JP5423387B2 - Sheet-like prepreg and manufacturing method thereof - Google Patents

Description

The present invention relates to a carbon fiber prepreg which is an intermediate base material for producing a fiber-reinforced composite material and a method for producing the same. More specifically, the mass content of the thermosetting resin constituting the carbon fiber prepreg (hereinafter, resin mass content) is low, and further, the mass per unit area of the thermosetting resin (hereinafter, resin basis weight) varies. The present invention relates to a small sheet-like carbon fiber prepreg (sheet-like prepreg) and a method for producing the same.

  Carbon fiber prepregs are widely used in sports and leisure applications as intermediate materials for molded products such as golf shafts, fishing rods, badminton shafts and tennis racket frames. The purpose is mainly to improve the performance and weight of the product to be obtained. In recent years, it has been desired to further reduce the weight by using a golf shaft, a fishing rod or the like.

  For this purpose, prepregs having a low resin mass content have been developed. For example, in Patent Document 1, a prepreg having a resin mass content of 13 to 32% is exemplified as a general description, and in Patent Document 2, a prepreg having a fiber mass content of 90% or more is described as a general description. Although illustrated, no specific method for obtaining such a prepreg is disclosed.

A resin film for prepreg having a low resin basis weight is disclosed in Patent Document 3. However, the resin film and the sheet-like carbon fiber are simply combined, and the resin mass content is 10% or less by a conventional method, and the mass per unit area of the carbon fiber (hereinafter also referred to as fiber basis weight) 100 to 150 g / Even if an m ² prepreg is to be prepared, it is difficult to secure adhesiveness (hereinafter referred to as tackiness) on both surfaces of the prepreg due to insufficient amount of resin, and the prepreg from the release paper placed on the prepreg due to lack of tackiness. There was a problem that peeled off.

In order to prevent this, the amount of resin inside the reinforcing fiber is reduced to increase the amount of resin on both surfaces, that is, even if a method of maintaining the tackiness of both surfaces by deteriorating the impregnation property is applied, Along with deterioration, there is a problem that the reinforcing fiber bundle inside the prepreg burns and becomes a cracking defect of the prepreg, so it is difficult to produce a carbon fiber prepreg having a low resin mass content of 100 to 150 g / m ² per unit area. Yes, even if a resin having a low resin mass content was obtained, quality stability could not be expected.

JP-A-8-290514 JP 2003-012837 A JP 2005-264146 A

  In order to manufacture a prepreg having a low resin mass content, a sheet-like carbon fiber (generically including a carbon fiber bundle) may be used by using a resin film in which a resin is coated on a release paper. ) When manufacturing a prepreg (sheet-like prepreg), by placing a resin film on both surfaces of the carbon fiber and using a release paper having an optimal impregnation condition and an optimal release force, Finding a method for stably producing a prepreg having a low resin mass content, which is not only difficult to peel, but also cannot be realized by conventional techniques, and that produces a prepreg with a low resin mass content by that method. Is an issue.

  That is, an object of the present invention is to obtain a sheet-like prepreg having a low resin mass content with good quality and good productivity, and to ensure tackiness on both sides of the prepreg necessary for winding around a round cylinder during molding. An object of the present invention is to provide a sheet-like prepreg having a good resin mass content and a low quality.

This invention for solving the said subject is a sheet-like prepreg which has carbon fiber and a thermosetting resin, Comprising: This carbon fiber is unidirectional so that a fiber basis weight may be 100-250 g / m < ² >. The thermosetting resin is present on at least both surfaces of the sheet-like prepreg, and the resin mass content of the thermosetting resin in the sheet-like prepreg is 6 to 10%, and the following: A sheet-like prepreg characterized in that the tack value of both surfaces of the sheet-like prepreg described in the above is 1.0 N or more.

  The sheet-like prepreg preferably has a resin mass content variation per unit area of the thermosetting resin described below of 5.0% or less.

  The sheet-like prepreg is further provided with a release paper on at least one surface thereof, and the sheet-like prepreg and the release paper have a peeling resistance of 0.3 to 2.5 N / 25 mm. More preferably.

