JP6445822B2 - Reinforcing fiber bundles, reinforcing fiber bundle opening device, and reinforcing fiber bundle opening method - Google Patents

Description

  The present invention relates to a reinforcing fiber bundle such as a carbon fiber bundle, a fiber opening device for a reinforcing fiber bundle, and a fiber opening method for the reinforcing fiber bundle.

  Reinforced fiber composite materials reinforced with thermosetting resin or thermoplastic resin with carbon fiber or other reinforcing fibers have excellent features such as high tensile strength, high tensile modulus, excellent heat resistance and fatigue properties. Widely used in fields such as sports, leisure, aviation and space.

  The reinforcing fibers are usually bundled into 1000 to tens of thousands with a resin called a sizing agent or the like and supplied as a reinforcing fiber bundle. This reinforcing fiber bundle is impregnated with a thermosetting resin or a thermoplastic resin, or a chopped strand formed by cutting this reinforcing fiber bundle into a certain fiber length is dispersed in a thermosetting resin or a thermoplastic resin, By curing, a desired reinforcing fiber composite material is produced.

  When manufacturing thin composite materials or composite materials with uniform physical properties, it is important to improve the resin impregnation or dispersibility by fully opening the reinforcing fiber bundle in advance. It is. On the other hand, when a high heat resistance resin having a high curing temperature or molding temperature is used as a matrix resin, a high heat resistance is also required for a sizing agent that adheres to the reinforcing fiber bundle. However, since such high heat-resistant sizing agents generally have a high molecular weight and are often solid at room temperature, the fiber bundles to which such sizing agents are attached tend to be poor in handling properties, and in particular, have good openability. Decline is a problem.

  Conventionally, as a method for opening a reinforcing fiber bundle, there has been known a fiber opening method using a fiber opening device in which a plurality of cylindrical spreader bars are arranged in parallel (Patent Document 1). In this method, the reinforcing fiber bundle is slid on the spreader bar alternately and alternately so that one of the plurality of reinforcing fiber bundles to be opened spans the top and the other lies below. By doing so, the reinforcing fiber bundle is opened. The spreader bar used in this method is cylindrical, and there is no description about devising this shape. The purpose of this method is to reduce spread of the spreader bar and to spread the reinforcing fiber bundle uniformly.

  Patent Document 2 describes a method in which a reinforcing fiber bundle provided with a sizing agent is wound around at least three bars and passed through in a tension state to be opened. Among the bars, at least one bar is a heating bar at 50 to 200 ° C. When passing through this heating bar, the sizing agent is heated and its viscosity decreases. As a result, it is described that the reinforcing fiber bundle is smoothly opened. However, there is no description about devising the shape of the bar. When a cylindrical bar is used, the reinforcing fiber bundle is not sufficiently opened.

JP 2002-30538 A JP-A-3-146735

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a fiber-spreading apparatus and a fiber-spreading method that can sufficiently open a reinforcing fiber bundle.

  The inventor has intensively studied to achieve the above object. As a result, at the time of opening the reinforcing fiber bundle, the above object can be achieved by using a plurality of opening bars and forming the shape of one or more opening bars in the latter stage in the fiber conveying direction into a substantially spindle shape. I found it. The present invention has been completed based on the above discovery.

  The present invention for achieving the above object is described below.

[1] Reinforced by comprising at least two same-diameter opening bars sequentially arranged along the conveying direction of the reinforcing fiber bundle and at least one different-diameter opening bar arranged in the subsequent stage. A fiber bundle opening device that opens the reinforcing fiber bundle by winding and conveying the fiber bundle around the same diameter opening bar and then the different diameter opening bar,
The same-diameter opening bar is an opening bar whose diameter along the axial direction is the same,
The different-diameter opening bar is a spreading bar whose diameter is gradually increased from the both axial ends toward the center,
Opening device for reinforcing fiber bundles.

  [2] The fiber opening device according to [1], wherein a diameter of the same-diameter opening bar and a maximum diameter of the different-diameter opening bar are each 10 to 200 mm.

  [3] The fiber opening device according to [1], wherein the same-diameter opening bar and / or the different-diameter opening bar are supported so as not to rotate along the axial direction thereof.

