a sheet molding compound.

[0065] [d1] A method for manufacturing a sheet molding compound, comprising the following steps: (i) pulling out a continuous carbon fiber bundle from a package; (ii) cutting the continuous carbon fiber bundle pulled out from the package with a rotary cutter to form a chopped carbon fiber bundle; (iii) stacking the chopped carbon fiber bundle on a carrier film traveling below the rotary cutter to form a carbon fiber pile; and using a fragmentation processing device to fragment at least a portion of the chopped carbon fiber bundle before being stacked on the carrier film by contacting a rotating body, the fragmentation processing device comprising a first pin roller and a second pin roller, each having a rotation axis parallel to the rotation axis direction of the rotary cutter, and the sum of the maximum radius of the first pin roller and the maximum radius of the second pin roller is greater than the distance between the rotation axes of the first pin roller and the second pin roller.

[0066] [d2] The method for manufacturing a sheet molding compound as described in [d1], wherein the rotation directions of the first pin roller and the second pin roller are opposite.

[0067] [d3] The method for manufacturing a sheet molding compound as described in [d2], wherein the first pin roller rotates in such a manner that the pins on the side facing the second pin roller move from top to bottom.

[0068] [d4] The method for manufacturing a sheet molding compound as described in [d2], wherein the first pin roller rotates in such a manner that the pins on the side facing the second pin roller move from bottom to top.

[0069] [d5] The method for manufacturing a sheet molding compound as described in [d1], wherein the first pin roller and the second pin roller rotate in the same direction.

[0070] [d6] A method for producing a sheet molding compound as described in any one of [d1] to [d5], wherein the content of carbon fiber bundles having a single fiber number exceeding 0.5K in the carbon fiber stack is 99 wt% or more.

[0071] The following [d7] to [d11] are also included in the embodiments of the present invention.

[0072] [d7] A use of a fragmentation processing device, wherein the fragmentation processing device has a first pin roller and a second pin roller, which have a set of rotating shafts parallel to each other and are respectively driven to rotate, the sum of the maximum radius of the first pin roller and the maximum radius of the second pin roller is greater than the distance between the rotating shafts of the first pin roller and the second pin roller, and the fragmentation processing device is used for fragmentation processing of short-cut carbon fiber bundles.

[0073] [d8] Use of the fragmentation processing device as described in [d7], wherein the rotation directions of the first pin roller and the second pin roller are opposite.

[0074] [d9] Use of the fragmentation processing device as described in [d8], wherein the first pin roller rotates in such a manner that the pins on the side facing the second pin roller move from top to bottom.

[0075] [d10] Use of the fragmentation processing device as described in [d8], wherein the first pin roller rotates in such a manner that the pins on the side facing the second pin roller move from bottom to top.

[0076] [d11] Use of the fragmentation processing device as described in [d7], wherein the rotation directions of the first pin roller and the second pin roller are the same.

[0077] According to the present invention, there is provided a useful improvement in the CF-SMC production technology, including a method for producing CF-SMC in which a continuous carbon fiber bundle is partially split and used. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 It is a schematic diagram of a fiber package manufacturing device.

[0079] Figure 2A This is a schematic diagram showing a continuous carbon fiber bundle partially divided into five strands, and is a plan view viewed from the thickness direction.

[0080] Figure 2B 1 is a schematic diagram showing a continuous carbon fiber bundle partially divided into five strands, and is a cross-sectional view showing a cross section perpendicular to the fiber direction.

[0081] Figure 3 This is a schematic diagram showing a cross section perpendicular to the fiber direction of a continuous carbon fiber bundle which is partially split into five strands and then wound onto a bobbin.

[0082] Figure 4 It is a schematic diagram of the SMC manufacturing device.

[0083] Figure 5 is a schematic diagram of a rotary cutter.

[0084] Figure 6 is a schematic diagram of a fragmentation processing device.

[0085] Figure 7 This is a schematic diagram of a pin roller included in the fragmentation processing device.

[0086] Figure 8 It represents a part of the circumference of the pin roller when the plane is unfolded.

[0087] Fig. 9 It is a schematic diagram showing the positional relationship of two pin rollers included in the fragmentation processing device.

[0088] Fig.10 It is a histogram showing the distribution of the number of single fibers in the chopped carbon fiber bundle in the carbon fiber layer.

[0089] Fig.11 It is a histogram showing the distribution of the number of single fibers in the chopped carbon fiber bundle in the carbon fiber layer.

[0090] Fig.12 It is a histogram showing the distribution of the number of single fibers in the chopped carbon fiber bundle in the carbon fiber layer.

[0091] Fig.13 It is a histogram showing the distribution of the number of single fibers in the chopped carbon fiber bundle in the carbon fiber layer.

[0092] Fig.14 It is a histogram showing the distribution of the number of single fibers in the chopped carbon fiber bundle in the carbon fiber layer.

[0093] Fig.15 It is a plan view showing a continuous carbon fiber bundle after being partially divided into five strands.

[0094] Fig.16 This is a schematic diagram of a square-end fiber package formed by transversely winding a fiber bundle on a winding drum, viewed from a direction perpendicular to the rotation axis of the winding drum.

[0095] Fig.17 It is a schematic diagram showing an example of a rotating body of the fragmentation processing device. DETAILED DESCRIPTION

[0096] 1. SMC manufacturing method

[0097] SMC is a sheet-like carbon fiber prepreg obtained by impregnating a carbon fiber layer composed of chopped carbon fiber bundles with a thermosetting resin composition.