Such sheet-like prepreg was oriented in one direction, the basis weight of the carbon fibers of 100 to 250 g / m ^2, after sandwiched by the resin film consisting of the both surfaces are coated with the thermosetting resin on a release paper It can be produced by a method for producing a sheet-like prepreg comprising a step of pressing a heated metal roll group consisting of at least one and pressing at a heating temperature of 90 to 130 ° C. and a linear pressure of 1000 to 60000 N / m.

Further, when such a sheet-like prepreg, using a reverse roll coater having a metering roll and a coating roll and the backup roll is coated with the thermosetting resin onto the release paper to produce a resin film, the coating the roll speed C, and the resin film speed when the F, 0 <by using a resin film obtained as satisfy the C / F <1.0, it is possible to more favorably produced.

  According to the present invention, although the prepreg has a low resin mass content, the resin basis weight variation is small, the tackiness on both sides of the prepreg necessary for winding is ensured, and a sheet-like prepreg with good quality can be obtained.

It is a schematic perspective view of the support used for the measurement of the peeling strength of a sheet-like prepreg. It is the schematic which shows the state which is measuring the peeling strength of a sheet-like prepreg. It is a schematic side view of the apparatus for manufacturing the carbon fiber prepreg which concerns on one embodiment of this invention.

The present invention is a sheet-like prepreg comprising carbon fibers and a thermosetting resin, and the carbon fibers are oriented in one direction so that the mass per unit area is 100 to 250 g / m ² , The thermosetting resin is present at least on both surfaces of the sheet-like prepreg, the resin mass content of the thermosetting resin in the sheet-like prepreg is 6 to 10%, and tack on both surfaces of the prepreg A sheet-shaped prepreg having a value of 1.0 N or more.

  As the carbon fiber used in the present invention, polyacrylonitrile (hereinafter referred to as PAN) system, pitch system, and the like are known, and any of them may be used, or a mixture of them may be used. good. The carbon fiber used has a tensile elastic modulus of 200 to 900 GPa determined according to JIS R 7608 (2007). However, since the resin mass content is low, a carbon fiber in the range of 450 to 700 GPa is used. For example, in applications such as fishing rods that require a high elastic modulus, the mechanical characteristics can be set high, which is advantageous as a material to be used.

Moreover, as for the carbon fiber in this invention, 1000-72000 are preferable and, as for the number of filaments per fiber bundle, 3000-12000 are more preferable. Furthermore, in the sheet-like prepreg of the present invention, the carbon fiber mass per unit area in the prepreg, that is, the carbon fiber basis weight is 100 to 250 g / m ² .

  Moreover, the carbon fiber bundle used in the present invention is formed in a sheet shape aligned in one direction.

  As the thermosetting resin used in the present invention, any resin usually used for the production of carbon fiber prepregs can be used. For example, epoxy resin, unsaturated polyester resin, vinyl ester resin, phenol resin, cyanate Examples include ester resins. Among these, an epoxy resin having a curing temperature of 150 ° C. or less is preferable from the viewpoint of handleability and product mechanical properties, and a thermoplastic resin can be blended in a part of the composition as a modifier.

  The thermosetting resin is preferably a thermosetting resin having a minimum viscosity of 0.1 to 300 poise. If the viscosity is lower than this range, it may be difficult to apply with a desired coating thickness, that is, a desired resin basis weight. Conversely, if the viscosity is too high, a uniform coating thickness with a metalling roll or a coating roll may occur. It may be difficult to adjust. Here, the resin viscosity is measured using a dynamic viscoelasticity method, and as a measuring device, for example, an RDA-II type device manufactured by Rheometrics, Inc. can be used. The minimum viscosity in the present invention means that when the temperature is raised from room temperature, the resin viscosity is once lowered and then the viscosity is increased, but this means the minimum viscosity value in this profile. Moreover, the temperature which shows this minimum viscosity is defined as minimum viscosity temperature. These characteristics are measured using such an apparatus under the conditions of vibration: 3.14 radians / second, heating rate: 1.5 ° C./min, parallel plate with a radius of 25 mm, and gap: 1.0 mm. .