  [4] The fiber opening device according to [1], wherein the same-diameter opening bar and / or the different-diameter opening bar includes a heater therein.

  [5] The fiber opening device according to [1], wherein the surface roughness of the same-diameter opening bar and / or the different-diameter opening bar is Ra 0.2 to 0.4 μm.

  [6] The fiber opening device according to [1], wherein the reinforcing fiber bundle is a carbon fiber bundle.

  [7] The reinforcing fiber bundle spans at least two same-diameter opening bars and at least one different-diameter opening bar disposed in the subsequent stage over these upper surfaces or dives under the lower surfaces. Is a method of opening a reinforcing fiber bundle that is conveyed alternately and repeatedly, wherein the same-diameter opening bar uses an opening bar having the same diameter along the axial direction, and the different-diameter opening bar has both ends in the axial direction. A method for opening a reinforcing fiber bundle using a fiber opening bar whose diameter gradually increases from the center toward the center.

  [8] The method for opening a reinforcing fiber bundle according to [7], wherein the surface temperature of the same-diameter opening bar and / or the different-diameter opening bar is 100 to 250 ° C.

  [9] The method for opening a reinforcing fiber bundle according to [7], wherein a contact angle between the opening bar with the same diameter and / or the opening bar with a different diameter and the reinforcing fiber bundle is 30 to 180 °.

  [10] The opening of the reinforcing fiber bundle according to [7], wherein a total contact time between the opening bar with the same diameter and / or the opening bar with the different diameter and the reinforcing fiber bundle is 0.5 to 120 seconds. Fiber method.

  [11] The method for opening a reinforcing fiber bundle according to [7], wherein the reinforcing fiber bundle is brought into sliding contact with the different-diameter opening bar while applying a tension of 0.5 to 5 g / tex.

  [12] A reinforcing fiber bundle to which a sizing agent containing 60% by mass or more of a solid resin as a nonvolatile component at 25 ° C. is attached, and a width per 1000 Tex is 8 mm or more.

  In the fiber opening device and fiber opening method of the present invention, the fiber can be greatly opened without difficulty by sliding contact with the different diameter fiber opening bar under a predetermined tension. Here, since the different-diameter opening bar has a so-called spindle shape, the center part in the width direction of the reinforcing fiber bundle being opened is strongly pressed by the different-diameter opening bar, and the reinforcing fiber bundle is expanded in the width direction. . As a result, the reinforcing fiber bundle is widened and thinned.

FIG. 1 is a schematic front view showing an example of the fiber-spreading apparatus of the present invention. FIG. 2A is a side view showing an example of the same-diameter spread bar, and FIG. 2B is a side view showing an example of the different-diameter spread bar. FIG. 3 is an explanatory diagram showing the contact angle. FIG. 4A is a side view showing another example of the same-diameter heat-opening bar, and FIG. 4B is another side view showing another example of the different-diameter opening bar.

(Opening device and opening method)
Hereinafter, with reference to the drawings, an embodiment of the present invention will be described in detail.
FIG. 1 is a schematic view showing a fiber opening device 100 of the present invention. In the figure, reference numeral 2 denotes a reinforcing fiber bundle that is continuously conveyed in the direction of the arrow X by the conveying rollers 4 and 6. 8 and 10 are tension adjusting rollers, and the tension of the reinforcing fiber bundle 2 to be opened is controlled by the rollers 8 and 10.

  The reinforcing fiber bundle 2 that has passed through the tension adjusting rollers 8 and 10 then straddles the upper surface of a predetermined number (three in the figure) of the same-diameter spread bars 12a, 12b, and 12c, or dive the lower surface. It is conveyed alternately in a zigzag manner. The reinforcing fiber bundle is conveyed to some extent by the reinforcing fiber bundle being conveyed while being in contact with the same-diameter opening bar. The reinforcing fiber bundle 2 that has been opened to some extent is then transported around the outer peripheral surface of the different-diameter opening bar 14. During this conveyance, the reinforcing fiber bundle 2 is greatly opened. Although different depending on the operating conditions, the width opened by the different-diameter opening bar 14 is preferably 1.4 to 2.7 times the supply fiber bundle.