[0098] One embodiment of the present invention is a method for producing an SMC including the following steps (i) to (iii).

[0099] (i) A step of pulling out a continuous carbon fiber bundle having a single fiber number NK which has been partially divided into n sub-bundles in advance from a package.

[0100] (ii) A step of cutting the continuous carbon fiber bundle drawn out from the package with a rotary cutter to produce a chopped carbon fiber bundle.

[0101] (iii) A step of depositing the chopped carbon fiber bundles on a carrier film traveling below the rotary cutter to form a carbon fiber pile.

[0102] In the SMC production method of the present embodiment, a fragmentation process is further performed in which at least a part of the chopped carbon fiber bundle before being deposited on the carrier film is brought into contact with a rotating body to be fragmented.

[0103] As for the technique of impregnating the carbon fiber stack formed through the above steps (i) to (iii) with the thermosetting resin composition and the technique of increasing the adhesion of the thermosetting resin composition after the impregnation as needed, reference may be made to the prior art as appropriate.

[0104] 1.1. Continuous carbon fiber bundle

[0105] In the SMC manufacturing method of the present embodiment, a package of a continuous carbon fiber bundle prepared in advance is used. The continuous carbon fiber bundle has NK single fibers and is partially divided into n sub-bundles.

[0106] NK means N x 1000. For example, the number of single fibers in a carbon fiber bundle consisting of 3000 single fibers is 3K, and the number of single fibers in a carbon fiber bundle consisting of 12000 single fibers is 12K.

[0107] N is usually 12 or more, preferably 15 or more, but is not limited thereto, and may be, for example, 18, 24, 36, 48, or 50.

[0108] The continuous carbon fiber bundle is partially divided into n sub-bundles, in other words, the continuous carbon fiber bundle is partially divided into n. Each of the n fiber bundles formed by the n divisions is called a sub-bundle. In the continuous carbon fiber bundle partially divided into n sub-bundles, the n sub-bundles are connected to each other.

[0109] The package of the partially divided continuous carbon fiber bundle is not limited, but can be used Figure 1 The fiber package manufacturing device is shown in the conceptual diagram.

[0110] Reference Figure 1 The fiber package manufacturing device 100 includes an unwinding area 110 , a splitting area 120 , and a winding area 130 .

[0111] A continuous carbon fiber bundle 10 of single fiber number NK as a starting material is pulled out from a supply bobbin B1.

[0112] The undivided continuous carbon fiber bundle 10 pulled out from the supply bobbin B1 is first spread in the spreading area 110 .

[0113] The spreading roller 111 disposed in the spreading area 110 may be heated and may also reciprocate in the width direction of the continuous carbon fiber bundle 10 . The mechanism used therefor may refer to known techniques.

[0114] The continuous carbon fiber bundle 10 is originally flat, and its width is further expanded and its thickness is further reduced by friction with the spreading roller 111. The thickness of the continuous carbon fiber bundle 10 after passing through the spreading area 110 is not limited, but is typically 0.05 to 0.2 mm.

[0115] When the continuous carbon fiber bundle 10 is sufficiently flat at the stage of being supplied from the supply bobbin B1, the expanded region 110 may be omitted. For example, a carbon fiber bundle having a bundle width of 50 times or more the average thickness can be said to be sufficiently flat.

[0116] Next, the continuous carbon fiber bundle 10 is sent to the splitting area 120, where it is partially split.

[0117] In the dividing area 120 , a rotating blade 121 for forming a slit in the continuous carbon fiber bundle 10 and a plurality of guide rollers 123 for controlling the running speed of the continuous carbon fiber bundle 10 are provided.

[0118] The rotation axis of the rotating blade 121 is parallel to the width direction of the continuous carbon fiber bundle 10 running along the fiber direction. In order to intermittently form slits of a constant length along the fiber direction of the continuous carbon fiber bundle 10 at a certain period, a plurality of blades 122 are provided at a certain interval in the circumferential direction on the outer periphery of the rotating blade 121. The slit length and the gap length between the slits can be controlled by adjusting the running speed of the continuous carbon fiber bundle 10, the peripheral speed of the rotating blade 121, and the interval between the blades 122.

[0119] The (n-1) rotating blades 121 arranged in the width direction intermittently form slits along the fiber direction, thereby partially dividing the continuous carbon fiber bundle 10 into n parts.

[0120] The number n is not limited, but is preferably 3 or more, more preferably 5 or more, and may be 10 or more.

[0121] As an example, in Figure 2A and Figure 2B 3 shows the continuous carbon fiber bundle 10 after slits extending in the fiber direction are intermittently formed by four rotating blades 121 arranged in the width direction.

[0122] For the sake of convenience, when the fiber direction (length direction) of the continuous carbon fiber bundle 10 is set as the x direction, the width direction is set as the y direction, and the thickness direction is set as the z direction, Figure 2A is a plan view of the continuous carbon fiber bundle 10 viewed from the z direction, Figure 2B 1 shows a cross section of the continuous carbon fiber bundle 10 perpendicular to the x direction (a cross section when cut along the yz plane).

[0123] like Figure 2A As shown, a first slit row A is formed in the continuous carbon fiber bundle 10. S1 , Second slit row A S2 , the third slit row A S3 and the fourth slit column A S4 of four slit columns.

[0124] First slit row A S1 It is composed of a plurality of first slits S1 arranged in the x direction.

[0125] Second slit row A S2 It is composed of a plurality of second slits S2 arranged in the x direction.

[0126] The third slit row A S3 It is composed of a plurality of third slits S3 arranged in the x direction.