In the sheet-like prepreg of the present invention, a resin film produced so that the mass content of the thermosetting resin in the sheet-like prepreg is 6 to 10% is used by being sandwiched from both surfaces of a sheet made of carbon fiber. By adopting such means, it is necessary that the thermosetting resin be present on both surfaces of the prepreg. When manufacturing the sheet-shaped prepreg by applying the above-mentioned thermosetting resin only to one surface of the sheet made of carbon fibers aligned in one direction, the resin basis weight is large and there are few problems in the resin film manufacturing process. When manufacturing a sheet-like prepreg, the mass content of the thermosetting resin is insufficient, so it is difficult to reach the opposite surface of the sheet-like prepreg with the thermosetting resin softened by impregnation. A sheet-like prepreg of good quality in which tackiness on both sides of the sheet-like prepreg necessary at times is ensured cannot be obtained.

  The tackiness of the sheet-like prepreg of the present invention is determined by subjecting PICMA Tack Tester II manufactured by Toyo Seiki Seisakusho Co., Ltd. It is obtained by pressing a cover glass of 18 mm × 18 mm onto a prepreg with a load of 0.4 kgf for 5 seconds, peeling it off at a speed of 30 mm / min, and measuring the maximum value of the resistance force when peeling off. What is used for a microscope measurement can be used for a cover glass, for example, MICRO COVER GLASS 18mmx18mm, thickness: 0.12-0.17mm (made by MATSUNAMI) can use it conveniently.

  When the tack value measured by such a method is 1.0 N or more, a prepreg having good handleability without peeling when wound around a mandrel is obtained.

  In the sheet-like prepreg of the present invention, the variation in the resin mass content of the thermosetting resin is preferably 5.0% or less. If this variation exceeds 5.0%, the width of the sheet prepreg and the uniformity in the longitudinal direction are slightly inferior. For example, local peeling when wound around a cylinder, unevenness of the molded product after curing, etc. The problem may occur. By making this variation 5.0% or less, it is possible to obtain a molded body that maintains good winding properties and has no uneven thickness.

  The resin mass content rate of a thermosetting resin here is measured by the method prescribed | regulated to JISK7071 (1988).

  By measuring the resin mass content of the sample taken from the sheet-shaped prepreg width direction by such a method, subtracting the minimum value from the maximum value, and determining the range, the variation in the resin mass content is obtained. Ask. The strip-shaped sample used here is a sheet-like prepreg cut from the end into a strip of width 40 mm × length 250 mm without gaps in the width direction (the width direction is aligned in one direction of the prepreg). It means a direction perpendicular to the fiber direction).

  In addition, as the release paper of the sheet-like prepreg of the present invention, a silicone-coated prepreg process paper can be used, and the composition of the silicone used as a release agent, the amount thereof, and the conditions such as drying after coating and heat treatment are adjusted. By doing so, the release force (peeling resistance) can be adjusted to a desired value. As release paper used for this invention, it is preferable that peeling resistance of a sheet-like prepreg and release paper shall be 0.3-2.5N / 25mm, and 0.4-2.4N / 25mm is more preferable. That is, if the peeling resistance between the sheet-like prepreg and the release paper is small, the adhesion between the sheet-like prepreg and the release paper is weak. May cause poor quality such as peeling off and floating, and in a more severe case, peeling may occur completely, and the form may not be maintained depending on the handling method. On the other hand, if the peeling resistance is too large, the sheet-like prepreg and the release paper are too strongly bonded, so it is not easy to peel off the sheet-like prepreg and the release paper during molding, and the release paper may be damaged in some cases. In some cases, the production efficiency during the molding process may be reduced.

  In addition, the sheet-like prepreg of the present invention is a single layer or a laminated base material obtained by laminating it, and is heated and cured to suppress the variation in weight and thickness, and the carbon fiber reinforced with good quality and quality. Composite materials can be manufactured. In obtaining the laminated base material, the sheet-like prepreg may be arranged to form a round cylinder or the like so as to include a structure in which the orientation directions of the respective carbon fibers of the sheet-like prepregs adjacent to each other are intersected. The carbon fiber reinforced composite material produced using the sheet-like prepreg of the present invention can be formed into various shapes such as a flat plate shape and a cylindrical shape by a known molding method.