  The reinforcing fiber bundle 2 opened as described above is conveyed by the conveying roller 16, sent to the winding device 18, and wound up in a roll shape.

  FIG. 2A is a side view showing an example of the same-diameter spread bar, and FIG. 2B is a side view showing an example of the different-diameter spread bar. As shown in FIG. 2A, the shape of the same-diameter spread bar 12c is a cylindrical shape having the same diameter along the axial direction. Further, as shown in FIG. 2B, the shape of the different-diameter spread bar 14 is a so-called spindle shape in which the diameter along the axial direction gradually increases from both ends toward the center. The same-diameter opening bar and different-diameter opening bar have outer peripheral portions that are the opening portions of the reinforcing fiber bundle.

  As for the shape of the different-diameter opening bar 14, the shape of the cross section along the axis of the different-diameter opening bar 14 is preferably an arc. The radius (curvature radius) of the arc is preferably 50 to 100 mm, and more preferably 60 to 80 mm. When the radius (curvature radius) of the arc is 50 to 100 mm, it is easy to adjust the opened width of the fiber bundle to 1.4 to 2.7 times. If the radius (curvature radius) of the arc is too large, the opening efficiency tends to decrease. If the radius (curvature radius) of the arc is too small, the fiber bundle tends to be opened too much, so that the fiber bundle is divided into a plurality of fiber bundles, and so-called fiber bundle cracking is likely to occur.

  The diameter of the same-diameter opening bar 12c and the maximum diameter of the different-diameter opening bar 14 are each preferably 10 to 200 mm, more preferably 20 to 150 mm, and particularly preferably 30 to 100 mm. If the diameter is too small, the opening effect tends to decrease and fluff is likely to occur.

  Further, as shown in FIGS. 4A and 4B, guide grooves 50 and 56 may be formed in each spread bar. FIG. 4A is a side view showing another example of the same-diameter spread bar. The same-diameter opening bar 22 is cylindrical as described above, and the other end 48 is formed with a guide groove 50 cut out along the outer periphery thereof. The diameter R1 of the bottom 52 of the guide groove 50 is the same over the entire width of the guide groove. The reinforcing fiber bundle 2 is opened while being wound around the guide groove 50 and conveyed. That is, the guide groove 50 is an opening portion of the reinforcing fiber bundle. Other open bars with the same diameter may be formed in the same shape.

  FIG. 4B is a side view showing another example of the different-diameter spread bar. The different-diameter opening bar 24 has a cylindrical shape, and a guide groove 56 cut out along the outer periphery thereof is formed on the other end side 54, similarly to the same-diameter opening bar 22. The guide groove 56 is a fiber-spreading portion of the reinforcing fiber bundle, like the fiber opening bar with the same diameter.

  The bottom 58 of the guide groove 56 of the different-diameter opening bar 24 has a diameter R2 of the bottom 58 of the different-diameter opening bar 24 from the both ends 58a and 58b in the width direction of the guide groove 56 toward the center 60 in the width direction. It is formed in a so-called spindle shape that gradually increases.

  As for the shape of the bottom part 58 of the guide groove 56, it is preferable that the shape of the cross section in alignment with the cylindrical axis | shaft of the different diameter spread bar 24 is circular arc shape. The radius (curvature radius) of the arc is preferably 50 to 100 mm, and more preferably 60 to 80 mm. When the radius (curvature radius) of the arc is 50 to 100 mm, it is easy to adjust the opened width of the fiber bundle to 1.4 to 2.7 times. If the radius (curvature radius) of the arc is too large, the opening efficiency tends to decrease. If the radius (curvature radius) of the arc is too small, the fiber bundle tends to be opened too much, so that the fiber bundle is divided into a plurality of fiber bundles, and so-called fiber bundle cracking is likely to occur.

  The diameter of the opening part of the same-diameter opening bar 22 and the maximum diameter of the opening part of the different-diameter opening bar 24 are each preferably 10 to 200 mm, more preferably 20 to 150 mm, and particularly preferably 30 to 100 mm. If the diameter is too small, the opening effect tends to decrease and fluff is likely to occur.

  The same-diameter opening bar and different-diameter opening bar are preferably made of a metal or alloy such as iron, copper, or stainless steel, or an inorganic material such as ceramic or glass.