[0127] Fourth slit row A S4 It is composed of a plurality of fourth slits S4 arranged in the x direction.

[0128] Since these four slit rows are formed by different rotating blades, their positions in the y direction are different.

[0129] Slit length L S and the gap length L between the slits G It is constant within any slit column and is the same between different slit columns.

[0130] Slit length L S Relative to the slit length L S and the gap length L between the slits G The ratio of the sum S / (L S +L G ) is usually 90% or more, preferably 95% or more, and may be, for example, 99%. Therefore, as shown in FIG2(b), the continuous carbon fiber bundle 10 is divided into five sub-bundles 11 in most parts.

[0131] First slit row A S1 , Second slit row A S2 , the third slit row A S3 and the fourth slit row A S4 The positions in the y direction are set so that the widths of the five sub-bundles 11 are substantially the same. For example, when the number of single fibers in the continuous carbon fiber bundle 10 is 15K, the number of single fibers in each sub-bundle 11 is 3K±0.5K.

[0132] Slit length L S Although not limited, it is preferably longer than 25 mm, more preferably longer than 50 mm, and most preferably longer than 500 mm. This is because the interval when the continuous carbon fiber bundle 10 is cut in the subsequent process is usually more than 25 mm. S The higher the ratio of the cutting interval when the continuous carbon fiber bundle 10 is cut to form a chopped carbon fiber bundle, the more chopped carbon fiber bundles having the same or less number of single fibers as the sub-bundle 11 are generated.

[0133] Slit length L S For example, it may be more than 25 mm and less than 50 mm, more than 50 mm and less than 100 mm, more than 100 mm and less than 200 mm, more than 200 mm and less than 500 mm, more than 500 mm and less than 1000 mm, more than 1000 mm and less than 1500 mm, more than 1500 mm and less than 2000 mm, or more than 2000 mm and less than 3000 mm.

[0134] Length of gap between slits L G Although not limited to this, for example, it may be 5 to 10 mm, or may be shorter than 5 mm.

[0135] exist Figure 2A In the example shown, in the first slit row A S1 and the second slit row A S2 In the middle, the slit gap G S The positions of the second slit row A are staggered in the x direction. S2 and the third slit column A S3 Between and the third slit column A S3 and the fourth slit column A S4 The same is true between.

[0136] Thus, the gaps G between adjacent slit rows are staggered in the x direction. S The structure of the position is not necessary. In one example, Fig.15 As shown, the inter-slit gaps G can be aligned between all the slit columns. S In another example, the gaps G between the slits may be aligned between some of the slit columns. S The position of the slits is set to the position of the slits between the other part of the slits. S The positions are offset in the x direction.

[0137] About the slit length L S , the gap length between the slits L G , Slit length L S Relative to the slit length L S and the gap length L between the slits G The ratio of the sum S / (L S +L G ), and the gap between the slits G S The position of is not limited to the case where the continuous carbon fiber bundle 10 is partially divided into five sub-bundles as described above, and is also the same when the continuous carbon fiber bundle 10 is partially divided into four or less or six or more sub-bundles.

[0138] The number of single fibers of the sub-bundle formed by dividing the continuous carbon fiber bundle 10 is not related to the number n, but is preferably 5K or less, more preferably 4K or less, and most preferably 3K or less. The number of single fibers of the sub-bundle formed by dividing the continuous carbon fiber bundle 10 is not related to the number n, but is preferably greater than 0.5K, and more preferably greater than 1K. When the number of single fibers is greater than 0.5K, the linearity of the carbon fiber bundle is easily maintained, and there is a tendency that the reinforcing effect is relatively improved.

[0139] The above upper and lower limits can be arbitrarily combined. For example, the number of single fibers in the sub-bundles formed by dividing the continuous carbon fiber bundle 10 is independent of the number n, and is preferably 0.5K to 5K, more preferably 0.5K to 4K, and most preferably 1K to 3K.

[0140] Refer again Figure 1The package is completed by sending the continuous carbon fiber bundle 10 partially divided into n strands in the dividing area 120 to the winding area 130 and winding it on the winding bobbin B2.

[0141] The winding bobbin B2 is, for example, a paper tube, but is not limited thereto. When the package is used, the winding bobbin B2 can be pulled out and the continuous carbon fiber bundle can be loosened by taking it out.

[0142] When the continuous carbon fiber bundle 10 is wound, no gap is generated between the sub-bundles 11. The reason is to prevent the sub-bundles 11 from biting into each other between the portion wound first on the bobbin B2 and the portion wound thereon in an overlapping manner. By winding without generating gaps between the sub-bundles 11, it is possible to prevent the continuous carbon fiber bundle 10 from becoming tangled or broken when it is unwound by taking it out or taking it in.

[0143] When the continuous carbon fiber bundle 10 is wound onto a bobbin so as not to generate gaps between the sub-bundles 11, Figure 3 As shown, the total width W of the continuous carbon fiber bundle 10 can be made smaller than the width W of the sub-bundle. S The sum of .

[0144] Figure 3 This is a cross-sectional view when the continuous carbon fiber bundle 10 is cut perpendicularly to the fiber direction, and five sub-bundles 11 are arranged without gaps in the y direction. That is, there is no portion where adjacent sub-bundles 11 are separated from each other, and all sub-bundles 11 overlap with adjacent sub-bundles 11 at the edge.