  For example, the sheet-like prepreg of the present invention is arranged in a cylindrical shape of 0 °, and the other prepreg is formed in a round cylinder shape arranged in a so-called bias layer, and preferably the resin mass content of the prepreg forming the bias layer is The prepreg is 10% or more with respect to the resin mass content of the 0 ° layer prepreg, and more preferably the difference in the resin mass content is 10% to 25%. If the difference in resin content between the prepreg of the bias layer and the prepreg of the 0 ° layer is less than 10%, the weight reduction effect is excellent, but the quality and composite characteristics of the molded product may be slightly inferior. When combined with a prepreg having a difference exceeding 25%, the effect of reducing the weight is hardly exhibited.

  In the sheet-like prepreg of the present invention, a low-weight resin film is sandwiched from both surfaces of the carbon fiber oriented in one direction, and then pressed into a heated metal roll group consisting of at least one, and a heating temperature of 90 to The process of pressurizing at 130 ° C. and linear pressure of 1000 to 60000 N / m can be preferably produced by the method.

When manufacturing a sheet-like prepreg having a low resin mass content as in the present invention, when impregnating a carbon fiber with a thermosetting resin, if the processing temperature and the impregnation pressure are too high, the absolute resin mass content Due to the shortage, the surface resin that adheres the release paper and the sheet-like prepreg will excessively impregnate the inside of the sheet-like prepreg, resulting in poor adhesion between the release paper and the sheet-like prepreg, and during the molding process There is a possibility of peeling. On the other hand, if the processing temperature and the impregnation pressure are too low, the transfer of the thermosetting resin becomes insufficient, which may cause impregnation failure on the surface of the sheet-like prepreg. From such a viewpoint, the sheet-like prepreg of the present invention is heated at 90 to 130 ° C. and heated at 1000 to 60000 N / m in a state where the sheet-like prepreg is heated. Generation | occurrence | production of peeling and generation | occurrence | production of impregnation defect can be suppressed, and a sheet-like prepreg with favorable quality can be manufactured suitably. More preferably, the heating temperature is in the range of 100 to 120 ° C. and the pressurizing condition is 12000 to 48000 N / m.

  The sheet-like prepreg produced by such a method has a tack value of 1.0 N or more on both surfaces, which causes poor quality such as voids in the molded product when the sheet-like prepreg is attached to each other or wound around a mandrel. It is possible to suppress the connected local float. In addition, since the tack value on the release surface side of the release paper is 1.0 N or more, it is sufficiently adhered to the release paper that holds the prepreg, and the peeling between the sheet-like prepreg and the release paper is suppressed during storage and transportation. There are advantages.

  The resin film to be used is preferably a thermosetting resin (hereinafter sometimes simply referred to as “resin”) on a release paper using a reverse roll coater provided with a metering roll, a coating roll, and a backup roll. When the coating roll speed is C and the resin film speed is F, 0 <C / F <1.0 is satisfied.

As conditions for manufacturing the resin film, it is preferable that the ratios of the coating roll speed C, the backup roll speed B, and the resin film speed F are respectively in the following relationship.
0 <C / F <1.0 (1) hereafter expressed as C / F ratio 0.9 ≦ F / B ≦ 1.0 (2) hereafter expressed as F / B ratio .

Further, the C / F ratio is more preferably in the following relationship.
0 <C / F ≦ 0.5 (3).

  By setting the C / F to less than 1.0, more preferably 0.5 or less, the resin can be applied while effectively stretching the resin on the release paper as compared to normal C / F = 1.0. As a result, unevenness of application of the resin, that is, spotted spots can be reduced.

Further, the speed M of the metering roll and the coating roll speed C are preferably in the following relationship.
0.5 ≦ M / C ≦ 1.2 (4) Hereinafter, it is expressed as M / C ratio.

  Furthermore, since the resin weight variation due to “runout” due to the rotation of each roll can be reduced, the range of 0.75 ≦ M / C ≦ 1.1 is more preferable.

  Here, each roll speed C, B, M is a peripheral speed of each roll. Moreover, the resin film speed F is the traveling speed of the resin film (= the traveling speed of the release paper).

  In addition, in order to realize the above relationship, a reverse roll coater is used to apply a resin to the release paper to form a resin film, and then suck it by suctioning the resin film under reduced pressure before being wound by a winder. It is preferable to apply the resin while stretching the resin as compared with a normal transfer state while gripping. By obtaining a resin film by such a method, it is possible to reduce the uneven application of the resin.