  The surface roughness (Ra) of the opening portion of the same-diameter opening bar and different-diameter opening bar is preferably 0.2 to 0.4 μm, and when made of metal or alloy, the surface is preferably chrome plated. . Generation of fluff can be suppressed by setting the roughness within the above range and performing chrome plating.

  In the present invention, the same-diameter opening bar and / or the different-diameter opening bar is preferably heated to a predetermined temperature. When the opening bar is heated to a predetermined temperature, the opening bar and the reinforcing fiber bundle come into contact with each other, whereby the reinforcing fiber bundle and the sizing agent applied to the reinforcing fiber bundle are heated and softened. Even a reinforcing fiber bundle to which an agent is attached can be effectively opened. The surface temperature of the same-diameter opening bar and the different-diameter opening bar is preferably 100 to 250 ° C, and more preferably 120 to 220 ° C. Moreover, the surface temperature of the same-diameter opening bar and the different-diameter opening bar is preferably higher than the softening temperature or flow start temperature of the sizing agent attached to the reinforcing fiber bundle, and is higher than 10 ° C. Is more preferable.

  In order to set the surface temperature of the opening part of the opening bar to a desired value, it is preferable that the same-diameter opening bar and the different-diameter opening bar include heating means. As the heating means, an electric heater, an infrared heater, a heating medium, a heating means using hot air, and the like are preferable. As a particularly preferred heating means, a method of embedding an electric heater in the same-diameter opening bar and the different-diameter opening bar can be exemplified.

  The contact angle between the same-diameter spread bars 12a, 12b, 12c and the different-diameter spread bars 14 and the reinforcing fiber bundle 2 is preferably 30 to 180 degrees, and more preferably 45 to 120 degrees. By setting this angle, the reinforcing fiber bundle is suitably opened.

  Here, as shown in FIG. 3, the contact angle is such that the reinforcing fiber bundle is separated from the opening bar 80 and the portion 84 where the reinforcing fiber bundle 82 facing the opening bar 80 starts to contact the opening bar 80. It is the central angle α of the opening bar 80 formed by the portion 86 and the axial center of the opening bar 80.

  There is no restriction | limiting in particular as a reinforcing fiber bundle which can be opened with this opening apparatus. For example, carbon fiber bundles, synthetic fiber bundles such as polyamide, inorganic fiber bundles such as glass fibers, etc. are suitably opened. The number of single fibers constituting the reinforcing fiber bundle is preferably 1000 to 100,000.

  If this fiber opening apparatus is used, even a fiber bundle to which a sizing agent is applied can be effectively opened. Since the sizing agent is applied to the fiber bundle, it can be opened while suppressing fluff. In the case of a carbon fiber bundle, the applied amount of the sizing agent is preferably 0.1 to 5.0% by mass, more preferably 0.2 to 3.0% by mass, and 0.2 to 1.0% by mass. Is more preferable. The sizing agent imparted to the carbon fiber bundle is not particularly limited. For example, known sizing agents such as epoxy resins, urethane resins, polyester resins, vinyl ester resins, polyamide resins, polyether resins, acrylic resins, polyolefin resins. And polyimide resins and modified products thereof.

  When the sizing agent applied to the reinforcing fiber bundle is a sizing agent containing 60% by mass or more of a solid resin as a nonvolatile component at 25 ° C., the heat resistance of the reinforcing fiber bundle is preferably improved. Conventionally, carbon fibers to which a sizing agent containing a large amount of a solid resin at 25 ° C. is attached have been problematic in that the opening property tends to be lowered. It can also be effectively used for fiber opening treatment of fiber bundles applied as a sizing agent.

  Next, a description will be given with reference to a case where a reinforcing fiber bundle is opened using the opening device shown in FIG.

  First, as shown in FIG. 1, the reinforcing fiber bundle 2 is wound around the rollers 8, 10, the same-diameter opening bars 12 a, 12 b, 12 c and the different-diameter opening bars 14. Next, the tension adjusting rollers 8 and 10 adjust the tension of the reinforcing fiber bundle 2 conveyed while sliding the different-diameter opening bar 14 to 0.5 to 5 g / tex. Since a predetermined tension is applied to the reinforcing fiber bundle 2, there is a pressing force between the same-diameter heat-opening bars 12 a, 12 b, 12 c and the different-diameter heat-opening bars 14 and the reinforcing fiber bundle 2. Arise. As a result, the reinforcing fiber bundle 2 is opened.