[0145] The width of the carbon fiber bundle can be reduced by guiding the carbon fiber bundle using a guide member having a width narrower than the bundle. S When the continuous carbon fiber bundle 10 is wound onto the bobbin B2 in a state where the sum of the widths of the sub-bundles is narrow, for example, in order to guide the partially divided continuous carbon fiber bundle onto the winding bobbin, a grooved roller having a groove width narrower than the sum of the widths of the sub-bundles may be used. Alternatively, the width of the fiber bundle guide of the traverse device may be made smaller than the sum of the widths of the sub-bundles.

[0146] When the total width of the continuous carbon fiber bundle is reduced in this way, not only does the overlap between the sub-bundles occur, but also a part of the sub-bundles may be folded in the width direction. Therefore, the overlap between the sub-bundles in the continuous carbon fiber bundle wound on the winding bobbin is not limited to Figure 3 Not in the way shown, but in a variety of ways.

[0147] In order to reliably prevent the existence of gaps between the sub-bundles, the total width of the continuous carbon fiber bundle 10 when wound onto the winding bobbin is preferably 90% or less, 86% or less, and more preferably 80% or less of the sum of the widths of the sub-bundles.

[0148] The total width of the continuous carbon fiber bundle when wound on the winding bobbin is not limited, but it is preferably not narrow enough to be the same as the width of the sub-bundle. In particular, when the number of sub-bundles n is large, if the total width is too small, the winding is prone to collapse.

[0149] Typically, a traversing device (not shown) is provided in the winding area 130 .

[0150] When the continuous carbon fiber bundle 10 is traverse-wound around the winding bobbin B2, the oblique angle at the start of winding may be, for example, 5 to 30°, and the oblique angle at the end of winding may be, for example, 2 to 17°, although not limited thereto.

[0151] The winding ratio indicates how many times the bobbin rotates during one round trip of the traverse guide, and can also be called the number of windings per traverse cycle. Fig.16 In the case of the square-end fiber package exemplified, if the winding ratio is an integer, the yarn is wound at the same position of the bobbin in all traverse cycles, that is, it becomes so-called ribbon winding, and the loosening property may be deteriorated.

[0152] When the decimal point of the winding ratio is a multiple of 1 / p (p is an integer greater than 2), since the wire is wound at the same position on the bobbin in each of the p cycles, the loosening property may deteriorate as in the case where the winding ratio is an integer, especially when p is small.

[0153] Therefore, when the continuous carbon fiber bundle 10 is wound onto the winding bobbin B2, the winding ratio is usually not set to an integer, and the decimal point of the winding ratio is preferably not set to a multiple of any of 1 / 2, 1 / 3, 1 / 4 and 1 / 5.

[0154] 1.2. SMC manufacturing equipment

[0155] Figure 4 A conceptual diagram showing an SMC manufacturing facility that can be preferably used in the SMC manufacturing method of the present embodiment.

[0156] Reference Figure 4 The SMC manufacturing equipment 200 includes a first resin coating area 210, a second resin coating area 220, a cutting area 230, a stacking area 240, and an impregnation area 250. A fragmentation processing device 260 is disposed between the cutting area 230 and the stacking area 240.

[0157] In the first resin coating area 210 , a first coater 211 having a doctor blade is arranged to form a first resin layer 51 made of a thermosetting resin composition 50 on a first carrier film 41 pulled out from a roll.

[0158] In the second resin coating area 220 , a second coater 212 having a doctor blade is arranged to form a second resin layer 52 made of the same thermosetting resin composition 50 on the second carrier film 42 pulled out from the roll.

[0159] In the cutting area 230, a rotary cutter 231 is arranged for cutting the continuous carbon fiber bundle 10 pulled out from a package (or a take-out bobbin).

[0160] like Figure 5 As shown, the rotary cutter 231 has a guide roller 232, a clamping roller 233 and a cutting roller 234. A plurality of blades 235 are arranged at regular intervals on the outer periphery of the cutting roller 234, and the chopped carbon fiber bundle 20 having a certain fiber length can be continuously cut out from the continuous carbon fiber bundle 10.

[0161] Normally, a plurality of continuous carbon fiber bundles 10 are simultaneously supplied to the rotary cutter 231 while being aligned in parallel with each other in a plane parallel to the rotation axis direction of the rotary cutter 231 .

[0162] The rotation axis direction of the rotary cutter 231 is the direction of the rotation axis of the main components of the rotary cutter 231 such as the cutter roller 234. The directions of the rotation axes of the guide roller 232 and the pinch roller 233 are the same as the direction of the rotation axis of the cutter roller 234.

[0163] The deposition area 240 is arranged below the cutting area 230. The first carrier film 41 is conveyed from the first resin coating area 210 to the impregnation area 250 via the deposition area 240. When the first carrier film 41 travels in the deposition area 240, the chopped carbon fiber bundles 20 produced in the cutting area 230 are dropped and deposited on the first resin layer 51 formed on the surface of the first carrier film 41, thereby forming a carbon fiber pile 30.

[0164] A mechanism for gradually approaching the first carrier film 41 and the second carrier film 42 is arranged at the upstream portion of the impregnation area 250. The impregnation machine 251 is arranged at the main part of the impregnation area 250. The impregnation machine 251 has two upper and lower belt conveyors, and rollers for clamping and pressing the laminated body together with the conveyor belts, so that the laminated body of the carbon fiber stack 30 and the thermosetting resin composition 50 is sandwiched and conveyed by two conveyor belts from top to bottom.