  The present invention will be described below with reference to examples.

(1) Material A. Carbon fiber M60JB-6K (tensile modulus: 588 GPa, fineness: 0.206 g / m, number of filaments: 6000) manufactured by Toray Industries, Inc. was used as the carbon fiber.

B. Resin (thermosetting resin, curing agent, curing accelerator)
The resin was prepared in advance with the following composition, and a resin composition having a minimum viscosity of 50 poise and a minimum viscosity temperature of 120 ° C. was used. Here, the resin viscosity is RDA-II type apparatus manufactured by Rheometrix Co., Ltd., operation mode: dynamic, vibration 3.14 radians / second, heating rate: 1.5 ° C./min, plate: parallel plate (radius 25 mm ), Gap: measured under the condition of 1.0 mm. The composition of the resin used is as follows.

Bisphenol A type epoxy resin (Epicoat 828, registered trademark, manufactured by Japan Epoxy Resin Co., Ltd.): 20 parts by mass Bisphenol A type epoxy resin (Epicoat 1001, registered trademark, manufactured by Japan Epoxy Resin Co., Ltd.): 30 parts by mass Phenol Novolak Type epoxy resin (Epicoat 154, registered trademark, manufactured by Japan Epoxy Resins Co., Ltd.): 50 parts by mass Polyvinyl formal (Vinylec K, trade name, manufactured by Chisso Corporation): 10 parts by mass 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU99, model number, manufactured by Hodogaya Chemical Co., Ltd.): 10 parts by mass.

C. Release paper Several types of release paper with different release forces are produced by applying a known method that adjusts the release properties of the release paper with respect to the substrate type, coating agent type, coating agent adhesion amount, and heat treatment amount. did. As shown below, four types of release paper samples were prepared, prepregs were actually made of the above materials, and the release force was measured.

Release paper type Release force with prepreg (N / 25mm)
Release paper A 2.6
Release paper B 2.4
Release paper C 0.4
Release paper D 0.2.

D. Resin film (1) B. Using Preparation resin at a reverse coater, so that the resin mass per unit area is 8 g / ^{m 2} and ^{16g / m 2 (1) C} . A resin film was prepared by coating the release paper with a width of 1000 mm.

(2) Sheet-like prepreg manufacturing method FIG. 3: has shown an example of the method of manufacturing a carbon fiber prepreg. A plurality of carbon fiber bundles 13 drawn out from a plurality of carbon fiber bundle packages 12 are drawn in a sheet form in parallel with each other via the aligning rolls 14 and 15 and the comb 16, so that the carbon fibers It is in the form of a sheet 17.

  With respect to the carbon fiber sheet 17, an upper resin film 18 drawn out from the upper resin film roll body 21 is disposed on the upper surface side of the carbon fiber sheet 17 via the introduction rolls 19 and 20, and the lower resin film 18. The lower resin film 22 drawn out from the roll body 28 of the resin film is disposed on the lower surface side of the carbon fiber sheet 17 through the introduction rolls 19 and 20.

  In this way, the carbon fiber sheet 17 sandwiched between the resin films 18 and 22 from both sides is heated by the heater 23 and the resin applied to the resin film is heated and softened, and is nipped by the impregnating rolls 24 and 25 to be added. By being pressed, the resin is impregnated in the carbon fiber sheet 17. The carbon fiber sheet 17 impregnated with the resin is wound up and collected as a roll body 30 at the position of the take-up rolls 26 and 27, and the upper release paper 29 after the resin is transferred to the carbon fiber sheet 17 side. The carbon fiber sheet 17 impregnated with the resin is wound up as a roll body 32 as a carbon fiber prepreg 31. In this embodiment, the lower release film 22 is also wound together with the carbon fiber prepreg 32 and functions as a release material when the carbon fiber prepreg 32 is unwound and used for molding a composite material.

  In such a production method, (1) A. On one or both surfaces of a sheet obtained by aligning carbon fibers of 1000 mm in one direction with a width of 1000 mm. The resin film was pressed and held in contact with a heated metal roll group, so that the carbon fiber was impregnated with a thermosetting resin to produce a sheet-like prepreg.