  Furthermore, preferably, the surface temperatures of the same-diameter opening bars 12a, 12b, 12c and the different-diameter opening bars 14 are adjusted to 100 to 250 ° C. By heating the opening bar, the reinforcing fiber bundle 2 is heated, the viscosity of the sizing agent applied to the reinforcing fiber bundle 2 is lowered, and the reinforcing fiber bundle is opened more effectively.

  The total contact time of the same-diameter opening bars 12a, 12b, 12c and the different-diameter opening bars 14 and the reinforcing fiber bundle 2 is not particularly limited, but is preferably 0.5 to 120 seconds, and 2 to 50 seconds. More preferred.

  By operating as described above, the raw reinforcing fiber bundle 2 is normally opened with a width of 1.4 to 2.7 times.

  In addition, in the said example, although the three same-diameter opening bar | burr was arrange | positioned, it is not restricted to this, Two or more, Preferably 2-5 can be arrange | positioned. Furthermore, although one dissimilar diameter opening bar is disposed, the present invention is not limited to this, and one or more, preferably 1 to 3, can be disposed.

  Furthermore, in the above example, the same-diameter opening bars and different-diameter opening bars (which are referred to as opening bars) are disposed so as not to rotate along their axes. It may be attached and the opening bar may be rotatably arranged along its axis.

  When the fiber opening method of the present invention is used, even a fiber bundle to which a high heat-resistant sizing agent is attached can be effectively opened.

(Reinforced fiber bundle)
The reinforcing fiber bundle of the present invention is a reinforcing fiber bundle to which a sizing agent containing 60% by mass or more of a solid resin as a nonvolatile component at 25 ° C. is attached, and is a reinforcing fiber bundle having a width per 1000 Tex of 8 mm or more. A reinforcing fiber bundle to which a sizing agent containing a solid resin as a non-volatile component at 25% by mass or more, that is, a sizing agent as a main agent, is excellent in heat resistance. Furthermore, by setting the width per 1000 Tex to 8 mm or more, a reinforcing fiber bundle excellent in the impregnation property of the matrix resin or the dispersibility in the matrix resin is obtained.

  The adhesion amount of the sizing agent of the reinforcing fiber bundle is preferably 0.1 to 5.0% by mass, more preferably 0.2 to 3.0% by mass, and still more preferably 0.2 to 1.0% by mass. When the amount of the sizing agent is within such a range, it becomes easy to achieve both adhesion to the matrix resin and heat resistance. If the adhesion amount of the sizing agent is too small, the adhesion to the matrix resin tends to be lowered, and if the adhesion amount of the sizing agent is too much, the heat resistance tends to be lowered.

  Known sizing agents can be used as described above. Among these sizing agents, a sizing agent having high heat resistance is preferable. The sizing agent having high heat resistance is a sizing agent containing 60% by mass or more of a solid resin as a nonvolatile component at 25 ° C., and preferably a sizing agent containing 80% by mass or more of a solid resin at 25 ° C. The main component of the non-volatile component of the sizing agent is preferably a resin having a softening temperature or a flow start temperature of 50 to 300 ° C, and more preferably a resin having a temperature of 100 to 200 ° C. The main component of the nonvolatile component of the sizing agent is preferably a resin having a decomposition temperature of 300 to 500 ° C. The molecular weight is 3000 or more, preferably 3000 to 20000.

  The width | variety per 1000 Tex of the reinforcing fiber bundle of this invention is 8 mm or more, Preferably it is 8-30 mm, More preferably, it is 10-25 mm, More preferably, it is 13-20 mm. The thickness of the reinforcing fiber bundle is preferably 0.01 to 0.15 mm, more preferably 0.02 to 0.12 mm, from the viewpoint of impregnation of the matrix resin or dispersibility into the matrix resin. More preferably, it is 0.05-0.1 mm. In addition, it is preferable that the flatness ratio, which is the ratio of the width to the thickness of the reinforcing fiber bundle, is in the range of 70 to 500, from the viewpoint of compatibility between the handling ability of the reinforcing fiber bundle, the impregnation property, and the dispersibility. 400 is more preferable, and 250 to 350 is even more preferable.