[0165] like Figure 6As shown, the fragmentation processing device 260 disposed between the cutting area 230 and the stacking area 240 includes a cover 261, a guide plate 262 disposed inside the cover, and a pair of pin rollers (a first pin roller 263a and a second pin roller 263b). The first pin roller 263a and the second pin roller 263b are located below the guide plate, have substantially the same axial length, and have rotation axes parallel to each other.

[0166] In the SMC manufacturing apparatus 200 , the fragmentation processing device 260 is arranged so that the rotation axes of the first pin roller 263 a and the second pin roller 263 b are parallel to the rotation axis direction of the rotary cutter 231 .

[0167] Reference Figure 7 The first pin roller 263a has a cylinder 264a, and a plurality of pins 265a having the same shape and size are arranged on the surface of the cylinder 264a. The cylinder 264a and the pins 265a are both rigid bodies, for example, formed of metal.

[0168] The diameter of the cylinder 264a is not limited, but can be, for example, 60 mm to 150 mm.

[0169] The pin 265a extends perpendicularly to the rotation axis of the first pin roller 263a and has, for example, a cylindrical shape, although not limited thereto. The boundary between the end surface and the outer peripheral surface of the pin 265a may also be chamfered.

[0170] The diameter of the pin 265a is not limited, but may be, for example, 1 mm to 5 mm.

[0171] The length of the pin 265a, that is, the distance from the front end to the root of the pin is not limited, but can be, for example, 10 mm to 50 mm.

[0172] It is preferable that the pin 265a has a circular cross section to prevent fuzzing of the chopped carbon fiber bundle 20 processed by the fragmentation processing device 260. The pin 265a may have a conical or truncated conical shape whose diameter decreases toward the front end.

[0173] When the circumferential surface of the cylinder 264a is developed in a flat plane, it is preferred that the arrangement of the pins 265a on the circumferential surface overlap with the original arrangement when the pins 265a are shifted by 5 mm to 20 mm in the axial direction and by 4 mm to 30 mm in the circumferential direction.

[0174] For example, in Figure 7 In the case of the cylinder 264a shown in FIG. 1 , when the circumferential surface plane is unfolded, as shown in FIG. Figure 8 As shown, the pin 265a is arranged at each vertex of a regular triangle (indicated by a dotted line) filled with a plane so that one side is parallel to the axial direction. When the length of one side of the regular triangle is, for example, 5 mm, Figure 8 The arrangement of the pin 265a shown overlaps with the original arrangement when it is offset by 2.5 mm in the axial direction and by approximately 4.3 mm in the circumferential direction.

[0175] All of what has been described above with respect to the first pin roller 263 a also corresponds to the second pin roller 263 b .

[0176] Although not limited, in order to reduce the design, manufacturing and maintenance costs of the fragmentation processing device 260, including the maximum radius, cylinder diameter, shape, size, number and configuration of the pins, it is preferred to make the design and specifications of the first pin roller 263a and the second pin roller 263b consistent in as many items as possible.

[0177] In this specification, the maximum radius of the pin roller is defined as the distance from its rotation axis to the front end of the pin.

[0178] Reference Fig. 9 In the fragmentation processing device 260, the maximum radius r of the first pin roller 263a is M1 and the maximum radius r of the second pin roller 263b M2 The sum is greater than the distance d between the rotation axes of the two pin rollers 12 .

[0179] The maximum radius r of the first pin roller 263a M1 and the radius r of the cylinder 264b of the second pin roller C2 The sum can be less than the distance d between the rotation axes of the two pin rollers 12 Similarly, the maximum radius r of the second pin roller 263b is M2 and the radius r of the cylinder 264a of the first pin roller C1 The sum is also less than the distance d between the rotation axes of the two pin rollers 12 .

[0180] The first pin roller 263 a and the second pin roller 263 b are rotationally driven by a driving mechanism (not shown).

[0181] The rotation direction of the first pin roller 264a and the second pin roller 263b is not limited. Therefore, the rotation direction of the first pin roller 264a and the rotation direction of the second pin roller 263b can be the same or opposite.

[0182] When the first pin roller 264a and the second pin roller 263b rotate in opposite directions, they can rotate inward or outward. Inward rotation means that any pin roller rotates on the side facing the other pin roller in a manner that the pin moves from top to bottom. Outward rotation means the opposite, that any pin roller rotates on the side facing the other pin roller in a manner that the pin moves from bottom to top.

[0183] In other embodiments, the number of pin rollers provided in the fragmentation processing device may be one, or may be three or more.

[0184] The fragmentation processing device is not limited to the structure including the pin roller as the rotating body.

[0185] For example, Fig.17 As shown, the rotor in the fragmentation processing device may have a structure in which a pair of disks are connected by a plurality of wires or rods.

[0186] 1.3. SMC manufacturing method

[0187] The SMC manufacturing method of the present embodiment will be described by taking the case where the SMC manufacturing apparatus 200 described in 1.2. above is used as an example.

[0188] (Pulling process)

[0189] In the drawing-out step, a continuous carbon fiber bundle is drawn out from a previously prepared package of a continuous carbon fiber bundle. The number of single fibers in the continuous carbon fiber bundle is NK, and the continuous carbon fiber bundle is partially divided into n sub-bundles in advance.

[0190] In this step, the bobbin package may be mounted on the bobbin and the continuous carbon fiber bundle may be pulled out by external extraction, or the continuous carbon fiber bundle may be pulled out from the package with the bobbin removed by internal extraction.

[0191] As described above, when making a package, the continuous carbon fiber bundle is wound onto the bobbin with adjacent sub-bundles overlapping each other. Therefore, the continuous carbon fiber bundle pulled out from the package includes portions where the sub-bundles are bonded to each other with each other partially overlapping each other.