(3) Evaluation items and measurement method Mass per unit area; g / m ²
The sheet-like prepreg of (2) is cut into a strip of width 40 mm × length 250 mm from the end without gaps in the width direction, and when a release paper is included, it is removed as a sample, weighed with a balance, and prepreg width direction 25 The prepreg mass per 1 m ² was measured from the point prepreg mass, and the average value was obtained. Here, the width direction refers to a direction perpendicular to the fiber direction aligned in one direction of the sheet-like prepreg.

B. Resin mass content:%
From the strip-shaped sample, the resin mass content was calculated by the method of JIS K7071 (1988). The resin mass content variation was expressed by subtracting the minimum from the maximum resin mass content in the 25-point sample to obtain a range.

C. Tack value; N
The tack value is 18 mm x 18 mm cover using PICMA Tack Tester II manufactured by Toyo Seiki Seisakusho after exposure for 15-30 minutes in a measurement environment of temperature 24 ± 2 ° C and humidity 50 ± 5% RH. The glass was pressure-bonded to the prepreg with a load of 0.4 kgf for 5 seconds, peeled off at a speed of 30 mm / min, and determined by measuring the maximum resistance value at the time of peeling. As the cover glass, MICRO COVER GLASS 18 mm × 18 mm, thickness: 0.12 to 0.17 mm (manufactured by MATSANAMI) was used.

D. Peeling resistance between sheet prepreg and release paper; N / 25mm
(2) sheet-like prepreg and (1) C.I. The peel strength of the release paper was measured as follows.

  That is, the sheet-like prepreg was cut into strips having a width of 25 mm and a length of 300 mm with the release paper and the direction of the carbon fiber as the length direction to obtain a test piece. Next, as shown in FIG. 1, the test piece 1 was bent using a double-sided adhesive tape (for example, a double-sided tape T4000 manufactured by Sony Chemical Co., Ltd., width 50 mm) having a size capable of covering the entire test piece. Was attached to a stainless steel support 2 with a release paper facing outward. Next, as shown in FIG. 2, the support 2 is attached to the lower chuck 4 (fixed) of the tensile tester, and the peeled end of the release paper 1b that has been peeled off about 10 mm from the prepreg 1a is attached to the clip 5 and the metal. It is attached to the upper chuck 7 (movable) via the wire 6 and pulled from the prepreg 1a by pulling the release paper 1b at a pulling speed of 100 mm / min in an atmosphere of 23 ° C. and 50% RH. Recorded. Then, from the chart until peeling is completed, excluding 1 minute at the beginning of peeling and 1 minute at the end of peeling, the top of the load peak is read from the highest five points and the bottom of the load valley is read from the lower five points Then, a simple average value of the loads at these 10 points was obtained and defined as peel strength. As the tensile tester, an appropriate material tester of a type in which the load measurement error does not exceed ± 1% and the crosshead moving speed can be kept constant was used. As such a material testing machine, for example, a universal type tensile testing machine such as Tensilon UTM-4L manufactured by Toyo Baldwin can be used.

(4) Confirmation method of resin-containing layer in prepreg layer (observation of cross-sectional resin coating state)
The sample was cut into a size of 10 mm × 10 mm at a position 500 mm from the end of the sheet-like prepreg.

  Next, the cross section in the thickness direction of the sheet-like prepreg was observed with a microscope having a magnification of 100 times in a direction in which the fiber cross section was visible. In the sheet-like prepreg cross section, a portion where both the thermosetting resin as the matrix resin and the carbon fiber are present and a portion where only the carbon fiber is exposed can be observed. The fixed sample is observed with a reflection optical microscope and taken as a black and white photograph. At this time, the portion where the matrix resin and the carbon fiber are present is bright, and the portion where only the carbon fiber is exposed is dark and is photographed. Next, the photograph taken was binarized. There are various methods of binarization. For example, it can be performed by using a scanner connected to a personal computer and capturing black and white photographs at a resolution of 200 dpi. Although it does not specifically limit as a scanner, For example, EPSON GT-7000S etc. can be used. A histogram of a photographic image is displayed on the image processing software and binarized by the mode method, and the dark part including only the carbon fiber and the bright part including both the matrix resin and the carbon fiber can be separated.