  A chopped strand is manufactured by cutting the reinforcing fiber bundle into a predetermined length. 3-15 mm is preferable and, as for the length of a chopped strand, 5-10 mm is more preferable. Chopped strands having a length of less than 3 mm tend to reduce the handling properties of the chopped strands because the bulk density of the chopped strands becomes small. Chopped strands of more than 15 mm tend to have poor supply stability when the chopped strands are supplied to an injection molding machine, an extruder for producing pellets, or the like.

  As a cutting method, a rotary cutter such as a roving cutter or a commonly used cutter such as a guillotine cutter can be appropriately used.

  The reinforcing fiber bundle of the present invention obtained as described above can be used for various known applications as various thermosetting resins or thermoplastic resin reinforcing materials. When reinforcing fiber bundles are used as chopped strands, they are kneaded with a matrix resin to form a compound, or the chopped strands and the matrix resin are directly fed to a hopper of a molding machine and kneaded and molded. Can be manufactured.

  As the thermosetting resin used as the matrix resin of the composite material, an epoxy resin, a phenol resin, a benzoxazine resin, a vinyl ester resin, a bismaleimide resin, or the like is preferably used.

  As the thermoplastic resin used as the matrix resin of the composite material, general-purpose engineering plastics such as polyamide, polycarbonate and polyacetal are preferably used. Further, general-purpose plastics such as ABS, and heat-resistant polymers such as polyphenylene sulfide, polyether imide, polyether sulfone, polyether ether ketone, and liquid crystalline aromatic polyester may be used. Among these, it can be particularly suitably used for general-purpose engineering plastics such as polyamide, polycarbonate and polyacetal having a high molding temperature.

  The blending amount of the reinforcing fibers with respect to the matrix resin is not particularly limited and is appropriately selected according to the composite material to be produced. However, it is preferable to blend 5 to 30 parts by mass with respect to 100 parts by mass of the matrix resin.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

<Width, thickness and flatness measuring method of reinforcing fiber bundle>
The width of the reinforcing fiber bundle was measured with a precision of 0.5 mm using a metal scale. The thickness was measured with a precision of 0.01 mm using a micrometer. In addition, the sample took out each sample (fiber bundle) from each process, it left still on the flat place, and measured in the state of no tension. The number of measurements was 10 each, and the average value was used as each value. Furthermore, the average value of the width of the reinforcing fiber bundle was divided by the average value of the thickness to obtain the flatness of the reinforcing fiber bundle.

Example 1
The carbon fiber bundle was opened using the opening device configured as shown in FIG. The carbon fiber bundle was manufactured as follows. That is, the PAN fiber (single fiber fineness 0.7 dtex, filament number 24000), which is a precursor fiber, is flame-resistant at 250 ° C. in air until the fiber specific gravity becomes 1.35, and then the highest in a nitrogen gas atmosphere. Low temperature carbonization was performed at a temperature of 650 ° C. Thereafter, a carbon fiber bundle produced by high-temperature carbonization at 1300 ° C. in a nitrogen atmosphere is subjected to surface treatment by electrolytic oxidation using a 10.0% by mass ammonium sulfate aqueous solution, and a substantially untwisted carbon fiber bundle (tensile) Strength 4000 MPa, tensile modulus 240 GPa, 24,000 filaments, single fiber diameter 7 μm, fineness 1600 Tex). 0.4% by mass of a water-soluble urethane resin (Hydran AP-30 manufactured by DIC Corporation, film flow start temperature 110 to 115 ° C.) was applied to the carbon fiber bundle as a sizing agent. The width of the carbon fiber bundle before the fiber opening treatment was 9 mm (width per 1000 Tex: 5.6 mm), the thickness was 0.19 mm, and the flatness was 45.

  The diameters of the opening portions of the three opening bars with the same diameter were 50 mm, respectively, and the maximum diameter of the opening portion of the one different diameter opening bar was 52.1 mm. The radius of curvature r of the opening portion of the different-diameter opening bar was 70 mm. Further, the contact angles between the opening bar and the carbon fiber bundle were 51 ° for 12a, 108 ° for 12b, 104 ° for 12c, and 167 ° for 14b.