[0192] (Cutting process)

[0193] In the cutting process, the drawn continuous carbon fiber bundle 10 is supplied to the cutting area 230 and cut one by one by the rotary cutter 231, thereby producing a chopped carbon fiber bundle 20 having a predetermined fiber length. The produced chopped carbon fiber bundle 20 falls toward the fragmentation processing device 260 provided below the rotary cutter 231.

[0194] The fiber length of the chopped carbon fiber bundle 20 is not limited, but is preferably 20 to 60 mm, for example, about 25 mm or about 50 mm.

[0195] (Fragmentation process)

[0196] As described above, the continuous carbon fiber bundle pulled out from the package includes a portion where the sub-bundles are bonded to each other in a state where they partially overlap. The chopped carbon fiber bundle produced in the cutting process includes a fiber bundle having a single fiber number greater than {(N / n)+0.5}K to a certain extent, which is produced by cutting the above-mentioned portion. The purpose of the fragmentation process is to fragment such a fiber bundle by using a fragmentation processing device to improve the single fiber number distribution of the chopped carbon fiber bundle in the carbon fiber pile formed in the stacking process described later.

[0197] In the fragmentation processing device 260, at least a part of the chopped carbon fiber bundle 20 dropped from the rotary cutter 231 contacts at least one of the first pin roller 263a and the second pin roller 263b, and is divided into a plurality of fragments by the impact thereof.

[0198] The fragmentation process is not intended for defibration. That is, the chopped carbon fiber bundle is not untied until it becomes a single fiber or a state close thereto. In a preferred example, the peripheral speed of each pin tip of the first pin roller 263a and the second pin roller 263b is set in such a manner that a fiber bundle and single fibers with a single fiber count of less than 0.5K are not generated by the fragmentation process, or even if generated, the content of the single fibers in the carbon fibers deposited on the first carrier film 41 is less than 1% by weight.

[0199] (Resin coating process)

[0200] In the resin coating process, a first resin layer 51 composed of a thermosetting resin composition 50 is formed on a first carrier film 41 pulled out from a roller using a first coating machine 211, and a second resin layer 52 composed of the same thermosetting resin composition 50 is formed on a second carrier film 42 pulled out from another roller using a second coating machine 212.

[0201] The thermosetting resin composition 50 is a fluid paste containing a thermosetting resin as a main component, a tackifier and a curing agent, and additives such as a low shrinkage agent, a filler, and a flame retardant as needed.

[0202] Typical examples of the thermosetting resin are epoxy resin, vinyl ester resin, unsaturated polyester resin, polyimide resin, maleimide resin and phenol resin, and two or more selected from these resins may be mixed and used.

[0203] Preferred thermosetting resins are epoxy resins, vinyl ester resins, and unsaturated polyester resins because of their excellent adhesion to carbon fibers.

[0204] For the specific compounding composition of the thermosetting resin composition, reference may be made to the prior art as appropriate.

[0205] (Stacking process)

[0206] In the stacking process, the chopped carbon fiber bundles 20 processed by the fragmentation processing device 260 fall onto the first carrier film 41 transported below the fragmentation processing device 260. The fallen chopped carbon fiber bundles 20 are stacked on the first resin layer 51 formed on the surface of the first carrier film 41 to form a carbon fiber stack 30.

[0207] (Impregnation process)

[0208] The first carrier film 41 carrying the carbon fiber stack 30 deposited on the first resin layer 51 is bonded to the second carrier film 42 with the surface on which the second resin layer 52 is to be formed facing downward while being conveyed to the impregnation machine 251 .

[0209] The carbon fiber stack 30 is impregnated with the thermosetting resin composition 50 by pressurizing the laminate formed by bonding using the impregnation machine 251 .

[0210] After the impregnation process is completed, the impregnated carbon fiber stack 30 is wound on a bobbin by the first carrier film 41 and the second carrier film 42, and becomes an SMC product through a maturation process. In the maturation process, the thermosetting resin composition 50 becomes highly viscous due to the added thickener and becomes a semi-cured state.

[0211] 2. Experimental Results

[0212] The following describes the results of experiments conducted by the present inventors.

[0213] Experiment 1

[0214] (Preparation of partially split continuous carbon fiber bundle)

[0215] As the starting material, a flat continuous carbon fiber bundle (TR50S15L produced by Mitsubishi Chemical Corporation) with a single fiber count of 15K, an initial width of 8 mm, and a thickness of 0.1 mm was prepared. The continuous carbon fiber bundle was partially divided into five 1.6 mm wide sub-bundles by using a splitter with four rotating blades to form four slits with a length of 1000 mm and a gap length of 5 mm between the slits. The position of the gap in the fiber direction between the slits was the same in all the slit rows.

[0216] After being partially split, the continuous carbon fiber bundle was wound on a paper bobbin with a diameter of 82 mm and a length of 280 mm at a traverse length of 254 mm to produce a square-end package. The total width of the continuous carbon fiber bundle during winding was set to 6 mm or less by adjusting the width of the guide that guides the fiber bundle.

[0217] (Production of carbon fiber stack)

[0218] In addition to not having a fragmentation processing device, use the same Figure 4 The SMC manufacturing apparatus having the same structure as the SMC manufacturing apparatus shown in the figure produces a carbon fiber pile from the continuous carbon fiber bundle having a single fiber count of 15K which is prepared in the above steps and partially divided into five sub-bundles.

[0219] A plurality of continuous carbon fiber bundles were simultaneously supplied to a rotary cutter in a state of being arranged in parallel at equal intervals, and cut every 25.4 mm.