  By this method, the resin coating state and the impregnation state in the prepreg cross section were confirmed by observing the bright and dark parts of the prepreg cross section. When this bright part is divided into 10 equal parts in the thickness direction in the thickness direction, the outermost part of the both thicknesses (the part that covers 20% of the entire top and bottom) is present as “a prepreg with resin on both sides” “A prepreg having a resin layer only on one surface” was defined as a surface having no bright portion on one surface and existing on the opposite surface.

Example 1
With a reverse roll coater with conditions set to M / C ratio = 0.8 and C / F = 0.5, a resin film coated on release paper B so that the coated resin weight per unit area is 8 g / m ² is obtained per unit area. It is sandwiched from both surfaces of a sheet made of carbon fibers aligned in one direction so as to be 150 g / m ² , passed through a hot plate and a metal nip roll heated to 110 ° C. with the above impregnation apparatus, and a linear pressure of 15000 N / After pressurizing with m and cooling to 25 ° C., the upper release paper was peeled off, covered with a polyethylene cover film, wound up, and a sheet-like prepreg A was obtained. For sheet-like prepreg A, the sheet-like prepreg basis weight, resin content, sheet-like prepreg surface (polyethylene cover side) and back surface (release paper side) tack value, peel resistance, cross-sectional resin coating state As shown in Table 1, it was possible to obtain a sheet-like prepreg having good quality and good handleability during molding operations.

Sheet prepreg A
Prepreg weight per unit: 165 g / m ²
Average resin mass content: 9.0%
Resin mass content variation: 3.2%
Surface tack value: 1.2N
Back tack value: 1.2N
Peel resistance: 2.4 N / 0.25 mm
Cross-sectional resin coating state: Present on both surfaces in the prepreg cross-sectional direction.

(Example 2)
A sheet-like prepreg B having good quality and good handleability during molding operations could be obtained in the same manner as in Example 1 except that a resin film obtained by applying a resin to release paper C was used.

Sheet prepreg B
Prepreg weight per unit: 164 g / m ²
Average resin mass content: 8.8%
Resin mass content variation: 4.2%
Surface tack value: 1.2N
Back tack value: 1.3N
Peel resistance: 0.4N / 0.25mm
Cross-sectional resin coating state: Present on both surfaces in the prepreg cross-sectional direction.

(Example 3)
A sheet-like prepreg C was obtained in the same manner as in Example 1 except that a resin film produced so that the resin mass content variation was 5.5% was used. Although the quality was good, local peeling occurred during the molding operation, and it could not be said that good handleability was obtained.

Sheet prepreg C
Prepreg weight per unit: 164 g / m ²
Resin mass content average: 9.3%
Resin mass content variation: 5.5%
Surface tack value: 1.1 N
Back tack value: 1.2N
Peel resistance: 2.4 N / 0.25 mm
Cross-sectional resin coating state: Present on both surfaces in the prepreg cross-sectional direction.

(Examples 4 and 5)
Sheet-like prepregs D and E were obtained in the same manner as in Example 1 except that resin films obtained by applying resin to release papers A and D were used. When the prepreg D was molded, the release paper was somewhat difficult to peel off, and with the prepreg F, local peeling occurred and the handleability was slightly inferior, but it was acceptable at the time of molding.

(Examples 6 to 9)
Sheet-like prepregs F, G, H, and I were obtained in the same manner as in Example 1 except that the heating temperature was changed to 90 ° C. or 130 ° C. and the pressure condition was changed to 1000 N / m or 60000 N / m. As shown in Table 1, a sheet-like prepreg having good quality and good handleability during molding could be obtained.

(Comparative Example 1)
The resin film applied to the release paper B so that the resin mass is 16 g / m ² is sandwiched from one surface (lower side) of the carbon fiber sheet aligned in one direction, and the other surface (upper side) ) A sheet-like prepreg was obtained in the same manner as in Example 1 except that the release paper B to which no resin was applied was sandwiched. As a result, the tack value on the surface side was 0.0 N, and the resin coating on the surface could not be confirmed by observing the cross-section resin coating state, and the surface of the sheet-like prepreg was fluffy with carbon fibers and could not be molded.