  The opening bar was subjected to chrome plating, and the surface roughness of the opening portion was Ra 0.25 μm.

  The tension of the carbon fiber bundle in the different-diameter opening bar was set to 0.75 g / tex, and the total contact time was set to 0.70 seconds. The temperature of the same-diameter opening bar was maintained at 150 ° C., and the temperature of the different-diameter opening bar was maintained at 150 ° C., and the carbon fiber bundle was supplied to the opening device. The width of the carbon fiber bundle immediately after passing through each opening bar was measured. The results are shown in Table 1.

  The width of the carbon fiber bundle after the fiber opening treatment was 24 mm (width: 15.0 mm per 1000 Tex), the thickness was 0.075 mm, and the flatness was 320.

  The obtained carbon fiber bundle was cut into a length of 6 mm to produce a carbon fiber chopped strand. The obtained chopped strand was excellent in heat resistance and dispersible in the matrix resin.

Comparative Example 1
A carbon fiber bundle was opened under the same conditions as in Example 1. However, the same-diameter opening bar was used instead of the different-diameter opening bar. The results are shown in Table 1.
The width of the carbon fiber bundle after the opening treatment was 11 mm (width per 1000 Tex: 6.8 mm), the thickness was 0.16 mm, and the flatness was 67. The obtained carbon fiber bundle was cut into a length of 6 mm to produce a carbon fiber chopped strand. Dispersibility of the obtained chopped strand in the matrix resin was insufficient.

Example 2
The carbon fiber bundle was opened under the same conditions as in Example 1 except that the surface temperature of the opening bar was changed from 150 ° C to 100 ° C. The results are shown in Table 1.
The width of the carbon fiber bundle after the opening treatment was 20 mm (width 12.5 mm per 1000 Tex), the thickness was 0.09 mm, and the flatness was 220.

Example 3
The carbon fiber bundle was opened under the same conditions as in Example 1 except that the surface temperature of the opening bar was changed from 150 ° C to 70 ° C. The results are shown in Table 1.
The width of the carbon fiber bundle after the fiber opening treatment was 13 mm (width per 1000 Tex: 8.1 mm), the thickness was 0.14 mm, and the flatness was 94.

Example 4
A carbon fiber bundle was opened under the same conditions as in Example 1 except that the amount of the sizing agent attached was changed from 0.4% by mass to 0.9% by mass. The results are shown in Table 1.
The width of the carbon fiber bundle after the fiber opening treatment was 17 mm (width 10.6 mm per 1000 Tex), the thickness was 0.105 mm, and the flatness ratio was 160.

Example 5
The carbon fiber bundle was opened under the same conditions as in Example 1 except that the carbon fiber bundle in the different-diameter opening bar was changed from a tension of 0.75 g / tex to 0.3 g / tex. The results are shown in Table 1.
The width of the carbon fiber bundle after the fiber opening treatment was 13 mm (width per 1000 Tex: 8.1 mm), the thickness was 0.14 mm, and the flatness was 94.

Example 6
The type of sizing agent used is changed from water-soluble urethane resin to water-dispersed polyester urethane resin (Bondic 1230NS, softening temperature 170-175 ° C by DIC Corporation), and the surface temperature of the opening bar is 180 ° C Opened the carbon fiber bundle under the same conditions as in Example 1.
The width of the carbon fiber bundle before the fiber opening treatment was 9 mm (width per 1000 Tex: 5.6 mm), the thickness was 0.19 mm, and the flatness was 45.
The width of the carbon fiber bundle after the opening treatment was 23 mm (14.3 mm width per 1000 Tex), the thickness was 0.08 mm, and the flatness was 305.

Example 7
The carbon fiber bundle was opened under the same conditions as in Example 1 except that the type of sizing agent used was changed from a water-soluble urethane resin to an epoxy resin (JER 1009, softening temperature 144 ° C., molecular weight 3800, manufactured by Mitsubishi Chemical Corporation). .
The width of the carbon fiber bundle before the fiber opening treatment was 9 mm (width per 1000 Tex: 5.6 mm), the thickness was 0.19 mm, and the flatness was 45.
The width of the carbon fiber bundle after the opening treatment was 23 mm (14.3 mm width per 1000 Tex), the thickness was 0.08 mm, and the flatness was 305.