[0220] The chopped carbon fiber bundles fell onto the carrier film which was not coated with the thermosetting resin composition and was traveling at a linear speed of 5 m / min below the rotary cutter. The fallen chopped carbon fiber bundles accumulated on the carrier film to form a carbon fiber pile.

[0221] (Determination of single fiber number distribution)

[0222] An approximately 21 cm×30 cm region deposited near the center line of the carrier film was selected from the carbon fiber stack produced in the above-described steps, and the weight of all chopped carbon fiber bundles (300 or more) contained in the region was measured. Fig.10 The single fiber number distribution of the chopped carbon fiber bundle in the carbon fiber layer is obtained by converting the measured weight into the single fiber number.

[0223] In the produced carbon fiber pile, the content of carbon fiber bundles having a single fiber number exceeding 0.5K is 99.9% by weight or more.

[0224] Experiment 2

[0225] The carbon fiber stack was produced using the same SMC manufacturing apparatus as used in Experiment 1 except that a fragmentation processing device was provided, and its single fiber number distribution was measured in the same manner as in Experiment 1. The production procedure of the carbon fiber stack was the same as in Experiment 1 except that the chopped carbon fiber bundles were fragmented using a fragmentation processing device before being deposited on the carrier film.

[0226] Structure and function of fragmentation processing device Figure 4 The SMC manufacturing devices shown have the same structure. Both pin rollers are made of metal and have the same structure. The diameter and length of the pins arranged on the cylindrical surface of each pin roller are 3 mm and 20 mm respectively.

[0227] When the cylindrical circumferential surface plane of each pin roller is unfolded, the arrangement of the pins on the circumferential surface is periodic, and the arrangement overlaps with the original arrangement when it is offset by 7.5 mm in the axial direction and by 6.5 mm in the circumferential direction.

[0228] In Experiment 2, both pin rollers were rotated at a peripheral speed of 377 m / min at the pin tips.

[0229] The two pin rollers rotate in opposite directions to each other in an inwardly rotating manner. In other words, no matter which pin roller is on the side facing the other pin roller, the pin moves from top to bottom and rotates.

[0230] Fig.11 The single fiber number distribution of the chopped carbon fiber bundles in the produced carbon fiber layer is shown.

[0231] In the produced carbon fiber pile, the content of carbon fiber bundles having a single fiber number exceeding 0.5K is 99.9% by weight or more.

[0232] 2.3 Experiment 3

[0233] The carbon fiber stack was produced in the same manner as in Experiment 2 except that the two pin rollers were rotated in opposite directions. The outward rotation means that any pin roller was rotated so that the pins moved upward from the bottom on the side facing the other pin roller.

[0234] Fig.12 The distribution of the number of single fibers in the chopped carbon fiber bundles in the produced carbon fiber layer is shown.

[0235] The content of carbon fiber bundles having a single fiber count exceeding 0.5K in the produced carbon fiber pile is 99.9% by weight or more.

[0236] Experiment 4

[0237] A carbon fiber stack was produced in the same manner as in Experiment 2 except that the two pin rollers were rotated in the same direction.

[0238] exist Fig.13 : shows the single fiber number distribution of the chopped carbon fiber bundle in the produced carbon fiber stack.

[0239] The content of carbon fiber bundles having a single fiber count exceeding 0.5K in the produced carbon fiber pile is 99.9% by weight or more.

[0240] Experiment 5

[0241] When one of the two pin rollers was removed, it was likely to contact the pin roller on which the chopped carbon fiber bundles had fallen from the rotary cutter, and the position of the remaining pin roller was shifted.

[0242] Fig.14 The single fiber number distribution of the chopped carbon fiber bundles in the produced carbon fiber layer is shown.

[0243] The content of carbon fiber bundles having a single fiber count exceeding 0.5K in the produced carbon fiber pile is 99.9% by weight or more.

[0244] Experiment 6

[0245] A flat continuous carbon fiber bundle with 15,000 single fibers (15K), an initial width of 8 mm, and a thickness of 0.1 mm was prepared, partially split, and wound on a paper bobbin with a diameter of 82 mm and a length of 280 mm with a traverse length of 254 mm to produce a square-end fiber package. No widening with an unfolding roll was performed.

[0246] The continuous carbon fiber bundle was partially split using a splitter with four rotating blades. The continuous carbon fiber bundle was partially split into five interconnected sub-bundles of 1.6 mm width by forming four slit rows with a slit length of 1000 mm and a gap length of 5 mm between the slits. The position of the gap between the slits in the fiber direction was the same for all slit rows.

[0247] During the winding process, the bevel angle of the starting roll was 9.9°, the bevel angle of the ending roll was 5°, the winding ratio was set to 11.30, and the winding amount was 5.0 kg.

[0248] By adjusting the groove width of the grooved roller through which the continuous carbon fiber bundle passes after the splitting process, the bobbin was pulled out from a fiber package produced by setting the width of the continuous carbon fiber bundle wound on the bobbin to 6 mm, which is 75% of the total width of the sub-bundles, and the continuous carbon fiber bundle was pulled out from the inside, and no particular problems were found.

[0249] In contrast, in a fiber package produced in the same manner except that the width of the continuous carbon fiber bundle wound on the bobbin was set to 8 mm, which is the same as the sum of the widths of the sub-bundles, the frequency of entanglement when the bobbin was pulled out and the continuous carbon fiber was pulled out from the inside was relatively high.