(Comparative Example 2)
The resin film applied to the release paper B so that the resin mass is 16 g / m ² is sandwiched from one surface (upper side) of the carbon fiber sheet aligned in one direction, and the other surface (lower side). Although it tried to obtain a sheet-like prepreg by the same method as Comparative Example 1 except that the release paper B to which the resin was not applied was further sandwiched, the prepreg was wound after passing through the impregnation portion by heating and pressurization. During the processing up to this point, peeling occurred between the release paper and the sheet-like prepreg, and processing could not be performed.

(Comparative Examples 3-6)
As shown in Table 2, production of a sheet-shaped prepreg was attempted in the same manner as in Example 1 except that the heating temperature was changed to 80 ° C. or 140 ° C. and the pressing condition was changed to 900 N / m or 60100 N / m. . In Comparative Examples 3 and 5, since the resin was not partially transferred, a prepreg having no resin on the surface was obtained. On the other hand, in Comparative Examples 4 and 6, a prepreg inferior in tack was obtained because the resin soaked significantly.

(Examples 10 and 11)
A prepreg J was prepared using the same resin and carbon fiber as the prepreg A of Example 1 for prepreg molding, with an average fiber mass content of 75%.

  When the prepreg A was arranged in the 0 ° direction and the prepreg J was arranged in the 90 ° direction to form a cylinder, a molded product of good quality was obtained (Example 10). Further, molding was carried out in the same manner as in Example 10 except that 90 ° -direction prepreg A was used. However, although the surface quality and mechanical properties were slightly inferior to those in Example 10, the surface quality and mechanical properties were generally good. Goods were obtained.

1: Test piece (prepreg material)
2: Test piece support 3: Double-sided tape 4a: Unidirectional prepreg 4b: Release paper 5: Test piece (prepreg material)
6: Test piece support 7: Double-sided tape 8: Lower chuck 9: Clip 10: Metal wire 11: Upper chuck 12: Carbon fiber bundle package 13: Carbon fiber bundle 14: Alignment roll 15: Alignment roll 16 : Comb 17: Carbon fiber sheet 18: Upper resin film 19: Introduction roll 20: Introduction roll 21: Roll body of upper resin film 22: Lower resin film 23: Heater 24: Impregnation roll 25: Impregnation roll 26: Pull Take roll 27: Take roll 28: Lower resin film roll 29: Upper release paper 30: Upper release paper roll 31: Carbon fiber prepreg 32: Carbon fiber prepreg roll

Claims (7)

A sheet-like prepreg comprising carbon fibers and a thermosetting resin, wherein the carbon fibers are oriented in one direction so that the mass per unit area is 100 to 250 g / m ^2, and the thermosetting The resin is present at least on both surfaces of the sheet-like prepreg, and the resin mass content of the thermosetting resin in the sheet-like prepreg is 6 to 10%, and is measured by the method described in the specification. A sheet-like prepreg characterized by having a tack value of 1.0 N or more on both surfaces of the sheet-like prepreg. The sheet-like prepreg according to claim 1, wherein the variation in the resin mass content per unit area of the thermosetting resin measured by the method described in the specification is 5.0% or less. The sheet-like prepreg is further provided with release paper on at least one surface thereof, and the peeling resistance between the sheet-like prepreg and the release paper is 0.3 to 2.5 N / 25 mm. The sheet-like prepreg described in 1. The sheet-like prepreg according to any one of claims 1 to 3, wherein the carbon fiber used has a tensile elastic modulus of 450 to 700 GPa determined according to JIS R 7608 (2007). A carbon fiber reinforced composite material obtained by curing the sheet-like prepreg according to any one of claims 1 to 4 or a laminated base material obtained by laminating the sheet prepreg. It is a manufacturing method of the sheet-like prepreg in any one of Claims 1-4 , Comprising: Carbon fiber with a fabric weight of 100-250 g / m < ² > orientated in one direction is the said thermosetting resin from the both surfaces. Including a step of pressing at a heating temperature of 90 to 130 ° C. and a linear pressure of 1000 to 60000 N / m after being sandwiched between resin films formed on release paper , Sheet-like prepreg manufacturing method. Using a reverse roll coater having a metering roll and a coating roll and a backup roll, wherein upon the application to the resin film the thermosetting resin on a release paper, the coating roll speed C, the resin film speed the when the F, 0 <satisfy C / F <1.0, the sheet-like prepreg method according to claim 6.

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