DESCRIPTION OF SYMBOLS 100 Opening device 2 Reinforcing fiber bundle 4, 6 Conveying roller 8, 10 Tension adjusting roller 12a, 12b, 12c, 22 Same-diameter heat-opening bar 14, 24 Different-diameter heat-opening bar 16 Winder roller 18 Winding device 48, 54 Other end side 50, 56 Guide groove 52, 58 Bottom portion 58a, 58b Both ends 60 Center in width direction 80 Opening bar 82 Reinforcing fiber bundle 84 Contact start point 86 Location where reinforcing fiber bundle leaves α Center angle R1 Diameter R2 Diameter X Arrow

Claims (12)

The reinforcing fiber bundle is composed of at least two same-diameter opening bars sequentially arranged along the conveying direction of the reinforcing fiber bundle, and at least one different-diameter opening bar arranged in the subsequent stage. A fiber opening device for reinforcing fiber bundles that opens the reinforcing fiber bundle by winding and transporting the same diameter opening bar and then the different diameter opening bar,
The same-diameter opening bar is an opening bar whose diameter along the axial direction is the same,
The different-diameter fiber bars, Ri opening bars der in diameter formed by gradually increases toward the central portion from its axial ends,
The same-diameter opening bar and / or the different-diameter opening bar are supported non-rotatably along the axial direction thereof,
The same-diameter fiber bar and / or the different-diameter fiber bar surface roughness, characterized in Ra0.2~0.4μm der Rukoto,
Opening device for reinforcing fiber bundles.   The opening device according to claim 1, wherein a diameter of the same-diameter opening bar and a maximum diameter of the different-diameter opening bar are 10 to 200 mm, respectively.   The fiber opening device according to claim 1, wherein a guide groove is formed in the fiber opening bar having the same diameter and / or the fiber having a different diameter.   The fiber opening device according to claim 1, wherein the same-diameter opening bar and / or the different-diameter opening bar includes a heater therein.   The fiber-spreading apparatus according to claim 1, wherein the reinforcing fiber bundle is a carbon fiber bundle. The reinforcing fiber bundle is alternately repeated by straddling at least two same-diameter opening bars and at least one different-diameter opening bar disposed in the subsequent stage, straddling the upper surface or diving the lower surface. The same-diameter opening bar uses an opening bar having the same diameter along the axial direction, and the different-diameter opening bar extends from both axial ends to the center. As the diameter increases, the diameter gradually increases ,
The same-diameter opening bar and / or the different-diameter opening bar are supported non-rotatably along the axial direction thereof,
A method for opening a reinforcing fiber bundle using a fiber opening bar in which the surface roughness of the same diameter fiber opening bar and / or the different diameter fiber opening bar is Ra 0.2 to 0.4 μm. The method for opening a reinforcing fiber bundle according to claim 6 , wherein a surface temperature of the same-diameter opening bar and / or the different-diameter opening bar is 100 to 250 ° C. The method for opening a reinforcing fiber bundle according to claim 6 , wherein a contact angle between the same-diameter opening bar and / or the different-diameter opening bar and the reinforcing fiber bundle is 30 to 180 °. The method for opening a reinforcing fiber bundle according to claim 6 , wherein the total contact time between the same-diameter opening bar and / or the different-diameter opening bar and the reinforcing fiber bundle is 0.5 to 120 seconds. The method for opening a reinforcing fiber bundle according to claim 6 , wherein the reinforcing fiber bundle is brought into sliding contact with the different-diameter opening bar while applying a tension of 0.5 to 5 g / tex to the reinforcing fiber bundle. It is a reinforcing fiber bundle to which a sizing agent containing 60% by mass or more of a resin having a softening temperature or a flow start temperature of 100 to 300 ° C. as a nonvolatile component is attached at 25 ° C., and the width per 1000 Tex is 8 mm or more. Is a reinforcing fiber bundle.   The reinforcing fiber bundle according to claim 11, wherein the flatness ratio is 250 to 500.

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