[0250] The present invention has been described above based on specific embodiments, but each embodiment is presented as an example and does not limit the scope of the present invention. Each embodiment described in this specification can be modified in various ways without departing from the scope of the present invention, and can be combined with the features described by other embodiments within the scope of implementation.

[0251] Description of Reference Numerals

[0252] 10: Continuous carbon fiber bundle;

[0253] 11: sub-beam;

[0254] 20: chopped carbon fiber bundles;

[0255] 100: Fiber package manufacturing device;

[0256] 110: Expand area;

[0257] 120: segmentation area;

[0258] 130: winding area;

[0259] 200: SMC manufacturing device;

[0260] 210: first resin coating area;

[0261] 220: second resin coating area;

[0262] 230: Cut off area;

[0263] 240: accumulation area;

[0264] 250: Impregnation area;

[0265] 260: fragmentation processing device;

[0266] 300D: roll diameter;

[0267] 300D B : bobbin diameter;

[0268] 300L T : traverse length;

[0269] 300W: Width of fiber bundle;

[0270] 310: Fiber package;

[0271] 312: fiber bundle;

[0272] 314: bobbin;

[0273] θ 300 :bevel;

[0274] 410: Rotation axis;

[0275] 412: disc;

[0276] 414: Line or rod.

Claims

1. A carbon fiber package, comprising a continuous carbon fiber bundle traversingly wound on a bobbin, wherein: The continuous carbon fiber bundle is partially divided into sub-bundles, The width of the continuous carbon fiber bundle is smaller than the sum of the widths of the sub-bundles.

2. A carbon fiber package, comprising a continuous carbon fiber bundle traversingly wound on a bobbin, wherein: The continuous carbon fiber bundle is partially divided into sub-bundles, The sub-bundles are wound around the bobbin in such a manner that they overlap with each other.

3. The carbon fiber package according to claim 1 or 2, wherein: The width of the continuous carbon fiber bundle is less than 90% of the sum of the widths of the sub-bundles.

4. The carbon fiber package according to any one of claims 1 to 3, wherein The continuous carbon fiber bundle is partially divided into three or more sub-bundles.

5. The carbon fiber package according to any one of claims 1 to 4, wherein The number of single fibers in the sub-bundle is less than 5K.

6. The carbon fiber package according to any one of claims 1 to 5, wherein The total number of single fibers in the continuous carbon fiber bundle is greater than 12K.

7. The carbon fiber package according to any one of claims 1 to 6, wherein The carbon fiber package is a square-end package.

8. The carbon fiber package according to claim 7, wherein: The winding ratio is not an integer.

9. The carbon fiber package according to claim 8, wherein: The decimal point of the winding ratio is not a multiple of 1 / 2, 1 / 3, 1 / 4 and 1 / 5.

10. The carbon fiber package according to any one of claims 7 to 9, wherein The bevel angle of the start roll is 5 to 30 degrees, and the bevel angle of the end roll is 2 to 17 degrees.

11. A method for manufacturing a sheet molding compound, wherein: The carbon fiber package according to any one of claims 1 to 10 is used.

12. Use of a carbon fiber package, wherein: In the production of a sheet molding compound, the carbon fiber package according to any one of claims 1 to 10 is used.

13. A method for producing a carbon fiber package, wherein the carbon fiber package is formed by traversing and winding a continuous carbon fiber bundle on a bobbin, wherein: have: A splitting step of partially splitting the continuous carbon fiber bundle into sub-bundles; a winding step of winding the continuous carbon fiber bundle partially divided into the sub-bundles on the bobbin; In the winding step, the continuous carbon fiber bundle is wound around the bobbin such that the width of the continuous carbon fiber bundle is smaller than the sum of the widths of the sub-bundles.

14. A method for producing a carbon fiber package, comprising producing a fiber package formed by traversing and winding a continuous carbon fiber bundle around a bobbin, wherein: have: A splitting step of partially splitting the continuous carbon fiber bundle into the sub-bundles; a winding step of winding the continuous carbon fiber bundle partially divided into the sub-bundles on the bobbin; In the winding step, the continuous carbon fiber bundle is wound around the bobbin so that the sub-bundles overlap each other.

15. The method for producing a carbon fiber package according to claim 13 or 14, wherein: In the winding step, the continuous carbon fiber bundle is wound around the bobbin so that the width of the continuous carbon fiber bundle is 90% or less of the sum of the widths of the sub-bundles.

16. The method for producing a carbon fiber package according to any one of claims 13 to 15, wherein: In the splitting step, the continuous carbon fiber bundle is partially split into three or more sub-bundles.

17. The method for producing a carbon fiber package according to any one of claims 13 to 16, wherein: The number of single fibers in the sub-bundle is less than 5K.

18. The method for producing a carbon fiber package according to any one of claims 13 to 17, wherein: The total number of single fibers in the continuous carbon fiber bundle is 12K or more.

19. The method for producing a carbon fiber package according to any one of claims 13 to 18, wherein: The fiber package is a square-ended package.

20. The method for producing a carbon fiber package according to claim 19, wherein: In the winding step, the winding ratio is not set to an integer.

21. The method for producing a carbon fiber package according to claim 20, wherein: In the winding step, the decimal point of the winding ratio is not set to a multiple of any one of 1 / 2, 1 / 3, 1 / 4 and 1 / 5.

22. The method for producing a carbon fiber package according to any one of claims 19 to 21, wherein: In the winding process, the bevel angle of the start winding is 5 to 30 degrees, and the bevel angle of the end winding is 2 to 17 degrees.

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